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Sample records for biofunctionalized electrospun silk

  1. Addition of selenium nanoparticles to electrospun silk scaffolds improves mammalian cell activity while reducing bacterial growth

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    Stanley Chung

    2016-07-01

    Full Text Available Silk possesses many beneficial wound healing properties, and electrospun scaffolds are especially applicable for skin applications, due to their smaller interstices and higher surface areas compared to non-electrospun equivalents. However, purified silk promotes microbial growth. In contrast, selenium nanoparticles have excellent antibacterial properties and are a novel antimicrobial chemistry. Here, electrospun silk scaffolds were doped with selenium nanoparticles to impart antibacterial properties to the silk scaffolds. Results showed significantly improved bacterial inhibition and improvement in human dermal fibroblast metabolic activity. These results suggest that the addition of selenium nanoparticles to electrospun silk is a promising approach to improve wound healing with reduced infection, without relying on antibiotics.

  2. A novel electrospun silk fibroin/hydroxyapatite hybrid nanofibers

    International Nuclear Information System (INIS)

    Ming, Jinfa; Zuo, Baoqi

    2012-01-01

    A novel electrospinning of silk fibroin/hydroxyapatite hybrid nanofibers with different composition ratios was performed with methanoic acid as a spinning solvent. The silk fibroin/hydroxyapatite hybrids containing up to 30% hydroxyapatite nanoparticles could be electrospun into the continuous fibrous structure. The electrospun silk fibroin/hydroxyapatite hybrid nanofibers showed bigger diameter and wider diameter distribution than pure silk fibroin nanofibers, and the average diameter gradually increased from 95 to 582 nm. At the same time, the secondary structure of silk fibroin/hydroxyapatite nanofibers was characterized by X-ray diffraction, Fourier transform infrared analysis, and DSC measurement. Comparing with the pure silk fibroin nanofibers, the crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. X-ray diffraction results demonstrated the hydroxyapatite crystalline nature remained as evidenced from the diffraction planes (002), (211), (300), and (202) of the hydroxyapatite crystallites, which was also confirmed by Fourier transform infrared analysis. The thermal behavior of hybrid nanofibers exhibited the endothermic peak of moisture evaporation ranging from 86 to 113 °C, and the degradation peak at 286 °C appeared. The SF/HAp nanofibers mats containing 30% HAp nanoparticles showed higher breaking tenacity and extension at break for 1.1688 ± 0.0398 MPa and 6.55 ± 1.95%, respectively. Therefore, the electrospun silk fibroin/hydroxyapatite hybrid nanofibers should be provided potentially useful options for the fabrication of biomaterial scaffolds for bone tissue engineering. -- Highlights: ► The novel SF/HAp nanofibers were directly prepared by electrospinning method. ► The nanofiber diameter had significant related to the content of HAp. ► The crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. ► The HAp crystals existing in the hybrid nanofibers were characterized

  3. Fabrication and Biocompatibility of Electrospun Silk Biocomposites

    Directory of Open Access Journals (Sweden)

    Ick-Soo Kim

    2011-10-01

    Full Text Available Silk fibroin has attracted great interest in tissue engineering because of its outstanding biocompatibility, biodegradability and minimal inflammatory reaction. In this study, two kinds of biocomposites based on regenerated silk fibroin are fabricated by electrospinning and post-treatment processes, respectively. Firstly, regenerated silk fibroin/tetramethoxysilane (TMOS hybrid nanofibers with high hydrophilicity are prepared, which is superior for fibroblast attachment. The electrospinning process causes adjacent fibers to ‘weld’ at contact points, which can be proved by scanning electron microscope (SEM. The water contact angle of silk/tetramethoxysilane (TMOS composites shows a sharper decrease than pure regenerated silk fibroin nanofiber, which has a great effect on the early stage of cell attachment behavior. Secondly, a novel tissue engineering scaffold material based on electrospun silk fibroin/nano-hydroxyapatite (nHA biocomposites is prepared by means of an effective calcium and phosphate (Ca–P alternate soaking method. nHA is successfully produced on regenerated silk fibroin nanofiber within several min without any pre-treatments. The osteoblastic activities of this novel nanofibrous biocomposites are also investigated by employing osteoblastic-like MC3T3-E1 cell line. The cell functionality such as alkaline phosphatase (ALP activity is ameliorated on mineralized silk nanofibers. All these results indicate that this silk/nHA biocomposite scaffold material may be a promising biomaterial for bone tissue engineering.

  4. Compliant electrospun silk fibroin tubes for small vessel bypass grafting.

    Science.gov (United States)

    Marelli, Benedetto; Alessandrino, Antonio; Farè, Silvia; Freddi, Giuliano; Mantovani, Diego; Tanzi, Maria Cristina

    2010-10-01

    Processing silk fibroin (SF) by electrospinning offers a very attractive opportunity for producing three-dimensional nanofibrillar matrices in tubular form, which may be useful for a biomimetic approach to small calibre vessel regeneration. Bypass grafting of small calibre vessels, with a diameter less than 6mm, is performed mainly using autografts, like the saphenous vein or internal mammary artery. At present no polymeric grafts made of SF are commercially available, mainly due to inadequate properties (low compliance and lack of endothelium cells). The aim of this work was to electrospin SF into tubular structures (Ø=6mm) for small calibre vessel grafting, characterize the morphological, chemico-physical and mechanical properties of the electrospun SF structures and to validate their potential to interact with cells. The morphological properties of electrospun SF nanofibres were investigated by scanning electron microscopy. Chemico-physical analyses revealed an increase in the crystallinity of the structure of SF nanofibres on methanol treatment. Mechanical tests, i.e. compliance and burst pressure measurements, of the electrospun SF tubes showed that the inner pressure to radial deformation ratio was linear for elongation up to 15% and pressure up to 400 mm Hg. The mean compliance value between 80 and 120 mm Hg was higher than the values reported for both Goretex(R) and Dacron(R) grafts and for bovine heterografts, but still slightly lower than those of saphenous and umbilical vein, which nowadays represent the gold standard for the replacement of small calibre arteries. The electrospun tubes resisted up to 575+/-17 mmHg, which is more than four times the upper physiological pressure of 120 mmHg and more than twice the pathological upper pressures (range 180-220 mmHg). The in vitro tests showed a good cytocompatibility of the electrospun SF tubes. Therefore, the electrospun SF tubes developed within this work represent a suitable candidate for small calibre

  5. A new electrospun graphene-silk fibroin composite scaffolds for guiding Schwann cells.

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    Zhao, Yahong; Gong, Jiahuan; Niu, Changmei; Wei, Ziwei; Shi, Jiaqi; Li, Guohui; Yang, Yumin; Wang, Hongbo

    2017-12-01

    Graphene (Gr) has been made of various forms used for repairing peripheral nerve injury with favorable electroactivity, however, graphene-based scaffolds in peripheral nerve regeneration are still rarely reported due to the difficulty of realizing uniform dispersion of graphene and electroactive materials at nanoscale as well as lacking biocompatibility. In this paper, graphene-silk fibroin (SF) composite nanofiber membranes with different mass ratios were prepared via electrospinning. Microscopic observation revealed that electrospun Gr/SF membranes had a nanofibrous structure. Electrochemical analysis provided electroactivity characterization of the Gr/SF membranes. The physiochemical results showed that the physiochemical properties of electrospun Gr/SF membranes could be changed by varying Gr concentration. Swelling ratio and contact angle measurements confirmed that electrospun Gr/SF membranes possessed large absorption capacity and hydrophilic surface, and the mechanical property was improved with increasing Gr concentration. Additionally, in-vitro cytotoxicity with L929 revealed that all the electrospun Gr/SF membranes are biocompatible. Moreover, the morphology and quantity showed that the membranes supported the survival and growth of the cultured Schwann cells. Collectively, all of the results suggest that the electrospun Gr/SF membranes combine the excellent electrically conductivity and mechanical strength of the graphene with biocompatibility property of silk to mimic the natural neural cell micro-environment for nerve development.

  6. Mechanically-reinforced electrospun composite silk fibroin nanofibers containing hydroxyapatite nanoparticles

    International Nuclear Information System (INIS)

    Kim, Hyunryung; Che, Lihua; Ha, Yoon; Ryu, WonHyoung

    2014-01-01

    Electrospun silk fibroin (SF) scaffolds provide large surface area, high porosity, and interconnection for cell adhesion and proliferation and they may replace collagen for many tissue engineering applications. Despite such advantages, electrospun SF scaffolds are still limited as bone tissue replacement due to their low mechanical strengths. While enhancement of mechanical strengths by incorporating inorganic ceramics into polymers has been demonstrated, electrospinning of a mixture of SF and inorganic ceramics such as hydroxyapatite is challenging and less studied due to the aggregation of ceramic particles within SF. In this study, we aimed to enhance the mechanical properties of electrospun SF scaffolds by uniformly dispersing hydroxyapatite (HAp) nanoparticles within SF nanofibers. HAp nanoaprticles were modified by γ-glycidoxypropyltrimethoxysilane (GPTMS) for uniform dispersion and enhanced interfacial bonding between HAp and SF fibers. Optimal conditions for electrospinning of SF and GPTMS-modified HAp nanoparticles were identified to achieve beadless nanofibers without any aggregation of HAp nanoparticles. The MTT and SEM analysis of the osteoblasts-cultured scaffolds confirmed the biocompatibility of the composite scaffolds. The mechanical properties of the composite scaffolds were analyzed by tensile tests for the scaffolds with varying contents of HAp within SF fibers. The mechanical testing showed the peak strengths at the HAp content of 20 wt.%. The increase of HAp content up to 20 wt.% increased the mechanical properties of the composite scaffolds, while further increase above 20 wt.% disrupted the polymer chain networks within SF nanofibers and weakened the mechanical strengths. - Highlights: • Electrospun composite silk fibroin scaffolds were mechanically-reinforced. • GPTMS enhanced hydroxyapatite distribution in silk fibroin nanofibers. • Mechanical property of composite scaffolds increased up to 20% of hydroxyapatite. • Composite

  7. Analysis of the Comprehensive Tensile Relationship in Electrospun Silk Fibroin/Polycaprolactone Nanofiber Membranes.

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    Yin, Yunlei; Pu, Dandan; Xiong, Jie

    2017-12-07

    The mechanical properties of electrospun nanofiber membranes are critical for their applications. A clear understanding of the mechanical properties that result from the characteristics of the individual fiber and membrane microstructure is vital in the design of fiber composites. In this reported study, silk fibroin (SF)/polycaprolactone (PCL) composite nanofiber membranes were preparedusing an electrostatic spinning technology. The nanofiber orientation distribution (FOD) of the membrane was analyzed using multi-layer image fusion technology, and the results indicated the presence of an approximately uniform distribution of fibers in the electrospun membranes. The relationship between the single nanofiber and the membrane was established by analyzing the geometrical structure of the cell by employing a representative volume element (RVE) analysis method. The mechanical properties of the 272 nm diameter SF/PCL composite fibers were then predicted using the developed model.

  8. Enhancing surface properties of breast implants by using electrospun silk fibroin.

    Science.gov (United States)

    Valencia-Lazcano, A A; Román-Doval, R; De La Cruz-Burelo, E; Millán-Casarrubias, E J; Rodríguez-Ortega, A

    2017-08-24

    In the present study, a new electrospun silk fibroin coating of silicone breast implants with improved biocompatibility and mechanical properties was obtained. Fibrous scaffolds were produced by electrospinning a solution containing silk fibroin, derived from Bombyx mori cocoons, and polyethylene oxide (PEO) to be used as a coating of breast implants. A randomly oriented structure of fibroin/PEO was electrospun on implants as assessed by SEM analysis, roughness measurements and ATR-FTIR spectroscopy. The scaffold showed 0.25 µm diameter fibres, 0.76 µm size superficial pores, arithmetic roughness of 0.632 ± 0.12 µm and texture aspect ratio of 0.893 ± 0.04. ATR-FTIR spectroscopy demonstrates the presence of PEO and fibroin in the coating. The mechanical characterisation of the implants before and after being coated with fibroin/PEO demonstrated that the fibroin/PEO scaffold contributes to the increase in the elastic modulus from 0.392 ± 0.02 to 0.560 ± 0.03 MPa and to a more elastic behaviour of the breast implants. Using the fibroin/PEO coating, human fibroblasts seeded on this matrix increased viability up to 30% compared to conventional breast implants. Electrospun silk fibroin could represent a clinically compatible, viable form to coat breast implants. Low cytotoxicity by the fibroin coating and its physico-chemical and mechanical properties may find application in improving breast implants biocompatibility. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  9. Preliminary investigation of airgap electrospun silk-fibroin-based structures for ligament analogue engineering.

    Science.gov (United States)

    Sell, S A; McClure, M J; Ayres, C E; Simpson, D G; Bowlin, G L

    2011-01-01

    The process of electrospinning has proven to be highly beneficial for use in a number of tissue-engineering applications due to its ease of use, flexibility and tailorable properties. There have been many publications on the creation of aligned fibrous structures created through various forms of electrospinning, most involving the use of a metal target rotating at high speeds. This work focuses on the use of a variation known as airgap electrospinning, which does not use a metal collecting target but rather a pair of grounded electrodes equidistant from the charged polymer solution to create highly aligned 3D structures. This study involved a preliminary investigation and comparison of traditionally and airgap electrospun silk-fibroin-based ligament constructs. Structures were characterized with SEM and alignment FFT, and underwent porosity, permeability, and mechanical anisotropy evaluation. Preliminary cell culture with human dermal fibroblasts was performed to determine the degree of cellular orientation and penetration. Results showed airgap electrospun structures to be anisotropic with significantly increased porosity and cellular penetration compared to their traditionally electrospun counterparts.

  10. Membrane-reinforced three-dimensional electrospun silk fibroin scaffolds for bone tissue engineering

    International Nuclear Information System (INIS)

    Yang, Sung Yeun; Hwang, Tae Heon; Ryu, WonHyoung; Che, Lihua; Oh, Jin Soo; Ha, Yoon

    2015-01-01

    Electrospun silk fibroin (SF) scaffolds have drawn much attention because of their resemblance to natural tissue architecture such as extracellular matrix, and the biocompatibility of SF as a candidate material to replace collagen. However, electrospun scaffolds lack the physical integrity of bone tissue scaffolds, which require resistance to mechanical loadings. In this work, we propose membrane-reinforced electrospun SF scaffolds by a serial process of electrospinning and freeze-drying of SF solutions in two different solvents: formic acid and water, respectively. After wet electrospinning followed by replacement of methanol with water, SF nanofibers dispersed in water were mixed with aqueous SF solution. Freeze-drying of the mixed solution resulted in 3D membrane-connected SF nanofibrous scaffolds (SF scaffolds) with a thickness of a few centimeters. We demonstrated that the SF concentration of aqueous SF solution controlled the degree of membrane reinforcement between nanofibers. It was also shown that both increase in degree of membrane reinforcement and inclusion of hydroxyapatite (HAP) nanoparticles resulted in higher resistance to compressive loadings of the SF scaffolds. Culture of human osteoblasts on collagen, SF, and SF-HAP scaffolds showed that both SF and SF-HAP scaffolds had biocompatibility and cell proliferation superior to that of the collagen scaffolds. SF-HAP scaffolds with and without BMP-2 were used for in vivo studies for 4 and 8 weeks, and they showed enhanced bone tissue formation in rat calvarial defect models. (paper)

  11. Biofunctionalized Lysophosphatidic Acid/Silk Fibroin Film for Cornea Endothelial Cell Regeneration

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    Jeon, Hayan; Oliveira, Joaquim Miguel; Reis, Rui Luis; Khang, Gilson

    2018-01-01

    Cornea endothelial cells (CEnCs) tissue engineering is a great challenge to repair diseased or damaged CEnCs and require an appropriate biomaterial to support cell proliferation and differentiation. Biomaterials for CEnCs tissue engineering require biocompatibility, tunable biodegradability, transparency, and suitable mechanical properties. Silk fibroin-based film (SF) is known to meet these factors, but construction of functionalized graft for bioengineering of cornea is still a challenge. Herein, lysophosphatidic acid (LPA) is used to maintain and increase the specific function of CEnCs. The LPA and SF composite film (LPA/SF) was fabricated in this study. Mechanical properties and in vitro studies were performed using a rabbit model to demonstrate the characters of LPA/SF. ATR-FTIR was characterized to identify chemical composition of the films. The morphological and physical properties were performed by SEM, AFM, transparency, and contact angle. Initial cell density and MTT were performed for adhesion and cell viability in the SF and LPA/SF film. Reverse transcription polymerase chain reactions (RT-PCR) and immunofluorescence were performed to examine gene and protein expression. The results showed that films were designed appropriately for CEnCs delivery. Compared to pristine SF, LPA/SF showed higher biocompatibility, cell viability, and expression of CEnCs specific genes and proteins. These indicate that LPA/SF, a new biomaterial, offers potential benefits for CEnCs tissue engineering for regeneration. PMID:29710848

  12. Electrospun silk-elastin-like fibre mats for tissue engineering applications

    International Nuclear Information System (INIS)

    Machado, Raul; Da Costa, André; Padrão, Jorge; Gomes, Andreia; Casal, Margarida; Sencadas, Vitor; Costa, Carlos M; Lanceros-Méndez, Senentxu; Garcia-Arévalo, Carmen; Rodríguez-Cabello, José Carlos

    2013-01-01

    Protein-based polymers are present in a wide variety of organisms fulfilling structural and mechanical roles. Advances in protein engineering and recombinant DNA technology allow the design and production of recombinant protein-based polymers (rPBPs) with an absolute control of its composition. Although the application of recombinant proteins as biomaterials is still an emerging technology, the possibilities are limitless and far superior to natural or synthetic materials, as the complexity of the structural design can be fully customized. In this work, we report the electrospinning of two new genetically engineered silk-elastin-like proteins (SELPs) consisting of alternate silk- and elastin-like blocks. Electrospinning was performed with formic acid and aqueous solutions at different concentrations without addition of further agents. The size and morphology of the electrospun structures was characterized by scanning electron microscopy showing its dependence on the concentration and solvent used. Treatment with methanol-saturated air was employed to stabilize the structure and promote water insolubility through a time-dependent conversion of random coils into β-sheets (FTIR). The resultant methanol-treated electrospun mats were characterized for swelling degree (570–720%), water vapour transmission rate (1083 g/m 2 /day) and mechanical properties (modulus of elasticity ∼126 MPa). Furthermore, the methanol-treated SELP fibre mats showed no cytotoxicity and were able to support adhesion and proliferation of normal human skin fibroblasts. Adhesion was characterized by a filopodia-mediated mechanism. These results demonstrate that SELP fibre mats can provide promising solutions for the development of novel biomaterials suitable for tissue engineering applications. (paper)

  13. Electrospun silk fibroin fibers for storage and controlled release of human platelet lysate.

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    Pignatelli, Cataldo; Perotto, Giovanni; Nardini, Marta; Cancedda, Ranieri; Mastrogiacomo, Maddalena; Athanassiou, Athanassia

    2018-04-17

    Human platelet lysate (hPL) is a pool of growth factors and cytokines able to induce regeneration of different tissues. Despite its good potentiality as therapeutic tool for regenerative medicine applications, hPL has been only moderately exploited in this field. A more widespread adoption has been limited because of its rapid degradation at room temperature that decreases its functionality. Another limiting factor for its extensive use is the difficulty of handling the hPL gels. In this work, silk fibroin-based patches were developed to address several points: improving the handling of hPL, enabling their delivery in a controlled manner and facilitating their storage by creating a device ready to use with expanded shelf life. Patches of fibroin loaded with hPL were synthesized by electrospinning to take advantage of the fibrous morphology. The release kinetics of the material was characterized and tuned through the control of fibroin crystallinity. Cell viability assays, performed with primary human dermal fibroblasts, demonstrated that fibroin is able to preserve the hPL biological activity and prolong its shelf-life. The strategy of storing and preserving small active molecules within a naturally-derived, protein-based fibrous scaffold was successfully implemented, leading to the design of a biocompatible device, which can potentially simplify the storage and the application of the hPL on a human patient, undergoing medical procedures such as surgery and wound care. Human platelets lysate (hPL) is a mixture of growth factors and cytokines able to induce the regeneration of damaged tissues. This study aims at enclosing hPL in a silk fibroin electrospun matrix to expand its utilization. Silk fibroin showed the ability to preserve the hPL activity at temperature up to 60 °C and the manipulation of fibroin's crystallinity provided a tool to modulate the hPL release kinetic. This entails the possibility to fabricate the hPL silk fibroin patches in advance and

  14. Precipitation of hydroxyapatite on electrospun polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds for bone tissue engineering.

    Science.gov (United States)

    Shanmugavel, Suganya; Reddy, Venugopal Jayarama; Ramakrishna, Seeram; Lakshmi, B S; Dev, Vr Giri

    2014-07-01

    Advances in electrospun nanofibres with bioactive materials have enhanced the scope of fabricating biomimetic scaffolds for tissue engineering. The present research focuses on fabrication of polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds by electrospinning followed by hydroxyapatite deposition by calcium-phosphate dipping method for bone tissue engineering. Morphology, composition, hydrophilicity and mechanical properties of polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds along with controls polycaprolactone and polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds were examined by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle and tensile tests, respectively. Adipose-derived stem cells cultured on polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds displayed highest cell proliferation, increased osteogenic markers expression (alkaline phosphatase and osteocalcin), osteogenic differentiation and increased mineralization in comparison with polycaprolactone control. The obtained results indicate that polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds have appropriate physico-chemical and biological properties to be used as biomimetic scaffolds for bone tissue regeneration. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  15. Electrospun composites of PHBV, silk fibroin and nano-hydroxyapatite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Paşcu, Elena I.; Stokes, Joseph; McGuinness, Garrett B., E-mail: garrett.mcguinness@dcu.ie

    2013-12-01

    Electrospinning of fibrous scaffolds containing nano-hydroxyapatite (nHAp) embedded in a matrix of functional biomacromolecules offers an attractive route to mimicking the natural bone tissue architecture. Functional fibrous substrates will support cell attachment, proliferation and differentiation, while the role of HAp is to induce cells to secrete extracellular matrix (ECM) for mineralization to form bone. Electrospinning of biomaterials composed of polyhydroxybutyrate-co-(3-hydroxyvalerate) with 2% valerate fraction (PHBV), nano-hydroxyapatite (nHAp), and Bombyx mori silk fibroin essence (SF), Mw = 90KDa, has been achieved for nHAp and SF solution concentrations of 2 (w/vol) % each and 5 (w/vol) % each. The structure and properties of the nanocomposite fibrous membranes were investigated by means of Scanning Electron Microscopy in combination with Energy Dispersive X-Ray Analysis (SEM/EDX), Fourier Transformed Infrared Spectroscopy (FT-IR), uniaxial tensile and compressive mechanical testing, degradation tests and in vitro bioactivity tests. SEM images showed smooth, uniform and continuous fibre deposition with no bead formation, and fibre diameters of between 10 and 15 μm. EDX and FT-IR confirmed the presence of nHAp and SF. After one month in deionised water, tests showed less than 2% weight loss with the samples retaining their fibrous morphology, confirming that this material biodegrades slowly. After 28 days of immersion in Simulated Body Fluid (SBF) an apatite layer was visible on the surface of the fibres, proving their bioactivity. Preliminary in vitro biological assessment showed that after 1 and 3 days in culture, cells were attached to the fibres, retaining their morphology while presenting a flattened appearance and elongated shape on the surface of fibres. Young's modulus was found to increase from 0.7 kPa (± 0.33 kPa) for electrospun samples of PHBV only to 1.4 kPa (± 0.54 kPa) for samples with 2 (w/vol) % each of nHAp and SF. Samples

  16. Electrospun composites of PHBV, silk fibroin and nano-hydroxyapatite for bone tissue engineering

    International Nuclear Information System (INIS)

    Paşcu, Elena I.; Stokes, Joseph; McGuinness, Garrett B.

    2013-01-01

    Electrospinning of fibrous scaffolds containing nano-hydroxyapatite (nHAp) embedded in a matrix of functional biomacromolecules offers an attractive route to mimicking the natural bone tissue architecture. Functional fibrous substrates will support cell attachment, proliferation and differentiation, while the role of HAp is to induce cells to secrete extracellular matrix (ECM) for mineralization to form bone. Electrospinning of biomaterials composed of polyhydroxybutyrate-co-(3-hydroxyvalerate) with 2% valerate fraction (PHBV), nano-hydroxyapatite (nHAp), and Bombyx mori silk fibroin essence (SF), Mw = 90KDa, has been achieved for nHAp and SF solution concentrations of 2 (w/vol) % each and 5 (w/vol) % each. The structure and properties of the nanocomposite fibrous membranes were investigated by means of Scanning Electron Microscopy in combination with Energy Dispersive X-Ray Analysis (SEM/EDX), Fourier Transformed Infrared Spectroscopy (FT-IR), uniaxial tensile and compressive mechanical testing, degradation tests and in vitro bioactivity tests. SEM images showed smooth, uniform and continuous fibre deposition with no bead formation, and fibre diameters of between 10 and 15 μm. EDX and FT-IR confirmed the presence of nHAp and SF. After one month in deionised water, tests showed less than 2% weight loss with the samples retaining their fibrous morphology, confirming that this material biodegrades slowly. After 28 days of immersion in Simulated Body Fluid (SBF) an apatite layer was visible on the surface of the fibres, proving their bioactivity. Preliminary in vitro biological assessment showed that after 1 and 3 days in culture, cells were attached to the fibres, retaining their morphology while presenting a flattened appearance and elongated shape on the surface of fibres. Young's modulus was found to increase from 0.7 kPa (± 0.33 kPa) for electrospun samples of PHBV only to 1.4 kPa (± 0.54 kPa) for samples with 2 (w/vol) % each of nHAp and SF. Samples

  17. Electrospun composites of PHBV, silk fibroin and nano-hydroxyapatite for bone tissue engineering.

    Science.gov (United States)

    Paşcu, Elena I; Stokes, Joseph; McGuinness, Garrett B

    2013-12-01

    Electrospinning of fibrous scaffolds containing nano-hydroxyapatite (nHAp) embedded in a matrix of functional biomacromolecules offers an attractive route to mimicking the natural bone tissue architecture. Functional fibrous substrates will support cell attachment, proliferation and differentiation, while the role of HAp is to induce cells to secrete extracellular matrix (ECM) for mineralization to form bone. Electrospinning of biomaterials composed of polyhydroxybutyrate-co-(3-hydroxyvalerate) with 2% valerate fraction (PHBV), nano-hydroxyapatite (nHAp), and Bombyx mori silk fibroin essence (SF), Mw=90KDa, has been achieved for nHAp and SF solution concentrations of 2 (w/vol) % each and 5 (w/vol) % each. The structure and properties of the nanocomposite fibrous membranes were investigated by means of Scanning Electron Microscopy in combination with Energy Dispersive X-Ray Analysis (SEM/EDX), Fourier Transformed Infrared Spectroscopy (FT-IR), uniaxial tensile and compressive mechanical testing, degradation tests and in vitro bioactivity tests. SEM images showed smooth, uniform and continuous fibre deposition with no bead formation, and fibre diameters of between 10 and 15 μm. EDX and FT-IR confirmed the presence of nHAp and SF. After one month in deionised water, tests showed less than 2% weight loss with the samples retaining their fibrous morphology, confirming that this material biodegrades slowly. After 28 days of immersion in Simulated Body Fluid (SBF) an apatite layer was visible on the surface of the fibres, proving their bioactivity. Preliminary in vitro biological assessment showed that after 1 and 3 days in culture, cells were attached to the fibres, retaining their morphology while presenting a flattened appearance and elongated shape on the surface of fibres. Young's modulus was found to increase from 0.7 kPa (±0.33 kPa) for electrospun samples of PHBV only to 1.4 kPa (±0.54 kPa) for samples with 2 (w/vol) % each of nHAp and SF. Samples prepared with

  18. Electrospun Collagen/Silk Tissue Engineering Scaffolds: Fiber Fabrication, Post-Treatment Optimization, and Application in Neural Differentiation of Stem Cells

    Science.gov (United States)

    Zhu, Bofan

    Biocompatible scaffolds mimicking the locally aligned fibrous structure of native extracellular matrix (ECM) are in high demand in tissue engineering. In this thesis research, unidirectionally aligned fibers were generated via a home-built electrospinning system. Collagen type I, as a major ECM component, was chosen in this study due to its support of cell proliferation and promotion of neuroectodermal commitment in stem cell differentiation. Synthetic dragline silk proteins, as biopolymers with remarkable tensile strength and superior elasticity, were also used as a model material. Good alignment, controllable fiber size and morphology, as well as a desirable deposition density of fibers were achieved via the optimization of solution and electrospinning parameters. The incorporation of silk proteins into collagen was found to significantly enhance mechanical properties and stability of electrospun fibers. Glutaraldehyde (GA) vapor post-treatment was demonstrated as a simple and effective way to tune the properties of collagen/silk fibers without changing their chemical composition. With 6-12 hours GA treatment, electrospun collagen/silk fibers were not only biocompatible, but could also effectively induce the polarization and neural commitment of stem cells, which were optimized on collagen rich fibers due to the unique combination of biochemical and biophysical cues imposed to cells. Taken together, electrospun collagen rich composite fibers are mechanically strong, stable and provide excellent cell adhesion. The unidirectionally aligned fibers can accelerate neural differentiation of stem cells, representing a promising therapy for neural tissue degenerative diseases and nerve injuries.

  19. Fabrication of electrospun silk fibroin scaffolds coated with graphene oxide and reduced graphene for applications in biomedicine.

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    Aznar-Cervantes, Salvador; Martínez, Jose G; Bernabeu-Esclapez, Antonia; Lozano-Pérez, A Abel; Meseguer-Olmo, Luis; Otero, Toribio F; Cenis, Jose L

    2016-04-01

    Silk fibroin and graphene are both promising biomaterials described in the bibliography. Hybrid scaffolds combining their properties could be attractive for tissue engineering applications. In this work, a new methodology to produce electrospun fibroin scaffolds coated with graphene materials is provided. The mechanical, electrical and electrochemical properties of the materials attained were characterised. The fibre diameters were measured (from 3.9 to 5.2 μm). The samples coated with reduced grapheme were electronic conductors and electroactive in liquid electrolytes, showing maximum oxidation and reduction (around−0.4 V peak). The chronoamperometric responses showed a reduction shoulder, pointing to the entrance of balancing cations from the solution by nucleation–relaxation: the reaction induced structural changes in the graphene. In order to check the biocompatibility of the materials, they were seeded with L929 fibroblasts. The excellent biocompatibility of silk fibroin meshes was maintained after coating with graphene, being the proliferation results equal in all the treatments 7 days after the seeding (Tukey, p N 0.05).The conductive and electroactive properties of meshes coated with reduced graphene allow the potential application of local electric fields or local ionic currents to cell cultures, biological interfaces or animal models without host response.

  20. Electrospun silk fibroin scaffolds coated with reduced graphene promote neurite outgrowth of PC-12 cells under electrical stimulation.

    Science.gov (United States)

    Aznar-Cervantes, Salvador; Pagán, Ana; Martínez, Jose G; Bernabeu-Esclapez, Antonia; Otero, Toribio F; Meseguer-Olmo, Luis; Paredes, Juan I; Cenis, Jose L

    2017-10-01

    Novel approaches to neural research require biocompatible materials capable to act as electrode structures or scaffolds for tissue engineering in order to stimulate or restore the functionality of damaged tissues. This work offers promising results that indicate the potential use of electrospun silk fibroin (SF) scaffolds coated with reduced graphene oxide (rGO) in this sense. The coated material becomes conductor and electroactive. A complete characterisation of SF/rGO scaffolds is provided in terms of electrochemistry, mechanical behaviour and chemical conformation of fibroin. The excellent biocompatibility of this novel material is proved with cultures of PC-12 cells. The coating with rGO improved the adhesion of cells in comparison with cells growing onto the surface of pure SF scaffolds. Also, the use of SF/rGO scaffolds combined with electrical stimulation promoted the differentiation into neural phenotypes reaching comparable or even superior levels to those obtained by means of the traditional treatment with neural growth factor (NGF). Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Mechanical property and biological performance of electrospun silk fibroin-polycaprolactone scaffolds with aligned fibers.

    Science.gov (United States)

    Yuan, Han; Shi, Hongfei; Qiu, Xushen; Chen, Yixin

    2016-01-01

    The mechanical strength, biocompatibility, and sterilizability of silk fibroin allow it to be a possible candidate as a natural bone regenerate material. To improve mechanical character and reinforce the cell movement induction, silk fibroin (SF)-polycaprolactone (PCL) alloy was fabricated by electrospinning techniques with a rotating collector to form aligned fibrous scaffolds and random-oriented scaffolds. The scanning electron microscope image of the scaffold and the mechanical properties of the scaffold were investigated by tensile mechanical tests, which were compared to random-oriented scaffolds. Furthermore, mesenchymal stem cells were planted on these scaffolds to investigate the biocompatibility, elongation, and cell movement in situ. Scanning electron microscopy shows that 91% fibers on the aligned fibroin scaffold were distributed between the dominant direction ±10°. With an ideal support for stem cell proliferation in vitro, the aligned fibrous scaffold induces cell elongation at a length of 236.46 ± 82 μm and distribution along the dominant fiber direction with a cell alignment angle at 6.57° ± 4.45°. Compared with random-oriented scaffolds made by artificial materials, aligned SF-PCL scaffolds could provide a moderate mesenchymal stem cell engraftment interface and speed up early stage cell movement toward the bone defect.

  2. Directing osteogenesis of stem cells with hydroxyapatite precipitated electrospun eri-tasar silk fibroin nanofibrous scaffold.

    Science.gov (United States)

    Panda, N; Bissoyi, A; Pramanik, K; Biswas, A

    2014-01-01

    Stimulating stem cell differentiation without growth factor supplement offers a potent and cost-effective scaffold for tissue regeneration. We hypothesise that surface precipitation of nano-hydroxyapatite (nHAp) over blends of non-mulberry silk fibroin with better hydrophilicity and RGD amino acid sequences can direct the stem cell towards osteogenesis. This report focuses on the fabrication of a blended eri-tasar silk fibroin nanofibrous scaffold (ET) followed by nHAp deposition by a surface precipitation (alternate soaking in calcium and phosphate solution) method. Morphology, hydrophilicity, composition, and the thermal and mechanical properties of ET/nHAp were examined by field emission scanning electron microscopy, TEM, FT-IR, X-ray diffraction, TGA and contact angle measurement and compared with ET. The composite scaffold demonstrated improved thermal stability and surface hydrophilicity with an increase in stiffness and elastic modulus (778 ± 2.4 N/m and 13.1 ± 0.36 MPa) as compared to ET (160.6 ± 1.34 N/m and 8.3 ± 0.4 MPa). Mineralisation studies revealed an enhanced and more uniform surface deposition of HAp-like crystals, while significant differences in cellular viability and attachment were observed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and confocal microscopy study. The cell viability and expression of adhesion molecules (CD 44 and CD 29) are found to be optimum for subsequent stages of growth proliferation and differentiation. The rates of proliferation have been observed to decrease owing to the transition of MSC from a state of proliferation to a state of differentiation. The confirmation of improved osteogenic differentiation was finally verified through the alkaline phosphatase assay, pattern of gene expression related to osteogenic differentiation and morphological observations of differentiated cord blood human mesenchymal stem cells under fluorescence microscope. The results

  3. Small diameter electrospun silk fibroin vascular grafts: Mechanical properties, in vitro biodegradability, and in vivo biocompatibility.

    Science.gov (United States)

    Catto, Valentina; Farè, Silvia; Cattaneo, Irene; Figliuzzi, Marina; Alessandrino, Antonio; Freddi, Giuliano; Remuzzi, Andrea; Tanzi, Maria Cristina

    2015-09-01

    To overcome the drawbacks of autologous grafts currently used in clinical practice, vascular tissue engineering represents an alternative approach for the replacement of small diameter blood vessels. In the present work, the production and characterization of small diameter tubular matrices (inner diameter (ID)=4.5 and 1.5 mm), obtained by electrospinning (ES) of Bombyx mori silk fibroin (SF), have been considered. ES-SF tubular scaffolds with ID=1.5 mm are original, and can be used as vascular grafts in pediatrics or in hand microsurgery. Axial and circumferential tensile tests on ES-SF tubes showed appropriate properties for the specific application. The burst pressure and the compliance of ES-SF tubes were estimated using the Laplace's law. Specifically, the estimated burst pressure was higher than the physiological pressures and the estimated compliance was similar or higher than that of native rat aorta and Goretex® prosthesis. Enzymatic in vitro degradation tests demonstrated a decrease of order and crystallinity of the SF outer surface as a consequence of the enzyme activity. The in vitro cytocompatibility of the ES-SF tubes was confirmed by the adhesion and growth of primary porcine smooth muscle cells. The in vivo subcutaneous implant into the rat dorsal tissue indicated that ES-SF matrices caused a mild host reaction. Thus, the results of this investigation, in which comprehensive morphological and mechanical aspects, in vitro degradation and in vitro and in vivo biocompatibility were considered, indicate the potential suitability of these ES-SF tubular matrices as scaffolds for the regeneration of small diameter blood vessels. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Complementary effects of two growth factors in multifunctionalized silk nanofibers for nerve reconstruction.

    Directory of Open Access Journals (Sweden)

    Tony M Dinis

    Full Text Available With the aim of forming bioactive guides for peripheral nerve regeneration, silk fibroin was electrospun to obtain aligned nanofibers. These fibers were functionalized by incorporating Nerve Growth Factor (NGF and Ciliary NeuroTrophic Factor (CNTF during electrospinning. PC12 cells grown on the fibers confirmed the bioavailability and bioactivity of the NGF, which was not significantly released from the fibers. Primary neurons from rat dorsal root ganglia (DRGs were grown on the nanofibers and anchored to the fibers and grew in a directional fashion based on the fiber orientation, and as confirmed by growth cone morphology. These biofunctionalized nanofibers led to a 3-fold increase in neurite length at their contact, which was likely due to the NGF. Glial cell growth, alignment and migration were stimulated by the CNTF in the functionalized nanofibers. Organotypic culture of rat fetal DRGs confirmed the complementary effect of both growth factors in multifunctionalized nanofibers, which allowed glial cell migration, alignment and parallel axonal growth in structures resembling the 'bands of Bungner' found in situ. Graftable multi-channel conduits based on biofunctionalized aligned silk nanofibers were developed as an organized 3D scaffold. Our bioactive silk tubes thus represent new options for a biological and biocompatible nerve guidance conduit.

  5. Evaluation of structural and mechanical properties of electrospun nano-micro hybrid of poly hydroxybutyrate-chitosan/silk scaffold for cartilage tissue engineering.

    Science.gov (United States)

    Karbasi, Saeed; Fekrat, Farnoosh; Semnani, Daryoush; Razavi, Shahnaz; Zargar, Elham Naghash

    2016-01-01

    One of the new methods of scaffold fabrication is a nano-micro hybrid structure in which the properties of the scaffold are improved by introducing nanometer and micrometer structures. This method could be suitable for scaffold designing if some features improve. In this study, electrospun nanofibers of 9% weight solution of poly (3-hydroxybutyrate) (P3HB) and a 15% weight of chitosan by trifluoroacetic acid were coated on both the surface of a silk knitted substrate in the optimum condition to improve the mechanical properties of scaffolds for cartilage tissue engineering application. These hybrid nano-micro fibrous scaffolds were characterized by structural and mechanical evaluation methods. Scanning electron microscopy values and porosity analysis showed that average diameter of nanofibers was 584.94 nm in electrospinning part and general porosity was more than 80%. Fourier transform infrared spectroscopy results indicated the presence of all elements without pollution. The tensile test also stated that by electrospinning, as well as adding chitosan, both maximum strength and maximum elongation increased to 187 N and 10 mm. It means that the microfibrous part of scaffold could affect mechanical properties of nano part of the hybrid scaffold, significantly. It could be concluded that P3HB-chitosan/silk hybrid scaffolds can be a good candidate for cartilage tissue engineering.

  6. Development of novel electrospun nanofibrous scaffold from P. ricini and A. mylitta silk fibroin blend with improved surface and biological properties

    International Nuclear Information System (INIS)

    Panda, N.; Bissoyi, A.; Pramanik, K.; Biswas, A.

    2015-01-01

    Biomaterials that stimulate cell attachment and proliferation without any surface modification (e.g. RGD coating) provide potent and cost effective scaffold for regenerative medicine. This study assessed the physico-chemical properties and cell supportive potential of a silk fibroin blend scaffold derived from eri (Philosamia ricini) and tasar (Antheraea mylitta) silk (ET) respectively by electrospinning process. The scanning electron microscopy and transmission electron microscopy study found that the fiber diameters are in 200 to 800 nm range with flat morphology. The porosity of ET scaffold is found to be 79 ± 5% with majority of pore diameter between 2.5 to 5 nm. Similarly, Bombyx mori (BM) silk fibroin and gelatin nanofibrous scaffolds were prepared and taken as control. The ultimate tensile strength of the ET and BM scaffold are found to be 1.83 ± 0.13 MPa and 1.47 ± 0.10 MPa respectively. The measured contact angle (a measure of hydrophilicity) for ET (54.7° ± 1.8°) is found to be lower than BM (62° ± 2.3°). The ability to deposit apatite over ET is comparable to that of BM nanofibers. All the scaffolds were seeded with cord blood derived mesenchymal stem cells (hMSCs) and cultured for 14 days in vitro. The immunofluorescence study reveals enhanced cell attachment with higher metabolic activity for MSCs grown over ET than BM and gelatin. The ET scaffold also demonstrated expression of higher amount cell adhesion molecules (CD29/CD44) and higher proliferation rate than BM and gelatin as confirmed by MTT assay, DNA content estimation assay, flow cytometry study and SEM study. Overall, it may be concluded that ET scaffold may have potential in developing bone tissue grafts for clinical applications in the future. - Highlights: • We have fabricated eri–tasar blended electrospun silk fibroin nanofiber with superior surface property. • The hydrophilicity is higher than the silk fibroin nanofiber derived from Bombyx mori (BM). • The nanofibrous

  7. Development of novel electrospun nanofibrous scaffold from P. ricini and A. mylitta silk fibroin blend with improved surface and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    Panda, N.; Bissoyi, A.; Pramanik, K.; Biswas, A., E-mail: amitb79@gmail.com

    2015-03-01

    Biomaterials that stimulate cell attachment and proliferation without any surface modification (e.g. RGD coating) provide potent and cost effective scaffold for regenerative medicine. This study assessed the physico-chemical properties and cell supportive potential of a silk fibroin blend scaffold derived from eri (Philosamia ricini) and tasar (Antheraea mylitta) silk (ET) respectively by electrospinning process. The scanning electron microscopy and transmission electron microscopy study found that the fiber diameters are in 200 to 800 nm range with flat morphology. The porosity of ET scaffold is found to be 79 ± 5% with majority of pore diameter between 2.5 to 5 nm. Similarly, Bombyx mori (BM) silk fibroin and gelatin nanofibrous scaffolds were prepared and taken as control. The ultimate tensile strength of the ET and BM scaffold are found to be 1.83 ± 0.13 MPa and 1.47 ± 0.10 MPa respectively. The measured contact angle (a measure of hydrophilicity) for ET (54.7° ± 1.8°) is found to be lower than BM (62° ± 2.3°). The ability to deposit apatite over ET is comparable to that of BM nanofibers. All the scaffolds were seeded with cord blood derived mesenchymal stem cells (hMSCs) and cultured for 14 days in vitro. The immunofluorescence study reveals enhanced cell attachment with higher metabolic activity for MSCs grown over ET than BM and gelatin. The ET scaffold also demonstrated expression of higher amount cell adhesion molecules (CD29/CD44) and higher proliferation rate than BM and gelatin as confirmed by MTT assay, DNA content estimation assay, flow cytometry study and SEM study. Overall, it may be concluded that ET scaffold may have potential in developing bone tissue grafts for clinical applications in the future. - Highlights: • We have fabricated eri–tasar blended electrospun silk fibroin nanofiber with superior surface property. • The hydrophilicity is higher than the silk fibroin nanofiber derived from Bombyx mori (BM). • The nanofibrous

  8. Coaxial electrospun aligned tussah silk fibroin nanostructured fiber scaffolds embedded with hydroxyapatite–tussah silk fibroin nanoparticles for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Weili [Key Laboratory of Advanced Textile Composites, Ministry of Education, Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); He, Jianxin, E-mail: hejianxin771117@163.com [College of Textiles, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); Sang, Feng [Department of Acquired Immune Deficiency Syndrome Treatment and Research Center, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450007 (China); Ding, Bin [College of Textiles, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); Chen, Li, E-mail: chenli@tjpu.edu.cn [Key Laboratory of Advanced Textile Composites, Ministry of Education, Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Cui, Shizhong; Li, Kejing; Han, Qiming; Tan, Weilin [College of Textiles, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China)

    2016-01-01

    The bone is a composite of inorganic and organic materials and possesses a complex hierarchical architecture consisting of mineralized fibrils formed by collagen molecules and coated with oriented hydroxyapatite. To regenerate bone tissue, it is necessary to provide a scaffold that mimics the architecture of the extracellular matrix in native bone. Here, we describe one such scaffold, a nanostructured composite with a core made of a composite of hydroxyapatite and tussah silk fibroin. The core is encased in a shell of tussah silk fibroin. The composite fibers were fabricated by coaxial electrospinning using green water solvent and were characterized using different techniques. In comparison to nanofibers of pure tussah silk, composite notably improved mechanical properties, with 90-fold and 2-fold higher initial modulus and breaking stress, respectively, obtained. Osteoblast-like MG-63 cells were cultivated on the composite to assess its suitability as a scaffold for bone tissue engineering. We found that the fiber scaffold supported cell adhesion and proliferation and functionally promoted alkaline phosphatase and mineral deposition relevant for biomineralization. In addition, the composite were more biocompatible than pure tussah silk fibroin or cover slip. Thus, the nanostructured composite has excellent biomimetic and mechanical properties and is a potential biocompatible scaffold for bone tissue engineering. - Highlights: • A designing scaffold strategy to imitate the mineralized collagen bundles in natural bone was presented. • Aligned nanostructured composite fibers were fabricated by coaxial electrospinning using green water solvent. • Mechanical properties of aligned TSF nanofiber had been significantly improved by embedding with composite nanoparticles. • Composite scaffolds effectively supported proliferation of MG-63 cells and promoted biomineralization.

  9. Biofunctionalized Nanofibers Using Arthrospira (Spirulina Biomass and Biopolymer

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2015-01-01

    Full Text Available Electrospun nanofibers composed of polymers have been extensively researched because of their scientific and technical applications. Commercially available polyhydroxybutyrate (PHB and polyhydroxybutyrate-co-valerate (PHB-HV copolymers are good choices for such nanofibers. We used a highly integrated method, by adjusting the properties of the spinning solutions, where the cyanophyte Arthrospira (formally Spirulina was the single source for nanofiber biofunctionalization. We investigated nanofibers using PHB extracted from Spirulina and the bacteria Cupriavidus necator and compared the nanofibers to those made from commercially available PHB and PHB-HV. Our study assessed nanofiber formation and their selected thermal, mechanical, and optical properties. We found that nanofibers produced from Spirulina PHB and biofunctionalized with Spirulina biomass exhibited properties which were equal to or better than nanofibers made with commercially available PHB or PHB-HV. Our methodology is highly promising for nanofiber production and biofunctionalization and can be used in many industrial and life science applications.

  10. Electrospun silk fibroin/poly (L-lactide-ε-caplacton) graft with platelet-rich growth factor for inducing smooth muscle cell growth and infiltration.

    Science.gov (United States)

    Yin, Anlin; Bowlin, Gary L; Luo, Rifang; Zhang, Xingdong; Wang, Yunbing; Mo, Xiumei

    2016-12-01

    The construction of a smooth muscle layer for blood vessel through electrospinning method plays a key role in vascular tissue engineering. However, smooth muscle cells (SMCs) penetration into the electrospun graft to form a smooth muscle layer is limited due to the dense packing of fibers and lack of inducing factors. In this paper, silk fibroin/poly (L-lactide-ε-caplacton) (SF/PLLA-CL) vascular graft loaded with platelet-rich growth factor (PRGF) was fabricated by electrospinning. The in vitro results showed that SMCs cultured in the graft grew fast, and the incorporation of PRGF could induce deeper SMCs infiltrating compared to the SF/PLLA-CL graft alone. Mechanical properties measurement showed that PRGF-incorporated graft had proper tensile stress, suture retention strength, burst pressure and compliance which could match the demand of native blood vessel. The success in the fabrication of PRGF-incorporated SF/PLLA-CL graft to induce fast SMCs growth and their strong penetration into graft has important application for tissue-engineered blood vessels.

  11. Intermolecular interactions between B. mori silk fibroin and poly(L-lactic acid) in electrospun composite nanofibrous scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Taddei, Paola, E-mail: paola.taddei@unibo.it [Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna (Italy); Tozzi, Silvia [Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna (Italy); Zuccheri, Giampaolo [Dipartimento di Farmacia e Biotecnologie e Centro Interdipartimentale di Ricerca Industriale Scienze della Vita e Tecnologie per la Salute, Università di Bologna, Via Irnerio 48, 40126 Bologna (Italy); Centro S3, Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (Italy); Martinotti, Simona; Ranzato, Elia [Dipartimento di Scienze e Innovazione Tecnologica, DiSIT, Università del Piemonte Orientale, viale Teresa Michel 11, 15121 Alessandria (Italy); Chiono, Valeria; Carmagnola, Irene [Dipartimento di Ingegneria Meccanica e Aerospaziale, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Tsukada, Masuhiro [Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)

    2017-01-01

    In this study, composite nanofibrous scaffolds were obtained by electrospinning a trifluoroacetic acid solution containing B. mori silk fibroin (SF) and poly(L-lactic acid) (PLLA) in a 1:1 weight ratio. SF, PLLA and SF/PLLA nanofibres were prepared with average diameter sizes of 360 ± 90 nm, 470 ± 240 nm and 580 ± 220 nm, respectively, as assessed by SEM analysis. Vibrational and thermal analyses showed that upon blending in the SF/PLLA nanofibres, the crystallisation of PLLA was hindered by the presence of SF, which crystallized preferentially and underwent conformational changes that did not significantly change its prevailing β-sheet structure. The two components were thermodynamically compatible and the intermolecular interactions between them were revealed for the first time. Human keratinocytes were cultured on nanofibres and their viability and proliferation were determined. Preliminary in vitro tests showed that the incorporation of SF into the PLLA component enhanced cell adhesion and proliferation with respect to the unfunctionalised material. SF has been successfully used to modify the biomaterial properties and confirmed to be an efficient bioactive protein to mediate cell-biomaterial interaction. - Highlights: • Composite silk fibroin-poly(L-lactic acid) scaffolds were obtained by electrospinning. • Intermolecular interactions between SF and PLLA were revealed for the first time. • Upon blending, the crystallisation of PLLA was hindered by the presence of SF. • SF crystallized preferentially and maintained its prevailing β-sheet structure. • The incorporation of SF into PLLA enhanced human keratinocytes adhesion and proliferation.

  12. Enhanced bone formation in electrospun poly(L-lactic-co-glycolic acid)–tussah silk fibroin ultrafine nanofiber scaffolds incorporated with graphene oxide

    International Nuclear Information System (INIS)

    Shao, Weili; He, Jianxin; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong; Ding, Bin

    2016-01-01

    To engineer bone tissue, it is necessary to provide a biocompatible, mechanically robust scaffold. In this study, we fabricated an ultrafine nanofiber scaffold by electrospinning a blend of poly(L-lactic-co-glycolic acid), tussah silk fibroin, and graphene oxide (GO) and characterized its morphology, biocompatibility, mechanical properties, and biological activity. The data indicate that incorporation of 10 wt.% tussah silk and 1 wt.% graphene oxide into poly(L-lactic-co-glycolic acid) nanofibers significantly decreased the fiber diameter from 280 to 130 nm. Furthermore, tussah silk and graphene oxide boosted the Young's modulus and tensile strength by nearly 4-fold and 3-fold, respectively, and significantly enhanced adhesion, proliferation in mouse mesenchymal stem cells and functionally promoted biomineralization-relevant alkaline phosphatase (ALP) and mineral deposition. The results indicate that composite nanofibers could be excellent and versatile scaffolds for bone tissue engineering. - Highlights: • GO-doped PLGA–tussah silk fibroin ultrafine nanofibers with diameter of about 130 nm were fabricated by electrospinning. • Incorporation of 10 wt.% tussah silk to the PLGA nanofibers accelerates osteoblast differentiation and formation of new bone. • Mechanical properties of composite nanofiber mats had been significantly improved after embedding with GO nanosheets. • Nanostructured composite scaffolds effectively accelerate mesenchymal stem cells differentiation and formation of new bone.

  13. Enhanced bone formation in electrospun poly(L-lactic-co-glycolic acid)–tussah silk fibroin ultrafine nanofiber scaffolds incorporated with graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Weili [Key Laboratory of Advanced Textile Composites (Ministry of Education), Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); He, Jianxin, E-mail: hejianxin771117@163.com [Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Sang, Feng [Department of Acquired Immune Deficiency Syndrome Treatment and Research Center, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450000 (China); Wang, Qian [Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Chen, Li [Key Laboratory of Advanced Textile Composites (Ministry of Education), Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Cui, Shizhong [Key Laboratory of Advanced Textile Composites (Ministry of Education), Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Ding, Bin [Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201600 (China)

    2016-05-01

    To engineer bone tissue, it is necessary to provide a biocompatible, mechanically robust scaffold. In this study, we fabricated an ultrafine nanofiber scaffold by electrospinning a blend of poly(L-lactic-co-glycolic acid), tussah silk fibroin, and graphene oxide (GO) and characterized its morphology, biocompatibility, mechanical properties, and biological activity. The data indicate that incorporation of 10 wt.% tussah silk and 1 wt.% graphene oxide into poly(L-lactic-co-glycolic acid) nanofibers significantly decreased the fiber diameter from 280 to 130 nm. Furthermore, tussah silk and graphene oxide boosted the Young's modulus and tensile strength by nearly 4-fold and 3-fold, respectively, and significantly enhanced adhesion, proliferation in mouse mesenchymal stem cells and functionally promoted biomineralization-relevant alkaline phosphatase (ALP) and mineral deposition. The results indicate that composite nanofibers could be excellent and versatile scaffolds for bone tissue engineering. - Highlights: • GO-doped PLGA–tussah silk fibroin ultrafine nanofibers with diameter of about 130 nm were fabricated by electrospinning. • Incorporation of 10 wt.% tussah silk to the PLGA nanofibers accelerates osteoblast differentiation and formation of new bone. • Mechanical properties of composite nanofiber mats had been significantly improved after embedding with GO nanosheets. • Nanostructured composite scaffolds effectively accelerate mesenchymal stem cells differentiation and formation of new bone.

  14. Enhanced bone formation in electrospun poly(L-lactic-co-glycolic acid)-tussah silk fibroin ultrafine nanofiber scaffolds incorporated with graphene oxide.

    Science.gov (United States)

    Shao, Weili; He, Jianxin; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong; Ding, Bin

    2016-05-01

    To engineer bone tissue, it is necessary to provide a biocompatible, mechanically robust scaffold. In this study, we fabricated an ultrafine nanofiber scaffold by electrospinning a blend of poly(L-lactic-co-glycolic acid), tussah silk fibroin, and graphene oxide (GO) and characterized its morphology, biocompatibility, mechanical properties, and biological activity. The data indicate that incorporation of 10 wt.% tussah silk and 1 wt.% graphene oxide into poly(L-lactic-co-glycolic acid) nanofibers significantly decreased the fiber diameter from 280 to 130 nm. Furthermore, tussah silk and graphene oxide boosted the Young's modulus and tensile strength by nearly 4-fold and 3-fold, respectively, and significantly enhanced adhesion, proliferation in mouse mesenchymal stem cells and functionally promoted biomineralization-relevant alkaline phosphatase (ALP) and mineral deposition. The results indicate that composite nanofibers could be excellent and versatile scaffolds for bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Biofunctionalization of diamond microelectrodes

    Energy Technology Data Exchange (ETDEWEB)

    Reitinger, Andreas Adam; Lud, Simon Quartus; Stutzmann, Martin; Garrido, Jose Antonio [Walter Schottky Institut, TU Muenchen (Germany); Hutter, Naima Aurelia; Richter, Gerhard; Jordan, Rainer [WACKER-Chair of Macromolecular Chemistry, TU Muenchen (Germany)

    2010-07-01

    In this work we present two main routes for the biofunctionalization of nanocrystalline diamond films, aiming at the application of diamond microelectrodes as amperometric biosensors. We report on direct covalent grafting of biomolecules on nanocrystalline diamond films via diazonium monophenyls and biphenyls as well as other linker molecules, forming self-assembled monolayers on the diamond surface. Monolayers with different functional head groups have been characterized. Patterning of the available functional groups using electron beam-induced chemical lithography allows the selective preparation of well-localized docking sites for the immobilization of biomolecules. Furthermore, polymer brushes are expected to enable novel paths for designing more advanced biosensing schemes, incorporating multifunctional groups and a higher loading capacity for biomolecules. Here, we focus on the preparation of polymer grafts by self-initiated photografting and photopolymerization. Further chemical modification of the grafted polymer brushes results in the introduction of additional functional molecules, paving the way for the incorporation of more complex molecular structures such as proteins. In a comparative study we investigate the advantages and disadvantages of both approaches.

  16. SPIDER SILK

    Directory of Open Access Journals (Sweden)

    PORAV Viorica

    2014-05-01

    Full Text Available The strengthness and toughness of spider fiber and its multifunctional nature is only surpassed in some cases by synthetic high performance fibers. In the world of natural fibers, spider silk has been long time recognized as a wonder fiber for its unique combination of high strength and rupture elongation. Scientists in civil military engineering reveal that the power of biological material (spider silk lies in the geometric configuration of structural protein, and the small cluster of week hydrogen bonds that works together to resist force and dissipate energy. Each spider and each type of silk has a set of mechanical properties optimized for their biological function. Most silks, in particular deagline silk, have exceptional mechanical properties. They exhibit a unique combination of high tensile strength and extensibility (ductility. This enables a silk fiber to absorb a lot of energy before breaking (toughness, the area under a stress- strain curve. A frequent mistake made in the mainstream media is to confuse strength and toughness when comparing silk to other materials. As shown below in detail, weight for weight, silk is stronger than steel, but not as strong as Kevlar. Silk is,however, tougher than both.This paper inform about overview on the today trend in the world of spider silk.

  17. Silk-Silk Interactions between Silkworm Fibroin and Recombinant Spider Silk Fusion Proteins Enable the Construction of Bioactive Materials.

    Science.gov (United States)

    Nilebäck, Linnea; Chouhan, Dimple; Jansson, Ronnie; Widhe, Mona; Mandal, Biman B; Hedhammar, My

    2017-09-20

    Natural silk is easily accessible from silkworms and can be processed into different formats suitable as biomaterials and cell culture matrixes. Recombinant DNA technology enables chemical-free functionalization of partial silk proteins through fusion with peptide motifs and protein domains, but this constitutes a less cost-effective production process. Herein, we show that natural silk fibroin (SF) can be used as a bulk material that can be top-coated with a thin layer of the recombinant spider silk protein 4RepCT in fusion with various bioactive motifs and domains. The coating process is based on a silk assembly to achieve stable interactions between the silk types under mild buffer conditions. The assembly process was studied in real time by quartz crystal microbalance with dissipation. Coatings, electrospun mats, and microporous scaffolds were constructed from Antheraea assama and Bombyx mori SFs. The morphology of the fibroin materials before and after coating with recombinant silk proteins was analyzed by scanning electron microscopy and atomic force microscopy. SF materials coated with various bioactive 4RepCT fusion proteins resulted in directed antibody capture, enzymatic activity, and improved cell attachment and spreading, respectively, compared to pristine SF materials. The herein-described procedure allows a fast and easy route for the construction of bioactive materials.

  18. Effect of Sodium Carbonate Concentrations on the Formation and Mechanism of Regenerated Silk Fibroin Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Hao Dou

    2014-01-01

    Full Text Available Degumming is the first process for the preparation of all silk-based products. In this paper, effect of sodium carbonate concentrations for silk degumming on the formation of electrospun silk fibroin nanofibers was investigated and the reason for the silk electrospinning process was explained for the first time by differences from the microstructure of regenerated silk fibroin. With increasing the sodium carbonate concentration, microstructure both in the aqueous solutions and in the electrospinning solutions transformed from nanofibrils to nanoparticles, leading to obvious changes on rheological property; electrospinning solutions with nanofibrils behaved like the native silk dope and owned remarkably higher viscosity than the solutions with nanoparticles showing very low viscosity. More interestingly, nanofibrils favored the formation of silk nanofibers with ease, and even nanofibers could be electrospun at concentration 2%. However, nanoparticles were completely unable to generate nanofibers at high spinning concentration 8%. Importance of sodium carbonate concentrations is heavily emphasized for impacting the microstructure types and further influencing the electrospinning performance of regenerated silk. Hence, sodium carbonate concentrations provide a controllable choice for the preparation of silk-based electrospun biomaterials with desired properties.

  19. Preparation of collagen/polyurethane/knitted silk as a composite scaffold for tendon tissue engineering.

    Science.gov (United States)

    Sharifi-Aghdam, Maryam; Faridi-Majidi, Reza; Derakhshan, Mohammad Ali; Chegeni, Arash; Azami, Mahmoud

    2017-07-01

    The main objective of this study was to prepare a hybrid three-dimensional scaffold that mimics natural tendon tissues. It has been found that a knitted silk shows good mechanical strength; however, cell growth on the bare silk is not desirable. Hence, electrospun collagen/polyurethane combination was used to cover knitted silk. A series of collagen and polyurethane solutions (4%-7% w/v) in aqueous acetic acid were prepared and electrospun. According to obtained scanning electron microscopy images from pure collagen and polyurethane nanofibers, concentration was set constant at 5% (w/v) for blend solutions of collagen/polyurethane. Afterward, blend solutions with the weight ratios of 75/25, 50/50 and 25/75 were electrospun. Scanning electron microscopy images demonstrated the smooth and uniform morphology for the optimized nanofibers. The least fibers diameter among three weight ratios was found for collagen/polyurethane (25/75) which was 100.86 ± 40 nm and therefore was selected to be electrospun on the knitted silk. Attenuated total reflectance-Fourier transform infrared spectra confirmed the chemical composition of obtained electrospun nanofibers on the knitted silk. Tensile test of the specimens including blend nanofiber, knitted silk and commercial tendon substitute examined and indicated that collagen/polyurethane-coated knitted silk has appropriate mechanical properties as a scaffold for tendon tissue engineering. Then, Alamar Blue assay of the L929 fibroblast cell line seeded on the prepared scaffolds demonstrated appropriate viability of the cells with a significant proliferation on the scaffold containing more collagen content. The results illustrate that the designed structure would be promising for being used as a temporary substitute for tendon repair.

  20. Effect of Na2CO3 degumming concentration on LiBr-formic acid-silk fibroin solution properties

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2016-01-01

    Full Text Available Salt-acid system has been proved to be of high efficiency for silk fibroin dissolution. Using salt-acid system to dissolve silk, native silk fibrils can be preserved in the regenerated solution. Increasing experiments indicate that acquirement of silk fibrils in solution is strongly associated with the degumming process. In this study, the effect of sodium carbonate degumming concentration on solution properties based on lithium bromide-formic acid dissolution system was systematically investigated. Results showed that the morphology transformation of silk fibroin in solution from nanospheres to nanofibrils is determined by sodium carbonate concentration during the degumming process. Solutions containing different silk fibroin structure exhibited different rheological behaviors and different electrospinnability, leading to different electrospun nanofibre properties. The results have guiding significance for preparation and application of silk fibroin solutions.

  1. Hierarchically Structured Electrospun Fibers

    Science.gov (United States)

    2013-01-07

    in the natural lotus and silver ragwort leaves. Figure 4. Examples of electrospun bio-mimics of natural hierarchical structures. (A) Lotus leaf...B) pillared poly(methyl methacrylate) (PMMA) electrospun fiber mimic; (C) silver ragwort leaf; (D) electrospun fiber mimic made from nylon 6 and...domains containing the protein in the surrounding EVA fibers [115]. A wide variety of core-shell fibers have been generated, including PCL/ gelatin

  2. Transgenic Silk Moths to Produce Spider Silk

    National Research Council Canada - National Science Library

    Herrera, Rene J

    2008-01-01

    .... Other alternatives like production of the protein that yields same or similar mechanical properties of dragline silk in microorganisms or mammalian cells, in spinning fibers from concentrated protein...

  3. Biomechanics of Spider Silks

    Science.gov (United States)

    2006-03-02

    water and deformation conditions. Such fibres [Nexia ’ biosteel ’ silk ] were spun from recombinant silk ’cloned’ from Spidroin II and indeed show 67...SUBTITLE 5. FUNDING NUMBERS Biomechanics of Spider Silks F49620-03-1-0111 6. AUTHOR(S) Fritz Vollrath 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Perform Pro, WHSIDIOR, Oct 94 COVER SHEET FINAL (3rd Year) Report to AFOSR on: BIOMECHANICS OF SPIDER SILKS Fritz Vollrath, Oxford University, England

  4. Radiation degradation of silk

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Kazushige; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Silk fibroin powder was prepared from irradiated silk fibroin fiber by means of only physical treatment. Silk fibroin fiber irradiated with an accelerated electron beam in the dose range of 250 - 1000 kGy was pulverized by using a ball mill. Unirradiated silk fibroin fiber was not pulverized at all. But the more irradiation was increased, the more the conversion efficiency from fiber to powder was increased. The conversion efficiency of silk fibroin fiber irradiated 1000 kGy in oxygen was 94%. Silk fibroin powder shows remarkable solubility, which dissolved 57% into water of ambient temperature. It is a very interesting phenomenon that silk fibroin which did not treat with chemicals gets solubility only being pulverized. In order to study mechanism of solubilization of silk fibroin powder, amino acid component of soluble part of silk fibroin powder was analyzed. The more irradiation dose up, the more glycine or alanine degraded, but degradation fraction reached bounds about 50%. Other amino acids were degraded only 20% even at the maximum. To consider crystal construction of silk fibroin, it is suggested that irradiation on silk fibroin fiber selectively degrades glycine and alanine in amorphous region, which makes it possible to pulverize and to dissolve silk fibroin powder. (author)

  5. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    International Nuclear Information System (INIS)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-01-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds

  6. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Mirahmadi, Fereshteh [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Tafazzoli-Shadpour, Mohammad, E-mail: Tafazoli@aut.ac.ir [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali, E-mail: mashokrgozar@pasteur.ac.ir [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Bonakdar, Shahin [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds.

  7. Role of chondroitin sulphate tethered silk scaffold in cartilaginous disc tissue regeneration.

    Science.gov (United States)

    Bhattacharjee, Maumita; Chawla, Shikha; Chameettachal, Shibu; Murab, Sumit; Bhavesh, Neel Sarovar; Ghosh, Sourabh

    2016-04-12

    Strategies for tissue engineering focus on scaffolds with tunable structure and morphology as well as optimum surface chemistry to simulate the anatomy and functionality of the target tissue. Silk fibroin has demonstrated its potential in supporting cartilaginous tissue formation both in vitro and in vivo. In this study, we investigate the role of controlled lamellar organization and chemical composition of biofunctionalized silk scaffolds in replicating the structural properties of the annulus region of an intervertebral disc using articular chondrocytes. Covalent attachment of chondroitin sulfate (CS) to silk is characterized. CS-conjugated silk constructs demonstrate enhanced cellular metabolic activity and chondrogenic redifferentiation potential with significantly improved mechanical properties over silk-only constructs. A matrix-assisted laser desorption ionization-time of flight analysis and protein-protein interaction studies help to generate insights into how CS conjugation can facilitate the production of disc associated matrix proteins, compared to a silk-only based construct. An in-depth understanding of the interplay between such extra cellular matrix associated proteins should help in designing more rational scaffolds for cartilaginous disc regeneration needs.

  8. Role of chondroitin sulphate tethered silk scaffold in cartilaginous disc tissue regeneration

    International Nuclear Information System (INIS)

    Bhattacharjee, Maumita; Chawla, Shikha; Chameettachal, Shibu; Murab, Sumit; Ghosh, Sourabh; Bhavesh, Neel Sarovar

    2016-01-01

    Strategies for tissue engineering focus on scaffolds with tunable structure and morphology as well as optimum surface chemistry to simulate the anatomy and functionality of the target tissue. Silk fibroin has demonstrated its potential in supporting cartilaginous tissue formation both in vitro and in vivo. In this study, we investigate the role of controlled lamellar organization and chemical composition of biofunctionalized silk scaffolds in replicating the structural properties of the annulus region of an intervertebral disc using articular chondrocytes. Covalent attachment of chondroitin sulfate (CS) to silk is characterized. CS-conjugated silk constructs demonstrate enhanced cellular metabolic activity and chondrogenic redifferentiation potential with significantly improved mechanical properties over silk-only constructs. A matrix-assisted laser desorption ionization-time of flight analysis and protein–protein interaction studies help to generate insights into how CS conjugation can facilitate the production of disc associated matrix proteins, compared to a silk-only based construct. An in-depth understanding of the interplay between such extra cellular matrix associated proteins should help in designing more rational scaffolds for cartilaginous disc regeneration needs. (paper)

  9. New application of silk protein

    International Nuclear Information System (INIS)

    Kamiishi, Youichi

    2000-01-01

    Gunma prefecture is famous for sericulture and silk textile industry district in Japan. In Gunma prefecture, some kinds of new generation silk as high performance and high quality silk were developed. These silk are used not only for the new textile materials but also for new industrial materials. New application of silk protein, fibroin and sericin, is considered. (author)

  10. New application of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan)

    2000-03-01

    Gunma prefecture is famous for sericulture and silk textile industry district in Japan. In Gunma prefecture, some kinds of new generation silk as high performance and high quality silk were developed. These silk are used not only for the new textile materials but also for new industrial materials. New application of silk protein, fibroin and sericin, is considered. (author)

  11. Comparative Study of Silk-Silk Alloy Materials

    Science.gov (United States)

    Xue, Ye; Jao, Dave; Hu, Wenbing; Wolf, Nathan; Rocks, Eva-Marie; Hu, Xiao

    Silk fibroin materials can be used for various kinds of biomedical applications. We report a comparative study of silk-silk blend materials using thermal analysis and infrared spectroscopy. Four groups of silk-silk blend films: Mori-Tussah, Mori-Muga, Mori-Eri and Mori-Thai, were fabricated from aqueous solutions and blended at different weight ratios, respectively. These silk-silk blend systems exploit the beneficial material properties of both silks. DSC and temperature-modulated DSC were used to measure the transition temperatures and heat capacity of these water-based silk-silk blend films. Fourier transform infrared spectrometer was used to characterize secondary structures of silk-silk blends. This study demonstrates that Mori silk are fully miscible with Tussah, Muga, Eri and Thai silk at different weight ratios without phase separation. Glass transition temperatures, degradation temperatures and the contents of alpha-helix and random coils of those silk-silk blend films can be controlled by changing the contents of different silks in the blend system. The features of Mori silk combined with the attributes of Tussah, Muga, Eri and Thai silk offer a useful suite of materials for a variety of applications in the future.

  12. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering.

    Science.gov (United States)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber-hydrogel composite for GAG content and in two-layer electrospun fiber-hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. © 2013.

  13. Water-insoluble Silk Films with Silk I Structure

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Q.; Hu, X; Wang, X; Kluge, J; Lu, S; Cebe, P; Kaplan, D

    2010-01-01

    Water-insoluble regenerated silk materials are normally produced by increasing the {beta}-sheet content (silk II). In the present study water-insoluble silk films were prepared by controlling the very slow drying of Bombyx mori silk solutions, resulting in the formation of stable films with a predominant silk I instead of silk II structure. Wide angle X-ray scattering indicated that the silk films stabilized by slow drying were mainly composed of silk I rather than silk II, while water- and methanol-annealed silk films had a higher silk II content. The silk films prepared by slow drying had a globule-like structure at the core surrounded by nano-filaments. The core region was composed of silk I and silk II, surrounded by hydrophilic nano-filaments containing random turns and {alpha}-helix secondary structures. The insoluble silk films prepared by slow drying had unique thermal, mechanical and degradative properties. Differential scanning calorimetry results revealed that silk I crystals had stable thermal properties up to 250 C, without crystallization above the T{sub g}, but degraded at lower temperatures than silk II structure. Compared with water- and methanol-annealed films the films prepared by slow drying had better mechanical ductility and were more rapidly enzymatically degraded, reflecting the differences in secondary structure achieved via differences in post processing of the cast silk films. Importantly, the silk I structure, a key intermediate secondary structure for the formation of mechanically robust natural silk fibers, was successfully generated by the present approach of very slow drying, mimicking the natural process. The results also point to a new mode of generating new types of silk biomaterials with enhanced mechanical properties and increased degradation rates, while maintaining water insolubility, along with a low {beta}-sheet content.

  14. DNA preservation in silk.

    Science.gov (United States)

    Liu, Yawen; Zheng, Zhaozhu; Gong, He; Liu, Meng; Guo, Shaozhe; Li, Gang; Wang, Xiaoqin; Kaplan, David L

    2017-06-27

    The structure of DNA is susceptible to alterations at high temperature and on changing pH, irradiation and exposure to DNase. Options to protect and preserve DNA during storage are important for applications in genetic diagnosis, identity authentication, drug development and bioresearch. In the present study, the stability of total DNA purified from human dermal fibroblast cells, as well as that of plasmid DNA, was studied in silk protein materials. The DNA/silk mixtures were stabilized on filter paper (silk/DNA + filter) or filter paper pre-coated with silk and treated with methanol (silk/DNA + PT-filter) as a route to practical utility. After air-drying and water extraction, 50-70% of the DNA and silk could be retrieved and showed a single band on electrophoretic gels. 6% silk/DNA + PT-filter samples provided improved stability in comparison with 3% silk/DNA + filter samples and DNA + filter samples for DNA preservation, with ∼40% of the band intensity remaining at 37 °C after 40 days and ∼10% after exposure to UV light for 10 hours. Quantitative analysis using the PicoGreen assay confirmed the results. The use of Tris/borate/EDTA (TBE) buffer enhanced the preservation and/or extraction of the DNA. The DNA extracted after storage maintained integrity and function based on serving as a functional template for PCR amplification of the gene for zinc finger protein 750 (ZNF750) and for transgene expression of red fluorescence protein (dsRed) in HEK293 cells. The high molecular weight and high content of a crystalline beta-sheet structure formed on the coated surfaces likely accounted for the preservation effects observed for the silk/DNA + PT-filter samples. Although similar preservation effects were also obtained for lyophilized silk/DNA samples, the rapid and simple processing available with the silk-DNA-filter membrane system makes it appealing for future applications.

  15. Isolation of cancer cells by "in situ" microfluidic biofunctionalization protocols

    DEFF Research Database (Denmark)

    De Vitis, Stefania; Matarise, Giuseppina; Pardeo, Francesca

    2014-01-01

    The aim of this work is the development of a microfluidic immunosensor for the immobilization of cancer cells and their separation from healthy cells by using "in situ" microfluidic biofunctionalization protocols. These protocols allow to link antibodies on microfluidic device surfaces and can be...

  16. Chemical stabilization of porous silicon for enhanced biofunctionalization with immunoglobulin

    Directory of Open Access Journals (Sweden)

    Nelson Naveas, Vicente Torres Costa, Dario Gallach, Jacobo Hernandez-Montelongo, Raul Jose Martín Palma, Josefa Predenstinacion Garcia-Ruiz and Miguel Manso-Silván

    2012-01-01

    Full Text Available Porous silicon (PSi is widely used in biological experiments, owing to its biocompatibility and well-established fabrication methods that allow tailoring its surface. Nevertheless, there are some unresolved issues such as deciding whether the stabilization of PSi is necessary for its biological applications and evaluating the effects of PSi stabilization on the surface biofunctionalization with proteins. In this work we demonstrate that non-stabilized PSi is prone to detachment owing to the stress induced upon biomolecular adsorption. Biofunctionalized non-stabilized PSi loses the interference properties characteristic of a thin film, and groove-like structures resulting from a final layer collapse were observed by scanning electron microscopy. Likewise, direct PSi derivatization with 3-aminopropyl-triethoxysilane (APTS does not stabilize PSi against immunoglobulin biofunctionalization. To overcome this problem, we developed a simple chemical process of stabilizing PSi (CoxPSi for biological applications, which has several advantages over thermal stabilization (ToxPSi. The process consists of chemical oxidation in H2O2, surface derivatization with APTS and a curing step at 120 °C. This process offers integral homogeneous PSi morphology, hydrophilic surface termination (contact angle θ = 26° and highly efficient derivatized and biofunctionalized PSi surfaces (six times more efficient than ToxPSi. All these features are highly desirable for biological applications, such as biosensing, where our results can be used for the design and optimization of the biomolecular immobilization cascade on PSi surfaces.

  17. Silk-based biomaterials.

    Science.gov (United States)

    Altman, Gregory H; Diaz, Frank; Jakuba, Caroline; Calabro, Tara; Horan, Rebecca L; Chen, Jingsong; Lu, Helen; Richmond, John; Kaplan, David L

    2003-02-01

    Silk from the silkworm, Bombyx mori, has been used as biomedical suture material for centuries. The unique mechanical properties of these fibers provided important clinical repair options for many applications. During the past 20 years, some biocompatibility problems have been reported for silkworm silk; however, contamination from residual sericin (glue-like proteins) was the likely cause. More recent studies with well-defined silkworm silk fibers and films suggest that the core silk fibroin fibers exhibit comparable biocompatibility in vitro and in vivo with other commonly used biomaterials such as polylactic acid and collagen. Furthermore, the unique mechanical properties of the silk fibers, the diversity of side chain chemistries for 'decoration' with growth and adhesion factors, and the ability to genetically tailor the protein provide additional rationale for the exploration of this family of fibrous proteins for biomaterial applications. For example, in designing scaffolds for tissue engineering these properties are particularly relevant and recent results with bone and ligament formation in vitro support the potential role for this biomaterial in future applications. To date, studies with silks to address biomaterial and matrix scaffold needs have focused on silkworm silk. With the diversity of silk-like fibrous proteins from spiders and insects, a range of native or bioengineered variants can be expected for application to a diverse set of clinical needs.

  18. Isolation of cancer cells by "in situ" microfluidic biofunctionalization protocols

    KAUST Repository

    De Vitis, Stefania; Matarise, Giuseppina; Pardeo, Francesca; Catalano, Rossella; Malara, Natalia Maria; Trunzo, Valentina; Tallerico, Rossana; Gentile, Francesco T.; Candeloro, Patrizio; Coluccio, Maria Laura; Massaro, Alessandro S.; Viglietto, Giuseppe; Carbone, Ennio; Kutter, Jö rg Peter; Perozziello, Gerardo; Di Fabrizio, Enzo M.

    2014-01-01

    The aim of this work is the development of a microfluidic immunosensor for the immobilization of cancer cells and their separation from healthy cells by using "in situ" microfluidic biofunctionalization protocols. These protocols allow to link antibodies on microfluidic device surfaces and can be used to study the interaction between cell membrane and biomolecules. Moreover they allow to perform analysis with high processing speed, small quantity of reagents and samples, short reaction times and low production costs. In this work the developed protocols were used in microfluidic devices for the isolation of cancer cells in heterogeneous blood samples by exploiting the binding of specific antibody to an adhesion protein (EpCAM), overexpressed on the tumor cell membranes. The presented biofunctionalization protocols can be performed right before running the experiment: this allows to have a flexible platform where biomolecules of interest can be linked on the device surface according to the user's needs. © 2014 Elsevier B.V. All rights reserved.

  19. Electrospun complexes - functionalised nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, T.; Wolf, M.; Dreyer, B.; Unruh, D.; Krüger, C.; Menze, M. [Leibniz University Hannover, Institute of Inorganic Chemistry (Germany); Sindelar, R. [University of Applied Science Hannover, Faculty II (Germany); Klingelhöfer, G. [Gutenberg-University, Institute of Inorganic and Analytic Chemistry (Germany); Renz, F., E-mail: renz@acd.uni-hannover.de [Leibniz University Hannover, Institute of Inorganic Chemistry (Germany)

    2016-12-15

    Here we present a new approach of using iron-complexes in electro-spun fibres. We modify poly(methyl methacrylate) (PMMA) by replacing the methoxy group with Diaminopropane or Ethylenediamine. The complex is bound covalently via an imine-bridge or an amide. The resulting polymer can be used in the electrospinning process without any further modifications in method either as pure reagent or mixed with small amounts of not functionalised polymer resulting in fibres of different qualities (Fig. 1).

  20. Enhancing analysis of cells and proteins by fluorescence imaging on silk-based biomaterials: modulating the autofluorescence of silk.

    Science.gov (United States)

    Neo, Puay Yong; Tan, Daryl Jian-An; Shi, Pujiang; Toh, Siew Lok; Goh, James Cho-Hong

    2015-02-01

    Silk is a versatile and established biomaterial for various tissue engineering purposes. However, it also exhibits strong autofluorescence signals-thereby hindering fluorescence imaging analysis of cells and proteins on silk-derived biomaterials. Sudan Black B (SB) is a lysochrome dye commonly used to stain lipids in histology. It has also been reported to be able to quench autofluorescence of tissues in histology and has been tested on artificial biomedical polymers in recent years. It was hypothesized that SB would exert similar quenching effects on silk, modulating the autofluorescence signals, and thereby enabling improved imaging analysis of cells and molecules of interests. The quenching effect of SB on the intrinsic fluorescence properties of silk and on commercial fluorescent dyes were first investigated in this study. SB was then incorporated into typical fluorescence-based staining protocols to study its effectiveness in improving fluorescence-based imaging of the cells and proteins residing with the silk-based biomaterials. Silk processed into various forms of biomaterials (e.g., films, sponges, fibers, and electrospun mats) was seeded with cells and cultured in vitro. At sacrificial time points, specimens were harvested, fixed, and prepared for fluorescence staining. SB, available commercially as a powder, was dissolved in 70% ethanol (0.3% [w/v]) to form staining solutions. SB treatment was introduced at the last step of typical immunofluorescence staining protocols for 15-120 min. For actin staining protocols by phalloidin toxin, SB staining solutions were added before and after permeabilization with Triton-X for 15-30 min. Results showed that ideal SB treatment duration is about 15 min. Apart from being able to suppress the autofluorescence of silk, this treatment duration was also not too long to adversely affect the fluorescent labeling probes used. The relative improvement brought about by SB treatment was most evident in the blue and green

  1. Silk I and Silk II studied by fast scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cebe, Peggy; Partlow, Benjamin P.; Kaplan, David L.; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    2017-06-01

    Using fast scanning calorimetry (FSC), we investigated the glass transition and crystal melting of samples of B. mori silk fibroin containing Silk I and/or Silk II crystals. Due to the very short residence times at high temperatures during such measurements, thermal decomposition of silk protein can be significantly suppressed. FSC was performed at 2000 K/s using the Mettler Flash DSC1 on fibroin films with masses around 130–270 ng. Films were prepared with different crystalline fractions (ranging from 0.26 to 0.50) and with different crystal structures (Silk I, Silk II, or mixed) by varying the processing conditions. These included water annealing at different temperatures, exposure to 50% MeOH in water, or autoclaving. The resulting crystal structure was examined using wide angle X-ray scattering. Degree of crystallinity was evaluated from Fourier transform infrared (FTIR) spectroscopy and from analysis of the heat capacity increment at the glass transition temperature. Silk fibroin films prepared by water annealing at 25 °C were the least crystalline and had Silk I structure. FTIR and FSC studies showed that films prepared by autoclaving or 50% MeOH exposure were the most crystalline and had Silk II structure. Intermediate crystalline fraction and mixed Silk I/Silk II structures were found in films prepared by water annealing at 37 °C. FSC results indicate that Silk II crystals exhibit endotherms of narrower width and have higher mean melting temperature Tm(II) = 351 ± 2.6 °C, compared to Silk I crystals which melt at Tm(I) = 292 ± 3.8 °C. Films containing mixed Silk I/Silk II structure showed two clearly separated endothermic peaks. Evidence suggests that the two types of crystals melt separately and do not thermally interconvert on the extremely short time scale (0.065 s between onset and end of melting) of the FSC experiment.

  2. Coating of Silk Fabric Using PVA/Ciprofloxacin Hcl Nanofibers for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Somaye Baghersad

    2016-05-01

    Full Text Available In recent years, fabrication of polymeric antibacterial wound dressing has gained most attention in controlling wound infections. Silk is also a member of the broad family of protein-based polmers. The silk produced by the lepidopteran insect Bombyx mori is a highly accepted material due to its long history as a very valuable textile fiber. Recently, additional applications have been developed for silk, mainly in the field of biotechnology. Regarding its importance in wound healing, silk fabric was incorporated with ciprofloxacin, as an antibiotic, on its surface coated with electro-spun PVA/ciprofloxacin nanofibers. Before coating, degumming was carried out using autoclave technique and properties of the silk fabric, before and after degumming process, was investigated by SEM, FTIR, mechanical properties and moisture absorbance measurement. The results of all analyses showed a reduction in fibers diameter, mechanical strength and moisture absorption after degumming process. Electrospinning condition was optimized and diameter of the nanofibers, with and without drug, was measured before coating. The results showed that addition of the drug increased electrical conductivity of electrospinning solution and resulted in finer nanofibers. Antibacterial test was performed using "disk diffusion method" with Escherichia coli (EC and Staphylococcus aureus (SA bacteria to compare the antibacterial properties of degummed and non-degummed silk fabrics alone and coated with nanofibers. Measurement of bacterial inhibition zone diameter showed no antibacterial activity for degummed and non-degummed silk fabrics alone. However, the sample coated with PVA/ciprofloxacin showed antibacterial activity. The antibacterial property for SA in both cases was the same, but for EC, the antibacterial activity of degummed silk fabric was more than that of non-degummed material.

  3. Silk Electrogel Rheology

    Science.gov (United States)

    Tabatabai, A. P.; Urbach, J. S.; Blair, D. L.; Kaplan, D. L.

    2014-03-01

    We present experimental results on the rheology on electrogels derived from aqueous solutions of reconstituted Bombyx Mori silk fibroin protein. Through electrochemistry, the silk protein solution develops local pH changes resulting in the assembly of protein into a weak gel. We determine the physical properties of the electrogels by performing rheology and observe that they exhibit the characteristics of a crosslinked biopolymer network. Interestingly, we find that these silk gels exhibit linear elasticity over a range of up to two orders of magnitude larger than most crosslinked biopolymer networks. Moreover, the nonlinear rheology exhibits a strain-stiffening behavior that is fundamentally different than the strain-stiffening observed in crosslinked biopolymers. Through rheological techniques we aim to understand this distinctive material that cannot be explained by current polymeric models. This work is supported by a grant from the AFOSR FA9550-07-1-0130.

  4. Biofunctionalization of zinc oxide nanowires for DNA sensory applications

    Directory of Open Access Journals (Sweden)

    Rudolph Bettina

    2011-01-01

    Full Text Available Abstract We report on the biofunctionalization of zinc oxide nanowires for the attachment of DNA target molecules on the nanowire surface. With the organosilane glycidyloxypropyltrimethoxysilane acting as a bifunctional linker, amino-modified capture molecule oligonucleotides have been immobilized on the nanowire surface. The dye-marked DNA molecules were detected via fluorescence microscopy, and our results reveal a successful attachment of DNA capture molecules onto the nanowire surface. The electrical field effect induced by the negatively charged attached DNA molecules should be able to control the electrical properties of the nanowires and gives way to a ZnO nanowire-based biosensing device.

  5. Hierarchically Structured Electrospun Fibers

    Directory of Open Access Journals (Sweden)

    Nicole E. Zander

    2013-01-01

    Full Text Available Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber diameter, porosity and collector geometry will be briefly discussed, as will more traditional methods for controlling fiber morphology and fiber mat architecture. The remainder of the review will focus on new techniques to prepare hierarchically structured fibers. Fibers with hierarchical primary structures—including helical, buckled, and beads-on-a-string fibers, as well as fibers with secondary structures, such as nanopores, nanopillars, nanorods, and internally structured fibers and their applications—will be discussed. These new materials with helical/buckled morphology are expected to possess unique optical and mechanical properties with possible applications for negative refractive index materials, highly stretchable/high-tensile-strength materials, and components in microelectromechanical devices. Core-shell type fibers enable a much wider variety of materials to be electrospun and are expected to be widely applied in the sensing, drug delivery/controlled release fields, and in the encapsulation of live cells for biological applications. Materials with a hierarchical secondary structure are expected to provide new superhydrophobic and self-cleaning materials.

  6. Electrospun Fibers for Composites Applications

    Science.gov (United States)

    2014-02-01

    in traditional woven mat composites. Nanofibrous interlayers were used to increase the impact and shear performance of a prepregged carbon fiber...Nylon 66 Nanofibrilmat Interleaved Carbon/Epoxy Laminates . Polymer Composites 2011, 32, 1781–1789. 21 13. Chen, Q.; Zhang, L.; Rahman, A.; Zhou...Resistance in Laminated Composites With Electrospun Nano-Interlayers. Comp. Sci. Tech. 2008, 68, 673– 683. 15. Zhang, J.; Lin, T.; Wang, X. Electrospun

  7. Isolation of cancer cells by "in situ" microfluidic biofunctionalization protocols

    KAUST Repository

    De Vitis, Stefania

    2014-07-01

    The aim of this work is the development of a microfluidic immunosensor for the immobilization of cancer cells and their separation from healthy cells by using "in situ" microfluidic biofunctionalization protocols. These protocols allow to link antibodies on microfluidic device surfaces and can be used to study the interaction between cell membrane and biomolecules. Moreover they allow to perform analysis with high processing speed, small quantity of reagents and samples, short reaction times and low production costs. In this work the developed protocols were used in microfluidic devices for the isolation of cancer cells in heterogeneous blood samples by exploiting the binding of specific antibody to an adhesion protein (EpCAM), overexpressed on the tumor cell membranes. The presented biofunctionalization protocols can be performed right before running the experiment: this allows to have a flexible platform where biomolecules of interest can be linked on the device surface according to the user\\'s needs. © 2014 Elsevier B.V. All rights reserved.

  8. Regeneration of Bombyx mori silk nanofibers and nanocomposite fibrils by the electrospinning process

    Science.gov (United States)

    Ayutsede, Jonathan Eyitouyo

    In recent years, there has been significant interest in the utilization of natural materials for novel nanoproducts such as tissue engineered scaffolds. Silkworm silk fibers represent one of the strongest natural fibers known. Silkworm silk, a protein-based natural biopolymer, has received renewed interest in recent years due to its unique properties (strength, toughness) and potential applications such as smart textiles, protective clothing and tissue engineering. The traditional 10--20 mum diameter, triangular-shaped Bombyx mori fibers have remained unchanged over the years. However, in our study, we examine the scientific implication and potential applications of reducing the diameter to the nanoscale, changing the triangular shape of the fiber and adding nanofillers in the form of single wall carbon nanotubes (SWNT) by the electrospinning process. The electrospinning process preserves the natural conformation of the silk (random and beta-sheet). The feasibility of changing the properties of the electrospun nanofibers by post processing treatments (annealing and chemical treatment) was investigated. B. mori silk fibroin solution (formic acid) was successfully electrospun to produce uniform nanofibers (as small as 12 nm). Response Surface Methodology (RSM) was applied for the first time to experimental results of electrospinning, to develop a processing window that can reproduce regenerated silk nanofibers of a predictable size (d silk multifunctional nanocomposite fibers were fabricated for the first time with anticipated properties (mechanical, thermal and electrically conductive) that may have scientific applications (nerve regeneration, stimulation of cell-scaffold interaction). In order to realize these applications, the following areas need to be addressed: a systematic investigation of the dispersion of the nanotubes in the silk matrix, a determination of new methodologies for characterizing the nanofiber properties and establishing the nature of the silk

  9. Structural Origins of Silk Piezoelectricity.

    Science.gov (United States)

    Yucel, Tuna; Cebe, Peggy; Kaplan, David L

    2011-02-22

    Uniaxially oriented, piezoelectric silk films were prepared by a two-step method that involved: (1) air drying aqueous, regenerated silk fibroin solutions into films, and (2) drawing the silk films to a desired draw ratio. The utility of two different drawing techniques, zone drawing and water immersion drawing were investigated for processing the silk for piezoelectric studies. Silk films zone drawn to a ratio of λ= 2.7 displayed relatively high dynamic shear piezoelectric coefficients of d(14) = -1.5 pC/N, corresponding to over two orders of magnitude increase in d(14) due to film drawing. A strong correlation was observed between the increase in the silk II, β-sheet content with increasing draw ratio measured by FTIR spectroscopy (C(β)∝ e(2.5) (λ)), the concomitant increasing degree of orientation of β-sheet crystals detected via WAXD (FWHM = 0.22° for λ= 2.7), and the improvement in silk piezoelectricity (d(14)∝ e(2.4) (λ)). Water immersion drawing led to a predominantly silk I structure with a low degree of orientation (FWHM = 75°) and a much weaker piezoelectric response compared to zone drawing. Similarly, increasing the β-sheet crystallinity without inducing crystal alignment, e.g. by methanol treatment, did not result in a significant enhancement of silk piezoelectricity. Overall, a combination of a high degree of silk II, β-sheet crystallinity and crystalline orientation are prerequisites for a strong piezoelectric effect in silk. Further understanding of the structural origins of silk piezoelectricity will provide important options for future biotechnological and biomedical applications of this protein.

  10. A hybrid approach to the surface biofunctionalization of nanostructured porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Silvan, Miguel Manso; Ruiz, Josefa Predestinacion Garcia [Departamento de Fisica Aplicada y Departamento de Biologia Molecular, Facultad de Ciencias, Universidad Autonoma de Madrid, Unidad Asociada GMNF (ICMM-CSIC), 28049 Madrid (Spain); Centro de Investigaciones Biomedicas en Red, Bioingenieria Biomateriales y Nanomedicina (CIBERbbn) (Spain); Gonzalez, Ruy Sanz [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, 28049 Madrid (Spain); Velez, Manuel Hernandez [Departamento de Fisica Aplicada y Departamento de Biologia Molecular, Facultad de Ciencias, Universidad Autonoma de Madrid, Unidad Asociada GMNF (ICMM-CSIC), 28049 Madrid (Spain)

    2010-02-15

    The application of nanostructured porous alumina templates as a solid support in biomedical assays requires a surface biofunctionalization process that has been addressed in this work by an hybrid aminopropyl-triethoxysilane/tetraisopropyl-orthotitanate (APTS/ TIPT) self assembled film. The nanostructured porous alumina templates are activated in a peroxide solution before immersion in the biofunctionalizing APTS/TIPT solution. The biofunctionalization process was followed up by UV-vis spectroscopy, which confirmed the modification of the dielectric structure of the alumina surface. The influence of the biofunctionalization step in an immunological assay was carried out by fluorescence microscopy. Results confirm the gain in activity after the immobilization of an FITC labelled mouse Igg. Specific biological recognition in a bovine serum albumin (BSA)-antiBSA assay is proved afterwards by shifts observed in the reflectance interferograms thus providing a fast biosensing transducer platform. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Silk I and Silk II studied by fast scanning calorimetry.

    Science.gov (United States)

    Cebe, Peggy; Partlow, Benjamin P; Kaplan, David L; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    2017-06-01

    Using fast scanning calorimetry (FSC), we investigated the glass transition and crystal melting of samples of B. mori silk fibroin containing Silk I and/or Silk II crystals. Due to the very short residence times at high temperatures during such measurements, thermal decomposition of silk protein can be significantly suppressed. FSC was performed at 2000K/s using the Mettler Flash DSC1 on fibroin films with masses around 130-270ng. Films were prepared with different crystalline fractions (ranging from 0.26 to 0.50) and with different crystal structures (Silk I, Silk II, or mixed) by varying the processing conditions. These included water annealing at different temperatures, exposure to 50%MeOH in water, or autoclaving. The resulting crystal structure was examined using wide angle X-ray scattering. Degree of crystallinity was evaluated from Fourier transform infrared (FTIR) spectroscopy and from analysis of the heat capacity increment at the glass transition temperature. Silk fibroin films prepared by water annealing at 25°C were the least crystalline and had Silk I structure. FTIR and FSC studies showed that films prepared by autoclaving or 50%MeOH exposure were the most crystalline and had Silk II structure. Intermediate crystalline fraction and mixed Silk I/Silk II structures were found in films prepared by water annealing at 37°C. FSC results indicate that Silk II crystals exhibit endotherms of narrower width and have higher mean melting temperature T m (II)=351±2.6°C, compared to Silk I crystals which melt at T m (I)=292±3.8°C. Films containing mixed Silk I/Silk II structure showed two clearly separated endothermic peaks. Evidence suggests that the two types of crystals melt separately and do not thermally interconvert on the extremely short time scale (0.065s between onset and end of melting) of the FSC experiment. Silkworm silk is a naturally occurring biomaterial. The fibroin component of silk forms two types of crystals. Silk properties depend upon the

  12. Potential anticancer properties of bioactive compounds of Gymnema sylvestre and its biofunctionalized silver nanoparticles.

    Science.gov (United States)

    Arunachalam, Kantha Deivi; Arun, Lilly Baptista; Annamalai, Sathesh Kumar; Arunachalam, Aarrthy M

    2015-01-01

    Gymnema sylvestre is an ethno-pharmacologically important medicinal plant used in many polyherbal formulations for its potential health benefits. Silver nanoparticles (SNPs) were biofunctionalized using aqueous leaf extracts of G. sylvestre. The anticancer properties of the bioactive compounds and the biofunctionalized SNPs were compared using the HT29 human adenoma colon cancer cell line. The preliminary phytochemical screening for bioactive compounds from aqueous extracts revealed the presence of alkaloids, triterpenes, flavonoids, steroids, and saponins. Biofunctionalized SNPs were synthesized using silver nitrate and characterized by ultraviolet-visible spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, and X-ray diffraction for size and shape. The characterized biofunctionalized G. sylvestre were tested for its in vitro anticancer activity against HT29 human colon adenocarcinoma cells. The biofunctionlized G. sylvestre SNPs showed the surface plasmon resonance band at 430 nm. The scanning electron microscopy images showed the presence of spherical nanoparticles of various sizes, which were further determined using the Scherrer equation. In vitro cytotoxic activity of the biofunctionalized green-synthesized SNPs (GSNPs) indicated that the sensitivity of HT29 human colon adenocarcinoma cells for cytotoxic drugs is higher than that of Vero cell line for the same cytotoxic agents and also higher than the bioactive compound of the aqueous extract. Our results show that the anticancer properties of the bioactive compounds of G. sylvestre can be enhanced through biofunctionalizing the SNPs using the bioactive compounds present in the plant extract without compromising their medicinal properties.

  13. Silk Film Embossing System

    Science.gov (United States)

    Paquette, Mark S.

    New tools are often required to facilitate new discoveries and test new methods. Commercial offerings can be prohibitively expensive and difficult to customize. The development of ad-hoc tools provides the most flexibility and provides an opportunity to modify and refine a technology. An embossing system was developed for silk film imprinting and stamping in order to facilitate and add versatility to the efforts involving micro- and nanoscale device manufacturing in biopolymers. This system features temperature controlled embossing surfaces, adjustable embossing pressures, and variable embossing times. The device can also be fitted with interchangeable temperature controlled embossing and stamping tools. The design, development, fabrication, applications, and future improvements are explored for the system. This device may facilitate new discoveries in the realm of biopolymer micro- and nanomanufacturing and may provide a path towards high volume production of silk film based technologies.

  14. Bio-functionalization of conductive textile materials with redox enzymes

    Science.gov (United States)

    Kahoush, M.; Behary, N.; Cayla, A.; Nierstrasz, V.

    2017-10-01

    In recent years, immobilization of oxidoreductase enzymes on electrically conductive materials has played an important role in the development of sustainable bio-technologies. Immobilization process allows the re-use of these bio-catalysts in their final applications. In this study, different methods of immobilizing redox enzymes on conductive textile materials were used to produce bio-functionalized electrodes. These electrodes can be used for bio-processes and bio-sensing in eco-designed applications in domains such as medicine and pollution control. However, the main challenge facing the stability and durability of these electrodes is the maintenance of the enzymatic activity after the immobilization. Hence, preventing the enzyme’s denaturation and leaching is a critical factor for the success of the immobilization processes.

  15. Graphene and graphene oxide: biofunctionalization and applications in biotechnology.

    Science.gov (United States)

    Wang, Ying; Li, Zhaohui; Wang, Jun; Li, Jinghong; Lin, Yuehe

    2011-05-01

    Graphene is the basic building block of 0D fullerene, 1D carbon nanotubes, and 3D graphite. Graphene has a unique planar structure, as well as novel electronic properties, which have attracted great interests from scientists. This review selectively analyzes current advances in the field of graphene bioapplications. In particular, the biofunctionalization of graphene for biological applications, fluorescence-resonance-energy-transfer-based biosensor development by using graphene or graphene-based nanomaterials, and the investigation of graphene or graphene-based nanomaterials for living cell studies are summarized in more detail. Future perspectives and possible challenges in this rapidly developing area are also discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Applicability of biotechnologically produced insect silks.

    Science.gov (United States)

    Herold, Heike M; Scheibel, Thomas

    2017-09-26

    Silks are structural proteins produced by arthropods. Besides the well-known cocoon silk, which is produced by larvae of the silk moth Bombyx mori to undergo metamorphosis inside their silken shelter (and which is also used for textile production by men since millennia), numerous further less known silk-producing animals exist. The ability to produce silk evolved multiple independent times during evolution, and the fact that silk was subject to convergent evolution gave rise to an abundant natural diversity of silk proteins. Silks are used in air, under water, or like honey bee silk in the hydrophobic, waxen environment of the bee hive. The good mechanical properties of insect silk fibres together with their non-toxic, biocompatible, and biodegradable nature renders these materials appealing for both technical and biomedical applications. Although nature provides a great diversity of material properties, the variation in quality inherent in materials from natural sources together with low availability (except from silkworm silk) impeded the development of applications of silks. To overcome these two drawbacks, in recent years, recombinant silks gained more and more interest, as the biotechnological production of silk proteins allows for a scalable production at constant quality. This review summarises recent developments in recombinant silk production as well as technical procedures to process recombinant silk proteins into fibres, films, and hydrogels.

  17. Electrospun amplified fiber optics.

    Science.gov (United States)

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-03-11

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics.

  18. Invited review nonmulberry silk biopolymers.

    Science.gov (United States)

    Kundu, S C; Kundu, Banani; Talukdar, Sarmistha; Bano, Subia; Nayak, Sunita; Kundu, Joydip; Mandal, Biman B; Bhardwaj, Nandana; Botlagunta, Mahendran; Dash, Biraja C; Acharya, Chitrangada; Ghosh, Ananta K

    2012-06-01

    The silk produced by silkworms are biopolymers and can be classified into two types--mulberry and nonmulberry. Mulberry silk of silkworm Bombyx mori has been extensively explored and used for century old textiles and sutures. But for the last few decades it is being extensively exploited for biomedical applications. However, the transformation of nonmulberry silk from being a textile commodity to biomaterials is relatively new. Within a very short period of time, the combination of load bearing capability and tensile strength of nonmulberry silk has been equally envisioned for bone, cartilage, adipose, and other tissue regeneration. Adding to its advantage is its diverse morphology, including macro to nano architectures with controllable degradation and biocompatibility yields novel natural material systems in vitro. Its follow on applications involve sustained release of model compounds and anticancer drugs. Its 3D cancer models provide compatible microenvironment systems for better understanding of the cancer progression mechanism and screening of anticancer compounds. Diversely designed nonmulberry matrices thus provide an array of new cutting age technologies, which is unattainable with the current synthetic materials that lack biodegradability and biocompatibility. Scientific exploration of nonmulberry silk in tissue engineering, regenerative medicine, and biotechnological applications promises advancement of sericulture industries in India and China, largest nonmulberry silk producers of the world. This review discusses the prospective biomedical applications of nonmulberry silk proteins as natural biomaterials. Copyright © 2012 Wiley Periodicals, Inc.

  19. A novel approach to fabricate silk nanofibers containing hydroxyapatite nanoparticles using a three-way stopcock connector

    Science.gov (United States)

    Sheikh, Faheem A.; Ju, Hyung Woo; Moon, Bo Mi; Park, Hyun Jung; Kim, Jung Ho; Lee, Ok Joo; Park, Chan Hum

    2013-07-01

    Electrospinning technique is commonly used to produce micro- and/or nanofibers, which utilizes electrical forces to produce polymeric fibers with diameters ranging from several micrometers down to few nanometers. Desirably, electrospun materials provide highly porous structure and appropriate pore size for initial cell attachment and proliferation and thereby enable the exchange of nutrients. Composite nanofibers consisting of silk and hydroxyapatite nanoparticles (HAp) (NPs) had been considered as an excellent choice due to their efficient biocompatibility and bone-mimicking properties. To prepare these nanofiber composites, it requires the use of acidic solutions which have serious consequences on the nature of both silk and HAp NPs. It is ideal to create these nanofibers using aqueous solutions in which the physicochemical nature of both materials can be retained. However, to create those nanofibers is often difficult to obtain because of the fact that aqueous solutions of silk and HAp NPs can precipitate before they can be ejected into fibers during the electrospinning process. In this work, we had successfully used a three-way stopcock connector to mix the two different solutions, and very shortly, this solution is ejected out to form nanofibers due to electric fields. Different blend ratios consisting HAp NPs had been electrospun into nanofibers. The physicochemical aspects of fabricated nanofiber had been characterized by different state of techniques like that of FE-SEM, EDS, TEM, TEM-EDS, TGA, FT-IR, and XRD. These characterization techniques revealed that HAp NPs can be easily introduced in silk nanofibers using a stopcock connector, and this method favorably preserves the intact nature of silk fibroin and HAp NPs. Moreover, nanofibers obtained by this strategy were tested for cell toxicity and cell attachment studies using NIH 3 T3 fibroblasts which indicated non-toxic behavior and good attachment of cells upon incubation in the presence of nanofibers.

  20. Impact of silk fibroin-based scaffold structures on human osteoblast MG63 cell attachment and proliferation

    Directory of Open Access Journals (Sweden)

    Varkey A

    2015-10-01

    Full Text Available Aneesia Varkey,1,2 Elakkiya Venugopal,2 Ponjanani Sugumaran,2 Gopinathan Janarthanan,1 Mamatha M Pillai,2 Selvakumar Rajendran,2 Amitava Bhattacharyya1 1Advanced Textile and Polymer Research Laboratory, 2Tissue Engineering Laboratory, PSG Institute of Advanced Studies, Coimbatore, Tamil Nadu, India Abstract: The present study was carried out to investigate the impact of various types of silk fibroin (SF scaffolds on human osteoblast-like cell (MG63 attachment and proliferation. SF was isolated from Bombyx mori silk worm cocoons after degumming. Protein concentration in the degummed SF solution was estimated using Bradford method. Aqueous SF solution was used to fabricate three different types of scaffolds, viz, electrospun nanofiber mat, sponge, and porous film. The structures of the prepared scaffolds were characterized using optical micro­scopy and field emission scanning electron microscopy. The changes in the secondary structure of the proteins and the thermal behavior of the scaffolds were determined by Fourier transform infrared spectroscopy and thermo-gravimetric analysis, respectively. The biodegradation rate of scaffolds was determined by incubating the scaffolds in simulated body fluid for 4 weeks. MG63 cells were seeded on the scaffolds and their attachment and proliferation onto the scaffolds were studied. The MTT assay was carried out to deduce the toxicity of the developed scaffolds. All the scaffolds were found to be biocompatible. The amount of collagen produced by the osteoblast-like cells growing on different scaffolds was estimated. Keywords: silk fibroin scaffold, electrospun nanofiber, porous film, sponge, osteoblast

  1. Skin compatibility and antimicrobial studies on biofunctionalized polypropylene fabric

    Energy Technology Data Exchange (ETDEWEB)

    Anjum, Sadiya [Bioengineering Laboratory, Department of Textile Technology, Indian Institute of Technology, New Delhi 110016 (India); Gupta, Amlan; Sharma, Deepika [Department of Pathology, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok 737102 (India); Dalal, Prashansa [Bioengineering Laboratory, Department of Textile Technology, Indian Institute of Technology, New Delhi 110016 (India); Gupta, Bhuvanesh, E-mail: bgupta@textile.iitd.ernet.in [Bioengineering Laboratory, Department of Textile Technology, Indian Institute of Technology, New Delhi 110016 (India)

    2016-12-01

    The aim of this study was the development of antimicrobial fabric which can be used as skin contacting material. The nanosilver loaded bioactive nanogels of polyacrylamide were prepared by gamma irradiation process and the particle size was observed to be in the range of 10–50 nm. In this study, we used polyethylene glycol as carrier for the combination of functional nanogel and essential oils together. Plasma functionalized polypropylene fabric was used as the base material for the bio-immobilization. Bioactive emulsion was coated on the fabric which exhibited excellent antimicrobial activity against Staphylococcus aureus and Escherichia coli. Skin irritation studies were carried out over a period of 3 d on Swiss albino mice. Histopathology studies of the fabric did not show adverse inflammatory response in contact with the skin. The biofunctionalized fabric offers appear to be promising material for skin contacting applications. - Highlights: • Antimicrobial processing of PP fabric for skin contacting material • Polyethylene glycol is used for the carrier of bioactive nanogels. • Synergistic effect of functional nanosilver and essential oil has been investigated. • Skin compatibility and histopathological studies of material have been observed.

  2. Electrospun Borneol-PVP Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Li

    2012-01-01

    Full Text Available The present work investigates the validity of electrospun borneol-polyvinylpyrrolidone (PVP nanocomposites in enhancing drug dissolution rates and improving drug physical stability. Based on hydrogen bonding interactions and via an electrospinning process, borneol and PVP can form stable nanofiber-based composites. FESEM observations demonstrate that composite nanofibers with uniform structure could be generated with a high content of borneol up to 33.3% (w/w. Borneol is well distributed in the PVP matrix molecularly to form the amorphous composites, as verified by DSC and XRD results. The composites can both enhance the dissolution profiles of borneol and increase its physical stability against sublimation for long-time storage by immobilization of borneol molecules with PVP. The incorporation of borneol in the PVP matrix weakens the tensile properties of nanofibers, and the mechanism is discussed. Electrospun nanocomposites can be alternative candidates for developing novel nano-drug delivery systems with high performance.

  3. Optically probing torsional superelasticity in spider silks

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P. [Department of Physical Sciences, IISER Mohali, Sector 81, Manauli, Mohali 140306 (India)

    2013-11-11

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10{sup 2−3} rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices.

  4. Optically probing torsional superelasticity in spider silks

    International Nuclear Information System (INIS)

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P.

    2013-01-01

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10 2−3 rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices

  5. Biomimetic electrospun nanofibers for tissue regeneration

    International Nuclear Information System (INIS)

    Liao, Susan; Li Bojun; Ma Zuwei; Wei He; Chan Casey; Ramakrishna, Seeram

    2006-01-01

    Nanofibers exist widely in human tissue with different patterns. Electrospinning nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibers for tissue regeneration. The advanced electrospinning technique is a promising method to fabricate a controllable continuous nanofiber scaffold similar to the natural extracellular matrix. Thus, the biomedical field has become a significant possible application field of electrospun fibers. Although electrospinning has developed rapidly over the past few years, electrospun nanofibers are still at a premature research stage. Further comprehensive and deep studies on electrospun nanofibers are essential for promoting their biomedical applications. Current electrospun fiber materials include natural polymers, synthetic polymers and inorganic substances. This review briefly describes several typically electrospun nanofiber materials or composites that have great potential for tissue regeneration, and describes their fabrication, advantages, drawbacks and future prospects. (topical review)

  6. Biofunctionalization on alkylated silicon substrate surfaces via "click" chemistry.

    Science.gov (United States)

    Qin, Guoting; Santos, Catherine; Zhang, Wen; Li, Yan; Kumar, Amit; Erasquin, Uriel J; Liu, Kai; Muradov, Pavel; Trautner, Barbara Wells; Cai, Chengzhi

    2010-11-24

    Biofunctionalization of silicon substrates is important to the development of silicon-based biosensors and devices. Compared to conventional organosiloxane films on silicon oxide intermediate layers, organic monolayers directly bound to the nonoxidized silicon substrates via Si-C bonds enhance the sensitivity of detection and the stability against hydrolytic cleavage. Such monolayers presenting a high density of terminal alkynyl groups for bioconjugation via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC, a "click" reaction) were reported. However, yields of the CuAAC reactions on these monolayer platforms were low. Also, the nonspecific adsorption of proteins on the resultant surfaces remained a major obstacle for many potential biological applications. Herein, we report a new type of "clickable" monolayers grown by selective, photoactivated surface hydrosilylation of α,ω-alkenynes, where the alkynyl terminal is protected with a trimethylgermanyl (TMG) group, on hydrogen-terminated silicon substrates. The TMG groups on the film are readily removed in aqueous solutions in the presence of Cu(I). Significantly, the degermanylation and the subsequent CuAAC reaction with various azides could be combined into a single step in good yields. Thus, oligo(ethylene glycol) (OEG) with an azido tag was attached to the TMG-alkyne surfaces, leading to OEG-terminated surfaces that reduced the nonspecific adsorption of protein (fibrinogen) by >98%. The CuAAC reaction could be performed in microarray format to generate arrays of mannose and biotin with varied densities on the protein-resistant OEG background. We also demonstrated that the monolayer platform could be functionalized with mannose for highly specific capturing of living targets (Escherichia coli expressing fimbriae) onto the silicon substrates.

  7. Differentiation of human endometrial stem cells into urothelial cells on a three-dimensional nanofibrous silk-collagen scaffold: an autologous cell resource for reconstruction of the urinary bladder wall.

    Science.gov (United States)

    Shoae-Hassani, Alireza; Mortazavi-Tabatabaei, Seyed Abdolreza; Sharif, Shiva; Seifalian, Alexander Marcus; Azimi, Alireza; Samadikuchaksaraei, Ali; Verdi, Javad

    2015-11-01

    Reconstruction of the bladder wall via in vitro differentiated stem cells on an appropriate scaffold could be used in such conditions as cancer and neurogenic urinary bladder. This study aimed to examine the potential of human endometrial stem cells (EnSCs) to form urinary bladder epithelial cells (urothelium) on nanofibrous silk-collagen scaffolds, for construction of the urinary bladder wall. After passage 4, EnSCs were induced by keratinocyte growth factor (KGF) and epidermal growth factor (EGF) and seeded on electrospun collagen-V, silk and silk-collagen nanofibres. Later we tested urothelium-specific genes and proteins (uroplakin-Ia, uroplakin-Ib, uroplakin-II, uroplakin-III and cytokeratin 20) by immunocytochemistry, RT-PCR and western blot analyses. Scanning electron microscopy (SEM) and histology were used to detect cell-matrix interactions. DMEM/F12 supplemented by KGF and EGF induced EnSCs to express urothelial cell-specific genes and proteins. Either collagen, silk or silk-collagen scaffolds promoted cell proliferation. The nanofibrous silk-collagen scaffolds provided a three-dimensional (3D) structure to maximize cell-matrix penetration and increase differentiation of the EnSCs. Human EnSCs seeded on 3D nanofibrous silk-collagen scaffolds and differentiated to urothelial cells provide a suitable source for potential use in bladder wall reconstruction in women. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Bio-functionalization of silicon nitride-based piezo-resistive ...

    Indian Academy of Sciences (India)

    Methods of bio-functionalize silicon nitride involve process steps to ... substance in applications such as clinical analysis, environmental control and industrial pro- ... anisms could be optical (measure the deflection), or measurement of a change in ... point of care (PoC), and the instrumentation involved is quite sophisticated.

  9. Vascular smooth muscle cells in cultures on biofunctionalized cellulose-based scaffolds

    Czech Academy of Sciences Publication Activity Database

    Novotná, Katarína; Bačáková, Lucie; Lisá, Věra; Havelka, P.; Sopuch, T.; Klepetář, Jan

    2009-01-01

    Roč. 12, 89-91 (2009), s. 21-24 ISSN 1429-7248 R&D Projects: GA MŠk(CZ) 2B06173; GA MPO(CZ) 2A-1TP1/073 Institutional research plan: CEZ:AV0Z50110509 Keywords : oxidized cellulose * vascular tissue engineering * biofunctionalization Subject RIV: EI - Biotechnology ; Bionics

  10. Recombinant DNA production of spider silk proteins.

    Science.gov (United States)

    Tokareva, Olena; Michalczechen-Lacerda, Valquíria A; Rech, Elíbio L; Kaplan, David L

    2013-11-01

    Spider dragline silk is considered to be the toughest biopolymer on Earth due to an extraordinary combination of strength and elasticity. Moreover, silks are biocompatible and biodegradable protein-based materials. Recent advances in genetic engineering make it possible to produce recombinant silks in heterologous hosts, opening up opportunities for large-scale production of recombinant silks for various biomedical and material science applications. We review the current strategies to produce recombinant spider silks. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  11. Structure and morphology of regenerated silk nano-fibers produced by electrospinning

    Science.gov (United States)

    Zarkoob, Shahrzad

    The impressive physical and mechanical properties of natural silk fiberssp1 and the possibility of producing these proteins using biotechnology,sp2 have provided the impetus for recent efforts in both the biosynthesissp{3,4} and the spinning of these protein based biopolymers.sp{5,6,7} The question still remains: whether fibers spun from solutions with similar chemical makeup can produce fibers with similar structures and therefore with the possibility of improved properties. Since genetically engineered silk solutions were not readily available, the first objective of this project was to completely dissolve the Bombyx mori cocoon and the Nephila clavipes dragline silk while maintaining the molecular weight integrity of the polymer. The second objective was to develop a system for re-spinning from very small amount of the resulting silk solutions by the process of electrospinning. The third objective was, to produce regenerated silk fibers with diameters that are several orders of magnitude smaller than the original fibers, suitable for direct observation and analysis by transmission electron microscopy and electron diffraction. And finally, to compare these results to structural information obtained from natural (as spun by the organism) fibers to see if the regenerated solutions are able to form the same structure as the original fibers. Both types of silk fibers were successfully dissolved while maintaining the polymer integrity. Small quantities (25-50 mul) of these solutions were used to electrospin fibers with diameters ranging from 8nm-200nm. The fibers were observed by optical, scanning electron, and transmission electron microscopy. These nano fibers showed optical retardation, appeared to have a circular cross-section, and were dimensionally stable at temperatures above 280sp°C. Electron diffraction patterns of annealed electrospun fibers of B. mori and N. clavipes showed reflections, demonstrating orientational and semicrystalline order in the material

  12. Carbon Microfibers with Hierarchical Porous Structure from Electrospun Fiber-Like Natural Biopolymer

    Science.gov (United States)

    Liang, Yeru; Wu, Dingcai; Fu, Ruowen

    2013-01-01

    Electrospinning offers a powerful route for building one-dimensional (1D) micro/nanostructures, but a common requirement for toxic or corrosive organic solvents during the preparation of precursor solution has limited their large scale synthesis and broad applications. Here we report a facile and low-cost way to prepare 1D porous carbon microfibers by using an electrospun fiber-like natural product, i.e., silk cocoon, as precursor. We surprisingly found that by utilizing a simple carbonization treatment, the cocoon microfiber can be directly transformed into 1D carbon microfiber of ca. 6 μm diameter with a unique three-dimensional porous network structure composed of interconnected carbon nanoparticles of 10~40 nm diameter. We further showed that the as-prepared carbon product presents superior electrochemical performance as binder-free electrodes of supercapacitors and good adsorption property toward organic vapor.

  13. PEGylated Silk Nanoparticles for Anticancer Drug Delivery.

    Science.gov (United States)

    Wongpinyochit, Thidarat; Uhlmann, Petra; Urquhart, Andrew J; Seib, F Philipp

    2015-11-09

    Silk has a robust clinical track record and is emerging as a promising biopolymer for drug delivery, including its use as nanomedicine. However, silk-based nanomedicines still require further refinements for full exploitation of their potential; the application of "stealth" design principals is especially necessary to support their evolution. The aim of this study was to develop and examine the potential of PEGylated silk nanoparticles as an anticancer drug delivery system. We first generated B. mori derived silk nanoparticles by driving β-sheet assembly (size 104 ± 1.7 nm, zeta potential -56 ± 5.6 mV) using nanoprecipitation. We then surface grafted polyethylene glycol (PEG) to the fabricated silk nanoparticles and verified the aqueous stability and morphology of the resulting PEGylated silk nanoparticles. We assessed the drug loading and release behavior of these nanoparticles using clinically established and emerging anticancer drugs. Overall, PEGylated silk nanoparticles showed high encapsulation efficiency (>93%) and a pH-dependent release over 14 days. Finally, we demonstrated significant cytotoxicity of drug loaded silk nanoparticles applied as single and combination nanomedicines to human breast cancer cells. In conclusion, these results, taken together with prior silk nanoparticle data, support a viable future for silk-based nanomedicines.

  14. Effect of. gamma. -irradiation on the crystalline structure of silk fibroin and silk sericin

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Masuhiro; Aoki, Akira

    1985-02-01

    Changes in the crystalline structure of silk sericin and silk fibroin induced by gamma-irradiation in the atmosphere described. The crystalline structure of silk sericin which had been subjected to gamma-irradiation remained unchanged. However the decomposition temperature of the specimen decreased to about 230 deg C, when the total dose of ..gamma.. rays exceeded 4.6 Mrad. The structure of the silk 1 type crystal of silk fibroin in the solid state, with a low degree of molecular orientation, changed into the silk 2 type crystal, when the total dose of ..gamma.. rays exceeded 4.6 Mrad. No changes in the crystalline structure were observed in the solid state of the silk 2 type crystal regardless of gamma-irradiation. The decrease in the decomposition temperature of the specimen was attributed to the decrease in the molecular orientation. However, the molecular conformation of silk fibroin with a randomly coiled structure remained unchanged even after gamma-irradiation.

  15. Politics of contemporary "Silk Roads"

    Directory of Open Access Journals (Sweden)

    Andrey I. Litvinov

    2016-01-01

    Full Text Available Recently in mass media we can find the idea about a new Silk Road or the concept of "Silk Road Economic Belt" which has been formulated by the Chinese PresidentXi Jinping on September 7,2013, during his official visit to Kazakhstan. This project is not only the creation of a transport, power and trade corridor, and also the project which will promote development of tourism in the region and to strengthening of cultural exchanges of China with the countries of Central Asia, it also includes construction of a network of high-speed fiber-optical networks. The economic strip of the Silk Road will begin in China and pass across the Central and the Southern Asia, part of branches across the territory of the Russian Federation and to leave to Europe. This international investment project assumes creation of a continental transport way. For implementation of overland part of "A great Silk Road is a three railway corridors (northern, central have to be constructed and southern They have form a basis for development of other means of transport, including automobile subsequently. Construction of these three railway corridors acts as the most important and necessary stage of implementation of the project. The government of China declares that creation of an economic belt of the Silk way is a revival of once prospering trade-transport and cultural corridor from Asia to Europe which will promote activization of a friendly exchange between the people of the different countries. Further all this has to connect trade and economic space of Europe and Asia in a whole that has to serve implementation of deeper economic cooperation, between the countries participating in him, to increase in a trade turnover and expansion of scientific and technical exchanges between them.

  16. BioMimic fabrication of electrospun nanofibers with high-throughput

    International Nuclear Information System (INIS)

    He Jihuan; Liu Yong; Xu Lan; Yu Jianyong; Sun Gang

    2008-01-01

    Spider-spun fiber is of extraordinary strength and toughness comparable to those of electrospun fiber, the later needs a very high voltage (from several thousands voltage to several ten thousands voltages) applied to water-soluble protein 'soup' that was produced by a spider, furthermore, its mechanical strength dramatically decreases comparable to spider silk. A possible mechanism in spider-spinning process is given, the distinct character in spider-spinning is that its spinneret consists of millions of nano scale tubes, and a bubble can be produced at the apex of each nano-tube. The surface tension of each bubble is extremely small such that it can be spun into nanofibers with an awfully small force, either by the spider's body weight or tension created by the rear legs. We mimic the spider-spinning in electrospinning using an aerated solution, which leads to various small bubbles on surface with very small surface tension, as a result the bubble can be easily electrospun into nanofibers with low applied voltage. This fabrication process possesses features of high productivity, versatility, in addition, the minimum diameter of nanofibers produced by this process can reach as small as 50 nm

  17. PEGylated Silk Nanoparticles for Anticancer Drug Delivery

    DEFF Research Database (Denmark)

    Wongpinyochit, Thidarat; Uhlmann, Petra; Urquhart, Andrew

    2015-01-01

    Silk has a robust clinical track record and is emerging as a promising biopolymer for drug delivery, including its use as nanomedicine. However, silk-based nanomedicines still require further refinements for full exploitation of their potential; the application of “stealth” design principals...... is especially necessary to support their evolution. The aim of this study was to develop and examine the potential of PEGylated silk nanoparticles as an anticancer drug delivery system. We first generated B. mori derived silk nanoparticles by driving β-sheet assembly (size 104 ± 1.7 nm, zeta potential −56 ± 5.......6 mV) using nanoprecipitation. We then surface grafted polyethylene glycol (PEG) to the fabricated silk nanoparticles and verified the aqueous stability and morphology of the resulting PEGylated silk nanoparticles. We assessed the drug loading and release behavior of these nanoparticles using...

  18. Silk nanoparticles—an emerging anticancer nanomedicine

    Directory of Open Access Journals (Sweden)

    F. Philipp Seib

    2017-03-01

    Full Text Available Silk is a sustainable and ecologically friendly biopolymer with a robust clinical track record in humans for load bearing applications, in part due to its excellent mechanical properties and biocompatibility. Our ability to take bottom-up and top-down approaches for the generation of silk (inspired biopolymers has been critical in supporting the evolution of silk materials and formats, including silk nanoparticles for drug delivery. Silk nanoparticles are emerging as interesting contenders for drug delivery and are well placed to advance the nanomedicine field. This review covers the use of Bombyx mori and recombinant silks as an anticancer nanomedicine, highlighting the emerging trends and developments as well as critically assessing the current opportunities and challenges by providing a context specific assessment of this multidisciplinary field.

  19. Thromboelastometric and platelet responses to silk biomaterials.

    Science.gov (United States)

    Kundu, Banani; Schlimp, Christoph J; Nürnberger, Sylvia; Redl, Heinz; Kundu, S C

    2014-05-13

    Silkworm's silk is natural biopolymer with unique properties including mechanical robustness, all aqueous base processing and ease in fabrication into different multifunctional templates. Additionally, the nonmulberry silks have cell adhesion promoting tri-peptide (RGD) sequences, which make it an immensely potential platform for regenerative medicine. The compatibility of nonmulberry silk with human blood is still elusive; thereby, restricts its further application as implants. The present study, therefore, evaluate the haematocompatibility of silk biomaterials in terms of platelet interaction after exposure to nonmulberry silk of Antheraea mylitta using thromboelastometry (ROTEM). The mulberry silk of Bombyx mori and clinically used Uni-Graft W biomaterial serve as references. Shortened clotting time, clot formation times as well as enhanced clot strength indicate the platelet mediated activation of blood coagulation cascade by tested biomaterials; which is comparable to controls.

  20. Biofunctionalization on Alkylated Silicon Substrate Surfaces via “Click” Chemistry

    OpenAIRE

    Qin, Guoting; Santos, Catherine; Zhang, Wen; Li, Yan; Kumar, Amit; Erasquin, Uriel J.; Liu, Kai; Muradov, Pavel; Trautner, Barbara Wells; Cai, Chengzhi

    2010-01-01

    Biofunctionalization of silicon substrates is important to the development of silicon-based biosensors and devices. Compared to conventional organosiloxane films on silicon oxide intermediate layers, organic monolayers directly bound to the non-oxidized silicon substrates via Si-C bonds enhance the sensitivity of detection and the stability against hydrolytic cleavage. Such monolayers presenting a high density of terminal alkynyl groups for bioconjugation via copper-catalyzed azide-alkyne 1,3...

  1. D-Amino acid oxidase bio-functionalized platforms: Toward an enhanced enzymatic bio-activity

    Science.gov (United States)

    Herrera, Elisa; Valdez Taubas, Javier; Giacomelli, Carla E.

    2015-11-01

    The purpose of this work is to study the adsorption process and surface bio-activity of His-tagged D-amino acid oxidase (DAAO) from Rhodotorula gracilis (His6-RgDAAO) as the first step for the development of an electrochemical bio-functionalized platform. With such a purpose this work comprises: (a) the His6-RgDAAO bio-activity in solution determined by amperometry, (b) the adsorption mechanism of His6-RgDAAO on bare gold and carboxylated modified substrates in the absence (substrate/COO-) and presence of Ni(II) (substrate/COO- + Ni(II)) determined by reflectometry, and (c) the bio-activity of the His6-RgDAAO bio-functionalized platforms determined by amperometry. Comparing the adsorption behavior and bio-activity of His6-RgDAAO on these different solid substrates allows understanding the contribution of the diverse interactions responsible for the platform performance. His6-RgDAAO enzymatic performance in solution is highly improved when compared to the previously used pig kidney (pk) DAAO. His6-RgDAAO exhibits an amperometrically detectable bio-activity at concentrations as low as those expected on a bio-functional platform; hence, it is a viable bio-recognition element of D-amino acids to be coupled to electrochemical platforms. Moreover, His6-RgDAAO bio-functionalized platforms exhibit a higher surface activity than pkDAAO physically adsorbed on gold. The platform built on Ni(II) modified substrates present enhanced bio-activity because the surface complexes histidine-Ni(II) provide with site-oriented, native-like enzymes. The adsorption mechanism responsible of the excellent performance of the bio-functionalized platform takes place in two steps involving electrostatic and bio-affinity interactions whose prevalence depends on the degree of surface coverage.

  2. Facile biofunctionalization of silver nanoparticles for enhanced antibacterial properties, endotoxin removal, and biofilm control

    Directory of Open Access Journals (Sweden)

    Lambadi PR

    2015-03-01

    Full Text Available Paramesh Ramulu Lambadi,1,* Tarun Kumar Sharma,1,* Piyush Kumar,1 Priyanka Vasnani,2 Sitaramanjaneya Mouli Thalluri,2 Neha Bisht,1 Ranjana Pathania,1,2 Naveen Kumar Navani1,21Department of Biotechnology, 2Centre of Nanotechnology, Indian Institute of Technology, Roorkee, Uttarakhand, India*These authors contributed equally to this workAbstract: Infectious diseases cause a huge burden on healthcare systems worldwide. Pathogenic bacteria establish infection by developing antibiotic resistance and modulating the host’s immune system, whereas opportunistic pathogens like Pseudomonas aeruginosa adapt to adverse conditions owing to their ability to form biofilms. In the present study, silver nanoparticles were biofunctionalized with polymyxin B, an antibacterial peptide using a facile method. The biofunctionalized nanoparticles (polymyxin B-capped silver nanoparticles, PBSNPs were assessed for antibacterial activity against multiple drug-resistant clinical strain Vibrio fluvialis and nosocomial pathogen P. aeruginosa. The results of antibacterial assay revealed that PBSNPs had an approximately 3-fold higher effect than the citrate-capped nanoparticles (CSNPs. Morphological damage to the cell membrane was followed by scanning electron microscopy, testifying PBSNPs to be more potent in controlling the bacterial growth as compared with CSNPs. The bactericidal effect of PBSNPs was further confirmed by Live/Dead staining assays. Apart from the antibacterial activity, the biofunctionalized nanoparticles were found to resist biofilm formation. Electroplating of PBSNPs onto stainless steel surgical blades retained the antibacterial activity against P. aeruginosa. Further, the affinity of polymyxin for endotoxin was exploited for its removal using PBSNPs. It was found that the prepared nanoparticles removed 97% of the endotoxin from the solution. Such multifarious uses of metal nanoparticles are an attractive means of enhancing the potency of antimicrobial

  3. Nanomechanics of electrospun phospholipid fiber

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Ana C., E-mail: anac@food.dtu.dk, E-mail: ioach@food.dtu.dk; Chronakis, Ioannis S., E-mail: anac@food.dtu.dk, E-mail: ioach@food.dtu.dk [Technical University of Denmark, DTU-Food, Søltofts Plads B227, DK-2800, Kgs. Lyngby (Denmark); Nikogeorgos, Nikolaos; Lee, Seunghwan [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2015-06-01

    Electrospun asolectin phospholipid fibers were prepared using isooctane as a solvent and had an average diameter of 6.1 ± 2.7 μm. Their mechanical properties were evaluated by nanoindentation using Atomic Force Microscopy, and their elastic modulus was found to be approximately 17.2 ± 1 MPa. At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip. The phospholipid fibers were shown to be stable in ambient conditions, preserving the modulus of elasticity up to 24 h.

  4. Nanomechanics of electrospun phospholipid fiber

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Nikogeorgos, Nikolaos; Lee, Seunghwan

    2015-01-01

    Electrospun asolectin phospholipid fibers were prepared using isooctane as a solvent and had an average diameter of 6.1 +/- 2.7 mu m. Their mechanical properties were evaluated by nanoindentation using Atomic Force Microscopy, and their elastic modulus was found to be approximately 17.2 +/- 1MPa....... At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip....... The phospholipid fibers were shown to be stable in ambient conditions, preserving the modulus of elasticity up to 24 h. (c) 2015 AIP Publishing LLC....

  5. The Use of Silk in Nanomedicine Applications

    DEFF Research Database (Denmark)

    Chiasson, Raymond; Hasan, Moaraj; Al Nazer, Q.

    2016-01-01

    Biopolymers made up of silk proteins have been used in numerous drug delivery applications and represent an excellent source of natural biomaterials. In particular silk fibroin has proved valuable as a building block for nanomedicines and drug delivery implants, owing to its favorable...... biocompatibility, degradation, stabilization and controllability. In this chapter we will discuss the various sources of silk biomaterial and how this naturally occurring biopolymer has been utilized in the development of nanomedicines and implantable drug delivery systems, demonstrating how silk is a unique...

  6. The Silk Route from Land to Sea

    Directory of Open Access Journals (Sweden)

    Jack Weatherford

    2018-04-01

    Full Text Available The Silk Route reached its historic and economic apogee under the Mongol Empire (1207–1368, as a direct result of the policies of Chinggis Khan (Genghis Khan and his successors. Because the land network proved inefficient for the amount of goods needing transport from one part of the empire to another, the Mongols expanded the Silk Route to ocean shipping and thus created the first Maritime Silk Route. The sea traffic initially expanded the land routes but soon strangled them. With the expansion of the Maritime Silk Route through the fourteenth century, the land connections reverted to local networks and lost their global importance.

  7. Selective individual primary cell capture using locally bio-functionalized micropores.

    Directory of Open Access Journals (Sweden)

    Jie Liu

    Full Text Available BACKGROUND: Solid-state micropores have been widely employed for 6 decades to recognize and size flowing unlabeled cells. However, the resistive-pulse technique presents limitations when the cells to be differentiated have overlapping dimension ranges such as B and T lymphocytes. An alternative approach would be to specifically capture cells by solid-state micropores. Here, the inner wall of 15-µm pores made in 10 µm-thick silicon membranes was covered with antibodies specific to cell surface proteins of B or T lymphocytes. The selective trapping of individual unlabeled cells in a bio-functionalized micropore makes them recognizable just using optical microscopy. METHODOLOGY/PRINCIPAL FINDINGS: We locally deposited oligodeoxynucleotide (ODN and ODN-conjugated antibody probes on the inner wall of the micropores by forming thin films of polypyrrole-ODN copolymers using contactless electro-functionalization. The trapping capabilities of the bio-functionalized micropores were validated using optical microscopy and the resistive-pulse technique by selectively capturing polystyrene microbeads coated with complementary ODN. B or T lymphocytes from a mouse splenocyte suspension were specifically immobilized on micropore walls functionalized with complementary ODN-conjugated antibodies targeting cell surface proteins. CONCLUSIONS/SIGNIFICANCE: The results showed that locally bio-functionalized micropores can isolate target cells from a suspension during their translocation throughout the pore, including among cells of similar dimensions in complex mixtures.

  8. Selective Individual Primary Cell Capture Using Locally Bio-Functionalized Micropores

    Science.gov (United States)

    Liu, Jie; Bombera, Radoslaw; Leroy, Loïc; Roupioz, Yoann; Baganizi, Dieudonné R.; Marche, Patrice N.; Haguet, Vincent; Mailley, Pascal; Livache, Thierry

    2013-01-01

    Background Solid-state micropores have been widely employed for 6 decades to recognize and size flowing unlabeled cells. However, the resistive-pulse technique presents limitations when the cells to be differentiated have overlapping dimension ranges such as B and T lymphocytes. An alternative approach would be to specifically capture cells by solid-state micropores. Here, the inner wall of 15-µm pores made in 10 µm-thick silicon membranes was covered with antibodies specific to cell surface proteins of B or T lymphocytes. The selective trapping of individual unlabeled cells in a bio-functionalized micropore makes them recognizable just using optical microscopy. Methodology/Principal Findings We locally deposited oligodeoxynucleotide (ODN) and ODN-conjugated antibody probes on the inner wall of the micropores by forming thin films of polypyrrole-ODN copolymers using contactless electro-functionalization. The trapping capabilities of the bio-functionalized micropores were validated using optical microscopy and the resistive-pulse technique by selectively capturing polystyrene microbeads coated with complementary ODN. B or T lymphocytes from a mouse splenocyte suspension were specifically immobilized on micropore walls functionalized with complementary ODN-conjugated antibodies targeting cell surface proteins. Conclusions/Significance The results showed that locally bio-functionalized micropores can isolate target cells from a suspension during their translocation throughout the pore, including among cells of similar dimensions in complex mixtures. PMID:23469221

  9. Trends in World Silk Cocoons and Silk Production and Trade, 2007-2010

    Directory of Open Access Journals (Sweden)

    AGATHA AGATHA POPESCU

    2013-10-01

    Full Text Available The paper aimed to analyze world production and trade for fresh silk cocoons and raw silk using FAO Stat data for  the  period 2007-2010. The use of index, share and comparison methods allowed to identify the major trends in the analyzed period. Silk decline was determined by the increased importance of cotton and artificial fibres in textile and clothing industry. Important changes are taking place on silk cocoons and silk market. While, the European market decreased, the Asian market has mainly developed fresh cocoons and raw silk, while the European market became more interested of clothes. Silk consumption declined because of consumer’s preference for synthetic fibres, except traditional consumers from Asia.  China is the main producer and exporter of fresh and dry cocoons, while raw silk is produced and exported by China, Brazil and Italy and imported by India, Japan and Italy. In Europe, Bulgaria is the top producer of fresh cocoons and raw silk and Italy is the main raw silk importer and the top producer and exporter of textile and fashion clothes. Silk will remain an important raw material for producing high quality and luxury clothes.

  10. Silk film biomaterials for ocular surface repair

    Science.gov (United States)

    Lawrence, Brian David

    Current biomaterial approaches for repairing the cornea's ocular surface upon injury are partially effective due to inherent material limitations. As a result there is a need to expand the biomaterial options available for use in the eye, which in turn will help to expand new clinical innovations and technology development. The studies illustrated here are a collection of work to further characterize silk film biomaterials for use on the ocular surface. Silk films were produced from regenerated fibroin protein solution derived from the Bombyx mori silkworm cocoon. Methods of silk film processing and production were developed to produce consistent biomaterials for in vitro and in vivo evaluation. A wide range of experiments was undertaken that spanned from in vitro silk film material characterization to in vivo evaluation. It was found that a variety of silk film properties could be controlled through a water-annealing process. Silk films were then generated that could be use in vitro to produce stratified corneal epithelial cell sheets comparable to tissue grown on the clinical standard substrate of amniotic membrane. This understanding was translated to produce a silk film design that enhanced corneal healing in vivo on a rabbit injury model. Further work produced silk films with varying surface topographies that were used as a simplified analog to the corneal basement membrane surface in vitro. These studies demonstrated that silk film surface topography is capable of directing corneal epithelial cell attachment, growth, and migration response. Most notably epithelial tissue development was controllably directed by the presence of the silk surface topography through increasing cell sheet migration efficiency at the individual cellular level. Taken together, the presented findings represent a comprehensive characterization of silk film biomaterials for use in ocular surface reconstruction, and indicate their utility as a potential material choice in the

  11. Punctuated evolution of viscid silk in spider orb webs supported by mechanical behavior of wet cribellate silk

    Science.gov (United States)

    Piorkowski, Dakota; Blackledge, Todd A.

    2017-08-01

    The origin of viscid capture silk in orb webs, from cribellate silk-spinning ancestors, is a key innovation correlated with significant diversification of web-building spiders. Ancestral cribellate silk consists of dry nanofibrils surrounding a stiff, axial fiber that adheres to prey through van der Waals interactions, capillary forces, and physical entanglement. In contrast, viscid silk uses chemically adhesive aqueous glue coated onto a highly compliant and extensible flagelliform core silk. The extensibility of the flagelliform fiber accounts for half of the total work of adhesion for viscid silk and is enabled by water in the aqueous coating. Recent cDNA libraries revealed the expression of flagelliform silk proteins in cribellate orb-weaving spiders. We hypothesized that the presence of flagelliform proteins in cribellate silk could have allowed for a gradual shift in mechanical performance of cribellate axial silk, whose effect was masked by the dry nature of its adhesive. We measured supercontraction and mechanical performance of cribellate axial silk, in wet and dry states, for two species of cribellate orb web-weaving spiders to see if water enabled flagelliform silk-like performance. We found that compliance and extensibility of wet cribellate silk increased compared to dry state as expected. However, when compared to other silk types, the response to water was more similar to other web silks, like major and minor ampullate silk, than to viscid silk. These findings support the punctuated evolution of viscid silk mechanical performance.

  12. Fabrication of elastomeric silk fibers.

    Science.gov (United States)

    Bradner, Sarah A; Partlow, Benjamin P; Cebe, Peggy; Omenetto, Fiorenzo G; Kaplan, David L

    2017-09-01

    Methods to generate fibers from hydrogels, with control over mechanical properties, fiber diameter, and crystallinity, while retaining cytocompatibility and degradability, would expand options for biomaterials. Here, we exploited features of silk fibroin protein for the formation of tunable silk hydrogel fibers. The biological, chemical, and morphological features inherent to silk were combined with elastomeric properties gained through enzymatic crosslinking of the protein. Postprocessing via methanol and autoclaving provided tunable control of fiber features. Mechanical, optical, and chemical analyses demonstrated control of fiber properties by exploiting the physical cross-links, and generating double network hydrogels consisting of chemical and physical cross-links. Structure and chemical analyses revealed crystallinity from 30 to 50%, modulus from 0.5 to 4 MPa, and ultimate strength 1-5 MPa depending on the processing method. Fabrication and postprocessing combined provided fibers with extensibility from 100 to 400% ultimate strain. Fibers strained to 100% exhibited fourth order birefringence, revealing macroscopic orientation driven by chain mobility. The physical cross-links were influenced in part by the drying rate of fabricated materials, where bound water, packing density, and microstructural homogeneity influenced cross-linking efficiency. The ability to generate robust and versatile hydrogel microfibers is desirable for bottom-up assembly of biological tissues and for broader biomaterial applications. © 2017 Wiley Periodicals, Inc.

  13. SILK FIBRE DEGRADATION AND ANALYSIS BY PROTEOMICS

    Directory of Open Access Journals (Sweden)

    YUKSELOGLU S.Muge

    2016-05-01

    Full Text Available Silk is one of the promising natural fibres and has a long established history in textile production throughout the centuries. Silk is produced by cultured silk worms, spiders, scorpions, mites and flies. It is extracellular proteinaceous fibres which consist of highly crystalline and insoluble proteins, the fibroins glued with sericin and an amourphous protein. On the other hand, understanding and controlling the degradation of protein materials are important for determining quality and the value of appearance retention in textiles. Hence, for silk textiles, appearance retention is critical value for the quality. And this is one of the key properties directly related to the degree and nature of protein degradation. It is therefore necessary to understand the silk composition and damage to obtain good conservation treatments and long-term preservation especially for the historical silk fabrics. In this study, silk fibre and its properties are briefly introduced along with images on their fibre damages. Additionally, proteomics method which helps to understand the degradation at the molecular level in textiles is introduced. Finally, proteomic evaluation of silk is summarized according to the researchers carried out in the literature.

  14. Silkworms transformed with chimeric silkworm/spider silk genes spin composite silk fibers with improved mechanical properties

    Science.gov (United States)

    The development of a spider silk manufacturing process is of great interest. piggyBac vectors were used to create transgenic silkworms encoding chimeric silkworm/spider silk proteins. The silk fibers produced by these animals were composite materials that included chimeric silkworm/spider silk prote...

  15. Nanofibrous silk fibroin/reduced graphene oxide scaffolds for tissue engineering and cell culture applications.

    Science.gov (United States)

    Nalvuran, Hande; Elçin, Ayşe Eser; Elçin, Yaşar Murat

    2018-03-16

    Graphene and silk fibroin (SF) have been extensively investigated in the literature. Hybrid scaffolds of SF and graphene combine the properties of both of the materials and provide promising applications for tissue engineering purposes. In this study, reduced graphene oxide (RGO) (0.5%, 1.0% and 2.0% (w/v)) was incorporated into SF and fabricated into composite nanofibers through electrospinning. The fibers were characterized and analyzed by SEM, XRD, FTIR, TGA, circular dichroism analysis, contact angle measurements and tensile tests. Here, we document that the presence of RGO increases intermolecular forces between RGO and SF molecular chains in the SF matrix, which results in an increased silk II content. Upon the incorporation of RGO, thermal stability and mechanical properties of the fibers significantly improved. Furthermore, in-vitro findings showed that composite nanofibers supported cell viability and were hemocompatible. Finally, bone marrow mesenchymal stem cells were induced osteogenically on electrospun SF/RGO mats for 30days, which showed that the substrate supported osteogenic differentiation. In this study, a feasible method is proposed to generate biocompatible and versatile SF/RGO-composite nanofibers that can influence biomedical applications. Copyright © 2018. Published by Elsevier B.V.

  16. The Electrospun Ceramic Hollow Nanofibers

    Directory of Open Access Journals (Sweden)

    Shahin Homaeigohar

    2017-11-01

    Full Text Available Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, and their sensitivity. In particular, semiconductor ceramic hollow nanofibers show greater space charge modulation depth, higher electronic transport properties, and shorter ion or electron diffusion length (e.g., for an enhanced charging–discharging rate. In this review, we discuss and introduce the latest developments of ceramic hollow nanofiber materials in terms of synthesis approaches. Particularly, electrospinning derivatives will be highlighted. The electrospun ceramic hollow nanofibers will be reviewed with respect to their most widely studied components, i.e., metal oxides. These nanostructures have been mainly suggested for energy and environmental remediation. Despite the various advantages of such one dimensional (1D nanostructures, their fabrication strategies need to be improved to increase their practical use. The domain of nanofabrication is still advancing, and its predictable shortcomings and bottlenecks must be identified and addressed. Inconsistency of the hollow nanostructure with regard to their composition and dimensions could be one of such challenges. Moreover, their poor scalability hinders their wide applicability for commercialization and industrial use.

  17. Buyid Silk and the Tale of Bibi Shahrbanu: Identification of Biomarkers of Artificial Aging (Forgery) of Silk.

    Science.gov (United States)

    Moini, Mehdi; Rollman, Christopher M

    2017-10-03

    Buyid silk forgery is one of the most famous silk forgeries in the world. In 1924-1925, excavation of the Bibi Shahrbanu site in Iran unearthed several silk textiles. The silks were thought to be of the Buyid period (934-1062 BCE) of the Persian Empire and have since been known as the "Buyid silks". In the 1930s, more silk appeared and was reported as being from the Buyid period as well. Controversy over the authenticity of these silks escalated after the purchase of the silks by museums throughout the world. Extensive investigations of several of these silks have been conducted over the years with respect to iconography, weaving patterns, dyes/mordant, style, and even radiocarbon dating. It was found that most of the silks are not from Buyid period. To test the authenticity of these silk fabrics, the recently developed silk dating technique using amino acid racemization (AAR) in conjunction with capillary electrophoresis mass spectrometry was applied to 13 Buyid silk specimens from the Textile Museum collections. Among these silk specimens, the AAR ratios of only one specimen were consistent with authentic silk fabrics collected from various museums. In addition, the aspartic acid racemization ratio of this specimen was also consistent with its 14 C dating. The other "Buyid silks" showed excessive levels of amino acid racemization not only for aspartic acid, but also for phenylalanine and tyrosine, inconsistent with racemization rates of these amino acids in authentic historical silk fabrics. Treatment of modern silk with a base at different pH and temperature reproduced the AAR pattern of the Buyid silks, implying that chemical treatment with a base at relatively high temperatures was perhaps the method used to artificially age these fabrics. The results imply that the racemization ratios of aspartic acid, phenylalanine, and tyrosine can be used as biomarkers for identification of naturally versus artificially aged silk.

  18. Production of silk sericin/silk fibroin blend nanofibers

    Directory of Open Access Journals (Sweden)

    Zhang Xianhua

    2011-01-01

    Full Text Available Abstract Silk sericin (SS/silk fibroin (SF blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters of the SS/SF (75/25, 50/50, and 25/75 blend nanofibers were much thicker than that of SS and SF nanofibers. The SS/SF (100/0, 75/25, and 50/50 blend nanofibers were easily dissolved in water, while the SS/SF (25/75 and 0/100 blend nanofibers could not be completely dissolved in water. The SS/SF blend nanofibers could not be completely dissolved in methanol. The SS/SF blend nanofibers were characterized by Fourier transform infrared (FTIR spectroscopy, differential scanning calorimetry, and differential thermal analysis. FTIR showed that the SS/SF blend nanofibers possessed a random coil conformation and ß-sheet structure.

  19. Effects of bio-functionalizing surface treatments on the mechanical behavior of open porous titanium biomaterials.

    Science.gov (United States)

    Amin Yavari, S; Ahmadi, S M; van der Stok, J; Wauthle, R; Riemslag, A C; Janssen, M; Schrooten, J; Weinans, H; Zadpoor, A A

    2014-08-01

    Bio-functionalizing surface treatments are often applied for improving the bioactivity of biomaterials that are based on otherwise bioinert titanium alloys. When applied on highly porous titanium alloy structures intended for orthopedic bone regeneration purposes, such surface treatments could significantly change the static and fatigue properties of these structures and, thus, affect the application of the biomaterial as bone substitute. Therefore, the interplay between biofunctionalizing surface treatments and mechanical behavior needs to be controlled. In this paper, we studied the effects of two bio-functionalizing surface treatments, namely alkali-acid heat treatment (AlAcH) and acid-alkali (AcAl), on the static and fatigue properties of three different highly porous titanium alloy implants manufactured using selective laser melting. It was found that AlAcH treatment results in minimal mass loss. The static and fatigue properties of AlAcH specimens were therefore not much different from as-manufactured (AsM) specimens. In contrast, AcAl resulted in substantial mass loss and also in significantly less static and fatigue properties particularly for porous structures with the highest porosity. The ratio of the static mechanical properties of AcAl specimens to that of AsM specimen was in the range of 1.5-6. The fatigue lives of AcAl specimens were much more severely affected by the applied surface treatments with fatigue lives up to 23 times smaller than that of AsM specimens particularly for the porous structures with the highest porosity. In conclusion, the fatigue properties of surface treated porous titanium are dependent not only on the type of applied surface treatment but also on the porosity of the biomaterial. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Silk Electrogel Based Gastroretentive Drug Delivery System

    Science.gov (United States)

    Wang, Qianrui

    Gastric cancer has become a global pandemic and there is imperative to develop efficient therapies. Oral dosing strategy is the preferred route to deliver drugs for treating the disease. Recent studies suggested silk electro hydrogel, which is pH sensitive and reversible, has potential as a vehicle to deliver the drug in the stomach environment. The aim of this study is to establish in vitro electrogelation e-gel based silk gel as a gastroretentive drug delivery system. We successfully extended the duration of silk e-gel in artificial gastric juice by mixing silk solution with glycerol at different ratios before the electrogelation. Structural analysis indicated the extended duration was due to the change of beta sheet content. The glycerol mixed silk e-gel had good doxorubicin loading capability and could release doxorubicin in a sustained-release profile. Doxorubicin loaded silk e-gels were applied to human gastric cancer cells. Significant cell viability decrease was observed. We believe that with further characterization as well as functional analysis, the silk e-gel system has the potential to become an effective vehicle for gastric drug delivery applications.

  1. Silk Spinning in Silkworms and Spiders.

    Science.gov (United States)

    Andersson, Marlene; Johansson, Jan; Rising, Anna

    2016-08-09

    Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and spiders, with the aim of identifying features that are important for fiber formation. Although spiders and silkworms are very distantly related, some features of spinning silk seem to be universal. Both spiders and silkworms produce large silk proteins that are highly repetitive and extremely soluble at high pH, likely due to the globular terminal domains that flank an intermediate repetitive region. The silk proteins are produced and stored at a very high concentration in glands, and then transported along a narrowing tube in which they change conformation in response primarily to a pH gradient generated by carbonic anhydrase and proton pumps, as well as to ions and shear forces. The silk proteins thereby convert from random coil and alpha helical soluble conformations to beta sheet fibers. We suggest that factors that need to be optimized for successful production of artificial silk proteins capable of forming tough fibers include protein solubility, pH sensitivity, and preservation of natively folded proteins throughout the purification and initial spinning processes.

  2. Electrospun nanofibers for energy and environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Bin; Yu, Jianyong (eds.) [Donghua Univ., Shanghai (China). State Key Lab. for Modification of Chemical Fibers and Polymer Materials; Donghua Univ., Shanghai (China). Nanomaterials Research Center

    2014-10-01

    This book offers a comprehensive review of the latest advances in developing functional electrospun nanofibers for energy and environmental applications, which include fuel cells, lithium-ion batteries, solar cells, supercapacitors, energy storage materials, sensors, filtration materials, protective clothing, catalysis, structurally-colored fibers, oil spill cleanup, self-cleaning materials, adsorbents, and electromagnetic shielding.

  3. Electrospun Superhydrophobic Self-Cleaning Materials

    Science.gov (United States)

    Zhao, Yong; Wang, Nü

    In this chapter, we introduce the wettability of electrospinning products. Especially, we concentrate on the fabrication, characteristics, and applications of the electrospun self-cleaning materials. Self-cleaning materials are typical nature-inspired artificial materials learning from such as lotus leaf and many other plants or animals. Self-cleaning materials usually rely on a superhydrophobic surface, which should be of low surface free energy as well as large surface roughness. Electrospinning method is such a method that could facilely shape various hydrophobic polymers into ultrathin fibers with tunable surface microstructures. It means the electrospun products are of very large specific area, which satisfy the two basic conditions in preparing superhydrophobic surfaces. Therefore, in the last decade, scientists put forward a good few of elegant approaches to fabricate superhydrophobic materials by electrospinning. These methods can be generally classified into two routes. One is a direct route that creates superhydrophobic electrospun films from hydrophobic materials. Another is an indirect route that decorates electrospun nanofibers (no matter hydrophobic or hydrophilic) with hydrophobic chemicals. We first introduce some representative works on the fabrication of superhydrophobic self-cleaning materials by electrospinning method. Then we show some applications of these superhydrophobic materials. Finally, we give a brief personal perspective on this area.

  4. Spider Silk Fibers Spun from Soluble Recombinant Silk Produced in Mammalian Cells

    Science.gov (United States)

    Lazaris, Anthoula; Arcidiacono, Steven; Huang, Yue; Zhou, Jiang-Feng; Duguay, François; Chretien, Nathalie; Welsh, Elizabeth A.; Soares, Jason W.; Karatzas, Costas N.

    2002-01-01

    Spider silks are protein-based ``biopolymer'' filaments or threads secreted by specialized epithelial cells as concentrated soluble precursors of highly repetitive primary sequences. Spider dragline silk is a flexible, lightweight fiber of extraordinary strength and toughness comparable to that of synthetic high-performance fibers. We sought to ``biomimic'' the process of spider silk production by expressing in mammalian cells the dragline silk genes (ADF-3/MaSpII and MaSpI) of two spider species. We produced soluble recombinant (rc)-dragline silk proteins with molecular masses of 60 to 140 kilodaltons. We demonstrated the wet spinning of silk monofilaments spun from a concentrated aqueous solution of soluble rc-spider silk protein (ADF-3; 60 kilodaltons) under modest shear and coagulation conditions. The spun fibers were water insoluble with a fine diameter (10 to 40 micrometers) and exhibited toughness and modulus values comparable to those of native dragline silks but with lower tenacity. Dope solutions with rc-silk protein concentrations >20% and postspinning draw were necessary to achieve improved mechanical properties of the spun fibers. Fiber properties correlated with finer fiber diameter and increased birefringence.

  5. Uncovering the structure-function relationship in spider silk

    Science.gov (United States)

    Yarger, Jeffery L.; Cherry, Brian R.; van der Vaart, Arjan

    2018-03-01

    All spiders produce protein-based biopolymer fibres that we call silk. The most studied of these silks is spider dragline silk, which is very tough and relatively abundant compared with other types of spider silks. Considerable research has been devoted to understanding the relationship between the molecular structure and mechanical properties of spider dragline silks. In this Review, we overview experimental and computational studies that have provided a wealth of detail at the molecular level on the highly conserved repetitive core and terminal regions of spider dragline silk. We also discuss the role of the nanocrystalline β-sheets and amorphous regions in determining the properties of spider silk fibres, endowing them with strength and elasticity. Additionally, we outline imaging techniques and modelling studies that elucidate the importance of the hierarchical structure of silk fibres at the molecular level. These insights into structure-function relationships can guide the reverse engineering of spider silk to enable the production of superior synthetic fibres.

  6. Dermatologic Diseases in Silk Workers

    Directory of Open Access Journals (Sweden)

    J S Pasricha

    1985-01-01

    Full Text Available A survey of 112 workers of a silk facory near Bangalore, for dermatologic diseases revealed (1 a characteristic wearing off of the medial halves of the distal free edges of the finger nail plates in 10 of the 15 cocoonsorters, (2 maceration of the palms in 58 workers of the boiling and reeling section, and (3 pitted keratolysis of the palms, in 42 workers, also from the boiling and reeling section. There was no clinical evidence of contact dermatitis, and patch tests with the silk thread from the cocoons in 25 workers showed a very mild reaction in 2 workers and a doubtful reaction in another two. In addition, one worker from the skeining section had crisscross superficial fissures on the finger tips caused by friction, two workers had paronychia ′of the fingers and four workers had dermatophytFNx01t fingers webs. As in the previous survey, these workers also had a high incidence of ichthyosis (92 workers and hyperketatosis of the palms (62 workers and soles (110 workers.

  7. Facile and highly efficient approach for the fabrication of multifunctional silk nanofibers containing hydroxyapatite and silver nanoparticles.

    Science.gov (United States)

    Sheikh, Faheem A; Ju, Hyung Woo; Moon, Bo Mi; Park, Hyun Jung; Kim, Jung-Ho; Lee, Ok Joo; Park, Chan Hum

    2014-10-01

    In this study, a good combination consisting of electrospun silk fibroin nanofibers incorporated with high-purity hydroxyapatite (HAp) nanoparticles (NPs) and silver NPs is introduced as antimicrobial for tissue engineering applications. The variable pressure field emission scanning electron microscope results confirmed randomly placed nanofibers are produced with highly dispersed HAp and silver NPs in nanofibers after electrospinning. The X-ray diffraction results demonstrated crystalline features of each of the three components used for electrospinning. Moreover, the TEM-EDS analysis confirmed the presence and chemical nature of each component over individual silk nanofiber. The FT-IR analyses was used confirm the different vibration modes caused due to functional groups present in silk fibroin, Hap, and silver NPs. The obtained nanofibers were checked for antimicrobial activity by using two model organisms Escherichia coli and Staphylococcus aureus. Subsequently, the antimicrobial tests have indicated that prepared nanofibers do possess good bactericidal activity. The ability of N,N-dimethylformamide and silk fibroin used to reduce silver nitrate into silver metal was evaluated using MTT assay. The nanofibers were grown in presence of NIH 3T3 fibroblasts, which revealed toxic behavior to fibroblasts at higher concentrations of silver nitrate used in this study. Furthermore, cell attachment studies on nanofibers for 3 and 12 days of incubation time were minutely observed and correlated with the results of MTT assay. The reported results confirmed the high amounts of silver nitrate can lead to toxic effects on viability of fibroblasts and had bad effect in cell attachment. © 2013 Wiley Periodicals, Inc.

  8. Biofunctionalization of scaffold material with nano-scaled diamond particles physisorbed with angiogenic factors enhances vessel growth after implantation.

    Science.gov (United States)

    Schimke, Magdalena M; Stigler, Robert; Wu, Xujun; Waag, Thilo; Buschmann, Peter; Kern, Johann; Untergasser, Gerold; Rasse, Michael; Steinmüller-Nethl, Doris; Krueger, Anke; Lepperdinger, Günter

    2016-04-01

    Biofunctionalized scaffold facilitates complete healing of large defects. Biological constraints are induction and ingrowth of vessels. Angiogenic growth factors such as vascular endothelial growth factor or angiopoietin-1 can be bound to nano-scaled diamond particles. Corresponding bioactivities need to be examined after biofunctionalization. We therefore determined the physisorptive capacity of distinctly manufactured, differently sized nDP and the corresponding activities of bound factors. The properties of biofunctionalized nDPs were investigated on cultivated human mesenchymal stem cells and on the developing chicken embryo chorio-allantoic membrane. Eventually porous bone substitution material was coated with nDP to generate an interface that allows biofactor physisorption. Angiopoietin-1 was applied shortly before scaffold implantation into an osseous defect in sheep calvaria. Biofunctionalized scaffolds exhibited significantly increased rates of angiogenesis already one month after implantation. Conclusively, nDP can be used to ease functionalization of synthetic biomaterials. With the advances in nanotechnology, many nano-sized materials have been used in the biomedical field. This is also true for nano-diamond particles (nDP). In this article, the authors investigated the physical properties of functionalized nano-diamond particles in both in-vitro and in-vivo settings. The positive findings would help improve understanding of these nanomaterials in regenerative medicine. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. 3D surface topography study of the biofunctionalized nanocrystalline Ti–6Zr–4Nb/Ca–P

    International Nuclear Information System (INIS)

    Jakubowicz, J.; Adamek, G.; Jurczyk, M.U.; Jurczyk, M.

    2012-01-01

    In this work surface of the sintered Ti–6Zr–4Nb nanocrystalline alloy was electrochemically biofunctionalized. The porous surface was produced by anodic oxidation in 1 M H 3 PO 4 + 2%HF electrolyte at 10 V for 30 min. Next the calcium–phosphate (Ca–P) layer was deposited, onto the formed porous surface, using cathodic potential − 5 V kept for 60 min in 0.042 M Ca(NO 3 ) 2 + 0.025 M (NH 4 ) 2 HPO 4 + 0.1 M HCl electrolyte. The deposited Ca–P layer anchored in the pores. The biofunctionalized surface was studied by XRD, SEM and EDS. In vitro tests culture of normal human osteoblast (NHOst) cells showed very good cells proliferation, colonization and multilayering. Using optical profiler, roughness and hybrid 3D surface topography parameters were estimated. Correlation between surface composition, morphology, roughness and biocompatibility results was done. It has been shown by us that surface with appropriate chemical composition and topography, after combined electrochemical anodic and cathodic surface treatment, supports osteoblast adhesion and proliferation. 3D topography measurements using optical profiler play a key role in the biomaterials surface analysis. - Highlights: ► Nanocrystalline Ti–6Zr–4Nb/Ca–P material was produced for hard tissue implant applications. ► Calcium-phosphate results in surface biofunctionalization. ► The biofunctionalized surface shows good in-vitro behavior.

  10. Manufacture and Drug Delivery Applications of Silk Nanoparticles.

    Science.gov (United States)

    Wongpinyochit, Thidarat; Johnston, Blair F; Seib, F Philipp

    2016-10-08

    Silk is a promising biopolymer for biomedical and pharmaceutical applications due to its outstanding mechanical properties, biocompatibility and biodegradability, as well its ability to protect and subsequently release its payload in response to a trigger. While silk can be formulated into various material formats, silk nanoparticles are emerging as promising drug delivery systems. Therefore, this article covers the procedures for reverse engineering silk cocoons to yield a regenerated silk solution that can be used to generate stable silk nanoparticles. These nanoparticles are subsequently characterized, drug loaded and explored as a potential anticancer drug delivery system. Briefly, silk cocoons are reverse engineered first by degumming the cocoons, followed by silk dissolution and clean up, to yield an aqueous silk solution. Next, the regenerated silk solution is subjected to nanoprecipitation to yield silk nanoparticles - a simple but powerful method that generates uniform nanoparticles. The silk nanoparticles are characterized according to their size, zeta potential, morphology and stability in aqueous media, as well as their ability to entrap a chemotherapeutic payload and kill human breast cancer cells. Overall, the described methodology yields uniform silk nanoparticles that can be readily explored for a myriad of applications, including their use as a potential nanomedicine.

  11. Biomolecule screening for efficient attachment of biofunctionalized microparticles to the zona pellucida of mammalian oocytes and embryos.

    Science.gov (United States)

    Novo, Sergio; Ibáñez, Elena; Barrios, Leonardo; Castell, Onofre; Nogués, Carme

    2013-10-01

    Individual tagging of oocytes and embryos through the attachment of micrometer-sized polysilicon barcodes to their zona pellucida (ZP) is a promising approach to ensure their correct identification and traceability in human assisted reproduction and in animal production programs. To provide barcodes with the capacity of binding to the ZP, they must be first biofunctionalized with a biomolecule capable of binding to the ZP of both oocytes and embryos. The aim of this work was to select, among an anti-ZP2 antibody and the two lectins wheat germ agglutinin (WGA) and phytohemagglutinin-L, the most optimal biomolecule for the eventual biofunctionalization of barcodes, using mouse oocytes and embryos and commercially available microspheres as a model. Despite the anti-ZP2 antibody showed the highest number of binding sites onto the ZP surface, as determined by field emission scanning electron microscopy, the binding of anti-ZP2-biofunctionalized microspheres to the ZP of cultured oocytes and embryos was less robust and less stable than the binding of lectin-biofunctionalized ones. WGA proved to be, among the three candidates tested, the most appropriate biomolecule to biofunctionalize microparticles with the aim to attach them to the ZP of both oocytes and embryos and to maintain them attached through oocyte activation (zona reaction) and in vitro culture up to the blastocyst stage. As saccharides recognized by WGA are highly abundant in the ZP of most mammalian species, WGA-biofuncionalized microparticles would be able to attach to the ZP of oocytes/embryos of species other than the mouse, such as humans and farm animals.

  12. Silk fibers and silk-producing organs of Harpactea rubicunda (C. L. Koch 1838) (Araneae, Dysderidae).

    Science.gov (United States)

    Hajer, Jaromír; Malý, Jan; Reháková, Dana

    2013-01-01

    Scanning electron microscopy and atomic force microscopy were used to study the silk spinning apparatus and silks of Harpactea rubicunda spiders. Three types of silk secretions that are produced by three kinds of silk spinning glands (ampullate, piriform, and pseudaciniform) and released through three types of spigots, were confirmed for both adult and juvenile spiders. Silk secretions for the construction of spider webs for shelter or retreat are produced by the pseudaciniform silk glands. Silk secretions that are released from spigots in the course of web construction are not processed by the legs during the subsequent process of hardening. Pairs of nanofibril bundles seemed to be part of the basic microarchitecture of the web silk fibers as revealed by AFM. These fiber bundles frequently not only overlap one another, but occasionally also interweave. This structural variability may strengthen the spider web. High-resolution AFM scans of individual nanofibrils show a distinctly segmented nanostructure. Each globular segment is ∼30-40 nm long along the longitudinal axis of the fiber, and resembles a nanosegment of artificial fibroin described by Perez-Rigueiro et al. (2007). Copyright © 2012 Wiley Periodicals, Inc.

  13. Radiation degradation of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Wachiraporn Pewlong; Boonya Sudatis [Office of Atomic Energy for Peace, Bangkok (Thailand); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-09-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated in the dose range up to 2500 kGy using an electron beam accelerator to apply the radiation degradation technique as a means to solubilize fibroin. The tensile strength of irradiated fibroin fiber decreased with increasing dose and the presence of oxygen in the irradiation atmosphere enhanced the degradation. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: calcium chloride solution (CaCl{sub 2}/C{sub 2}H{sub 5}OH/H{sub 2}O = 1 : 2 : 8 in mole ratio), hydrochloric acid (0.5N) and distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water-soluble protein was extracted by distilled water. (author)

  14. Radiation degradation of silk protein

    International Nuclear Information System (INIS)

    Pewlong, W.; Sudatis, B.; Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu

    2000-01-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl 2 /C 2 H 5 OH/H 2 O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  15. Radiation degradation of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Pewlong, W; Sudatis, B [Office of Atomic Energy for Peace, Bangkok (Thailand); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl{sub 2}/C{sub 2}H{sub 5}OH/H{sub 2}O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  16. Facts and myths of antibacterial properties of silk.

    Science.gov (United States)

    Kaur, Jasjeet; Rajkhowa, Rangam; Afrin, Tarannum; Tsuzuki, Takuya; Wang, Xungai

    2014-03-01

    Silk cocoons provide protection to silkworm from biotic and abiotic hazards during the immobile pupal phase of the lifecycle of silkworms. Protection is particularly important for the wild silk cocoons reared in an open and harsh environment. To understand whether some of the cocoon components resist growth of microorganisms, in vitro studies were performed using gram negative bacteria Escherichia coli (E. coli) to investigate antibacterial properties of silk fiber, silk gum, and calcium oxalate crystals embedded inside some cocoons. The results show that the previously reported antibacterial properties of silk cocoons are actually due to residues of chemicals used to isolate/purify cocoon elements, and properly isolated silk fiber, gum, and embedded crystals free from such residues do not have inherent resistance to E. coli. This study removes the uncertainty created by previous studies over the presence of antibacterial properties of silk cocoons, particularly the silk gum and sericin. Copyright © 2013 Wiley Periodicals, Inc.

  17. Structural analysis and application to biomaterials of the silk fibroins

    International Nuclear Information System (INIS)

    Nakazawa, Yasumoto

    2010-01-01

    Silk fibroin from Bombyx mori silkworm has outstanding mechanical properties despite being spun from aqueous solution. I have clarified two distinct structures in the solid state; silk I and silk II, which mean the structures before and after spinning, by using solid state NMR. Moreover, I have been developing several kinds of biomaterials, such as bone regeneration materials and vascular grafts. In this paper, I present two topics: one is the structural analyses of the silk fibroin in detail, the other is applications of silk fibroins to tissue engineering. In the case of vascular regeneration, I have developed the small diameter vascular grafts made by silk fibroins. The new grafts from silk fibroins have good patency, and these grafts were commonly covered with cells and platelets at 4 weeks after implantation. For bone tissue engineering, I performed structural analyses of a new silk-like peptide, E n (AGSGAG) 4 , in order to consider the molecular design of biomaterials for bone regeneration. (author)

  18. Protective effects of flavonoids from corn silk on oxidative stress ...

    African Journals Online (AJOL)

    Protective effects of flavonoids from corn silk on oxidative stress induced by ... The present study aims at exploring the effects of flavonoids from corn silk (FCS) on oxidative stress induced by exhaustive exercise in mice. ... from 32 Countries:.

  19. Electrospun polymeric nanofibers for transdermal drug delivery

    Directory of Open Access Journals (Sweden)

    Mahya Rahmani

    2017-04-01

    Full Text Available Conventional transdermal drug delivery systems (TDDS have been designed for drug delivery through the skin. These systems use the permeability property of stratum corneum, the outermost surface layer of the skin. Applying polymeric micro and nanofibers in drug delivery has recently attracted great attention and the electrospinning technique is the preferred method for polymeric micro-nanofibers fabrication with a great potential for drug delivery. More studies in the field of nanofibers containing drug are divided two categories: first, preparation and characterization of nanofibers containing drug and second, investigation of their therapeutic applications. Drugs used in electrospun nanofibers can be categorized into three main groups, including antibiotics and antimicrobial agents, anti-inflammatory agents and vitamins with therapeutic applications. In this paper, we review the application of electrospun polymeric scaffolds in TDDS and also introduce several pharmaceutical and therapeutic agents which have been used in polymer nanofibrous patches.

  20. Electrospun Nanofibrous Materials for Neural Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Yee-Shuan Lee

    2011-02-01

    Full Text Available The use of biomaterials processed by the electrospinning technique has gained considerable interest for neural tissue engineering applications. The tissue engineering strategy is to facilitate the regrowth of nerves by combining an appropriate cell type with the electrospun scaffold. Electrospinning can generate fibrous meshes having fiber diameter dimensions at the nanoscale and these fibers can be nonwoven or oriented to facilitate neurite extension via contact guidance. This article reviews studies evaluating the effect of the scaffold’s architectural features such as fiber diameter and orientation on neural cell function and neurite extension. Electrospun meshes made of natural polymers, proteins and compositions having electrical activity in order to enhance neural cell function are also discussed.

  1. Measuring Electrospun Nanofibre Diameter: a Novel Approach

    International Nuclear Information System (INIS)

    Ziabari, M.; Mottaghitalab, V.; Haghi, A. K.; McGovern, S. T.

    2008-01-01

    A new method based on image analysis for electrospun nanofibre diameter measurement is presented. First, the SEM micrograph of the nanofibre web obtained by electrospinning process is converted to binary image using local thresholding method. In the next step, skeleton and distance transformed image are generated. Then, the intersection points which bring about untrue measurements are identified and removed from the skeleton. Finally, the resulting skeleton and distance transformed image are used to determine fibre diameter. The method is evaluated by a simulated image with known characteristics generated by ?-randomness procedure. The results indicate that this approach is successful in making fast, accurate automated measurements of electrospun fibre diameters. (cross-disciplinary physics and related areas of science and technology)

  2. Quantitative analysis of allantoin in Iranian corn silk

    OpenAIRE

    E. Khanpour*; M. Modarresi

    2017-01-01

    Background and objectives: Zea mays is cultivated in different parts of Iran and corn silk is used in traditional medicine. Allantoin is one of the major compounds in corn silk. The purpose of this research was the quantitatve analysis of allantoin in corn silks belonging to several regions of Iran. Methods: The samples of corn silk were prepared from three provinces of Iran (Kermanshah, Fars and Razavi Khorasan). The dried plant materials were infused in boiling distilled water with a temper...

  3. Electrospun nanofiber scaffolds: engineering soft tissues

    International Nuclear Information System (INIS)

    Kumbar, S G; Nukavarapu, S P; Laurencin, C T; James, R

    2008-01-01

    Electrospinning has emerged to be a simple, elegant and scalable technique to fabricate polymeric nanofibers. Pure polymers as well as blends and composites of both natural and synthetics have been successfully electrospun into nanofiber matrices. Physiochemical properties of nanofiber matrices can be controlled by manipulating electrospinning parameters to meet the requirements of a specific application. Such efforts include the fabrication of fiber matrices containing nanofibers, microfibers, combination of nano-microfibers and also different fiber orientation/alignments. Polymeric nanofiber matrices have been extensively investigated for diversified uses such as filtration, barrier fabrics, wipes, personal care, biomedical and pharmaceutical applications. Recently electrospun nanofiber matrices have gained a lot of attention, and are being explored as scaffolds in tissue engineering due to their properties that can modulate cellular behavior. Electrospun nanofiber matrices show morphological similarities to the natural extra-cellular matrix (ECM), characterized by ultrafine continuous fibers, high surface-to-volume ratio, high porosity and variable pore-size distribution. Efforts have been made to modify nanofiber surfaces with several bioactive molecules to provide cells with the necessary chemical cues and a more in vivo like environment. The current paper provides an overlook on such efforts in designing nanofiber matrices as scaffolds in the regeneration of various soft tissues including skin, blood vessel, tendon/ligament, cardiac patch, nerve and skeletal muscle

  4. Electrospun nanofiber scaffolds: engineering soft tissues

    Energy Technology Data Exchange (ETDEWEB)

    Kumbar, S G; Nukavarapu, S P; Laurencin, C T [Department of Orthopaedic Surgery, University of Virginia, VA 22908 (United States); James, R [Department of Biomedical Engineering, University of Virginia, VA 22908 (United States)], E-mail: laurencin@virginia.edu

    2008-09-01

    Electrospinning has emerged to be a simple, elegant and scalable technique to fabricate polymeric nanofibers. Pure polymers as well as blends and composites of both natural and synthetics have been successfully electrospun into nanofiber matrices. Physiochemical properties of nanofiber matrices can be controlled by manipulating electrospinning parameters to meet the requirements of a specific application. Such efforts include the fabrication of fiber matrices containing nanofibers, microfibers, combination of nano-microfibers and also different fiber orientation/alignments. Polymeric nanofiber matrices have been extensively investigated for diversified uses such as filtration, barrier fabrics, wipes, personal care, biomedical and pharmaceutical applications. Recently electrospun nanofiber matrices have gained a lot of attention, and are being explored as scaffolds in tissue engineering due to their properties that can modulate cellular behavior. Electrospun nanofiber matrices show morphological similarities to the natural extra-cellular matrix (ECM), characterized by ultrafine continuous fibers, high surface-to-volume ratio, high porosity and variable pore-size distribution. Efforts have been made to modify nanofiber surfaces with several bioactive molecules to provide cells with the necessary chemical cues and a more in vivo like environment. The current paper provides an overlook on such efforts in designing nanofiber matrices as scaffolds in the regeneration of various soft tissues including skin, blood vessel, tendon/ligament, cardiac patch, nerve and skeletal muscle.

  5. Waveguiding properties of individual electrospun polymer nanofibers

    Science.gov (United States)

    Ishii, Yuya; Kaminose, Ryohei; Fukuda, Mitsuo

    2013-09-01

    Optical circuits are needed to achieve high-speed, high-capacity information processing. An optical waveguide is an essential element in optical circuits. Electrospun polymer fibers have diameters in the nanometer range and high aspect ratios, so they are prime candidates for small waveguides. In this work, we fabricate uniform electrospun polymer nanofibers and characterize their optical waveguiding properties. Poly(methyl methacrylate) (PMMA) solutions of different concentration that contain a small amount of Nile Blue A perchlorate (NBA) are electrospun. Uniform PMMA/NBA nanofibers are obtained from the 10 wt% solution. The fibers are covered with transparent cladding and their ends cut vertically. A laser beam with a wavelength of 533 nm is irradiated onto the fiber from the direction vertical to the fiber axis so that it scans along the fiber. Photoluminescence (PL) at the end face of individual fibers is then measured. The PL intensity decreases with increasing distance (d) between the end face of a fiber and irradiating point of the laser beam as ~exp(-αd) with a loss coefficient (α). Measurements of five individual fibers reveal α is in the range of 17-75 cm-1.

  6. Biocompatible electrospun polymer blends for biomedical applications.

    Science.gov (United States)

    Munj, Hrishikesh Ramesh; Nelson, M Tyler; Karandikar, Prathamesh Sadanand; Lannutti, John Joseph; Tomasko, David Lane

    2014-10-01

    Blends of natural and synthetic polymers have received considerable attention as biomaterials due to the potential to optimize both mechanical and bioactive properties. Electrospinning of biocompatible polymers is an efficient method producing biomimetic topographies suited to various applications. In the ultimate application, electrospun scaffolds must also incorporate drug/protein delivery for effective cell growth and tissue repair. This study explored the suitability of a ternary Polymethylmethacrylate-Polycaprolactone-gelatin blend in the preparation of electrospun scaffolds for biomedical applications. Tuning the blend composition allows control over scaffold mechanical properties and degradation rate. Significant improvements were observed in the mechanical properties of the blend compared with the individual components. In order to study drug delivery potential, triblends were impregnated with the model compound Rhodamine-B using sub/supercritical CO₂ infusion under benign conditions. Results show significantly distinct release profiles of the impregnated dye from the triblends. Specific factors such as porosity, degradation rate, stress relaxation, dye-polymer interactions, play key roles in impregnation and release. Each polymer component of the triblends shows distinct behavior during impregnation and release process. This affects the aforementioned factors and the release profiles of the dye. Careful control over blend composition and infusion conditions creates the flexibility needed to produce biocompatible electrospun scaffolds for a variety of biomedical applications. © 2014 Wiley Periodicals, Inc.

  7. Polymorphic regenerated silk fibers assembled through bioinspired spinning.

    Science.gov (United States)

    Ling, Shengjie; Qin, Zhao; Li, Chunmei; Huang, Wenwen; Kaplan, David L; Buehler, Markus J

    2017-11-09

    A variety of artificial spinning methods have been applied to produce regenerated silk fibers; however, how to spin regenerated silk fibers that retain the advantages of natural silks in terms of structural hierarchy and mechanical properties remains challenging. Here, we show a bioinspired approach to spin regenerated silk fibers. First, we develop a nematic silk microfibril solution, highly viscous and stable, by partially dissolving silk fibers into microfibrils. This solution maintains the hierarchical structures in natural silks and serves as spinning dope. It is then spun into regenerated silk fibers by direct extrusion in the air, offering a useful route to generate polymorphic and hierarchical regenerated silk fibers with physical properties beyond natural fiber construction. The materials maintain the structural hierarchy and mechanical properties of natural silks, including a modulus of 11 ± 4 GPa, even higher than natural spider silk. It can further be functionalized with a conductive silk/carbon nanotube coating, responsive to changes in humidity and temperature.

  8. Hybrid Silk Fibers Dry-Spun from Regenerated Silk Fibroin/Graphene Oxide Aqueous Solutions.

    Science.gov (United States)

    Zhang, Chao; Zhang, Yaopeng; Shao, Huili; Hu, Xuechao

    2016-02-10

    Regenerated silk fibroin (RSF)/graphene oxide (GO) hybrid silk fibers were dry-spun from a mixed dope of GO suspension and RSF aqueous solution. It was observed that the presence of GO greatly affect the viscosity of RSF solution. The RSF/GO hybrid fibers showed from FTIR result lower β-sheet content compared to that of pure RSF fibers. The result of synchrotron radiation wide-angle X-ray diffraction showed that the addition of GO confined the crystallization of silk fibroin (SF) leading to the decrease of crystallinity, smaller crystallite size, and new formation of interphase zones in the artificial silks. Synchrotron radiation small-angle X-ray scattering also proved that GO sheets in the hybrid silks and blended solutions were coated with a certain thickness of interphase zones due to the complex interaction between the two components. A low addition of GO, together with the mesophase zones formed between GO and RSF, enhanced the mechanical properties of hybrid fibers. The highest breaking stress of the hybrid fibers reached 435.5 ± 71.6 MPa, 23% improvement in comparison to that of degummed silk and 72% larger than that of pure RSF silk fiber. The hybrid RSF/GO materials with good biocompatibility and enhanced mechanical properties may have potential applications in tissue engineering, bioelectronic devices, or energy storage.

  9. Bio-functionalized silver nanoparticles for selective colorimetric sensing of toxic metal ions and antimicrobial studies

    Science.gov (United States)

    Vinod Kumar, V.; Anbarasan, S.; Christena, Lawrence Rene; SaiSubramanian, Nagarajan; Philip Anthony, Savarimuthu

    2014-08-01

    Hibiscus Sabdariffa (Gongura) plant extracts (leaves (HL) and stem (HS) were used for the first time in the green synthesis of bio-functionalized silver nanoparticles (AgNPs). The bio-functionality of AgNPs has been successfully utilized for selective colorimetric sensing of potentially health and environmentally hazardous Hg2+, Cd2+ and Pb2+ metal ions at ppm level in aqueous solution. Importantly, clearly distinguishable colour for all three metal ions was observed. The influence of extract preparation condition and pH were also explored on the formation of AgNPs. Both selectivity and sensitivity differed for AgNPs synthesized from different parts of the plant. Direct correlation between the stability of green synthesized AgNPs at different pH and its antibacterial effects has been established. The selective colorimetric sensing of toxic metal ions and antimicrobial effect of green synthesized AgNPs demonstrated the multifunctional applications of green nanotechnology.

  10. Biofunctionalized Zinc Oxide Field Effect Transistors for Selective Sensing of Riboflavin with Current Modulation

    Directory of Open Access Journals (Sweden)

    Morley O. Stone

    2011-06-01

    Full Text Available Zinc oxide field effect transistors (ZnO-FET, covalently functionalized with single stranded DNA aptamers, provide a highly selective platform for label-free small molecule sensing. The nanostructured surface morphology of ZnO provides high sensitivity and room temperature deposition allows for a wide array of substrate types. Herein we demonstrate the selective detection of riboflavin down to the pM level in aqueous solution using the negative electrical current response of the ZnO-FET by covalently attaching a riboflavin binding aptamer to the surface. The response of the biofunctionalized ZnO-FET was tuned by attaching a redox tag (ferrocene to the 3’ terminus of the aptamer, resulting in positive current modulation upon exposure to riboflavin down to pM levels.

  11. Silk: a potential medium for tissue engineering.

    Science.gov (United States)

    Sobajo, Cassandra; Behzad, Farhad; Yuan, Xue-Feng; Bayat, Ardeshir

    2008-01-01

    Human skin is a complex bilayered organ that serves as a protective barrier against the environment. The loss of integrity of skin by traumatic experiences such as burns and ulcers may result in considerable disability or ultimately death. Therefore, in skin injuries, adequate dermal substitutes are among primary care targets, aimed at replacing the structural and functional properties of native skin. To date, there are very few single application tissue-engineered dermal constructs fulfilling this criterion. Silk produced by the domestic silkworm, Bombyx mori, has a long history of use in medicine. It has recently been increasingly investigated as a promising biomaterial for dermal constructs. Silk contains 2 fibrous proteins, sericin and fibroin. Each one exhibits unique mechanical and biological properties. Comprehensive review of randomized-controlled trials investigating current dermal constructs and the structures and properties of silk-based constructs on wound healing. This review revealed that silk-fibroin is regarded as the most promising biomaterial, providing options for the construction of tissue-engineered skin. The research available indicates that silk fibroin is a suitable biomaterial scaffold for the provision of adequate dermal constructs.

  12. An algorithm for three-dimensional Monte-Carlo simulation of charge distribution at biofunctionalized surfaces

    KAUST Repository

    Bulyha, Alena

    2011-01-01

    In this work, a Monte-Carlo algorithm in the constant-voltage ensemble for the calculation of 3d charge concentrations at charged surfaces functionalized with biomolecules is presented. The motivation for this work is the theoretical understanding of biofunctionalized surfaces in nanowire field-effect biosensors (BioFETs). This work provides the simulation capability for the boundary layer that is crucial in the detection mechanism of these sensors; slight changes in the charge concentration in the boundary layer upon binding of analyte molecules modulate the conductance of nanowire transducers. The simulation of biofunctionalized surfaces poses special requirements on the Monte-Carlo simulations and these are addressed by the algorithm. The constant-voltage ensemble enables us to include the right boundary conditions; the dna strands can be rotated with respect to the surface; and several molecules can be placed in a single simulation box to achieve good statistics in the case of low ionic concentrations relevant in experiments. Simulation results are presented for the leading example of surfaces functionalized with pna and with single- and double-stranded dna in a sodium-chloride electrolyte. These quantitative results make it possible to quantify the screening of the biomolecule charge due to the counter-ions around the biomolecules and the electrical double layer. The resulting concentration profiles show a three-layer structure and non-trivial interactions between the electric double layer and the counter-ions. The numerical results are also important as a reference for the development of simpler screening models. © 2011 The Royal Society of Chemistry.

  13. Bio-hybrid silk fibroin/calcium phosphate/PLGA nanocomposite scaffold to control the delivery of vascular endothelial growth factor

    International Nuclear Information System (INIS)

    Farokhi, Mehdi; Mottaghitalab, Fatemeh; Shokrgozar, Mohammad Ali; Ai, Jafar; Hadjati, Jamshid; Azami, Mahmoud

    2014-01-01

    This study investigated the efficacy of bio-hybrid silk fibroin/Calcium phosphate/PLGA nanocomposite scaffold as vascular endothelial growth factor (VEGF) delivery system. The scaffold was fabricated using freeze-drying and electrospinning. Here, we highlight the structural changes of the scaffold using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and differential scanning calorimetry (DSC). The uniform dispersion of calcium phosohate (CaP) powder within silk fibroin (SF) solution was also confirmed using Zeta potential analysis. Moreover, good biocompatibility of osteoblast cells next to the scaffold was approved by cell adhesion, proliferation and alkaline phosphatase production. The release profile of VEGF during 28 days has established the efficacy of the scaffold as a sustained delivery system. The bioactivity of the released VEGF was maintained about 83%. The histology analysis has shown that the new bone tissue formation happened in the defected site after 10 weeks of implantation. Generally, our data showed that the fabricated scaffold could be considered as an effective scaffold for bone tissue engineering applications. - Highlights: • Silk fibroin/calcium phosphate/PLGA scaffold was successfully fabricated using freeze-drying and electrospinning. • The scaffold could control the release of VEGF during 28 days. • The bioactivity of electrospun VEGF was above 80%. • VEGF loaded scaffold could induce bone regeneration after 10 weeks in rabbit

  14. Bio-hybrid silk fibroin/calcium phosphate/PLGA nanocomposite scaffold to control the delivery of vascular endothelial growth factor

    Energy Technology Data Exchange (ETDEWEB)

    Farokhi, Mehdi, E-mail: mehdi13294@yahoo.com [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mottaghitalab, Fatemeh, E-mail: fatemeh.motaghi@gmail.com [Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University (TMU), Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali, E-mail: mashokrgozar@pasteur.ac.ir [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Ai, Jafar, E-mail: jafar_ai@tums.ac.ir [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hadjati, Jamshid; Azami, Mahmoud [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2014-02-01

    This study investigated the efficacy of bio-hybrid silk fibroin/Calcium phosphate/PLGA nanocomposite scaffold as vascular endothelial growth factor (VEGF) delivery system. The scaffold was fabricated using freeze-drying and electrospinning. Here, we highlight the structural changes of the scaffold using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and differential scanning calorimetry (DSC). The uniform dispersion of calcium phosohate (CaP) powder within silk fibroin (SF) solution was also confirmed using Zeta potential analysis. Moreover, good biocompatibility of osteoblast cells next to the scaffold was approved by cell adhesion, proliferation and alkaline phosphatase production. The release profile of VEGF during 28 days has established the efficacy of the scaffold as a sustained delivery system. The bioactivity of the released VEGF was maintained about 83%. The histology analysis has shown that the new bone tissue formation happened in the defected site after 10 weeks of implantation. Generally, our data showed that the fabricated scaffold could be considered as an effective scaffold for bone tissue engineering applications. - Highlights: • Silk fibroin/calcium phosphate/PLGA scaffold was successfully fabricated using freeze-drying and electrospinning. • The scaffold could control the release of VEGF during 28 days. • The bioactivity of electrospun VEGF was above 80%. • VEGF loaded scaffold could induce bone regeneration after 10 weeks in rabbit.

  15. Effect of degumming ph value on electrospining of silk fibroin

    Directory of Open Access Journals (Sweden)

    Lu Shen-Zhou

    2014-01-01

    Full Text Available Regenerated silk fibroin fibers show properties dependent on the molecular weight of fibroin. The cocoon-degumming approaches had great impact on the degradation of silk fibroin. The effect of degumming pH value to electrospining of fibroin was studied in this paper. The viscosity and molecular weight of regenerated silk fibroin were studied using rheometer and gel electrophoresis. The results showed that the weaker the alkalinity of degumming reagent, there was the milder the effect on silk fibroin molecular. The fibroin fibers can be prepared by electrospining with low concentration of regenerated silk fibroin solution.

  16. Atomistic model of the spider silk nanostructure

    Science.gov (United States)

    Keten, Sinan; Buehler, Markus J.

    2010-04-01

    Spider silk is an ultrastrong and extensible self-assembling biopolymer that outperforms the mechanical characteristics of many synthetic materials including steel. Here we report atomic-level structures that represent aggregates of MaSp1 proteins from the N. Clavipes silk sequence based on a bottom-up computational approach using replica exchange molecular dynamics. We discover that poly-alanine regions predominantly form distinct and orderly beta-sheet crystal domains while disorderly structures are formed by poly-glycine repeats, resembling 31-helices. These could be the molecular source of the large semicrystalline fraction observed in silks, and also form the basis of the so-called "prestretched" molecular configuration. Our structures are validated against experimental data based on dihedral angle pair calculations presented in Ramachandran plots, alpha-carbon atomic distances, as well as secondary structure content.

  17. Silk industry and carbon footprint mitigation

    Science.gov (United States)

    Giacomin, A. M.; Garcia, J. B., Jr.; Zonatti, W. F.; Silva-Santos, M. C.; Laktim, M. C.; Baruque-Ramos, J.

    2017-10-01

    Currently there is a concern with issues related to sustainability and more conscious consumption habits. The carbon footprint measures the total amount of greenhouse gas (GHG) emissions produced directly and indirectly by human activities and is usually expressed in tonnes of carbon dioxide (CO2) equivalents. The present study takes into account data collected in scientific literature regarding the carbon footprint, garments produced with silk fiber and the role of mulberry as a CO2 mitigation tool. There is an indication of a positive correlation between silk garments and carbon footprint mitigation when computed the cultivation of mulberry trees in this calculation. A field of them mitigates CO2 equivalents in a proportion of 735 times the weight of the produced silk fiber by the mulberry cultivated area. At the same time, additional researches are needed in order to identify and evaluate methods to advertise this positive correlation in order to contribute to a more sustainable fashion industry.

  18. Silk fibroin in tissue engineering.

    Science.gov (United States)

    Kasoju, Naresh; Bora, Utpal

    2012-07-01

    Tissue engineering (TE) is a multidisciplinary field that aims at the in vitro engineering of tissues and organs by integrating science and technology of cells, materials and biochemical factors. Mimicking the natural extracellular matrix is one of the critical and challenging technological barriers, for which scaffold engineering has become a prime focus of research within the field of TE. Amongst the variety of materials tested, silk fibroin (SF) is increasingly being recognized as a promising material for scaffold fabrication. Ease of processing, excellent biocompatibility, remarkable mechanical properties and tailorable degradability of SF has been explored for fabrication of various articles such as films, porous matrices, hydrogels, nonwoven mats, etc., and has been investigated for use in various TE applications, including bone, tendon, ligament, cartilage, skin, liver, trachea, nerve, cornea, eardrum, dental, bladder, etc. The current review extensively covers the progress made in the SF-based in vitro engineering and regeneration of various human tissues and identifies opportunities for further development of this field. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Multifunctional silk-heparin biomaterials for vascular tissue engineering applications

    Science.gov (United States)

    Seib, F. Philipp; Herklotz, Manuela; Burke, Kelly A.; Maitz, Manfred F.; Werner, Carsten; Kaplan, David L.

    2013-01-01

    Over the past 30 years, silk has been proposed for numerous biomedical applications that go beyond its traditional use as a suture material. Silk sutures are well tolerated in humans, but the use of silk for vascular engineering applications still requires extensive biocompatibility testing. Some studies have indicated a need to modify silk to yield a hemocompatible surface. This study examined the potential of low molecular weight heparin as a material for refining silk properties by acting as a carrier for vascular endothelial growth factor (VEGF) and improving silk hemocompatibility. Heparinized silk showed a controlled VEGF release over 6 days; the released VEGF was bioactive and supported the growth of human endothelial cells. Silk samples were then assessed using a humanized hemocompatibility system that employs whole blood and endothelial cells. The overall thrombogenic response for silk was very low and similar to the clinical reference material polytetrafluoroethylene. Despite an initial inflammatory response to silk, apparent as complement and leukocyte activation, the endothelium was maintained in a resting, anticoagulant state. The low thrombogenic response and the ability to control VEGF release support the further development of silk for vascular applications. PMID:24099708

  20. Variation in Protein Intake Induces Variation in Spider Silk Expression

    Science.gov (United States)

    Blamires, Sean J.; Wu, Chun-Lin; Tso, I-Min

    2012-01-01

    Background It is energetically expensive to synthesize certain amino acids. The proteins (spidroins) of spider major ampullate (MA) silk, MaSp1 and MaSp2, differ in amino acid composition. Glutamine and proline are prevalent in MaSp2 and are expensive to synthesize. Since most orb web spiders express high proline silk they might preferentially attain the amino acids needed for silk from food and shift toward expressing more MaSp1 in their MA silk when starved. Methodology/Principal Findings We fed three spiders; Argiope aetherea, Cyrtophora moluccensis and Leucauge blanda, high protein, low protein or no protein solutions. A. aetherea and L. blanda MA silks are high in proline, while C. moluccesnsis MA silks are low in proline. After 10 days of feeding we determined the amino acid compositions and mechanical properties of each species' MA silk and compared them between species and treatments with pre-treatment samples, accounting for ancestry. We found that the proline and glutamine of A. aetherea and L. blanda silks were affected by protein intake; significantly decreasing under the low and no protein intake treatments. Glutmaine composition in C. moluccensis silk was likewise affected by protein intake. However, the composition of proline in their MA silk was not significantly affected by protein intake. Conclusions Our results suggest that protein limitation induces a shift toward different silk proteins with lower glutamine and/or proline content. Contradictions to the MaSp model lie in the findings that C. moluccensis MA silks did not experience a significant reduction in proline and A. aetherea did not experience a significant reduction in serine on low/no protein. The mechanical properties of the silks could not be explained by a MaSp1 expressional shift. Factors other than MaSp expression, such as the expression of spidroin-like orthologues, may impact on silk amino acid composition and spinning and glandular processes may impact mechanics. PMID:22363691

  1. Regulation of Silk Genes by Hox and Homeodomain Proteins in the Terminal Differentiated Silk Gland of the Silkworm Bombyx mori

    Science.gov (United States)

    Takiya, Shigeharu; Tsubota, Takuya; Kimoto, Mai

    2016-01-01

    The silk gland of the silkworm Bombyx mori is a long tubular organ that is divided into several subparts along its anteroposterior (AP) axis. As a trait of terminal differentiation of the silk gland, several silk protein genes are expressed with unique regional specificities. Most of the Hox and some of the homeobox genes are also expressed in the differentiated silk gland with regional specificities. The expression patterns of Hox genes in the silk gland roughly correspond to those in embryogenesis showing “colinearity”. The central Hox class protein Antennapedia (Antp) directly regulates the expression of several middle silk gland–specific silk genes, whereas the Lin-1/Isl-1/Mec3 (LIM)-homeodomain transcriptional factor Arrowhead (Awh) regulates the expression of posterior silk gland–specific genes for silk fiber proteins. We summarize our results and discuss the usefulness of the silk gland of Bombyx mori for analyzing the function of Hox genes. Further analyses of the regulatory mechanisms underlying the region-specific expression of silk genes will provide novel insights into the molecular bases for target-gene selection and regulation by Hox and homeodomain proteins. PMID:29615585

  2. Regulation of Silk Genes by Hox and Homeodomain Proteins in the Terminal Differentiated Silk Gland of the Silkworm Bombyx mori

    Directory of Open Access Journals (Sweden)

    Shigeharu Takiya

    2016-05-01

    Full Text Available The silk gland of the silkworm Bombyx mori is a long tubular organ that is divided into several subparts along its anteroposterior (AP axis. As a trait of terminal differentiation of the silk gland, several silk protein genes are expressed with unique regional specificities. Most of the Hox and some of the homeobox genes are also expressed in the differentiated silk gland with regional specificities. The expression patterns of Hox genes in the silk gland roughly correspond to those in embryogenesis showing “colinearity”. The central Hox class protein Antennapedia (Antp directly regulates the expression of several middle silk gland–specific silk genes, whereas the Lin-1/Isl-1/Mec3 (LIM-homeodomain transcriptional factor Arrowhead (Awh regulates the expression of posterior silk gland–specific genes for silk fiber proteins. We summarize our results and discuss the usefulness of the silk gland of Bombyx mori for analyzing the function of Hox genes. Further analyses of the regulatory mechanisms underlying the region-specific expression of silk genes will provide novel insights into the molecular bases for target-gene selection and regulation by Hox and homeodomain proteins.

  3. 21 CFR 184.1262 - Corn silk and corn silk extract.

    Science.gov (United States)

    2010-04-01

    ... specific limitations: Category of food Maximum level of use in food (as served) 1 Functional use Baked... chapter 10 Do. Soft candy, § 170.3(n)(38) of this chapter 20 Do. All other food categories 4 Do. 1 Parts... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Corn silk and corn silk extract. 184.1262 Section...

  4. Electrospun Nanofibres Containing Antimicrobial Plant Extracts

    Directory of Open Access Journals (Sweden)

    Wanwei Zhang

    2017-02-01

    Full Text Available Over the last 10 years great research interest has been directed toward nanofibrous architectures produced by electrospinning bioactive plant extracts. The resulting structures possess antimicrobial, anti-inflammatory, and anti-oxidant activity, which are attractive for biomedical applications and food industry. This review describes the diverse approaches that have been developed to produce electrospun nanofibres that are able to deliver naturally-derived chemical compounds in a controlled way and to prevent their degradation. The efficacy of those composite nanofibres as wound dressings, scaffolds for tissue engineering, and active food packaging systems will be discussed.

  5. Enzymatically crosslinked silk-hyaluronic acid hydrogels.

    Science.gov (United States)

    Raia, Nicole R; Partlow, Benjamin P; McGill, Meghan; Kimmerling, Erica Palma; Ghezzi, Chiara E; Kaplan, David L

    2017-07-01

    In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Silks produced by insect labial glands

    Czech Academy of Sciences Publication Activity Database

    Sehnal, František; Sutherland, T.

    2008-01-01

    Roč. 2, č. 4 (2008), s. 145-153 ISSN 1933-6896 R&D Projects: GA MŠk ME 907 Institutional research plan: CEZ:AV0Z50070508 Keywords : silk * proteinaceous polymers * alfa-helices Subject RIV: ED - Physiology Impact factor: 0.875, year: 2008 http://www.landesbioscience.com/journals/prion/article/7489

  7. Mud and silk in the dark

    DEFF Research Database (Denmark)

    P. S. Reboleira, Ana Sofia; Enghoff, Henrik

    2016-01-01

    chamber, using the available substrate reinforced by a silken web. We present the detailed ultrastructure of the moulting chamber and silk. It takes five days to build the moulting chamber and between 29 (female) and 35 (male) days to shed the exuviae. The male maturation moult is preceded...

  8. Solubilization of silk protein by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sudatis, Boonya; Pongpat, Suchada [Office of Atomic Energy of Peace, Bangkok (Thailand)

    2002-03-01

    Gamma irradiated silk fibroin at doses of 0, 5, 10, 20, 40, 60, 80, 100, 125, 250, 500, 750 and 1000 kGy were soaked in water for 1 hr. Silk fibroin solubilized percentage was investigated from lost weight of sample (dried at 105{sup 0}C), they were 0, 0, 0.7, 0, 0.11, 0.11, 0, 0.73, 0.77, 4.38, 8.32, 10.22 and 18.52 respectively. It showed that at the higher dose up to 250 kGy had direct effect to solubility, and increased with increasing dose. In addition, silk sericin dissolved 77.76, 82.22, 83.55, 84.31, 86.04, 86.67 and 87.37% after gamma irradiation at the doses of 0, 50, 100, 200, 500, 750 and 1000 kGy respectively. It presents that radiation can cause silk protein, fibroin and sericin dissolve because of their degradation. (author)

  9. Curcumin-functionalized silk biomaterials for anti-aging utility.

    Science.gov (United States)

    Yang, Lei; Zheng, Zhaozhu; Qian, Cheng; Wu, Jianbing; Liu, Yawen; Guo, Shaozhe; Li, Gang; Liu, Meng; Wang, Xiaoqin; Kaplan, David L

    2017-06-15

    Curcumin is a natural antioxidant that is isolated from turmeric (Curcuma longa) and exhibits strong free radical scavenging activity, thus functional for anti-aging. However, poor stability and low solubility of curcumin in aqueous conditions limit its biomedical applications. Previous studies have shown that the anti-oxidation activity of curcumin embedded in silk fibroin films could be well preserved, resulting in the promoted adipogenesis from human mesenchymal stem cells (hMSCs) cultured on the surface of the films. In the present study, curcumin was encapsulated in both silk fibroin films (silk/cur films) and nanoparticles (silk/cur NPs), and their anti-aging effects were compared with free curcumin in solution, with an aim to elucidate the mechanism of anti-aging of silk-associated curcumin and to better serve biomedical applications in the future. The morphology and structure of silk/cur film and silk/cur NP were characterized using SEM, FTIR and DSC, indicating characteristic stable beta-sheet structure formation in the materials. Strong binding of curcumin molecules to the beta-sheet domains of silk fibroin resulted in the slow release of curcumin with well-preserved activity from the materials. For cell aging studies, rat bone marrow mesenchymal stem cells (rBMSCs) were cultured in the presence of free curcumin (FC), silk/cur film and silk/cur NP, and cell proliferation and markers of aging (P53, P16, HSP70 gene expression and β-Galactosidase activity) were examined. The results indicated that cell aging was retarded in all FC, silk/cur NP and silk/cur film samples, with the silk-associated curcumin superior to the FC. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Preparation and characterization of kefiran electrospun nanofibers.

    Science.gov (United States)

    Esnaashari, Seyedeh Sara; Rezaei, Sasan; Mirzaei, Esmaeil; Afshari, Hamed; Rezayat, Seyed Mahdi; Faridi-Majidi, Reza

    2014-09-01

    In this study, we report the first successful production of kefiran nanofibers through electrospinning process using distilled water as solvent. For this purpose, kefiran was extracted from cultured kefir grains, and homogenous kefiran solutions with different concentrations were prepared and then electrospun to obtain uniform nanofibers. The effect of main process parameters, including applied voltage, tip-to-collector distance, and feeding rate, on diameter and morphology of produced nanofibers, was studied. Scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were used to characterize electrospun mats. Rheological behavior of the kefiran solution was evaluated via a cone and plate rheometer too. The results exhibited that diameter of kefiran nanofibers increased with increasing polymer concentration, applied voltage, and polymer feeding rate, while tip-to-collector distance did not have significant effect on nanofiber diameter. ATR-FTIR spectra showed that kefiran has maintained its molecular structure during electrospinning process. Flow curves also demonstrated shear thinning behavior for kefiran solutions. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Flexible all-fiber electrospun supercapacitor

    Science.gov (United States)

    Liu, Xinhua; Naylor Marlow, Max; Cooper, Samuel J.; Song, Bowen; Chen, Xiaolong; Brandon, Nigel P.; Wu, Billy

    2018-04-01

    We present an all-fiber flexible supercapacitor with composite nanofiber electrodes made via electrospinning and an electrospun separator. With the addition of manganese acetylacetonate (MnACAC) to polyacrylonitrile (PAN) as a precursor for the electrospinning process and subsequent heat treatment, the performance of pure PAN supercapacitors was improved from 90 F g-1 to 200 F g-1 (2.5 mV s-1) with possible mass loadings of MnACAC demonstrated as high as 40 wt%. X-ray diffraction measurements showed that after thermal treatment, the MnACAC was converted to MnO, meanwile, the thermal decomposition of MnACAC increased the graphitic degree of the carbonised PAN. Scanning electron microscopy and image processing showed that static electrospinning of pure PAN and PAN-Mn resulted in fiber diameters of 460 nm and 480 nm respectively after carbonisation. Further analysis showed that the fiber orientation exhibited a slight bias which was amplified with the addition of MnACAC. Use of focused ion beam scanning electron microscopy tomography also showed that MnO particles were evenly distributed through the fiber at low MnACAC concentrations, while at a 40 wt% loading the MnO particles were also visible on the surface. Comparison of the electrospun separators showed improved performance relative to a commercial Celgard separator (200 F g-1 vs 141 F g-1).

  12. Properties of PET/PLA Electrospun Blends

    Science.gov (United States)

    Li, Kevin; Cebe, Peggy

    2012-02-01

    Electrospun membranes were fabricated from poly(ethylene terephthalate), PET, co-spun with poly(lactic acid), PLA. The PLA contained 2% of the D-isomer, which served to limit the overall degree of crystallinity. Membranes were deposited from blended solutions of PET/PLA in hexafluoroisopropanol. The PET/PLA composition ranged from 0/100, 75/25, 50/50, 25/75, and 100/0. Electrospun membranes were made using either a static flat plate or a rotating wheel as the counter electrode, yielding unoriented mats or highly oriented tapes, respectively. We report on our investigation of the crystallinity, crystal perfection, and mechanical properties of these materials using differential scanning calorimetry, wide and small angle X-ray scattering, and dynamic mechanical analysis. In particular, we study the ability of one blend component (PET) to crystallize in the presence of existing crystals of the second blend component (PLA) which crystallizes first and at a lower temperature than PET.

  13. Electrospun Ceramic Nanofiber Mats Today: Synthesis, Properties, and Applications

    Science.gov (United States)

    Esfahani, Hamid; Ramakrishna, Seeram

    2017-01-01

    Ceramic nanofibers (NFs) have recently been developed for advanced applications due to their unique properties. In this article, we review developments in electrospun ceramic NFs with regard to their fabrication process, properties, and applications. We find that surface activity of electrospun ceramic NFs is improved by post pyrolysis, hydrothermal, and carbothermal processes. Also, when combined with another surface modification methods, electrospun ceramic NFs result in the advancement of properties and widening of the application domains. With the decrease in diameter and length of a fiber, many properties of fibrous materials are modified; characteristics of such ceramic NFs are different from their wide and long (bulk) counterparts. In this article, electrospun ceramic NFs are reviewed with an emphasis on their applications as catalysts, membranes, sensors, biomaterials, fuel cells, batteries, supercapacitors, energy harvesting systems, electric and magnetic parts, conductive wires, and wearable electronic textiles. Furthermore, properties of ceramic nanofibers, which enable the above applications, and techniques to characterize them are briefly outlined. PMID:29077074

  14. Electrospun Ceramic Nanofiber Mats Today: Synthesis, Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Hamid Esfahani

    2017-10-01

    Full Text Available Ceramic nanofibers (NFs have recently been developed for advanced applications due to their unique properties. In this article, we review developments in electrospun ceramic NFs with regard to their fabrication process, properties, and applications. We find that surface activity of electrospun ceramic NFs is improved by post pyrolysis, hydrothermal, and carbothermal processes. Also, when combined with another surface modification methods, electrospun ceramic NFs result in the advancement of properties and widening of the application domains. With the decrease in diameter and length of a fiber, many properties of fibrous materials are modified; characteristics of such ceramic NFs are different from their wide and long (bulk counterparts. In this article, electrospun ceramic NFs are reviewed with an emphasis on their applications as catalysts, membranes, sensors, biomaterials, fuel cells, batteries, supercapacitors, energy harvesting systems, electric and magnetic parts, conductive wires, and wearable electronic textiles. Furthermore, properties of ceramic nanofibers, which enable the above applications, and techniques to characterize them are briefly outlined.

  15. 3D freeform printing of silk fibroin.

    Science.gov (United States)

    Rodriguez, Maria J; Dixon, Thomas A; Cohen, Eliad; Huang, Wenwen; Omenetto, Fiorenzo G; Kaplan, David L

    2018-04-15

    Freeform fabrication has emerged as a key direction in printing biologically-relevant materials and structures. With this emerging technology, complex structures with microscale resolution can be created in arbitrary geometries and without the limitations found in traditional bottom-up or top-down additive manufacturing methods. Recent advances in freeform printing have used the physical properties of microparticle-based granular gels as a medium for the submerged extrusion of bioinks. However, most of these techniques require post-processing or crosslinking for the removal of the printed structures (Miller et al., 2015; Jin et al., 2016) [1,2]. In this communication, we introduce a novel method for the one-step gelation of silk fibroin within a suspension of synthetic nanoclay (Laponite) and polyethylene glycol (PEG). Silk fibroin has been used as a biopolymer for bioprinting in several contexts, but chemical or enzymatic additives or bulking agents are needed to stabilize 3D structures. Our method requires no post-processing of printed structures and allows for in situ physical crosslinking of pure aqueous silk fibroin into arbitrary geometries produced through freeform 3D printing. 3D bioprinting has emerged as a technology that can produce biologically relevant structures in defined geometries with microscale resolution. Techniques for fabrication of free-standing structures by printing into granular gel media has been demonstrated previously, however, these methods require crosslinking agents and post-processing steps on printed structures. Our method utilizes one-step gelation of silk fibroin within a suspension of synthetic nanoclay (Laponite), with no need for additional crosslinking compounds or post processing of the material. This new method allows for in situ physical crosslinking of pure aqueous silk fibroin into defined geometries produced through freeform 3D printing. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights

  16. Cytocompatibility of a silk fibroin tubular scaffold

    International Nuclear Information System (INIS)

    Wang, Jiannan; Wei, Yali; Yi, Honggen; Liu, Zhiwu; Sun, Dan; Zhao, Huanrong

    2014-01-01

    Regenerated silk fibroin (SF) materials are increasingly used for tissue engineering applications. In order to explore the feasibility of a novel biomimetic silk fibroin tubular scaffold (SFTS) crosslinked by poly(ethylene glycol) diglycidyl ether (PEG-DE), biocompatibility with cells was evaluated. The novel biomimetic design of the SFTS consisted of three distinct layers: a regenerated SF intima, a silk braided media and a regenerated SF adventitia. The SFTS exhibited even silk fibroin penetration throughout the braid, forming a porous layered tube with superior mechanical, permeable and cell adhesion properties that are beneficial to vascular regeneration. Cytotoxicity and cell compatibility were tested on L929 cells and human umbilical vein endothelial cells (EA.hy926). DNA content analysis, scanning electron and confocal microscopies and MTT assay showed no inhibitory effects on DNA replication. Cell morphology, viability and proliferation were good for L929 cells, and satisfactory for EA.hy926 cells. Furthermore, the suture retention strength of the SFTS was about 23 N and the Young's modulus was 0.2–0.3 MPa. Collectively, these data demonstrate that PEG-DE crosslinked SFTS possesses the appropriate cytocompatibility and mechanical properties for use as vascular scaffolds as an alternative to vascular autografts. - Highlights: • A PEG-DE cross-linked small caliber porous silk fibroin tubular scaffold (SFTS) • PEG-DE cross-linked SF film had no inhibitory effect on DNA replication of cells. • Cells cultured on the SFTS showed good morphology, cell viability and proliferative activity. • SFTS would be beneficial to endothelialization. • SFTS had good suture retention strength and flexibility

  17. Electrodeposited silk coatings for functionalized implant applications

    Science.gov (United States)

    Elia, Roberto

    The mechanical and morphological properties of titanium as well as its biocompatibility and osteoinductive characteristics have made it the material of choice for dental implant systems. Although the success rate of titanium implants exceeds 90% in healthy individuals, a large subset of the population has one or more risk factors that inhibit implant integration. Treatments and coatings have been developed to improve clinical outcomes via introduction of appropriate surface topography, texture and roughness or incorporation of bioactive molecules. It is essential that the coatings and associated deposition techniques are controllable and reproducible. Currently, methods of depositing functional coatings are dictated by numerous parameters (temperature, particle size distribution, pH and voltage), which result in variable coating thickness, strength, porosity and weight, and hinder or preclude biomolecule incorporation. Silk is a highly versatile protein with a unique combination of mechanical and physical properties, including tunable degradation, biocompatibility, drug stabilizing capabilities and mechanical properties. Most recently an electrogelation technique was developed which allows for the deposition of gels which dry seamlessly over the contoured topography of the conductive substrate. In this work we examine the potential use of silk electrogels as mechanically robust implant coatings capable of sequestering and releasing therapeutic agents. Electrodeposition of silk electrogels formed in uniform electric fields was characterized with respect to field intensity and deposition time. Gel formation kinetics were used to derive functions which allowed for the prediction of coating deposition over a range of process and solution parameters. Silk electrogel growth orientation was shown to be influenced by the applied electric field. Coatings were reproducible and tunable via intrinsic silk solution properties and extrinsic process parameters. Adhesion was

  18. Silk fibroin based biomimetic artificial extracellular matrix for hepatic tissue engineering applications

    International Nuclear Information System (INIS)

    Kasoju, Naresh; Bora, Utpal

    2012-01-01

    Hepatic tissue engineering, which aims to construct artificial liver tissues, requires a suitable extracellular matrix (ECM) for growth and proliferation of metabolically active hepatocytes. The current paper describes the development of a biomimetic artificial ECM, for hepatic tissue engineering applications, by mimicking the architectural features and biochemical composition of native ECM. Electrospinning was chosen as the fabrication technique of choice, while regenerated silk fibroin (RSF) and galactosylated chitosan (GalCS) were chosen as materials of choice. Poly(ethylene oxide) was used as a processing aid. Methodical optimization studies were performed to obtain smooth and continuous nanofibers with homogenous size distribution. Extensive characterization studies were performed to determine its morphological, physical, chemical/structural, thermal and cytotoxicity properties. Subsequently, detailed in vitro hepatocyte compatibility studies were performed using HepG2 cell line. Remarkably, the studies revealed that the growth, viability, metabolic activity and proliferation of hepatocytes were relatively superior on RSF–GalCS scaffold than on pure RSF and pure GalCS. In summary, the electrospun nanofibrous RSF–GalCS scaffold tries to mimic both architectural and biochemical features of native ECM, and hence could be an appropriate scaffold for in vitro engineering of hepatic tissue. However, additional experiments are needed to confirm the superiority in characteristic functionality of hepatocytes growing on RSF–GalCS scaffold in relation to RSF and GalCS scaffolds, and to test its behavior in vivo. (paper)

  19. Fabrication and Intermolecular Interactions of Silk Fibroin/Hydroxybutyl Chitosan Blended Nanofibers

    Directory of Open Access Journals (Sweden)

    Xiu-Mei Mo

    2011-03-01

    Full Text Available The native extracellular matrix (ECM is composed of a cross-linked porous network of multifibril collagens and glycosaminoglycans. Nanofibrous scaffolds of silk fibroin (SF and hydroxybutyl chitosan (HBC blends were fabricated using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP and trifluoroacetic acid (TFA as solvents to biomimic the native ECM via electrospinning. Scanning electronic microscope (SEM showed that relatively uniform nanofibers could be obtained when 12% SF was blended with 6% HBC at the weight ratio of 50:50. Meanwhile, the average nanofibrous diameter increased when the content of HBC in SF/HBC blends was raised from 20% to 100%. Fourier transform infrared spectra (FTIR and 13C nuclear magnetic resonance (NMR showed SF and HBC molecules existed in hydrogen bonding interactions but HBC did not induce conformation of SF transforming from random coil form to β-sheet structure. X-ray diffraction (XRD confirmed the different structure of SF/HBC blended nanofibers from both SF and HBC. Thermogravimetry-Differential thermogravimetry (TG-DTG results demonstrated that the thermal stability of SF/HBC blend nanofibrous scaffolds was improved. The results indicated that the rearrangement of HBC and SF molecular chain formed a new structure due to stronger hydrogen bonding between SF and HBC. These electrospun SF/HBC blended nanofibers may provide an ideal tissue engineering scaffold and wound dressing.

  20. Spider Silk Processing for Spidroin Recovery from Crossopriza Lyoni Web

    Science.gov (United States)

    Mohtar, J. A.; Ooi, W. L.; Yusuf, F.

    2018-03-01

    Spider silk is a potential biomaterial that can be used in various applications for its outstanding physicomechanical properties attributed by the spidroin composition. Efforts for commercializing spider silks have been mainly focused on the characterization of spidroins from the Entelegyne spiders for exceptional fibre construction. Hence, studies on silk proteins from the Haplogyne species remain neglected. The aim of this study is to isolate spidroin from Crossopriza lyoni web. Silk processing involved the pretreatment of fibres for the shell layer removal from the surface. A screening study was conducted to analyze the effect of temperature, incubation time and agitation speed on spidroin extraction using Ajisawa’s reagent by OFAT analysis followed by statistical optimization of the extraction process via RSM for maximal protein recovery. All parameters exerted significant effect on spidroin recovery (pspider silk to meet the demand for a variety of silk-based products in the near future.

  1. Thin Film Assembly of Spider Silk-like Block Copolymers

    Science.gov (United States)

    2011-01-01

    Shipley, N. H.; Lewis, R. V. Int. J. Biol.Macromol. 1999, 24, 271. (c) Thiel, B. L.; Guess, K. B.; Viney, C. Biopolymers 1997, 41, 703. (13) Silk ...Film Assembly of Spider Silk -like Block Copolymers Sreevidhya T. Krishnaji,†,‡ Wenwen Huang,§ Olena Rabotyagova,†,‡ Eugenia Kharlampieva, ) Ikjun Choi...Received November 26, 2010 We report the self-assembly of monolayers of spider silk -like block copolymers. Langmuir isotherms were obtained for a series of

  2. The effects of corn silk on glycaemic metabolism

    OpenAIRE

    Han Linna; Liu Tongjun; Guo Jianyou; Liu Yongmei

    2009-01-01

    Abstract Background Corn silk contains proteins, vitamins, carbohydrates, Ca, K, Mg and Na salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids. Base on folk remedies, corn silk has been used as an oral antidiabetic agent in China for decades. However, the hypoglycemic activity of it has not yet been understood in terms of modern pharmacological concepts. The purpose of this study is to investigate the effects of corn silk ...

  3. Ptychographic X-ray Tomography of Silk Fiber Hydration

    DEFF Research Database (Denmark)

    Esmaeili, Morteza; Fløystad, Jostein B.; Diaz, Ana

    2013-01-01

    Studying noninvasively the internal nanoporous structure of a single Tussah silk fiber under different humidity conditions, we demonstrate for the first time the feasibility of in-situ ptychographic tomography. The resulting 3D images of the silk fiber interior, obtained at both dry and humid con...... normal to the fiber axis. Exploiting quantitative information on the fiber’s electron density, hydration was found to proceed through interaction with the silk protein rather than filling of pores....

  4. Mechanism of Stabilization of Labile Compounds by Silk Fibroin Proteins

    Science.gov (United States)

    2017-04-05

    saliva, or urine , and their collection and storage is critical to obtain reliable results. Without proper temperature regulation protein biomarkers in... samples for long-term ambient storage and subsequent on-demand recovery and laboratory analysis. Air dried silks provide a protective barrier that...silk in the stabilization of a range of different analytes, including entrapment, storage and recovery. Here, we successfully used silk fibroin as a

  5. SilkDB: a knowledgebase for silkworm biology and genomics

    DEFF Research Database (Denmark)

    Wang, Jing; Xia, Qingyou; He, Ximiao

    2005-01-01

    The Silkworm Knowledgebase (SilkDB) is a web-based repository for the curation, integration and study of silkworm genetic and genomic data. With the recent accomplishment of a approximately 6X draft genome sequence of the domestic silkworm (Bombyx mori), SilkDB provides an integrated representati....... SilkDB is publicly accessible at http://silkworm.genomics.org.cn. Udgivelsesdato: 2005-Jan-1...

  6. Diazonium Chemistry for the Bio-Functionalization of Glassy Nanostring Resonator Arrays

    Directory of Open Access Journals (Sweden)

    Wei Zheng

    2015-07-01

    Full Text Available Resonant glassy nanostrings have been employed for the detection of biomolecules. These devices offer high sensitivity and amenability to large array integration and multiplexed assays. Such a concept has however been impaired by the lack of stable and biocompatible linker chemistries. Diazonium salt reduction-induced aryl grafting is an aqueous-based process providing strong chemical adhesion. In this work, diazonium-based linker chemistry was performed for the first time on glassy nanostrings, which enabled the bio-functionalization of such devices. Large arrays of nanostrings with ultra-narrow widths down to 10 nm were fabricated employing electron beam lithography. Diazonium modification was first developed on SiCN surfaces and validated by X-ray photoelectron spectroscopy. Similarly modified nanostrings were then covalently functionalized with anti-rabbit IgG as a molecular probe. Specific enumeration of rabbit IgG was successfully performed through observation of downshifts of resonant frequencies. The specificity of this enumeration was confirmed through proper negative control experiments. Helium ion microscopy further verified the successful functionalization of nanostrings.

  7. Diazonium Chemistry for the Bio-Functionalization of Glassy Nanostring Resonator Arrays.

    Science.gov (United States)

    Zheng, Wei; Du, Rongbing; Cao, Yong; Mohammad, Mohammad A; Dew, Steven K; McDermott, Mark T; Evoy, Stephane

    2015-07-30

    Resonant glassy nanostrings have been employed for the detection of biomolecules. These devices offer high sensitivity and amenability to large array integration and multiplexed assays. Such a concept has however been impaired by the lack of stable and biocompatible linker chemistries. Diazonium salt reduction-induced aryl grafting is an aqueous-based process providing strong chemical adhesion. In this work, diazonium-based linker chemistry was performed for the first time on glassy nanostrings, which enabled the bio-functionalization of such devices. Large arrays of nanostrings with ultra-narrow widths down to 10 nm were fabricated employing electron beam lithography. Diazonium modification was first developed on SiCN surfaces and validated by X-ray photoelectron spectroscopy. Similarly modified nanostrings were then covalently functionalized with anti-rabbit IgG as a molecular probe. Specific enumeration of rabbit IgG was successfully performed through observation of downshifts of resonant frequencies. The specificity of this enumeration was confirmed through proper negative control experiments. Helium ion microscopy further verified the successful functionalization of nanostrings.

  8. Bio-functionalized MWCNT/hyperbranched polyurethane bionanocomposite for bone regeneration

    International Nuclear Information System (INIS)

    Das, Beauty; Karak, Niranjan; Chattopadhyay, Pronobesh; Upadhyay, Aadesh; Maji, Somnath; Maity, Tapas Kumar; Purkayastha, Manashi Das; Mohanta, Charu lata

    2015-01-01

    The proper fabrication of biomaterials, particularly for purposes like bone regeneration, is of the utmost importance for the clinical success of materials that fulfill the design criteria at bio-interfacial milieu. Building on this aspect, a polyurethane nanocomposite (PNC) was fabricated by the combination of rapeseed protein functionalized multi-walled carbon nanotubes (MWCNTs) and vegetable-oil-based hyperbranched polyurethane. Biofunctionalized MWCNTs showed incredible biocompatibility compared to pristine MWCNTs as ascertained via in vitro and in vivo studies. PNC showed enhanced MG63 cell differentiation ability compared to the control and carboxyl functionalized MWCNT-based nanocomposite, as postulated by alkaline phosphatase activity together with better cellular adhesion, spreading and proliferation. Consequently, a critical-sized fracture gap (6 mm) bridged by the sticky PNC scaffold illustrated rapid bone neoformation within 30–45 d, with 90–93% of the defect area filling up. Histopathological studies demonstrated the reorganization of the normal tibial architecture and biodegradation of the implant. The subsequent toxicological study through cytokine expression, biochemical analysis and hematological studies suggested non-immunogenic and non-toxic effects of PNCs and their degraded/leached products. Their excellent bio-physiological features with high load-bearing ability (49–55.5 Mpa), ductility (675–790%) and biodegradability promote them as the best alternative biomaterials for bone regeneration in a comprehensive manner. (paper)

  9. Template-mediated synthesis and bio-functionalization of flexible lignin-based nanotubes and nanowires

    Science.gov (United States)

    Caicedo, Hector M.; Dempere, Luisa A.; Vermerris, Wilfred

    2012-03-01

    Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15 nm or nanowires with a nominal diameter of 200 nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells.

  10. Template-mediated synthesis and bio-functionalization of flexible lignin-based nanotubes and nanowires

    International Nuclear Information System (INIS)

    Caicedo, Hector M; Vermerris, Wilfred; Dempere, Luisa A

    2012-01-01

    Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15 nm or nanowires with a nominal diameter of 200 nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells. (paper)

  11. Metal nanoparticles triggered persistent negative photoconductivity in silk protein hydrogels

    Science.gov (United States)

    Gogurla, Narendar; Sinha, Arun K.; Naskar, Deboki; Kundu, Subhas C.; Ray, Samit K.

    2016-03-01

    Silk protein is a natural biopolymer with intriguing properties, which are attractive for next generation bio-integrated electronic and photonic devices. Here, we demonstrate the negative photoconductive response of Bombyx mori silk protein fibroin hydrogels, triggered by Au nanoparticles. The room temperature electrical conductivity of Au-silk hydrogels is found to be enhanced with the incorporation of Au nanoparticles over the control sample, due to the increased charge transporting networks within the hydrogel. Au-silk lateral photoconductor devices show a unique negative photoconductive response under an illumination of 325 nm, with excitation energy higher than the characteristic metal plasmon resonance band. The enhanced photoconductance yield in the hydrogels over the silk protein is attributed to the photo-oxidation of amino groups in the β-pleated sheets of the silk around the Au nanoparticles followed by the breaking of charge transport networks. The Au-silk nanocomposite does not show any photoresponse under visible illumination because of the localization of excited charges in Au nanoparticles. The negative photoconductive response of hybrid Au-silk under UV illumination may pave the way towards the utilization of silk for future bio-photonic devices using metal nanoparticle platforms.

  12. Structure-function-property-design interplay in biopolymers: spider silk.

    Science.gov (United States)

    Tokareva, Olena; Jacobsen, Matthew; Buehler, Markus; Wong, Joyce; Kaplan, David L

    2014-04-01

    Spider silks have been a focus of research for almost two decades due to their outstanding mechanical and biophysical properties. Recent advances in genetic engineering have led to the synthesis of recombinant spider silks, thus helping to unravel a fundamental understanding of structure-function-property relationships. The relationships between molecular composition, secondary structures and mechanical properties found in different types of spider silks are described, along with a discussion of artificial spinning of these proteins and their bioapplications, including the role of silks in biomineralization and fabrication of biomaterials with controlled properties. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. Spider Silk as Guiding Biomaterial for Human Model Neurons

    Directory of Open Access Journals (Sweden)

    Frank Roloff

    2014-01-01

    Full Text Available Over the last years, a number of therapeutic strategies have emerged to promote axonal regeneration. An attractive strategy is the implantation of biodegradable and nonimmunogenic artificial scaffolds into injured peripheral nerves. In previous studies, transplantation of decellularized veins filled with spider silk for bridging critical size nerve defects resulted in axonal regeneration and remyelination by invading endogenous Schwann cells. Detailed interaction of elongating neurons and the spider silk as guidance material is unknown. To visualize direct cellular interactions between spider silk and neurons in vitro, we developed an in vitro crossed silk fiber array. Here, we describe in detail for the first time that human (NT2 model neurons attach to silk scaffolds. Extending neurites can bridge gaps between single silk fibers and elongate afterwards on the neighboring fiber. Culturing human neurons on the silk arrays led to an increasing migration and adhesion of neuronal cell bodies to the spider silk fibers. Within three to four weeks, clustered somata and extending neurites formed ganglion-like cell structures. Microscopic imaging of human neurons on the crossed fiber arrays in vitro will allow for a more efficient development of methods to maximize cell adhesion and neurite growth on spider silk prior to transplantation studies.

  14. Silk elasticity as a potential constraint on spider body size.

    Science.gov (United States)

    Rodríguez-Gironés, Miguel A; Corcobado, Guadalupe; Moya-Laraño, Jordi

    2010-10-07

    Silk is known for its strength and extensibility and has played a key role in the radiation of spiders. Individual spiders use different glands to produce silk types with unique sets of proteins. Most research has studied the properties of major ampullate and capture spiral silks and their ecological implications, while little is known about minor ampullate silk, the type used by those spider species studied to date for bridging displacements. A biomechanical model parameterised with available data shows that the minimum radius of silk filaments required for efficient bridging grows with the square root of the spider's body mass, faster than the radius of minor ampullate silk filaments actually produced by spiders. Because the morphology of spiders adapted to walking along or under silk threads is ill suited for moving on a solid surface, for these species there is a negative relationship between body mass and displacement ability. As it stands, the model suggests that spiders that use silk for their displacements are prevented from attaining a large body size if they must track their resources in space. In particular, silk elasticity would favour sexual size dimorphism because males that must use bridging lines to search for females cannot grow large. 2010 Elsevier Ltd. All rights reserved.

  15. Second-order nonlinear optical microscopy of spider silk

    Science.gov (United States)

    Zhao, Yue; Hien, Khuat Thi Thu; Mizutani, Goro; Rutt, Harvey N.

    2017-06-01

    Asymmetric β-sheet protein structures in spider silk should induce nonlinear optical interaction such as second harmonic generation (SHG) which is experimentally observed for a radial line and dragline spider silk using an imaging femtosecond laser SHG microscope. By comparing different spider silks, we found that the SHG signal correlates with the existence of the protein β-sheets. Measurements of the polarization dependence of SHG from the dragline indicated that the β-sheet has a nonlinear response depending on the direction of the incident electric field. We propose a model of what orientation the β-sheet takes in spider silk.

  16. Electrospun nanofibrous SF/P(LLA-CL) membrane: a potential substratum for endothelial keratoplasty.

    Science.gov (United States)

    Chen, Junzhao; Yan, Chenxi; Zhu, Mengyu; Yao, Qinke; Shao, Chunyi; Lu, Wenjuan; Wang, Jing; Mo, Xiumei; Gu, Ping; Fu, Yao; Fan, Xianqun

    2015-01-01

    Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF) has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-ε-caprolactone) (P(LLA-CL)) has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL) can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty. Five scaffolds containing different SF:P(LLA-CL) blended ratios (100:0, 75:25, 50:50, 25:75, 0:100) were manufactured. A human corneal endothelial (B4G12) cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test), cell proliferation (Ki-67, BrdU staining), and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction. Different blended ratios of scaffolds had different light transmittance properties. The 25:75 blended ratio membrane had the best transmittance among these scaffolds. All electrospun nanofibrous membranes showed improved speed of cell adherence when compared with the control group, especially when the P(LLA-CL) ratio increased. The 25:75 blended ratio membranes also had the highest cell proliferation. B4G12 cells could form a monolayer on all scaffolds, and most functional genes were also stably expressed on all scaffolds. Only two genes

  17. Electrospun Nanofibers: New Concepts, Materials, and Applications.

    Science.gov (United States)

    Xue, Jiajia; Xie, Jingwei; Liu, Wenying; Xia, Younan

    2017-08-15

    Electrospinning is a simple and versatile technique that relies on the electrostatic repulsion between surface charges to continuously draw nanofibers from a viscoelastic fluid. It has been applied to successfully produce nanofibers, with diameters down to tens of nanometers, from a rich variety of materials, including polymers, ceramics, small molecules, and their combinations. In addition to solid nanofibers with a smooth surface, electrospinning has also been adapted to generate nanofibers with a number of secondary structures, including those characterized by a porous, hollow, or core-sheath structure. The surface and/or interior of such nanofibers can be further functionalized with molecular species or nanoparticles during or after an electrospinning process. In addition, electrospun nanofibers can be assembled into ordered arrays or hierarchical structures by manipulation of their alignment, stacking, and/or folding. All of these attributes make electrospun nanofibers well-suited for a broad spectrum of applications, including those related to air filtration, water purification, heterogeneous catalysis, environmental protection, smart textiles, surface coating, energy harvesting/conversion/storage, encapsulation of bioactive species, drug delivery, tissue engineering, and regenerative medicine. Over the past 15 years, our group has extensively explored the use of electrospun nanofibers for a range of applications. Here we mainly focus on two examples: (i) use of ceramic nanofibers as catalytic supports for noble-metal nanoparticles and (ii) exploration of polymeric nanofibers as scaffolding materials for tissue regeneration. Because of their high porosity, high surface area to volume ratio, well-controlled composition, and good thermal stability, nonwoven membranes made of ceramic nanofibers are terrific supports for catalysts based on noble-metal nanoparticles. We have investigated the use of ceramic nanofibers made of various oxides, including SiO 2 , TiO 2

  18. Thermal conductivity of electrospun polyethylene nanofibers.

    Science.gov (United States)

    Ma, Jian; Zhang, Qian; Mayo, Anthony; Ni, Zhonghua; Yi, Hong; Chen, Yunfei; Mu, Richard; Bellan, Leon M; Li, Deyu

    2015-10-28

    We report on the structure-thermal transport property relation of individual polyethylene nanofibers fabricated by electrospinning with different deposition parameters. Measurement results show that the nanofiber thermal conductivity depends on the electric field used in the electrospinning process, with a general trend of higher thermal conductivity for fibers prepared with stronger electric field. Nanofibers produced at a 45 kV electrospinning voltage and a 150 mm needle-collector distance could have a thermal conductivity of up to 9.3 W m(-1) K(-1), over 20 times higher than the typical bulk value. Micro-Raman characterization suggests that the enhanced thermal conductivity is due to the highly oriented polymer chains and enhanced crystallinity in the electrospun nanofibers.

  19. Plasma etching of electrospun polymeric nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Verdonck, Patrick [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil)]. E-mail: verdonck@imec.be; Braga Caliope, Priscila [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); Moral Hernandez, Emilio del [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); Silva, Ana Neilde R. da [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); FATEC-SP, Pca Fernando Prestes, 30 Sao Paulo, SP (Brazil)

    2006-10-25

    Electrospun polymeric nanofibres have several applications because of their high surface area to volume and high length to diameter ratios. This paper investigates the influence of plasma etching on these fibres and the etching mechanisms. For the characterization, SEM analysis was performed to determine the forms and shapes of the fibres and SEM photos were analysed by the technique of mathematical morphology, in order to determine the area on the sample occupied by the fibres and the frequency distribution of the nanofibre diameters. The results showed that the oxygen plasma etches the nanofibres much faster when ion bombardment is present. The form of the fibres is not altered by the etching, indicating the possibility of transport of oxygen atoms over the fibre surface. The most frequent diameter, somewhat surprisingly, is not significantly dependent on the etching process, and remains of the order of 80 nm, indicating that fibres with smaller diameters are etched at high rates.

  20. Characterization of electrospun lignin based carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri [School of Engineering, Thornbrough Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada); Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada)

    2015-05-22

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 – 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  1. Characterization of electrospun lignin based carbon fibers

    International Nuclear Information System (INIS)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-01-01

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 – 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems

  2. Silk constructs for delivery of muskuloskeletal therapeutics

    Science.gov (United States)

    Meinel, Lorenz; Kaplan, David L.

    2012-01-01

    Silk fibroin (SF) is a biopolymer with distinguishing features from many other bio- as well as synthetic polymers. From a biomechanical and drug delivery perspective, SF combines remarkable versatility for scaffolding (solid implants, hydrogels, threads, solutions), with advanced mechanical properties and good stabilization and controlled delivery of entrapped protein and small molecule drugs, respectively. It is this combination of mechanical and pharmaceutical features which render SF so exciting for biomedical applications. his pattern along with the versatility of this biopolymer have been translated into progress for musculoskeletal applications. We review the use and potential of silk fibroin for systemic and localized delivery of therapeutics in diseases affecting the musculoskeletal system. We also present future directions for this biopolymer as well as the necessary research and development steps for their achievement. PMID:22522139

  3. Silk fibroin nanostructured materials for biomedical applications

    Science.gov (United States)

    Mitropoulos, Alexander N.

    Nanostructured biopolymers have proven to be promising to develop novel biomedical applications where forming structures at the nanoscale normally occurs by self-assembly. However, synthesizing these structures can also occur by inducing materials to transition into other forms by adding chemical cross-linkers, changing pH, or changing ionic composition. Understanding the generation of nanostructures in fluid environments, such as liquid organic solvents or supercritical fluids, has not been thoroughly examined, particularly those that are based on protein-based block-copolymers. Here, we examine the transformation of reconstituted silk fibroin, which has emerged as a promising biopolymer due to its biocompatibility, biodegradability, and ease of functionalization, into submicron spheres and gel networks which offer applications in tissue engineering and advanced sensors. Two types of gel networks, hydrogels and aerogels, have small pores and large surface areas that are defined by their structure. We design and analyze silk nanoparticle formation using a microfluidic device while offering an application for drug delivery. Additionally, we provide a model and characterize hydrogel formation from micelles to nanoparticles, while investigating cellular response to the hydrogel in an in vitro cell culture model. Lastly, we provide a second model of nanofiber formation during near-critical and supercritical drying and characterize the silk fibroin properties at different drying pressures which, when acting as a stabilizing matrix, shows to improve the activity of entrapped enzymes dried at different pressures. This work has created new nanostructured silk fibroin forms to benefit biomedical applications that could be applied to other fibrous proteins.

  4. Gaochang Buddhism and the Silk Road

    Directory of Open Access Journals (Sweden)

    Wang Xin

    2014-02-01

    Full Text Available At the crossroads between the West and the East in ancient times, one point along the Silk Road was Gaochang (the Turpan basin in Xinjiang which played an important role in cultural exchange and the spread of Buddhism. The bidirectional influence of Buddhism in Gaochang was achieved as Buddhism spread eastward, and through its westward transmission which resulted in Gaochang’s unique and significant position in the history of cultural interaction.

  5. The effects of corn silk on glycaemic metabolism.

    Science.gov (United States)

    Guo, Jianyou; Liu, Tongjun; Han, Linna; Liu, Yongmei

    2009-11-23

    Corn silk contains proteins, vitamins, carbohydrates, Ca, K, Mg and Na salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids. Base on folk remedies, corn silk has been used as an oral antidiabetic agent in China for decades. However, the hypoglycemic activity of it has not yet been understood in terms of modern pharmacological concepts. The purpose of this study is to investigate the effects of corn silk on glycaemic metabolism. Alloxan and adrenalin induced hyperglycemic mice were used in the study. The effects of corn silk on blood glucose, glycohemoglobin (HbA1c), insulin secretion, damaged pancreatic beta-cells, hepatic glycogen and gluconeogenesis in hyperglycemic mice were studied respectively. After the mice were orally administered with corn silk extract, the blood glucose and the HbA1c were significantly decreased in alloxan-induced hyperglycemic mice (p corn silk extract 15 days later. Also, the body weight of the alloxan-induced hyperglycemic mice was increased gradually. However, ascension of blood glucose induced by adrenalin and gluconeogenesis induced by L-alanine were not inhibited by corn silk extract treatment (p > 0.05). Although corn silk extract increased the level of hepatic glycogen in the alloxan-induced hyperglycemic mice, there was no significant difference between them and that of the control group(p > 0.05). Corn silk extract markedly reduced hyperglycemia in alloxan-induced diabetic mice. The action of corn silk extract on glycaemic metabolism is not via increasing glycogen and inhibiting gluconeogenesis but through increasing insulin level as well as recovering the injured beta-cells. The results suggest that corn silk extract may be used as a hypoglycemic food or medicine for hyperglycemic people in terms of this modern pharmacological study.

  6. Early events in the evolution of spider silk genes.

    Directory of Open Access Journals (Sweden)

    James Starrett

    Full Text Available Silk spinning is essential to spider ecology and has had a key role in the expansive diversification of spiders. Silk is composed primarily of proteins called spidroins, which are encoded by a multi-gene family. Spidroins have been studied extensively in the derived clade, Orbiculariae (orb-weavers, from the suborder Araneomorphae ('true spiders'. Orbicularians produce a suite of different silks, and underlying this repertoire is a history of duplication and spidroin gene divergence. A second class of silk proteins, Egg Case Proteins (ECPs, is known only from the orbicularian species, Lactrodectus hesperus (Western black widow. In L. hesperus, ECPs bond with tubuliform spidroins to form egg case silk fibers. Because most of the phylogenetic diversity of spiders has not been sampled for their silk genes, there is limited understanding of spidroin gene family history and the prevalence of ECPs. Silk genes have not been reported from the suborder Mesothelae (segmented spiders, which diverged from all other spiders >380 million years ago, and sampling from Mygalomorphae (tarantulas, trapdoor spiders and basal araneomorph lineages is sparse. In comparison to orbicularians, mesotheles and mygalomorphs have a simpler silk biology and thus are hypothesized to have less diversity of silk genes. Here, we present cDNAs synthesized from the silk glands of six mygalomorph species, a mesothele, and a non-orbicularian araneomorph, and uncover a surprisingly rich silk gene diversity. In particular, we find ECP homologs in the mesothele, suggesting that ECPs were present in the common ancestor of extant spiders, and originally were not specialized to complex with tubuliform spidroins. Furthermore, gene-tree/species-tree reconciliation analysis reveals that numerous spidroin gene duplications occurred after the split between Mesothelae and Opisthothelae (Mygalomorphae plus Araneomorphae. We use the spidroin gene tree to reconstruct the evolution of amino acid

  7. Recombinant protein blends: silk beyond natural design.

    Science.gov (United States)

    Dinjaski, Nina; Kaplan, David L

    2016-06-01

    Recombinant DNA technology and new material concepts are shaping future directions in biomaterial science for the design and production of the next-generation biomaterial platforms. Aside from conventionally used synthetic polymers, numerous natural biopolymers (e.g., silk, elastin, collagen, gelatin, alginate, cellulose, keratin, chitin, polyhydroxyalkanoates) have been investigated for properties and manipulation via bioengineering. Genetic engineering provides a path to increase structural and functional complexity of these biopolymers, and thereby expand the catalog of available biomaterials beyond that which exists in nature. In addition, the integration of experimental approaches with computational modeling to analyze sequence-structure-function relationships is starting to have an impact in the field by establishing predictive frameworks for determining material properties. Herein, we review advances in recombinant DNA-mediated protein production and functionalization approaches, with a focus on hybrids or combinations of proteins; recombinant protein blends or 'recombinamers'. We highlight the potential biomedical applications of fibrous protein recombinamers, such as Silk-Elastin Like Polypeptides (SELPs) and Silk-Bacterial Collagens (SBCs). We also discuss the possibility for the rationale design of fibrous proteins to build smart, stimuli-responsive biomaterials for diverse applications. We underline current limitations with production systems for these proteins and discuss the main trends in systems/synthetic biology that may improve recombinant fibrous protein design and production. Copyright © 2016. Published by Elsevier Ltd.

  8. Electrospun nanofibrous SF/P(LLA-CL membrane: a potential substratum for endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Chen JZ

    2015-05-01

    Full Text Available Junzhao Chen,1,* Chenxi Yan,1,* Mengyu Zhu,1,* Qinke Yao,1 Chunyi Shao,1 Wenjuan Lu,1 Jing Wang,2 Xiumei Mo,2 Ping Gu,1 Yao Fu,1 Xianqun Fan1 1Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 2Biomaterials and Tissue Engineering Laboratory, College of Chemistry and Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-Ɛ-caprolactone (P(LLA-CL has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty.Methods: Five scaffolds containing different SF:P(LLA-CL blended ratios (100:0, 75:25, 50:50, 25:75, 0:100 were manufactured. A human corneal endothelial (B4G12 cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test, cell proliferation (Ki-67, BrdU staining, and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction.Results: Different blended ratios of scaffolds

  9. Electrospun nanofibres in agriculture and the food industry: a review.

    Science.gov (United States)

    Noruzi, Masumeh

    2016-11-01

    The interesting characteristics of electrospun nanofibres, such as high surface-to-volume ratio, nanoporosity, and high safety, make them suitable candidates for use in a variety of applications. In the recent decade, electrospun nanofibres have been applied to different potential fields such as filtration, wound dressing, drug delivery, etc. and a significant number of review papers have been published in these fields. However, the use of electrospun nanofibres in agriculture is comparatively novel and is still in its infancy. In this paper, the specific applications of electrospun nanofibres in agriculture and food science, including plant protection using pheromone-loaded nanofibres, plant protection using encapsulation of biocontrol agents, preparation of protective clothes for farm workers, encapsulation of agrochemical materials, deoxyribonucleic acid extraction in agricultural research studies, pre-concentration and measurement of pesticides in crops and environmental samples, preparation of nanobiosensors for pesticide detection, encapsulation of food materials, fabrication of food packaging materials, and filtration of beverage products are reviewed and discussed. This paper may help researchers develop the use of electrospun nanofibres in agriculture and food science to address some serious problems such as the intensive use of pesticides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  10. Electrospun nanofibre fibrinogen for urinary tract tissue reconstruction

    International Nuclear Information System (INIS)

    McManus, Michael; Boland, Eugene; Sell, Scott; Bowen, Whitney; Koo, Harry; Simpson, David; Bowlin, Gary

    2007-01-01

    The purpose of this study was to demonstrate that human bladder smooth muscle cells (HBSM) remodel electrospun fibrinogen mats. Fibrinogen scaffolds were electrospun and disinfected using standard methods. Scaffolds were seeded with 5 x 10 4 HBSM per scaffold. Cultures were supplemented with aprotinin concentrations of 0 KIU ml -1 (no aprotinin), 100 KIU ml -1 or 1000 KIU ml -1 and incubated with twice weekly media changes. Samples were removed for evaluation at 1, 3, 7 and 14 days. Cultured scaffolds were evaluated with a WST-1 cell proliferation assay, scanning electron microscopy and histology. Cell culture demonstrated that HBSM readily migrated into and initiated remodelling of the electrospun fibrinogen scaffolds by deposition of collagen. Proliferation was suppressed during this initial phase with respect to a 2D control due to cell migration. Histology confirmed that proliferation increased during the later stages of remodelling. Remodelling was slower at higher aprotinin concentrations. These results demonstrate that HBSM rapidly remodel an electrospun fibrinogen scaffold and deposit native collagen. The process can be modulated using aprotinin, a protease inhibitor. These initial findings indicate that there is tremendous potential for electrospun fibrinogen as a urologic tissue engineering scaffold with the ultimate goal of producing an implantable acellular product that would promote cellular in-growth and in situ tissue regeneration

  11. Production of fine powder from silk by radiation

    International Nuclear Information System (INIS)

    Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu

    2000-01-01

    Silk fine power was prepared directly from silk fiber irradiated with an accelerated electron beam(EB). Irradiated silk fiber was well pulverized only by physical crushing using ball mill without any chemical pretreatment. Raw and degummed silk fibers were irradiated at ambient temperature in the dose range of 250-1000 kGy. Although unirradiated silk fibers were not pulverized at all, irradiated fibers were easily pulverized and showed higher conversion from fiber to powder for higher doses. The presence of oxygen in the irradiation atmosphere enhanced pulverization of silk fiber. Raw silk fibers were less pulverized compared to degummed ones. The electron microscope observation showed that the minimum particle size of silk powder obtained from fiber irradiated by 1000 kGy in oxygen was less than 10 microns. It was found that fibroin powder obtained in this work dissolved remarkably into cold water, thought unirradiated fibroin fiber had little solubility even in hot water. A typical soluble fraction was about 60% for fibroin powder obtained from fiber irradiated by 1000 kGy in oxygen. (author)

  12. Acute and Subacute Toxicity Evaluation of Corn Silk Extract.

    Science.gov (United States)

    Ha, Ae Wha; Kang, Hyeon Jung; Kim, Sun Lim; Kim, Myung Hwan; Kim, Woo Kyoung

    2018-03-01

    Many studies have reported therapeutic efficacy of corn silk extract. However, research on its toxicity and safe dose range is limited. Thus, the objective of this study was to determine the acute and subacute toxicity of corn silk extract in ICR mice. To determine acute toxicity, corn silk extract containing high levels of maysin was orally administered to mice at a dose of 0 or 2,000 mg/kg. Clinical symptoms, mortality, and body weight changes were recorded for 14 days. To determine subacute toxicity, corn silk extract was orally administered to mice over a 4-week period, and then body weight, water and food consumption, and organ weight were determined. In addition, urine and serum analyses were performed. In the acute toxicity study, no death or abnormal symptoms was observed in all treatment groups during the study period. Body weights did not show any significant change compared to those of the control group. Lethal dose of corn silk extract was estimated to be more than 2,000 mg/kg. In the 4-week subacute toxicity study, there was no corn silk extract related toxic effect on body weight, water intake, food consumption, urine parameters, clinical chemistry, or organ weight. Histopathological examination showed no abnormality related to the administration of corn silk extract at 500 mg/kg. The maximum non-toxic dose of corn silk extract containing high levels of maysin was found to be more than 500 mg/kg.

  13. Clay-Enriched Silk Biomaterials for Bone Formation

    Science.gov (United States)

    Mieszawska, Aneta J.; Llamas, Jabier Gallego; Vaiana, Christopher A.; Kadakia, Madhavi P.; Naik, Rajesh R.; Kaplan, David L.

    2011-01-01

    The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone specific uses. Clay montmorillonite (Cloisite ® Na+) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared to silk films doped with sodium silicate as controls for support of human bone marrow derived mesenchymal stem cells (hMSCs) in osteogenic culture. The cells adhered and proliferated on the silk/clay composites over two weeks. Quantitative real-time RT-PCR analysis revealed increased transcript levels for alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col I) osteogenic markers in the cells cultured on the silk/clay films in comparison to the controls. Early evidence for bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that the silk/clay composite systems may be useful for further study toward bone regenerative needs. PMID:21549864

  14. Re-opening the silk road to transform Chinese trade

    NARCIS (Netherlands)

    N. Mao (Ning); M.J. McAleer (Michael)

    2017-01-01

    textabstractUnder anti-globalization and isolationism, China is seeking to portray itself as a new leader for globalization under the banner of the Silk Road initiative. Meanwhile, China's traditional and comparatively advantaged industry, silk, has faced dire predicaments and challenges for long

  15. The failure mode of natural silk epoxy triggered composite tubes

    International Nuclear Information System (INIS)

    Eshkour, R A; Ariffin, A K; Zulkifli, R; Sulong, A B; Azhari, C H

    2012-01-01

    In this study the quasi static compression test over natural silk epoxy triggered composite tubes has been carried out, the natural silk epoxy composite tubes consist of 24 layer of woven natural silk as reinforcement and thermoset epoxy resin as matrix which both of them i e natural silk and epoxy have excellent mechanical properties More over the natural silk have better moisture resistance in comparison with other natural reinforcements, the length of tubes are 50, 80 and 120 mm The natural silk epoxy composite tubes are associated with an external trigger which includes 4 steel pieces welded on downside flat plate fixture The hand lay up fabrication method has been used to make the natural silk epoxy composite tubes Instron universal testing machine with 250 KN load capacity has been employed to accomplish this investigation The failure modes of natural silk epoxy triggered composite tubes has been investigated by representative photographs which has been taken by a high resolution camera(12 2 Mp) during the quasi static compression test, from the photographs is observed the failure modes is progressive local buckling

  16. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th ...

  17. Re-Opening the Silk Road to Transform Chinese Trade

    NARCIS (Netherlands)

    M. Ning (Mao); M.J. McAleer (Michael)

    2017-01-01

    textabstractUnder anti-globalization and isolationism, China is seeking to portray itself as a new leader for globalization under the banner of the Silk Road initiative. Meanwhile, China’s traditional and comparatively advantaged industry, silk, has faced dire predicaments and challenges for long

  18. Structure, composition and mechanical properties of the silk fibres of ...

    Indian Academy of Sciences (India)

    The silk egg case and orb web of spiders are elaborate structures that are assembled from a number of components. We analysed the structure, the amino acid and fibre compositions, and the tensile properties of the silk fibres of the egg case of Nephila clavata. SEM shows that the outer and inner covers of the egg case ...

  19. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands .... be used in the silk-manufacture industry. This paper analyses .... (figure 3C); and are highly birefringent (figure 3D).

  20. Production of fine powder from silk by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Ishida, Kazunari; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan)

    2000-03-01

    Silk fine power was prepared directly from silk fiber irradiated with an accelerated electron beam(EB). Irradiated silk fiber was well pulverized only by physical crushing using ball mill without any chemical pretreatment. Raw and degummed silk fibers were irradiated at ambient temperature in the dose range of 250-1000 kGy. Although unirradiated silk fibers were not pulverized at all, irradiated fibers were easily pulverized and showed higher conversion from fiber to powder for higher doses. The presence of oxygen in the irradiation atmosphere enhanced pulverization of silk fiber. Raw silk fibers were less pulverized compared to degummed ones. The electron microscope observation showed that the minimum particle size of silk powder obtained from fiber irradiated by 1000 kGy in oxygen was less than 10 microns. It was found that fibroin powder obtained in this work dissolved remarkably into cold water, thought unirradiated fibroin fiber had little solubility even in hot water. A typical soluble fraction was about 60% for fibroin powder obtained from fiber irradiated by 1000 kGy in oxygen. (author)

  1. Surface biofunctionalization of β-TCP blocks using aptamer 74 for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Ardjomandi, N.; Huth, J. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Stamov, D.R. [JPK Instruments AG, Berlin (Germany); Henrich, A. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Klein, C. [Dental Practice Zahngesundheit Waiblingen, Waiblingen (Germany); Wendel, H.-P. [Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, Tübingen (Germany); Reinert, S. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Alexander, D., E-mail: dorothea.alexander@med.uni-tuebingen.de [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany)

    2016-10-01

    Successful bone regeneration following oral and maxillofacial surgeries depends on efficient functionalization strategies that allow the recruitment of osteogenic progenitor cells at the tissue/implant interface. We have previously identified aptamer 74, which exhibited a binding affinity for osteogenically induced jaw periosteal cells (JPCs). In the present study, this aptamer was used for the surface biofunctionalization of β-tricalcium phosphate (β-TCP) blocks. Atomic force microscopy (AFM) measurements showed increased binding activity of aptamer 74 towards osteogenically induced JPCs compared to untreated controls. The immobilization efficiency of aptamer 74 was analyzed using the QuantiFluor ssDNA assay for 2D surfaces and by amino acid analysis for 3D β-TCP constructs. Following the successful immobilization of aptamer 74 in 2D culture wells and on 3D constructs, in vitro assays showed no significant differences in cell proliferation compared to unmodified surfaces. Interestingly, JPC mineralization was significantly higher on the 2D surfaces and higher cell adhesion was detected on the 3D constructs with immobilized aptamer. Herein, we report an established, biocompatible β-TCP matrix with surface immobilization of aptamer 74, which enhances properties such as cell adhesion on 3D constructs and mineralization on 2D surfaces. Further studies need to be performed to improve the immobilization efficiency and to develop a suitable approach for JPC mineralization growing within 3D β-TCP constructs. - Highlights: • Covalent binding of aptamer 74 on PLGA-coated β-tricalcium phosphate constructs. • AFM analysis of rupture forces between aptamer 74 and jaw periosteal cells. • Analysis of jaw periosteal cell functions on aptamer coated β-TCP constructs.

  2. Biofunctionalization of aqueous dispersed, alumina membrane-templated polymer nanorods for use in enzymatic chemiluminescence assays.

    Science.gov (United States)

    Mark, Sonny S; Stolper, Samuel I; Baratti, Carla; Park, Jason Y; Kricka, Larry J

    2008-09-01

    The noncovalent immobilization of alkaline phosphatase (ALP) onto aqueous dispersed nylon 6 nanorods ( approximately 310 nm mean diameter; approximately 6 microm mean length) prepared by anodic aluminum oxide (AAO) membrane templating was studied. Using multi-stacked layer-by-layer (LBL) assembly with the cationic quaternary ammonium polymer Sapphire II , the amount of ALP enzyme loaded onto the polymer nanostructures was found to be 115+/-7 microg mg(-1) nanorod. The biofunctionalized nanorods were also characterized for their chemiluminescent activity with the dioxetane substrate, CSPD . The results indicate that the kinetic parameters, K(m) and V(max), for the catalytic activity of the nanostructure-bound ALP enzyme are different from those of soluble ('free') ALP. While the K(m) value was measured to be 156 microM for free ALP, the apparent K(m) value determined for the LBL-immobilized ALP is approximately 20% lower (122 microM). Furthermore, despite the relatively high enzyme loading capacity of the nanorods, the specific activity of the bound ALP enzyme was found to be almost nine times lower than that measured for free ALP. Finally, additional experiments revealed that the catalytic activities of both free ALP and nanorod-conjugated ALP are affected similarly by changes in pH, with optimal performance levels occurring under conditions of pH 9.5. To the best of our knowledge, this study represents the first report examining the preparation of aqueous dispersed, AAO-templated polymer nanorods for potential application as enzyme scaffolds in chemiluminescent-based assay systems.

  3. Surface biofunctionalization of β-TCP blocks using aptamer 74 for bone tissue engineering

    International Nuclear Information System (INIS)

    Ardjomandi, N.; Huth, J.; Stamov, D.R.; Henrich, A.; Klein, C.; Wendel, H.-P.; Reinert, S.; Alexander, D.

    2016-01-01

    Successful bone regeneration following oral and maxillofacial surgeries depends on efficient functionalization strategies that allow the recruitment of osteogenic progenitor cells at the tissue/implant interface. We have previously identified aptamer 74, which exhibited a binding affinity for osteogenically induced jaw periosteal cells (JPCs). In the present study, this aptamer was used for the surface biofunctionalization of β-tricalcium phosphate (β-TCP) blocks. Atomic force microscopy (AFM) measurements showed increased binding activity of aptamer 74 towards osteogenically induced JPCs compared to untreated controls. The immobilization efficiency of aptamer 74 was analyzed using the QuantiFluor ssDNA assay for 2D surfaces and by amino acid analysis for 3D β-TCP constructs. Following the successful immobilization of aptamer 74 in 2D culture wells and on 3D constructs, in vitro assays showed no significant differences in cell proliferation compared to unmodified surfaces. Interestingly, JPC mineralization was significantly higher on the 2D surfaces and higher cell adhesion was detected on the 3D constructs with immobilized aptamer. Herein, we report an established, biocompatible β-TCP matrix with surface immobilization of aptamer 74, which enhances properties such as cell adhesion on 3D constructs and mineralization on 2D surfaces. Further studies need to be performed to improve the immobilization efficiency and to develop a suitable approach for JPC mineralization growing within 3D β-TCP constructs. - Highlights: • Covalent binding of aptamer 74 on PLGA-coated β-tricalcium phosphate constructs. • AFM analysis of rupture forces between aptamer 74 and jaw periosteal cells. • Analysis of jaw periosteal cell functions on aptamer coated β-TCP constructs.

  4. Self-assembly of silk fibroin under osmotic stress

    Science.gov (United States)

    Sohn, Sungkyun

    The supramolecular self-assembly behavior of silk fibroin was investigated using osmotic stress technique. In Chapter 2, a ternary phase diagram of water-silk-LiBr was constructed based on X-ray results on the osmotically stressed regenerated silk fibroin of Bombyx mori silkworm. Microscopic data indicated that silk I is a hydrated structure and a rough estimate of the number of water molecules lost by the structure upon converting from silk I to silk II has been made, and found to be about 2.2 per [GAGAGS] hexapeptide. In Chapter 3, wet-spinning of osmotically stressed, regenerated silk fibroin was performed, based on the prediction that the enhanced control over structure and phase behavior using osmotic stress method helps improve the physical properties of wet-spun regenerated silk fibroin fibers. The osmotic stress was applied in order to pre-structure the regenerated silk fibroin molecule from its original random coil state to more oriented state, manipulating the phase of the silk solution in the phase diagram before the start of spinning. Monofilament fiber with a diameter of 20 microm was produced. In Chapter 4, we investigated if there is a noticeable synergistic osmotic pressure increase between co-existing polymeric osmolyte and salt when extremely highly concentrated salt molecules are present both at sample subphase and stressing subphase, as is the case of silk fibroin self-assembly. The equilibration method that measures osmotic pressure relative to a reference with known osmotic pressure was introduced. Osmotic pressure of aqueous LiBr solution up to 2.75M was measured and it was found that the synergistic effect was insignificant up to this salt concentration. Solution parameters of stressing solutions and Arrhenius kinetics based on time-temperature relationship for the equilibration process were derived as well. In Chapter 5, self-assembly behavior of natural silk fibroin within the gland of Bombyx mori silkworm was investigated using osmotic

  5. Corn silk induces nitric oxide synthase in murine macrophages.

    Science.gov (United States)

    Kim, Kyung A; Choi, Sang Kyu; Choi, Hye Seon

    2004-12-31

    Corn silk has been purified as an anticoagulant previously and the active component is a polysaccharide with a molecular mass of 135 kDa. It activates murine macrophages to induce nitric oxide synthase (NOS) and generate substantial amounts of NO in time and dose-dependent manners. It was detectable first at 15 h after stimulation by corn silk, peaked at 24 h, and undetectable by 48 h. Induction of NOS is inhibited by pyrolidine dithiocarbamate (PDTC) and genistein, an inhibitor of nuclear factor kappa B (NF-kappaB) and tyrosine kinase, respectively, indicating that iNOS stimulated by corn silk is associated with tyrosine kinase and NF-kappaB signaling pathways. IkappaB-alpha degradation was detectible at 10 min, and the level was restored at 120 min after treatment of corn silk. Corn silk induced nuclear translocation of NF-kappaB by phosphorylation and degradation of IkappaB-alpha.

  6. Study on silk yellowing induced by gamma-irradiation

    International Nuclear Information System (INIS)

    Tsukada, Masuhiro; Aoki, Akira

    1985-01-01

    The changes in the yellow color of silk threads with total dose of irradiation applied were described and studied by a colorimetric method and by monochrome photography. The change into a yellow color of the specimen in the course of irradiation was clearly detected in photographs using filters, 2B and SC 56 under light conditions at the wavelength of 366 nm. The b/L value measured by colorimetry in undegummed and degummed silk fibers sharply increased in the early stage of irradiation. Yellow color indices (b/L) of the specimen subjected to gamma-irradiation continued to increase and the yellow color of the silk threads became more pronounced above a total dose of irradiation of 21 Mrad. The b/L value of the undegummed silk fiber which had deen irradiated was about 2 times that of the degummed silk fiber. (author)

  7. Optical surface profiling of orb-web spider capture silks

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D M; Joyce, A M; Staib, G R [Department of Physics, Macquarie University, Sydney, NSW 2109 (Australia); Herberstein, M E, E-mail: deb.kane@mq.edu.a [Department of Biological Sciences, Macquarie University, Sydney, NSW 2109 (Australia)

    2010-09-15

    Much spider silk research to date has focused on its mechanical properties. However, the webs of many orb-web spiders have evolved for over 136 million years to evade visual detection by insect prey. It is therefore a photonic device in addition to being a mechanical device. Herein we use optical surface profiling of capture silks from the webs of adult female St Andrews cross spiders (Argiope keyserlingi) to successfully measure the geometry of adhesive silk droplets and to show a bowing in the aqueous layer on the spider capture silk between adhesive droplets. Optical surface profiling shows geometric features of the capture silk that have not been previously measured and contributes to understanding the links between the physical form and biological function. The research also demonstrates non-standard use of an optical surface profiler to measure the maximum width of a transparent micro-sized droplet (microlens).

  8. Optical surface profiling of orb-web spider capture silks

    International Nuclear Information System (INIS)

    Kane, D M; Joyce, A M; Staib, G R; Herberstein, M E

    2010-01-01

    Much spider silk research to date has focused on its mechanical properties. However, the webs of many orb-web spiders have evolved for over 136 million years to evade visual detection by insect prey. It is therefore a photonic device in addition to being a mechanical device. Herein we use optical surface profiling of capture silks from the webs of adult female St Andrews cross spiders (Argiope keyserlingi) to successfully measure the geometry of adhesive silk droplets and to show a bowing in the aqueous layer on the spider capture silk between adhesive droplets. Optical surface profiling shows geometric features of the capture silk that have not been previously measured and contributes to understanding the links between the physical form and biological function. The research also demonstrates non-standard use of an optical surface profiler to measure the maximum width of a transparent micro-sized droplet (microlens).

  9. Effects of alkyl polyglycoside (APG) on Bombyx mori silk degumming and the mechanical properties of silk fibroin fibre

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fei; Zhang, Yu-Qing, E-mail: sericult@suda.edu.cn

    2017-05-01

    Alkyl polyglycoside (APG), a nonionic surfactant, is often considered to be a green surfactant and is synthesized using glucose and long chain fatty alcohols. It is used as a degumming agent of Bombyx mori silk fibre in this study for the first time. We studied APG systematically in comparison to the traditional degumming methods, such as aqueous solutions of sodium carbonate (Na{sub 2}CO{sub 3}) and neutral soap (NS). After repeatedly boiling silk fibres in an aqueous solution of 0.25% APG three times for 30 min and using a bath ratio of 1:90–120 (g/mL), sericin was completely removed from the fibre. SDS-PAGE showed that the degumming in APG did not induce an evident breakage of the silk fibroin peptide chains, including the light chain and P25 protein. The tensile properties, thermal analysis, and scanning electron microscopic (SEM) observation of the degummed fibroin fibre all show that APG is a degumming agent similar to NS and far superior to Na{sub 2}CO{sub 3}. These results indicate that APG is an environment-friendly silk degumming/refining agent in the silk textile industry and in the manufacture of silk floss quilts. - Graphical abstract: APG has potential uses as a green degumming/refining reagent for silkworm cocoons or silk fibres in the silk industry and for sericulture production. Display Omitted.

  10. Multiscale mechanisms of nutritionally induced property variation in spider silks

    Science.gov (United States)

    Nobbs, Madeleine; Martens, Penny J.; Tso, I-Min; Chuang, Wei-Tsung; Chang, Chung-Kai; Sheu, Hwo-Shuenn

    2018-01-01

    Variability in spider major ampullate (MA) silk properties at different scales has proven difficult to determine and remains an obstacle to the development of synthetic fibers mimicking MA silk performance. A multitude of techniques may be used to measure multiscale aspects of silk properties. Here we fed five species of Araneoid spider solutions that either contained protein or were protein deprived and performed silk tensile tests, small and wide-angle X-ray scattering (SAXS/WAXS), amino acid composition analyses, and silk gene expression analyses, to resolve persistent questions about how nutrient deprivation induces variations in MA silk mechanical properties across scales. Our analyses found that the properties of each spider’s silk varied differently in response to variations in their protein intake. We found changes in the crystalline and non-crystalline nanostructures to play specific roles in inducing the property variations we found. Across treatment MaSp expression patterns differed in each of the five species. We found that in most species MaSp expression and amino acid composition variations did not conform with our predictions based on a traditional MaSp expression model. In general, changes to the silk’s alanine and proline compositions influenced the alignment of the proteins within the silk’s amorphous region, which influenced silk extensibility and toughness. Variations in structural alignment in the crystalline and non-crystalline regions influenced ultimate strength independent of genetic expression. Our study provides the deepest insights thus far into the mechanisms of how MA silk properties vary from gene expression to nanostructure formations to fiber mechanics. Such knowledge is imperative for promoting the production of synthetic silk fibers. PMID:29390013

  11. Bio-functionalizing of α-MnO_2 nanorods with natural L-amino acids: A favorable adsorbent for the removal of Cd(II) ions

    International Nuclear Information System (INIS)

    Mallakpour, Shadpour; Motirasoul, Forough

    2017-01-01

    α-MnO_2 nanorods were prepared by hydrothermal method and then the surface of these nanorods were covalently biofunctionalized with natural L-amino acids (alanine, phenylalanine, leucine, isoleucine, methionine, and valine). The modified α-MnO_2 nanorods were analyzed by Fourier transform infrared spectroscopy and X-ray diffraction. Morphological studies were carried out by field emission scanning electron microscopy and transmission electron microscopy. The morphology of nanorods was improved after biofunctionalization and aggregation was reduced. In addition, the thermal gravimetric analysis was used for demonstrating a successful grafting of amino acids to the surface of α-MnO_2 nanorods and determine the degree of functionalization. The amount of amino acids grafted onto α-MnO_2 surface was estimated to be 5–32 wt%. Finally, the α-MnO_2 and α-MnO_2-L-valine were investigated as adsorbents for the removal of cadmium ions from aqueous solution. The results showed that they have a potential to be used as effective adsorbents for cadmium ions removal from the aqueous solution. The equilibrium adsorption data showed the best fit for the pseudo-second-order and the Freundlich models. - Highlights: • α-MnO_2 nanorods were biofunctionalized with natural L-amino acids. • Biofunctionalized α-MnO_2 nanorods by solvothermal strategy were fully characterized. • Cadmium adsorption property of α-MnO_2 and α-MnO_2-L-valine was studied.

  12. Fabrication of electrospun nanofibrous membranes for membrane distillation application

    KAUST Repository

    Francis, Lijo

    2013-02-01

    Nanofibrous membranes of Matrimid have been successfully fabricated using an electrospinning technique under optimized conditions. Nanofibrous membranes are found to be highly hydrophobic with a high water contact angle of 130°. Field emission scanning electron microscopy and pore size distribution analysis revealed the big pore size structure of electrospun membranes to be greater than 2 μm and the pore size distribution is found to be narrow. Flat sheet Matrimid membranes were fabricated via casting followed by phase inversion. The morphology, pore size distribution, and water contact angle were measured and compared with the electrospun membranes. Both membranes fabricated by electrospinning and phase inversion techniques were tested in a direct contact membrane distillation process. Electrospun membranes showed high water vapor flux of 56 kg/m2-h, which is very high compared to the casted membrane as well as most of the fabricated and commercially available highly hydrophobic membranes. ©2013 Desalination Publications.

  13. Angiogenic potential of human macrophages on electrospun bioresorbable vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Garg, K; Sell, S A; Madurantakam, P; Bowlin, G L, E-mail: glbowlin@vcu.ed [Virginia Commonwealth University, Richmond, VA 23284 (United States)

    2009-06-15

    The aim of this study was to investigate macrophage interactions with electrospun scaffolds and quantify the expression of key angiogenic growth factors in vitro. This study will further help in evaluating the potential of these electrospun constructs as vascular grafts for tissue repair and regeneration in situ. Human peripheral blood macrophages were seeded in serum free media on electrospun (10 mm) discs of polydioxanone (PDO), elastin and PDO:elastin blends (50:50, 70:30 and 90:10). The growth factor secretion was analyzed by ELISA. Macrophages produced high levels of vascular endothelial growth factor and acidic fibroblast growth factor. Transforming growth factor beta-1 (TGF-beta1) secretion was relatively low and there was negligible production of basic fibroblast growth factor. Therefore, it can be anticipated that these scaffolds will support tissue regeneration and angiogenesis. (communication)

  14. A review on electrospun nanofibers for oral drug delivery

    Directory of Open Access Journals (Sweden)

    Abbas Akhgari

    2017-10-01

    Full Text Available Nowadays, polymer nanofibers have gained attention due to remarkable characteristics such as high porosity and large surface area to volume ratio. Among their fabrication methods, electrospinning technique has been attracted as a simple and reproducible approach. It is a versatile, simple and cost-effective technique for the production of continuous nanofibers with acceptable characteristics such as high porosity, high surface area to volume ratio, high loading capacity and encapsulation efficiency, delivery of multiple drugs, and enhancement of drug solubility. Due to these properties electrospun nanofibers have been extensively used for different biomedical applications including wound dressing, tissue engineering, enzyme immobilization, artificial organs, and drug delivery. Different synthetic and natural polymers have been successfully electrospun into ultrafine fibers. Using electrospun nanofibers as vehicles for oral drug delivery has been investigated in different release manners- fast, biphasic or sustained release. This article presents a review on application of electrospinning technique in oral drug delivery.

  15. The mechanical properties of dry, electrospun fibrinogen fibers

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Stephen; Sigley, Justin; Helms, Christine C. [Department of Physics, Wake Forest University, Winston-Salem, NC 27109 (United States); Stitzel, Joel [Department of Biomedical Engineering, Wake Forest University Health Sciences, Winston-Salem, NC, 27157 (United States); Berry, Joel; Bonin, Keith [Department of Physics, Wake Forest University, Winston-Salem, NC 27109 (United States); Guthold, Martin, E-mail: gutholdm@wfu.edu [Department of Physics, Wake Forest University, Winston-Salem, NC 27109 (United States)

    2012-02-01

    Due to their low immunogenicity, biodegradability and native cell-binding domains, fibrinogen fibers may be good candidates for tissue engineering scaffolds, drug delivery vehicles and other medical devices. We used a combined atomic force microscope (AFM)/optical microscope technique to study the mechanical properties of individual, electrospun fibrinogen fibers in dry, ambient conditions. The AFM was used to stretch individual fibers suspended over 13.5 {mu}m wide grooves in a transparent substrate. The optical microscope, located below the sample, was used to monitor the stretching process. Electrospun fibrinogen fibers (diameter, 30-200 nm) can stretch to 74% beyond their original length before rupturing at a stress of 2.1 GPa. They can stretch elastically up to 15% beyond their original length. Using incremental stress-strain curves the viscoelastic behavior of these fibers was determined. The total stretch modulus was 4.2 GPa while the relaxed elastic modulus was 3.7 GPa. When held at constant strain, fibrinogen fibers display stress relaxation with a fast and slow relaxation time of 1.2 s and 11 s. In comparison to native and electrospun collagen fibers, dry electrospun fibrinogen fibers are significantly more extensible and elastic. In comparison to wet electrospun fibrinogen fibers, dry fibers are about 1000 times stiffer. - Highlights: Black-Right-Pointing-Pointer Fabricated dry, electrospun, fibrinogen fibers; average diameter, D{sub avg.} = 95 nm. Black-Right-Pointing-Pointer Determined mechanical properties with combined atomic force/optical microscope. Black-Right-Pointing-Pointer Fibers are very extensible ({epsilon}{sub max} = 74%) and elastic ({epsilon}{sub elastic} = 15%). Black-Right-Pointing-Pointer Fiber total modulus, E{sub tot.} = 4.2 GPa; elastic modulus, E{sub el.} = 3.7 GPa. Black-Right-Pointing-Pointer Fiber stress relaxation times: {tau}{sub 1} = 1.2 s and {tau}{sub 2} = 11 s.

  16. The mechanical properties of dry, electrospun fibrinogen fibers

    International Nuclear Information System (INIS)

    Baker, Stephen; Sigley, Justin; Helms, Christine C.; Stitzel, Joel; Berry, Joel; Bonin, Keith; Guthold, Martin

    2012-01-01

    Due to their low immunogenicity, biodegradability and native cell-binding domains, fibrinogen fibers may be good candidates for tissue engineering scaffolds, drug delivery vehicles and other medical devices. We used a combined atomic force microscope (AFM)/optical microscope technique to study the mechanical properties of individual, electrospun fibrinogen fibers in dry, ambient conditions. The AFM was used to stretch individual fibers suspended over 13.5 μm wide grooves in a transparent substrate. The optical microscope, located below the sample, was used to monitor the stretching process. Electrospun fibrinogen fibers (diameter, 30–200 nm) can stretch to 74% beyond their original length before rupturing at a stress of 2.1 GPa. They can stretch elastically up to 15% beyond their original length. Using incremental stress–strain curves the viscoelastic behavior of these fibers was determined. The total stretch modulus was 4.2 GPa while the relaxed elastic modulus was 3.7 GPa. When held at constant strain, fibrinogen fibers display stress relaxation with a fast and slow relaxation time of 1.2 s and 11 s. In comparison to native and electrospun collagen fibers, dry electrospun fibrinogen fibers are significantly more extensible and elastic. In comparison to wet electrospun fibrinogen fibers, dry fibers are about 1000 times stiffer. - Highlights: ► Fabricated dry, electrospun, fibrinogen fibers; average diameter, D avg. = 95 nm. ► Determined mechanical properties with combined atomic force/optical microscope. ► Fibers are very extensible (ε max = 74%) and elastic (ε elastic = 15%). ► Fiber total modulus, E tot. = 4.2 GPa; elastic modulus, E el. = 3.7 GPa. ► Fiber stress relaxation times: τ 1 = 1.2 s and τ 2 = 11 s.

  17. The influence of specific binding of collagen-silk chimeras to silk biomaterials on hMSC behavior.

    Science.gov (United States)

    An, Bo; DesRochers, Teresa M; Qin, Guokui; Xia, Xiaoxia; Thiagarajan, Geetha; Brodsky, Barbara; Kaplan, David L

    2013-01-01

    Collagen-like proteins in the bacteria Streptococcus pyogenes adopt a triple-helix structure with a thermal stability similar to that of animal collagens, can be expressed in high yield in Escherichia coli and can be easily modified through molecular biology techniques. However, potential applications for such recombinant collagens are limited by their lack of higher order structure to achieve the physical properties needed for most biomaterials. To overcome this problem, the S. pyogenes collagen domain was fused to a repetitive Bombyx mori silk consensus sequence, as a strategy to direct specific non-covalent binding onto solid silk materials whose superior stability, mechanical and material properties have been previously established. This approach resulted in the successful binding of these new collagen-silk chimeric proteins to silk films and porous scaffolds, and the binding affinity could be controlled by varying the number of repeats in the silk sequence. To explore the potential of collagen-silk chimera for regulating biological activity, integrin (Int) and fibronectin (Fn) binding sequences from mammalian collagens were introduced into the bacterial collagen domain. The attachment of bioactive collagen-silk chimeras to solid silk biomaterials promoted hMSC spreading and proliferation substantially in comparison to the controls. The ability to combine the biomaterial features of silk with the biological activities of collagen allowed more rapid cell interactions with silk-based biomaterials, improved regulation of stem cell growth and differentiation, as well as the formation of artificial extracellular matrices useful for tissue engineering applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Electrospun polyurethane membranes for Tissue Engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Laís P., E-mail: lagabriel@gmail.com [National Institute of Biofabrication, Campinas (Brazil); Department of Chemical Engineering, University of Campinas, Campinas (Brazil); Rodrigues, Ana Amélia [National Institute of Biofabrication, Campinas (Brazil); Department of Medical Sciences, University of Campinas, Campinas (Brazil); Macedo, Milton; Jardini, André L.; Maciel Filho, Rubens [National Institute of Biofabrication, Campinas (Brazil); Department of Chemical Engineering, University of Campinas, Campinas (Brazil)

    2017-03-01

    Tissue Engineering proposes, among other things, tissue regeneration using scaffolds integrated with biological molecules, growth factors or cells for such regeneration. In this research, polyurethane membranes were prepared using the electrospinning technique in order to obtain membranes to be applied in Tissue Engineering, such as epithelial, drug delivery or cardiac applications. The influence of fibers on the structure and morphology of the membranes was studied using scanning electron microscopy (SEM), the structure was evaluated by Fourier transform infrared spectroscopy (FT-IR), and the thermal stability was analyzed by thermogravimetry analysis (TGA). In vitro cells attachment and proliferation was investigated by SEM, and in vitro cell viability was studied by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays and Live/Dead® assays. It was found that the membranes present an homogeneous morphology, high porosity, high surface area/volume ratio, it was also observed a random fiber network. The thermal analysis showed that the membrane degradation started at 254 °C. In vitro evaluation of fibroblasts cells showed that fibroblasts spread over the membrane surface after 24, 48 and 72 h of culture. This study supports the investigation of electrospun polyurethane membranes as biocompatible scaffolds for Tissue Engineering applications and provides some guidelines for improved biomaterials with desired properties.

  19. Electrospun biodegradable polymers loaded with bactericide agents

    Directory of Open Access Journals (Sweden)

    Ramaz Katsarava

    2016-03-01

    Full Text Available Development of materials with an antimicrobial activity is fundamental for different sectors, including medicine and health care, water and air treatment, and food packaging. Electrospinning is a versatile and economic technique that allows the incorporation of different natural, industrial, and clinical agents into a wide variety of polymers and blends in the form of micro/nanofibers. Furthermore, the technique is versatile since different constructs (e.g. those derived from single electrospinning, co-electrospinning, coaxial electrospinning, and miniemulsion electrospinning can be obtained to influence the ability to load agents with different characteristics and stability and to modify the release behaviour. Furthermore, antimicrobial agents can be loaded during the electrospinning process or by a subsequent coating process. In order to the mitigate burst release effect, it is possible to encapsulate the selected drug into inorganic nanotubes and nanoparticles, as well as in organic cyclodextrine polysaccharides. In the same way, processes that involve covalent linkage of bactericide agents during surface treatment of electrospun samples may also be considered. The present review is focused on more recent works concerning the electrospinning of antimicrobial polymers. These include chitosan and common biodegradable polymers with activity caused by the specific load of agents such as metal and metal oxide particles, quaternary ammonium compounds, hydantoin compounds, antibiotics, common organic bactericides, and bacteriophages.

  20. Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber

    International Nuclear Information System (INIS)

    Yang, Jen Ming; Yang, Jhe Hao; Tsou, Shu Chun; Ding, Chian Hua; Hsu, Chih Chin; Yang, Kai Chiang; Yang, Chun Chen; Chen, Ko Shao; Chen, Szi Wen; Wang, Jong Shyan

    2016-01-01

    To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1 day seeded. Cell–cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

  1. Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jen Ming, E-mail: jmyang@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 333, Taiwan, ROC (China); Yang, Jhe Hao [Department of Electronic Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Tsou, Shu Chun; Ding, Chian Hua [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 333, Taiwan, ROC (China); Hsu, Chih Chin [Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan, ROC (China); School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan, ROC (China); Yang, Kai Chiang [School of Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan, ROC (China); Yang, Chun Chen [Department of Chemical Engineering, Ming-Chi University of Science and Technology, New Taipei City, Taiwan, ROC (China); Chen, Ko Shao [Department of Materials Engineering, Tatung University, Taipei, Taiwan, ROC (China); Chen, Szi Wen [Department of Electronic Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Wang, Jong Shyan [Department of Physical Therapy and the Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan, Taiwan, ROC (China)

    2016-09-01

    To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1 day seeded. Cell–cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

  2. Inhibitory effect of corn silk on skin pigmentation.

    Science.gov (United States)

    Choi, Sang Yoon; Lee, Yeonmi; Kim, Sung Soo; Ju, Hyun Min; Baek, Ji Hwoon; Park, Chul-Soo; Lee, Dong-Hyuk

    2014-03-03

    In this study, the inhibitory effect of corn silk on melanin production was evaluated. This study was performed to investigate the inhibitory effect of corn silk on melanin production in Melan-A cells by measuring melanin production and protein expression. The corn silk extract applied on Melan-A cells at a concentration of 100 ppm decreased melanin production by 37.2% without cytotoxicity. This was a better result than arbutin, a positive whitening agent, which exhibited a 26.8% melanin production inhibitory effect at the same concentration. The corn silk extract did not suppress tyrosinase activity but greatly reduced the expression of tyrosinase in Melan-A cells. In addition, corn silk extract was applied to the human face with hyperpigmentation, and skin color was measured to examine the degree of skin pigment reduction. The application of corn silk extract on faces with hyperpigmentation significantly reduced skin pigmentation without abnormal reactions. Based on the results above, corn silk has good prospects for use as a material for suppressing skin pigmentation.

  3. Inhibitory Effect of Corn Silk on Skin Pigmentation

    Directory of Open Access Journals (Sweden)

    Sang Yoon Choi

    2014-03-01

    Full Text Available In this study, the inhibitory effect of corn silk on melanin production was evaluated. This study was performed to investigate the inhibitory effect of corn silk on melanin production in Melan-A cells by measuring melanin production and protein expression. The corn silk extract applied on Melan-A cells at a concentration of 100 ppm decreased melanin production by 37.2% without cytotoxicity. This was a better result than arbutin, a positive whitening agent, which exhibited a 26.8% melanin production inhibitory effect at the same concentration. The corn silk extract did not suppress tyrosinase activity but greatly reduced the expression of tyrosinase in Melan-A cells. In addition, corn silk extract was applied to the human face with hyperpigmentation, and skin color was measured to examine the degree of skin pigment reduction. The application of corn silk extract on faces with hyperpigmentation significantly reduced skin pigmentation without abnormal reactions. Based on the results above, corn silk has good prospects for use as a material for suppressing skin pigmentation.

  4. Effects of silk fibroin in murine dry eye

    Science.gov (United States)

    Kim, Chae Eun; Lee, Ji Hyun; Yeon, Yeung Kyu; Park, Chan Hum; Yang, Jaewook

    2017-03-01

    The study aimed to investigate the effects of silk fibroin in a mouse model of dry eye. The experimental dry eye mouse model was developed using more than twelve-weeks-old NOD.B10.H2b mice exposing them to 30-40% ambient humidity and injecting them with scopolamine hydrobromide for 10 days. Tear production and corneal irregularity score were measured by the instillation of phosphate buffered saline or silk fibroin. Corneal detachment and conjunctival goblet cell density were observed by hematoxylin and eosin or periodic acid Schiff staining in the cornea or conjunctiva. The expression of inflammatory markers was detected by immunohistochemistry in the lacrimal gland. The silk group tear production was increased, and corneal smoothness was improved. The corneal epithelial cells and conjunctival goblet cells were recovered in the silk groups. The expression of inflammatory factors was inhibited in the lacrimal gland of the silk group. These results show that silk fibroin improved the cornea, conjunctiva, and lacrimal gland in the mouse model of dry eye. These findings suggest that silk fibroin has anti-inflammatory effects in the experimental models of dry eye.

  5. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    Energy Technology Data Exchange (ETDEWEB)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

    2010-08-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  6. The processing and heterostructuring of silk with light

    Science.gov (United States)

    Sidhu, Mehra S.; Kumar, Bhupesh; Singh, Kamal P.

    2017-09-01

    Spider silk is a tough, elastic and lightweight biomaterial, although there is a lack of tools available for non-invasive processing of silk structures. Here we show that nonlinear multiphoton interactions of silk with few-cycle femtosecond pulses allow the processing and heterostructuring of the material in ambient air. Two qualitatively different responses, bulging by multiphoton absorption and plasma-assisted ablation, are observed for low- and high-peak intensities, respectively. Plasma ablation allows us to make localized nanocuts, microrods, nanotips and periodic patterns with minimal damage while preserving molecular structure. The bulging regime facilitates confined bending and microwelding of silk with materials such as metal, glass and Kevlar with strengths comparable to pristine silk. Moreover, analysis of Raman bands of microwelded joints reveals that the polypeptide backbone remains intact while perturbing its weak hydrogen bonds. Using this approach, we fabricate silk-based functional topological microstructures, such as Mobiüs strips, chiral helices and silk-based sensors.

  7. The processing and heterostructuring of silk with light.

    Science.gov (United States)

    Sidhu, Mehra S; Kumar, Bhupesh; Singh, Kamal P

    2017-09-01

    Spider silk is a tough, elastic and lightweight biomaterial, although there is a lack of tools available for non-invasive processing of silk structures. Here we show that nonlinear multiphoton interactions of silk with few-cycle femtosecond pulses allow the processing and heterostructuring of the material in ambient air. Two qualitatively different responses, bulging by multiphoton absorption and plasma-assisted ablation, are observed for low- and high-peak intensities, respectively. Plasma ablation allows us to make localized nanocuts, microrods, nanotips and periodic patterns with minimal damage while preserving molecular structure. The bulging regime facilitates confined bending and microwelding of silk with materials such as metal, glass and Kevlar with strengths comparable to pristine silk. Moreover, analysis of Raman bands of microwelded joints reveals that the polypeptide backbone remains intact while perturbing its weak hydrogen bonds. Using this approach, we fabricate silk-based functional topological microstructures, such as Mobiüs strips, chiral helices and silk-based sensors.

  8. Silk-microfluidics for advanced biotechnological applications: A progressive review.

    Science.gov (United States)

    Konwarh, Rocktotpal; Gupta, Prerak; Mandal, Biman B

    2016-01-01

    Silk based biomaterials have not only carved a unique niche in the domain of regenerative medicine but new avenues are also being explored for lab-on-a-chip applications. It is pertinent to note that biospinning of silk represents nature's signature microfluidic-maneuver. Elucidation of non-Newtonian flow of silk in the glands of spiders and silkworms has inspired researchers to fabricate devices for continuous extrusion and concentration of silk. Microfluidic channel networks within porous silk scaffolds ensure optimal nutrient and oxygen supply apart from serving as precursors for vascularization in tissue engineering applications. On the other hand, unique topographical features and surface wettability of natural silk fibers have inspired development of a number of simple and cost-effective devices for applications like blood typing and chemical sensing. This review mirrors the recent progress and challenges in the domain of silk-microfluidics for prospective avant-garde applications in the realm of biotechnology. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Binding Quantum Dots to Silk Biomaterials for Optical Sensing

    Directory of Open Access Journals (Sweden)

    Disi Lu

    2015-01-01

    Full Text Available Quantum dots (QDs, have great potential for fabricating optical sensing devices and imaging biomaterial degradation in vivo. In the present study, 2-mercaptoethylamine- (MEA- and mercaptopropionic acid- (MPA- capped CdTe-QDs were physically incorporated in silk films that contained a high content (>30% of crystalline beta-sheet structure. The beta-sheets were induced by the addition of glycerol, water annealing, glycerol/annealing, or treatment with methanol. Incorporation of QDs did not influence the formation of beta-sheets. When the films were extracted with water, most QDs remained associated with the silk, based on the retention of photoluminescence in the silk films and negligible photoluminescence in the extracts. Compared to the solution state, photoluminescence intensity significantly decreased for MEA-QDs but not for MPA-QDs in the silk films, while the emission maximum blue shifted (≈4 nm slightly for both. Further film digestion using protease XIV, alpha-chymotrypsin, and the combination of the two proteases suggested that QDs may be bound to the silk beta-sheet regions but not the amorphous regions. QDs photoluminescence in silk films was quenched when the concentration of hydrogen peroxide (H2O2 was above 0.2-0.3 mM, indicating the QDs-incorporated silk films can be used to report oxidation potential in solution.

  10. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    International Nuclear Information System (INIS)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A; Hedhammar, My; Johansson, Jan; Blom, Tobias; Leifer, Klaus

    2010-01-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  11. Formation of different gold nanostructures by silk nanofibrils

    International Nuclear Information System (INIS)

    Fang, Guangqiang; Yang, Yuhong; Yao, Jinrong; Shao, Zhengzhong; Chen, Xin

    2016-01-01

    Metal nanostructures that have unique size- and shape-dependent electronic, optical and chemical properties gain more and more attention in modern science and technology. In this article, we show the possibility that we are able to obtain different gold nanostructures simply with the help of silk nanofibrils. We demonstrate that only by varying the pH of the reaction solution, we get gold nanoparticles, nano-icosahedrons, nanocubes, and even microplates. Particularly, we develop a practical method for the preparation of gold microplates in acid condition in the presence of silk nanofibrils, which is impossible by using other forms of silk protein. We attribute the role of silk nanofibrils in the formation of gold nanostructure to their reduction ability from several specific amino acid residues, and the suitable structural anisotropic features to sustain the crystal growth after the reduction process. Although the main purpose of this article is to demonstrate that silk nanofibrils are able to mediate the formation of different gold nanostructure, we show the potential applications of these resulting gold nanostructures, such as surface-enhanced Raman scattering (SERS) and photothermal transformation effect, as same as those produced by other methods. In conclusion, we present in this communication a facile and green synthesis route to prepare various gold nanostructures with silk nanofibrils by simply varying pH in the reaction system, which has remarkable advantages in future biomedical applications. - Highlights: • Different Au nanostructures can be obtained by a facile and green protein reduction method. • Silk nanofibrils serve as both reductant and template in the formation of Au nanostructures. • Different Au nanostructures can be obtained simply by regulating the pH in the medium. • Large Au microplates can be obtained with a cheap, abundant, sustainable silk protein. • Silk/Au hybrid nanocomposites show potential application in SERS and

  12. The effects of corn silk on glycaemic metabolism

    Directory of Open Access Journals (Sweden)

    Han Linna

    2009-11-01

    Full Text Available Abstract Background Corn silk contains proteins, vitamins, carbohydrates, Ca, K, Mg and Na salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids. Base on folk remedies, corn silk has been used as an oral antidiabetic agent in China for decades. However, the hypoglycemic activity of it has not yet been understood in terms of modern pharmacological concepts. The purpose of this study is to investigate the effects of corn silk on glycaemic metabolism. Methods Alloxan and adrenalin induced hyperglycemic mice were used in the study. The effects of corn silk on blood glucose, glycohemoglobin (HbA1c, insulin secretion, damaged pancreatic β-cells, hepatic glycogen and gluconeogenesis in hyperglycemic mice were studied respectively. Results After the mice were orally administered with corn silk extract, the blood glucose and the HbA1c were significantly decreased in alloxan-induced hyperglycemic mice (p 0.05. Although corn silk extract increased the level of hepatic glycogen in the alloxan-induced hyperglycemic mice, there was no significant difference between them and that of the control group(p > 0.05. Conclusion Corn silk extract markedly reduced hyperglycemia in alloxan-induced diabetic mice. The action of corn silk extract on glycaemic metabolism is not via increasing glycogen and inhibiting gluconeogenesis but through increasing insulin level as well as recovering the injured β-cells. The results suggest that corn silk extract may be used as a hypoglycemic food or medicine for hyperglycemic people in terms of this modern pharmacological study.

  13. Formation of different gold nanostructures by silk nanofibrils

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Guangqiang [State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433 (China); Yang, Yuhong [Research Centre for Analysis and Measurement, Fudan University, Shanghai 200433 (China); Yao, Jinrong; Shao, Zhengzhong [State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433 (China); Chen, Xin, E-mail: chenx@fudan.edu.cn [State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433 (China)

    2016-07-01

    Metal nanostructures that have unique size- and shape-dependent electronic, optical and chemical properties gain more and more attention in modern science and technology. In this article, we show the possibility that we are able to obtain different gold nanostructures simply with the help of silk nanofibrils. We demonstrate that only by varying the pH of the reaction solution, we get gold nanoparticles, nano-icosahedrons, nanocubes, and even microplates. Particularly, we develop a practical method for the preparation of gold microplates in acid condition in the presence of silk nanofibrils, which is impossible by using other forms of silk protein. We attribute the role of silk nanofibrils in the formation of gold nanostructure to their reduction ability from several specific amino acid residues, and the suitable structural anisotropic features to sustain the crystal growth after the reduction process. Although the main purpose of this article is to demonstrate that silk nanofibrils are able to mediate the formation of different gold nanostructure, we show the potential applications of these resulting gold nanostructures, such as surface-enhanced Raman scattering (SERS) and photothermal transformation effect, as same as those produced by other methods. In conclusion, we present in this communication a facile and green synthesis route to prepare various gold nanostructures with silk nanofibrils by simply varying pH in the reaction system, which has remarkable advantages in future biomedical applications. - Highlights: • Different Au nanostructures can be obtained by a facile and green protein reduction method. • Silk nanofibrils serve as both reductant and template in the formation of Au nanostructures. • Different Au nanostructures can be obtained simply by regulating the pH in the medium. • Large Au microplates can be obtained with a cheap, abundant, sustainable silk protein. • Silk/Au hybrid nanocomposites show potential application in SERS and

  14. Alternating current impedance spectroscopic analysis of biofunctionalized vertically-aligned silica nanospring surface for biosensor applications

    Science.gov (United States)

    Timalsina, Yukta P.

    In this dissertation, a process of vertically-aligned (silica) nanosprings (VANS) based biosensor development is presented. Alternating current (AC) impedance spectroscopy has been used to analyze sensor response as a function of saline phosphate (SP) buffer and biological solutions. The sensor is a parallel plate capacitor consisting of two glass substrates coated with indium tin oxide (ITO), where the VANS [or randomly-aligned nanosprings (RANS)] grown on one substrate serve as the dielectric spacer layer. The response of a VANS device as a function of ionic concentration in SP buffer was examined and an equivalent circuit model was developed. The results demonstrated that VANS sensors exhibited greater sensitivity to the changes in SP concentration relative to the ITO sensors, which serve as controls. The biofunctionalized VANS surface via physisorption and the cross-linker method demonstrates the repeatability, specificity, and selectivity of the binding. The physisorption of biotinylated immunoglobulin G (B-IgG) onto the VANS surface simplifies the whole sensing procedure for the detection of glucose oxidase, since the avidin-conjugated glucose oxidase (Av-GOx) can directly be immobilized on the B-IgG. The cross linker method involves the covalent attachment of antibodies onto the functionalized VANS surface via imine bond. The experiments revealed that the VANS sensor response is solely the result of the interaction of target molecule i.e. mouse IgG with the probe layer, i.e. goat antimouse IgG (GalphaM IgG). It was determined that VANS-based sensors exhibit a greater magnitude of change between successive bio-layers relative to the controls above 100 Hz, which indicates that the addition of biomolecules inhibits the diffusion of ions and changes the effective dielectric response of the VANS via biomolecular polarization. The study of ionic transport in nanosprings suggested that conductance follows a scaling law. It was demonstrated that a VANS-based device

  15. Inhibitory Effect of Corn Silk on Skin Pigmentation

    OpenAIRE

    Sang Yoon Choi; Yeonmi Lee; Sung Soo Kim; Hyun Min Ju; Ji Hwoon Baek; Chul-Soo Park; Dong-Hyuk Lee

    2014-01-01

    In this study, the inhibitory effect of corn silk on melanin production was evaluated. This study was performed to investigate the inhibitory effect of corn silk on melanin production in Melan-A cells by measuring melanin production and protein expression. The corn silk extract applied on Melan-A cells at a concentration of 100 ppm decreased melanin production by 37.2% without cytotoxicity. This was a better result than arbutin, a positive whitening agent, which exhibited a 26.8% melanin prod...

  16. Spider silk reinforced by graphene or carbon nanotubes

    Science.gov (United States)

    Lepore, Emiliano; Bosia, Federico; Bonaccorso, Francesco; Bruna, Matteo; Taioli, Simone; Garberoglio, Giovanni; Ferrari, Andrea C.; Pugno, Nicola Maria

    2017-09-01

    Spider silk has promising mechanical properties, since it conjugates high strength (~1.5 GPa) and toughness (~150 J g-1). Here, we report the production of silk incorporating graphene and carbon nanotubes by spider spinning, after feeding spiders with the corresponding aqueous dispersions. We observe an increment of the mechanical properties with respect to pristine silk, up to a fracture strength ~5.4 GPa and a toughness modulus ~1570 J g-1. This approach could be extended to other biological systems and lead to a new class of artificially modified biological, or ‘bionic’, materials.

  17. Plasticity in Major Ampullate Silk Production in Relation to Spider Phylogeny and Ecology

    Science.gov (United States)

    Boutry, Cecilia; Řezáč, Milan; Blackledge, Todd Alan

    2011-01-01

    Spider major ampullate silk is a high-performance biomaterial that has received much attention. However, most studies ignore plasticity in silk properties. A better understanding of silk plasticity could clarify the relative importance of chemical composition versus processing of silk dope for silk properties. It could also provide insight into how control of silk properties relates to spider ecology and silk uses. We compared silk plasticity (defined as variation in the properties of silk spun by a spider under different conditions) between three spider clades in relation to their anatomy and silk biochemistry. We found that silk plasticity exists in RTA clade and orbicularian spiders, two clades that differ in their silk biochemistry. Orbiculariae seem less dependent on external spinning conditions. They probably use a valve in their spinning duct to control friction forces and speed during spinning. Our results suggest that plasticity results from different processing of the silk dope in the spinning duct. Orbicularian spiders seem to display better control of silk properties, perhaps in relation to their more complex spinning duct valve. PMID:21818328

  18. Plasticity in major ampullate silk production in relation to spider phylogeny and ecology.

    Directory of Open Access Journals (Sweden)

    Cecilia Boutry

    Full Text Available Spider major ampullate silk is a high-performance biomaterial that has received much attention. However, most studies ignore plasticity in silk properties. A better understanding of silk plasticity could clarify the relative importance of chemical composition versus processing of silk dope for silk properties. It could also provide insight into how control of silk properties relates to spider ecology and silk uses. We compared silk plasticity (defined as variation in the properties of silk spun by a spider under different conditions between three spider clades in relation to their anatomy and silk biochemistry. We found that silk plasticity exists in RTA clade and orbicularian spiders, two clades that differ in their silk biochemistry. Orbiculariae seem less dependent on external spinning conditions. They probably use a valve in their spinning duct to control friction forces and speed during spinning. Our results suggest that plasticity results from different processing of the silk dope in the spinning duct. Orbicularian spiders seem to display better control of silk properties, perhaps in relation to their more complex spinning duct valve.

  19. SU-8 photoresist-derived electrospun carbon nanofibres as high ...

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 40; Issue 3. SU-8 photoresist-derived electrospun carbon nanofibres as high-capacity anode material for lithium ion battery. M KAKUNURI S KAUSHIK A SAINI C S SHARMA. Volume 40 Issue 3 June 2017 pp 435-439 ...

  20. Conductive Au nanowires regulated by silk fibroin nanofibers

    Science.gov (United States)

    Dong, Bo-Ju; Lu, Qiang

    2014-03-01

    Conductive Au-biopolymer composites have promising applications in tissue engineering such as nerve tissue regeneration. In this study, silk fibroin nanofibers were formed in aqueous solution by regulating silk self-assembly process and then used as template for Au nanowire fabrication. We performed the synthesis of Au seeds by repeating the seeding cycles for several times in order to increase the density of Au seeds on the nanofibers. After electroless plating, densely decorated Au seeds grew into irregularly shaped particles following silk nanofiber to fill the gaps between particles and finally form uniform continuous nanowires. The conductive property of the Au-silk fibroin nanowires was studied with current-voltage ( I-V) measurement. A typical ohmic behavior was observed, which highlighted their potential applications in nerve tissue regeneration.

  1. Silk-polypyrrole biocompatible actuator performance under biologically relevant conditions

    Science.gov (United States)

    Hagler, Jo'elen; Peterson, Ben; Murphy, Amanda; Leger, Janelle

    Biocompatible actuators that are capable of controlled movement and can function under biologically relevant conditions are of significant interest in biomedical fields. Previously, we have demonstrated that a composite material of silk biopolymer and the conducting polymer polypyrrole (PPy) can be formed into a bilayer device that can bend under applied voltage. Further, these silk-PPy composites can generate forces comparable to human muscle (>0.1 MPa) making them ideal candidates for interfacing with biological tissues. Here silk-PPy composite films are tested for performance under biologically relevant conditions including exposure to a complex protein serum and biologically relevant temperatures. Free-end bending actuation performance, current response, force generation and, mass degradation were investigated . Preliminary results show that when exposed to proteins and biologically relevant temperatures, these silk-PPy composites show minimal degradation and are able to generate forces and conduct currents comparable to devices tested under standard conditions. NSF.

  2. Native Silk Feedstock as a Model Biopolymer: A Rheological Perspective.

    Science.gov (United States)

    Laity, Peter R; Holland, Chris

    2016-08-08

    Variability in silk's rheology is often regarded as an impediment to understanding or successfully copying the natural spinning process. We have previously reported such variability in unspun native silk extracted straight from the gland of the domesticated silkworm Bombyx mori and discounted classical explanations such as differences in molecular weight and concentration. We now report that variability in oscillatory measurements can be reduced onto a simple master-curve through normalizing with respect to the crossover. This remarkable result suggests that differences between silk feedstocks are rheologically simple and not as complex as originally thought. By comparison, solutions of poly(ethylene-oxide) and hydroxypropyl-methyl-cellulose showed similar normalization behavior; however, the resulting curves were broader than for silk, suggesting greater polydispersity in the (semi)synthetic materials. Thus, we conclude Nature may in fact produce polymer feedstocks that are more consistent than typical man-made counterparts as a model for future rheological investigations.

  3. Synthetic Adhesive Attachment Discs based on Spider Pyriform Silk Architecture

    Science.gov (United States)

    Jain, Dharamdeep; Sahni, Vasav; Dhinojwala, Ali

    2014-03-01

    Among the variety of silks produced by spiders, pyriform silk is used in conjunction with the dragline silk to attach webs to different surfaces. Cob weaver spiders employ different architectural patterns to utilize the pyriform silk and form attachment joints with each pattern having a characteristic adhesive performance. The staple pin architecture is a one of the strongest attachment designs employed by spiders to attach their webs. Here we use a synthetic approach to create the a similar patterned architecture attachment discs on aluminum substrate using thermoplastic polyurethane. Measurable pull off forces are generated when the synthetic discs are peeled off a surface. This innovative adhesive strategy can be a source of design in various biomedical applications. Financial Support from National Science Foundation.

  4. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    NARCIS (Netherlands)

    Yang, Liang; Hedhammar, My; Blom, Tobias; Leifer, Klaus; Johansson, Jan; Habibovic, Pamela; van Blitterswijk, Clemens

    2010-01-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently,

  5. Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava (Psidium guajava) leaf extract

    Energy Technology Data Exchange (ETDEWEB)

    Raghunandan, Deshpande [H.K.E.S' s College of Pharmacy (India); Mahesh, Bedre D. [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India); Basavaraja, S. [Jawaharlal Nehru Centre for Advanced Scientific Research, Veeco-India Nanotechnology Laboratory (India); Balaji, S. D. [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India); Manjunath, S. Y. [Sri Krupa, Institute of Pharmaceutical Science (India); Venkataraman, A., E-mail: raman_chem@rediffmail.com [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India)

    2011-05-15

    Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 {+-} 5 nm from guava (Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV-vis (UV-vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

  6. Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava (Psidium guajava) leaf extract

    International Nuclear Information System (INIS)

    Raghunandan, Deshpande; Mahesh, Bedre D.; Basavaraja, S.; Balaji, S. D.; Manjunath, S. Y.; Venkataraman, A.

    2011-01-01

    Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 ± 5 nm from guava (Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV–vis (UV–vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

  7. Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava ( Psidium guajava) leaf extract

    Science.gov (United States)

    Raghunandan, Deshpande; Mahesh, Bedre D.; Basavaraja, S.; Balaji, S. D.; Manjunath, S. Y.; Venkataraman, A.

    2011-05-01

    Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 ± 5 nm from guava ( Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV-vis (UV-vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

  8. Silk scaffolds in bone tissue engineering: An overview.

    Science.gov (United States)

    Bhattacharjee, Promita; Kundu, Banani; Naskar, Deboki; Kim, Hae-Won; Maiti, Tapas K; Bhattacharya, Debasis; Kundu, Subhas C

    2017-11-01

    Bone tissue plays multiple roles in our day-to-day functionality. The frequency of accidental bone damage and disorder is increasing worldwide. Moreover, as the world population continues to grow, the percentage of the elderly population continues to grow, which results in an increased number of bone degenerative diseases. This increased elderly population pushes the need for artificial bone implants that specifically employ biocompatible materials. A vast body of literature is available on the use of silk in bone tissue engineering. The current work presents an overview of this literature from materials and fabrication perspective. As silk is an easy-to-process biopolymer; this allows silk-based biomaterials to be molded into diverse forms and architectures, which further affects the degradability. This makes silk-based scaffolds suitable for treating a variety of bone reconstruction and regeneration objectives. Silk surfaces offer active sites that aid the mineralization and/or bonding of bioactive molecules that facilitate bone regeneration. Silk has also been blended with a variety of polymers and minerals to enhance its advantageous properties or introduce new ones. Several successful works, both in vitro and in vivo, have been reported using silk-based scaffolds to regenerate bone tissues or other parts of the skeletal system such as cartilage and ligament. A growing trend is observed toward the use of mineralized and nanofibrous scaffolds along with the development of technology that allows to control scaffold architecture, its biodegradability and the sustained releasing property of scaffolds. Further development of silk-based scaffolds for bone tissue engineering, taking them up to and beyond the stage of human trials, is hoped to be achieved in the near future through a cross-disciplinary coalition of tissue engineers, material scientists and manufacturing engineers. The state-of-art of silk biomaterials in bone tissue engineering, covering their wide

  9. Direct transfer of subwavelength plasmonic nanostructures on bioactive silk films.

    Science.gov (United States)

    Lin, Dianmin; Tao, Hu; Trevino, Jacob; Mondia, Jessica P; Kaplan, David L; Omenetto, Fiorenzo G; Dal Negro, Luca

    2012-11-27

    By a reusable transfer fabrication technique, we demonstrate high-fidelity fabrication of metal nanoparticles, optical nanoantennas, and nanohole arrays directly on a functional silk biopolymer. The ability to reproducibly pattern silk biopolymers with arbitrarily complex plasmonic arrays is of importance for a variety of applications in optical biosensing, tissue engineering, cell biology, and the development of novel bio-optoelectronic medical devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. [Study on the chemical constituents of flavones from corn silk].

    Science.gov (United States)

    Zhang, Hui-en; Xu, De-ping

    2007-02-01

    The three flavones were isolated from water extracts of corn silk by chromatography on macroporous resin, polyamide, ODS and Sephadex LH-20. Three compounds were identified as formononetin (7-hydroxy-4'-methoxyisoflavone) ( I ) ,2"-O-alpha-L-rham-nosyl-6-C-( 3-deoxyglucosyl) -3 '-methoxyluteolin( II ) ,2"-O-alpha-L-rhamnosyl-6-C-( 6-deoxy-ax-5-methyl-xylo-hexos-4-ulosyl) -3'-methoxyluteolin( II ). Compounds ( I ) and ( II ) were isolated from the corn silk for the first time.

  11. Nanostructure and molecular mechanics of spider dragline silk protein assemblies

    Science.gov (United States)

    Keten, Sinan; Buehler, Markus J.

    2010-01-01

    Spider silk is a self-assembling biopolymer that outperforms most known materials in terms of its mechanical performance, despite its underlying weak chemical bonding based on H-bonds. While experimental studies have shown that the molecular structure of silk proteins has a direct influence on the stiffness, toughness and failure strength of silk, no molecular-level analysis of the nanostructure and associated mechanical properties of silk assemblies have been reported. Here, we report atomic-level structures of MaSp1 and MaSp2 proteins from the Nephila clavipes spider dragline silk sequence, obtained using replica exchange molecular dynamics, and subject these structures to mechanical loading for a detailed nanomechanical analysis. The structural analysis reveals that poly-alanine regions in silk predominantly form distinct and orderly beta-sheet crystal domains, while disorderly regions are formed by glycine-rich repeats that consist of 31-helix type structures and beta-turns. Our structural predictions are validated against experimental data based on dihedral angle pair calculations presented in Ramachandran plots, alpha-carbon atomic distances, as well as secondary structure content. Mechanical shearing simulations on selected structures illustrate that the nanoscale behaviour of silk protein assemblies is controlled by the distinctly different secondary structure content and hydrogen bonding in the crystalline and semi-amorphous regions. Both structural and mechanical characterization results show excellent agreement with available experimental evidence. Our findings set the stage for extensive atomistic investigations of silk, which may contribute towards an improved understanding of the source of the strength and toughness of this biological superfibre. PMID:20519206

  12. Umbilical cord stem cells released from alginate-fibrin microbeads inside macroporous and biofunctionalized calcium phosphate cement for bone regeneration

    Science.gov (United States)

    Chen, Wenchuan; Zhou, Hongzhi; Weir, Michael D.; Bao, Chongyun; Xu, Hockin H.K.

    2012-01-01

    The need for bone repair has increased as the population ages. The objectives of this study were to (1) develop a novel biofunctionalized and macroporous calcium phosphate cement (CPC) containing alginate-fibrin microbeads encapsulating human umbilical cord mesenchymal stem cells (hUCMSCs); and (2) investigate hUCMSC proliferation and osteogenic differentiation inside CPC for the first time. Macroporous CPC was developed using calcium phosphate powders, chitosan, and gas-foaming porogen. Five types of CPCs were fabricated: CPC control, CPC + 0.05% fibronectin (Fn), CPC + 0.1% Fn, CPC + 0.1% Arg-Gly-Asp (RGD), and CPC + 0.1% Fn + 0.1% RGD. Alginate-fibrin microbeads containing 106 hUCMSCs/mL were encapsulated in the CPC paste. After CPC had set, the degradable microbeads released hUCMSCs inside CPC. hUCMScs proliferated inside CPC, with cell density at 21 d being 4-fold that at 1 d. CPC + 0.1% RGD had the highest cell density, which was 4-fold that of CPC control. The released cells differentiated into the osteogenic lineage and synthesized bone minerals. hUCMSCs inside the CPC + 0.1% RGD construct had gene expressions of alkaline phosphatase (ALP), osteocalcin (OC) and collagen I, which were twice those of CPC control. Mineral synthesis by hUCMSCs inside the CPC + 0.1% RGD construct was 2-fold that in CPC control. RGD and Fn incorporation in CPC did not compromise the strength of CPC, which matched the reported strength of cancellous bone. In conclusion, degradable microbeads released the hUCMSCs which proliferated, differentiated and synthesized minerals inside the macroporous CPC for the first time. CPC with RGD greatly enhanced cell functions. The novel biofunctionalized and macroporous CPC-microbead-hUCMSC construct is promising for bone tissue engineering applications. PMID:22391411

  13. ARM-microcontroller based portable nitrite electrochemical analyzer using cytochrome c reductase biofunctionalized onto screen printed carbon electrode.

    Science.gov (United States)

    Santharaman, Paulraj; Venkatesh, Krishna Arun; Vairamani, Kanagavel; Benjamin, Alby Robson; Sethy, Niroj K; Bhargava, Kalpana; Karunakaran, Chandran

    2017-04-15

    Nitrite (NO 2 - ) supplementation limits hypoxia-induced oxidative stress and activates the alternate NO pathway which may partially account for the nitrite-mediated cardioprotection. So, sensitive and selective biosensors with point-of-care devices need to be explored to detect the physiological nitrite level due to its important role in human pathophysiology. In this work, cytochrome c reductase (CcR) biofunctionalized self assembled monolayer (SAM) functionalized on gold nanoparticles (GNPs) in polypyrrole (PPy) nanocomposite onto the screen printed carbon electrode (SPCE) was investigated as a biosensor for the detection of nitrite based on its electrochemical and catalytic properties. CcR was covalently coupled with SAM layers on GNPs by using EDC and NHS. Direct electrochemical response of CcR biofunctionalized electrodes showed a couple of well-defined and nearly reversible cyclic voltammetric peaks at -0.34 and -0.45 vs. Ag/AgCl. Under optimal conditions, the biosensor could be used for the determination of NO 2 - with a linear range from 0.1-1600µm and a detection limit of 60nM with a sensitivity of 0.172µAµM -1 cm -2 . Further, we have designed and developed a novel and cost effective portable electrochemical analyzer for the measurement of NO 2 - in hypoxia induced H9c2 cardiac cells using ARM microcontroller. The results obtained here using the developed portable electrochemical nitrite analyzer were also compared with the standard cyclic voltammetry instrument and found in agreement with each other. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber.

    Science.gov (United States)

    Yang, Jen Ming; Yang, Jhe Hao; Tsou, Shu Chun; Ding, Chian Hua; Hsu, Chih Chin; Yang, Kai Chiang; Yang, Chun Chen; Chen, Ko Shao; Chen, Szi Wen; Wang, Jong Shyan

    2016-09-01

    To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1day seeded. Cell-cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

  15. Flexible and wearable electronic silk fabrics for human physiological monitoring

    Science.gov (United States)

    Mao, Cuiping; Zhang, Huihui; Lu, Zhisong

    2017-09-01

    The development of textile-based devices for human physiological monitoring has attracted tremendous interest in recent years. However, flexible physiological sensing elements based on silk fabrics have not been realized. In this paper, ZnO nanorod arrays are grown in situ on reduced graphene oxide-coated silk fabrics via a facile electro-deposition method for the fabrication of silk-fabric-based mechanical sensing devices. The data show that well-aligned ZnO nanorods with hexagonal wurtzite crystalline structures are synthesized on the conductive silk fabric surface. After magnetron sputtering of gold electrodes, silk-fabric-based devices are produced and applied to detect periodic bending and twisting. Based on the electric signals, the deformation and release processes can be easily differentiated. Human arterial pulse and respiration can also be real-time monitored to calculate the pulse rate and respiration frequency, respectively. Throat vibrations during coughing and singing are detected to demonstrate the voice recognition capability. This work may not only help develop silk-fabric-based mechanical sensing elements for potential applications in clinical diagnosis, daily healthcare monitoring and voice recognition, but also provide a versatile method for fabricating textile-based flexible electronic devices.

  16. Compliant threads maximize spider silk connection strength and toughness

    Science.gov (United States)

    Meyer, Avery; Pugno, Nicola M.; Cranford, Steven W.

    2014-01-01

    Millions of years of evolution have adapted spider webs to achieve a range of functionalities, including the well-known capture of prey, with efficient use of material. One feature that has escaped extensive investigation is the silk-on-silk connection joints within spider webs, particularly from a structural mechanics perspective. We report a joint theoretical and computational analysis of an idealized silk-on-silk fibre junction. By modifying the theory of multiple peeling, we quantitatively compare the performance of the system while systematically increasing the rigidity of the anchor thread, by both scaling the stress–strain response and the introduction of an applied pre-strain. The results of our study indicate that compliance is a virtue—the more extensible the anchorage, the tougher and stronger the connection becomes. In consideration of the theoretical model, in comparison with rigid substrates, a compliant anchorage enormously increases the effective adhesion strength (work required to detach), independent of the adhered thread itself, attributed to a nonlinear alignment between thread and anchor (contact peeling angle). The results can direct novel engineering design principles to achieve possible load transfer from compliant fibre-to-fibre anchorages, be they silk-on-silk or another, as-yet undeveloped, system. PMID:25008083

  17. Transmission Electron Microscopy of Bombyx Mori Silk Fibers

    Science.gov (United States)

    Shen, Y.; Martin, D. C.

    1997-03-01

    The microstructure of B. Mori silk fibers before and after degumming was examined by TEM, selected area electron diffraction (SAED), WAXS and low voltage SEM. SEM micrographs of the neat cocoon revealed a network of pairs of twisting filaments. After degumming, there were only individual filaments showing a surface texture consistent with an oriented fibrillar structure in the fiber interior. WAXS patterns confirmed the oriented beta-sheet crystal structure common to silkworm and spider silks. Low dose SAED results were fully consistent with the WAXS data, and revealed that the crystallographic texture did not vary significantly across the fiber diameter. TEM observations of microtomed fiber cross sections indicated a somewhat irregular shape, and also revealed a 0.5-2 micron sericin coating which was removed by the degumming process. TEM observations of the degummed silk fiber showed banded features with a characteristic spacing of nominally 600 nm along the fiber axis. These bands were oriented in a roughly parabolic or V-shape pointing along one axis within a given fiber. We hypothesize that this orientation is induced by the extrusion during the spinning process. Equatorial DF images revealed that axial and lateral sizes of the β-sheet crystallites in silk fibroin ranged from 20 to 170 nm and from 1 to 24 nm, respectively. Crazes developed in the degummed silk fiber parallel to the fiber direction. The formation of these crazes suggests that there are significant lateral interactions between fibrils in silk fibers.

  18. Engagement and contestation: The entangled imagery of the Silk Road

    Directory of Open Access Journals (Sweden)

    Timur Dadabaev

    2018-03-01

    Full Text Available There is considerable debate over how and in what form Central Asian (CA states should conduct relations among each other and with other post-Soviet states. The notion of the “Silk Road” has become one of the symbols of extended economic and political cooperation. Notably, however, Japan (Silk Road Diplomacy, 1996–1999, China (One Belt, One Road [OBOR] or the Belt and Road initiative [BRI] and South Korea (Silk Road Strategy, 2011 have used the rhetoric of reviving the Silk Road to imply closer engagement with the CA region but with different connotations. This paper focuses on the formation of this discourse of engagement with the CA region through the notion of the Silk Road in China, South Korea and Japan and raises the following questions: What are the approaches that facilitate the most effective ways of engaging CA states under this “Silk Road” rhetoric? What are the principles that have detrimental effects on the successes and failures of the engagement of China, Japan and South Korea? The primary objective of this paper is to address these questions and to stimulate debate among both academics and policy makers on the formats of engagement and cooperation in Eurasia.

  19. Development and Evaluation of Isoniazid Loaded Silk Fibroin Microsphere

    Directory of Open Access Journals (Sweden)

    Narinder Singh

    Full Text Available Aim: Current experimental investigation is dedicated to prepare microspheres with small size and good sphericity by Phase Separation method using Isoniazid (INH as model drug. Silk fibroin has unique intrinsic qualities like biodegradability, biocompatibility or release properties and their tunable drug loading capacity. The delivery loading proficiency of the drug molecules in silk spheres be contingent on their charge, and hydrophobicity or subsequent in altered drug release profiles. Methods: In the present work Isoniazid loaded silk fibroin microsphere was prepared by using phase separation method. Microsphere was evaluated for Ultraviolet-visible spectroscopy, Fourier Transform infrared spectroscopy, Entrapment efficiency, Scanning electron microscopy Studies. Results: Scanning electron microscopy studies revealed that Isoniazid Loaded Silk Fibroin Microspheres were spherical. Entrapment Efficiency of Isoniazid loaded Microspheres of different Formulation from F1 to F5 was in range of 53 to 68 %. F3 showed 68.47 % entrapment Efficiency and the optimized formulation drug release was 93.56 % at 24 hours. Conclusion: Experimental report disclosed a new aqueous based formulation method for silk spheres with controllable shape or size and sphere. Isoniazid loaded silk microspheres may act as ideal nano formulation with elaborated studies.

  20. Recombinant spider silk genetically functionalized with affinity domains.

    Science.gov (United States)

    Jansson, Ronnie; Thatikonda, Naresh; Lindberg, Diana; Rising, Anna; Johansson, Jan; Nygren, Per-Åke; Hedhammar, My

    2014-05-12

    Functionalization of biocompatible materials for presentation of active protein domains is an area of growing interest. Herein, we describe a strategy for functionalization of recombinant spider silk via gene fusion to affinity domains of broad biotechnological use. Four affinity domains of different origin and structure; the IgG-binding domains Z and C2, the albumin-binding domain ABD, and the biotin-binding domain M4, were all successfully produced as soluble silk fusion proteins under nondenaturing purification conditions. Silk films and fibers produced from the fusion proteins were demonstrated to be chemically and thermally stable. Still, the bioactive domains are concluded to be folded and accessible, since their respective targets could be selectively captured from complex samples, including rabbit serum and human plasma. Interestingly, materials produced from mixtures of two different silk fusion proteins displayed combined binding properties, suggesting that tailor-made materials with desired stoichiometry and surface distributions of several binding domains can be produced. Further, use of the IgG binding ability as a general mean for presentation of desired biomolecules could be demonstrated for a human vascular endothelial growth factor (hVEGF) model system, via a first capture of anti-VEGF IgG to silk containing the Z-domain, followed by incubation with hVEGF. Taken together, this study demonstrates the potential of recombinant silk, genetically functionalized with affinity domains, for construction of biomaterials capable of presentation of almost any desired biomolecule.

  1. Determination of Na, Mn and Cu in cocoon, raw silk and degummed silk by nondestructive activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Maki, Y; Ishiguro, Y [Industrial Research Inst. of Kanagawa Prefecture, Yokohama (Japan)

    1976-01-01

    The sodium, manganese and copper contained in cocoons, raw silk and degummed silk thread were determined by the nondestructive activation analysis. After each sample was irradiated with the thermal neutron flux of 5 x 10/sup 11/n/cm/sup 2/.sec, its ..gamma..-ray spectrum was measured with a NaI(Tl) detector. With the photoelectric peaks at 511 keV (/sup 64/Cu), 1368 keV (/sup 24/Na) and 847 keV (/sup 56/Mn), each element was quantitatively determined and its content was obtained. The measurement of the ..gamma..-ray spectra of samples with a Ge (Li) detector proved the presence of An, Sb, Fe, Zn, Cr, Sc, Co, etc. Large amounts of Na and Cu were detected in the sericin portion of cocoons, and the adhesion of Cu from a reeling-off machine to raw silk was also observed during the process of degumming cocoons to make raw silk.

  2. Electricity from the Silk Cocoon Membrane

    Science.gov (United States)

    Tulachan, Brindan; Meena, Sunil Kumar; Rai, Ratan Kumar; Mallick, Chandrakant; Kusurkar, Tejas Sanjeev; Teotia, Arun Kumar; Sethy, Niroj Kumar; Bhargava, Kalpana; Bhattacharya, Shantanu; Kumar, Ashok; Sharma, Raj Kishore; Sinha, Neeraj; Singh, Sushil Kumar; Das, Mainak

    2014-01-01

    Silk cocoon membrane (SCM) is an insect engineered structure. We studied the electrical properties of mulberry (Bombyx mori) and non-mulberry (Tussar, Antheraea mylitta) SCM. When dry, SCM behaves like an insulator. On absorbing moisture, it generates electrical current, which is modulated by temperature. The current flowing across the SCM is possibly ionic and protonic in nature. We exploited the electrical properties of SCM to develop simple energy harvesting devices, which could operate low power electronic systems. Based on our findings, we propose that the temperature and humidity dependent electrical properties of the SCM could find applications in battery technology, bio-sensor, humidity sensor, steam engines and waste heat management. PMID:24961354

  3. Silla Art and the Silk Road

    Directory of Open Access Journals (Sweden)

    Kwangshik Choe

    2014-02-01

    Full Text Available Western and Indian features found in Silla art, whether they came from the Western border regions of China or through a connection with China, it is recognized that there was both a direct and indirect a relationship between Silla, the West, and India. Many scholars have been interested in these aspects, conducting various studies as these factors played a large part in defining the origin of ancient culture and the process of harmonization between cultures. Through the Silk Road scholars are able to identify how Western cultures and civilizations were introduced to the Silla Dynasty. As the Korean peninsula has been a nexus for exchange between the East and the West, this paper aims to understand the meaning of the “Silk Road” and examines the actual state of cultural exchange at this historical site. Through artifacts excavated from Hwangnamdae-ch’ong (especially glass products, it has been determined that the Western and Western bordering countries of China culturally influenced the art of Silla. They also clearly prove that Buddhist sculptures from India and the Western bordering countries of China had a great impact on Silla art as well. Through these findings, it can be confirmed that from ancient times the influence of many cultures including China, the West, and the Western bordering countries of China had an impact on Korean culture. Particularly, Indian Buddhism which flowed into China and the Korea peninsula participated in the development of Silla culture and also played a significant role in the formation of traditional Korean culture.

  4. The Potential of Silk and Silk-Like Proteins as Natural Mucoadhesive Biopolymers for Controlled Drug Delivery.

    Science.gov (United States)

    Brooks, Amanda E

    2015-01-01

    Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1) deliver sensitive biologic molecules, (2) promote intimate contact between the mucosa and the drug, and (3) prolong the drug's local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery.

  5. The potential of silk and silk-like proteins as natural mucoadhesive biopolymers for controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Amanda E Brooks

    2015-11-01

    Full Text Available Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1 deliver sensitive biologic molecules, (2 promote intimate contact between the mucosa and the drug, and (3 prolong the drug’s local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery.

  6. Bio-functionalizing of α-MnO{sub 2} nanorods with natural L-amino acids: A favorable adsorbent for the removal of Cd(II) ions

    Energy Technology Data Exchange (ETDEWEB)

    Mallakpour, Shadpour, E-mail: mallak@cc.iut.ac.ir [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Motirasoul, Forough [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of)

    2017-04-15

    α-MnO{sub 2} nanorods were prepared by hydrothermal method and then the surface of these nanorods were covalently biofunctionalized with natural L-amino acids (alanine, phenylalanine, leucine, isoleucine, methionine, and valine). The modified α-MnO{sub 2} nanorods were analyzed by Fourier transform infrared spectroscopy and X-ray diffraction. Morphological studies were carried out by field emission scanning electron microscopy and transmission electron microscopy. The morphology of nanorods was improved after biofunctionalization and aggregation was reduced. In addition, the thermal gravimetric analysis was used for demonstrating a successful grafting of amino acids to the surface of α-MnO{sub 2} nanorods and determine the degree of functionalization. The amount of amino acids grafted onto α-MnO{sub 2} surface was estimated to be 5–32 wt%. Finally, the α-MnO{sub 2} and α-MnO{sub 2}-L-valine were investigated as adsorbents for the removal of cadmium ions from aqueous solution. The results showed that they have a potential to be used as effective adsorbents for cadmium ions removal from the aqueous solution. The equilibrium adsorption data showed the best fit for the pseudo-second-order and the Freundlich models. - Highlights: • α-MnO{sub 2} nanorods were biofunctionalized with natural L-amino acids. • Biofunctionalized α-MnO{sub 2} nanorods by solvothermal strategy were fully characterized. • Cadmium adsorption property of α-MnO{sub 2} and α-MnO{sub 2}-L-valine was studied.

  7. Natural Silk as a Photonics Component: a Study on Its Light Guiding and Nonlinear Optical Properties

    OpenAIRE

    Kujala, Sami; Mannila, Anna; Karvonen, Lasse; Kieu, Khanh; Sun, Zhipei

    2016-01-01

    Silk fibers are expected to become a pathway to biocompatible and bioresorbable waveguides, which could be used to deliver localized optical power for various applications, e.g., optical therapy or imaging inside living tissue. Here, for the first time, the linear and nonlinear optical properties of natural silk fibers have been studied. The waveguiding properties of silk fibroin of largely unprocessed Bombyx mori silkworm silk are assessed using two complementary methods, and found to be on ...

  8. Traveling the Silk Road: A Measurement of a Large Anonymous Online Marketplace

    Science.gov (United States)

    2012-11-28

    Silk Road, an anonymous, international online marketplace that operates as a Tor hidden service and uses Bitcoin as its exchange currency. We gather...analysis of Silk Road, an anonymous, international on- line marketplace that operates as a Tor hidden service and uses Bitcoin as its exchange currency. We...anonymity, Silk Road needs to also preserve payment anonymity. To that effect, Silk Road only supports Bitcoin (BTC, [30]) as a trading currency

  9. Multifunctional surface modification of silk fabric via graphene oxide repeatedly coating and chemical reduction method

    Science.gov (United States)

    Cao, Jiliang; Wang, Chaoxia

    2017-05-01

    Multifunctional silk fabrics with electrical conductive, anti-ultraviolet and water repellent were successfully prepared by surface modification with graphene oxide (GO). The yellow-brown GO deposited on the surface of silk fabric was converted into graphitic black reduced graphene (RGO) by sodium hydrosulfite. The surface properties of silk fabrics were changed by repeatedly RGO coating process, which have been proved by SEM and XPS. The SEM results showed that the RGO sheets were successive form a continuously thin film on the surface of silk fabrics, and the deposition of GO or RGO also can be proved by XPS. The electrical conductivity was tested by electrical surface resistance value of the silk fabric, the surface resistance decreased with increasing of RGO surface modification times, and a low surface resistance value reached to 3.24 KΩ cm-1 after 9 times of modification, indicating the silk obtained excellent conductivity. The UPF value of one time GO modification silk fabric (silk-1RGO) was enhanced significantly to 24.45 in comparison to 10.40 of original silk. The contact angle of RGO coating silk samples was all above of 120°. The durability of RGO coated silk fabrics was tested by laundering. The electrical surface resistance of silk-4RGO (65.74 KΩ cm-1), silk-6RGO (15.54 KΩ cm-1) and silk-8RGO (3.86 KΩ cm-1) fabrics was up to 86.82, 22.30 and 6.57 KΩ cm-1 after 10 times of standard washing, respectively. The UPF value, contact angle and color differences of RGO modified silk fabric slightly changed before and after 10 times of standard washing. Therefore, the washing fastness of electric conduction, anti-ultraviolet and water repellent multifunctional silk fabrics was excellent.

  10. Solubilization of spider silk proteins and its structural analysis using Fourier transform infrared spectroscopy

    Science.gov (United States)

    Osbin, K.; Jayan, Manuel; Bhadrakumari, S.; Predeep, P.

    2017-06-01

    This study investigates the presence of various amide bands present in different spider silk species, which provides extraordinary physical properties. Three different spider silks were collected from Western Ghats region. The collected spider silks samples belonging to the spider Heteropoda venatoria (species 1), Hersilia savignyi (species 2) and Pholcus phalangioides (species 3). Fourier transform infrared (FTIR) spectra reveals the protein peaks in the amide I, II, and III regions in all the three types of spider silk species.

  11. Synthetic Spider Silk Production on a Laboratory Scale

    Science.gov (United States)

    Hsia, Yang; Gnesa, Eric; Pacheco, Ryan; Kohler, Kristin; Jeffery, Felicia; Vierra, Craig

    2012-01-01

    As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation biomaterials with high performance properties. The development of these new structural materials must be rapid, cost-efficient and involve processing methodologies and products that are environmentally friendly and sustainable. Spiders spin a multitude of different fiber types with diverse mechanical properties, offering a rich source of next generation engineering materials for biomimicry that rival the best manmade and natural materials. Since the collection of large quantities of natural spider silk is impractical, synthetic silk production has the ability to provide scientists with access to an unlimited supply of threads. Therefore, if the spinning process can be streamlined and perfected, artificial spider fibers have the potential use for a broad range of applications ranging from body armor, surgical sutures, ropes and cables, tires, strings for musical instruments, and composites for aviation and aerospace technology. In order to advance the synthetic silk production process and to yield fibers that display low variance in their material properties from spin to spin, we developed a wet-spinning protocol that integrates expression of recombinant spider silk proteins in bacteria, purification and concentration of the proteins, followed by fiber extrusion and a mechanical post-spin treatment. This is the first visual representation that reveals a step-by-step process to spin and analyze artificial silk fibers on a laboratory scale. It also provides details to minimize the introduction of variability among fibers spun from the same spinning dope. Collectively, these methods will propel the process of artificial silk production, leading to higher quality fibers that surpass natural spider silks. PMID:22847722

  12. Molecular mechanics of silk nanostructures under varied mechanical loading.

    Science.gov (United States)

    Bratzel, Graham; Buehler, Markus J

    2012-06-01

    Spider dragline silk is a self-assembling tunable protein composite fiber that rivals many engineering fibers in tensile strength, extensibility, and toughness, making it one of the most versatile biocompatible materials and most inviting for synthetic mimicry. While experimental studies have shown that the peptide sequence and molecular structure of silk have a direct influence on the stiffness, toughness, and failure strength of silk, few molecular-level analyses of the nanostructure of silk assemblies, in particular, under variations of genetic sequences have been reported. In this study, atomistic-level structures of wildtype as well as modified MaSp1 protein from the Nephila clavipes spider dragline silk sequences, obtained using an in silico approach based on replica exchange molecular dynamics and explicit water molecular dynamics, are subjected to simulated nanomechanical testing using different force-control loading conditions including stretch, pull-out, and peel. The authors have explored the effects of the poly-alanine length of the N. clavipes MaSp1 peptide sequence and identify differences in nanomechanical loading conditions on the behavior of a unit cell of 15 strands with 840-990 total residues used to represent a cross-linking β-sheet crystal node in the network within a fibril of the dragline silk thread. The specific loading condition used, representing concepts derived from the protein network connectivity at larger scales, have a significant effect on the mechanical behavior. Our analysis incorporates stretching, pull-out, and peel testing to connect biochemical features to mechanical behavior. The method used in this study could find broad applications in de novo design of silk-like tunable materials for an array of applications. Copyright © 2011 Wiley Periodicals, Inc.

  13. Correlation between fibroin amino acid sequence and physical silk properties.

    Science.gov (United States)

    Fedic, Robert; Zurovec, Michal; Sehnal, Frantisek

    2003-09-12

    The fiber properties of lepidopteran silk depend on the amino acid repeats that interact during H-fibroin polymerization. The aim of our research was to relate repeat composition to insect biology and fiber strength. Representative regions of the H-fibroin genes were sequenced and analyzed in three pyralid species: wax moth (Galleria mellonella), European flour moth (Ephestia kuehniella), and Indian meal moth (Plodia interpunctella). The amino acid repeats are species-specific, evidently a diversification of an ancestral region of 43 residues, and include three types of regularly dispersed motifs: modifications of GSSAASAA sequence, stretches of tripeptides GXZ where X and Z represent bulky residues, and sequences similar to PVIVIEE. No concatenations of GX dipeptide or alanine, which are typical for Bombyx silkworms and Antheraea silk moths, respectively, were found. Despite different repeat structure, the silks of G. mellonella and E. kuehniella exhibit similar tensile strength as the Bombyx and Antheraea silks. We suggest that in these latter two species, variations in the repeat length obstruct repeat alignment, but sufficiently long stretches of iterated residues get superposed to interact. In the pyralid H-fibroins, interactions of the widely separated and diverse motifs depend on the precision of repeat matching; silk is strong in G. mellonella and E. kuehniella, with 2-3 types of long homogeneous repeats, and nearly 10 times weaker in P. interpunctella, with seven types of shorter erratic repeats. The high proportion of large amino acids in the H-fibroin of pyralids has probably evolved in connection with the spinning habit of caterpillars that live in protective silk tubes and spin continuously, enlarging the tubes on one end and partly devouring the other one. The silk serves as a depot of energetically rich and essential amino acids that may be scarce in the diet.

  14. 'Surfing the Silk Road': a study of users' experiences.

    Science.gov (United States)

    Van Hout, Marie Claire; Bingham, Tim

    2013-11-01

    The online drug marketplace called 'Silk Road' has operated anonymously on the 'Deep Web' since 2011. It is accessible through computer encrypting software (Tor) and is supported by online transactions using peer to peer anonymous and untraceable crypto-currency (Bit Coins). The study aimed to describe user motives and realities of accessing, navigating and purchasing on the 'Silk Road' marketplace. Systematic online observations, monitoring of discussion threads on the site during four months of fieldwork and analysis of anonymous online interviews (n=20) with a convenience sample of adult 'Silk Road' users was conducted. The majority of participants were male, in professional employment or in tertiary education. Drug trajectories ranged from 18 months to 25 years, with favourite drugs including MDMA, 2C-B, mephedrone, nitrous oxide, ketamine, cannabis and cocaine. Few reported prior experience of online drug sourcing. Reasons for utilizing 'Silk Road' included curiosity, concerns for street drug quality and personal safety, variety of products, anonymous transactioning, and ease of product delivery. Vendor selection appeared to be based on trust, speed of transaction, stealth modes and quality of product. Forums on the site provided user advice, trip reports, product and transaction reviews. Some users reported solitary drug use for psychonautic and introspective purposes. A minority reported customs seizures, and in general a displacement away from traditional drug sourcing (street and closed markets) was described. Several reported intentions to commence vending on the site. The study provides an insight into 'Silk Road' purchasing motives and processes, the interplay between traditional and 'Silk Road' drug markets, the 'Silk Road' online community and its communication networks. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Electrospun nanofibrous materials for tissue engineering and drug delivery

    Directory of Open Access Journals (Sweden)

    Wenguo Cui, Yue Zhou and Jiang Chang

    2010-01-01

    Full Text Available The electrospinning technique, which was invented about 100 years ago, has attracted more attention in recent years due to its possible biomedical applications. Electrospun fibers with high surface area to volume ratio and structures mimicking extracellular matrix (ECM have shown great potential in tissue engineering and drug delivery. In order to develop electrospun fibers for these applications, different biocompatible materials have been used to fabricate fibers with different structures and morphologies, such as single fibers with different composition and structures (blending and core-shell composite fibers and fiber assemblies (fiber bundles, membranes and scaffolds. This review summarizes the electrospinning techniques which control the composition and structures of the nanofibrous materials. It also outlines possible applications of these fibrous materials in skin, blood vessels, nervous system and bone tissue engineering, as well as in drug delivery.

  16. Fluorescent and Colorimetric Electrospun Nanofibers for Heavy-Metal Sensing

    Directory of Open Access Journals (Sweden)

    Idelma A. A. Terra

    2017-12-01

    Full Text Available The accumulation of heavy metals in the human body and/or in the environment can be highly deleterious for mankind, and currently, considerable efforts have been made to develop reliable and sensitive techniques for their detection. Among the detection methods, chemical sensors appear as a promising technology, with emphasis on systems employing optically active nanofibers. Such nanofibers can be obtained by the electrospinning technique, and further functionalized with optically active chromophores such as dyes, conjugated polymers, carbon-based nanomaterials and nanoparticles, in order to produce fluorescent and colorimetric nanofibers. In this review we survey recent investigations reporting the use of optically active electrospun nanofibers in sensors aiming at the specific detection of heavy metals using colorimetry and fluorescence methods. The examples given in this review article provide sufficient evidence of the potential of optically electrospun nanofibers as a valid approach to fabricate highly selective and sensitive optical sensors for fast and low-cost detection of heavy metals.

  17. Electrospun materials for affinity-based engineering and drug delivery

    International Nuclear Information System (INIS)

    Sill, T J; Von Recum, H A

    2015-01-01

    Electrospinning is a process which can quickly and cheaply create materials of high surface to volume and aspect ratios from many materials, however in application toward drug delivery this can be a strong disadvantage as well. Diffusion of drug is proportional to the thickness of that device. In moving from macro to micro to nano-sized electrospun materials drug release rates change to profiles that are too fast to be therapeutically beneficial. In this work we use molecular interactions to further control the rate of release beyond that capable of diffusion alone. To do this we create materials with molecular pockets, which can 'hold' therapeutic drugs through a reversible interaction such as a host/guest complexation. Through these complexes we show we are able to impact delivery of drug from electrospun materials, and also apply them in tissue engineering for the reversible presentation of biomolecules on a fiber surface. (paper)

  18. Electrospun Phospholipid Fibers as Micro-Encapsulation and Antioxidant Matrices.

    Science.gov (United States)

    Shekarforoush, Elhamalsadat; Mendes, Ana C; Baj, Vanessa; Beeren, Sophie R; Chronakis, Ioannis S

    2017-10-17

    Electrospun phospholipid (asolectin) microfibers were investigated as antioxidants and encapsulation matrices for curcumin and vanillin. These phospholipid microfibers exhibited antioxidant properties which increased after the encapsulation of both curcumin and vanillin. The total antioxidant capacity (TAC) and the total phenolic content (TPC) of curcumin/phospholipid and vanillin/phospholipid microfibers remained stable over time at different temperatures (refrigerated, ambient) and pressures (vacuum, ambient). ¹H-NMR confirmed the chemical stability of both encapsulated curcumin and vanillin within phospholipid fibers. Release studies in aqueous media revealed that the phenolic bioactives were released mainly due to swelling of the phospholipid fiber matrix over time. The above studies confirm the efficacy of electrospun phospholipid microfibers as encapsulation and antioxidant systems.

  19. Electrospun Phospholipid Fibers as Micro-Encapsulation and Antioxidant Matrices

    Directory of Open Access Journals (Sweden)

    Elhamalsadat Shekarforoush

    2017-10-01

    Full Text Available Electrospun phospholipid (asolectin microfibers were investigated as antioxidants and encapsulation matrices for curcumin and vanillin. These phospholipid microfibers exhibited antioxidant properties which increased after the encapsulation of both curcumin and vanillin. The total antioxidant capacity (TAC and the total phenolic content (TPC of curcumin/phospholipid and vanillin/phospholipid microfibers remained stable over time at different temperatures (refrigerated, ambient and pressures (vacuum, ambient. 1H-NMR confirmed the chemical stability of both encapsulated curcumin and vanillin within phospholipid fibers. Release studies in aqueous media revealed that the phenolic bioactives were released mainly due to swelling of the phospholipid fiber matrix over time. The above studies confirm the efficacy of electrospun phospholipid microfibers as encapsulation and antioxidant systems.

  20. [Engineered spider silk: the intelligent biomaterial of the future. Part I].

    Science.gov (United States)

    Florczak, Anna; Piekoś, Konrad; Kaźmierska, Katarzyna; Mackiewicz, Andrzej; Dams-Kozłowska, Hanna

    2011-06-17

    The unique properties of spider silk such as strength, extensibility, toughness, biocompatibility and biodegradability are the reasons for the recent development in silk biomaterial technology. For a long time scientific progress was impeded by limited access to spider silk. However, the development of the molecular biology strategy was a breaking point in synthetic spider silk protein design. The sequences of engineered spider silk are based on the consensus motives of the corresponding natural equivalents. Moreover, the engineered silk proteins may be modified in order to gain a new function. The strategy of the hybrid proteins constructed on the DNA level combines the sequence of engineered silk, which is responsible for the biomaterial structure, with the sequence of polypeptide which allows functionalization of the silk biomaterial. The functional domains may comprise receptor binding sites, enzymes, metal or sugar binding sites and others. Currently, advanced research is being conducted, which on the one hand focuses on establishing the particular silk structure and understanding the process of silk thread formation in nature. On the other hand, there are attempts to improve methods of engineered spider silk protein production. Due to acquired knowledge and recent progress in synthetic protein technology, the engineered silk will turn into intelligent biomaterial of the future, while its industrial production scale will trigger a biotechnological revolution.

  1. Effects of Japanese beetle (Coleoptera: Scarabaeidae) and silk clipping in field corn.

    Science.gov (United States)

    Steckel, Sandy; Stewart, S D; Tindall, K V

    2013-10-01

    Japanese beetle (Popillia japonica Newman) is an emerging silk-feeding insect found in fields in the lower Corn Belt and Midsouthern United States. Studies were conducted in 2010 and 2011 to evaluate how silk clipping in corn affects pollination and yield parameters. Manually clipping silks once daily had modest effects on yield parameters. Sustained clipping by either manually clipping silks three times per day or by caging Japanese beetles onto ears affected total kernel weight if it occurred during early silking (R1 growth stage). Manually clipping silks three times per day for the first 5 d of silking affected the number of kernels per ear, total kernel weight, and the weight of individual kernels. Caged beetles fed on silks and, depending on the number of beetles caged per ear, reduced the number of kernels per ear. Caging eight beetles per ear significantly reduced total kernel weight compared with noninfested ears. Drought stress before anthesis appeared to magnify the impact of silk clipping by Japanese beetles. There was evidence of some compensation for reduced pollination by increasing the size of pollinated kernels within the ear. Our results showed that it requires sustained silk clipping during the first week of silking to have substantial impacts on pollination and yield parameters, at least under good growing conditions. Some states recommend treating for Japanese beetle when three Japanese beetles per ear are found, silks are clipped to < 13 mm, and pollination is < 50% complete, and that recommendation appears to be adequate.

  2. The inflammatory responses to silk films in vitro and in vivo

    NARCIS (Netherlands)

    Meinel, L.; Hofmann, S.; Karageorgiou, V.; Kirker-Head, C.; McCool, J.; Gronowicz, G.; Zichner, L.; Langer, R.; Vunjak-Novakovic, G.; Kaplan, D.L.

    2005-01-01

    Silks have a long history of biomedical use as sutures. Silk can be purified, chemically modified to attach RGD sequences and processed into highly porous scaffolds for tissue engineering. We report biocompatibility studies of silk films (with or without covalently bound RGD) that were seeded with

  3. The effect of thyroxine on silk gland and the effect of two thyroxine ...

    African Journals Online (AJOL)

    The influence of feeding mulberry leaves treated with thyroxine to the growth of the silk gland, and the effect of two different mulberry species, that is, Morus nigra and Morus multicaulis treated with thyroxine on silk quality in the silkworm were studied. The silk glands from thyroxine treated Bombyx mori larvae weighed ...

  4. Electrospun Phospholipid Fibers as Micro-Encapsulation and Antioxidant Matrices

    DEFF Research Database (Denmark)

    Shekarforoush, Elhamalsadat; Mendes, Ana Carina Loureiro; Baj, Vanessa

    2017-01-01

    Electrospun phospholipid (asolectin) microfibers were investigated as antioxidants and encapsulation matrices for curcumin and vanillin. These phospholipid microfibers exhibited antioxidant properties which increased after the encapsulation of both curcumin and vanillin. The total antioxidant...... capacity (TAC) and the total phenolic content (TPC) of curcumin/phospholipid and vanillin/phospholipid microfibers remained stable over time at different temperatures (refrigerated, ambient) and pressures (vacuum, ambient). ¹H-NMR confirmed the chemical stability of both encapsulated curcumin and vanillin...

  5. Antibacterial performance of bovine lactoferrin-fish gelatine electrospun nanocomposites

    OpenAIRE

    Padrão, Jorge; Machado, Raul; Casal, Margarida; Rodrigues, L. R.; Dourado, Fernando; Lanceros-Méndez, S.; Sencadas, V.

    2014-01-01

    Antibacterial performance of bovine lactoferrin-fish gelatine electrospun nanocomposites The alarming increase of antibiotic resistant microorganisms urged the development and synthesis of novel antimicrobial biomaterials, to be employed in a broad range of applications, ranging from food casings to medical devices [1 – 3]. This work describes the processing and characterization of an innovative fully biobased eletrctrospun nanocomposite material displaying antibacterial properties. Its c...

  6. Graphitic nanofibres from electrospun solutions of PAN in dimethylsulphoxide

    OpenAIRE

    Kurban, Zeynep; Lovell, Arthur; Jenkins, Derek; Bennington, Steve; Loader, Ian; Schober, Alex; Skipper, Neal

    2009-01-01

    Homogenous graphitic nanofibres (GNFs) have been synthesised by heat treatment of electrospun polyacrylonitrile in dimethylsulphoxide, offering a new solution route of low toxicity to manufacture sub-60 nm diameter GNFs. Fibre beading resulting from the spinning of low-concentration polymer solutions can be reduced with the addition of surfactant or sodium chloride. Characterisation techniques including X-ray diffraction, scanning- and transmission electron microscopy have been used to quanti...

  7. Electrospun fibers for the prevention of human immunodeficiency virus

    Science.gov (United States)

    Ball, Cameron

    HIV/AIDS education, testing, and treatment have thus far failed to cease the pandemic spread of the HIV virus. HIV prevention is hindered by a lack of protective options beyond the ABC approach of abstinence, being faithful, and using condoms. One approach to address this inadequacy is to develop antiviral products for vaginal or rectal application that provide receptive partner-initiated protection against viral infection during sex. Such products, termed anti-HIV microbicides, can especially empower young women to take control over their sexual health. This work explored a new approach to anti-HIV microbicides: electrospun fibers for the delivery of small-molecule antiretroviral drugs. Electrospun microbicides are nonwoven fabrics made from polymer-based nanofibers. The wide array of polymers available for electrospinning allowed for the incorporation and release of chemically diverse agents. Since electrospun fibers have an extremely high surface area to volume ratio, they serve as excellent delivery systems for rapid drug delivery of both hydrophilic and hydrophobic agents. The flexibility in the design of electrospun fibers afforded by coaxial electrospinning further enabled the formulation of sustained-release microbicides. To demonstrate the power of electrospinning to deliver drugs over multiple timescales, composite microbicide fabrics were created to provide both rapid and sustained drug release from a single device. This work has produced alternative microbicide formulations, while establishing methods for the thorough characterization of these systems and solutions for the needs of people at risk of HIV infection. By addressing problems in both HIV prevention and drug delivery, this work has expanded our capacity to engineer elegant solutions to complex and pressing global health challenges.

  8. Next Generation of Electrospun Textiles for Chemical and Biological Protection and Air Filtration

    Science.gov (United States)

    2009-09-01

    and pump -’ Taylor Cone High Voltage Power Supply Insulated Adjustable Stand Figure 1.10. Electrospinning experimental setup Electrospinning...0 --------- ----------% --- ’F 106’ \\ PTFE Microporous Membrane (Wind Barrier) /PAN Electrospun...Nonwoven Batting (thermal Insulation layer) 10’ 0 .2 .4 .6 .8 1.0 Relative Humidity Figure 1.11. Transport properties of electrospun materials. (a

  9. Fabrication and mechanical characterization of 3D electrospun scaffolds for tissue engineering

    International Nuclear Information System (INIS)

    Wright, L D; Young, R T; Andric, T; Freeman, J W

    2010-01-01

    Electrospinning is a polymer processing technique that produces fibrous structures comparable to the extracellular matrix of many tissues. Electrospinning, however, has been severely limited in its tissue engineering capabilities because this technique has produced few three-dimensional structures. Sintering of electrospun materials provides a method to fabricate unique architectures and allow much larger structures to be made. Electrospun mats were sintered into strips and cylinders, and their tensile and compressive mechanical properties were measured. In addition, electrospun materials with salt pores (salt embedded within the material and then leached out) were fabricated to improve porosity of the electrospun materials for tissue engineering scaffolds. Sintered electrospun poly(d,l-lactide) and poly(l-lactide) (PDLA/PLLA) materials have higher tensile mechanical properties (modulus: 72.3 MPa, yield: 960 kPa) compared to unsintered PLLA (modulus: 40.36 MPa, yield: 675.5 kPa). Electrospun PDLA/PLLA cylinders with and without salt-leached pores had compressive moduli of 6.69 and 26.86 MPa, respectively, and compressive yields of 1.36 and 0.56 MPa, respectively. Sintering of electrospun materials is a novel technique that improves electrospinning application in tissue engineering by increasing the size and types of electrospun structures that can be fabricated.

  10. Electrospun biocomposite nanofibrous patch for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Molamma P; Ramakrishna, Seeram [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Kai, Dan [NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore (Singapore); Ghasemi-Mobarakeh, Laleh, E-mail: nnimpp@nus.edu.s [Islamic Azad University, Najafabad Branch, Isfahan (Iran, Islamic Republic of)

    2011-10-15

    A bioengineered construct that matches the chemical, mechanical, biological properties and extracellular matrix morphology of native tissue could be suitable as a cardiac patch for supporting the heart after myocardial infarction. The potential of utilizing a composite nanofibrous scaffold of poly(dl-lactide-co-glycolide)/gelatin (PLGA/Gel) as a biomimetic cardiac patch is studied by culturing a population of cardiomyocyte containing cells on the electrospun scaffolds. The chemical characterization and mechanical properties of the electrospun PLGA and PLGA/Gel nanofibers were studied by Fourier transform infrared spectroscopy, scanning electron microscopy and tensile measurements. The biocompatibility of the scaffolds was also studied and the cardiomyocytes seeded on PLGA/Gel nanofibers were found to express the typical functional cardiac proteins such as alpha-actinin and troponin I, showing the easy integration of cardiomyocytes on PLGA/Gel scaffolds. Our studies strengthen the application of electrospun PLGA/Gel nanofibers as a bio-mechanical support for injured myocardium and as a potential substrate for induction of endogenous cardiomyocyte proliferation, ultimately reducing the cardiac dysfunction and improving cardiac remodeling.

  11. Electrospun Fibers of Cyclodextrins and Poly(cyclodextrins

    Directory of Open Access Journals (Sweden)

    Alejandro Costoya

    2017-02-01

    Full Text Available Cyclodextrins (CDs can endow electrospun fibers with outstanding performance characteristics that rely on their ability to form inclusion complexes. The inclusion complexes can be blended with electrospinnable polymers or used themselves as main components of electrospun nanofibers. In general, the presence of CDs promotes drug release in aqueous media, but they may also play other roles such as protection of the drug against adverse agents during and after electrospinning, and retention of volatile fragrances or therapeutic agents to be slowly released to the environment. Moreover, fibers prepared with empty CDs appear particularly suitable for affinity separation. The interest for CD-containing nanofibers is exponentially increasing as the scope of applications is widening. The aim of this review is to provide an overview of the state-of-the-art on CD-containing electrospun mats. The information has been classified into three main sections: (i fibers of mixtures of CDs and polymers, including polypseudorotaxanes and post-functionalization; (ii fibers of polymer-free CDs; and (iii fibers of CD-based polymers (namely, polycyclodextrins. Processing conditions and applications are analyzed, including possibilities of development of stimuli-responsive fibers.

  12. Facile modification of electrospun fibrous structures with antifouling zwitterionic hydrogels.

    Science.gov (United States)

    Xu, Tong; Yang, Jing; Zhang, Jiamin; Zhu, Yingnan; Li, Qingsi; Pan, Chao; Zhang, Lei

    2017-12-28

    Electrospinning technology can easily produce different shaped fibrous structures, making them highly valuable to various biomedical applications. However, surface contamination of biomolecules, cells, or blood has emerged as a significant challenge to the success of electrospun devices, especially artificial blood vessels, catheters and wound dressings etc. Many efforts have been made to resist the surface non-specific biomolecules or cells adsorption, but most of them require complex pre-treatment processes, hard-to-remove metal catalysts or rigorous reaction conditions. In addition, the stability of antifouling coatings, especially in complex conditions, is still a major concern. In this work, inspired by the interpenetrating polymer network and reinforced concrete structure, an efficient and facile strategy for modifying hydrophobic electrospun meshes and tubes with antifouling zwitterionic hydrogels has been introduced. The resulting products could efficiently resist the adhesion of proteins, cells, or even fresh whole blood. Meanwhile, they could maintain the shapes and mechanical strength of the original electrospun structures. Furthermore, the hydrogel structures could retain stable in a physiological condition for at least 3 months. This paper provided a general antifouling and hydrophilicity surface modification strategy for various fibrous structures, and could be of great value for many biomedical applications where antifouling properties are critical.

  13. ECM Decorated Electrospun Nanofiber for Improving Bone Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Yong Fu

    2018-03-01

    Full Text Available Optimization of nanofiber surface properties can lead to enhanced tissue regeneration outcomes in the context of bone tissue engineering. Herein, we developed a facile strategy to decorate elctrospun nanofibers using extracellular matrix (ECM in order to improve their performance for bone tissue engineering. Electrospun PLLA nanofibers (PLLA NF were seeded with MC3T3-E1 cells and allowed to grow for two weeks in order to harvest a layer of ECM on nanofiber surface. After decellularization, we found that ECM was successfully preserved on nanofiber surface while maintaining the nanostructure of electrospun fibers. ECM decorated on PLLA NF is biologically active, as evidenced by its ability to enhance mouse bone marrow stromal cells (mBMSCs adhesion, support cell proliferation and promote early stage osteogenic differentiation of mBMSCs. Compared to PLLA NF without ECM, mBMSCs grown on ECM/PLLA NF exhibited a healthier morphology, faster proliferation profile, and more robust osteogenic differentiation. Therefore, our study suggests that ECM decoration on electrospun nanofibers could serve as an efficient approach to improving their performance for bone tissue engineering.

  14. Incorporation of T4 bacteriophage in electrospun fibres.

    Science.gov (United States)

    Korehei, R; Kadla, J

    2013-05-01

    Antibacterial food packaging materials, such as bacteriophage-activated electrospun fibrous mats, may address concerns triggered by waves of bacterial food contamination. To address this, we investigated several efficient methods for incorporating T4 bacteriophage into electrospun fibrous mats. The incorporation of T4 bacteriophage using simple suspension electrospinning led to more than five orders of magnitude decrease in bacteriophage activity. To better maintain bacteriophage viability, emulsion electrospinning was developed where the T4 bacteriophage was pre-encapsulated in an alginate reservoir via an emulsification process and subsequently electrospun into fibres. This resulted in an increase in bacteriophage viability, but there was still two orders of magnitude drop in activity. Using a coaxial electrospinning process, full bacteriophage activity could be maintained. In this process, a core/shell fibre structure was formed with the T4 bacteriophage being directly incorporated into the fibre core. The core/shell fibre encapsulated bacteriophage exhibited full bacteriophage viability after storing for several weeks at +4°C. Coaxial electrospinning was shown to be capable of encapsulating bacteriophages with high loading capacity, high viability and long storage time. These results are significant in the context of controlling and preventing bacterial infections in perishable foods during storage. © 2013 The Society for Applied Microbiology.

  15. Transfer printing and patterning of stretchable electrospun film

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yongqing; Huang, YongAn, E-mail: yahuang@hust.edu.cn; Yin, Zhouping

    2013-10-01

    Electrospinning is an effective method for nanofiber production, but seldom used in the fabrication of patterned structures directly due to the whipping instability of the electrospinning jet. The whipping instability of electrospinning is adopted to fabricate stretchable patterned film by combination with an improved thermal transfer printing. The electrospun film is composed of small-scale wavy/coiled fibers, which make the patterned film highly stretchable. The optimal process parameters of whipping-based electrospinning are investigated to fabricate electrospun film with uniform and compact wavy/coiled fiber. Then the transfer printing and thermal detachment lithography are studied to generate patterned film, including the pressure, temperature, and peeling-off speed. Finally, the stretchability of the patterned electrospun film is studied through experiment and finite element analysis. It may open a cost-effective and high-throughput way for flexible/stretchable electronics fabrication. - Highlights: • Stretchable nonwoven film with small-scale wavy fibers is fabricated. • The film is transferred and patterned by thermal detachment lithography. • The patterned film is validated with high stretchability.

  16. Physical characterization of functionalized spider silk: electronic and sensing properties

    Directory of Open Access Journals (Sweden)

    Eden Steven, Jin Gyu Park, Anant Paravastu, Elsa Branco Lopes, James S Brooks, Ongi Englander, Theo Siegrist, Papatya Kaner and Rufina G Alamo

    2011-01-01

    Full Text Available This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline and amorphous (helical structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 °C, has a strong effect on the morphology of silk bundles (increasing their size, on the process of pyrolization (suppressing mass loss rates and on the resulting carbonized fiber structure (that becomes more robust against bending and strain. The effects of iodine doping and other functional parameters (vacuum and thin film coating motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and β-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR spectroscopy, revealing a partial transformation of β-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof

  17. Physical characterization of functionalized spider silk: electronic and sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Steven, Eden; Brooks, James S [Department of Physics and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, FL 32310 (United States); Park, Jin Gyu [FAMU-FSU Department of Industrial and Manufacturing Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Ave., Tallahassee, FL 32310 (United States); Paravastu, Anant; Siegrist, Theo; Kaner, Papatya; Alamo, Rufina G [FAMU-FSU Department of Chemical and Biomedical Engineering and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, FL 32310 (United States); Branco Lopes, Elsa [Departamento de Quimica, Instituto Tecnologico e Nuclear/CFMC-UL, P-2686-953 Sacavem (Portugal); Englander, Ongi, E-mail: esteven@magnet.fsu.edu [FAMU-FSU Department of Mechanical Engineering and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, Florida 32310 (United States)

    2011-10-15

    This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of {beta}-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 deg. C, has a strong effect on the morphology of silk bundles (increasing their size), on the process of pyrolization (suppressing mass loss rates) and on the resulting carbonized fiber structure (that becomes more robust against bending and strain). The effects of iodine doping and other functional parameters (vacuum and thin film coating) motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR) to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and {beta}-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR) spectroscopy, revealing a partial transformation of {beta}-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof

  18. Physical characterization of functionalized spider silk: electronic and sensing properties

    International Nuclear Information System (INIS)

    Steven, Eden; Brooks, James S; Park, Jin Gyu; Paravastu, Anant; Siegrist, Theo; Kaner, Papatya; Alamo, Rufina G; Branco Lopes, Elsa; Englander, Ongi

    2011-01-01

    This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 deg. C, has a strong effect on the morphology of silk bundles (increasing their size), on the process of pyrolization (suppressing mass loss rates) and on the resulting carbonized fiber structure (that becomes more robust against bending and strain). The effects of iodine doping and other functional parameters (vacuum and thin film coating) motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR) to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and β-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR) spectroscopy, revealing a partial transformation of β-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof-of-concept applications of

  19. Subchronic toxicity study of corn silk with rats.

    Science.gov (United States)

    Wang, Cuina; Zhang, Tiehua; Liu, Jun; Lu, Shuang; Zhang, Cheng; Wang, Erlei; Wang, Zuozhao; Zhang, Yan; Liu, Jingbo

    2011-09-01

    Corn silk is a traditional herbal medicine in China, which has been used in many parts of the world for the treatment of edema as well as for cystitis, gout, kidney stones, nephritis, prostatitis and similar ailments. However, there is little scientific evidence about its safety. As a part of its safety assessment, a subchronic toxicity was performed in this paper. The subchronic toxicity was investigated in male and female Wistar rats by dietary administration at concentrations of 0.5%, 2.0% and 8.0% (w/w) for 90 days. Overall health, body weight, food consumption, hematology, blood chemistry, organ weights, gross and microscopic appearance of tissues were compared between test and control groups. A number of significant differences were seen between groups, but none of them was considered to be adverse. Based on the present study, the no-observed-adverse-effect level (NOAEL) of corn silk is at least 8.0% which corresponds to a mean daily corn silk intake of approximately 9.354 and 10.308 g/day/kg body weight for males and females, respectively. The results obtained in the present study suggest that consumption of corn silk has no adverse effects and support the safety of corn silk for humans. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Adsorption Properties of Lac Dyes on Wool, Silk, and Nylon

    Directory of Open Access Journals (Sweden)

    Bo Wei

    2013-01-01

    Full Text Available There has been growing interest in the dyeing of textiles with natural dyes. The research about the adsorption properties of natural dyes can help to understand their adsorption mechanism and to control their dyeing process. This study is concerned with the kinetics and isotherms of adsorption of lac dyes on wool, silk, and nylon fibers. It was found that the adsorption kinetics of lac dyes on the three fibers followed the pseudosecond-order kinetic model, and the adsorption rate of lac dyes was the fastest for silk and the slowest for wool. The activation energies for the adsorption process on wool, silk, and nylon were found to be 107.15, 87.85, and 45.31 kJ/mol, respectively. The adsorption of lac dyes on the three fibers followed the Langmuir mechanism, indicating that the electrostatic interactions between lac dyes and those fibers occurred. The saturation values for lac adsorption on the three fibers decreased in the order of wool > silk > nylon; the Langmuir affinity constant of lac adsorption on nylon was much higher than those on wool and silk.

  1. Biomaterials Derived from Silk-Tropoelastin Protein Systems

    Science.gov (United States)

    Hu, Xiao; Wang, Xiuli; Rnjak, Jelena; Weiss, Anthony S.; Kaplan, David L.

    2010-01-01

    A structural protein blend system based on silkworm silk fibroin and recombinant human tropoelastin is described. Silk fibroin, a semicrystalline fibrous protein with beta-sheet crystals provides mechanical strength and controllable biodegradation, while tropoelastin, a noncrystallizable elastic protein provides elasticity. Differential scanning calorimetry (DSC) and temperature modulated DSC (TMDSC) indicated that silk becomes miscible with tropoelastin at different blend ratios, without macrophase separation. Fourier transform infrared spectroscopy (FTIR) revealed secondary structural changes of the blend system (beta-sheet content) before and after methanol treatment. Atomic Force Microscopy (AFM) nano-indentation demonstrated that blending silk and tropoelastin at different ratios resulted in modification of mechanical features, with resilience from ~68% to ~97%, and elastic modulus between 2~9Mpa, depending on the ratio of the two polymers. Some of these values are close to those of native aortic elastin or elastin-like polypeptides. Significantly, during blending and drying silk-tropoelastin form micro- and nano-scale porous morphologies which promote human mesenchymal stem cell attachment and proliferation. These blends offer a new protein biomaterial system for cell support and tailored biomaterial properties to match mechanical needs. PMID:20674969

  2. The Effects of Silk Protein Solution on Quality of Mangosteen

    International Nuclear Information System (INIS)

    Phadvibulya, Valailak; Sudatis, Boonya; Panyarum, Kanyarat; Junsaithong, Mayuree; Kerdchoechuen, Orapin

    2011-06-01

    Full text: Sericin silk protein solution prepared from irradiated silk waste was applied as a wax coating on mangosteen fruits but was found not appropriate. Nonetheless, when the solution was sprayed onto fruits from the setting stage till maturity, it enhanced the fruit quality. Fruits showed a bigger stalk and greener, thicker and larger-angled calyx than untreated ones. They were edible after being kept at 25 C for 3 to 4 weeks. Fruits sprayed with the silk protein solution and untreated fruits were separately harvested and packed for export. A half of them were irradiated with gamma radiation for insect eradication and then kept at 10 C with 80 percents relative humidity. The unirradiated half was stored similarly. Results showed that rind color of irradiated fruits changed slower than unirradiated ones. However, silk protein solution spraying and irradiation did not affect fruit firmness and total soluble solids of mangosteen flesh. For sensory evaluation, it was found that sprayed and irradiated fruits showed no differences from the untreated ones in their physical properties, color, taste and odor. Fruits sprayed with the silk protein solution without irradiation had the longest shelf life of 6 weeks

  3. Extracted sericin from silk waste for film formation

    Directory of Open Access Journals (Sweden)

    Rungsinee Sothornvit

    2010-03-01

    Full Text Available Sericin is the second main component in cocoons, which are removed in the silk reeling process of the raw silk industry and in the silk waste degumming of the spun silk industry. The main amino acid of sericin, serine, exhibits a skin moisturing and antiwrinkle action, which is interesting to use for film formation in this study. The extraction conditions of sericin from two silk wastes, pieced cocoon and inferior knubbs were studied to find the optimum extraction conditions. Boiling water extraction was considered based on the response surface methodology (RSM in order to identify the important factors for the sericin extraction. The two factors considered were time and temperature. Both factors were needed to be independent parameters in the predicted equation in order to improve the model fit with R2 = 0.84. The components ofextracted sericin were 18.24% serine, 9.83% aspatate, and 5.51% glycine with a molecular weight of 132 kDa. Film formationfrom extracted sericin was carried out to find the optimum conditions. Extracted sericin could not form a stand-alonefilm. Therefore, polysaccharide polymers, such as glucomannan, were incorporated with glycerol to form a flexible film.Sericin-based films were characterized for its properties in terms of solubility and permeability before application. It wasfound that sericin-based films showed a film flexibility and solubility without an increasing film water vapor permeability.

  4. The Effects of Silk Protein Solution on Quality of Mangosteen

    Energy Technology Data Exchange (ETDEWEB)

    Phadvibulya, Valailak; Sudatis, Boonya; Panyarum, Kanyarat; Junsaithong, Mayuree [Thailand Institute of Nuclear Technology, Nakhon Nayok, (Thailand); Kerdchoechuen, Orapin [School of Bioresources and Technology, King Mongkuts University, Bangkok (Thailand)

    2011-06-15

    Full text: Sericin silk protein solution prepared from irradiated silk waste was applied as a wax coating on mangosteen fruits but was found not appropriate. Nonetheless, when the solution was sprayed onto fruits from the setting stage till maturity, it enhanced the fruit quality. Fruits showed a bigger stalk and greener, thicker and larger-angled calyx than untreated ones. They were edible after being kept at 25{sup C} for 3 to 4 weeks. Fruits sprayed with the silk protein solution and untreated fruits were separately harvested and packed for export. A half of them were irradiated with gamma radiation for insect eradication and then kept at 10{sup C} with 80 percents relative humidity. The unirradiated half was stored similarly. Results showed that rind color of irradiated fruits changed slower than unirradiated ones. However, silk protein solution spraying and irradiation did not affect fruit firmness and total soluble solids of mangosteen flesh. For sensory evaluation, it was found that sprayed and irradiated fruits showed no differences from the untreated ones in their physical properties, color, taste and odor. Fruits sprayed with the silk protein solution without irradiation had the longest shelf life of 6 weeks.

  5. Engineering of Corneal Tissue through an Aligned PVA/Collagen Composite Nanofibrous Electrospun Scaffold.

    Science.gov (United States)

    Wu, Zhengjie; Kong, Bin; Liu, Rui; Sun, Wei; Mi, Shengli

    2018-02-24

    Corneal diseases are the main reason of vision loss globally. Constructing a corneal equivalent which has a similar strength and transparency with the native cornea, seems to be a feasible way to solve the shortage of donated cornea. Electrospun collagen scaffolds are often fabricated and used as a tissue-engineered cornea, but the main drawback of poor mechanical properties make it unable to meet the requirement for surgery suture, which limits its clinical applications to a large extent. Aligned polyvinyl acetate (PVA)/collagen (PVA-COL) scaffolds were electrospun by mixing collagen and PVA to reinforce the mechanical strength of the collagen electrospun scaffold. Human keratocytes (HKs) and human corneal epithelial cells (HCECs) inoculated on aligned and random PVA-COL electrospun scaffolds adhered and proliferated well, and the aligned nanofibers induced orderly HK growth, indicating that the designed PVA-COL composite nanofibrous electrospun scaffold is suitable for application in tissue-engineered cornea.

  6. Rapid nano impact printing of silk biopolymer thin films

    Science.gov (United States)

    White, Robert D.; Gray, Caprice; Mandelup, Ethan; Amsden, Jason J.; Kaplan, David L.; Omenetto, Fiorenzo G.

    2011-11-01

    In this paper, nano impact printing of silk biopolymer films is described. An indenter is rapidly accelerated and transfers the nanopattern from a silicon master into the silk film during an impact event that occurs in less than 1 ms. Contact stresses of greater than 100 MPa can be achieved during the short impact period with low power and inexpensive hardware. Ring shaped features with a diameter of 2 µm and a ring width of 100-200 nm were successfully transferred into untreated silk films using this method at room temperature. Mechanical modeling was carried out to determine the contact stress distribution, and demonstrates that imprinting can occur for contact stresses of less than 2 MPa. Thermal characterization at the impact location shows that raising the temperature to 70 °C has only a limited effect on pattern transfer. Contact stresses of greater than approximately 100 MPa result in excessive deformation of the film and poor pattern transfer.

  7. Rapid nano impact printing of silk biopolymer thin films

    International Nuclear Information System (INIS)

    White, Robert D; Gray, Caprice; Mandelup, Ethan; Amsden, Jason J; Kaplan, David L; Omenetto, Fiorenzo G

    2011-01-01

    In this paper, nano impact printing of silk biopolymer films is described. An indenter is rapidly accelerated and transfers the nanopattern from a silicon master into the silk film during an impact event that occurs in less than 1 ms. Contact stresses of greater than 100 MPa can be achieved during the short impact period with low power and inexpensive hardware. Ring shaped features with a diameter of 2 µm and a ring width of 100–200 nm were successfully transferred into untreated silk films using this method at room temperature. Mechanical modeling was carried out to determine the contact stress distribution, and demonstrates that imprinting can occur for contact stresses of less than 2 MPa. Thermal characterization at the impact location shows that raising the temperature to 70 °C has only a limited effect on pattern transfer. Contact stresses of greater than approximately 100 MPa result in excessive deformation of the film and poor pattern transfer.

  8. Beneficial Effects of Corn Silk on Metabolic Syndrome.

    Science.gov (United States)

    Wang, Bing; Xiao, Tiegang; Ruan, Jun; Liu, Wensheng

    2017-01-01

    Metabolic syndrome (MS) is a very common medical problem worldwide. It includes obesity, hypertension, hyperglycemia, and abnormal levels of triglycerides and high-density lipoprotein cholesterol. It is closely associated with insulin resistance and may lead to diabetes mellitus, liver diseases, or cardiovascular diseases. Corn silk (CS), a traditional Chinese medicine, has been reported to have multiple beneficial effects, including hypotensive, anti-diabetic, and hypolipidemic properties. This suggests that corn silk could be used to treat or prevent metabolic syndrome. In this review, we will discuss the potential role of corn silk in different components of metabolic syndrome. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. Fabrication and characterization of biomaterial film from gland silk of muga and eri silkworms.

    Science.gov (United States)

    Dutta, Saranga; Talukdar, Bijit; Bharali, Rupjyoti; Rajkhowa, Rangam; Devi, Dipali

    2013-05-01

    This study discusses the possibilities of liquid silk (Silk gland silk) of Muga and Eri silk, the indigenous non mulberry silkworms of North Eastern region of India, as potential biomaterials. Silk protein fibroin of Bombyx mori, commonly known as mulberry silkworm, has been extensively studied as a versatile biomaterial. As properties of different silk-based biomaterials vary significantly, it is important to characterize the non mulberry silkworms also in this aspect. Fibroin was extracted from the posterior silk gland of full grown fifth instars larvae, and 2D film was fabricated using standard methods. The films were characterized using SEM, Dynamic contact angle test, FTIR, XRD, DSC, and TGA and compared with respective silk fibers. SEM images of films reveal presence of some globules and filamentous structure. Films of both the silkworms were found to be amorphous with random coil conformation, hydrophobic in nature, and resistant to organic solvents. Non mulberry silk films had higher thermal resistance than mulberry silk. Fibers were thermally more stable than the films. This study provides insight into the new arena of research in application of liquid silk of non mulberry silkworms as biomaterials. Copyright © 2012 Wiley Periodicals, Inc.

  10. Improved human tenocyte proliferation and differentiation in vitro by optimized silk degumming

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiao; Qiu Yiwei; Carr, Andrew J; Triffitt, James T; Sabokbar, Afsie; Xia Zhidao, E-mail: z.xia@swansea.ac.uk [Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford (United Kingdom)

    2011-06-15

    Tendon disorders are common clinical conditions. Tendon tissue engineering provides a new approach for tendon repair by integrating engineered substitutes with their native counterparts. Silk is considered to be a promising candidate for tendon engineering because of its biological and mechanical properties. However, a major concern with using silk for biomedical applications is the immune responses generated by sericin, a glue-like protein that coats the silk fibres. This study improves the existing protocols for silk 'degumming' which removes sericin and enables preparation of silk that is suitable for tendon regeneration. Bombyx mori silks were treated by sequential treatments with different proteases. The efficiency of degumming was determined by measuring weight loss, picric acid and carmine staining and scanning electron microscopy. To evaluate the cellular responses after degumming, the growth and differentiation of human tenocytes on silks were examined. The results showed that sequential protease treatment effectively degummed raw silks. The sequentially degummed silks showed enhanced tenocyte proliferation and upregulated mRNA levels of tendon markers. Thick cell multilayers formed on the treated silks, with cells and collagen fibres penetrating into the spaces in individual silk filaments, resulting in a structure resembling human tendon.

  11. Improved human tenocyte proliferation and differentiation in vitro by optimized silk degumming

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Wang; Yiwei, Qiu; Carr, Andrew J; Triffitt, James T; Sabokbar, Afsie; Xia Zhidao, E-mail: z.xia@swansea.ac.uk [Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford (United Kingdom)

    2011-06-15

    Tendon disorders are common clinical conditions. Tendon tissue engineering provides a new approach for tendon repair by integrating engineered substitutes with their native counterparts. Silk is considered to be a promising candidate for tendon engineering because of its biological and mechanical properties. However, a major concern with using silk for biomedical applications is the immune responses generated by sericin, a glue-like protein that coats the silk fibres. This study improves the existing protocols for silk 'degumming' which removes sericin and enables preparation of silk that is suitable for tendon regeneration. Bombyx mori silks were treated by sequential treatments with different proteases. The efficiency of degumming was determined by measuring weight loss, picric acid and carmine staining and scanning electron microscopy. To evaluate the cellular responses after degumming, the growth and differentiation of human tenocytes on silks were examined. The results showed that sequential protease treatment effectively degummed raw silks. The sequentially degummed silks showed enhanced tenocyte proliferation and upregulated mRNA levels of tendon markers. Thick cell multilayers formed on the treated silks, with cells and collagen fibres penetrating into the spaces in individual silk filaments, resulting in a structure resembling human tendon.

  12. The osteogenic potential of mesoporous bioglasses/silk and non-mesoporous bioglasses/silk scaffolds in ovariectomized rats: in vitro and in vivo evaluation.

    Directory of Open Access Journals (Sweden)

    Ning Cheng

    Full Text Available Silk-based scaffolds have been introduced to bone tissue regeneration for years, however, their local therapeutic efficiency in bone metabolic disease condition has been seldom reported. According to our previous report, mesoporous bioactive glass (MBG/silk scaffolds exhibits superior in vitro bioactivity and in vivo osteogenic properties compared to non-mesoporous bioactive glass (BG/silk scaffolds, but no information could be found about their efficiency in osteoporotic (OVX environment. This study investigated a biomaterial-based approach for improving MSCs behavior in vitro, and accelerating OVX defect healing by using 3D BG/silk and MBG/silk scaffolds, and pure silk scaffolds as control. The results of SEM, CCK-8 assay and quantitative ALP activity showed that MBG/silk scaffolds can improve attachment, proliferation and osteogenic differentiation of both O-MSCs and sham control. In vivo therapeutic efficiency was evaluated by μCT analysis, hematoxylin and eosin staining, safranin O staining and tartrate-resistant acid phosphatase, indicating accelerated bone formation with compatible scaffold degradation and reduced osteoclastic response of defect healing in OVX rats after 2 and 4 weeks treatment, with a rank order of MBG/silk > BG/silk > silk group. Immunohistochemical markers of COL I, OPN, BSP and OCN also revealed that MBG/silk scaffolds can better induce accelerated collagen and non-collagen matrix production. The findings of this study suggest that MBG/silk scaffolds provide a better environment for cell attachment, proliferation and differentiation, and act as potential substitute for treating local osteoporotic defects.

  13. Quantitative analysis of allantoin in Iranian corn silk

    Directory of Open Access Journals (Sweden)

    E. Khanpour*

    2017-11-01

    Full Text Available Background and objectives: Zea mays is cultivated in different parts of Iran and corn silk is used in traditional medicine. Allantoin is one of the major compounds in corn silk. The purpose of this research was the quantitatve analysis of allantoin in corn silks belonging to several regions of Iran. Methods: The samples of corn silk were prepared from three provinces of Iran (Kermanshah, Fars and Razavi Khorasan. The dried plant materials were infused in boiling distilled water with a temperature of 90-95 °C on magnetic stirrer for 30 min. The levels of allantoin in aqueous extracts were determined by HPLC. Quantification was achieved using an C18 column (250×4.6 mm, 5 µm under isocratic conditions and phosphate buffer solution (pH 3.0 as the mobile phase at a flow rate of 0.5 mL/min. Column effluent was monitored at 210 nm. The calibration curve of allantoin standard was plotted with concentrations from 6.25 to 100 µg/mL. Results: The calibration curve of standard was linear over the concentration range used (R2=0.9999. The results showed that the amount of allantoin in samples was between 205 and 374 mg/100g of dry plant material. The corn silk samples of Razavi Khorasan and Fars provinces showed the lowest and highest amount of allantoin, respectively. Conclusion: The levels of allantoin obtained in this study were higher than the values reported in other studies; therefore, the researchers of this project are investigating the wound healing effect of corn silk.

  14. Design and Optimization of Resorbable Silk Internal Fixation Devices

    Science.gov (United States)

    Haas, Dylan S.

    Limitations of current material options for internal fracture fixation devices have resulted in a large gap between user needs and hardware function. Metal systems offer robust mechanical strength and ease of implantation but require secondary surgery for removal and/or result in long-term complications (infection, palpability, sensitivity, etc.). Current resorbable devices eliminate the need for second surgery and long-term complications but are still associated with negative host response as well as limited functionality and more difficult implantation. There is a definitive need for orthopedic hardware that is mechanically capable of immediate fracture stabilization and fracture fixation during healing, can safely biodegrade while allowing complete bone remodeling, can be resterilized for reuse, and is easily implantable (self-tapping). Previous work investigated the use of silk protein to produce resorbable orthopedic hardware for non- load bearing fracture fixation. In this study, silk orthopedic hardware was further investigated and optimized in order to better understand the ability of silk as a fracture fixation system and more closely meet the unfulfilled market needs. Solvent-based and aqueous-based silk processing formulations were cross-linked with methanol to induce beta sheet structure, dried, autoclaved and then machined to the desired device/geometry. Silk hardware was evaluated for dry, hydrated and fatigued (cyclic) mechanical properties, in vitro degradation, resterilization, functionalization with osteoinductive molecules and implantation technique for fracture fixation. Mechanical strength showed minor improvements from previous results, but remains comparable to current resorbable fixation systems with the advantages of self-tapping ability for ease of implantation, full degradation in 10 months, ability to be resterilized and reused, and ability to release molecules for osteoinudction. In vivo assessment confirmed biocompatibility, showed

  15. Silk-Quality, Spinnability and Low Temperature Behavior

    Science.gov (United States)

    2015-12-02

    inert  atmosphere  (N2   gas   flow  rate  of  100  mL/min).  Changes   in  weight  percentage  during   temperature...Performance 3. DATES COVERED (From - To) 01-06-2012 to 31-05-2015 4. TITLE AND SUBTITLE Silk-Quality, Spinnability and Low Temperature Behaviour 5a...deploy the huge range in mechanical behaviour between different silk species and intra-species varieties. In particular, I set out to formulate a

  16. Corn silk induced cyclooxygenase-2 in murine macrophages.

    Science.gov (United States)

    Kim, Kyung A; Shin, Hyun-Hee; Choi, Sang Kyu; Choi, Hye-Seon

    2005-10-01

    Stimulation of murine macrophages with corn silk induced cyclooxygenase (COX)-2 with secretion of PGE2. Expression of COX-2 was inhibited by pyrolidine dithiocarbamate (PDTC), and increased DNA binding by nuclear factor kappa B (NF-kappaB), indicating that COX-2 induction proceeds also via the NF-kappaB signaling pathway. A specific inhibitor of COX-2 decreased the expression level of inducible nitric oxide synthase (iNOS) stimulated by corn silk. PGE2 elevated the expression level of iNOS, probably via EP2 and EP4 receptors on the surface of the macrophages.

  17. Untangling spider silk evolution with spidroin terminal domains

    Directory of Open Access Journals (Sweden)

    Garb Jessica E

    2010-08-01

    Full Text Available Abstract Background Spidroins are a unique family of large, structural proteins that make up the bulk of spider silk fibers. Due to the highly variable nature of their repetitive sequences, spidroin evolutionary relationships have principally been determined from their non-repetitive carboxy (C-terminal domains, though they offer limited character data. The few known spidroin amino (N-terminal domains have been difficult to obtain, but potentially contain critical phylogenetic information for reconstructing the diversification of spider silks. Here we used silk gland expression data (ESTs from highly divergent species to evaluate the functional significance and phylogenetic utility of spidroin N-terminal domains. Results We report 11 additional spidroin N-termini found by sequencing ~1,900 silk gland cDNAs from nine spider species that shared a common ancestor > 240 million years ago. In contrast to their hyper-variable repetitive regions, spidroin N-terminal domains have retained striking similarities in sequence identity, predicted secondary structure, and hydrophobicity. Through separate and combined phylogenetic analyses of N-terminal domains and their corresponding C-termini, we find that combined analysis produces the most resolved trees and that N-termini contribute more support and less conflict than the C-termini. These analyses show that paralogs largely group by silk gland type, except for the major ampullate spidroins. Moreover, spidroin structural motifs associated with superior tensile strength arose early in the history of this gene family, whereas a motif conferring greater extensibility convergently evolved in two distantly related paralogs. Conclusions A non-repetitive N-terminal domain appears to be a universal attribute of spidroin proteins, likely retained from the origin of spider silk production. Since this time, spidroin N-termini have maintained several features, consistent with this domain playing a key role in silk

  18. Structure determination of spider silk from X-ray images

    Energy Technology Data Exchange (ETDEWEB)

    Ulrich, Stephan; Zippelius, Annette [Universitaet Goettingen, Institut fuer Theoretische Physik (Germany); Meling, Martin [Max-Planck-Institut fuer biophysikalische Chemie, Goettingen (Germany); Glisovic, Anja; Salditt, Tim [Universitaet Goettingen, Institut fuer Roentgenphysik (Germany)

    2008-07-01

    Spider silk consists of interconnected crystallites, which are typically aligned along the fiber axis. We present a method to systematically determine the structure of these crystallites. Hereby we introduce a model that calculates the scattering function G(q) which is fitted to the measured X-ray image (silk from nephila clavipes). With it, the crystallites' size, the constitution and dimensions of their unit cell, as well as their tilt with respect to the fiber axis is identified, and furthermore the effect of coherent scattering from different crystallites is investigated. The shown methods and the presented model can easily be generalized to a wide class of composite materials.

  19. Nano/micro hybrid scaffold of PCL or P3HB nanofibers combined with silk fibroin for tendon and ligament tissue engineering.

    Science.gov (United States)

    Naghashzargar, Elham; Farè, Silvia; Catto, Valentina; Bertoldi, Serena; Semnani, Dariush; Karbasi, Saeed; Tanzi, Maria Cristina

    2015-07-04

    A novel biodegradable nano/micro hybrid structure was obtained by electrospinning P3HB or PCL nanofibers onto a twisted silk fibroin (SF) structure, with the aim of fabricating a suitable scaffold for tendon and ligament tissue engineering. The electrospinning (ES) processing parameters for P3HB and PCL were optimized on 2D samples, and applied to produce two different nano/micro hybrid constructs (SF/ES-PCL and SF/ES-P3HB).Morphological, chemico-physical and mechanical properties of the novel hybrid scaffolds were evaluated by SEM, ATR FT-IR, DSC, tensile and thermodynamic mechanical tests. The results demonstrated that the nanofibers were tightly wrapped around the silk filaments, and the crystallinity of the SF twisted yarns was not influenced by the presence of the electrospun polymers. The slightly higher mechanical properties of the hybrid constructs confirmed an increase of internal forces due to the interaction between nano and micro components. Cell culture tests with L929 fibroblasts, in the presence of the sample eluates or in direct contact with the hybrid structures, showed no cytotoxic effects and a good level of cytocompatibility of the nano/micro hybrid structures in term of cell viability, particularly at day 1. Cell viability onto the nano/micro hybrid structures decreased from the first to the third day of culture when compared with the control culture plastic, but appeared to be higher when compared with the uncoated SF yarns. Although additional in vitro and in vivo tests are needed, the original fabrication method here described appears promising for scaffolds suitable for tendon and ligament tissue engineering.

  20. Blood-Vessel Mimicking Structures by Stereolithographic Fabrication of Small Porous Tubes Using Cytocompatible Polyacrylate Elastomers, Biofunctionalization and Endothelialization

    Directory of Open Access Journals (Sweden)

    Birgit Huber

    2016-04-01

    Full Text Available Blood vessel reconstruction is still an elusive goal for the development of in vitro models as well as artificial vascular grafts. In this study, we used a novel photo-curable cytocompatible polyacrylate material (PA for freeform generation of synthetic vessels. We applied stereolithography for the fabrication of arbitrary 3D tubular structures with total dimensions in the centimeter range, 300 µm wall thickness, inner diameters of 1 to 2 mm and defined pores with a constant diameter of approximately 100 µm or 200 µm. We established a rinsing protocol to remove remaining cytotoxic substances from the photo-cured PA and applied thio-modified heparin and RGDC-peptides to functionalize the PA surface for enhanced endothelial cell adhesion. A rotating seeding procedure was introduced to ensure homogenous endothelial monolayer formation at the inner luminal tube wall. We showed that endothelial cells stayed viable and adherent and aligned along the medium flow under fluid-flow conditions comparable to native capillaries. The combined technology approach comprising of freeform additive manufacturing (AM, biomimetic design, cytocompatible materials which are applicable to AM, and biofunctionalization of AM constructs has been introduced as BioRap® technology by the authors.

  1. pH dependent interaction of biofunctionalized CdS nanoparticles with nucleobases and nucleotides: A fluorimetric study

    International Nuclear Information System (INIS)

    Chatterjee, Anindita; Priyam, Amiya; Bhattacharya, Subhash C.; Saha, Abhijit

    2007-01-01

    The interaction of DNA bases and corresponding nucleotides with CdS nanoparticles (NPs), biofunctionalized by cysteine, has been investigated by absorption and fluorescence spectroscopy. Unique enhancement effect of adenine, in contrast to other nucleobases, on the luminescence of cysteine capped CdS (cys-CdS) NPs at both pH 7.5 and 10.5 was found, the extent of enhancement being much higher at pH 10.5. At the latter pH, the difference optical absorption spectra show development of new peak at 278 nm with corresponding decrease in the absorption of adenine at 260 nm, which is attributed to binding of adenine anion to the CdS surface through N7 of the purine ring. Appearance of a new band at 478 cm -1 and concomitant shift in the C 8 -N 7 vibrations to 1610 cm -1 in the FTIR spectra of cys-CdS NPs with adenine also suggest Cd-N7 binding on the particle surface. Amongst various nucleotides, ATP exhibited maximum luminescence enhancement on CdS NPs for a given change in concentration in the micro-molar range at physiological pH. A quantitative correlation between ATP concentration and PL enhancement of CdS NPs has been established, a step which in future might assist in developing new protocols for fluorescence sensing of adenine nucleotides under certain pathological conditions

  2. A comparative study of in-flow and micro-patterning biofunctionalization protocols for nanophotonic silicon-based biosensors.

    Science.gov (United States)

    González-Guerrero, Ana Belén; Alvarez, Mar; García Castaño, Andrés; Domínguez, Carlos; Lechuga, Laura M

    2013-03-01

    Reliable immobilization of bioreceptors over any sensor surface is the most crucial step for achieving high performance, selective and sensitive biosensor devices able to analyze human samples without the need of previous processing. With this aim, we have implemented an optimized scheme to covalently biofunctionalize the sensor area of a novel nanophotonic interferometric biosensor. The proposed method is based on the ex-situ silanization of the silicon nitride transducer surface by the use of a carboxyl water soluble silane, the carboxyethylsilanetriol sodium salt (CTES). The use of an organosilane stable in water entails advantages in comparison with usual trialkoxysilanes such as avoiding the generation of organic waste and leading to the assembly of compact monolayers due to the high dielectric constant of water. Additionally, cross-linking is prevented when the conditions (e.g. immersion time, concentration of silane) are optimized. This covalent strategy is followed by the bioreceptor linkage on the sensor area surface using two different approaches: an in-flow patterning and a microcontact printing using a biodeposition system. The performance of the different bioreceptor layers assembled is compared by the real-time and label-free immunosensing of the proteins BSA/mAb BSA, employed as a model molecular pair. Although the results demonstrated that both strategies provide the biosensor with a stable biological interface, the performance of the bioreceptor layer assembled by microcontact printing slightly improves the biosensing capabilities of the photonic biosensor. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Bio-functionalization of polycaprolactone infiltrated BCP scaffold with silicon and fibronectin enhances osteoblast activity in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Kyung-A.; Kim, Young-Hee [Department of Microbiology and Immunology, School of Medicine, Soonchunhyang University, Cheonan, Chungnum 330-090 (Korea, Republic of); Kim, Minsung; Lee, Byong-Taek [Department of Biomedical Engineering and Materials, School of Medicine, Soonchunhyang University, Cheonan, Chungnum 330-090 (Korea, Republic of); Song, Ho-Yeon, E-mail: songmic@sch.ac.kr [Department of Microbiology and Immunology, School of Medicine, Soonchunhyang University, Cheonan, Chungnum 330-090 (Korea, Republic of)

    2013-08-15

    The surface property of a biomaterial plays a fundamental role in cell attachment, proliferation, differentiation, resorption, and biomolecular expression. In this study, the surface of a polycaprolactone-infiltrated biphasic calcium phosphate scaffold was biofunctionalized by silicon (Si) and fibronectin (FN) coating to evaluate the osteoblast-like cells activity in vitro. The surfaces of all scaffolds were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), whereas the presence of the functional group was determined by Fourier-transform infrared spectroscopy (FT-IR). Coomassie brilliant blue staining was applied to confirm the presence of FN on the scaffold surface. The in vitro bioactivity of the osteoblast-like cells was determined by one cell morphology and proliferation assay at 3, 7, and 14 days by SEM. Cell viability assay by MTT showed higher cell viability rate on coated scaffolds than in those coated with Si only or non-coated surfaces. The mRNA expressions of alkaline phosphatase (ALP) and osteocalcin (OC) were determined using RT-PCR and the expressions of osteopontin (OPN), type I collagen, and osteocalcin (OC) proteins were determined using Western blot. Thus the expression of genes and proteins further confirmed both early and intermediate phases of osteoblast-like cell activity which was found increased by Si-and Fn coating on PCL infiltrated BCP surfaces.

  4. Structure to function: Spider silk and human collagen

    Science.gov (United States)

    Rabotyagova, Olena S.

    Nature has the ability to assemble a variety of simple molecules into complex functional structures with diverse properties. Collagens, silks and muscles fibers are some examples of fibrous proteins with self-assembling properties. One of the great challenges facing Science is to mimic these designs in Nature to find a way to construct molecules that are capable of organizing into functional supra-structures by self-assembly. In order to do so, a construction kit consisting of molecular building blocks along with a complete understanding on how to form functional materials is required. In this current research, the focus is on spider silk and collagen as fibrous protein-based biopolymers that can shed light on how to generate nanostructures through the complex process of self-assembly. Spider silk in fiber form offers a unique combination of high elasticity, toughness, and mechanical strength, along with biological compatibility and biodegrability. Spider silk is an example of a natural block copolymer, in which hydrophobic and hydrophilic blocks are linked together generating polymers that organize into functional materials with extraordinary properties. Since silks resemble synthetic block copolymer systems, we adopted the principles of block copolymer design from the synthetic polymer literature to build block copolymers based on spider silk sequences. Moreover, we consider spider silk to be an important model with which to study the relationships between structure and properties in our system. Thus, the first part of this work was dedicated to a novel family of spider silk block copolymers, where we generated a new family of functional spider silk-like block copolymers through recombinant DNA technology. To provide fundamental insight into relationships between peptide primary sequence, block composition, and block length and observed morphological and structural features, we used these bioengineered spider silk block copolymers to study secondary structure

  5. Functional electrospun fibers for the treatment of human skin wounds.

    Science.gov (United States)

    Wang, Jing; Windbergs, Maike

    2017-10-01

    Wounds are trauma induced defects of the human skin involving a multitude of endogenous biochemical events and cellular reactions of the immune system. The healing process is extremely complex and affected by the patient's physiological conditions, potential implications like infectious pathogens and inflammation as well as external factors. Due to increasing incidence of chronic wounds and proceeding resistance of infection pathogens, there is a strong need for effective therapeutic wound care. In this context, electrospun fibers with diameters in the nano- to micrometer range gain increasing interest. While resembling the structure of the native human extracellular matrix, such fiber mats provide physical and mechanical protection (including protection against bacterial invasion). At the same time, the fibers allow for gas exchange and prevent occlusion of the wound bed, thus facilitating wound healing. In addition, drugs can be incorporated within such fiber mats and their release can be adjusted by the material and dimensions of the individual fibers. The review gives a comprehensive overview about the current state of electrospun fibers for therapeutic application on skin wounds. Different materials as well as fabrication techniques are introduced including approaches for incorporation of drugs into or drug attachment onto the fiber surface. Against the background of wound pathophysiology and established therapy approaches, the therapeutic potential of electrospun fiber systems is discussed. A specific focus is set on interactions of fibers with skin cells/tissues as well as wound pathogens and strategies to modify and control them as key aspects for developing effective wound therapeutics. Further, advantages and limitations of controlled drug delivery from fiber mats to skin wounds are discussed and a future perspective is provided. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Bioprospecting finds the toughest biological material: extraordinary silk from a giant riverine orb spider.

    Directory of Open Access Journals (Sweden)

    Ingi Agnarsson

    Full Text Available BACKGROUND: Combining high strength and elasticity, spider silks are exceptionally tough, i.e., able to absorb massive kinetic energy before breaking. Spider silk is therefore a model polymer for development of high performance biomimetic fibers. There are over 41,000 described species of spiders, most spinning multiple types of silk. Thus we have available some 200,000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila or simply from researchers' backyards. Are we limited to 'blindly fishing' in efforts to discover extraordinary silks? Or, could scientists use ecology to predict which species are likely to spin silks exhibiting exceptional performance properties? METHODOLOGY: We examined the biomechanical properties of silk produced by the remarkable Malagasy 'Darwin's bark spider' (Caerostris darwini, which we predicted would produce exceptional silk based upon its amazing web. The spider constructs its giant orb web (up to 2.8 m(2 suspended above streams, rivers, and lakes. It attaches the web to substrates on each riverbank by anchor threads as long as 25 meters. Dragline silk from both Caerostris webs and forcibly pulled silk, exhibits an extraordinary combination of high tensile strength and elasticity previously unknown for spider silk. The toughness of forcibly silked fibers averages 350 MJ/m(3, with some samples reaching 520 MJ/m(3. Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®. Caerostris capture spiral silk is similarly exceptionally tough. CONCLUSIONS: Caerostris darwini produces the toughest known biomaterial. We hypothesize that this extraordinary toughness coevolved with the unusual ecology and web architecture of these spiders, decreasing the likelihood of bridgelines breaking and collapsing the web

  7. Nanoclay-Directed Structure and Morphology in PVDF Electrospun Membranes

    Directory of Open Access Journals (Sweden)

    Kyunghwan Yoon

    2014-01-01

    Full Text Available The incorporation of organically modified Lucentite nanoclay dramatically modifies the structure and morphology of the PVDF electrospun fibers. In a molecular level, the nanoclay preferentially stabilizes the all-trans conformation of the polymer chain, promoting an α to β transformation of the crystalline phase. The piezoelectric properties of the β-phase carry great promise for energy harvest applications. At a larger scale, the nanoclay facilitates the formation of highly uniform, bead-free fibers. Such an effect can be attributed to the enhanced conductivity and viscoelasticity of the PVDF-clay suspension. The homogenous distribution of the directionally aligned nanoclays imparts advanced mechanical properties to the nanofibers.

  8. Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

    Science.gov (United States)

    Kohlman, Lee W.; Bakis, Charles; Williams, Tiffany S.; Johnston, James C.; Kuczmarski, Maria A.; Roberts, Gary D.

    2014-01-01

    Composite materials offer significant weight savings in many aerospace applications. The toughness of the interface of fibers crossing at different angles often determines failure of composite components. A method for toughening the interface in fabric and filament wound components using directly electrospun thermoplastic nanofiber on carbon fiber tow is presented. The method was first demonstrated with limited trials, and then was scaled up to a continuous lab scale process. Filament wound tubes were fabricated and tested using unmodified baseline towpreg material and nanofiber coated towpreg.

  9. Response of human corneal fibroblasts on silk film surface patterns.

    Science.gov (United States)

    Gil, Eun Seok; Park, Sang-Hyug; Marchant, Jeff; Omenetto, Fiorenzo; Kaplan, David L

    2010-06-11

    Transparent, biodegradable, mechanically robust, and surface-patterned silk films were evaluated for the effect of surface morphology on human corneal fibroblast (hCF) cell proliferation, orientation, and ECM deposition and alignment. A series of dimensionally different surface groove patterns were prepared from optically graded glass substrates followed by casting poly(dimethylsiloxane) (PDMS) replica molds. The features on the patterned silk films showed an array of asymmetric triangles and displayed 37-342 nm depths and 445-3 582 nm widths. hCF DNA content on all patterned films were not significantly different from that on flat silk films after 4 d in culture. However, the depth and width of the grooves influenced cell alignment, while the depth differences affected cell orientation; overall, deeper and narrower grooves induced more hCF orientation. Over 14 d in culture, cell layers and actin filament organization demonstrated that confluent hCFs and their cytoskeletal filaments were oriented along the direction of the silk film patterned groove axis. Collagen type V and proteoglycans (decorin and biglycan), important markers of corneal stromal tissue, were highly expressed with alignment. Understanding corneal stromal fibroblast responses to surface features on a protein-based biomaterial applicable in vivo for corneal repair potential suggests options to improve corneal tissue mimics. Further, the approaches provide fundamental biomaterial designs useful for bioengineering oriented tissue layers, an endemic feature in most biological tissue structures that lead to critical tissue functions.

  10. Visual responses of corn silk flies (Diptera: Ulidiidae)

    Science.gov (United States)

    Corn silk flies are major pests impacting fresh market sweet corn production in Florida and Georgia. Control depends solely on well-times applications of insecticides to protect corn ear development. Surveillance depends on visual inspection of ears with no effective trapping methods currently ava...

  11. Antibiotic-Releasing Silk Biomaterials for Infection Prevention and Treatment

    OpenAIRE

    Pritchard, Eleanor M.; Valentin, Thomas; Panilaitis, Bruce; Omenetto, Fiorenzo; Kaplan, David L.

    2012-01-01

    Effective treatment of infections in avascular and necrotic tissues can be challenging due to limited penetration into the target tissue and systemic toxicities. Controlled release polymer implants have the potential to achieve the high local concentrations needed while also minimizing systemic exposure. Silk biomaterials possess unique characteristics for antibiotic delivery including biocompatibility, tunable biodegradation, stabilizing effects, water-based processing and diverse material f...

  12. Differential scanning fluorimetry illuminates silk feedstock stability and processability

    Czech Academy of Sciences Publication Activity Database

    Dicko, C.; Kasoju, Naresh; Hawkins, N.; Vollrath, F.

    2016-01-01

    Roč. 12, č. 1 (2016), s. 255-262 ISSN 1744-683X R&D Projects: GA MŠk(CZ) EE2.3.30.0029 Institutional support: RVO:61389013 Keywords : differential scanning fluorimetry * biomaterials * silk fibroin Subject RIV: CE - Biochemistry Impact factor: 3.889, year: 2016

  13. Silk cocoon drying in forced convection type solar dryer

    International Nuclear Information System (INIS)

    Singh, Panna Lal

    2011-01-01

    The thin layer silk cocoon drying was studied in a forced convection type solar dryer. The drying chamber was provided with several trays on which the cocoons loaded in thin layer. The hot air generated in the solar air heater was forced into drying chamber to avoid the direct exposure of sunlight and UV radiation on cocoons. The drying air temperature varied from 50 to 75 o C. The cocoon was dried from the initial moisture content of about 60-12% (wb). The drying data was fitted to thin layer drying models. Drying behaviour of the silk cocoon was best fitted with the Wang and Singh drying model. Good agreement was obtained between predicted and experimental values. Quality of the cocoons dried in the solar dryer was at par with the cocoons dried in the conventional electrical oven dryer in term of the silk yield and strength of the silk. Saving of electrical energy was about 0.75 kWh/kg cocoons dried. Economic analysis indicated that the NPV of the solar dryer was higher and more stable (against escalation rate of electricity) as compare to the same for electrical oven dryer. Due to simplicity in design and construction and significant saving of operational electrical energy, solar cocoon dryer seems to be a viable option.

  14. The Political Economics of the New Silk Road

    Directory of Open Access Journals (Sweden)

    Sárvári Balázs

    2016-02-01

    Full Text Available What has now been coined the term XXI Century Silk Road had evolved from a speech given by Chinese premier Xi Jinping in Kazakhstan in 2013. It was initially a plan aimed at promoting the bilateral relations of China and its neighbors; however, the initiative had since then traversed the region’s borders and become a global project.

  15. Silk for silver : Dutch-Vietnamese relations, 1637-1700

    NARCIS (Netherlands)

    Hoang Anh Tuan,

    2006-01-01

    Against the background of a regional crisis caused by dynastic change in China and the closure of Japan in the middle of the seventeenth century, the Vietnamese kingdom of Tonkin rose to the fore as the major silk producing and exporting region in East Asia. Based on a wealth of so far unused

  16. Silk fibroin as biomaterial for bone tissue engineering.

    Science.gov (United States)

    Melke, Johanna; Midha, Swati; Ghosh, Sourabh; Ito, Keita; Hofmann, Sandra

    2016-02-01

    Silk fibroin (SF) is a fibrous protein which is produced mainly by silkworms and spiders. Its unique mechanical properties, tunable biodegradation rate and the ability to support the differentiation of mesenchymal stem cells along the osteogenic lineage, have made SF a favorable scaffold material for bone tissue engineering. SF can be processed into various scaffold forms, combined synergistically with other biomaterials to form composites and chemically modified, which provides an impressive toolbox and allows SF scaffolds to be tailored to specific applications. This review discusses and summarizes recent advancements in processing SF, focusing on different fabrication and functionalization methods and their application to grow bone tissue in vitro and in vivo. Potential areas for future research, current challenges, uncertainties and gaps in knowledge are highlighted. Silk fibroin is a natural biomaterial with remarkable biomedical and mechanical properties which make it favorable for a broad range of bone tissue engineering applications. It can be processed into different scaffold forms, combined synergistically with other biomaterials to form composites and chemically modified which provides a unique toolbox and allows silk fibroin scaffolds to be tailored to specific applications. This review discusses and summarizes recent advancements in processing silk fibroin, focusing on different fabrication and functionalization methods and their application to grow bone tissue in vitro and in vivo. Potential areas for future research, current challenges, uncertainties and gaps in knowledge are highlighted. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  17. Redoable Tie-Over Dressing Using Multiple Loop Silk Threads

    Directory of Open Access Journals (Sweden)

    Hyeon Jong Jo

    2013-05-01

    Full Text Available After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tie-over dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.

  18. Redoable Tie-Over Dressing Using Multiple Loop Silk Threads

    Directory of Open Access Journals (Sweden)

    Hyeon Jong Jo

    2013-05-01

    Full Text Available After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tieover dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.

  19. Silk fibroin as an organic polymer for controlled drug delivery

    NARCIS (Netherlands)

    Hofmann, S.; Foo, S.; Rossetti, F.; Textor, M.; Vunjak-Novakovic, G.; Kaplan, D.L.; Merkle, H.P.; Meinel, L.

    2006-01-01

    The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins,

  20. Conservation of silk genes in Trichoptera and Lepidoptera

    Czech Academy of Sciences Publication Activity Database

    Yonemura, N.; Mita, K.; Tamura, T.; Sehnal, František

    2009-01-01

    Roč. 68, č. 6 (2009), s. 641-653 ISSN 0022-2844 R&D Projects: GA AV ČR IAA5007402 Institutional research plan: CEZ:AV0Z50070508 Keywords : silk evolution * Trichoptera * Lepidoptera Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.323, year: 2009

  1. Nutrient Deprivation Induces Property Variations in Spider Gluey Silk

    Science.gov (United States)

    Blamires, Sean J.; Sahni, Vasav; Dhinojwala, Ali; Blackledge, Todd A.; Tso, I-Min

    2014-01-01

    Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition. PMID:24523902

  2. Effect of polyamines on mechanical and structural properties of Bombyx mori silk.

    Science.gov (United States)

    Yerra, Aparna; Mysarla, Danti Kumari; Siripurapu, Prasanthi; Jha, Anjali; Valluri, Satyavathi V; Mamillapalli, Anitha

    2017-01-01

    Silkworm, Bombyx mori (B. mori) belongs to the Lepidoptera family. The silk produced from this insect, mulberry silk, gained lot of importance as a fabric. Silk is being exploited as a biomaterial due to its surprising strength and biocompatibility. Polyamines (PA) are important cell growth regulators. In the present work the effect of treatment of polyamines, putrescine (Put), spermidine (Spd), and spermine (Spm) on the quantity and quality of silk produced was assessed. Results showed that exogenous feeding of Spd at a concentration of 50 µM increased fiber length significantly. Analysis by Fourier transform infrared (FTIR) on the properties of silk obtained from Spd treated silkworms revealed an increase in percentage of absorption with no difference in peak positions of amide I and amide III groups. Scanning electron microscopy (SEM) revealed an increase in diameter of silk. Further, analysis at molecular level showed an increase in fibroin expression in Spd treated silk glands. However, the Spd treatment showed no significant difference with respect to fibroin to sericin ratio per unit weight of cocoon, silk tenacity, and percent elongation. Thus, the present results show that polyamine treatment would influence silk quality at structural, mechanical, and molecular level in the Bombyx mori, which can be exploited in silk biomaterial production. © 2016 Wiley Periodicals, Inc.

  3. Co-effect of silk and amniotic membrane for tendon repair.

    Science.gov (United States)

    Seo, Young-Kwon; Kim, Jun-Hyung; Eo, Su-Rak

    2016-08-01

    The objective of the present study was to determine the feasibility and biocompatibility of a silk scaffold and a composite silk scaffold in terms of new tendon generation using a rabbit Achilles tendon model. The silk scaffold was constructed using a weaving machine, then soaked in a 1% collagen-hyaluronan (HA) solution and air-dried, whereas the composite silk scaffold was composed of a silk scaffold containing a lyophilized collagen-HA substrate. Tenocytes were cultured in vitro to compare cell populations in the two groups. The cellular densities on composite silk scaffolds were 40% higher on average than those on silk scaffolds in 30-day tenocyte cultures. The tendon scaffolds had implanted into Achilles tendon defects in 16 white New Zealand rabbits. Rabbits were randomly divided into the following three groups: group I, silk scaffold alone; group II, composite silk scaffold; and group III, composite silk scaffold wrapped by an amniotic membrane. Implants were harvested 2, 8, and 12 weeks post-implantation. Histological examinations were conducted using hematoxylin-eosin (H&E), Masson's trichrome, and by performing immunohistochemical staining for CD34. After 12 weeks, the three groups were distinguishable based on gross examination. The histological examination revealed more organized collagen fibrils in groups III, which showed a dense, parallel, linear organization of collagen bundles. CD34 staining revealed neoangiogenesis in groups III. The results of this research showed that collagen-HA substrates with amniotic membrane accelerate cellular migration and angiogenesis in neotendons.

  4. Analysis of proteome dynamics inside the silk gland lumen of Bombyx mori

    Science.gov (United States)

    Dong, Zhaoming; Zhao, Ping; Zhang, Yan; Song, Qianru; Zhang, Xiaolu; Guo, Pengchao; Wang, Dandan; Xia, Qingyou

    2016-01-01

    The silk gland is the only organ where silk proteins are synthesized and secreted in the silkworm, Bombyx mori. Silk proteins are stored in the lumen of the silk gland for around eight days during the fifth instar. Determining their dynamic changes is helpful for clarifying the secretion mechanism of silk proteins. Here, we identified the proteome in the silk gland lumen using liquid chromatography–tandem mass spectrometry, and demonstrated its changes during two key stages. From day 5 of the fifth instar to day 1 of wandering, the abundances of fibroins, sericins, seroins, and proteins of unknown functions increased significantly in different compartments of the silk gland lumen. As a result, these accumulated proteins constituted the major cocoon components. In contrast, the abundances of enzymes and extracellular matrix proteins decreased in the silk gland lumen, suggesting that they were not the structural constituents of silk. Twenty-five enzymes may be involved in the regulation of hormone metabolism for proper silk gland function. In addition, the metabolism of other non-proteinous components such as chitin and pigment were also discussed in this study. PMID:27102218

  5. Thermal Performance Testing of Cryogenic Multilayer Insulation with Silk Net Spacers

    International Nuclear Information System (INIS)

    Johnson, W L; Frank, D J; Nast, T C; Fesmire, J E

    2015-01-01

    Early comprehensive testing of cryogenic multilayer insulation focused on the use of silk netting as a spacer material. Silk netting was used for multiple test campaigns that were designed to provide baseline thermal performance estimates for cryogenic insulation systems. As more focus was put on larger systems, the cost of silk netting became a deterrent and most aerospace insulation firms were using Dacron (or polyester) netting spacers by the early 1970s. In the midst of the switch away from silk netting there was no attempt to understand the difference between silk and polyester netting, though it was widely believed that the silk netting provided slightly better performance. Without any better reference for thermal performance data, the silk netting performance correlations continued to be used. In order to attempt to quantify the difference between the silk netting and polyester netting, a brief test program was developed. The silk netting material was obtained from Lockheed Martin and was tested on the Cryostat-100 instrument in three different configurations, 20 layers with both single and double netting and 10 layers with single netting only. The data show agreement within 15 - 30% with the historical silk netting based correlations and show a substantial performance improvement when compared to previous testing performed using polyester netting and aluminum foil/fiberglass paper multilayer insulation. Additionally, the data further reinforce a recently observed trend that the heat flux is not directly proportional to the number of layers installed on a system. (paper)

  6. Improved strength of silk fibers in Bombyx mori trimolters induced by an anti-juvenile hormone compound.

    Science.gov (United States)

    Guo, Kaiyu; Dong, Zhaoming; Zhang, Yan; Wang, Dandan; Tang, Muya; Zhang, Xiaolu; Xia, Qingyou; Zhao, Ping

    2018-05-01

    Bombyx mori silk fibers with thin diameters have advantages of lightness and crease-resistance. Many studies have used anti-juvenile hormones to induce trimolters in order to generate thin silk; however, there has been comparatively little analysis of the morphology, structure and mechanical properties of trimolter silk. This study induced two kinds of trimolters by appling topically anti-juvenile hormones and obtained thin diameter silk. Scanning electron microscope (SEM), FTIR analysis, tensile mechanical testing, chitin staining were used to reveal that the morphology, conformation and mechanical property of the trimolter silk. Cocoon of trimolters were highly densely packed by thinner fibers and thus had small apertures. We found that the conformation of trimolter silk fibroin changed and formed more β-sheet structures. In addition, analysis of mechanical parameters yielded a higher Young's modulus and strength in trimolter silk than in the control. By chitin staining of silk gland, we postulated that the mechanical properties of trimolters' silk was enhanced greatly during to the structural changes of silk gland. We induced trimolters by anti-juvenile hormones and the resulting cocoons were more closely packed and had smaller silk fiber diameters. We found that the conformation of trimolters silk fibroin had a higher content of β-sheet structures and better mechanical properties. Our study revealed the structures and mechanical properties of trimolter silk, and provided a valuable reference to improve silk quality by influencing molting in silkworms. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Genetic engineered color silk: fabrication of a photonics material through a bioassisted technology.

    Science.gov (United States)

    Shimizu, Katsuhiko

    2018-05-15

    Silk produced by the silkworm Bombyx mori is an attractive material because of its luster, smooth and soft texture, conspicuous mechanical strength, good biocompatibility, slow biodegradation, and carbon neutral synthesis. Silkworms have been domesticated and bred for production of better quality and quantity of silk, resulting in the development of sericulture and the textile industry. Silk is generally white, so dyeing is required to obtain colored fiber. However, the dyeing process involves harsh conditions and generates a large volume of waste water, which have environmentally and economically negative impacts. Although some strains produce cocoons that contain pigments derived from the mulberry leaves that they eat, the pigments are distributed in the sericin layer and are lost during gumming. In trials for production of colored silk by feeding silkworms on diets containing dyes, only limited species of dye molecules were incorporated into the silk threads. A method for the generation of transgenic silkworm was established in conjunction with the discovery of green fluorescent protein (GFP), and silkworms carrying the GFP gene spun silk threads that formed cocoons that glowed bright green and still retained the original properties of silk. A wide range of color variation of silk threads has been obtained by replacing the GFP gene with the genes of other fluorescent proteins chosen from the fluorescent protein palette. The genetically modified silk with photonic properties can be processed to form various products including linear threads, 2D fabrics, and 3D materials. The transgenic colored silk could be economically advantageous due to addition of a new value to silk and reduction of cost for water waste, and environmentally preferable for saving water. Here, I review the literature regarding the production methods of fluorescent silk from transgenic silkworms and present examples of genetically modified color silk.

  8. Osteoinductive recombinant silk fusion proteins for bone regeneration.

    Science.gov (United States)

    Dinjaski, Nina; Plowright, Robyn; Zhou, Shun; Belton, David J; Perry, Carole C; Kaplan, David L

    2017-02-01

    Protein polymers provide a unique opportunity for tunable designs of material systems due to the genetic basis of sequence control. To address the challenge of biomineralization interfaces with protein based materials, we genetically engineered spider silks to design organic-inorganic hybrid systems. The spider silk inspired domain (SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQGT) 15 served as an organic scaffold to control material stability and to allow multiple modes of processing, whereas the hydroxyapatite binding domain VTKHLNQISQSY (VTK), provided control over osteogenesis. The VTK domain was fused either to the N-, C- or both terminals of the spider silk domain to understand the effect of position on material properties and mineralization. The addition of the VTK domain to silk did not affect the physical properties of the silk recombinant constructs, but it had a critical role in the induction of biomineralization. When the VTK domain was placed on both the C- and N-termini the formation of crystalline hydroxyapatite was significantly increased. In addition, all of the recombinant proteins in film format supported the growth and proliferation of human mesenchymal stem cells (hMSCs). Importantly, the presence of the VTK domain enhanced osteoinductive properties up to 3-fold compared to the control (silk alone without VTK). Therefore, silk-VTK fusion proteins have been shown suitable for mineralization and functionalization for specific biomedical applications. Organic-inorganic interfaces are integral to biomaterial functions in many areas of repair and regeneration. Several protein polymers have been investigated for this purpose. Despite their success the limited options to fine-tune their material properties, degradation patterns and functionalize them for each specific biomedical application limits their application. Various studies have shown that the biological performance of such proteins can be improved by genetic engineering. The present study provides data

  9. Multilayered dense collagen-silk fibroin hybrid: a platform for mesenchymal stem cell differentiation towards chondrogenic and osteogenic lineages.

    Science.gov (United States)

    Ghezzi, Chiara E; Marelli, Benedetto; Donelli, Ilaria; Alessandrino, Antonio; Freddi, Giuliano; Nazhat, Showan N

    2017-07-01

    Type I collagen is a major structural and functional protein in connective tissues. However, collagen gels exhibit unstable geometrical properties, arising from extensive cell-mediated contraction. In an effort to stabilize collagen-based hydrogels, plastic compression was used to hybridize dense collagen (DC) with electrospun silk fibroin (SF) mats, generating multilayered DC-SF-DC constructs. Seeded mesenchymal stem cell (MSC)-mediated DC-SF-DC contraction, as well as growth and differentiation under chondrogenic and osteogenic supplements, were compared to those seeded in DC and on SF alone. The incorporation of SF within DC prevented extensive cell-mediated collagen gel contraction. The effect of the multilayered hybrid on MSC remodelling capacity was also evident at the transcription level, where the expression of matrix metalloproteinases and their inhibitor (MMP1, MMP2, MMP3, MMP13 and Timp1) by MSCs within DC-SF-DC were comparable to those on SF and significantly downregulated in comparison to DC, except for Timp1. Chondrogenic supplements stimulated extracellular matrix production within the construct, stabilizing its multilayered structure and promoting MSC chondrogenic differentiation, as indicated by the upregulation of the genes Col2a1 and Agg and the production of collagen type II. In osteogenic medium there was an upregulation in ALP and OP along with the presence of an apatitic phase, indicating MSC osteoblastic differentiation and matrix mineralization. In sum, these results have implications on the modulation of three-dimensional collagen-based gel structural stability and on the stimulation and maintenance of the MSC committed phenotype inherent to the in vitro formation of chondral tissue and bone, as well as on potential multilayered complex tissues. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Identification of circular RNA in the Bombyx mori silk gland.

    Science.gov (United States)

    Gan, Huaiyan; Feng, Tieshan; Wu, Yuqian; Liu, Chun; Xia, Qingyou; Cheng, Tingcai

    2017-10-01

    Bombyx mori is an economically important holometabolous lepidopteran insect. In B. mori endogenous noncoding RNAs such as microRNAs (miRNAs) and Piwi-interacting RNAs play crucial biological functions in metamorphosis and sex determination. In addition, circular RNAs (circRNAs) have been recently identified as noncoding RNAs in most common model organisms and show potential as gene regulators. However, to date, there have been few studies on the circRNAs present in the B. mori genome conducted to date. Here, we identified 3916 circRNAs by deep circular transcriptome sequencing using the silk gland of B. mori. 3155 circRNAs were found to be derived from 1727 parental genes. The circRNAs displayed tissue-specific expression between the middle silk gland (MSG) and posterior silk gland (PSG), with 2532 and 880 being upregulated circRNAs in the MSG and PSG, respectively. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that the parental genes from the MSG and PSG were generally annotated to similar categories and pathways. The interaction network of circRNAs and miRNAs showed that circRNAs might act as miRNA sponges or interact with miRNAs in some other way. Overall, the results revealed the complicated patterns of circRNAs in the B. mori silk gland providing a new angle from which to explore the mechanisms of complex gene regulation and efficient silk protein synthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Preparation and characterization of electrospun poly(phthalazinone ether nitrile ketone) membrane with novel thermally stable properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Gang; Zhang, Hao; Qian, Bingqing [Carbon Research Laboratory, Liaoning Key Lab for Energy Materials and Chemical Engineering, State Key Lab of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China); Wang, Jinyan, E-mail: wangjinyan@dlut.edu.cn [Department of Polymer Science and Materials, Dalian University of Technology, Dalian 116024 (China); Jian, Xigao [Department of Polymer Science and Materials, Dalian University of Technology, Dalian 116024 (China); Qiu, Jieshan, E-mail: jqiu@dlut.edu.cn [Carbon Research Laboratory, Liaoning Key Lab for Energy Materials and Chemical Engineering, State Key Lab of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China)

    2015-10-01

    Highlights: • Poly (phthalazinone ether nitrile ketone) (PPENK) was used to successfully prepare nanofiber membranes by electrospinning. • Electrospun membrane exhibits a good thermostability. • Electrospun membrane. - Abstract: Electrospun nanofibrous membranes have several applications because of their excellent properties, such as high porosity, small fiber diameter, and large surface area. However, high-temperature resistant electrospun membranes remain a challenge because of the absence of precursors that offer spinnability, scalability, and superior thermal stability. In this study, poly(phthalazinone ether nitrile ketone) (PPENK) was used to successfully prepare nanofiber membranes by electrospinning. Electrospun PPENK membranes were characterized by scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and tensile stress–strain tests. Results indicated that the prepared electrospun membranes had a very high glass transition temperature, superior chemical resistance, and excellent mechanical strength. These desirable properties broaden their potential application in membranes and treatment of various hot fluid streams without strict temperature control.

  12. Processing and characterization of α-elastin electrospun membranes

    Science.gov (United States)

    Araujo, J.; Padrão, J.; Silva, J. P.; Dourado, F.; Correia, D. M.; Botelho, G.; Gomez Ribelles, J. L.; Lanceros-Méndez, S.; Sencadas, V.

    2014-06-01

    Elastin isolated from fresh bovine ligaments was dissolved in a mixture of 1,1,1,3,3,3-Hexafluoro-2-propanol and water were electrospun into fiber membranes under different processing conditions. Fiber mats of randomly and aligned fibers were obtained with fixed and rotating ground collectors and fibrils were composed by thin ribbons whose width depends on electrospinning conditions; fibrils with 721 nm up to 2.12 μm width were achieved. After cross-linking with glutaraldehyde, α-elastin can uptake as much as 1700 % of PBS solution and a slight increase on fiber thickness was observed. The glass transition temperature of electrospun fiber mats was found to occur at ˜80 °C. Moreover, α-Elastin showed to be a perfect elastomeric material, and no mechanical hysteresis was found in cycle mechanical measurements. The elastic modulus obtained for random and aligned fibers mats in a PBS solution was 330±10 kPa and 732±165 kPa, respectively. Finally, the electrospinning and cross-linking process does not inhibit MC-3T3-E1 cell adhesion. Cell culture results showed good cell adhesion and proliferation in the cross-linked elastin fiber mats.

  13. Electrospun polydioxanone-elastin blends: potential for bioresorbable vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Sell, S A [Virginia Commonwealth University, Richmond, VA 23298 (United States); McClure, M J [Virginia Commonwealth University, Richmond, VA 23298 (United States); Barnes, C P [Virginia Commonwealth University, Richmond, VA 23298 (United States); Knapp, D C [Virginia Commonwealth University, Richmond, VA 23298 (United States); Walpoth, B H [University Hospital, 1211 Geneva 14 (Switzerland); Simpson, D G [Virginia Commonwealth University, Richmond, VA 23298 (United States); Bowlin, G L [Virginia Commonwealth University, Richmond, VA 23298 (United States)

    2006-06-15

    An electrospun cardiovascular graft composed of polydioxanone (PDO) and elastin has been designed and fabricated with mechanical properties to more closely match those of native arterial tissue, while remaining conducive to tissue regeneration. PDO was chosen to provide mechanical integrity to the prosthetic, while elastin provides elasticity and bioactivity (to promote regeneration in vitro/in situ). It is the elastic nature of elastin that dominates the low-strain mechanical response of the vessel to blood flow and prevents pulsatile energy from being dissipated as heat. Uniaxial tensile and suture retention tests were performed on the electrospun grafts to demonstrate the similarities of the mechanical properties between the grafts and native vessel. Dynamic compliance measurements produced values that ranged from 1.2 to 5.6%/100 mmHg for a set of three different mean arterial pressures. Results showed the 50:50 ratio to closely mimic the compliance of native femoral artery, while grafts that contained less elastin exceeded the suture retention strength of native vessel. Preliminary cell culture studies showed the elastin-containing grafts to be bioactive as cells migrated through their full thickness within 7 days, but failed to migrate into pure PDO scaffolds. Electrospinning of the PDO and elastin-blended composite into a conduit for use as a small diameter vascular graft has extreme potential and warrants further investigation as it thus far compares favorably to native vessel.

  14. In vitro evaluation of crosslinked electrospun fish gelatin scaffolds.

    Science.gov (United States)

    Gomes, S R; Rodrigues, G; Martins, G G; Henriques, C M R; Silva, J C

    2013-04-01

    Gelatin from cold water fish skin was electrospun, crosslinked and investigated as a substrate for the adhesion and proliferation of cells. Gelatin was first dissolved in either water or concentrated acetic acid and both solutions were successfully electrospun. Cross-linking was achieved via three different routes: glutaraldehyde vapor, genipin and dehydrothermal treatment. Solution's properties (surface tension, electrical conductivity and viscosity) and scaffold's properties (chemical bonds, weight loss and fiber diameters) were measured. Cellular viability was analyzed culturing 3T3 fibroblasts plated on the scaffolds and grown up to 7 days. The cells were fixed and observed with SEM or stained for DNA and F-actin and observed with confocal microscopy. In all scaffolds, the cells attached and spread with varying degrees. The evaluation of cell viability showed proliferation of cells until confluence in scaffolds crosslinked by glutaraldehyde and genipin; however the rate of growth in genipin crosslinked scaffolds was slow, recovering only by day five. The results using the dehydrothermal treatment were the less satisfactory. Our results show that glutaraldehyde treated fish gelatin is the most suitable substrate, of the three studied, for fibroblast adhesion and proliferation. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Nanocarbons in Electrospun Polymeric Nanomats for Tissue Engineering: A Review

    Directory of Open Access Journals (Sweden)

    Roberto Scaffaro

    2017-02-01

    Full Text Available Electrospinning is a versatile process technology, exploited for the production of fibers with varying diameters, ranging from nano- to micro-scale, particularly useful for a wide range of applications. Among these, tissue engineering is particularly relevant to this technology since electrospun fibers offer topological structure features similar to the native extracellular matrix, thus providing an excellent environment for the growth of cells and tissues. Recently, nanocarbons have been emerging as promising fillers for biopolymeric nanofibrous scaffolds. In fact, they offer interesting physicochemical properties due to their small size, large surface area, high electrical conductivity and ability to interface/interact with the cells/tissues. Nevertheless, their biocompatibility is currently under debate and strictly correlated to their surface characteristics, in terms of chemical composition, hydrophilicity and roughness. Among the several nanofibrous scaffolds prepared by electrospinning, biopolymer/nanocarbons systems exhibit huge potential applications, since they combine the features of the matrix with those determined by the nanocarbons, such as conductivity and improved bioactivity. Furthermore, combining nanocarbons and electrospinning allows designing structures with engineered patterns at both nano- and microscale level. This article presents a comprehensive review of various types of electrospun polymer-nanocarbon currently used for tissue engineering applications. Furthermore, the differences among graphene, carbon nanotubes, nanodiamonds and fullerenes and their effect on the ultimate properties of the polymer-based nanofibrous scaffolds is elucidated and critically reviewed.

  16. Stem cell responses to plasma surface modified electrospun polyurethane scaffolds.

    Science.gov (United States)

    Zandén, Carl; Hellström Erkenstam, Nina; Padel, Thomas; Wittgenstein, Julia; Liu, Johan; Kuhn, H Georg

    2014-07-01

    The topographical effects from functional materials on stem cell behavior are currently of interest in tissue engineering and regenerative medicine. Here we investigate the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell (hESC) and rat postnatal neural stem cell (NSC) responses. The plasma gases were found to induce three combinations of fiber surface functionalities and roughness textures. On randomly oriented fibers, plasma treatments lead to substantially increased hESC attachment and proliferation as compared to native fibers. Argon plasma was found to induce the most optimal combination of surface functionality and roughness for cell expansion. Contact guided migration of cells and alignment of cell processes were observed on aligned fibers. Neuronal differentiation around 5% was found for all samples and was not significantly affected by the induced variations of surface functional group distribution or individual fiber topography. In this study the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell and rat postnatal neural stem cell (NSC) responses is studied with the goal of clarifying the potential effects of functional materials on stem cell behavior, a topic of substantial interest in tissue engineering and regenerative medicine. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Lipid-mediated protein functionalization of electrospun polycaprolactone fibers

    Directory of Open Access Journals (Sweden)

    C. Cohn

    2016-05-01

    Full Text Available In this study, electrospun polycaprolactone (PCL fibers are plasma-treated and chemically conjugated with cholesteryl succinyl silane (CSS. In addition to Raman spectroscopy, an immobilization study of DiO as a fluorescent probe of lipid membranes provides evidence supporting the CSS coating of plasma-treated PCL fibers. Further, anti-CD20 antibodies are used as a model protein to evaluate the potential of lipid-mediated protein immobilization as a mechanism to functionalize the CSS-PCL fiber scaffolds. Upon anti-CD20 functionalization, the CSS-PCL fiber scaffolds capture Granta-22 cells 2.4 times more than the PCL control does, although the two fiber scaffolds immobilize a comparable amount of anti-CD20. Taken together, results from the present study demonstrate that the CSS coating and CSS-mediated antibody immobilization offers an appealing strategy to functionalize electrospun synthetic polymer fibers and confer cell-specific functions on the fiber scaffolds, which can be mechanically robust but often lack biological functions.

  18. On the Adhesion performance of a single electrospun fiber

    Science.gov (United States)

    Baji, Avinash; Zhou, Limin; Mai, Yiu-Wing; Yang, Zhifang; Yao, Haimin

    2015-01-01

    The micro- and nano-scale fibrillar structures found on the feet of spiders and geckos function as adhesion devices which allow them to adhere to both molecularly smooth and rough surfaces. This adhesion has been argued to arise from intermolecular forces, such as van der Waals (vdW) force, acting at the interface between any two materials in contact. Thus, it is possible to mimic their adhesion using synthetic nanostructured analogs. Herein, we report the first successful pull-off force measurements on a single electrospun fiber and show the potential of using electrospinning to fabricate adhesive analogs. A single fiber is glued to the atomic force microscope cantilever, and its adhesion to a metal substrate is studied by recording the pull-off force/displacement curves. The measured adhesive force of ~18 nN matches closely that of their biological counterparts. Similar to natural structures, the adhesive mechanism of these electrospun structures is controlled by vdW interactions.

  19. Sample selection, preparation methods, and the apparent tensile properties of silkworm (B. mori) cocoon silk.

    Science.gov (United States)

    Reed, Emily J; Bianchini, Lindsay L; Viney, Christopher

    2012-06-01

    Reported literature values of the tensile properties of natural silk cover a wide range. While much of this inconsistency is the result of variability that is intrinsic to silk, some is also a consequence of differences in the way that silk is prepared for tensile tests. Here we explore how measured mechanical properties of Bombyx mori cocoon silk are affected by two intrinsic factors (the location from which the silk is collected within the cocoon, and the color of the silk), and two extrinsic factors (the storage conditions prior to testing, and different styles of reeling the fiber). We find that extrinsic and therefore controllable factors can affect the properties more than the intrinsic ones studied. Our results suggest that enhanced inter-laboratory collaborations, that lead to standardized sample collection, handling, and storage protocols prior to mechanical testing, would help to decrease unnecessary (and complicating) variation in reported tensile properties. Copyright © 2011 Wiley Periodicals, Inc.

  20. Concentration state dependence of the rheological and structural properties of reconstituted silk.

    Science.gov (United States)

    Mo, Chunli; Holland, Chris; Porter, David; Shao, Zhengzhong; Vollrath, Fritz

    2009-10-12

    The ability to control the processing of artificial silk is key to the successful application of this important and high performance biopolymer. Understanding where our current reconstitution process can be improved will not only aid us in the creation of better materials, but will also provide insight into the natural material along the way. This study aims to understand what proportion of reconstituted silk contributes to its rheological properties and what conformational state the silk proteins are in. It shows, for the first time, that a change in rheological properties can be related to a change in silk structures present in solution and reveals a low concentration gel state for silk that may have important implications for future successful artificial processing of silk.

  1. Invited review current progress and limitations of spider silk for biomedical applications.

    Science.gov (United States)

    Widhe, Mona; Johansson, Jan; Hedhammar, My; Rising, Anna

    2012-06-01

    Spider silk is a fascinating material combining remarkable mechanical properties with low density and biodegradability. Because of these properties and historical descriptions of medical applications, spider silk has been proposed to be the ideal biomaterial. However, overcoming the obstacles to produce spider silk in sufficient quantities and in a manner that meets regulatory demands has proven to be a difficult task. Also, there are relatively few studies of spider silk in biomedical applications available, and the methods and materials used vary a lot. Herein we summarize cell culture- and in vivo implantation studies of natural and synthetic spider silk, and also review the current status and future challenges in the quest for a large scale production of spider silk for medical applications. Copyright © 2011 Wiley Periodicals, Inc.

  2. Investigation of synthetic spider silk crystallinity and alignment via electrothermal, pyroelectric, literature XRD, and tensile techniques.

    Science.gov (United States)

    Munro, Troy; Putzeys, Tristan; Copeland, Cameron G; Xing, Changhu; Lewis, Randolph V; Ban, Heng; Glorieux, Christ; Wubbenhorst, Michael

    2017-04-01

    The processes used to create synthetic spider silk greatly affect the properties of the produced fibers. This paper investigates the effect of process variations during artificial spinning on the thermal and mechanical properties of the produced silk. Property values are also compared to the ones of the natural dragline silk of the N. clavipes spider, and to unprocessed (as-spun) synthetic silk. Structural characterization by scanning pyroelectric microscopy is employed to provide insight into the axial orientation of the crystalline regions of the fiber and is supported by XRD data. The results show that stretching and passage through liquid baths induce crystal formation and axial alignment in synthetic fibers, but with different structural organization than natural silks. Furthermore, an increase in thermal diffusivity and elastic modulus is observed with decreasing fiber diameter, trending towards properties of natural fiber. This effect seems to be related to silk fibers being subjected to a radial gradient during production.

  3. Spider genomes provide insight into composition and evolution of venom and silk

    Science.gov (United States)

    Sanggaard, Kristian W.; Bechsgaard, Jesper S.; Fang, Xiaodong; Duan, Jinjie; Dyrlund, Thomas F.; Gupta, Vikas; Jiang, Xuanting; Cheng, Ling; Fan, Dingding; Feng, Yue; Han, Lijuan; Huang, Zhiyong; Wu, Zongze; Liao, Li; Settepani, Virginia; Thøgersen, Ida B.; Vanthournout, Bram; Wang, Tobias; Zhu, Yabing; Funch, Peter; Enghild, Jan J.; Schauser, Leif; Andersen, Stig U.; Villesen, Palle; Schierup, Mikkel H; Bilde, Trine; Wang, Jun

    2014-01-01

    Spiders are ecologically important predators with complex venom and extraordinarily tough silk that enables capture of large prey. Here we present the assembled genome of the social velvet spider and a draft assembly of the tarantula genome that represent two major taxonomic groups of spiders. The spider genomes are large with short exons and long introns, reminiscent of mammalian genomes. Phylogenetic analyses place spiders and ticks as sister groups supporting polyphyly of the Acari. Complex sets of venom and silk genes/proteins are identified. We find that venom genes evolved by sequential duplication, and that the toxic effect of venom is most likely activated by proteases present in the venom. The set of silk genes reveals a highly dynamic gene evolution, new types of silk genes and proteins, and a novel use of aciniform silk. These insights create new opportunities for pharmacological applications of venom and biomaterial applications of silk. PMID:24801114

  4. Antibacterial effects of electrospun chitosan/poly(ethylene oxide) nanofibrous membranes loaded with chlorhexidine and silver

    NARCIS (Netherlands)

    Song, J.; Remmers, S.J.; Shao, J.; Kolwijck, E.; Walboomers, X.F.; Jansen, J.A.; Leeuwenburgh, S.C.; Yang, F.

    2016-01-01

    To prevent percutaneous device associated infections (PDAIs), we prepared electrospun chitosan/poly(ethylene oxide) (PEO) nanofibrous membrane containing silver nanoparticles as an implantable delivery vehicle for the dual release of chlorhexidine and silver ions. We observed that the silver

  5. Electrospun fish protein fibers as a biopolymer-based carrier – implications for oral protein delivery

    DEFF Research Database (Denmark)

    Boutrup Stephansen, Karen; García-Díaz, María; Jessen, Flemming

    2014-01-01

    Purpose: Protein-based electrospun fibers have emerged as novel nanostructured materials for tissue engineering and drug delivery due to their unique structural characteristics, biocompatibility and biodegradability. The aim of this study was to explore the use of electrospun fibers based on fish...... sarcoplasmic proteins as an oral delivery platform for biopharmaceuticals, using insulin as a model protein. Methods: Fish sarcoplasmic proteins (FSP) were isolated from fresh cod and electrospun into nanomicrofibers using insulin as a model payload. The morphology of FSP fibers was characterized using...... differentiated Caco-2 cell monolayers was followed by RP-HPLC and ELISA, and the transepithelial electrical resistance (TEER) was measured before and after the experiment. Cell viability was assessed by the MTS/PMS assay. Results: Insulin was encapsulated in the electrospun FSP fibers with high efficiency, high...

  6. Electrospun bioactive mats enriched with Ca-polyphosphate/retinol nanospheres as potential wound dressing

    OpenAIRE

    Müller, Werner E.G.; Tolba, Emad; Dorweiler, Bernhard; Schröder, Heinz C.; Diehl-Seifert, Bärbel; Wang, Xiaohong

    2015-01-01

    Background While electrospun materials have been frequently used in tissue engineering no wound dressings exist that significantly improved wound healing effectively. Methods We succeeded to fabricate three-dimensional (3D) electrospun poly(D,l-lactide) (PLA) fiber mats into which nanospheres, formed from amorphous calcium polyphosphate (polyP) nanoparticles (NP) and encapsulated retinol (“retinol/aCa-polyP-NS” nanospheres [NS]), had been incorporated. Results Experiments with MC3T3-E1 cells ...

  7. Dissolvable Films of Silk Fibroin for Ultrathin Conformal Bio-Integrated Electronics

    Science.gov (United States)

    2010-06-01

    implantation. *A full list of authors and their affiliations appears at the end of the paper. Silk is an appealing biopolymer as a temporary, soluble...18 APR 2010 2. REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Dissolvable films of silk fibroin for ultrathin...10.1038/NMAT2745 Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics Dae-Hyeong Kim and Jonathan Viventi et al

  8. Graphene oxide from silk cocoon: a novel magnetic fluorophore for multi-photon imaging

    OpenAIRE

    Roy, Manas; Kusurkar, Tejas Sanjeev; Maurya, Sandeep Kumar; Meena, Sunil Kumar; Singh, Sushil Kumar; Sethy, Niroj; Bhargava, Kalpana; Sharma, Raj Kishore; Goswami, Debabrata; Sarkar, Sabyasachi; Das, Mainak

    2013-01-01

    In this work, we synthesized graphene oxide from silk cocoon embarking its new dimension as a magnetic fluorophore when compared with its present technical status, which at best is for extracting silk as a biomaterial for tissue engineering applications. We produced graphene oxide by pyrolysing the silk cocoon in an inert atmosphere. The collected raw carbon is oxidized by nitric acid that readily produces multilayer graphene oxide with nano carbon particulates. Structural properties of the g...

  9. Physico-chemical study of flavonoids from different matureness corn silk material

    OpenAIRE

    Li, Peng; Lapčík, Lubomír; Lapčíková, Barbora; Kalytchuk, Sergii

    2018-01-01

    There was tested a simple extraction procedure of flavonoids separation from the original corn silk (CS) material. It was found, that the total flavonoids content differs with the extraction time and extraction temperature. There were found different flavonoids contents in extracts prepared from different maturity stages of the original corn silk material (silking stage (CS-S), milky stage (CS-M)). Extracted flavonoids content was quantified by the lutin standardization method by means of col...

  10. Evaluating drug trafficking on the Tor Network: Silk Road 2, the sequel.

    Science.gov (United States)

    Dolliver, Diana S

    2015-11-01

    Housing an illicit, online drug retail market generating sales in the millions of USD, the Silk Road was a profitable marketplace with a growing and loyal consumer base. Following its FBI-forced shut down in October 2013, the Silk Road enjoyed newfound fame that contributed to an increase in new users downloading and accessing the Tor Network; however, with this particular marketplace out of order, Silk Road 2 was launched to fill the void. The goals of this study were to (1) compare the metrics of Silk Road 2 to the original site, and to (2) determine if there were any indications of the presence of more sophisticated drug trafficking operations. Data were collected from Silk Road 2 during the months of August and September 2014 using webcrawling software. Silk Road 2 was a much smaller marketplace than the original Silk Road. Of the 1834 unique items for sale, 348 were drug items sold by 145 distinct vendors shipping from 19 countries. Of the drug items advertised, most were stimulants and hallucinogens. The United States is both the number one country of origin for drug sales on Silk Road 2 and the number one destination country. Interestingly, 73% of all vendor accounts on Silk Road 2 advertised drug items, even though drugs only constituted 19% of all items advertised. This study was the first to research Silk Road 2, the replacement illicit marketplace to the original virtual Silk Road. This study was also the first to examine indications of the presence of more coordinated drug trafficking efforts in an online setting. The findings indicated that while Silk Road 2 was not primarily a drug market, there were indications that some vendor accounts may have connections reaching beyond a base retail market. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    OpenAIRE

    Christine Radtke

    2016-01-01

    Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropo...

  12. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Science.gov (United States)

    Gajos, Katarzyna; Budkowski, Andrzej; Tsialla, Zoi; Petrou, Panagiota; Awsiuk, Kamil; Dąbczyński, Paweł; Bernasik, Andrzej; Rysz, Jakub; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios

    2017-07-01

    Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si3N4-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si3N4 surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency increases with the printing probe concentration.

  13. Resorbable electrospun polydioxanone fibres modify the behaviour of cells from both healthy and diseased human tendons

    Directory of Open Access Journals (Sweden)

    A Kendal

    2017-02-01

    Full Text Available Chronic tendinopathy in an active and ageing population represents an increasing burden to healthcare systems. Rotator cuff tendinopathy alone accounts for approximately 70 % of all shoulder pain. Tendinopathic tissue has a disorganised extracellular matrix, altered vasculature, and infiltration of fibroblasts and inflammatory cells. This altered biology may contribute to the limited success of surgical repair strategies. Electrospun resorbable scaffolds can potentially enhance endogenous repair mechanisms by influencing the tissue microenvironment. Polydioxanone (PDO has an established safety profile in patients. We compared the response of healthy and diseased human tendon cells to electrospun PDO fibres using live cell imaging, proliferation, flow cytometry, and gene expression studies. Within 4 h of initial contact with electrospun PDO, healthy tendon cells underwent a marked transformation; elongating along the fibres in a fibre density dependent manner. Diseased tendon cells initially responded at a slower rate, but ultimately underwent a similar morphological change. Electrospun fibres increased the proliferation rate of diseased tendon cells and increased the ratio of type I:IIIcollagenmRNA expression. Flow cytometry revealed decreased expression of CD106, a marker of mesenchymal stem cells, and increased expression of CD10 on healthy versus diseased tendon cells. PDO electrospun scaffolds further promoted CD106negCD10pos expression of healthy tendon cells. Despite their behavioural differences, both healthy and diseased human tendon cells responded to electrospun PDO fibres. This encourages further work establishing their efficacy in augmenting surgical repair of diseased tendons.

  14. Utilizing NaCl to increase the porosity of electrospun materials

    International Nuclear Information System (INIS)

    Wright, L.D.; Andric, T.; Freeman, J.W.

    2011-01-01

    Electrospinning has emerged as a popular method for creating scaffolding materials used in tissue engineering applications to repair or replace damaged tissues. To become a viable scaffold material, however, pore sizes in electrospun materials must be increased to improve cell infiltration. Deposition of NaCl crystals during electrospinning was utilized to help overcome this obstacle. The NaCl crystals are released above the rotating collection mandrel and become incorporated into the poly(L-lactide) electrospun material. The NaCl then leaches out of the electrospun material creating larger pores: average pore diameter of 48.7 μm for PLLA-NaCl electrospinning versus 5.5 μm for PLLA alone electrospinning. Electrospun PLLA scaffolds with NaCl pores have a lower elastic modulus (8.05 MPa) and yield stress (349 kPa) and a higher yield strain (0.04) compared to their traditional counterparts (40.36 MPa, 676 kPa, and 0.0188). Decreased elastic modulus and yield stress would be beneficial to tissue engineering of elastic tissues including skin. The presence of NaCl pores did not significantly affect the cellular proliferation of MC3T3 cells but did allow for cell infiltration into the electrospun material. Therefore, the creation of large pores through NaCl leaching can significantly improve the performance of electrospun materials for tissue engineering applications by improving cellular infiltration.

  15. Characterization and assembly of a GFP-tagged cylindriform silk into hexameric complexes.

    Science.gov (United States)

    Öster, Carl; Svensson Bonde, Johan; Bülow, Leif; Dicko, Cedric

    2014-04-01

    Spider silk has been studied extensively for its attractive mechanical properties and potential applications in medicine and industry. The production of spider silk, however, has been lagging behind for lack of suitable systems. Our approach focuses on solving the production of spider silk by designing, expressing, purifying and characterizing the silk from cylindriform glands. We show that the cylindriform silk protein, in contrast to the commonly used dragline silk protein, is fully folded and stable in solution. With the help of GFP as a fusion tag we enhanced the expression of the silk protein in Escherichia coli and could optimize the downstream processing. Secondary structures analysis by circular dichroism and FTIR shows that the GFP-silk fusion protein is predominantly α-helical, and that pH can trigger a α- to β-transition resulting in aggregation. Structural analysis by small angle X-ray scattering suggests that the GFP-Silk exists in the form of a hexamer in solution. Copyright © 2013 Wiley Periodicals, Inc.

  16. Silk Composite with a Fluoropolymer as a Water-Resistant Protein-Based Material

    Directory of Open Access Journals (Sweden)

    Keiji Numata

    2018-04-01

    Full Text Available Silk-based materials are water-sensitive and show different physical properties at different humidities and under wet/dry conditions. To overcome the water sensitivity of silk-based materials, we developed a silk composite material with a fluoropolymer. Blending and coating the silk protein-based materials, such as films and textiles, with the fluoropolymer enhanced the surface hydrophobicity, water vapor barrier properties, and size stability during shrinkage tests. This material design with a protein biopolymer and a fluoropolymer is expected to broaden the applicability of protein-based materials.

  17. Flame retardancy and ultraviolet resistance of silk fabric coated by graphene oxide

    Directory of Open Access Journals (Sweden)

    Ji Yi-Min

    2017-01-01

    Full Text Available Silk fabrics were coated by graphene oxide hydrosol in order to improve its flame retardancy and ultraviolet resistance. In addition, montmorillonoid was doped into the graphene oxide hydrosol to further improve the flame retardancy of silk fabrics. The flame retardancy and ultraviolet resistance were mainly characterized by limiting oxygen index, vertical flame test, smoke density test, and ultraviolet protection factor. The synergistic effect of graphene oxide and montmorillonoid on the thermal stabilization property of the treated silk fabrics was also investigated. The results show that the treated silk fabrics have excellent flame retardancy, thermal stability, smoke suppression, and ultraviolet resistance simultaneously.

  18. Nutritional compositions and antioxidative capacity of the silk obtained from immature and mature corn

    Directory of Open Access Journals (Sweden)

    Nurhanan Abdul Rahman

    2014-04-01

    Full Text Available The silks of immature and mature corn were evaluated for their variations in nutritional compositions, mineral content and antioxidant capacity. Both immature and mature silks were good source of nutritional compositions. Immature silks contained significantly higher moisture (89.31% (fresh basis, lipid (1.27% and protein (12.96% content than the mature silk. Mature silks contained higher composition of ash (5.51%, carbohydrate (29.74% and total dietary fiber (51.25 g/100 g, than the immature silk, but the difference was not significant. In mineral determination, immature silk was rich source of Ca (1087.08 μg/g, Mg (1219.17 μg/g, Cu (5.60 μg/g and Zn (46.37 μg/g than the mature silks. In contrast, other minerals such as K (35671.67 μg/g, Na (266.67 μg/g, Fe (4.50 μg/g and Mn (35.57 μg/g were found higher in the mature silk. The silks were extracted with ethyl acetate, ethanol and water using the Soxhlet extraction method to determine the polyphenol and ABTS radical scavenging capacity. From this study, the highest content of total polyphenol of immature silks was exhibited by ethanol extract (92.21 mg GAE/g while water extract (64.22 mg GAE/g had the highest polyphenol content among mature silk extracts. Total flavonoid content of both immature and mature silks was higher in the water extract at 8.40 mg CAE/g and 2.31 mg CAE/g, respectively. In the ABTS free radical assay method, all immature silk extracts had higher percentage of inhibition compared to the mature silks. Among all three crude extracts, the ethanol extract of immature (EC50 = 0.478 mg/ml and mature silk (EC50 = 0.799 mg/ml exhibited the strongest antioxidant capacity followed by the water and ethyl acetate extract.

  19. A highly divergent gene cluster in honey bees encodes a novel silk family

    OpenAIRE

    Sutherland, Tara D.; Campbell, Peter M.; Weisman, Sarah; Trueman, Holly E.; Sriskantha, Alagacone; Wanjura, Wolfgang J.; Haritos, Victoria S.

    2006-01-01

    The pupal cocoon of the domesticated silk moth Bombyx mori is the best known and most extensively studied insect silk. It is not widely known that Apis mellifera larvae also produce silk. We have used a combination of genomic and proteomic techniques to identify four honey bee fiber genes (AmelFibroin1–4) and two silk-associated genes (AmelSA1 and 2). The four fiber genes are small, comprise a single exon each, and are clustered on a short genomic region where the open reading frames are GC-r...

  20. Biobased silver nanocolloid coating on silk fibers for prevention of post-surgical wound infections

    Directory of Open Access Journals (Sweden)

    Dhas SP

    2015-10-01

    Full Text Available Sindhu Priya Dhas, Suruthi Anbarasan, Amitava Mukherjee, Natarajan Chandrasekaran Center for Nanobiotechnology, VIT University, Vellore, India Abstract: Bombyx mori silk fibers are an important biomaterial and are used in surgical sutures due to their remarkable biocompatibility. The major drawback to the application of biomaterials is the risk of bacterial invasion, leading to clinical complications. We have developed an easy and cost-effective method for fabrication of antibacterial silk fibers loaded with silver nanoparticles (AgNPs by an in situ and ex situ process using an aqueous extract of Rhizophora apiculata leaf. Scanning electron microscopy revealed that well dispersed nanoparticles impregnated the silk fibers both in situ and ex situ. The crystalline nature of the AgNPs in the silk fibers was demonstrated by X-ray diffraction. The thermal and mechanical properties of the silk fibers were enhanced after they were impregnated with AgNPs. The silver-coated silk fibers fabricated by the in situ and ex situ method exhibited more than 90% inhibition against Pseudomonas aeruginosa and Staphylococcus aureus. Silk fibers doped with AgNPs were found to be biocompatible with 3T3 fibroblasts. The results obtained represent an important advance towards the clinical application of biocompatible AgNP-loaded silk fibers for prevention of surgical wound infections. Keywords: silk fibers, silver nanoparticles, antibacterial activity, wound infections, cytotoxicity, 3T3 fibroblast cells

  1. Structural and thermal properties of silk fibroin - Silver nanoparticles composite films

    Science.gov (United States)

    Shivananda, C. S.; Rao B, B. Lakshmeesha; Shetty, G. Rajesh; Sangappa, Y.

    2018-05-01

    In this work, silk fibroin-silver nanoparticles (SF-AgNPs) composite films have been prepared by simple solution casting method. The composite films were examined for structural and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results showed that with the introduction of AgNPs in the silk fibroin matrix the amorphous nature of the silk fibroin decreases with increasing nanoparticles concentration. The silk fibroin films possess good thermal stability with the presence of AgNPs.

  2. Radiation processing of silk protein (Bilateral research cooperation OAEP and JAERI. December 1998 - December 2002)

    International Nuclear Information System (INIS)

    2003-01-01

    Thailand's production of silk, about 1,200 ton per year, also gives about 10% of silk waste which is expected to be recycled into new material (non-textile application) and to avoid environmental pollution. For this purpose, cooperative program 'radiation processing of silk protein' was conducted between OAEP (Thailand) and JAERI. Among the results already obtained are: radiation degradation of silk protein (fibroin) with gamma rays at 160 kGy, production of fine silk milled powder (<90 microns) by electron beam irradiation at 250-1000 kGy (dry method) using electron accelerator (1 MeV, 1 mA), use of antioxidant effect of silk protein on lipid peroxidation and antibacterial activity of irradiated silk protein powder, and wound dressing hydrogel mixed with silk protein and use of antibacterial activity of cross-linked silk protein/PVA hydrogel. Other topics of interest are gamma irradiation of anionic natural polymer solution for use as latex protein scavenger and gamma radiation degradation of chitosan for use as plant growth promoter and fungicide. (S. Ohno)

  3. Silk fibroin-chondroitin sulfate scaffold with immuno-inhibition property for articular cartilage repair.

    Science.gov (United States)

    Zhou, Feifei; Zhang, Xianzhu; Cai, Dandan; Li, Jun; Mu, Qin; Zhang, Wei; Zhu, Shouan; Jiang, Yangzi; Shen, Weiliang; Zhang, Shufang; Ouyang, Hong Wei

    2017-11-01

    The demand of favorable scaffolds has increased for the emerging cartilage tissue engineering. Chondroitin sulfate (CS) and silk fibroin have been investigated and reported with safety and excellent biocompatibility as tissue engineering scaffolds. However, the rapid degradation rate of pure CS scaffolds presents a challenge to effectively recreate neo-tissue similar to natural articular cartilage. Meanwhile the silk fibroin is well used as a structural constituent material because its remarkable mechanical properties, long-lasting in vivo stability and hypoimmunity. The application of composite silk fibroin and CS scaffolds for joint cartilage repair has not been well studied. Here we report that the combination of silk fibroin and CS could synergistically promote articular cartilage defect repair. The silk fibroin (silk) and silk fibroin/CS (silk-CS) scaffolds were fabricated with salt-leaching, freeze-drying and crosslinking methodologies. The biocompatibility of the scaffolds was investigated in vitro by cell adhesion, proliferation and migration with human articular chondrocytes. We found that silk-CS scaffold maintained better chondrocyte phenotype than silk scaffold; moreover, the silk-CS scaffolds reduced chondrocyte inflammatory response that was induced by interleukin (IL)-1β, which is in consistent with the well-documented anti-inflammatory activities of CS. The in vivo cartilage repair was evaluated with a rabbit osteochondral defect model. Silk-CS scaffold induced more neo-tissue formation and better structural restoration than silk scaffold after 6 and 12weeks of implantation in ICRS histological evaluations. In conclusion, we have developed a silk fibroin/ chondroitin sulfate scaffold for cartilage tissue engineering that exhibits immuno-inhibition property and can improve the self-repair capacity of cartilage. Severe cartilage defect such as osteoarthritis (OA) is difficult to self-repair because of its avascular, aneural and alymphatic nature

  4. Development of an enzyme-linked-immunosorbent-assay technique for accurate identification of poorly preserved silks unearthed in ancient tombs.

    Science.gov (United States)

    Zheng, Qin; Wu, Xiaofeng; Zheng, Hailing; Zhou, Yang

    2015-05-01

    We report the preparation of a specific fibroin antibody and its use for the identification of unearthed ancient silk relics. Based on the 12-amino-acid repeat sequence "GAGAGSGAGAGS", which is found in fibroin of the silkworm Bombyx mori, a specific antibody against fibroin was prepared in rabbits through peptide synthesis and carrier-protein coupling. This antibody was highly specific for fibroin found in silk. Using this antibody we have successfully identified four silk samples from different time periods. Our results reveal, for the first time, a method capable of detecting silk from a few milligrams of archaeological fabric that has been buried for thousands of years, confirming that the ancient practice of wearing silk products while praying for rebirth dated back to at least 400 BCE. This method also complements current approaches in silk detection, especially for the characterization of poorly preserved silks, promoting the investigation of silk origins and of ancient clothing cultures.

  5. Morphological and mechanical analysis of electrospun shape memory polymer fibers

    Energy Technology Data Exchange (ETDEWEB)

    Budun, Sinem [Institute of Pure and Applied Science, Marmara University, 34722 Istanbul (Turkey); İşgören, Erkan [Textile Technology, Technical Education Faculty, Marmara University, 34722 Istanbul (Turkey); Erdem, Ramazan, E-mail: ramazanerdem@akdeniz.edu.tr [Textile Technologies, Serik G-S. Sural Vocational School of Higher Education, Akdeniz University, 07500 Antalya (Turkey); Yüksek, Metin [Textile Engineering, Technology Faculty, Marmara University, 34722 Istanbul (Turkey)

    2016-09-01

    Highlights: • Fiber morphology of PU based shape memory fibers varied especially with polymer concentration and applied voltage. • The smallest diameter (381 ± 165 nm) and almost uniform (without bead) fibers were belonged to the sample Y10K30 with a feeding rate of 1 ml/h and an applied voltage of 30 kV at 24.5 cm distance. • All calculated shape fixity results were above 80% and the best value (92 ± 4%) was obtained for Y10K30. • All gained shape recovery results were determined above 100% and the highest measurement (130 ± 4%) was belonged to Y15K39. • The greatest tensile property was obtained for Y10K30 (14.7 ± 3.2 MPa) in machine direction and for Y10K39 (12.9 ± 0.8 MPa) in transverse direction. Y15K39 (411 ± 24%) and Y20K30 (402 ± 34%) possessed the highest elongation results compared with the other electrospun webs. - Abstract: Shape memory block co-polymer Polyurethane (PU) fibers were fabricated by electrospinning technique. Four different solution concentrations (5 wt.%, 10 wt.%, 15 wt.% and 20 wt.%) were prepared by using Tetrahydrofuran (THF)/N,N-dimethylformamide (DMF) (50:50, v/v) as solvents, and three different voltages (30 kV, 35 kV and 38.9 kV) were determined for the electrospinning process. Solution properties were explored in terms of viscosity and electrical conductivity. It was observed that as the polymer concentration increased in the solution, the conductivity declined. Morphological characteristics of the obtained fibers were analyzed through Scanning Electron Microscopy (SEM) measurements. Findings indicated that fiber morphology varied especially with polymer concentration and applied voltage. Obtained fiber diameter ranged from 112 ± 34 nm to 2046 ± 654 nm, respectively. DSC analysis presented that chain orientation of the polymer increased after electrospinning process. Shape fixity and shape recovery calculations were realized. The best shape fixity value (92 ± 4%) was obtained for Y10K30 and the highest shape

  6. Silk Film Topography Directs Collective Epithelial Cell Migration

    Science.gov (United States)

    Rosenblatt, Mark I.

    2012-01-01

    The following study provides new insight into how surface topography dictates directed collective epithelial cell sheet growth through the guidance of individual cell movement. Collective cell behavior of migrating human corneal limbal-epithelial cell sheets were studied on highly biocompatible flat and micro-patterned silk film surfaces. The silk film edge topography guided the migratory direction of individual cells making up the collective epithelial sheet, which resulted in a 75% increase in total culture elongation. This was due to a 3-fold decrease in cell sheet migration rate efficiency for movement perpendicular to the topography edge. Individual cell migration direction is preferred in the parallel approach to the edge topography where localization of cytoskeletal proteins to the topography’s edge region is reduced, which results in the directed growth of the collective epithelial sheet. Findings indicate customized biomaterial surfaces may be created to direct both the migration rate and direction of tissue epithelialization. PMID:23185573

  7. SILK ROAD DISEASE: FROM LEGENDS TO THE 21st CENTURY

    Directory of Open Access Journals (Sweden)

    Z. S. Alekberova

    2015-01-01

    Full Text Available The paper considers the historical and geographical aspects of Behcet’s disease (BD. As is known, the geographical distribution of this disease is associated with the ancient caravan route called the Silk Road: it was in these areas along which the latter once ran there have been predominantly cases of BD so far. There are discrepancies in the literature regarding whether the Silk Road was across the North Caucasus, along the coast of the Caspian Sea in particular. In support of this conjecture, there is interesting evidence: stone-cutting images that have been retained on the houses of the Dagestani settlement of Kubachi. All give an answer why the natives of the North Caucasus constitute one-fourth of the total number of BD patients followed up at the V.A. Nasonova Research Institute of Rheumatology 

  8. Peculiar torsion dynamical response of spider dragline silk

    Science.gov (United States)

    Liu, Dabiao; Yu, Longteng; He, Yuming; Peng, Kai; Liu, Jie; Guan, Juan; Dunstan, D. J.

    2017-07-01

    The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk.

  9. Ultra-high Thermal Conductivity of Spider Silk: Protein Function Study with Controlled Structure Change and Comparison

    Science.gov (United States)

    2016-01-23

    induced increase in energy transport capacity of silkworm silks , Biopolymers , (10 2014): 0. doi: 10.1002/bip.22496 Shen Xu, Zaoli Xu, James Starrett...SECURITY CLASSIFICATION OF: In the past three years, we have conducted extensive research to study the structure of spider silks and investigate how the...manually spun spider silks demonstrates that the alignment of the antiparallel beta-sheet crystals in spider silks plays one of the most important

  10. An Understanding of The Maritime Silk Road International Strategic Importance

    Institute of Scientific and Technical Information of China (English)

    Lin; Hongyu

    2015-01-01

    "The Maritime Silk Road"conception has a very significant international strategic importance,and to China,will certainly play a great role in promoting its economic development,which is only on the surface,and an in-depth reading is that it is a top-level strategic design,whose strategic role with the passage of time will be enlarged.In his address to Indonesian National Assembly in October 2013,President Xi

  11. Silk fibroin gelation via non-solvent induced phase separation

    Czech Academy of Sciences Publication Activity Database

    Kasoju, Naresh; Hawkins, N.; Pop-Georgievski, Ognen; Kubies, Dana; Vollrath, F.

    2016-01-01

    Roč. 4, č. 3 (2016), s. 460-473 ISSN 2047-4830 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : silk fibroin * non-solvent induced phase separation * desolvation Subject RIV: CE - Biochemistry Impact factor: 4.210, year: 2016

  12. Unique molecular architecture of silk fibroin in the waxmoth

    Czech Academy of Sciences Publication Activity Database

    Žurovec, Michal; Sehnal, František

    2002-01-01

    Roč. 277, č. 25 (2002), s. 22639-22647 ISSN 0021-9258 R&D Projects: GA ČR GA204/96/1100; GA ČR GA204/00/0019; GA MŠk ME 204 Institutional research plan: CEZ:AV0Z5007907 Keywords : silk Subject RIV: EG - Zoology Impact factor: 6.696, year: 2002

  13. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    Science.gov (United States)

    Zhang, Yu-Qing; Shen, Wei-De; Xiang, Ru-Li; Zhuge, Lan-Jian; Gao, Wei-Jian; Wang, Wen-Bao

    2007-10-01

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl2, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the ɛ-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and α-helix form (Silk I) into anti-parallel β-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, 13C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with β-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk

  14. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    International Nuclear Information System (INIS)

    Zhang Yuqing; Shen Weide; Xiang Ruli; Zhuge Lanjian; Gao Weijian; Wang Wenbao

    2007-01-01

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl 2 , the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the ε-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and α-helix form (Silk I) into anti-parallel β-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, 13 C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with β-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk

  15. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuqing, E-mail: yqzhang@public1.sz.js.cn; Shen Weide; Xiang Ruli [Soochow University, Silk Biotechnol. Lab., School of Life Science (China); Zhuge Lanjian; Gao Weijian; Wang Wenbao [Soochow University, Analytical Center (China)

    2007-10-15

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into anti-parallel {beta}-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, {sup 13}C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with {beta}-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular

  16. Web building and silk properties functionally covary among species of wolf spider.

    Science.gov (United States)

    Lacava, Mariángeles; Camargo, Arley; Garcia, Luis F; Benamú, Marco A; Santana, Martin; Fang, Jian; Wang, Xungai; Blamires, Sean J

    2018-04-15

    Although phylogenetic studies have shown covariation between the properties of spider major ampullate (MA) silk and web building, both spider webs and silks are highly plastic so we cannot be sure whether these traits functionally covary or just vary across environments that the spiders occupy. As MaSp2-like proteins provide MA silk with greater extensibility, their presence is considered necessary for spider webs to effectively capture prey. Wolf spiders (Lycosidae) are predominantly non-web building, but a select few species build webs. We accordingly collected MA silk from two web-building and six non-web-building species found in semirural ecosystems in Uruguay to test whether the presence of MaSp2-like proteins (indicated by amino acid composition, silk mechanical properties and silk nanostructures) was associated with web building across the group. The web-building and non-web-building species were from disparate subfamilies so we estimated a genetic phylogeny to perform appropriate comparisons. For all of the properties measured, we found differences between web-building and non-web-building species. A phylogenetic regression model confirmed that web building and not phylogenetic inertia influences silk properties. Our study definitively showed an ecological influence over spider silk properties. We expect that the presence of the MaSp2-like proteins and the subsequent nanostructures improves the mechanical performance of silks within the webs. Our study furthers our understanding of spider web and silk co-evolution and the ecological implications of spider silk properties. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

  17. Gel spinning of silk tubes for tissue engineering

    Science.gov (United States)

    Lovett, Michael; Cannizzaro, Christopher; Vunjak-Novakovic, Gordana; Kaplan, David L.

    2011-01-01

    Tubular vessels for tissue engineering are typically fabricated using a molding, dipping, or electrospinning technique. While these techniques provide some control over inner and outer diameters of the tube, they lack the ability to align the polymers or fibers of interest throughout the tube. This is an important aspect of biomaterial composite structure and function for mechanical and biological impact of tissue outcomes. We present a novel aqueous process system to spin tubes from biopolymers and proteins such as silk fibroin. Using silk as an example, this method of winding an aqueous solution around a reciprocating rotating mandrel offers substantial improvement in the control of the tube properties, specifically with regard to winding pattern, tube porosity, and composite features. Silk tube properties are further controlled via different post-spinning processing mechanisms such as methanol-treatment, air-drying, and lyophilization. This approach to tubular scaffold manufacture offers numerous tissue engineering applications such as complex composite biomaterial matrices, blood vessel grafts and nerve guides, among others. PMID:18801570

  18. Silk Fibroin Degradation Related to Rheological and Mechanical Properties.

    Science.gov (United States)

    Partlow, Benjamin P; Tabatabai, A Pasha; Leisk, Gary G; Cebe, Peggy; Blair, Daniel L; Kaplan, David L

    2016-05-01

    Regenerated silk fibroin has been proposed as a material substrate for biomedical, optical, and electronic applications. Preparation of the silk fibroin solution requires extraction (degumming) to remove contaminants, but results in the degradation of the fibroin protein. Here, a mechanism of fibroin degradation is proposed and the molecular weight and polydispersity is characterized as a function of extraction time. Rheological analysis reveals significant changes in the viscosity of samples while mechanical characterization of cast and drawn films shows increased moduli, extensibility, and strength upon drawing. Fifteen minutes extraction time results in degraded fibroin that generates the strongest films. Structural analysis by wide angle X-ray scattering (WAXS) and Fourier transform infrared spectroscopy (FTIR) indicates molecular alignment in the drawn films and shows that the drawing process converts amorphous films into the crystalline, β-sheet, secondary structure. Most interesting, by using selected extraction times, films with near-native crystallinity, alignment, and molecular weight can be achieved; yet maximal mechanical properties for the films from regenerated silk fibroin solutions are found with solutions subjected to some degree of degradation. These results suggest that the regenerated solutions and the film casting and drawing processes introduce more complexity than native spinning processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Fabrication and Mechanical Characterization of Hydrogel Infused Network Silk Scaffolds

    Directory of Open Access Journals (Sweden)

    Lakshminath Kundanati

    2016-09-01

    Full Text Available Development and characterization of porous scaffolds for tissue engineering and regenerative medicine is of great importance. In recent times, silk scaffolds were developed and successfully tested in tissue engineering and drug release applications. We developed a novel composite scaffold by mechanical infusion of silk hydrogel matrix into a highly porous network silk scaffold. The mechanical behaviour of these scaffolds was thoroughly examined for their possible use in load bearing applications. Firstly, unconfined compression experiments show that the denser composite scaffolds displayed significant enhancement in the elastic modulus as compared to either of the components. This effect was examined and further explained with the help of foam mechanics principles. Secondly, results from confined compression experiments that resemble loading of cartilage in confinement, showed nonlinear material responses for all scaffolds. Finally, the confined creep experiments were performed to calculate the hydraulic permeability of the scaffolds using soil mechanics principles. Our results show that composite scaffolds with some modifications can be a potential candidate for use of cartilage like applications. We hope such approaches help in developing novel scaffolds for tissue engineering by providing an understanding of the mechanics and can further be used to develop graded scaffolds by targeted infusion in specific regions.

  20. Study on antibacterial activity of hydrogel from irradiated silk protein

    International Nuclear Information System (INIS)

    Bunnak, J.; Chaisupakitsin, M.

    2001-01-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N 2 atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  1. Structural Analysis of Hand Drawn Bumblebee Bombus terrestris Silk

    Directory of Open Access Journals (Sweden)

    Andrea L. Woodhead

    2016-07-01

    Full Text Available Bombus terrestris, commonly known as the buff-tailed bumblebee, is native to Europe, parts of Africa and Asia. It is commercially bred for use as a pollinator of greenhouse crops. Larvae pupate within a silken cocoon that they construct from proteins produced in modified salivary glands. The amino acid composition and protein structure of hand drawn B. terrestris, silk fibres was investigated through the use of micro-Raman spectroscopy. Spectra were obtained from single fibres drawn from the larvae salivary gland at a rate of 0.14 cm/s. Raman spectroscopy enabled the identification of poly(alanine, poly(alanine-glycine, phenylalanine, tryptophan, and methionine, which is consistent with the results of amino acid analysis. The dominant protein conformation was found to be coiled coil (73% while the β-sheet content of 10% is, as expected, lower than those reported for hornets and ants. Polarized Raman spectra revealed that the coiled coils were highly aligned along the fibre axis while the β-sheet and random coil components had their peptide carbonyl groups roughly perpendicular to the fibre axis. The protein orientation distribution is compared to those of other natural and recombinant silks. A structural model for the B. terrestris silk fibre is proposed based on these results.

  2. Anisotropic silk fibroin/gelatin scaffolds from unidirectional freezing

    Energy Technology Data Exchange (ETDEWEB)

    Asuncion, Maria Christine Tankeh, E-mail: christine.asuncion@u.nus.edu [National University of Singapore, Department of Biomedical Engineering (Singapore); Goh, James Cho-Hong [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Orthopedic Surgery (Singapore); Toh, Siew-Lok [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Mechanical Engineering (Singapore)

    2016-10-01

    Recent studies have underlined the importance of matching scaffold properties to the biological milieu. Tissue, and thus scaffold, anisotropy is one such property that is important yet sometimes overlooked. Methods that have been used to achieve anisotropic scaffolds present challenges such as complicated fabrication steps, harsh processing conditions and toxic chemicals involved. In this study, unidirectional freezing was employed to fabricate anisotropic silk fibroin/gelatin scaffolds in a simple and mild manner. Morphological, mechanical, chemical and cellular compatibility properties were investigated, as well as the effect of the addition of gelatin to certain properties of the scaffold. It was shown that scaffold properties were suitable for cell proliferation and that mesenchymal stem cells were able to align themselves along the directed fibers. The fabricated scaffolds present a platform that can be used for anisotropic tissue engineering applications such as cardiac patches. - Highlights: • Silk/gelatin scaffolds with unidirectional alignment were fabricated using a simple and scalable process • Presence of gelatin in silk resulted to lesser shrinkage, better water retention and improved cell proliferation. • Mesenchymal stem cells were shown to align themselves according to the fiber alignment.

  3. Proteome identification of the silkworm middle silk gland

    Directory of Open Access Journals (Sweden)

    Jian-ying Li

    2016-03-01

    Full Text Available To investigate the functional differentiation among the anterior (A, middle (M, and posterior (P regions of silkworm middle silk gland (MSG, their proteomes were characterized by shotgun LC–MS/MS analysis with a LTQ-Orbitrap mass spectrometer. To get better proteome identification and quantification, triplicate replicates of mass spectrometry analysis were performed for each sample. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (Vizcaíno et al., 2014 [1] via the PRIDE partner repository (Vizcaino, 2013 [2] with the dataset identifier http://www.ebi.ac.uk/pride/archive/projects/PXD003371. The peptide identifications that were further processed by PeptideProphet program in Trans-Proteomic Pipeline (TPP after database search with Mascot software were also available in .XML format files. Data presented here are related to a research article published in Journal of Proteomics by Li et al. (2015 [3]. Keywords: Bombyx mori, Middle silk gland, Silk protein synthesis, Shotgun proteomics, Label-free

  4. Interfacial Shear Strength and Adhesive Behavior of Silk Ionomer Surfaces.

    Science.gov (United States)

    Kim, Sunghan; Geryak, Ren D; Zhang, Shuaidi; Ma, Ruilong; Calabrese, Rossella; Kaplan, David L; Tsukruk, Vladimir V

    2017-09-11

    The interfacial shear strength between different layers in multilayered structures of layer-by-layer (LbL) microcapsules is a crucial mechanical property to ensure their robustness. In this work, we investigated the interfacial shear strength of modified silk fibroin ionomers utilized in LbL shells, an ionic-cationic pair with complementary ionic pairing, (SF)-poly-l-glutamic acid (Glu) and SF-poly-l-lysine (Lys), and a complementary pair with partially screened Coulombic interactions due to the presence of poly(ethylene glycol) (PEG) segments and SF-Glu/SF-Lys[PEG] pair. Shearing and adhesive behavior between these silk ionomer surfaces in the swollen state were probed at different spatial scales and pressure ranges by using functionalized atomic force microscopy (AFM) tips as well as functionalized colloidal probes. The results show that both approaches were consistent in analyzing the interfacial shear strength of LbL silk ionomers at different spatial scales from a nanoscale to a fraction of a micron. Surprisingly, the interfacial shear strength between SF-Glu and SF-Lys[PEG] pair with partially screened ionic pairing was greater than the interfacial shear strength of the SF-Glu and SF-Lys pair with a high density of complementary ionic groups. The difference in interfacial shear strength and adhesive strength is suggested to be predominantly facilitated by the interlayer hydrogen bonding of complementary amino acids and overlap of highly swollen PEG segments.

  5. Processing Techniques and Applications of Silk Hydrogels in Bioengineering

    Directory of Open Access Journals (Sweden)

    Michael Floren

    2016-09-01

    Full Text Available Hydrogels are an attractive class of tunable material platforms that, combined with their structural and functional likeness to biological environments, have a diversity of applications in bioengineering. Several polymers, natural and synthetic, can be used, the material selection being based on the required functional characteristics of the prepared hydrogels. Silk fibroin (SF is an attractive natural polymer for its excellent processability, biocompatibility, controlled degradation, mechanical properties and tunable formats and a good candidate for the fabrication of hydrogels. Tremendous effort has been made to control the structural and functional characteristic of silk hydrogels, integrating novel biological features with advanced processing techniques, to develop the next generation of functional SF hydrogels. Here, we review the several processing methods developed to prepare advanced SF hydrogel formats, emphasizing a bottom-up approach beginning with critical structural characteristics of silk proteins and their behavior under specific gelation environments. Additionally, the preparation of SF hydrogel blends and other advanced formats will also be discussed. We conclude with a brief description of the attractive utility of SF hydrogels in relevant bioengineering applications.

  6. Study on antibacterial activity of hydrogel from irradiated silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Bunnak, J; Chaisupakitsin, M [King Mongkut' s Institute of Technology Lardkrabang, Bangkok (Thailand)

    2001-03-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N{sub 2} atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  7. Exploring the mechanism of microarteriogenesis in porous silk fibroin film.

    Science.gov (United States)

    Bai, Lun; Wang, Guangqian; Tan, Xiaoyan; Xu, Jianmei

    2012-01-01

    Purpose. Based on the experiment of the microarteriogenesis that is associated with angiogenesis during tissue repair process in porous silk fibroin films (PSFFs), we investigate the characteristics of micro-arteriogenesis and explore its mechanism. Methods. After the porous silk fibroin materials are implanted into the back hypodermal tissue of SD rats, the arteriole development and the morphogenesis of smooth muscle cell are histologically monitored and the micro-arteriogenesis is quantitatively analyzed. Results. 10 days after implantation, the arteriole density reaches the highest level in the junction of silk fibroin materials with tissues. Three weeks later, the arteriolar density in the materials reaches the maximum, and the arterioles in the junction of materials with tissues appear to be in a mature and upgrading state. Modeling of Microarteriogenesis. The arterioles in materials are generated after capillary angiogenesis. It is inferred that arteriolar development does not start until the network of the capillaries is formed. At first, the arterioles grow in the conjunct area of precapillaries with arterioles. Then with the extension of the arterioles, the upgrade of arterioles in connecting area is observed at a later stage. Based on the observation, the conditions and the mechanism of microarterializations as well as the upgrade of arterioles are analyzed.

  8. The quintuple-shape memory effect in electrospun nanofiber membranes

    Science.gov (United States)

    Zhang, Fenghua; Zhang, Zhichun; Liu, Yanju; Lu, Haibao; Leng, Jinsong

    2013-08-01

    Shape memory fibrous membranes (SMFMs) are an emerging class of active polymers, which are capable of switching from a temporary shape to their permanent shape upon appropriate stimulation. Quintuple-shape memory membranes based on the thermoplastic polymer Nafion, with a stable fibrous structure, are achieved via electrospinning technology, and possess a broad transition temperature. The recovery of multiple temporary shapes of electrospun membranes can be triggered by heat in a single triple-, quadruple-, quintuple-shape memory cycle, respectively. The fiber morphology and nanometer size provide unprecedented design flexibility for the adjustable morphing effect. SMFMs enable complex deformations at need, having a wide potential application field including smart textiles, artificial intelligence robots, bio-medical engineering, aerospace technologies, etc in the future.

  9. Electrospun nanocomposite fibrous polymer electrolyte for secondary lithium battery applications

    International Nuclear Information System (INIS)

    Padmaraj, O.; Rao, B. Nageswara; Jena, Paramananda; Satyanarayana, N.; Venkateswarlu, M.

    2014-01-01

    Hybrid nanocomposite [poly(vinylidene fluoride -co- hexafluoropropylene) (PVdF-co-HFP)/magnesium aluminate (MgAl 2 O 4 )] fibrous polymer membranes were prepared by electrospinning method. The prepared pure and nanocomposite fibrous polymer electrolyte membranes were soaked into the liquid electrolyte 1M LiPF 6 in EC: DEC (1:1,v/v). XRD and SEM are used to study the structural and morphological studies of nanocomposite electrospun fibrous polymer membranes. The nanocomposite fibrous polymer electrolyte membrane with 5 wt.% of MgAl 2 O 4 exhibits high ionic conductivity of 2.80 × 10 −3 S/cm at room temperature. The charge-discharge capacity of Li/LiCoO 2 coin cells composed of the newly prepared nanocomposite [(16 wt.%) PVdF-co-HFP+(5 wt.%) MgAl 2 O 4 ] fibrous polymer electrolyte membrane was also studied and compared with commercial Celgard separator

  10. Quasi one dimensional transport in individual electrospun composite nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Avnon, A., E-mail: avnon@phys.fu-berlin.de; Datsyuk, V.; Trotsenko, S. [Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Wang, B.; Zhou, S. [Research Center of Microperipheric Technologies, Technische Universität Berlin, TiB4/2-1, Gustav-Meyer-Allee 25, 13355 Berlin (Germany); Grabbert, N.; Ngo, H.-D. [Microsystem Engineering (FB I), University of Applied Sciences, Wilhelminenhofstr. 74 (C 525), 12459 Berlin (Germany)

    2014-01-15

    We present results of transport measurements of individual suspended electrospun nanofibers Poly(methyl methacrylate)-multiwalled carbon nanotubes. The nanofiber is comprised of highly aligned consecutive multiwalled carbon nanotubes. We have confirmed that at the range temperature from room temperature down to ∼60 K, the conductance behaves as power-law of temperature with an exponent of α ∼ 2.9−10.2. The current also behaves as power law of voltage with an exponent of β ∼ 2.3−8.6. The power-law behavior is a footprint for one dimensional transport. The possible models of this confined system are discussed. Using the model of Luttinger liquid states in series, we calculated the exponent for tunneling into the bulk of a single multiwalled carbon nanotube α{sub bulk} ∼ 0.06 which agrees with theoretical predictions.

  11. Electrospun composites of PHBV/pearl powder for bone repairing

    Directory of Open Access Journals (Sweden)

    Jingjing Bai

    2015-08-01

    Full Text Available Electrospun fiber has highly structural similarity with natural bone extracelluar matrix (ECM. Many researches about fabricating organic–inorganic composite materials have been carried out in order to mimic the natural composition of bone and enhance the biocompatibility of materials. In this work, pearl powder was added to the poly (3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV and the composite nanofiber scaffold was prepared by electrospinning. Mineralization ability of the composite scaffolds can be evaluated by analyzing hydroxyapatite (HA formation on the surface of nanofiber scaffolds. The obtained composite nanofiber scaffolds showed an enhanced mineralization capacity due to incorporation of pearl powder. The HA formed amount of the composite scaffolds was raised as the increase of pearl powder in composite scaffolds. Therefore, the prepared PHBV/pearl composite nanofiber scaffolds would be a promising candidate as an osteoconductive composite material for bone repairing.

  12. Hybrid electrospun chitosan-phospholipids nanofibers for transdermal drug delivery

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Gorzelanny, Christian; Halter, Natalia

    2016-01-01

    Chitosan (Ch) polysaccharide was mixed with phospholipids (P) to generate electrospun hybrid nanofibers intended to be used as platforms for transdermal drug delivery. Ch/P nanofibers exibithed average diameters ranging from 248 +/- 94 nm to 600 +/- 201 nm, depending on the amount of phospholipids...... used. Fourier Transformed Infra-Red (FTIR) spectroscopy and Dynamic Light Scattering (DLS) data suggested the occurrence of electrostatic interactions between amine groups of chitosan with the phospholipid counterparts. The nanofibers were shown to be stable for at least 7 days in Phosphate Buffer...... culture plate (control). The release of curcumin, diclofenac and vitamin B12, as model drugs, from Ch/P hybrid nanofibers was investigated, demonstrating their potential utilization as a transdermal drug delivery system....

  13. Electrospun nanofibers: New generation materials for advanced applications

    Energy Technology Data Exchange (ETDEWEB)

    Thenmozhi, S. [Inorganic & Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641 046 (India); DRDO-BU CLS, Bharathiar University Campus, Coimbatore 641 046 (India); Dharmaraj, N., E-mail: dharmaraj@buc.edu.in [Inorganic & Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641 046 (India); Kadirvelu, K. [DRDO-BU CLS, Bharathiar University Campus, Coimbatore 641 046 (India); Kim, Hak Yong [Department of Textile Engineering, Chonbuk National University, Chonju 561-756 (Korea, Republic of)

    2017-03-15

    Highlights: • A review covering important aspects of electrospinning technique is presented. • Applications of nanofibers in various fields are reviewed. • Possibility to up-scale electrospinning technique to industry also included. - Abstract: Electrospinning (E-spin) is a unique technique to fabricate polymeric as well as metal oxide nanofibers. Research on electrospun nanofibers is a very active field in material science owing to their novel applications in diverse domains. The main focus of this review is to provide an insight into E-spin technique by understanding the working principle, influencing parameters and applications of nanofibers in different walks of life. Several hundreds of papers are published on the preparation, modification and applications of nanofibers produced by E-spin technique in the areas like sensor development, decontamination, energy storage, biomedical and catalysis etc. Details on the industrial scale development of E-spin technique, current scenario and future developments are also covered in this review.

  14. Encapsulation of bacteria and viruses in electrospun nanofibres

    International Nuclear Information System (INIS)

    Salalha, W; Kuhn, J; Dror, Y; Zussman, E

    2006-01-01

    Bacteria and viruses were encapsulated in electrospun polymer nanofibres. The bacteria and viruses were suspended in a solution of poly(vinyl alcohol) (PVA) in water and subjected to an electrostatic field of the order of 1 kV cm -1 . Encapsulated bacteria in this work (Escherichia coli, Staphylococcus albus) and bacterial viruses (T7, T4, λ) managed to survive the electrospinning process while maintaining their viability at fairly high levels. Subsequently the bacteria and viruses remain viable during three months at -20 and -55 deg. C without a further decrease in number. The present results demonstrate the potential of the electrospinning process for the encapsulation and immobilization of living biological material

  15. Oxidative stability of pullulan electrospun fibers containing fish oil

    DEFF Research Database (Denmark)

    García Moreno, Pedro Jesús; Damberg, Cecilie; Chronakis, Ioannis S.

    2017-01-01

    The effect of oil content and addition of natural antioxidants on the morphology and oxidative stability of pullulan ultra-thin fibers loaded with fish oil and obtained by electrospinning was investigated. Pullulan sub-micron fibers containing 10 and 30wt% fish oil were prepared and both presented...... into food matrices. These results show the feasibility to encapsulate fish oil in pullulan ultra-thin fibers and to improve their oxidative stability by adding natural antioxidants such as δ-tocopherol and rosemary extract. Therefore, this study might open up new opportunities for further technological...... development in the production of omega-3 nanodelivery systems, which have potential applications in different types of fortified foods. Encapsulation of fish oil in electrospun pullulan fibers stabilized by natural antioxidants....

  16. The quintuple-shape memory effect in electrospun nanofiber membranes

    International Nuclear Information System (INIS)

    Zhang, Fenghua; Zhang, Zhichun; Lu, Haibao; Leng, Jinsong; Liu, Yanju

    2013-01-01

    Shape memory fibrous membranes (SMFMs) are an emerging class of active polymers, which are capable of switching from a temporary shape to their permanent shape upon appropriate stimulation. Quintuple-shape memory membranes based on the thermoplastic polymer Nafion, with a stable fibrous structure, are achieved via electrospinning technology, and possess a broad transition temperature. The recovery of multiple temporary shapes of electrospun membranes can be triggered by heat in a single triple-, quadruple-, quintuple-shape memory cycle, respectively. The fiber morphology and nanometer size provide unprecedented design flexibility for the adjustable morphing effect. SMFMs enable complex deformations at need, having a wide potential application field including smart textiles, artificial intelligence robots, bio-medical engineering, aerospace technologies, etc in the future. (paper)

  17. Electrospun fiber surface nanotopography influences astrocyte-mediated neurite outgrowth.

    Science.gov (United States)

    Johnson, Christopher D; D'Amato, Anthony R; Puhl, Devan L; Wich, Douglas M; Vespermann, Amanda; Gilbert, Ryan J

    2018-05-15

    Aligned, electrospun fiber scaffolds provide topographical guidance for regenerating neurons and glia after central nervous system injury. To date, no study has explored how fiber surface nanotopography affects astrocyte response to fibrous scaffolds. Astrocytes play important roles in the glial scar, the blood brain barrier, and in maintaining homeostasis in the central nervous system. In this study, electrospun poly L-lactic acid fibers were engineered with smooth, pitted, or divoted surface nanotopography. Cortical or spinal cord primary rat astrocytes were cultured on the surfaces for either 1 or 3 days to examine the astrocyte response over time. The results showed that cortical astrocytes were significantly shorter and broader on the pitted and divoted fibers compared to those on smooth fibers. However, spinal cord astrocyte morphology was not significantly altered by the surface features. These findings indicate that astrocytes from unique anatomical locations respond differently to the presence of nanotopography. Western Blot results show that the differences in morphology were not associated with significant changes in GFAP or vinculin in either astrocyte population, suggesting that surface pits and divots do not induce a reactive phenotype in either cortical or spinal cord astrocytes. Finally, astrocytes were co-cultured with dorsal root ganglia to determine how the surfaces affected astrocyte-mediated neurite outgrowth. Astrocytes cultured on the fibers for shorter periods of time (1 day) generally supported longer neurite outgrowth. Pitted and divoted fibers restricted spinal cord astrocyte-mediated neurite outgrowth, while smooth fibers increased 3 day spinal cord astrocyte-mediated neurite outgrowth. In total, fiber surface nanotopography can influence astrocyte elongation and influence the capability of astrocytes to direct neurites. Therefore, fiber surface characteristics should be carefully controlled to optimize astrocyte-mediated axonal

  18. Antimicrobial electrospun silver-, copper- and zinc-doped polyvinylpyrrolidone nanofibers

    International Nuclear Information System (INIS)

    Quirós, Jennifer; Borges, João P.; Boltes, Karina; Rodea-Palomares, Ismael; Rosal, Roberto

    2015-01-01

    Highlights: • Electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc. • Antimicrobial effect for the bacteria Staphylococcus aureus and Escherichia coli. • Silver strongly reduced colony forming units and bacterial viability. • Silver, copper, and zinc led to a significant increase of non-viable cells on mats. - Abstract: The use of electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc nanoparticles was studied to prepare antimicrobial mats using silver and copper nitrates and zinc acetate as precursors. Silver became reduced during electrospinning and formed nanoparticles of several tens of nanometers. Silver nanoparticles and the insoluble forms of copper and zinc were dispersed using low molecular weight PVP as capping agent. High molecular weight PVP formed uniform fibers with a narrow distribution of diameters around 500 nm. The fibers were converted into an insoluble network using ultraviolet irradiation crosslinking. The efficiency of metal-loaded mats against the bacteria Escherichia coli and Staphylococcus aureus was tested for different metal loadings by measuring the inhibition of colony forming units and the staining with fluorescent probes for metabolic viability and compromised membranes. The assays included the culture in contact with mats and the direct staining of surface attached microorganisms. The results indicated a strong inhibition for silver-loaded fibers and the absence of significant amounts of viable but non-culturable microorganisms. Copper and zinc-loaded mats also decreased the metabolic activity and cell viability, although in a lesser extent. Metal-loaded fibers allowed the slow release of the soluble forms of the three metals.

  19. In vitro evaluation of crosslinked electrospun fish gelatin scaffolds

    International Nuclear Information System (INIS)

    Gomes, S.R.; Rodrigues, G.; Martins, G.G.; Henriques, C.M.R.; Silva, J.C.

    2013-01-01

    Gelatin from cold water fish skin was electrospun, crosslinked and investigated as a substrate for the adhesion and proliferation of cells. Gelatin was first dissolved in either water or concentrated acetic acid and both solutions were successfully electrospun. Cross-linking was achieved via three different routes: glutaraldehyde vapor, genipin and dehydrothermal treatment. Solution's properties (surface tension, electrical conductivity and viscosity) and scaffold's properties (chemical bonds, weight loss and fiber diameters) were measured. Cellular viability was analyzed culturing 3T3 fibroblasts plated on the scaffolds and grown up to 7 days. The cells were fixed and observed with SEM or stained for DNA and F-actin and observed with confocal microscopy. In all scaffolds, the cells attached and spread with varying degrees. The evaluation of cell viability showed proliferation of cells until confluence in scaffolds crosslinked by glutaraldehyde and genipin; however the rate of growth in genipin crosslinked scaffolds was slow, recovering only by day five. The results using the dehydrothermal treatment were the less satisfactory. Our results show that glutaraldehyde treated fish gelatin is the most suitable substrate, of the three studied, for fibroblast adhesion and proliferation. - Highlights: ► Electrospinning of fish gelatin dissolved in both water or concentrated acetic acid ► Glutaraldehyde, genipin and dehydrothermal treatment effectively crosslink the fish gelatin fibers ► Fibroblasts effectively adhere to and propagate on all scaffolds ► Cell population is highest for glutaraldehyde crosslinked scaffolds ► Cells exhibit more filopodia and stress fibers on glutaraldehyde crosslinked scaffolds

  20. In vitro evaluation of crosslinked electrospun fish gelatin scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, S.R. [Centro de Física e Investigação Tecnológica / Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Rodrigues, G.; Martins, G.G. [Centro de Biologia Ambiental / Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, FCUL, 1749-016 Campo Grande, Lisboa (Portugal); Henriques, C.M.R. [Centro de Física e Investigação Tecnológica / Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Silva, J.C., E-mail: jcs@fct.unl.pt [Centro de Física e Investigação Tecnológica / Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2013-04-01

    Gelatin from cold water fish skin was electrospun, crosslinked and investigated as a substrate for the adhesion and proliferation of cells. Gelatin was first dissolved in either water or concentrated acetic acid and both solutions were successfully electrospun. Cross-linking was achieved via three different routes: glutaraldehyde vapor, genipin and dehydrothermal treatment. Solution's properties (surface tension, electrical conductivity and viscosity) and scaffold's properties (chemical bonds, weight loss and fiber diameters) were measured. Cellular viability was analyzed culturing 3T3 fibroblasts plated on the scaffolds and grown up to 7 days. The cells were fixed and observed with SEM or stained for DNA and F-actin and observed with confocal microscopy. In all scaffolds, the cells attached and spread with varying degrees. The evaluation of cell viability showed proliferation of cells until confluence in scaffolds crosslinked by glutaraldehyde and genipin; however the rate of growth in genipin crosslinked scaffolds was slow, recovering only by day five. The results using the dehydrothermal treatment were the less satisfactory. Our results show that glutaraldehyde treated fish gelatin is the most suitable substrate, of the three studied, for fibroblast adhesion and proliferation. - Highlights: ► Electrospinning of fish gelatin dissolved in both water or concentrated acetic acid ► Glutaraldehyde, genipin and dehydrothermal treatment effectively crosslink the fish gelatin fibers ► Fibroblasts effectively adhere to and propagate on all scaffolds ► Cell population is highest for glutaraldehyde crosslinked scaffolds ► Cells exhibit more filopodia and stress fibers on glutaraldehyde crosslinked scaffolds.

  1. Antimicrobial electrospun silver-, copper- and zinc-doped polyvinylpyrrolidone nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Quirós, Jennifer [Department of Chemical Engineering, University of Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Borges, João P. [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Boltes, Karina [Department of Chemical Engineering, University of Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Madrid Institute for Advanced Studies of Water (IMDEA Agua), Parque Científico Tecnológico, E-28805, Alcalá de Henares, Madrid (Spain); Rodea-Palomares, Ismael [Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Rosal, Roberto [Department of Chemical Engineering, University of Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Madrid Institute for Advanced Studies of Water (IMDEA Agua), Parque Científico Tecnológico, E-28805, Alcalá de Henares, Madrid (Spain)

    2015-12-15

    Highlights: • Electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc. • Antimicrobial effect for the bacteria Staphylococcus aureus and Escherichia coli. • Silver strongly reduced colony forming units and bacterial viability. • Silver, copper, and zinc led to a significant increase of non-viable cells on mats. - Abstract: The use of electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc nanoparticles was studied to prepare antimicrobial mats using silver and copper nitrates and zinc acetate as precursors. Silver became reduced during electrospinning and formed nanoparticles of several tens of nanometers. Silver nanoparticles and the insoluble forms of copper and zinc were dispersed using low molecular weight PVP as capping agent. High molecular weight PVP formed uniform fibers with a narrow distribution of diameters around 500 nm. The fibers were converted into an insoluble network using ultraviolet irradiation crosslinking. The efficiency of metal-loaded mats against the bacteria Escherichia coli and Staphylococcus aureus was tested for different metal loadings by measuring the inhibition of colony forming units and the staining with fluorescent probes for metabolic viability and compromised membranes. The assays included the culture in contact with mats and the direct staining of surface attached microorganisms. The results indicated a strong inhibition for silver-loaded fibers and the absence of significant amounts of viable but non-culturable microorganisms. Copper and zinc-loaded mats also decreased the metabolic activity and cell viability, although in a lesser extent. Metal-loaded fibers allowed the slow release of the soluble forms of the three metals.

  2. Microporous dermal-like electrospun scaffolds promote accelerated skin regeneration.

    Science.gov (United States)

    Bonvallet, Paul P; Culpepper, Bonnie K; Bain, Jennifer L; Schultz, Matthew J; Thomas, Steven J; Bellis, Susan L

    2014-09-01

    The goal of this study was to synthesize skin substitutes that blend native extracellular matrix (ECM) molecules with synthetic polymers which have favorable mechanical properties. To this end, scaffolds were electrospun from collagen I (col) and poly(ɛ-caprolactone) (PCL), and then pores were introduced mechanically to promote fibroblast infiltration, and subsequent filling of the pores with ECM. A 70:30 col/PCL ratio was determined to provide optimal support for dermal fibroblast growth, and a pore diameter, 160 μm, was identified that enabled fibroblasts to infiltrate and fill pores with native matrix molecules, including fibronectin and collagen I. Mechanical testing of 70:30 col/PCL scaffolds with 160 μm pores revealed a tensile strength of 1.4 MPa, and the scaffolds also exhibited a low rate of contraction (pores. Keratinocytes formed a stratified layer on the surface of fibroblast-remodeled scaffolds, and staining for cytokeratin 10 revealed terminally differentiated keratinocytes at the apical surface. When implanted, 70:30 col/PCL scaffolds degraded within 3-4 weeks, an optimal time frame for degradation in vivo. Finally, 70:30 col/PCL scaffolds with or without 160 μm pores were implanted into full-thickness critical-sized skin defects. Relative to nonporous scaffolds or sham wounds, scaffolds with 160 μm pores induced accelerated wound closure, and stimulated regeneration of healthy dermal tissue, evidenced by a more normal-appearing matrix architecture, blood vessel in-growth, and hair follicle development. Collectively, these results suggest that microporous electrospun scaffolds are effective substrates for skin regeneration.

  3. Optimization of the silk scaffold sericin removal process for retention of silk fibroin protein structure and mechanical properties

    International Nuclear Information System (INIS)

    Teh, Thomas K H; Toh, Siew-Lok; Goh, James C H

    2010-01-01

    In the process of removing sericin (degumming) from a raw silk scaffold, the fibroin structural integrity is often challenged, leading to mechanical depreciation. This study aims to identify the factors and conditions contributing to fibroin degradation during alkaline degumming and to perform an optimization study of the parameters involved to achieve preservation of fibroin structure and properties. The methodology involves degumming knitted silk scaffolds for various durations (5-90 min) and temperatures (60-100 0 C). Mechanical agitation and use of the refreshed solution during degumming are included to investigate how these factors contribute to degumming efficiency and fibroin preservation. Characterizations of silk fibroin morphology, mechanical properties and protein components are determined by scanning electron microscopy (SEM), single fiber tensile tests and gel electrophoresis (SDS-PAGE), respectively. Sericin removal is ascertained via SEM imaging and a protein fractionation method involving SDS-PAGE. The results show that fibroin fibrillation, leading to reduced mechanical integrity, is mainly caused by prolonged degumming duration. Through a series of optimization, knitted scaffolds are observed to be optimally degummed and experience negligible mechanical and structural degradation when subjected to alkaline degumming with mechanical agitation for 30 min at 100 0 C.

  4. Folding behavior of four silks of giant honey bee reflects the evolutionary conservation of aculeate silk proteins.

    Science.gov (United States)

    Maitip, Jakkrawut; Trueman, Holly E; Kaehler, Benjamin D; Huttley, Gavin A; Chantawannakul, Panuwan; Sutherland, Tara D

    2015-04-01

    Multiple gene duplication events in the precursor of the Aculeata (bees, ants, hornets) gave rise to four silk genes. Whilst these homologs encode proteins with similar amino acid composition and coiled coil structure, the retention of all four homologs implies they each are important. In this study we identified, produced and characterized the four silk proteins from Apis dorsata, the giant Asian honeybee. The proteins were readily purified, allowing us to investigate the folding behavior of solutions of individual proteins in comparison to mixtures of all four proteins at concentrations where they assemble into their native coiled coil structure. In contrast to solutions of any one protein type, solutions of a mixture of the four proteins formed coiled coils that were stable against dilution and detergent denaturation. The results are consistent with the formation of a heteromeric coiled coil protein complex. The mechanism of silk protein coiled coil formation and evolution is discussed in light of these results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Preparation of Porous Scaffolds from Silk Fibroin Extracted from the Silk Gland of Bombyx mori (B. mori

    Directory of Open Access Journals (Sweden)

    Liangjun Zhu

    2012-06-01

    Full Text Available In order to use a simple and ecofriendly method to prepare porous silk scaffolds, aqueous silk fibroin solution (ASF was extracted from silk gland of 7-day-old fifth instar larvae of Bombyx mori (B. mori. SDS-page analysis indicated that the obtained fibroin had a molecular weight higher than 200 kDa. The fabrication of porous scaffolds from ASF was achieved by using the freeze-drying method. The pore of porous scaffolds is homogenous and tends to become smaller with an increase in the concentration of ASF. Conversely, the porosity is decreased. The porous scaffolds show impressive compressive strength which can be as high as 6.9 ± 0.4 MPa. Furthermore, ASF has high cell adhesion and growth activity. It also exhibits high ALP activity. This implies that porous scaffolds prepared from ASF have biocompatibility. Therefore, the porous scaffolds prepared in this study have potential application in tissue engineering due to the impressive compressive strength and biocompatibility.

  6. Optimization of the silk scaffold sericin removal process for retention of silk fibroin protein structure and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Teh, Thomas K H; Toh, Siew-Lok; Goh, James C H, E-mail: dosgohj@nus.edu.s, E-mail: dostkh@nus.edu.s, E-mail: bietohsl@nus.edu.s [Division of Bioengineering, National University of Singapore (Singapore)

    2010-06-01

    In the process of removing sericin (degumming) from a raw silk scaffold, the fibroin structural integrity is often challenged, leading to mechanical depreciation. This study aims to identify the factors and conditions contributing to fibroin degradation during alkaline degumming and to perform an optimization study of the parameters involved to achieve preservation of fibroin structure and properties. The methodology involves degumming knitted silk scaffolds for various durations (5-90 min) and temperatures (60-100 {sup 0}C). Mechanical agitation and use of the refreshed solution during degumming are included to investigate how these factors contribute to degumming efficiency and fibroin preservation. Characterizations of silk fibroin morphology, mechanical properties and protein components are determined by scanning electron microscopy (SEM), single fiber tensile tests and gel electrophoresis (SDS-PAGE), respectively. Sericin removal is ascertained via SEM imaging and a protein fractionation method involving SDS-PAGE. The results show that fibroin fibrillation, leading to reduced mechanical integrity, is mainly caused by prolonged degumming duration. Through a series of optimization, knitted scaffolds are observed to be optimally degummed and experience negligible mechanical and structural degradation when subjected to alkaline degumming with mechanical agitation for 30 min at 100 {sup 0}C.

  7. Institutionalizing Chineseness. The legacies of Chinese commercial hegemony in the Cambodian silk industry

    NARCIS (Netherlands)

    Dahles, H.; ter Horst, J.

    2012-01-01

    The Cambodian silk weaving industry shows a remarkable pattern of ethnicised positions interlocked in processes of production and trade stretching beyond Cambodia into the Southeast Asian region and into Europe and the United States. Key commercial positions in the Cambodian silk trading networks

  8. Invited review the coiled coil silk of bees, ants, and hornets.

    Science.gov (United States)

    Sutherland, Tara D; Weisman, Sarah; Walker, Andrew A; Mudie, Stephen T

    2012-06-01

    In this article, we review current knowledge about the silk produced by the larvae of bees, ants, and hornets [Apoidea and Vespoidea: Hymenoptera]. Different species use the silk either alone or in composites for a variety of purposes including mechanical reinforcement, thermal regulation, or humidification. The characteristic molecular structure of this silk is α-helical proteins assembled into tetrameric coiled coils. Gene sequences from seven species are available, and each species possesses a copy of each of four related silk genes that encode proteins predicted to form coiled coils. The proteins are ordered at multiple length scales within the labial gland of the final larval instar before spinning. The insects control the morphology of the silk during spinning to produce either fibers or sheets. The silk proteins are small and non repetitive and have been produced artificially at high levels by fermentation in E. coli. The artificial silk proteins can be fabricated into materials with structural and mechanical properties similar to those of native silks. Copyright © 2011 Wiley Periodicals, Inc.

  9. Mechanical properties of silk of the Australian golden orb weavers Nephila pilipes and Nephilaplumipes.

    Science.gov (United States)

    Kerr, Genevieve G; Nahrung, Helen F; Wiegand, Aaron; Kristoffersen, Joanna; Killen, Peter; Brown, Cameron; Macdonald, Joanne

    2018-02-22

    Silks from orb-weaving spiders are exceptionally tough, producing a model polymer for biomimetic fibre development. The mechanical properties of naturally spun silk threads from two species of Australian orb-weavers, Nephila pilipes and Nephila plumipes , were examined here in relation to overall thread diameter, the size and number of fibres within threads, and spider size. N. pilipes , the larger of the two species, had significantly tougher silk with higher strain capacity than its smaller congener, producing threads with average toughness of 150 MJ m -3 , despite thread diameter, mean fibre diameter and number of fibres per thread not differing significantly between the two species. Within N. pilipes , smaller silk fibres were produced by larger spiders, yielding tougher threads. In contrast, while spider size was correlated with thread diameter in N. plumipes , there were no clear patterns relating to silk toughness, which suggests that the differences in properties between the silk of the two species arise through differing molecular structure. Our results support previous studies that found that the mechanical properties of silk differ between distantly related spider species, and extends on that work to show that the mechanical and physical properties of silk from more closely related species can also differ remarkably. © 2018. Published by The Company of Biologists Ltd.

  10. Feeding Single-Walled Carbon Nanotubes or Graphene to Silkworms for Reinforced Silk Fibers.

    Science.gov (United States)

    Wang, Qi; Wang, Chunya; Zhang, Mingchao; Jian, Muqiang; Zhang, Yingying

    2016-10-12

    Silkworm silk is gaining significant attention from both the textile industry and research society because of its outstanding mechanical properties and lustrous appearance. The possibility of creating tougher silks attracts particular research interest. Carbon nanotubes and graphene are widely studied for their use as reinforcement. In this work, we report mechanically enhanced silk directly collected by feeding Bombyx mori larval silkworms with single-walled carbon nanotubes (SWNTs) and graphene. We found that parts of the fed carbon nanomaterials were incorporated into the as-spun silk fibers, whereas the others went into the excrement of silkworms. Spectroscopy study indicated that nanocarbon additions hindered the conformation transition of silk fibroin from random coil and α-helix to β-sheet, which may contribute to increased elongation at break and toughness modules. We further investigated the pyrolysis of modified silk, and a highly developed graphitic structure with obviously enhanced electrical conductivity was obtained through the introduction of SWNTs and graphene. The successful generation of these SWNT- or graphene-embedded silks by in vivo feeding is expected to open up possibilities for the large-scale production of high-strength silk fibers.

  11. Energy absorption and failure response of silk/epoxy composite square tubes: Experimental

    DEFF Research Database (Denmark)

    Oshkovr, Simin Ataollahi; Taher, Siavash Talebi; A. Eshkoor, Rahim

    2012-01-01

    This paper focuses on natural silk/epoxy composite square tubes energy absorption and failure response. The tested specimens were featured by a material combination of different lengths and same numbers of natural silk/epoxy composite layers in form of reinforced woven fabric in thermosetting epoxy...

  12. Investigation of synthetic spider silk crystallinity and alignment via electrothermal, pyroelectric, literature XRD, and tensile techniques

    NARCIS (Netherlands)

    Munro, Troy; Putzeys, Tristan; Copeland, Cameron G.; Xing, Changhu; Lewis, Randolph V.; Ban, Heng; Glorieux, Christ; Wubbenhorst, Michael

    2017-01-01

    The processes used to create synthetic spider silk greatly affect the properties of the produced fibers. This paper investigates the effect of process variations during artificial spinning on the thermal and mechanical properties of the produced silk. Property values are also compared to the ones of

  13. More than a safety line: jump-stabilizing silk of salticids.

    Science.gov (United States)

    Chen, Yung-Kang; Liao, Chen-Pan; Tsai, Feng-Yueh; Chi, Kai-Jung

    2013-10-06

    Salticids are diurnal hunters known for acute vision, remarkable predatory strategies and jumping ability. Like other jumpers, they strive for stability and smooth landings. Instead of using inertia from swinging appendages or aerodynamic forces by flapping wings as in other organisms, we show that salticids use a different mechanism for in-air stability by using dragline silk, which was previously believed to function solely as a safety line. Analyses from high-speed images of jumps by the salticid Hasarius adansoni demonstrate that despite being subject to rearward pitch at take-off, spiders with dragline silk can change body orientation in the air. Instantaneous drag and silk forces calculated from kinematic data further suggest a comparable contribution to deceleration and energy dissipation, and reveal that adjustments by the spider to the silk force can reverse its body pitch for a predictable and optimal landing. Without silk, upright-landing spiders would slip or even tumble, deferring completion of landing. Thus, for salticids, dragline silk is critical for dynamic stability and prey-capture efficiency. The dynamic functioning of dragline silk revealed in this study can advance the understanding of silk's physiological control over material properties and its significance to spider ecology and evolution, and also provide inspiration for future manoeuvrable robot designs.

  14. A highly divergent gene cluster in honey bees encodes a novel silk family.

    Science.gov (United States)

    Sutherland, Tara D; Campbell, Peter M; Weisman, Sarah; Trueman, Holly E; Sriskantha, Alagacone; Wanjura, Wolfgang J; Haritos, Victoria S

    2006-11-01

    The pupal cocoon of the domesticated silk moth Bombyx mori is the best known and most extensively studied insect silk. It is not widely known that Apis mellifera larvae also produce silk. We have used a combination of genomic and proteomic techniques to identify four honey bee fiber genes (AmelFibroin1-4) and two silk-associated genes (AmelSA1 and 2). The four fiber genes are small, comprise a single exon each, and are clustered on a short genomic region where the open reading frames are GC-rich amid low GC intergenic regions. The genes encode similar proteins that are highly helical and predicted to form unusually tight coiled coils. Despite the similarity in size, structure, and composition of the encoded proteins, the genes have low primary sequence identity. We propose that the four fiber genes have arisen from gene duplication events but have subsequently diverged significantly. The silk-associated genes encode proteins likely to act as a glue (AmelSA1) and involved in silk processing (AmelSA2). Although the silks of honey bees and silkmoths both originate in larval labial glands, the silk proteins are completely different in their primary, secondary, and tertiary structures as well as the genomic arrangement of the genes encoding them. This implies independent evolutionary origins for these functionally related proteins.

  15. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    Directory of Open Access Journals (Sweden)

    Christine Radtke

    2016-10-01

    Full Text Available Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration.

  16. Preparation and characterization of regenerated fiber from the aqueous solution of Bombyx mori cocoon silk fibroin

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhenghua [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Department of Application Engineering, ZheJiang Vocational College of Economic and Trade, HangZhou, ZheJiang 310018 (China); Imada, Takuzo [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Asakura, Tetsuo, E-mail: asakura@cc.tuat.ac.jp [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2009-10-15

    The regenerated silk fibers with high strength and high biodegradability were prepared from the aqueous solution of Bombyx mori silk fibroin from cocoons with wet spinning method. Although the tensile strength of the regenerated silk fibroin fiber, 210 MPa is still half of the strength of native silk fiber, the diameter of the fiber is about 100 {mu}m which is suitable for monofilament of suture together with high biodegradability. The high concentration (30%, w/v) of the aqueous solution of the silk fibroin which corresponds to the high concentration in the middle silkgland of silkworm was obtained. This was performed by adjusting the pH of the aqueous solution to 10.4 which corresponds to pK{sub a} value of the OH group of Tyr residues in the silk fibroin. The mixed solvent, methanol/acetic acid (7:3 in volume ratio) was used as coagulant solvent for preparing the regenerated fiber. The structural change of silk fibroin fiber by stretching was monitored with both {sup 13}C solid state NMR and X-ray diffraction methods, indicating that the high strength of the fiber is related with the long-range orientation of the silk fibroin chain with {beta}-sheet structure.

  17. Timing of autophagy and apoptosis during posterior silk gland degeneration in Bombyx mori.

    Science.gov (United States)

    Montali, Aurora; Romanelli, Davide; Cappellozza, Silvia; Grimaldi, Annalisa; de Eguileor, Magda; Tettamanti, Gianluca

    2017-07-01

    Over the years, the silkworm, Bombyx mori, has been manipulated by means of chemical and genetic approaches to improve silk production both quantitatively and qualitatively. The silk is produced by the silk gland, which degenerates quickly once the larva has finished spinning the cocoon. Thus, interfering with this degeneration process could help develop new technologies aimed at ameliorating silk yield. To this end, in this work we studied the cell death processes that lead to the demise of the posterior silk gland of B. mori, directing in particular our attention to autophagy and apoptosis. We focused on this portion of the gland because it produces fibroin, the main component of the silk thread. By using multiple markers, we provide a morphological, biochemical and molecular characterization of the apoptotic and autophagic processes and define their timing in this biological setting. Our data demonstrate that the activation of both autophagy and apoptosis is preceded by a transcriptional rise in key regulatory genes. Moreover, while autophagy is maintained active for several days and progressively digests silk gland cells, apoptosis is only switched on at a very late stage of silk gland demise. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Highly water-absorbing silk yarn with interpenetrating network via in situ polymerization.

    Science.gov (United States)

    Lee, Ka I; Wang, Xiaowen; Guo, Xia; Yung, Ka-Fu; Fei, Bin

    2017-02-01

    Silk was modified via in situ polymerization of two monomers acrylamide and sodium acrylate by swelling in an effective LiBr dissolution system. Swelling of natural silks in LiBr solutions of low concentration was clearly observed under optical microscope, and their conformational changes were revealed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Dissolution tests and FTIR spectra of these modified silks suggested the presence of interpenetrating network of polyacrylamide and poly(sodium acrylate) in the silk yarns. These modified silks exhibited superior water absorption to that of raw silk and greatly improved mechanical properties in both dry and wet states. These novel modified silks also showed low cytotoxicity towards skin keratinocytes, having potential applications in biomedical textiles. This modification method by in situ polymerization after swelling in LiBr provides a new route to highly enhance the properties and performance of silk for various applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. The protective ability of Camellia meal extract on the silk protein

    Science.gov (United States)

    Weng, JZ; Cai, C.; Zhang, DY; Dai, BK

    2018-02-01

    With the enhancement of living standards, people pay more and more attention to the health. The edible oil become more and more popular, but also produced a large amount of Camellia meal which can not fully put into utilization. In this study, the extracting liquid of Camellia meal was used on the process of silk degumming. Firstly, tussah silk was treated by degumming in the Na2CO3 solution, and the preliminary condition of tussah silk degumming was obtained by orthogonal experiment: the concentration Na2CO3 was 0.1%, the degumming time was 1 hour, and the ratio of silk/water was 40:1. Then the extract of Camellia meal (GCJSY) was added before the bleaching process of tussah silk to investigate the protective ability of GCJSY on the silk protein basry on the residual ratio of the silk. While the concentration of GYJSY was 0.08%, the residual ratio of silk after degumming in the Na2CO3 solution and bleaching in the 2% H2O2 solution was 87.2%.

  20. Study on improving antioxidant and antibacterial activities of silk fibroin by irradiation treatment

    International Nuclear Information System (INIS)

    Tran Bang Diep; Nguyen Van Binh; Hoang Phuong Thao; Hoang Dang Sang; Nguyen Thuy Huong Trang

    2014-01-01

    The silk fibroin solutions were prepared in solvent system of CaCl 2 . CH 3 CH 2 OH. H 2 O (mole ratio = 1:2:8) followed dialysis against deionized water. The 3% silk fibroin solutions were irradiated under gamma Co-60 source with dose ranging from 0 to 50 kGy at Hanoi Irradiation Centre and bioactivities of the irradiated silk fibroin solutions were investigated with different radiation doses. The results indicated that the antioxidant and antibacterial activities of fibroin were much improved by gamma irradiation. Maximum value of DPPH radical scavenging activity was 70.4% for the solution of silk fibroin irradiated at 10 kGy. Silk fibroin solutions irradiated at doses higher than 10 kGy also exhibited rather high antibacterial activity against E. coli and S. aureus. In order to estimate the applicability of our irradiated fibroin, the silk fibroin solutions were lyophilized to obtain a pure fibroin powder, then their bio-activities were compared with those of commercial silk fibroin (Proteines De Soie/ Zijdeproteine, Bioflore, Canada). Our fibroin powder revealed higher antioxidant and antibacterial activities. The amino acid compositions of our irradiated fibroin were also higher than that of the commercial product. Thus, the irradiated silk fibroin can be used for further application in cosmetic and other related fields. (author)

  1. Distinct spinning patterns gain differentiated loading tolerance of silk thread anchorages in spiders with different ecology.

    Science.gov (United States)

    Wolff, Jonas O; van der Meijden, Arie; Herberstein, Marie E

    2017-07-26

    Building behaviour in animals extends biological functions beyond bodies. Many studies have emphasized the role of behavioural programmes, physiology and extrinsic factors for the structure and function of buildings. Structure attachments associated with animal constructions offer yet unrealized research opportunities. Spiders build a variety of one- to three-dimensional structures from silk fibres. The evolution of economic web shapes as a key for ecological success in spiders has been related to the emergence of high performance silks and thread coating glues. However, the role of thread anchorages has been widely neglected in those models. Here, we show that orb-web (Araneidae) and hunting spiders (Sparassidae) use different silk application patterns that determine the structure and robustness of the joint in silk thread anchorages. Silk anchorages of orb-web spiders show a greater robustness against different loading situations, whereas the silk anchorages of hunting spiders have their highest pull-off resistance when loaded parallel to the substrate along the direction of dragline spinning. This suggests that the behavioural 'printing' of silk into attachment discs along with spinneret morphology was a prerequisite for the evolution of extended silk use in a three-dimensional space. This highlights the ecological role of attachments in the evolution of animal architectures. © 2017 The Author(s).

  2. Flexible, highly sensitive pressure sensor with a wide range based on graphene-silk network structure

    Science.gov (United States)

    Liu, Ying; Tao, Lu-Qi; Wang, Dan-Yang; Zhang, Tian-Yu; Yang, Yi; Ren, Tian-Ling

    2017-03-01

    In this paper, a flexible, simple-preparation, and low-cost graphene-silk pressure sensor based on soft silk substrate through thermal reduction was demonstrated. Taking silk as the support body, the device had formed a three-dimensional structure with ordered multi-layer structure. Through a simple and low-cost process technology, graphene-silk pressure sensor can achieve the sensitivity value of 0.4 kPa - 1 , and the measurement range can be as high as 140 kPa. Besides, pressure sensor can have a good combination with knitted clothing and textile product. The signal had good reproducibility in response to different pressures. Furthermore, graphene-silk pressure sensor can not only detect pressure higher than 100 kPa, but also can measure weak body signals. The characteristics of high-sensitivity, good repeatability, flexibility, and comfort for skin provide the high possibility to fit on various wearable electronics.

  3. Research On Degradation Of Silk Fibroin By Combination Of Electron Beam Irradiation And Hydrothermal Processing

    International Nuclear Information System (INIS)

    Nguyen Thi Kim Lan; Dang Van Phu; Le Anh Quoc; Nguyen Quoc Hien

    2014-01-01

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The protein content increased from 0.4617 to 0.6530 mg/mg when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  4. Coating of hydrophobins on three-dimensional electrospun poly(lactic-co-glycolic acid) scaffolds for cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Hou Sen; Li Xinxin; Li Xiaoyu; Feng Xizeng, E-mail: xzfeng@nankai.edu.c [College of Life Science, Nankai University, Weijin Road 94, Tianjin, 300071 (China)

    2009-09-15

    Surface modification with hydrophobins is very important for cell adhesion in its applications in biosensor fabrication. In this study, we modified the surface of three-dimensional electrospun poly(lactide-co-glycolide) (PLGA) scaffolds with hydrophobin HFBI and collagen, and investigated its applications for cell adhesion. We found that HFBI could not only improve the hydrophilicity of the three-dimensional electrospun PLGA scaffolds but also endow the electrospun PLGA scaffolds with water permeability. This permeability should be attributed to both the hydrophilicity of the modified PLGA surface and the large positive capillary effect induced by the microstructures. Further experiment indicated that HFBI modification could improve collagen immobilization on the electrospun PLGA scaffolds and the HFBI/collagen modified electrospun PLGA scaffolds showed higher efficiency in promoting cell adhesion than the native PLGA scaffolds. This finding should be of potential application in biosensor device fabrication.

  5. Morus planting and silk production in Oxus civilization (2000 BC), Transoxiana

    Science.gov (United States)

    Zhou, X.; Li, X.; Wang, J.

    2017-12-01

    Silk is the most important luxury in ancient trade, which promoted communications between east and west civilizations that facilitated the development of them. Currently, probably more than 99% of the silk in commerce in the world today comes from a single species called the silkworm or mulberry silk moth, Bombyx mori (L.), of the family Bombycidae. At present, a list of occurrences of unearthed early silk thread, textile and terracotta figures of China suggests that wild silk has been widely used for weave in Yangtze river and Yellow River basin at least 5000 cal yr BP. On the other hand, the earliest silk fabric out China is from the earliest civilization Harappa site (4500-4000 cal a BP) that confirmed the early use of wild silkworms in South Asia.. In addition, in the Egyptian Deir al Medina relics site, the unearthed silk also as old as nearly 3000 cal a BP, and a serials of pre-han silk also unearthed 3000-2500 cal a BP in Europe. But, the appearance of these out-China silk is usually considered to be the result of the early trade or wild silkmoth products. Here we present a synthesis study of chronology, entomology, protein group, the paleoethnobotany form three Bronze Age site (Sapalli, Jarzgudan, Molleli) concerning on the paleo environment, agriculture gardening, and the possible mulberry silkworm utilization in Bronze Age Tensoxiana 4000 cal a BP. Together with archaeobotany and chronology data from Xinjiang, Hexi corridor and the Loess Plateau in China, we analysis the status of the mulberry silk factory in Bronze Age in Transoxiana and it possible connection to ancient China.

  6. Preparation and characterization of silk fibroin as a biomaterial with potential for drug delivery

    Directory of Open Access Journals (Sweden)

    Zhang Hao

    2012-06-01

    Full Text Available Abstract Background Degummed silk fibroin from Bombyx mori (silkworm has potential carrier capabilities for drug delivery in humans; however, the processing methods have yet to be comparatively analyzed to determine the differential effects on the silk protein properties, including crystalline structure and activity. Methods In this study, we treated degummed silk with four kinds of calcium-alcohol solutions, and performed secondary structure measurements and enzyme activity test to distinguish the differences between the regenerated fibroins and degummed silk fibroin. Results Gel electrophoresis analysis revealed that Ca(NO32-methanol, Ca(NO32-ethanol, or CaCl2-methanol treatments produced more lower molecular weights of silk fibroin than CaCl2-ethanol. X-ray diffraction and Fourier-transform infrared spectroscopy showed that CaCl2-ethanol produced a crystalline structure with more silk I (α-form, type II β-turn, while the other treatments produced more silk II (β-form, anti-parallel β-pleated sheet. Solid-State 13C cross polarization and magic angle spinning-nuclear magnetic resonance measurements suggested that regenerated fibroins from CaCl2-ethanol were nearly identical to degummed silk fibroin, while the other treatments produced fibroins with significantly different chemical shifts. Finally, enzyme activity test indicated that silk fibroins from CaCl2-ethanol had higher activity when linked to a known chemotherapeutic drug, L-asparaginase, than the fibroins from other treatments. Conclusions Collectively, these results suggest that the CaCl2-ethanol processing method produces silk fibroin with biomaterial properties that are appropriate for drug delivery.

  7. Controlled biomineralization of electrospun poly(ε-caprolactone) fibers to enhance their mechanical properties.

    Science.gov (United States)

    Xie, Jingwei; Zhong, Shaoping; Ma, Bing; Shuler, Franklin D; Lim, Chwee Teck

    2013-03-01

    Electrospun polymeric fibers have been investigated as scaffolding materials for bone tissue engineering. However, their mechanical properties, and in particular stiffness and ultimate tensile strength, cannot match those of natural bones. The objective of the study was to develop novel composite nanofiber scaffolds by attaching minerals to polymeric fibers using an adhesive material - the mussel-inspired protein polydopamine - as a "superglue". Herein, we report for the first time the use of dopamine to regulate mineralization of electrospun poly(ε-caprolactone) (PCL) fibers to enhance their mechanical properties. We examined the mineralization of the PCL fibers by adjusting the concentration of HCO(3)(-) and dopamine in the mineralized solution, the reaction time and the surface composition of the fibers. We also examined mineralization on the surface of polydopamine-coated PCL fibers. We demonstrated the control of morphology, grain size and thickness of minerals deposited on the surface of electrospun fibers. The obtained mineral coatings render electrospun fibers with much higher stiffness, ultimate tensile strength and toughness, which could be closer to the mechanical properties of natural bone. Such great enhancement of mechanical properties for electrospun fibers through mussel protein-mediated mineralization has not been seen previously. This study could also be extended to the fabrication of other composite materials to better bridge the interfaces between organic and inorganic phases. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats

    Directory of Open Access Journals (Sweden)

    Chunhui Xiang

    2016-04-01

    Full Text Available Tensile strength, Young’s modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber–fiber load sharing. Single-walled carbon nanotubes (CNTs were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young’s modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber–fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young’s modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young’s modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young’s modulus of the electrospun nylon 6 non-woven fiber mats.

  9. Formation and characterization of magnetic barium ferrite hollow fibers with low coercivity via co-electrospun

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gui-fang, E-mail: guifang777@163.com; Zhang, Zi-dong, E-mail: 1986zzd@163.com; Dang, Feng, E-mail: dangfeng@sdu.edu.cn; Cheng, Chuan-bing, E-mail: 807033063@qq.com; Hou, Chuan-xin, E-mail: 710313782@qq.com; Liu, Si-da, E-mail: superliustar@hotmail.com

    2016-08-15

    BaFe{sub 12}O{sub 19} fibers and hollow fibers were successfully prepared by electrospun and co-electrospun. A very interesting result appeared in this study that hollow fibers made by co-electrospun showed low coercivity values of a few hundred oersteds, compared with the coercivity values of more than thousand oersteds for the fibers made by electrospun. So the hollow fibers with high saturation magnetization (M{sub s}) and while comparatively low coercivity (H{sub c}) exhibited strong magnetism and basically showed soft character. And this character for hollow fibers will lead to increase of the permeability for the samples which is favorable for impedance matching in microwave absorption. So these hollow fibers are promised to have use in a number of applications, such as switching and sensing applications, electromagnetic materials, microwave absorber. - Highlights: • BaFe{sub 12}O{sub 19} fibers were prepared via electrospinning successfully. • The coercivity has a value of a few hundred oersteds for the hollow fibers made by coaxial electrospun. • BaFe{sub 12}O{sub 19} with high saturation magnetization and low coercivity shows great potential in microwave absorbing application.

  10. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Energy Technology Data Exchange (ETDEWEB)

    Gajos, Katarzyna, E-mail: katarzyna.gajos@doctoral.uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Budkowski, Andrzej [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Tsialla, Zoi; Petrou, Panagiota [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Awsiuk, Kamil; Dąbczyński, Paweł [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Bernasik, Andrzej [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Rysz, Jakub [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Misiakos, Konstantinos; Raptis, Ioannis [Department of Microelectronics, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Kakabakos, Sotirios [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece)

    2017-07-15

    Highlights: • Contact pin-printing of overlapping probe spots and spotting by hand are compared. • Contact pin-printing favors probe immobilization with two-fold higher surface density. • Incomplete monolayer develops to bilayer as printing solution concentration increases. • Blocking molecules complete probe monolayer but reduce probe bilayer. • Surface immunoreaction increases with probe concentration in printing solution. - Abstract: Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si{sub 3}N{sub 4}-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si{sub 3}N{sub 4} surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency

  11. Surface biofunctionalization of three-dimensional porous poly(lactic acid) scaffold using chitosan/OGP coating for bone tissue engineering.

    Science.gov (United States)

    Zeng, Sen; Ye, Jianhua; Cui, Zhixiang; Si, Junhui; Wang, Qianting; Wang, Xiaofeng; Peng, Kaiping; Chen, Wenzhe

    2017-08-01

    As one of the stimulators on bone formation, osteogenic growth peptide (OGP) improves both proliferation and differentiation of the bone cells in vitro and in vivo. The aim of this work was the preparation of three dimensional porous poly(lactic acid) (PLA) scaffold with high porosity from PLA-dioxane-water ternary system with the use of vacuum-assisted solvent casting, phase separation, solvent extraction and particle leaching methods. Then, by surface coating of PLA scaffold with chitosan (CS)/OGP solution, biofunctionalization of PLA scaffold had been completed for application in bone regeneration. The effects of frozen temperature (-20, -50, -80°C) and PLA solution concentration (10, 12, 14wt%) on the microstructure, water absorption, porosity, hydrophilicity, mechanical properties, and biocompatibility of PLA and CS/OGP/PLA scaffold were investigated. Results showed that both PLA and CS/OGP/PLA scaffolds have an interconnected network structure and a porosity of up to 96.1% and 91.5%, respectively. The CS/OGP/PLA scaffold exhibited better hydrophilicity and mechanical properties than that of uncoated PLA scaffold. Moreover, the results of cell culture test showed that CS/OGP coating could stimulate the proliferation and growth of osteoblast cells on CS/OGP/PLA scaffold. These finding suggested that the surface biofunctionalization by CS/OGP coating layer could be an effective method on enhancing cell adhesion to synthetic polymer-based scaffolds in tissue engineering application and the developed porous CS/OGP/PLA scaffold should be considered as alternative biomaterials for bone regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Acylation Modification of Antheraea pernyi Silk Fibroin Using Succinic Anhydride and Its Effects on Enzymatic Degradation Behavior

    Directory of Open Access Journals (Sweden)

    Xiufang Li

    2013-01-01

    Full Text Available The degradation rate of tissue engineering scaffolds should match the regeneration rate of new tissues. Controlling the degradation behavior of silk fibroin is an important subject for silk-based tissue engineering scaffolds. In this study, Antheraea pernyi silk fibroin was successfully modified with succinic anhydride and then characterized by zeta potential, ninhydrin method, and FTIR. In vitro, three-dimensional scaffolds prepared with modified silk fibroin were incubated in collagenase IA solution for 18 days to evaluate the impact of acylation on the degradation behavior. The results demonstrated that the degradation rate of modified silk fibroin scaffolds was more rapid than unmodified ones. The content of the β-sheet structure in silk fibroin obviously decreased after acylation, resulting in a high degradation rate. Above all, the degradation behavior of silk fibroin scaffolds could be regulated by acylation to match the requirements of various tissues regeneration.

  13. Dehydration driven changes in the structure and mechanical behavior of electrospun poly (vinyl alcohol) nanofibers

    International Nuclear Information System (INIS)

    Bansal, Ankita; Sinha, Arvind

    2012-01-01

    Electrospun nanofibers of poly (vinyl alcohol) (PVA) are well known for their possible application in different fields, ranging from packaging to tissue engineering. However, biomedical application of these nanofibers gets limited due to its rapid disintegration in water, causing mechanical instability. Addressing this issue, the present manuscript reports ethanol induced dehydration of electrospun PVA nanofibers, and its effects on the structure and mechanical properties of the electrospun system. A systematic variation in the structure and mechanical stability of nanofibers as a function of PVA concentration has also been established in the both hydrated and dehydrated states. - Highlights: ► Study reports structure-property correlation of dehydrated PVA nanofibers. ► Results confirm symmetrical reversal of properties in two states. ► Experimental results are in confirmation with the fusion model of nanofibers.

  14. Effect of Voltage and Flow Rate Electrospinning Parameters on Polyacrylonitrile Electrospun Fibers

    Science.gov (United States)

    Bakar, S. S. S.; Fong, K. C.; Eleyas, A.; Nazeri, M. F. M.

    2018-03-01

    Currently, electrospinning is a very famous technique and widely used for forming polymer nanofibers. In this paper, the Polyacrylonitrile (PAN) nanofibers were prepared in concentration of 10wt% with varied processing parameters that can affect the properties of PAN fiber in term of fiber diameter and electrical conductivity was presented. Voltage of 10, 15 and 20 kV with PAN flow rate of 1 electrospun PAN fibers were then undergo pyrolysis at 800°C for 30 minutes. The resultant PAN nanofibers were then analysed by SEM, XRD and four point probe test after pyrolysis process. SEM image show continuos uniform and smooth surface fibrous structure of electrospun PAN fibers with average diameter of 1.81 μm. The fiber morphology is controlled by manipulating the processing parameters of electrospinning process. The results showed that the resistance of electrospun PAN fibers decreases as the processing parameter changes by increasing the applied voltage and flow rate of electrospinning.

  15. Mesenchymal stem cell cultivation in electrospun scaffolds: mechanistic modeling for tissue engineering.

    Science.gov (United States)

    Paim, Ágata; Tessaro, Isabel C; Cardozo, Nilo S M; Pranke, Patricia

    2018-03-05

    Tissue engineering is a multidisciplinary field of research in which the cells, biomaterials, and processes can be optimized to develop a tissue substitute. Three-dimensional (3D) architectural features from electrospun scaffolds, such as porosity, tortuosity, fiber diameter, pore size, and interconnectivity have a great impact on cell behavior. Regarding tissue development in vitro, culture conditions such as pH, osmolality, temperature, nutrient, and metabolite concentrations dictate cell viability inside the constructs. The effect of different electrospun scaffold properties, bioreactor designs, mesenchymal stem cell culture parameters, and seeding techniques on cell behavior can be studied individually or combined with phenomenological modeling techniques. This work reviews the main culture and scaffold factors that affect tissue development in vitro regarding the culture of cells inside 3D matrices. The mathematical modeling of the relationship between these factors and cell behavior inside 3D constructs has also been critically reviewed, focusing on mesenchymal stem cell culture in electrospun scaffolds.

  16. Electrospun polymeric dressings functionalized with antimicrobial peptides and collagen type I for enhanced wound healing

    Science.gov (United States)

    Felgueiras, H. P.; Amorim, M. T. P.

    2017-10-01

    Modern wound dressings combine medical textiles with active compounds that stimulate wound healing while protecting against infection. Electrospun wound dressings have been extensively studied and the electrospinning technique recognized as an efficient approach for the production of nanoscale fibrous mats. The unique diverse function and architecture of antimicrobial peptides (AMPs) has attracted considerable attention as a tool for the design of new anti-infective drugs. Functionalizing electrospun wound dressings with these AMPs is nowadays being researched. In the present work, we explore these new systems by highlighting the most important characteristics of electropsun wound dressings, revealing the importance of AMPs to wound healing, and the methods available to functionalize the electrospun mats with these molecules. The combined therapeutic potential of collagen type I and these AMP functionalized dressings will be highlighted as well; the significance of these new strategies for the future of wound healing will be clarified.

  17. Electrospun nanofiber reinforcement of dental composites with electromagnetic alignment approach

    International Nuclear Information System (INIS)

    Uyar, Tansel; Çökeliler, Dilek; Doğan, Mustafa; Koçum, Ismail Cengiz; Karatay, Okan; Denkbaş, Emir Baki

    2016-01-01

    Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling, however, when it is used in prosthetic dentistry, fracturing or cracking problems can be seen due to the relatively low strength issues. Besides, acrylic resin is the still prominent material for denture fabrication due to its handy and low cost features. Numerous proposed fillers that are used to produce PMMA composites, however electrospun polyvinylalcohol (PVA) nanofiber fillers for production of PMMA composite resins are not studied as much as the others. The other focus of the practice is to compare both mechanical properties and efficiency of aligned fibers versus non-aligned PVA nanofibers in PMMA based dental composites. Field-controlled electrospinning system is manufactured and provided good alignment in lab scale as one of contributions. Some novel auxiliary electrodes in controlled structure are augmented to obtain different patterns of alignment with a certain range of fiber diameters. Scanning electron microscopy is used for physical characterization to determine the range of fiber diameters. Non-woven fiber has no unique pattern due to chaotic nature of electrospinning process, but aligned fibers have round pattern or crossed lines. These produced fibers are structured as layer-by-layer form with different features, and these features are used in producing PMMA dental composites with different volume ratios. The maximum flexural strength figure shows that fiber load by weight of 0.25% w/w and above improves in the maximum level. As a result, mechanical properties of PMMA dental composites are improved by using PVA nanofibers as a filler, however the improvement was higher when aligned PVA nanofibers are used. The maximum values were 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), and 170 kJ/m 3 (toughness) in three-point bending test. In addition to the positive results of aligned and non-aligned nanofibers it was found

  18. Electrospun nanofiber reinforcement of dental composites with electromagnetic alignment approach

    Energy Technology Data Exchange (ETDEWEB)

    Uyar, Tansel [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Çökeliler, Dilek, E-mail: cokeliler@baskent.edu.tr [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Doğan, Mustafa [Department of Electrical and Electronics Engineering, Başkent University, Ankara 06180 (Turkey); Koçum, Ismail Cengiz [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Karatay, Okan [Department of Electrical and Electronics Engineering, Başkent University, Ankara 06180 (Turkey); Denkbaş, Emir Baki [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey)

    2016-05-01

    Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling, however, when it is used in prosthetic dentistry, fracturing or cracking problems can be seen due to the relatively low strength issues. Besides, acrylic resin is the still prominent material for denture fabrication due to its handy and low cost features. Numerous proposed fillers that are used to produce PMMA composites, however electrospun polyvinylalcohol (PVA) nanofiber fillers for production of PMMA composite resins are not studied as much as the others. The other focus of the practice is to compare both mechanical properties and efficiency of aligned fibers versus non-aligned PVA nanofibers in PMMA based dental composites. Field-controlled electrospinning system is manufactured and provided good alignment in lab scale as one of contributions. Some novel auxiliary electrodes in controlled structure are augmented to obtain different patterns of alignment with a certain range of fiber diameters. Scanning electron microscopy is used for physical characterization to determine the range of fiber diameters. Non-woven fiber has no unique pattern due to chaotic nature of electrospinning process, but aligned fibers have round pattern or crossed lines. These produced fibers are structured as layer-by-layer form with different features, and these features are used in producing PMMA dental composites with different volume ratios. The maximum flexural strength figure shows that fiber load by weight of 0.25% w/w and above improves in the maximum level. As a result, mechanical properties of PMMA dental composites are improved by using PVA nanofibers as a filler, however the improvement was higher when aligned PVA nanofibers are used. The maximum values were 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), and 170 kJ/m{sup 3} (toughness) in three-point bending test. In addition to the positive results of aligned and non-aligned nanofibers it was

  19. Assessing the impact of the maritime silk road

    Directory of Open Access Journals (Sweden)

    Orestis Schinas

    2017-09-01

    Full Text Available The plans for the Maritime Silk Road affect the existing liner services. The purpose of this paper is to quantify using the terms of network theory the impact of these plans and to project the effects on the fleet, utilization, port throughput, and carbon footprint. The analysis is based on publicly available information and reasonable fleet deployment assumptions. It also considers current and alternative routing schedules from Shanghai to Europe. The impact of existing and expected emission control areas (ECAs along the port chains is also considered.

  20. Material quality assessment of silk nanofibers based on swarm intelligence

    Science.gov (United States)

    Brandoli Machado, Bruno; Nunes Gonçalves, Wesley; Martinez Bruno, Odemir

    2013-02-01

    In this paper, we propose a novel approach for texture analysis based on artificial crawler model. Our method assumes that each agent can interact with the environment and each other. The evolution process converges to an equilibrium state according to the set of rules. For each textured image, the feature vector is composed by signatures of the live