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Sample records for silk fibroin fiber-reinforced

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

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    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.

  2. 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.

  3. 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)

  4. 3D freeform printing of silk fibroin.

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    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

  5. 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

  6. Silk fibroin nanostructured materials for biomedical applications

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    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.

  7. 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

  8. 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,

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

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    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.

  10. Self-assembly of silk fibroin under osmotic stress

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    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

  11. 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

  12. 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.

  13. 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.

  14. Silk Fibroin Degradation Related to Rheological and Mechanical Properties.

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    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.

  15. 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)

  16. Preparation and characterization of blends containing silk fibroin and chitosan

    International Nuclear Information System (INIS)

    Moraes, Mariana A. de; Nogueira, Grinia M.; Weska, Raquel F.; Beppu, Marisa M.

    2009-01-01

    The aim of this study was to prepare and characterize blend membranes of silk fibroin and chitosan. Moreover, a conformation of fibroin to a more stable form induced by the addition of chitosan was verified. Blend membranes of fibroin/chitosan were prepared in different proportions and had their crystallinity, structural conformation and thermal stability characterized. The results of crystallographic analysis (XRD) indicated the tendency to higher structural organization caused by the addition of chitosan. FTIR showed that, mainly in a content of chitosan of only 25%, fibroin is present in a more stable form. Thermal analyzes indicate that fibroin is thermally stable and that when its proportion in the blend increases, the temperature in which the degradation is initiated also does so. (author)

  17. 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.

  18. Development and Evaluation of Isoniazid Loaded Silk Fibroin Microsphere

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    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.

  19. Silk Fibroin/Polyvinyl Pyrrolidone Interpenetrating Polymer Network Hydrogels

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    Dajiang Kuang

    2018-02-01

    Full Text Available Silk fibroin hydrogel is an ideal model as biomaterial matrix due to its excellent biocompatibility and used in the field of medical polymer materials. Nevertheless, native fibroin hydrogels show poor transparency and resilience. To settle these drawbacks, an interpenetrating network (IPN of hydrogels are synthesized with changing ratios of silk fibroin/N-Vinyl-2-pyrrolidonemixtures that crosslink by H2O2 and horseradish peroxidase. Interpenetrating polymer network structure can shorten the gel time and the pure fibroin solution gel time for more than a week. This is mainly due to conformation from the random coil to the β-sheet structure changes of fibroin. Moreover, the light transmittance of IPN hydrogel can be as high as more than 97% and maintain a level of 90% within a week. The hydrogel, which mainly consists of random coil, the apertures inside can be up to 200 μm. Elastic modulus increases during the process of gelation. The gel has nearly 95% resilience under the compression of 70% eventually, which is much higher than native fibroin gel. The results suggest that the present IPN hydrogels have excellent mechanical properties and excellent transparency.

  20. 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.

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

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    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.

  2. 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.

  3. Silk fibroin based antibacterial bionanotextiles as wound dressing materials

    Energy Technology Data Exchange (ETDEWEB)

    Çalamak, Semih [Hacettepe University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 06100 Ankara (Turkey); Hacettepe University, Department of Nanotechnology and Nanomedicine, 06800 Ankara (Turkey); Erdoğdu, Ceren; Özalp, Meral [Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Microbiology, 06100 Ankara (Turkey); Ulubayram, Kezban, E-mail: ukezban@hacettepe.edu.tr [Hacettepe University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 06100 Ankara (Turkey); Hacettepe University, Department of Nanotechnology and Nanomedicine, 06800 Ankara (Turkey)

    2014-10-01

    New applications for medical biotextiles have been identified with the development of nanotechnological manufacturing technologies. Combination of nanotechnology and biotextile technology has resulted into a new field called bionanotextiles. Bionanotextiles are used in many areas which include wound dressings, bandages and tissue scaffolds. Silk fibroin (SF) from the cocoon of Bombyx mori, is one of the most favorable wound dressing materials due to its unique properties including biocompatibility, permeability, biodegradability, morphologic flexibility, and proper mechanical properties. The modification of antimicrobial properties of SFs can provide a barrier for bacterial penetration as wound dressing materials. In the present study, antibacterial polyethylenimine (PEI) (10, 20 and 30% (w/w)) was blended with SF and bionanotextiles were successfully fabricated by electrospinning. In addition, silk fibroin nanofibers were also functionalized with sulphate group in order to test whether they exhibit an antibacterial activity or not. Fibroin based bionanotextiles were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The cytotoxicity evaluations were carried out by L929 fibroblasts with MTT assay. The indirect cytotoxicity results demonstrate that all fibroin and PEI/fibroin extracts have no cytotoxicity on L929 cancer cell line. PEI/fibroin bionanotextiles showed strong antibacterial activities against gram positive Staphylococcus aureus and gram negative Pseudomonas aeruginosa. - Highlights: • Bionanotextiles are combination of nanotechnology and biotextile technology. • Bionanotextiles have good antibacterial activity against both of S. aureus and P. aeruginosa. • Antibacterial bionanotextiles are applicable to most of the infected wounds. • No cytotoxicity was observed on L929 cell line.

  4. Silk fibroin based antibacterial bionanotextiles as wound dressing materials

    International Nuclear Information System (INIS)

    Çalamak, Semih; Erdoğdu, Ceren; Özalp, Meral; Ulubayram, Kezban

    2014-01-01

    New applications for medical biotextiles have been identified with the development of nanotechnological manufacturing technologies. Combination of nanotechnology and biotextile technology has resulted into a new field called bionanotextiles. Bionanotextiles are used in many areas which include wound dressings, bandages and tissue scaffolds. Silk fibroin (SF) from the cocoon of Bombyx mori, is one of the most favorable wound dressing materials due to its unique properties including biocompatibility, permeability, biodegradability, morphologic flexibility, and proper mechanical properties. The modification of antimicrobial properties of SFs can provide a barrier for bacterial penetration as wound dressing materials. In the present study, antibacterial polyethylenimine (PEI) (10, 20 and 30% (w/w)) was blended with SF and bionanotextiles were successfully fabricated by electrospinning. In addition, silk fibroin nanofibers were also functionalized with sulphate group in order to test whether they exhibit an antibacterial activity or not. Fibroin based bionanotextiles were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The cytotoxicity evaluations were carried out by L929 fibroblasts with MTT assay. The indirect cytotoxicity results demonstrate that all fibroin and PEI/fibroin extracts have no cytotoxicity on L929 cancer cell line. PEI/fibroin bionanotextiles showed strong antibacterial activities against gram positive Staphylococcus aureus and gram negative Pseudomonas aeruginosa. - Highlights: • Bionanotextiles are combination of nanotechnology and biotextile technology. • Bionanotextiles have good antibacterial activity against both of S. aureus and P. aeruginosa. • Antibacterial bionanotextiles are applicable to most of the infected wounds. • No cytotoxicity was observed on L929 cell line

  5. 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

  6. 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.

  7. 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.

  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. 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

  10. The effect of hirudin modification of silk fibroin on cell growth and antithrombogenicity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiongyu; Tu, Fangfang; Liu, Yunfei; Zhang, Yujin; Li, Helei; Kang, Zhao [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, No. 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Yin, Yin [Laboratory Animal Research Center, Soochow University, Suzhou, Jiangsu 215123 (China); Wang, Jiannan, E-mail: wangjn@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, No. 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China)

    2017-06-01

    Thrombus formation remains a particular challenge for small-diameter vascular grafts. In this study, the direct thrombin inhibitor hirudin (Hir) was used to modify silk fibroin films in an attempt to enhance its antithrombogenic properties. Hir was successfully attached to silk fibroin and uniformly distributed in the regenerative material. Hir-modified films showed good cytocompatibility, and supported adhesion and proliferation of fibroblasts (L929), human umbilical vascular endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs). Proliferation of HAVSMCs was inhibited by increasing Hir concentration. Activated partial thrombin time (APTT), prothrombin time (PT) and thrombin time (TT) of Hir-modified silk fibroin tubular scaffolds (SFTSs) were all increased markedly compared with fresh rabbit blood, ethanol-treated SFTS and unmodified SFTS, demonstrating the improved antithrombogenicity of SFTSs following modification with Hir. - Highlights: • A direct thrombin inhibitor hirudin was used to modify silk fibroin. • Antithrombogenic property of Hir-modified silk fibroin films was improved. • Hir-modified silk fibroin films supported adhesion and proliferation of HUVECs and HAVSMCs. • Proliferation of HAVSMCs on silk fibroin films was inhibited by increasing Hir concentration.

  11. Silk fibroin/pullulan blend films: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shivananda, C. S.; Rao, B. Lakshmeesha; Madhukumar, R.; Asha, S. [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); Sarojini, B. K. [Department of Industrial Chemistry, Mangalore University, Mangalagangotri, Mangalore –574 199 (India); Somashekhar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore – 570 006 (India); Sangappa, Y., E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2016-05-23

    In this work silk fibroin/pullulan blend films have been prepared by solution casting method. The blend films were examined for structural, and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results indicate that with the introduction of pullulan, the interaction between SF and pullulan in the blend films induced the conformation transition of SF films and amorphous phase increases with increasing pullulan ratio. The thermal properties of the blend films were improved significantly in the blend films.

  12. 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.

  13. 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.

  14. 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.

  15. Novel silk fibroin films prepared by formic acid/hydroxyapatite dissolution method

    International Nuclear Information System (INIS)

    Ming, Jinfa; Liu, Zhi; Bie, Shiyu; Zhang, Feng; Zuo, Baoqi

    2014-01-01

    Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6 ± 20.4 nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (β-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0 wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications. - Highlights: • SF fibers were firstly successfully dissolved in FA/HAp solution. • The rheological behavior of SF solution was significantly influenced by HAp contents. • SF nanofibrils were observed in FA/HAp solution with 103.6 ± 20.4 nm in diameter. • SF films prepared by FA/HAp dissolution method had higher mechanical properties

  16. Novel silk fibroin films prepared by formic acid/hydroxyapatite dissolution method

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Jinfa, E-mail: jinfa.ming@gmail.com [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China); Liu, Zhi; Bie, Shiyu [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China); Zhang, Feng [Jiangsu Province Key Laboratory of Stem Cell Research, Medical College, Soochow University, Suzhou 215006 (China); Zuo, Baoqi, E-mail: bqzuo@suda.edu.cn [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China)

    2014-04-01

    Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6 ± 20.4 nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (β-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0 wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications. - Highlights: • SF fibers were firstly successfully dissolved in FA/HAp solution. • The rheological behavior of SF solution was significantly influenced by HAp contents. • SF nanofibrils were observed in FA/HAp solution with 103.6 ± 20.4 nm in diameter. • SF films prepared by FA/HAp dissolution method had higher mechanical properties.

  17. Dissolution behavior of silk fibroin in a low concentration CaCl2-methanol solvent: From morphology to nanostructure.

    Science.gov (United States)

    Shen, Tingting; Wang, Tao; Cheng, Guotao; Huang, Lan; Chen, Lei; Wu, Dayang

    2018-02-05

    Regenerated Silk biomaterials are usually pre-formed from silk fibroin solutions. However, the dissolution of silk fibroin in proper solvents by a simple and low cost way is still a challenge. Here, we employed a CaCl 2 -methanol solvent system with a very low CaCl 2 concentration of 6wt% to dissolve silk fibroin. During the dissolution process, the evaporation of methanol cause the changing of solvation sheath of ions in the solvent. The remaining solvent with the incomplete solvation sheath is absorbed by the silk fiber and interacts with fibroin chains to complete the solvation sheath, which accounts for the dissolution of silk fibroin. Silk fibroin dissolution stops as all the solvation sheaths are complete. The final CaCl 2 concentration is ca. 26% and silk fibroin is completely dissolved with a yield of about 90%. Silk fibroin is dissolved into multi-scale nanofibrils solution which is potential for producing regenerated silk fibroin materials for functional applications. Copyright © 2018. Published by Elsevier B.V.

  18. Crystal growth of calcium carbonate in silk fibroin/sodium alginate hydrogel

    Science.gov (United States)

    Ming, Jinfa; Zuo, Baoqi

    2014-01-01

    As known, silk fibroin-like protein plays a pivotal role during the formation of calcium carbonate (CaCO3) crystals in the nacre sheets. Here, we have prepared silk fibroin/sodium alginate nanofiber hydrogels to serve as templates for calcium carbonate mineralization. In this experiment, we report an interesting finding of calcium carbonate crystal growth in the silk fibroin/sodium alginate nanofiber hydrogels by the vapor diffusion method. The experimental results indicate calcium carbonate crystals obtained from nanofiber hydrogels with different proportions of silk fibroin/sodium alginate are mixture of calcite and vaterite with unusual morphologies. Time-dependent growth study was carried out to investigate the crystallization process. It is believed that nanofiber hydrogels play an important role in the process of crystallization. This study would help in understanding the function of organic polymers in natural mineralization, and provide a novel pathway in the design and synthesis of new materials related unique morphology and structure.

  19. Electromechanical response of silk fibroin hydrogel and conductive polycarbazole/silk fibroin hydrogel composites as actuator material.

    Science.gov (United States)

    Srisawasdi, Thanida; Petcharoen, Karat; Sirivat, Anuvat; Jamieson, Alexander M

    2015-11-01

    Pure silk fibroin (SF) hydrogel and polycarbazole/silk fibroin (SF/PCZ) hydrogels were fabricated by solvent casting technique to evaluate electromechanical responses, dielectric properties, and cantilever deflection properties as functions of electric field strength, SF concentration, glutaraldehyde concentration, and PCZ concentration in the blends. Electromechanical properties were characterized in oscillatory shear mode at electric field strengths ranging from 0 to 600V/mm and at a temperature of 27°C. For both the pristine SF and SF/PCZ hydrogels, the storage modulus response (ΔG') and the storage modulus sensitivity (ΔG'/G'0) increased dramatically with increasing electric field strength. The pristine hydrogel possessed the highest storage modulus sensitivity value of 5.87, a relatively high value when compared with other previously studied electroactive polymers. With the addition of conductive PCZ in SF hydrogel, the storage modulus sensitivity and the relative dielectric constant decreased; the conductive polymer thus provided the softening effect under electric field. In the deflection response, the dielectrophoresis force and deflection distance increased monotonically with electric field strength, where the pure SF hydrogel showed the highest deflection distance and dielectrophoresis force. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Fabrication of silk fibroin film using centrifugal casting technique for corneal tissue engineering.

    Science.gov (United States)

    Lee, Min Chae; Kim, Dong-Kyu; Lee, Ok Joo; Kim, Jung-Ho; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Kim, Su Hyeon; Park, Chan Hum

    2016-04-01

    Films prepared from silk fibroin have shown potential as biomaterials in tissue engineering applications for the eye. Here, we present a novel process for fabrication of silk fibroin films for corneal application. In this work, fabrication of silk fibroin films was simply achieved by centrifugal force. In contrast to the conventional dry casting method, we carried out the new process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force was imposed on an aluminum tube containing silk fibroin solution. In the present study, we also compared the surface roughness, mechanical properties, transparency, and cell proliferation between centrifugal and dry casting method. In terms of surface morphology, films fabricated by the centrifugal casting have less surface roughness than those by the dry casting. For elasticity and transparency, silk fibroin films obtained from the centrifugal casting had favorable results compared with those prepared by dry casting. Furthermore, primary human corneal keratocytes grew better in films prepared by the centrifugal casting. Therefore, our results suggest that this new fabrication process for silk fibroin films offers important potential benefits for corneal tissue regeneration. © 2015 Wiley Periodicals, Inc.

  1. Improving the mechanical properties of collagen-based membranes using silk fibroin for corneal tissue engineering.

    Science.gov (United States)

    Long, Kai; Liu, Yang; Li, Weichang; Wang, Lin; Liu, Sa; Wang, Yingjun; Wang, Zhichong; Ren, Li

    2015-03-01

    Although collagen with outstanding biocompatibility has promising application in corneal tissue engineering, the mechanical properties of collagen-based scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This article describes a toughness reinforced collagen-based membrane using silk fibroin. The collagen-silk fibroin membranes based on collagen [silk fibroin (w/w) ratios of 100:5, 100:10, and 100:20] were prepared by using silk fibroin and cross-linking by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. These membranes were analyzed by scanning electron microscopy and their optical property, and NaCl and tryptophan diffusivity had been tested. The water content was found to be dependent on the content of silk fibroin, and CS10 membrane (loading 10 wt % of silk fibroin) performed the optimal mechanical properties. Also the suture experiments have proved CS10 has high suture retention strength, which can be sutured in rabbit eyes integrally. Moreover, the composite membrane proved good biocompatibility for the proliferation of human corneal epithelial cells in vitro. Lamellar keratoplasty shows that CS10 membrane promoted complete epithelialization in 35 ± 5 days, and their transparency is restored quickly in the first month. Corneal rejection reaction, neovascularization, and keratoconus are not observed. The composite films show potential for use in the field of corneal tissue engineering. © 2014 Wiley Periodicals, Inc.

  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. 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. 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

  5. Silk fibroin/gold nanocrystals: a new example of biopolymer-based nanocomposites

    Science.gov (United States)

    Noinville, S.; Garnier, A.; Courty, A.

    2017-05-01

    The dispersion of nanoparticles in ordered polymer nanostructures can provide control over particle location and orientation, and pave the way for tailored nanomaterials that have enhanced mechanical, electrical, or optical properties. Here we used silk fibroin, a natural biopolymer, to embed gold nanocrystals (NCs), so as to obtain well-ordered structures such as nanowires and self-assembled triangular nanocomposites. Monodisperse gold NCs synthesized in organic media are mixed to silk fibroin and the obtained nanocomposites are characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and Infrared spectroscopy. The optical properties study of gold NCs and silk-gold nanocomposites shows that the Surface Plasmon band is blue shifted compared to gold NCs. The size and shape of NCs gold superlattices can be well controlled by the presence of silk fibroin giving nanowires and also self-assembled triangular nanocomposites as characterized by TEM, FE-SEM and AFM. The strong interaction between gold NCs and silk fibroin is also revealed by the conformation change of silk protein in presence of gold NCs, as shown by FTIR analysis. The formation of such ordered nanocomposites (gold NCs/silk fibroin) will provide new nanoplasmonic devices.

  6. Silk Fibroin-Based Nanoparticles for Drug Delivery

    Science.gov (United States)

    Zhao, Zheng; Li, Yi; Xie, Mao-Bin

    2015-01-01

    Silk fibroin (SF) is a protein-based biomacromolecule with excellent biocompatibility, biodegradability and low immunogenicity. The development of SF-based nanoparticles for drug delivery have received considerable attention due to high binding capacity for various drugs, controlled drug release properties and mild preparation conditions. By adjusting the particle size, the chemical structure and properties, the modified or recombinant SF-based nanoparticles can be designed to improve the therapeutic efficiency of drugs encapsulated into these nanoparticles. Therefore, they can be used to deliver small molecule drugs (e.g., anti-cancer drugs), protein and growth factor drugs, gene drugs, etc. This paper reviews recent progress on SF-based nanoparticles, including chemical structure, properties, and preparation methods. In addition, the applications of SF-based nanoparticles as carriers for therapeutic drugs are also reviewed. PMID:25749470

  7. Structural study of Bombyx mori silk fibroin during processing for regeneration

    Science.gov (United States)

    Ha, Sung-Won

    Bombyx mori silk fibroin has excellent mechanical properties combined with flexibility, tissue compatibility, and high oxygen permeability in the wet condition. This important material should be dissolved and regenerated to be utilized as useful forms such as gel, film, fiber, powder, or non-woven. However, it has long been a problem that the regenerated fibroin materials show poor mechanical properties and brittleness. These problems were technically solved by improving a fiber processing method reported here. The regenerated fibroin fibers showed much better mechanical properties compared to the original silk fibers. This improved technique for the fiber processing of Bombyx mori silk fibroin may be used as a model system for other semi-crystalline fiber forming proteins, becoming available through biotechnology. The physical and chemical properties of the regenerated fibers were characterized by SinTechRTM tensile testing, X-ray diffraction, solid state 13C NMR spectroscopy, and SEM. Unlike synthetic polymers, the molecular weight distribution of Bombyx mori silk fibroin is mono-disperse because silk fibroin is synthesized from DNA template. Genetic studies have revealed the entire amino acid sequence of Bombyx mori silk fibroin. It is known that the crystalline silk II structure is composed of hexa-amino acid sequences, GAGAGS. However, in the amino acid sequence of Bombyx mori silk fibroin heavy chain, there are present 11 chemically irregular but evolutionarily conserved sequences with about 31 amino acid residues (irregular GT˜GT sequences). The structure and role of these irregular sequences have remained unknown. One of the most frequently appearing irregular sequences was synthesized by a peptide synthesizer. The three-dimensional structure of this irregular silk peptide was studied by the high resolution two-dimensional NMR technique. The three-dimensional structure of this peptide shows that it makes a turn or loop structure (distorted O shape), which

  8. Silk fibroin porous scaffolds for nucleus pulposus tissue engineering

    International Nuclear Information System (INIS)

    Zeng, Chao; Yang, Qiang; Zhu, Meifeng; Du, Lilong; Zhang, Jiamin; Ma, Xinlong; Xu, Baoshan; Wang, Lianyong

    2014-01-01

    Intervertebral discs (IVDs) are structurally complex tissue that hold the vertebrae together and provide mobility to spine. The nucleus pulposus (NP) degeneration often results in degenerative IVD disease that is one of the most common causes of back and neck pain. Tissue engineered nucleus pulposus offers an alternative approach to regain the function of the degenerative IVD. The aim of this study is to determine the feasibility of porous silk fibroin (SF) scaffolds fabricated by paraffin-sphere-leaching methods with freeze-drying in the application of nucleus pulposus regeneration. The prepared scaffold possessed high porosity of 92.38 ± 5.12% and pore size of 165.00 ± 8.25 μm as well as high pore interconnectivity and appropriate mechanical properties. Rabbit NP cells were seeded and cultured on the SF scaffolds. Scanning electron microscopy, histology, biochemical assays and mechanical tests revealed that the porous scaffolds could provide an appropriate microstructure and environment to support adhesion, proliferation and infiltration of NP cells in vitro as well as the generation of extracellular matrix. The NP cell–scaffold construction could be preliminarily formed after subcutaneously implanted in a nude mice model. In conclusion, The SF porous scaffold offers a potential candidate for tissue engineered NP tissue. - Highlights: • Paraffin microsphere-leaching method is used to fabricate silk fibroin scaffold. • The scaffold has appropriate mechanical property, porosity and pore size • The scaffold supports growth and infiltration of nucleus pulposus cells. • Nucleus pulposus cells can secrete extracellular matrix in the scaffolds. • The scaffold is a potential candidate for tissue engineered nucleus pulposus

  9. Silk fibroin porous scaffolds for nucleus pulposus tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Chao; Yang, Qiang [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Tianjin Medical University, Tianjin 300070 (China); Zhu, Meifeng [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Du, Lilong [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Tianjin Medical University, Tianjin 300070 (China); Zhang, Jiamin [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Ma, Xinlong [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Xu, Baoshan, E-mail: xubaoshan99@126.com [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Wang, Lianyong, E-mail: wly@nankai.edu.cn [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China)

    2014-04-01

    Intervertebral discs (IVDs) are structurally complex tissue that hold the vertebrae together and provide mobility to spine. The nucleus pulposus (NP) degeneration often results in degenerative IVD disease that is one of the most common causes of back and neck pain. Tissue engineered nucleus pulposus offers an alternative approach to regain the function of the degenerative IVD. The aim of this study is to determine the feasibility of porous silk fibroin (SF) scaffolds fabricated by paraffin-sphere-leaching methods with freeze-drying in the application of nucleus pulposus regeneration. The prepared scaffold possessed high porosity of 92.38 ± 5.12% and pore size of 165.00 ± 8.25 μm as well as high pore interconnectivity and appropriate mechanical properties. Rabbit NP cells were seeded and cultured on the SF scaffolds. Scanning electron microscopy, histology, biochemical assays and mechanical tests revealed that the porous scaffolds could provide an appropriate microstructure and environment to support adhesion, proliferation and infiltration of NP cells in vitro as well as the generation of extracellular matrix. The NP cell–scaffold construction could be preliminarily formed after subcutaneously implanted in a nude mice model. In conclusion, The SF porous scaffold offers a potential candidate for tissue engineered NP tissue. - Highlights: • Paraffin microsphere-leaching method is used to fabricate silk fibroin scaffold. • The scaffold has appropriate mechanical property, porosity and pore size • The scaffold supports growth and infiltration of nucleus pulposus cells. • Nucleus pulposus cells can secrete extracellular matrix in the scaffolds. • The scaffold is a potential candidate for tissue engineered nucleus pulposus.

  10. Self-assembly model, hepatocytes attachment and inflammatory response for silk fibroin/chitosan scaffolds

    International Nuclear Information System (INIS)

    She Zhending; Feng Qingling; Liu Weiqiang

    2009-01-01

    Silk fibroin is an attractive natural fibrous protein for biomedical application due to its good biocompatibility and high tensile strength. Silk fibroin is apt to form a sheet-like structure during the freeze-drying process, which is not suitable for the scaffold of tissue engineering. In our former study, the adding of chitosan promoted the self-assembly of silk fibroin/chitosan (SFCS) into a three-dimensional (3D) homogeneous porous structure. In this study, a model of the self-assembly is proposed; furthermore, hepatocytes attachment and inflammatory response for the SFCS scaffold were examined. The rigid chain of chitosan may be used as a template for β-sheet formation of silk fibroin, and this may break the sheet structure of the silk fibroin scaffold and promote the formation of a 3D porous structure of the SFCS scaffold. Compared with the polylactic glycolic acid scaffold, the SFCS scaffold further facilitates the attachment of hepatocytes. To investigate the inflammatory response, SFCS scaffolds were implanted into the greater omentum of rats. From the results of implantation, we could demonstrate in vivo that the implantation of SFCS scaffolds resulted in only slight inflammation. Keeping the good histocompatibility and combining the advantages of both fibroin and chitosan, the SFCS scaffold could be a prominent candidate for soft tissue engineering, for example, in the liver.

  11. Self-assembly model, hepatocytes attachment and inflammatory response for silk fibroin/chitosan scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    She Zhending; Feng Qingling [State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu Weiqiang, E-mail: biomater@mail.tsinghua.edu.c [Center for Advanced Materials and Biotechnology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2009-08-15

    Silk fibroin is an attractive natural fibrous protein for biomedical application due to its good biocompatibility and high tensile strength. Silk fibroin is apt to form a sheet-like structure during the freeze-drying process, which is not suitable for the scaffold of tissue engineering. In our former study, the adding of chitosan promoted the self-assembly of silk fibroin/chitosan (SFCS) into a three-dimensional (3D) homogeneous porous structure. In this study, a model of the self-assembly is proposed; furthermore, hepatocytes attachment and inflammatory response for the SFCS scaffold were examined. The rigid chain of chitosan may be used as a template for beta-sheet formation of silk fibroin, and this may break the sheet structure of the silk fibroin scaffold and promote the formation of a 3D porous structure of the SFCS scaffold. Compared with the polylactic glycolic acid scaffold, the SFCS scaffold further facilitates the attachment of hepatocytes. To investigate the inflammatory response, SFCS scaffolds were implanted into the greater omentum of rats. From the results of implantation, we could demonstrate in vivo that the implantation of SFCS scaffolds resulted in only slight inflammation. Keeping the good histocompatibility and combining the advantages of both fibroin and chitosan, the SFCS scaffold could be a prominent candidate for soft tissue engineering, for example, in the liver.

  12. Silk fibroin/chitosan thin film promotes osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells.

    Science.gov (United States)

    Li, Da-Wei; He, Jin; He, Feng-Li; Liu, Ya-Li; Liu, Yang-Yang; Ye, Ya-Jing; Deng, Xudong; Yin, Da-Chuan

    2018-04-01

    As a biodegradable polymer thin film, silk fibroin/chitosan composite film overcomes the defects of pure silk fibroin and chitosan films, respectively, and shows remarkable biocompatibility, appropriate hydrophilicity and mechanical properties. Silk fibroin/chitosan thin film can be used not only as metal implant coating for bone injury repair, but also as tissue engineering scaffold for skin, cornea, adipose, and other soft tissue injury repair. However, the biocompatibility of silk fibroin/chitosan thin film for mesenchymal stem cells, a kind of important seed cell of tissue engineering and regenerative medicine, is rarely reported. In this study, silk fibroin/chitosan film was prepared by solvent casting method, and the rat bone marrow-derived mesenchymal stem cells were cultured on the silk fibroin/chitosan thin film. Osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells were induced, respectively. The proliferation ability, osteogenic and adipogenic differentiation abilities of rat bone marrow-derived mesenchymal stem cells were systematically compared between silk fibroin/chitosan thin film and polystyrene tissue culture plates. The results showed that silk fibroin/chitosan thin film not only provided a comparable environment for the growth and proliferation of rat bone marrow-derived mesenchymal stem cells but also promoted their osteogenic and adipogenic differentiation. This work provided information of rat bone marrow-derived mesenchymal stem cells behavior on silk fibroin/chitosan thin film and extended the application of silk fibroin/chitosan thin film. Based on the results, we suggested that the silk fibroin/chitosan thin film could be a promising material for tissue engineering of bone, cartilage, adipose, and skin.

  13. Nucleation of hydroxyapatite on Antheraea pernyi (A. pernyi) silk fibroin film.

    Science.gov (United States)

    Yang, Mingying; Shuai, Yajun; Zhou, Guanshan; Mandal, Namita; Zhu, Liangjun

    2014-01-01

    Antheraea pernyi (A. pernyi) silk fibroin, which is spun from a wild silkworm, has increasingly attracted interest in the field of tissue engineering. The aim of this study was to investigate the nucleation of hydroxyapatite (HAp) on A. pernyi fibroin film. Von Kossa staining proved that A. pernyi fibroin had Ca binding activity. The A. pernyi fibroin film was mineralized with HAp crystals by alternative soaking in calcium and phosphate solutions. Spherical crystals were nucleated on the A. pernyi fibroin film according to scanning electron microscopeimaging results. The FT-IR and X-ray diffraction spectra confirmed that these spherical crystals were HAp. The results of in vitro cell culture using MG-63 cells demonstrated that the mineralized A. pernyi fibroin film showed excellent cytocompatibility and sound improvement of the MG-63 cellviability.

  14. Biodegradable materials based on silk fibroin and keratin.

    Science.gov (United States)

    Vasconcelos, Andreia; Freddi, Giuliano; Cavaco-Paulo, Artur

    2008-04-01

    Wool and silk were dissolved and used for the preparation of blended films. Two systems are proposed: (1) blend films of silk fibroin and keratin aqueous solutions and (2) silk fibroin and keratin dissolved in formic acid. The FTIR spectra of pure films cast from aqueous solutions indicated that the keratin secondary structure mainly consists of alpha-helix and random coil conformations. The IR spectrum of pure SF is characteristic of films with prevalently amorphous structure (random coil conformation). Pure keratin film cast from formic acid shows an increase in the amount of beta-sheet and disordered keratin structures. The FTIR pattern of SF dissolved in formic acid is characteristic of films with prevalently beta-sheet conformations with beta-sheet crystallites embedded in an amorphous matrix. The thermal behavior of the blends confirmed the FTIR results. DSC curve of pure SF is typical of amorphous SF and the curve of pure keratin show the characteristic melting peak of alpha-helices for the aqueous system. These patterns are no longer observed in the films cast from formic acid due to the ability of formic acid to induce crystallization of SF and to increase the amount of beta-sheet structures on keratin. The nonlinear trend of the different parameters obtained from FTIR analysis and DSC curves of both SF/keratin systems indicate that when proteins are mixed they do not follow additives rules but are able to establish intermolecular interactions. Degradable polymeric biomaterials are preferred candidates for medical applications. It was investigated the degradation behavior of both SF/keratin systems by in vitro enzymatic incubation with trypsin. The SF/keratin films cast from water underwent a slower biological degradation than the films cast from formic acid. The weight loss obtained is a function of the amount of keratin in the blend. This study encourages the further investigation of the type of matrices presented here to be applied whether in scaffolds

  15. 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.

  16. 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.

  17. 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.

  18. 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 samples were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at an appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The soluble silk protein content increased from 0.462 to 0.653 mg protein/mg silk fibroin 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)

  19. Tyrosinase-Mediated Construction of a Silk Fibroin/Elastin Nanofiber Bioscaffold.

    Science.gov (United States)

    Hong, Yanqing; Zhu, Xueke; Wang, Ping; Fu, Haitian; Deng, Chao; Cui, Li; Wang, Qiang; Fan, Xuerong

    2016-04-01

    Elastin has characteristics of elasticity, biological activity, and mechanical stability. In the present work, tyrosinase-mediated construction of a bioscaffold with silk fibroin and elastin was carried out, aiming at developing a novel medical biomaterial. The efficiency of enzymatic oxidation of silk fibroin and the covalent reaction between fibroin and elastin were examined by spectrophotometry, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and size exclusion chromatography (SEC). The properties of composite air-dried and nanofiber scaffolds were investigated. The results reveal that elastin was successfully bonded to silk fibroins, resulting in an increase in molecular weight of fibroin proteins. ATR-FTIR spectra indicated that tyrosinase treatment impacted the conformational structure of fibroin-based membrane. The thermal behaviors and mechanical properties of the tyrosinase-treated scaffolds were also improved compared with the untreated group. NIH/3T3 cells exhibited optimum densities when grown on the nanofiber scaffold, implying that the nanofiber scaffold has enhanced biocompatibility compared to the air-dried scaffold. A biological nanofiber scaffold constructed from tyrosinase-treated fibroin and elastin could potentially be utilized in biomedical applications.

  20. Silk Fibroin Aqueous-Based Adhesives Inspired by Mussel Adhesive Proteins.

    Science.gov (United States)

    Burke, Kelly A; Roberts, Dane C; Kaplan, David L

    2016-01-11

    Silk fibroin from the domesticated silkworm Bombyx mori is a naturally occurring biopolymer with charged hydrophilic terminal regions that end-cap a hydrophobic core consisting of repeating sequences of glycine, alanine, and serine residues. Taking inspiration from mussels that produce proteins rich in L-3,4-dihydroxyphenylalanine (DOPA) to adhere to a variety of organic and inorganic surfaces, the silk fibroin was functionalized with catechol groups. Silk fibroin was selected for its high molecular weight, tunable mechanical and degradation properties, aqueous processability, and wide availability. The synthesis of catechol-functionalized silk fibroin polymers containing varying amounts of hydrophilic polyethylene glycol (PEG, 5000 g/mol) side chains was carried out to balance silk hydrophobicity with PEG hydrophilicity. The efficiency of the catechol functionalization reaction did not vary with PEG conjugation over the range studied, although tuning the amount of PEG conjugated was essential for aqueous solubility. Adhesive bonding and cell compatibility of the resulting materials were investigated, where it was found that incorporating as little as 6 wt % PEG prior to catechol functionalization resulted in complete aqueous solubility of the catechol conjugates and increased adhesive strength compared with silk lacking catechol functionalization. Furthermore, PEG-silk fibroin conjugates maintained their ability to form β-sheet secondary structures, which can be exploited to reduce swelling. Human mesenchymal stem cells (hMSCs) proliferated on the silks, regardless of PEG and catechol conjugation. These materials represent a protein-based approach to catechol-based adhesives, which we envision may find applicability as biodegradable adhesives and sealants.

  1. Determination of molecular weight of silk fibroin by non-gel sieving capillary electrophoresis.

    Science.gov (United States)

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

    2010-01-01

    A simple non-gel sieving capillary electrophoresis (NGSCE) method was established to determine the MW of silk fibroin using CE. The background electrolyte with a pH of 8.8 was based on three components: polyethylene glycol, tris(hydroxymethyl)aminomethane, and sodium dodecyl sulfate (SDS). NGSCE showed a good linear relationship with satisfactory reproducibility between the migration time and the MW of standard proteins. It was found that the regenerated silk fibroin had an MW around 83 kDa with a wide MW distribution (MWD). This absolute value is lower than the result obtained from SDS-polyacrylamide gel electrophoresis due to the different principles of the methods, but their similar MWD shapes indicated that NGSCE could be a feasible, highly sensitive, rapid method for determination of the MW of silk fibroin.

  2. 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.

  3. 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.

  4. Production of Curcumin-Loaded Silk Fibroin Nanoparticles for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Mercedes G. Montalbán

    2018-02-01

    Full Text Available Curcumin, extracted from the rhizome of Curcuma longa, has been widely used in medicine for centuries due to its anti-inflammatory, anti-cancer, anti-oxidant and anti-microbial effects. However, its bioavailability during treatments is poor because of its low solubility in water, slow dissolution rate and rapid intestinal metabolism. For these reasons, improving the therapeutic efficiency of curcumin using nanocarriers (e.g., biopolymer nanoparticles has been a research focus, to foster delivery of the curcumin inside cells due to their small size and large surface area. Silk fibroin from the Bombyx mori silkworm is a biopolymer characterized by its biocompatibility, biodegradability, amphiphilic chemistry, and excellent mechanical properties in various material formats. These features make silk fibroin nanoparticles useful vehicles for delivering therapeutic drugs, such as curcumin. Curcumin-loaded silk fibroin nanoparticles were synthesized using two procedures (physical adsorption and coprecipitation more scalable than methods previously described using ionic liquids. The results showed that nanoparticle formulations were 155 to 170 nm in diameter with a zeta potential of approximately −45 mV. The curcumin-loaded silk fibroin nanoparticles obtained by both processing methods were cytotoxic to carcinogenic cells, while not decreasing viability of healthy cells. In the case of tumor cells, curcumin-loaded silk fibroin nanoparticles presented higher efficacy in cytotoxicity against neuroblastoma cells than hepatocarcinoma cells. In conclusion, curcumin-loaded silk fibroin nanoparticles constitute a biodegradable and biocompatible delivery system with the potential to treat tumors by local, long-term sustained drug delivery.

  5. Production of Curcumin-Loaded Silk Fibroin Nanoparticles for Cancer Therapy

    Science.gov (United States)

    Coburn, Jeannine M.; Cenis, José L.; Víllora, Gloria; Kaplan, David L.

    2018-01-01

    Curcumin, extracted from the rhizome of Curcuma longa, has been widely used in medicine for centuries due to its anti-inflammatory, anti-cancer, anti-oxidant and anti-microbial effects. However, its bioavailability during treatments is poor because of its low solubility in water, slow dissolution rate and rapid intestinal metabolism. For these reasons, improving the therapeutic efficiency of curcumin using nanocarriers (e.g., biopolymer nanoparticles) has been a research focus, to foster delivery of the curcumin inside cells due to their small size and large surface area. Silk fibroin from the Bombyx mori silkworm is a biopolymer characterized by its biocompatibility, biodegradability, amphiphilic chemistry, and excellent mechanical properties in various material formats. These features make silk fibroin nanoparticles useful vehicles for delivering therapeutic drugs, such as curcumin. Curcumin-loaded silk fibroin nanoparticles were synthesized using two procedures (physical adsorption and coprecipitation) more scalable than methods previously described using ionic liquids. The results showed that nanoparticle formulations were 155 to 170 nm in diameter with a zeta potential of approximately −45 mV. The curcumin-loaded silk fibroin nanoparticles obtained by both processing methods were cytotoxic to carcinogenic cells, while not decreasing viability of healthy cells. In the case of tumor cells, curcumin-loaded silk fibroin nanoparticles presented higher efficacy in cytotoxicity against neuroblastoma cells than hepatocarcinoma cells. In conclusion, curcumin-loaded silk fibroin nanoparticles constitute a biodegradable and biocompatible delivery system with the potential to treat tumors by local, long-term sustained drug delivery. PMID:29495296

  6. Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere for cartilage repair

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianhua; Yang, Qiu; Cheng, Niangmei [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Tao, Xiaojun [Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha, 410013, Hunan (China); Zhang, Zhihua; Sun, Xiaomin [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Zhang, Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Key Laboratory of Biomedical Materials of Tianjin, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192 (China)

    2016-04-01

    For cartilage repair, ideal scaffolds should mimic natural extracellular matrix (ECM) exhibiting excellent characteristics, such as biocompatibility, suitable porosity, and good cell affinity. This study aimed to prepare a collagen/silk fibroin composite scaffold incorporated with poly-lactic-co-glycolic acid (PLGA) microsphere that can be applied in repairing cartilage. To obtain optimum conditions for manufacturing a composite scaffold, a scaffold composed of different collagen-to-silk fibroin ratios was evaluated by determining porosity, water absorption, loss rate in hot water, and cell proliferation. Results suggested that the optimal ratio of collagen and silk fibroin composite scaffold was 7:3. The microstructure and morphological characteristics of the obtained scaffold were also examined through scanning electron microscopy and Fourier transform infrared spectroscopy. The results of in vitro fluorescence staining of bone marrow stromal cells revealed that collagen/silk fibroin composite scaffold enhanced cell proliferation without eliciting side effects. The prepared composite scaffold incorporated with PLGA microsphere was implanted in fully thick articular cartilage defects in rabbits. Collagen/silk fibroin composite scaffold with PLGA microspheres could enhance articular cartilage regeneration and integration between the repaired cartilage and the surrounding cartilage. Therefore, this composite will be a promising material for cartilage repair and regeneration. - Highlights: • Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere proposed for cartilage repair was created. • In vivo, scaffold could enhance cartilage regeneration and integration between the repaired and surrounding cartilage. • In vitro, scaffold exhibits excellent characteristics, such as, improved porosity water absorption and good cell affinity.

  7. Human amniotic epithelial cells combined with silk fibroin scaffold in the repair of spinal cord injury

    Directory of Open Access Journals (Sweden)

    Ting-gang Wang

    2016-01-01

    Full Text Available Treatment and functional reconstruction after central nervous system injury is a major medical and social challenge. An increasing number of researchers are attempting to use neural stem cells combined with artificial scaffold materials, such as fibroin, for nerve repair. However, such approaches are challenged by ethical and practical issues. Amniotic tissue, a clinical waste product, is abundant, and amniotic epithelial cells are pluripotent, have low immunogenicity, and are not the subject of ethical debate. We hypothesized that amniotic epithelial cells combined with silk fibroin scaffolds would be conducive to the repair of spinal cord injury. To test this, we isolated and cultured amniotic epithelial cells, and constructed complexes of these cells and silk fibroin scaffolds. Implantation of the cell-scaffold complex into a rat model of spinal cord injury resulted in a smaller glial scar in the damaged cord tissue than in model rats that received a blank scaffold, or amniotic epithelial cells alone. In addition to a milder local immunological reaction, the rats showed less inflammatory cell infiltration at the transplant site, milder host-versus-graft reaction, and a marked improvement in motor function. These findings confirm that the transplantation of amniotic epithelial cells combined with silk fibroin scaffold can promote the repair of spinal cord injury. Silk fibroin scaffold can provide a good nerve regeneration microenvironment for amniotic epithelial cells.

  8. Artificial Auricular Cartilage Using Silk Fibroin and Polyvinyl Alcohol Hydrogel

    Science.gov (United States)

    Lee, Jung Min; Sultan, Md. Tipu; Kim, Soon Hee; Kumar, Vijay; Yeon, Yeung Kyu; Lee, Ok Joo; Park, Chan Hum

    2017-01-01

    Several methods for auricular cartilage engineering use tissue engineering techniques. However, an ideal method for engineering auricular cartilage has not been reported. To address this issue, we developed a strategy to engineer auricular cartilage using silk fibroin (SF) and polyvinyl alcohol (PVA) hydrogel. We constructed different hydrogels with various ratios of SF and PVA by using salt leaching, silicone mold casting, and freeze-thawing methods. We characterized each of the hydrogels in terms of the swelling ratio, tensile strength, pore size, thermal properties, morphologies, and chemical properties. Based on the cell viability results, we found a blended hydrogel composed of 50% PVA and 50% SF (P50/S50) to be the best hydrogel among the fabricated hydrogels. An intact 3D ear-shaped auricular cartilage formed six weeks after the subcutaneous implantation of a chondrocyte-seeded 3D ear-shaped P50/S50 hydrogel in rats. We observed mature cartilage with a typical lacunar structure both in vitro and in vivo via histological analysis. This study may have potential applications in auricular tissue engineering with a human ear-shaped hydrogel. PMID:28777314

  9. Controlling silk fibroin microspheres via molecular weight distribution

    International Nuclear Information System (INIS)

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui; Zhang, Ke-Qin

    2015-01-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K 2 HPO 4 –KH 2 PO 4 ). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications

  10. Fabrication of silk fibroin nanoparticles for controlled drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Zheng; Chen Aizheng; Li Yi, E-mail: tcliyi@polyu.edu.hk; Hu Junyan; Liu Xuan; Li Jiashen; Zhang Yu; Li Gang; Zheng Zijian [Hong Kong Polytechnic University, Institute of Textiles and Clothing (Hong Kong)

    2012-03-15

    A novel solution-enhanced dispersion by supercritical CO{sub 2} (SEDS) was employed to prepare silk fibroin (SF) nanoparticles. The resulting SF nanoparticles exhibited a good spherical shape, a smooth surface, and a narrow particle size distribution with a mean particle diameter of about 50 nm. The results of X-ray powder diffraction, thermo gravimetry-differential scanning calorimetry, and Fourier transform infrared spectroscopy analysis of the SF nanoparticles before and after ethanol treatment indicated conformation transition of SF nanoparticles from random coil to {beta}-sheet form and thus water insolubility. The MTS assay also suggested that the SF nanoparticles after ethanol treatment imposed no toxicity. A non-steroidal anti-inflammatory drug, indomethacin (IDMC), was chosen as the model drug and was encapsulated in SF nanoparticles by the SEDS process. The resulting IDMC-SF nanoparticles, after ethanol treatment, possessed a theoretical average drug load of 20%, an actual drug load of 2.05%, and an encapsulation efficiency of 10.23%. In vitro IDMC release from the IDMC-SF nanoparticles after ethanol treatment showed a significantly sustained release over 2 days. These studies of SF nanoparticles indicated the suitability of the SF nanoparticles prepared by the SEDS process as a biocompatible carrier to deliver drugs and also the feasibility of using the SEDS process to reach the goal of co-precipitation of drug and SF as composite nanoparticles for controlled drug delivery.

  11. Fabrication of silk fibroin nanoparticles for controlled drug delivery

    International Nuclear Information System (INIS)

    Zhao Zheng; Chen Aizheng; Li Yi; Hu Junyan; Liu Xuan; Li Jiashen; Zhang Yu; Li Gang; Zheng Zijian

    2012-01-01

    A novel solution-enhanced dispersion by supercritical CO 2 (SEDS) was employed to prepare silk fibroin (SF) nanoparticles. The resulting SF nanoparticles exhibited a good spherical shape, a smooth surface, and a narrow particle size distribution with a mean particle diameter of about 50 nm. The results of X-ray powder diffraction, thermo gravimetry-differential scanning calorimetry, and Fourier transform infrared spectroscopy analysis of the SF nanoparticles before and after ethanol treatment indicated conformation transition of SF nanoparticles from random coil to β-sheet form and thus water insolubility. The MTS assay also suggested that the SF nanoparticles after ethanol treatment imposed no toxicity. A non-steroidal anti-inflammatory drug, indomethacin (IDMC), was chosen as the model drug and was encapsulated in SF nanoparticles by the SEDS process. The resulting IDMC–SF nanoparticles, after ethanol treatment, possessed a theoretical average drug load of 20%, an actual drug load of 2.05%, and an encapsulation efficiency of 10.23%. In vitro IDMC release from the IDMC–SF nanoparticles after ethanol treatment showed a significantly sustained release over 2 days. These studies of SF nanoparticles indicated the suitability of the SF nanoparticles prepared by the SEDS process as a biocompatible carrier to deliver drugs and also the feasibility of using the SEDS process to reach the goal of co-precipitation of drug and SF as composite nanoparticles for controlled drug delivery.

  12. Controlling silk fibroin microspheres via molecular weight distribution

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Zhang, Ke-Qin, E-mail: kqzhang@suda.edu.cn [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Research Center of Cooperative Innovation for Functional Organic/Polymer Material Micro/Nanofabrication, Soochow University, Suzhou, Jiangsu 215123 (China)

    2015-05-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K{sub 2}HPO{sub 4}–KH{sub 2}PO{sub 4}). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications.

  13. Synthesis and characterization of dense membranes of silk fibroin with glycerin

    International Nuclear Information System (INIS)

    Silva, Mariana F.; Moraes, Mariana A. de; Weska, Raquel F.; Nogueira, Grinia M.; Beppu, Marisa M.

    2009-01-01

    The addition of plasticizers seeks improvements in mechanical properties of dense membranes of silk fibroin with possible interactions by hydrogen bonds. The aim of the present study was to produce and characterize dense membranes of silk fibroin containing glycerin in two different concentrations. The characterization of the membranes was performed from scanning electron microscopy (SEM), mechanical traction tests, infrared spectroscopy (FTIR-ATR) and X-ray diffraction (XRD). The results indicated that the addition of glycerin allowed obtaining homogeneous and more crystalline membranes and improved their properties of elongation. (author)

  14. New oral dosage form for elderly patients. II. Release behavior of benfotiamine from silk fibroin gel.

    Science.gov (United States)

    Hanawa, T; Watanabe, A; Tsuchiya, T; Ikoma, R; Hidaka, M; Sugihara, M

    1995-05-01

    Silk fibroin gel (SFG) containing benfotiamine (BTMP) was prepared. The release behavior of BTMP from SFG was studied as a function of silk fibroin (SF) content and glycerol content, and the influence of the existence of beta-cyclodextrin (beta-CD) on the physicochemical properties of SFG were investigated. The release rate of BTMP from SFG was retarded by an increase in SF concentration. The addition of beta-CD affected both the release properties and rheological properties of the SFG. It was found from the results of the "paddle-bead method" that the release profiles of BTMP from SFG were inversely proportional to the SFG firmness.

  15. Peptide-Graphene Interactions Enhance the Mechanical Properties of Silk Fibroin.

    Science.gov (United States)

    Cheng, Yuan; Koh, Leng-Duei; Li, Dechang; Ji, Baohua; Zhang, Yingyan; Yeo, Jingjie; Guan, Guijian; Han, Ming-Yong; Zhang, Yong-Wei

    2015-10-07

    Studies reveal that biomolecules can form intriguing molecular structures with fascinating functionalities upon interaction with graphene. Then, interesting questions arise. How does silk fibroin interact with graphene? Does such interaction lead to an enhancement in its mechanical properties? In this study, using large-scale molecular dynamics simulations, we first examine the interaction of graphene with several typical peptide structures of silk fibroin extracted from different domains of silk fibroin, including pure amorphous (P1), pure crystalline (P2), a segment from N-terminal (P3), and a combined amorphous and crystalline segment (P4), aiming to reveal their structural modifications. Our study shows that graphene can have intriguing influences on the structures formed by the peptides with sequences representing different domains of silk fibroin. In general, for protein domains with stable structure and strong intramolecular interaction (e.g., β-sheets), graphene tends to compete with the intramolecular interactions and thus weaken the interchain interaction and reduce the contents of β-sheets. For the silk domains with random or less ordered secondary structures and weak intramolecular interactions, graphene tends to enhance the stability of peptide structures; in particular, it increases the contents of helical structures. Thereafter, tensile simulations were further performed on the representative peptides to investigate how such structure modifications affect their mechanical properties. It was found that the strength and resilience of the peptides are enhanced through their interaction with graphene. The present work reveals interesting insights into the interactions between silk peptides and graphene, and contributes in the efforts to enhance the mechanical properties of silk fibroin.

  16. Novel two-step method to form silk fibroin fibrous hydrogel

    International Nuclear Information System (INIS)

    Ming, Jinfa; Li, Mengmeng; Han, Yuhui; Chen, Ying; Li, Han; Zuo, Baoqi; Pan, Fukui

    2016-01-01

    Hydrogels prepared by silk fibroin solution have been studied. However, mimicking the nanofibrous structures of extracellular matrix for fabricating biomaterials remains a challenge. Here, a novel two-step method was applied to prepare fibrous hydrogels using regenerated silk fibroin solution containing nanofibrils in a range of tens to hundreds of nanometers. When the gelation process of silk solution occurred, it showed a top-down type gel within 30 min. After gelation, silk fibroin fibrous hydrogels exhibited nanofiber network morphology with β-sheet structure. Moreover, the compressive stress and modulus of fibrous hydrogels were 31.9 ± 2.6 and 2.8 ± 0.8 kPa, respectively, which was formed using 2.0 wt.% concentration solutions. In addition, fibrous hydrogels supported BMSCs attachment and proliferation over 12 days. This study provides important insight in the in vitro processing of silk fibroin into useful new materials. - Highlights: • SF fibrous hydrogel was prepared by a novel two-step method. • SF solution containing nanofibrils in a range of tens to hundreds of nanometers was prepared. • Gelation process was top-down type gel with several minutes. • SF fibrous hydrogels exhibited nanofiber network morphology with β-sheet structure. • Fibrous hydrogels had higher compressive stresses superior to porous hydrogels.

  17. Silk fibroin membranes from solvent-crystallized silk fibroin/gelatin blends: Effects of blend and solvent composition

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Eun S. [Fiber and Polymer Science Program, North Carolina State University, Raleigh, NC 27695 (United States); Frankowski, David J. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Hudson, Samuel M. [Fiber and Polymer Science Program, North Carolina State University, Raleigh, NC 27695 (United States); Spontak, Richard J. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 (United States) and Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States)]. E-mail: Rich_Spontak@ncsu.edu

    2007-04-15

    Protein membranes have been prepared by mixing gelatin (G) with Bombyx mori silk fibroin (SF) and using aqueous methanol (MeOH) to induce SF crystallization. Amorphous blends of these polymers appear quasi-homogeneous, as discerned from visual observation, electron microscopy and Fourier-transform infrared (FTIR) spectroscopy. Upon subsequent exposure to aqueous MeOH, SF undergoes a conformational change from random-coil to {beta}-sheet. This transformation occurs in pure SF, as well as in each of the G/SF blends, as discerned from FTIR spectroscopy and thermal calorimetry. The influence of MeOH-induced SF crystallization on structure and property development has been measured as functions of blend and solvent composition. By preserving a support scaffold above the G helix-to-coil transition temperature, the formation of crystalline SF networks in G/SF blends can be used to stabilize G-based hydrogels or generate SF membranes for biomaterial, pharmaceutical and gas-separation purposes. The present study not only examines the properties of G/SF blends before and after SF crystallization, but also establishes the foundation for future research into thermally-responsive G/SF bioconjugates.

  18. Enzymatic degradation behavior and cytocompatibility of silk fibroin-starch-chitosan conjugate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Baran, Erkan T., E-mail: erkantur@metu.edu.tr; Tuzlakoglu, Kadriye, E-mail: kadriye@dep.uminho.pt; Mano, Joao F., E-mail: jmano@dep.uminho.pt; Reis, Rui L., E-mail: rgreis@dep.uminho.pt

    2012-08-01

    The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in {alpha}-amylase was more notable when the starch concentration was the highest at 30 wt.%. The conjugates were resistant to the degradation by protease and lysozyme except for the conjugates with the lowest starch concentration. After 10 days of cell culture, the proliferation of osteoblast-like cells (SaOS-2) was stimulated significantly by higher fibroin compositions and the DNA synthesis on the conjugate with the highest fibroin (30 wt.%) was about two times more compared to the native chitosan. The light microscopy and the image analysis results showed that the cell area and the lengths were decreased significantly with higher fibroin/chitosan ratio. The study proved that the conjugation of fibroin and starch with the chitosan based biomaterials by the use of non-toxic reductive alkylation crosslinking significantly improved the cytocompatibility and modulated the biodegradation, respectively. - Highlights: Black-Right-Pointing-Pointer Silk fibroin, starch and chitosan conjugates were prepared by reductive alkylation. Black-Right-Pointing-Pointer The enzymatic biodegradation and the cytocompatibility of conjugates were tested. Black-Right-Pointing-Pointer The conjugate with 30% starch composition was degraded by {alpha}-amylase significantly. Black-Right-Pointing-Pointer Higher starch composition in conjugates prevented protease and lysozyme degradation. Black-Right-Pointing-Pointer Fibroin incorporation effectively increased the cell proliferation of conjugates.

  19. In vivo NMR analysis of incorporation of [2-13C] glycine into silk fibroin

    International Nuclear Information System (INIS)

    Asakura, Tetsuo; Nagashima, Mariko; Demura, Makoto; Osanai, Minoru.

    1990-01-01

    The biosynthetic mechanism of silk fibroin in silkworms, Bombyx mori, is unique because this fibrous protein composed mainly of glycine, alanine and serine is produced very rapidly in large quantity in the posterior silk glands. It is very meaningful to investigate into the biosynthesis of silk protein under nondestructive condition by in vivo NMR and C-13 labeling techniques. The sugar metabolism related to the production of silk fibroin was analyzed by monitoring the change in the C-13 labeled peaks in the NMR spectra for silkworms. In this paper, the monitoring of the 2-(C-13) glycine metabolism in Bombyx mori by the C-13 NMR in vivo is reported. In particular, the in vivo transport of glycine from the midgut to the posterior silk gland was measured, and the rate constants were determined with the course of the peak intensity in the C-13 NMR spectra. It is possible to discuss quantitatively the in vivo production of silk fibroin with these rate constants. The experiment and the results are reported. The in vivo C-13 NMR spectra of a 5 day old, 5th instar larva of Bombyx mori after the oral administration of 2-(C-13) glycine are shown. The significant increase of the peak intensity occurred. (K.I.)

  20. Novel fabrication method of the peritoneal dialysis filter using silk fibroin with urease fixation system.

    Science.gov (United States)

    Moon, Bo Mi; Choi, Myung-Jin; Sultan, Md Tipu; Yang, Jae Won; Ju, Hyung Woo; Lee, Jung Min; Park, Hyun Jung; Park, Ye Ri; Kim, Soo Hyeon; Kim, Dong Wook; Lee, Min Chae; Jeong, Ju Yeon; Lee, Ok Joo; Sung, Gun Yong; Park, Chan Hum

    2017-10-01

    During the last decade, there has been a great advance in the kidney dialysis system by wearable artificial kidney (WAK) system for end-stage renal disease patients. Uremic solute removal and water regeneration system are the most prerequisite for WAK to work properly. In this study, we designed a filtering membrane system by using immobilized urease silk fibroin filter and evaluated its comparative effectiveness with a PVDF filtering system in peritoneal dialysate regeneration system by urea removal efficacy. We evaluated this membrane's characteristic and performances by conducting SEM-EDX analyze, water-binding abilities and porosity test, removal abilities of urea, cytotoxicity assay and enzyme activity assay. Under the condition for optimization of urease, the percentage removal of urea was about 40% and 60% in 50 mg/dL urea solution by urease immobilized PVDF and silk fibroin scaffolds, respectively. The batch experimental result showed that immobilized filter removed more than 50% of urea in 50 mg/dL urea solution. In addition silk fibroin with urease filter removed 90 percent of urea in the peritoneal dialysate after 24 h filtration. We suggest that silk fibroin with urease fixation filter can be used more effectively for peritoneal dialysate regeneration system, which have hydrophilic property and prolonged enzyme activity. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2136-2144, 2017. © 2016 Wiley Periodicals, Inc.

  1. Preparation and water absorption of cross-linked chitosan/silk fibroin blend films

    International Nuclear Information System (INIS)

    Suesat, Jantip; Rujiravanit, Ratana; Jamieson, Alexander M.; Tokura, Seiichi

    2001-01-01

    Natural polymer blend films composed of chitosan and silk fibroin were prepared by varying the ratio of chitosan to silk fibroin, with and without glutaraldehyde as a crosslinking agent. The effects of the ratio of chitosan to silk fibroin and crosslinking agent on swelling behavior of the blend films were studied. For the swelling behavior, the blend films exhibited a dramatic change in the degree of swelling when immersed in acidic solutions. The degree of swelling of the films increased as the chitosan content increased; the blend film with 80% chitosan content had the maximum degree of swelling. It appeared that crosslinking had occurred in the blend films which helped the films to retain their three dimensional structure. In addition, FTIR spectra of the films showed evidence of hydrogen bonding interaction between chitosan and silk fibroin. For the effect of salt type, the films were immersed in various types of aqueous salt solutions, viz NaCl, LiCl, CaCl 2 , AlCl 3 , and FeCl 3 . The films immersed in AlCl 3 and FeCl 3 aqueous solutions gave the maximum degree of swelling. The effects of AlCl 3 and FeCl 3 concentrations on swelling behavior were also investigated. It was found that the maximum degree of swelling of the films occurred at 1.0 x 10 -2 M of AlCl 3 and FeCl 3 aqueous solutions. (author)

  2. 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

  3. 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

  4. 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

  5. Modulation and Stabilization of Silk Fibroin-Coated Oil-in-Water Emulsions

    Directory of Open Access Journals (Sweden)

    Zhong-Min Chen

    2009-01-01

    Full Text Available The purpose of this study is to prepare and characterize stable oil-in-water emulsions containing droplets coated with silk fibroin. Silk fibroin, a native edible fibrous protein originating from silkworm cocoons, was used to prepare 10 % (by mass corn oil-in-water emulsions at ambient temperature (pH=7.0, 10 mM phosphate buffer. Emulsions with relatively small mean particle diameter (d32=0.47 μm and extremely good creaming stability (>7 days could be produced at silk fibroin concentration of 1 % (by mass. The influence of pH (2–8, thermal processing (60–90 °C, 20 min, and concentration of salt (c(NaCl=0–250 mM on the properties and stability of the emulsions was analyzed using ζ-potential, particle size, and creaming stability measurements. The isoelectric point of droplets stabilized with silk fibroin was pH~4. The emulsions were stable to droplet flocculation and creaming at any pH except intermediate value (pH=4.0 when stored at room temperature, which was attributed to their relatively low ζ-potential. Their ζ-potential went from around 25 to –35 mV as the pH was increased from 2 to 8. The emulsions were also stable to thermal treatment (60 and 90 °C for 20 min, pH=3 and 7, with a slight decrease in the magnitude of ζ-potential at temperatures exceeding 60 °C. The emulsions were unstable to aggregation and creaming even at relatively low salt concentrations (c(NaCl=0–250 mM, pH=3 and 7 as a result of electrostatic screening effects. These results suggest that bulk oil stabilized with silk fibroin has improved physical stability and may provide a new way of creating functional oil products and delivery systems.

  6. AFM observation of silk fibroin on mica substrates: morphologies reflecting the secondary structures

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Kazushi; Tsuboi, Yasuyuki; Itaya, Akira

    2003-09-01

    Bombyx mori silk fibroin was fixed on mica substrates by cast of aqueous fibroin solutions, and the microscopic morphologies of the samples were revealed by means of atomic force microscopy. By adjusting the method used to prepare the solution, we succeeded in forming quasi-2-dimensional thin films in which a network of fibroin molecules developed over the substrate. The film network consisted of fibroin in a random coil structure. The morphology of the network changed after thermal or methanol treatments, which are known to convert the secondary structure of fibroin from the random coil to the {beta}-sheet type. In both of these cases, the network morphology disappeared and characteristic island-like morphologies appeared. On the other hand, temporally evolving gelation occurred in a fibroin solution due to the formation of {beta}-sheet crystals. Such islands were also observable in a specimen prepared by the cast of the gel-containing solution. Based on these results, it was concluded that the islands consist of {beta}-sheet crystals. Of particular interest is the observation that all of the islands had a common thickness value of 1.3 nm. These morphologies are discussed in terms of the secondary structure of fibroin.

  7. Acellular bi-layer silk fibroin scaffolds support tissue regeneration in a rabbit model of onlay urethroplasty.

    Directory of Open Access Journals (Sweden)

    Yeun Goo Chung

    Full Text Available Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4 (Width × Length, 1 × 2 cm(2 in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS implants (Group 2, N = 4 or urethrotomy alone (Group 3, N = 3. Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to pre-operative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome, immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (α-smooth muscle actin and SM22α and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results

  8. Acellular bi-layer silk fibroin scaffolds support tissue regeneration in a rabbit model of onlay urethroplasty.

    Science.gov (United States)

    Chung, Yeun Goo; Tu, Duong; Franck, Debra; Gil, Eun Seok; Algarrahi, Khalid; Adam, Rosalyn M; Kaplan, David L; Estrada, Carlos R; Mauney, Joshua R

    2014-01-01

    Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4) (Width × Length, 1 × 2 cm(2)) in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS) implants (Group 2, N = 4) or urethrotomy alone (Group 3, N = 3). Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to pre-operative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome), immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (α-smooth muscle actin and SM22α) and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results of this study

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

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    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.

  10. 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

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

    Science.gov (United States)

    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

  12. Control of fibroin conformation: Toward the development of a biomimetic spinning process for silk fibers

    Science.gov (United States)

    Carlson, Kimberly Ann Trabbic

    1999-09-01

    Nature has shown that silks are sophisticated structural materials with remarkable mechanical properties; however, they are produced using far milder conditions than high-performance synthetic polymer fibers. While recent advances in molecular biotechnology have taken great strides toward the production of proteinaceous biopolymers, little is known about the processing conditions needed to spin fibers with the correct microstructures and mechanical properties. It is the purpose of this research to gain a fundamental understanding about how processing conditions affect the molecular structure of a model protein biopolymer, Bombyx mori silkworm fibroin, the structural protein of cocoon silk. Fibers of B. mori fibroin were wet spun from 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) into a methanol coagulation bath. X-ray fiber diffraction and quantitative Raman spectroscopy were used to determine that both naturally- and synthetically-spun fibers contain a high degree of beta-sheet (~50%). Fibers subjected to a post-spinning draw exhibited a preferential molecular alignment parallel to the fiber axis resulting in increased strength, stiffness, and extensibility. Fibers with microstructures and mechanical properties most similar to those of naturally-spun fibers were reproduced in synthetically-spun fibers with a draw ratio of 3.5. The transformation of helical fibroin in HFIP to beta-sheet sheet fibroin in synthetically-spun fibers was determined to be caused by the methanol coagulation bath. The kinetics beta-sheet fibroin crystallization from aqueous solution was investigated by monitoring the sigmoidal progression of gel formation using turbidity and Raman spectroscopy. Gelation kinetics were evaluated by measuring lag time, maximum gelation rate, and optical density to determine the effects of protein concentration, detergent concentration (nucleating agent), headgroup chemistry, ionic strength, pH, and temperature. An optimal molar ratio between SDS and fibroin (100

  13. Modified silk fibroin scaffolds with collagen/decellularized pulp for bone tissue engineering in cleft palate: Morphological structures and biofunctionalities

    International Nuclear Information System (INIS)

    Sangkert, Supaporn; Meesane, Jirut; Kamonmattayakul, Suttatip; Chai, Wen Lin

    2016-01-01

    Cleft palate is a congenital malformation that generates a maxillofacial bone defect around the mouth area. The creation of performance scaffolds for bone tissue engineering in cleft palate is an issue that was proposed in this research. Because of its good biocompatibility, high stability, and non-toxicity, silk fibroin was selected as the scaffold of choice in this research. Silk fibroin scaffolds were prepared by freeze-drying before immerging in a solution of collagen, decellularized pulp, and collagen/decellularized pulp. Then, the immersed scaffolds were freeze-dried. Structural organization in solution was observed by Atomic Force Microscope (AFM). The molecular organization of the solutions and crystal structure of the scaffolds were characterized by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD), respectively. The weight increase of the modified scaffolds and the pore size were determined. The morphology was observed by a scanning electron microscope (SEM). Mechanical properties were tested. Biofunctionalities were considered by seeding osteoblasts in silk fibroin scaffolds before analysis of the cell proliferation, viability, total protein assay, and histological analysis. The results demonstrated that dendrite structure of the fibrils occurred in those solutions. Molecular organization of the components in solution arranged themselves into an irregular structure. The fibrils were deposited in the pores of the modified silk fibroin scaffolds. The modified scaffolds showed a beta-sheet structure. The morphological structure affected the mechanical properties of the silk fibroin scaffolds with and without modification. Following assessment of the biofunctionalities, the modified silk fibroin scaffolds could induce cell proliferation, viability, and total protein particularly in modified silk fibroin with collagen/decellularized pulp. Furthermore, the histological analysis indicated that the cells could adhere in modified silk fibroin

  14. Orientational structure formation of silk fibroin with anisotropic properties in solutions

    International Nuclear Information System (INIS)

    Kholmuminov, A.A.

    2008-06-01

    Key words:silk fibroin, dissolution, solution's model systems, gelation, orientational crystallization, optical polarization, longitudinal stream, α - β transition, structure formation, phase transformations, relaxation, anisotropy of swelling and desorption, thermo- and biodegradation. Subjects of the inquiry: silk fibroin is the main subject of investigation. Fibroin's solutions were obtained on the base of water and organic solvents, containing salts. Comparative investigations were carried out by using biosolution - secretion of silkworm, solutions of silk sericin, cotton cellulose, methylcellulose, polystyrene and (co) polycrylonitrile. Aim of the inquiry: the elucidation of the regularities of silk fibroin anisotropic structures formation in the direct generation of orientational ordering in solutions taking into account of influences of its the molecular structures, configuration information, α - β conformational transformations, and development jointly using polarization-optical and hydrodynamic methods to control of structure formation. And also definition of possibility fields for use biopolymers anisotropic structure formation principles. Method of inquiry: birefringence, dispersion optical rotation, circular dichroism, polarization- ultramicroscope, ultracentrifuge, viscosimetry, potentiometry, differential thermal analysis, chromatography, x-ray analysis, spectroscopy. The results achieved and their novelty: the physical regularity amorphous-crystalline fibroin dissolutions in salt-containing solvents based on chains melting, distribution and redistribution were recognized; fibroin statistical parameters, molecular-mass and conformational characteristics were established; It was shown that fibroin molecules turned into fully uncoiled and oriented state with the breakdown decay of α-spiral chain sections by I type phase transition mechanism, but in oriented state with α-spiral conservation by II type transition; the presence of longitudinal field

  15. Effect of the sterilization method on the properties of Bombyx mori silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    George, Karina A. [Queensland Eye Institute, 41 Annerley Road, South Brisbane, Queensland 4101 (Australia); Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059 (Australia); Shadforth, Audra M.A. [Queensland Eye Institute, 41 Annerley Road, South Brisbane, Queensland 4101 (Australia); Chirila, Traian V., E-mail: traian.chirila@qei.org.au [Queensland Eye Institute, 41 Annerley Road, South Brisbane, Queensland 4101 (Australia); Australian Institute of Bioengineering and Nanotechnology, University of Queensland, St Lucia, 4072 (Australia); Faculty of Health Sciences, University of Queensland, Herston, Queensland 4006 (Australia); Faculty of Science and Engineering, Queensland University of Technology, Brisbane, Queensland 4001 (Australia); Laurent, Matthieu J. [Queensland Eye Institute, 41 Annerley Road, South Brisbane, Queensland 4101 (Australia); Ecole Superieure d' Ingenieurs de Luminy (ESIL), Universite de la Mediterranee Aix-Marseille II, Luminy case 925 13288, Marseille, Cedex 09 (France); Stephenson, Sally-Anne [Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059 (Australia); Faculty of Health, Queensland University of Technology, Brisbane, Queensland 4001 (Australia); Edwards, Grant A. [Australian Institute of Bioengineering and Nanotechnology, University of Queensland, St Lucia, 4072 (Australia); Madden, Peter W. [Queensland Eye Institute, 41 Annerley Road, South Brisbane, Queensland 4101 (Australia); Faculty of Health Sciences, University of Queensland, Herston, Queensland 4006 (Australia); and others

    2013-03-01

    We have compared the effects of different sterilization techniques on the properties of Bombyx mori silk fibroin thin films with the view to subsequent use for corneal tissue engineering. The transparency, tensile properties, corneal epithelial cell attachment and degradation of the films were used to evaluate the suitability of certain sterilization techniques including gamma-irradiation (in air or nitrogen), steam treatment and immersion in aqueous ethanol. The investigations showed that gamma-irradiation, performed either in air or in a nitrogen atmosphere, did not significantly alter the properties of films. The films sterilized by gamma-irradiation or by immersion in ethanol had a transparency greater than 98% and tensile properties comparable to human cornea and amniotic membrane, the materials of choice in the reconstruction of ocular surface. Although steam-sterilization produced stronger, stiffer films, they were less transparent, and cell attachment was affected by the variable topography of these films. It was concluded that gamma-irradiation should be considered to be the most suitable method for the sterilization of silk fibroin films, however, the treatment with ethanol is also an acceptable method. - Highlights: Black-Right-Pointing-Pointer The effects of four methods of sterilization on the properties of silk fibroin films were investigated. Black-Right-Pointing-Pointer Steam treatment leads to stiffer films but to lower transparency and variable surface topography. Black-Right-Pointing-Pointer Degradation of fibroin is enhanced in the films that were gamma-irradiated. Black-Right-Pointing-Pointer The effects on mechanical properties are explained through changes in both primary and secondary structure of fibroin. Black-Right-Pointing-Pointer Gamma-irradiation and immersion in aqueous ethanol are suggested as preferred methods of sterilization.

  16. Effect of the sterilization method on the properties of Bombyx mori silk fibroin films

    International Nuclear Information System (INIS)

    George, Karina A.; Shadforth, Audra M.A.; Chirila, Traian V.; Laurent, Matthieu J.; Stephenson, Sally-Anne; Edwards, Grant A.; Madden, Peter W.

    2013-01-01

    We have compared the effects of different sterilization techniques on the properties of Bombyx mori silk fibroin thin films with the view to subsequent use for corneal tissue engineering. The transparency, tensile properties, corneal epithelial cell attachment and degradation of the films were used to evaluate the suitability of certain sterilization techniques including gamma-irradiation (in air or nitrogen), steam treatment and immersion in aqueous ethanol. The investigations showed that gamma-irradiation, performed either in air or in a nitrogen atmosphere, did not significantly alter the properties of films. The films sterilized by gamma-irradiation or by immersion in ethanol had a transparency greater than 98% and tensile properties comparable to human cornea and amniotic membrane, the materials of choice in the reconstruction of ocular surface. Although steam-sterilization produced stronger, stiffer films, they were less transparent, and cell attachment was affected by the variable topography of these films. It was concluded that gamma-irradiation should be considered to be the most suitable method for the sterilization of silk fibroin films, however, the treatment with ethanol is also an acceptable method. - Highlights: ► The effects of four methods of sterilization on the properties of silk fibroin films were investigated. ► Steam treatment leads to stiffer films but to lower transparency and variable surface topography. ► Degradation of fibroin is enhanced in the films that were gamma-irradiated. ► The effects on mechanical properties are explained through changes in both primary and secondary structure of fibroin. ► Gamma-irradiation and immersion in aqueous ethanol are suggested as preferred methods of sterilization.

  17. Structural and thermal properties of γ – irradiated Bombyx mori silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Madhukumar, R.; Asha, S.; Rao, B. Lakshmeesha; Shivananda, C. S.; Harish, K. V.; Sangappa, E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore - 574199 (India); Sarojini, B. K. [Department of Studies in Chemistry, Mangalore University, Mangalagangotri, Mangalore - 574199 (India); Somashekar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore - 570006 (India)

    2015-06-24

    The gamma radiation-induced change in structural and thermal properties of Bombyx mori silk fibroin films were investigated and have been correlated with the applied radiation doses. Irradiation of samples were carried out in dry air at room temperature using Co-60 source, and radiation doses are in the range of 0 - 300 kGy. Structural and thermal properties of the irradiated silk films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) and compared with unirradiated sample. Interesting results are discussed in this report.

  18. Fabrication of Antibacterial Wound Dressings from Silk Fibroin and Silver Nano particles

    International Nuclear Information System (INIS)

    Uttayarat, P.; Jetawattana, S.; Suwanmala, P.; Eamsiri, J.; Pongpat, S.

    2011-06-01

    Full text: Patients with burn wounds that cover large body surface area are susceptible to infection which can lead to fatality. Wound dressings or skin grafts are needed to cover the wound during the regeneration of new skin tissue. The aim of this research is to fabricate antibacterial wound dressings from silk fibroin derived from the natural silk cocoon and silver nanoparticles (AgNPs) prepared by gamma irradiation. Fibroin mats composed of nonwoven fibers with diameter of 670± 11.5 nm were fabricated by electro spinning. Using gamma irradiation, the starting silver nitrate solution was reduced to colloidal AgNPs. The fibroin mats were coated with AgNPs at various AgNP concentration and then evaluated for their antibacterial property by disc diffusion test. The concentration of colloidal AgNP solution ≤ 1 mM was found to be as sufficient in inhibiting the growth of Pseudomonas aeruginosa and Staphylococcus aureus as commercial wound dressings embedded with silver ions. These results demonstrate that electro spun fibroin mats coated with AgNPs exhibite antibacterial property and can be further developed for the treatment of burn wounds

  19. Preparation and water absorption of cross-linked chitosan/silk fibroin blend films

    Energy Technology Data Exchange (ETDEWEB)

    Suesat, Jantip; Rujiravanit, Ratana [Chulalongkorn University, The Petroleum and Petrochemical College, Bangkok (Thailand); Jamieson, Alexander M. [Case Western Reserve Univ., Department of Macromolecular Science, Cleveland (United States); Tokura, Seiichi [Kansai Univ., Faculty of Engineering, Osaka (Japan)

    2001-03-01

    Natural polymer blend films composed of chitosan and silk fibroin were prepared by varying the ratio of chitosan to silk fibroin, with and without glutaraldehyde as a crosslinking agent. The effects of the ratio of chitosan to silk fibroin and crosslinking agent on swelling behavior of the blend films were studied. For the swelling behavior, the blend films exhibited a dramatic change in the degree of swelling when immersed in acidic solutions. The degree of swelling of the films increased as the chitosan content increased; the blend film with 80% chitosan content had the maximum degree of swelling. It appeared that crosslinking had occurred in the blend films which helped the films to retain their three dimensional structure. In addition, FTIR spectra of the films showed evidence of hydrogen bonding interaction between chitosan and silk fibroin. For the effect of salt type, the films were immersed in various types of aqueous salt solutions, viz NaCl, LiCl, CaCl{sub 2}, AlCl{sub 3}, and FeCl{sub 3}. The films immersed in AlCl{sub 3} and FeCl{sub 3} aqueous solutions gave the maximum degree of swelling. The effects of AlCl{sub 3} and FeCl{sub 3} concentrations on swelling behavior were also investigated. It was found that the maximum degree of swelling of the films occurred at 1.0 x 10{sup -2} M of AlCl{sub 3} and FeCl{sub 3} aqueous solutions. (author)

  20. Facile fabrication of the porous three-dimensional regenerated silk fibroin scaffolds

    International Nuclear Information System (INIS)

    Cao, Zhengbing; Wen, Jianchuan; Yao, Jinrong; Chen, Xin; Ni, Yusu; Shao, Zhengzhong

    2013-01-01

    In the present work, we report a new facile method to fabricate porous three-dimensional regenerated silk fibroin (RSF) scaffolds through n-butanol- and freezing-induced conformation transition and phase separation. The effects of RSF concentration, freezing temperature and n-butanol addition on the microstructure, the secondary structures of silk fibroin and apparent mechanical properties of the RSF scaffolds were investigated by SEM, 13 C CP-MAS NMR spectra and mechanical testing, respectively. By adjusting the RSF concentration and n-butanol addition, the pore size of the scaffold could be controlled in the range from of 10 μm to 350 μm with 84%–98% of porosity. The tensile strength of the wet scaffold reached the maximum of 755.2 ± 33.6 kPa when the concentration of RSF solution was increased to 15% w/w. Moreover, post-treatment with ethanol further induced conformation transition of RSF from random coil or helix to β-sheet. The porous scaffolds prepared by this facile and energy-saving method with good biocompatibility will have great potential for application in tissue engineering. Highlights: • A new facile and energy-saving method to fabricate porous silk fibroin scaffolds; • Freeze-drying step (a typical high energy consuming process) is unnecessary; • Morphology and mechanical properties of scaffolds were easily controlled; • Ethanol post-treatment can be used to tune the degradation behavior

  1. Chitosan-functionalized silk fibroin 3D scaffold for keratocyte culture.

    Science.gov (United States)

    Guan, Linan; Tian, Pei; Ge, Hongyan; Tang, Xianling; Zhang, Hong; Du, Lingling; Liu, Ping

    2013-10-01

    The goal of this study was to evaluate the potential suitability of an artificial membrane composed of silk fibroin (SF) functionalized by different ratios of chitosan (CS) as a substrate for the stroma of the cornea. Keratocytes were cultured on translucent membranes made of SF and CS with different ratios. The biophysical properties of the silk fibroin and chitosan (SF/CS) membrane were examined. The SF/CS showed tensile strengths that increased as the CS concentration increased, but the physical and mechanical properties of chitosan-functionalized silk fibroin scaffolds weakened significantly compared with those of native corneas. The resulting cell scaffolds were evaluated using western blot in addition to light and electron microscopy. The cell attachment and proliferation on the scaffold were similar to those on a plastic plate. Keratocytes cultured in serum on SF/CS exhibited stellate morphology along with a marked increase in the expression of keratocan compared with identical cultures on tissue culture plastics. The biocompatibility was tested by transplanting the acellular membrane into rabbit corneal stromal pockets. There was no inflammatory complication detected at any time point on the macroscopic level. Taken together, these results indicate that SF/CS holds promise as a substrate for corneal reconstruction.

  2. 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.

  3. In vitro and in vivo research on using Antheraea pernyi silk fibroin as tissue engineering tendon scaffolds

    International Nuclear Information System (INIS)

    Fang Qian; Chen Denglong; Yang Zhiming; Li Min

    2009-01-01

    In this paper, the feasibility of using Antheraea pernyi silk fibroin as tissue engineering tendon scaffold was investigated in vitro and in vivo, respectively, utilizing tenocytes and animal model. The animal model used here was an adult New Zealand White rabbit with a 15-mm gap defect in both sides of the Achilles tendon. The Achilles tendon defects in one side of hind legs were repaired using the braided A. pernyi silk fibroin scaffold in experimental group (n = 24), while the other side left untreated as negative group (n = 24). The recovery of the defect tendons were evaluated postoperatively at the 2nd, 6th, 12th, and 16th week using macroscopic, histological, immunohistochemical, scanning electron micrograph and biomechanical test techniques. In vitro results examined by scanning electron micrograph showed that A. pernyi silk fibroin promote the adhesion and propagation of the tenocytes. In vivo, at 16 weeks after implantation, morphological results showed that neo-tendons were formed, and bundles of collagen fibers in the neo-tendons were uniform and well oriented. Immunohistochemical results showed that collagen type in the regenerated tendons was predominantly type I. The maximum load of regenerated tendon at 16 weeks reached 55.46% of the normal tendon values. Preliminary, we concluded that A. pernyi silk fibroin promoted the recovery of Achilles tendon defect of rabbit and the application of A. pernyi silk fibroin as tissue engineering tendon scaffold is feasible.

  4. In vitro and in vivo research on using Antheraea pernyi silk fibroin as tissue engineering tendon scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Fang Qian [College of Life Sciences, Fujian Normal University, Fuzhou, Fujian350108 (China); Chen Denglong [College of Chemistry and Materials Sciences, Fujian Normal University, Fuzhou, Fujian350108 (China); Yang Zhiming [Division of Stem Cell and Tissue Engineering, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041 (China); Li Min, E-mail: mli@fjnu.edu.cn [College of Life Sciences, Fujian Normal University, Fuzhou, Fujian350108 (China)

    2009-06-01

    In this paper, the feasibility of using Antheraea pernyi silk fibroin as tissue engineering tendon scaffold was investigated in vitro and in vivo, respectively, utilizing tenocytes and animal model. The animal model used here was an adult New Zealand White rabbit with a 15-mm gap defect in both sides of the Achilles tendon. The Achilles tendon defects in one side of hind legs were repaired using the braided A. pernyi silk fibroin scaffold in experimental group (n = 24), while the other side left untreated as negative group (n = 24). The recovery of the defect tendons were evaluated postoperatively at the 2nd, 6th, 12th, and 16th week using macroscopic, histological, immunohistochemical, scanning electron micrograph and biomechanical test techniques. In vitro results examined by scanning electron micrograph showed that A. pernyi silk fibroin promote the adhesion and propagation of the tenocytes. In vivo, at 16 weeks after implantation, morphological results showed that neo-tendons were formed, and bundles of collagen fibers in the neo-tendons were uniform and well oriented. Immunohistochemical results showed that collagen type in the regenerated tendons was predominantly type I. The maximum load of regenerated tendon at 16 weeks reached 55.46% of the normal tendon values. Preliminary, we concluded that A. pernyi silk fibroin promoted the recovery of Achilles tendon defect of rabbit and the application of A. pernyi silk fibroin as tissue engineering tendon scaffold is feasible.

  5. 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.

  6. Molecular architecture of silk fibroin of Indian golden silkmoth, Antheraea assama.

    Science.gov (United States)

    Gupta, Adarsh K; Mita, Kazuei; Arunkumar, Kallare P; Nagaraju, Javaregowda

    2015-08-03

    The golden silk spun by Indian golden silkmoth Antheraea assama, is regarded for its shimmering golden luster, tenacity and value as biomaterial. This report describes the gene coding for golden silk H-fibroin (AaFhc), its expression, full-length sequence and structurally important motifs discerning the underlying genetic and biochemical factors responsible for its much sought-after properties. The coding region, with biased isocodons, encodes highly repetitious crystalline core, flanked by a pair of 5' and 3' non-repetitious ends. AaFhc mRNA expression is strictly territorial, confined to the posterior silk gland, encoding a protein of size 230 kDa, which makes homodimers making the elementary structural units of the fibrous core of the golden silk. Characteristic polyalanine repeats that make tight β-sheet crystals alternate with non-polyalanine repeats that make less orderly antiparallel β-sheets, β-turns and partial α-helices. Phylogenetic analysis of the conserved N-terminal amorphous motif and the comparative analysis of the crystalline region with other saturniid H-fibroins reveal that AaFhc has longer, numerous and relatively uniform repeat motifs with lower serine content that assume tighter β-crystals and denser packing, which are speculated to be responsible for its acclaimed properties of higher tensile strength and higher refractive index responsible for golden luster.

  7. Dissolution and regeneration of non-mulberry Eriogyna Pyretorum silk fibroin

    Science.gov (United States)

    Guo, Yuhang; Li, Xiufang; Zhang, Qiang; Yan, Shuqin; You, Renchuan

    2017-10-01

    Protein-based materials have been actively pursued as biomaterials because of their nontoxicity, biocompatibility and biodegradability. In this work, we demonstrated the potential of Eriogyna pyretorum silk fibroin (ESF), a non-mulberry silk protein, as biomaterials. The degummed ESF fibers could be dissolved completely by Ca(NO3)2/H2O/C2H5OH solution to produce regenerated ESF. The solubility was strongly dependent on the addition of C2H5OH, heating temperature and dissolving time. α-helix and random coil are main molecular conformation in aqueous ESF solution. The sol-gel transition behavior of regenerated ESF was also studied, indicating that the conformational transition of regenerated ESF from random coil/α-helix to β-sheet during gelation. Especially, ESF showed more rapid gelation than mulberry silk fibroin (BSF). Consequently, the gelation rate of BSF could be controlled ranging from tens of minutes to days by changing the ESF ratio, providing useful options for the fabrication of silk hydrogels. Water-stable regenerated ESF film could be achieved by using aqueous ethanol to induce structural transition. Tensile tests showed that the ESF films have a dry strength of approximate 31.0 MPa and a wet strength of approximate 3.3 MPa. This study provides new opportunities as an alternative natural protein material for biomedical applications.

  8. Microwave assisted synthesis of luminescent carbonaceous nanoparticles from silk fibroin for bioimaging.

    Science.gov (United States)

    Gao, Hongzhi; Teng, Choon Peng; Huang, Donghong; Xu, Wanqing; Zheng, Chaohui; Chen, Yisong; Liu, Minghuan; Yang, Da-Peng; Lin, Ming; Li, Zibiao; Ye, Enyi

    2017-11-01

    Bombyx mori silk as a natural protein based biopolymer with high nitrogen content, is abundant and sustainable because of its mass product all over the world per year. In this study, we developed a facile and fast microwave-assisted synthesis of luminescent carbonaceous nanoparticles using Bombyx mori silk fibroin and silk solution as the precursors. As a result, the obtained carbonaceous nanoparticles exhibit a photoluminescence quantum yield of ~20%, high stability, low cytotoxicity, high biocompatibility. Most importantly, we successfully demonstrated bioimaging using these luminescent carbonaceous nanoparticles with excitation dependent luminescence. In addition, the microwave-assisted hydrothermal method can be extended to convert other biomass into functional nanomaterials. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. 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.

  10. Incorporation of Human Recombinant Tropoelastin into Silk Fibroin Membranes with the View to Repairing Bruch’s Membrane

    Directory of Open Access Journals (Sweden)

    Audra M. A. Shadforth

    2015-09-01

    Full Text Available Bombyx mori silk fibroin membranes provide a potential delivery vehicle for both cells and extracellular matrix (ECM components into diseased or injured tissues. We have previously demonstrated the feasibility of growing retinal pigment epithelial cells (RPE on fibroin membranes with the view to repairing the retina of patients afflicted with age-related macular degeneration (AMD. The goal of the present study was to investigate the feasibility of incorporating the ECM component elastin, in the form of human recombinant tropoelastin, into these same membranes. Two basic strategies were explored: (1 membranes prepared from blended solutions of fibroin and tropoelastin; and (2 layered constructs prepared from sequentially cast solutions of fibroin, tropoelastin, and fibroin. Optimal conditions for RPE attachment were achieved using a tropoelastin-fibroin blend ratio of 10 to 90 parts by weight. Retention of tropoelastin within the blend and layered constructs was confirmed by immunolabelling and Fourier-transform infrared spectroscopy (FTIR. In the layered constructs, the bulk of tropoelastin was apparently absorbed into the initially cast fibroin layer. Blend membranes displayed higher elastic modulus, percentage elongation, and tensile strength (p < 0.01 when compared to the layered constructs. RPE cell response to fibroin membranes was not affected by the presence of tropoelastin. These findings support the potential use of fibroin membranes for the co-delivery of RPE cells and tropoelastin.

  11. Activation of the Ubiquitin Proteasome Pathway by Silk Fibroin Modified Chitosan Nanoparticles in Hepatic Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ming-Hui Yang

    2015-01-01

    Full Text Available Silk fibroin (SF is a protein with bulky hydrophobic domains and can be easily purified as sericin-free silk-based biomaterial. Silk fibroin modified chitosan nanoparticle (SF-CSNP, a biocompatible material, has been widely used as a potential drug delivery system. Our current investigation studied the bio-effects of the SF-CSNP uptake by liver cells. In this experiment, the characterizations of SF-CSNPs were measured by particle size analysis and protein assay. The average size of the SF-CSNP was 311.9 ± 10.7 nm, and the average zeta potential was +13.33 ± 0.3 mV. The SF coating on the SF-CSNP was 6.27 ± 0.17 μg/mL. Moreover, using proteomic approaches, several proteins involved in the ubiquitin proteasome pathway were identified by analysis of differential protein expressions of HepG2 cell uptake the SF-CSNP. Our experimental results have demonstrated that the SF-CSNP may be involved in liver cancer cell survival and proliferation.

  12. 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.

  13. 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

  14. 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

  15. Influence of electron irradiation on the structural and thermal properties of silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Asha, S.; Sangappa,; Sanjeev, Ganesh, E-mail: ganeshanjeev@rediffmail.com [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore - 574 199 (India)

    2015-06-24

    Radiation-induced changes in Bombyx mori silk fibroin (SF) films under electron irradiation were investigated and correlated with dose. SF films were irradiated in air at room temperature using 8 MeV electron beam in the range 0-150 kGy. Various properties of the irradiated SF films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Electron irradiation was found to induce changes in the physical and thermal properties, depending on the radiation dose.

  16. Comparative Study of Ultrasonication-Induced and Naturally Self-Assembled Silk Fibroin-Wool Keratin Hydrogel Biomaterials.

    Science.gov (United States)

    Vu, Trang; Xue, Ye; Vuong, Trinh; Erbe, Matthew; Bennet, Christopher; Palazzo, Ben; Popielski, Lucas; Rodriguez, Nelson; Hu, Xiao

    2016-09-07

    This study reports the formation of biocompatible hydrogels using protein polymers from natural silk cocoon fibroins and sheep wool keratins. Silk fibroin protein contains β-sheet secondary structures, allowing for the formation of physical cross-linkers in the hydrogels. Comparative studies were performed on two groups of samples. In the first group, ultrasonication was used to induce a quick gelation of a protein aqueous solution, enhancing the ability of Bombyx mori silk fibroin chains to quickly entrap the wool keratin protein molecules homogenously. In the second group, silk/keratin mixtures were left at room temperature for days, resulting in naturally-assembled gelled solutions. It was found that silk/wool blended solutions can form hydrogels at different mixing ratios, with perfectly interconnected gel structure when the wool content was less than 30 weight percent (wt %) for the first group (ultrasonication), and 10 wt % for the second group (natural gel). Differential scanning calorimetry (DSC) and temperature modulated DSC (TMDSC) were used to confirm that the fibroin/keratin hydrogel system was well-blended without phase separation. Fourier transform infrared spectroscopy (FTIR) was used to investigate the secondary structures of blended protein gels. It was found that intermolecular β-sheet contents significantly increase as the system contains more silk for both groups of samples, resulting in stable crystalline cross-linkers in the blended hydrogel structures. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the samples' characteristic morphology on both micro- and nanoscales, which showed that ultrasonic waves can significantly enhance the cross-linker formation and avoid phase separation between silk and keratin molecules in the blended systems. With the ability to form cross-linkages non-chemically, these silk/wool hydrogels may be economically useful for various biomedical applications, thanks to the

  17. Comparative Study of Ultrasonication-Induced and Naturally Self-Assembled Silk Fibroin-Wool Keratin Hydrogel Biomaterials

    Directory of Open Access Journals (Sweden)

    Trang Vu

    2016-09-01

    Full Text Available This study reports the formation of biocompatible hydrogels using protein polymers from natural silk cocoon fibroins and sheep wool keratins. Silk fibroin protein contains β-sheet secondary structures, allowing for the formation of physical cross-linkers in the hydrogels. Comparative studies were performed on two groups of samples. In the first group, ultrasonication was used to induce a quick gelation of a protein aqueous solution, enhancing the ability of Bombyx mori silk fibroin chains to quickly entrap the wool keratin protein molecules homogenously. In the second group, silk/keratin mixtures were left at room temperature for days, resulting in naturally-assembled gelled solutions. It was found that silk/wool blended solutions can form hydrogels at different mixing ratios, with perfectly interconnected gel structure when the wool content was less than 30 weight percent (wt % for the first group (ultrasonication, and 10 wt % for the second group (natural gel. Differential scanning calorimetry (DSC and temperature modulated DSC (TMDSC were used to confirm that the fibroin/keratin hydrogel system was well-blended without phase separation. Fourier transform infrared spectroscopy (FTIR was used to investigate the secondary structures of blended protein gels. It was found that intermolecular β-sheet contents significantly increase as the system contains more silk for both groups of samples, resulting in stable crystalline cross-linkers in the blended hydrogel structures. Scanning electron microscopy (SEM and atomic force microscopy (AFM were used to analyze the samples’ characteristic morphology on both micro- and nanoscales, which showed that ultrasonic waves can significantly enhance the cross-linker formation and avoid phase separation between silk and keratin molecules in the blended systems. With the ability to form cross-linkages non-chemically, these silk/wool hydrogels may be economically useful for various biomedical applications

  18. Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics.

    Science.gov (United States)

    Kim, Dae-Hyeong; Viventi, Jonathan; Amsden, Jason J; Xiao, Jianliang; Vigeland, Leif; Kim, Yun-Soung; Blanco, Justin A; Panilaitis, Bruce; Frechette, Eric S; Contreras, Diego; Kaplan, David L; Omenetto, Fiorenzo G; Huang, Yonggang; Hwang, Keh-Chih; Zakin, Mitchell R; Litt, Brian; Rogers, John A

    2010-06-01

    Electronics that are capable of intimate, non-invasive integration with the soft, curvilinear surfaces of biological tissues offer important opportunities for diagnosing and treating disease and for improving brain/machine interfaces. This article describes a material strategy for a type of bio-interfaced system that relies on ultrathin electronics supported by bioresorbable substrates of silk fibroin. Mounting such devices on tissue and then allowing the silk to dissolve and resorb initiates a spontaneous, conformal wrapping process driven by capillary forces at the biotic/abiotic interface. Specialized mesh designs and ultrathin forms for the electronics ensure minimal stresses on the tissue and highly conformal coverage, even for complex curvilinear surfaces, as confirmed by experimental and theoretical studies. In vivo, neural mapping experiments on feline animal models illustrate one mode of use for this class of technology. These concepts provide new capabilities for implantable and surgical devices.

  19. In vitro study on silk fibroin textile structure for anterior cruciate ligament regeneration.

    Science.gov (United States)

    Farè, Silvia; Torricelli, Paola; Giavaresi, Gianluca; Bertoldi, Serena; Alessandrino, Antonio; Villa, Tomaso; Fini, Milena; Tanzi, Maria Cristina; Freddi, Giuliano

    2013-10-01

    A novel hierarchical textile structure made of silk fibroin from Bombyx mori capable of matching the mechanical performance requirements of anterior cruciate ligament (ACL) and in vitro cell ingrowth is described. This sericin-free, Silk Fibroin Knitted Sheath with Braided Core (SF-KSBC) structure was fabricated using available textile technologies. Micro-CT analysis confirmed that the core was highly porous and had a higher degree of interconnectivity than that observed for the sheath. The in vivo cell colonization of the scaffolds is thus expected to penetrate even the internal parts of the structure. Tensile mechanical tests demonstrated a maximum load of 1212.4±56.4 N (under hydrated conditions), confirming the scaffold's suitability for ACL reconstruction. The absence of cytotoxic substances in the extracts of the SF-KSBC structure in culture medium was verified by in vitro tests with L929 fibroblasts. In terms of extracellular matrix production, Human Periodontal Ligament Fibroblasts (HPdLFs) cultured in direct contact with SF-KSBC, compared to control samples, demonstrated an increased secretion of aggrecan (PG) and fibronectin (FBN) at 3 and 7 days of culture, and no change in IL-6 and TNF-α secretion. Altogether, the outcomes of this investigation confirm the significant utility of this novel scaffold for ACL tissue regeneration. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Smooth silk fibroin nanofilm deposited by 1064-nm pulsed laser beam from an opaque target

    International Nuclear Information System (INIS)

    Nozaki, R.; Nakayama, S.; Senna, M.

    2013-01-01

    In an attempt to prepare smooth nanostructured thin films of silk fibroin (SF) by near-infrared (NIR) pulsed laser deposition, an opaque target was prepared from an emulsified aqueous solution of SF. Upon irradiation of 1064-nm pulsed laser beam at its fluence 5 J/cm 2 , a thin film of SF was deposited on the Si(100) substrate with its root-mean-square surface roughness, 0.37 nm, smoother than those obtained from a compressed target of SF powders by approximately an order of magnitude. The attainment of an extra-smooth film from the opaque target was discussed in terms of multiple Mie scattering of the incident NIR beam, leading to an increase in the plasma density, intensified optical breakdown, ablation of better dispersed SF molecular units, and a film with more intensive intermolecular cross-linking. - Highlights: • Thin film of silk fibroin with its RMS surface roughness, R rms , 0.37 nm was obtained. • The use of a target from an emulsified solution of SF was the key issue. • Mechanism involved was elucidated in terms of enhanced Mie scattering

  1. Fibroin and sericin from Bombyx mori silk stimulate cell migration through upregulation and phosphorylation of c-Jun.

    Directory of Open Access Journals (Sweden)

    Celia Martínez-Mora

    Full Text Available Wound healing is a biological process directed to the restoration of tissue that has suffered an injury. An important phase of wound healing is the generation of a basal epithelium able to wholly replace the epidermis of the wound. A broad range of products derived from fibroin and sericin from Bombyx mori silk are used to stimulate wound healing. However, so far the molecular mechanism underlying this phenomenon has not been elucidated. The aim of this work was to determine the molecular basis underlying wound healing properties of silk proteins using a cell model. For this purpose, we assayed fibroin and sericin in a wound healing scratch assay using MDA-MB-231 and Mv1Lu cells. Both proteins stimulated cell migration. Furthermore, treatment with sericin and fibroin involved key factors of the wound healing process such as upregulation of c-Jun and c-Jun protein phosphorylation. Moreover, fibroin and sericin stimulated the phosphorylation of ERK 1/2 and JNK 1/2 kinases. All these experiments were done in the presence of specific inhibitors for some of the cell signalling pathways referred above. The obtained results revealed that MEK, JNK and PI3K pathways are involved in fibroin and sericin stimulated cells migration. Inhibition of these three kinases prevented c-Jun upregulation and phosphorylation by fibroin or sericin. Fibroin and sericin were tested in the human keratinocyte cell line, HaCaT, with similar results. Altogether, our results showed that fibroin and sericin initiate cell migration by activating the MEK, JNK and PI3K signalling pathways ending in c-Jun activation.

  2. Preparation and characterization of novel nanocomposite films formed from silk fibroin and nano-TiO2.

    Science.gov (United States)

    Feng, Xin-Xing; Zhang, Li-Li; Chen, Jian-Yong; Guo, Yu-Hai; Zhang, Hua-Peng; Jia, Chang-Ian

    2007-01-30

    This paper describes the synthesis and characterization of new regenerated silk fibroin (SF)/nano-TiO(2) composite films. The preparation method, based on the sol-gel technique using butyl titanate as oxide precursor, could avoid reagglomeration of the prepared nanoparticles. Samples were characterized mainly by X-ray diffraction (XRD), ultra-violet (UV) spectroscopy, atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The UV and AFM results indicated that TiO(2) nanoparticles could be well dispersed inside the SF film, and the size of TiO(2) was about 80nm. The XRD and FT-IR analysis implied that the formation of nano-TiO(2) particles may induce the conformational transition of silk fibroin to a typical Silk II structure partly with the increasing of crystallinity in the composite films. Compared to the pure SF films, the mechanical and thermal properties of composite films were improved, and the solubility in water was decreased due to the conformational transition of silk fibroin to Silk II structure.

  3. Surface modification and properties of Bombyx mori silk fibroin films by antimicrobial peptide

    International Nuclear Information System (INIS)

    Bai Liqiang; Zhu Liangjun; Min Sijia; Liu Lin; Cai Yurong; Yao Juming

    2008-01-01

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH 2 )-NGIVKAGPAIAVLGEAAL-CONH 2 , using the carbodiimide chemistry method. In order to avoid the dissolution of films during the modification procedure, the SFFs were first treated with 60% (v/v) ethanol aqueous solution, resulting a structural transition from unstable silk I to silk II. The investigation of modification conditions showed that the surface-modified SFFs had the satisfied antimicrobial activity and durability when they were activated by EDC.HCl/NHS solution followed by a treatment in CB peptide/PBS buffer (pH 6.5 or 8) solution at ambient temperature for 2 h. Moreover, the surface-modified SFFs showed the smaller contact angle due to the hydrophilic antimicrobial peptides coupled on the film surface, which is essential for the cell adhesion and proliferation. AFM results indicated that the surface roughness of SFFs was considerably increased after the modification by the peptides. The elemental composition analysis results also suggested that the peptides were tightly coupled to the surface of SFFs. This approach may provide a new option to engineer the surface-modified implanted materials preventing the biomaterial-centered infection (BCI)

  4. Surface modification and properties of Bombyx mori silk fibroin films by antimicrobial peptide

    Energy Technology Data Exchange (ETDEWEB)

    Bai Liqiang [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China); Zhu Liangjun; Min Sijia [College of Animal Sciences, Zhejiang University, Hangzhou 310029 (China); Liu Lin; Cai Yurong [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China); Yao Juming [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China)], E-mail: yaoj@zstu.edu.cn

    2008-03-15

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH{sub 2})-NGIVKAGPAIAVLGEAAL-CONH{sub 2}, using the carbodiimide chemistry method. In order to avoid the dissolution of films during the modification procedure, the SFFs were first treated with 60% (v/v) ethanol aqueous solution, resulting a structural transition from unstable silk I to silk II. The investigation of modification conditions showed that the surface-modified SFFs had the satisfied antimicrobial activity and durability when they were activated by EDC.HCl/NHS solution followed by a treatment in CB peptide/PBS buffer (pH 6.5 or 8) solution at ambient temperature for 2 h. Moreover, the surface-modified SFFs showed the smaller contact angle due to the hydrophilic antimicrobial peptides coupled on the film surface, which is essential for the cell adhesion and proliferation. AFM results indicated that the surface roughness of SFFs was considerably increased after the modification by the peptides. The elemental composition analysis results also suggested that the peptides were tightly coupled to the surface of SFFs. This approach may provide a new option to engineer the surface-modified implanted materials preventing the biomaterial-centered infection (BCI)

  5. Biosynthesis and characterization of a non-repetitive polypeptide derived from silk fibroin heavy chain

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Gaoqiang; Wu, Mingyang; Yi, Honggen; Wang, Jiannan, E-mail: wangjn@suda.edu.cn

    2016-02-01

    Silk fibroin heavy chain is the major protein component of Bombyx mori silk fibroin and is composed of 12 repetitive and 11 non-repetitive regions, with the non-repetitive domain consisting of a hydrophilic polypeptide chain. In order to determine the biomedical function of the non-repetitive domain or potentially use it to modify hydrophobic biomaterials, high-purity isolation is necessary. Previously, we cloned and extended a gene motif (f(1)) encoding the non-repetitive domain. Here, this motif and its multimers are inserted into a glutathione S-transferase (GST)-tagged fusion-protein expression vector. Motif f(1) and multimers f(4) and f(8) were expressed in Escherichia coli BL21 cells following isopropyl β-D-1-thiogalactopyranoside induction, purified by GST-affinity chromatography, and single bands of purified fusion proteins GST-F(1), GST-F(4), and GST-F(8), were visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Target polypeptides F(1), F(4), and F(8), were cleaved clearly from the GST-fusion tag following thrombin digestion. Mass spectrometry results indicate that the molecular weights associated with fusion proteins GST-F(1), GST-F(4), and GST-F(8) are 31.5, 43.8, and 59.0 kDa, respectively, and with the cleaved polypeptides F(1), F(4), and F(8) are 4.8, 16.8, and 32.8 kDa, respectively. The F(1), F(4), and F(8) polypeptide chains are negatively charged with isoelectric points (pI) of 3.3, 3.2, and 3.0, respectively. The molecular weight and pI values of the polypeptide chains are consistent with the predicted values and the amino acid compositions similar to predicted sequences. FTIR and CD results show the molecular conformation of F(1) was mainly random coil, and more stable α-helix structure formed in longer molecular chain. - Highlights: • A non-repetitive domain and its multimers of silk fibroin were expressed by E. coli. • The corresponding target polypeptides F(1), F(4) and F(8) were cleaved clearly. • Their

  6. Characterization of Silk Fibroin Modified Surface: A Proteomic View of Cellular Response Proteins Induced by Biomaterials

    Directory of Open Access Journals (Sweden)

    Ming-Hui Yang

    2014-01-01

    Full Text Available The purpose of this study was to develop the pathway of silk fibroin (SF biopolymer surface induced cell membrane protein activation. Fibroblasts were used as an experimental model to evaluate the responses of cellular proteins induced by biopolymer material using a mass spectrometry-based profiling system. The surface was covered by multiwalled carbon nanotubes (CNTs and SF to increase the surface area, enhance the adhesion of biopolymer, and promote the rate of cell proliferation. The amount of adhered fibroblasts on CNTs/SF electrodes of quartz crystal microbalance (QCM greatly exceeded those on other surfaces. Moreover, analyzing differential protein expressions of adhered fibroblasts on the biopolymer surface by proteomic approaches indicated that CD44 may be a key protein. Through this study, utilization of mass spectrometry-based proteomics in evaluation of cell adhesion on biopolymer was proposed.

  7. Preferential Alignment of Hydroxyapatite Crystallites in Nanocomposites with Chemically Disintegrated Silk Fibroin

    International Nuclear Information System (INIS)

    Nemoto, Rei; Wang Li; Ikoma, Toshiyuki; Tanaka, Junzo; Senna, Mamoru

    2004-01-01

    Hydroxyapatite (HAp) nanocrystals were prepared at room temperature by a coprecipitation method from Ca(OH) 2 and H 3 PO 4 , in the presence of chemically disintegrated silk fibroin (SF). Adsorbed amounts of cations on SF and crystallinity of HAp in the composite were increased by the chemical disintegration of SF higher order structure. Preferential alignment of c-axis of HAp crystallites along the longitudinal direction of ca. 150nm SF fibril was observed. These changes due to disintegration of SF were discussed in terms of the chemical interaction between HAp and SF. The resulted composite with preferential alignment of HAp nanocrystals is a good candidate as a starting material for bone substitutes

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

    Science.gov (United States)

    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.

  9. * Fabrication and Characterization of Biphasic Silk Fibroin Scaffolds for Tendon/Ligament-to-Bone Tissue Engineering.

    Science.gov (United States)

    Font Tellado, Sònia; Bonani, Walter; Balmayor, Elizabeth R; Foehr, Peter; Motta, Antonella; Migliaresi, Claudio; van Griensven, Martijn

    2017-08-01

    Tissue engineering is an attractive strategy for tendon/ligament-to-bone interface repair. The structure and extracellular matrix composition of the interface are complex and allow for a gradual mechanical stress transfer between tendons/ligaments and bone. Thus, scaffolds mimicking the structural features of the native interface may be able to better support functional tissue regeneration. In this study, we fabricated biphasic silk fibroin scaffolds designed to mimic the gradient in collagen molecule alignment present at the interface. The scaffolds had two different pore alignments: anisotropic at the tendon/ligament side and isotropic at the bone side. Total porosity ranged from 50% to 80% and the majority of pores (80-90%) were ligament, enthesis, and cartilage markers significantly changed depending on pore alignment in each region of the scaffolds. In conclusion, the biphasic scaffolds fabricated in this study show promising features for tendon/ligament-to-bone tissue engineering.

  10. Preparation of wound dressing of polyvinyl alcohol/silk fibroin hydrogels by gamma radiation

    International Nuclear Information System (INIS)

    Kewsuwan, Prartana; Pongpat, Suchada; Sonsuk, Manit; Pongpat, Suchada

    2004-10-01

    Poly vinylalcohol/silk fibroin (PVA/SF) hydrogels were prepared by γ-radiation. The preparation conditions such as absorbed doses and PVA/SF concentrations were investigated. When exposed to γ -radiation, PVA/SF was crosslinked to yield high water absorption materials with water content of 100 - 1000% of their dried weight depending on the preparation conditions. The crosslinked density seems to be the main factor governing the swelling of these gels. The swelling behaviors in NaCl aqueous solutions were also investigated. The swelling of PVA/SF hydrogels decreases when exposed to electrolyte solution. With an increase of absorbed dose, the gel fraction of PVA/SF increases

  11. Densifying carbon nanotubes on assembly surface by the self-contraction of silk fibroin

    Science.gov (United States)

    Jiang, Chunyang; Yang, Xueqin; Zhao, Jingna; Li, Qingsong; Zhang, Ke-Qin; Zhang, Xiaohua; Li, Qingwen

    2018-04-01

    High densification of carbon nanotubes (CNTs) is important for high utilization efficiency of their superior properties in macroscopic assemblies. However, the conventional "top-down" compressing strategies have met problems to modify CNT assemblies at and below the micrometer scale. Here we report a molecular way to strap CNTs together via the self-contraction of silk fibroin (SF) during its drying process, resulting in a localized densification below the micrometer scale. Importantly, after the thermal removal of SF molecules, the densified assembly was well maintained. The SF-induced densification increased the average strength from 355 MPa to 960 MPa for CNT fibers, and from 1.45 GPa to 1.82 GPa for CNT ribbons, which contain much more CNTs on the surface.

  12. Microstructural, thermal and antibacterial properties of electron beam irradiated Bombyx mori silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Asha, S.; Sanjeev, Ganesh, E-mail: ganeshsanjeev@rediffmail.com [Microtron Center, Department of Studies in Physics, Mangalore University, Mangalagangotri - 574199 (India); Sangappa [Department of Studies in Physics, Mangalore University, Mangalagangotri - 574199 (India); Naik, Prashantha; Chandra, K. Sharat [Department of Biosciences, Mangalore University, Mangalagangotri - 574199 (India)

    2014-04-24

    The Bombyx mori silk fibroin (SF) films were prepared by solution casting method and the effects of electron beam on structural, thermal and antibacterial responses of the prepared films were studied. The electron irradiation for different doses was carried out using 8 MeV Microtron facility at Mangalore University. The changes in microstructural parameters and thermal stability of the films were investigated using Wide Angle X-ray Scattering (WAXS) and thermogravimetric analysis (TGA) respectively. Both microstructuralline parameters (crystallite size and lattice strain (g in %)) and thermal stability of the irradiated films have increased with radiation dosage. Agar diffusion method demonstrated the antibacterial activity of SF film which was increased after irradiation on both Gram-positive and Gram-negative species.

  13. A Novel Nanocomposite Particle of Hydroxyapatite and Silk Fibroin: Biomimetic Synthesis and Its Biocompatibility

    Directory of Open Access Journals (Sweden)

    Lin Niu

    2010-01-01

    Full Text Available A novel bone-like biomaterial of hydroxyapatite (HAP and silk fibroin (SF composite was developed by biomimetic synthesis. The composite was precipitated from drops of Ca(OH2 suspension and H3PO4 solution with SF. With this method, the HAP nanocrystals were obtained by self-assembling on a SF surface whose c-axis was aligned with the long-axis direction of SF in microstructures; this shares the same misconstrues of collagen and HAP with that in the natural bone. The HAP/SF composite then demonstrated that it could promote osteoblast proliferation in vitro and new bone formation in vivo. The novel biomaterial is a promising material for bone replacement and regeneration.

  14. Fast Setting Silk Fibroin Bioink for Bioprinting of Patient-Specific Memory-Shape Implants.

    Science.gov (United States)

    Costa, João B; Silva-Correia, Joana; Oliveira, Joaquim M; Reis, Rui L

    2017-11-01

    The pursuit for the "perfect" biomimetic and personalized implant for musculoskeletal tissue regeneration remains a big challenge. 3D printing technology that makes use of a novel and promising biomaterials can be part of the solution. In this study, a fast setting enzymatic-crosslinked silk fibroin (SF) bioink for 3D bioprinting is developed. Their properties are fine-tuned and different structures with good resolution, reproducibility, and reliability can be fabricated. Many potential applications exist for the SF bioinks including 3D bioprinted scaffolds and patient-specific implants exhibiting unique characteristics such as good mechanical properties, memory-shape feature, suitable degradation, and tunable pore architecture and morphology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Preparation of Antheraea pernyi Silk Fibroin Microparticles through a Facile Electrospinning Method

    Directory of Open Access Journals (Sweden)

    Xiufang Li

    2016-01-01

    Full Text Available The goal of this study was to fabricate Antheraea pernyi silk fibroin (ASF microparticles using electrospinning under mild processing conditions. To improve processability of the ASF solution, poly(ethylene oxide (PEO was used to regulate viscosity of ASF solution for electrospinning. It was found that the blend of ASF with PEO could form a bead-on-string structure with well spherical particles. Furthermore, aqueous ethanol and ultrasonic treatments could disrupt the nanofibrillar string structure between particles and ultimately produced water-insoluble ASF particles with submicron scale. Cell viability studies indicated that the ASF microparticles were nontoxic to EA926 cells. Moreover, fluorescent images based on FITC labeling showed that the ASF microparticles were easily uptaken by the cells. Aqueous-based electrospinning provides a potentially useful option for the fabrication of ASF microparticles based on this unique fibrous protein.

  16. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels

    Science.gov (United States)

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-04-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets.Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. Electronic supplementary information (ESI) available: XPS spectrum of the SF-GO hybrid film, SEM images of lyophilized GO dispersion and the failure surface of GO film. See DOI: 10.1039/c3nr00196b

  17. Orientational structure formation of silk fibroin with anisotropic properties in solutions; Orientastionnoe strukturoobrazovanie fibroina shelka s anizotropnymi svojstvami v rastvorakh

    Energy Technology Data Exchange (ETDEWEB)

    Kholmuminov, A A [AS RU, Institute of Polymer Chemistry and Physics, Tashkent (Uzbekistan)

    2008-06-15

    Key words:silk fibroin, dissolution, solution's model systems, gelation, orientational crystallization, optical polarization, longitudinal stream, {alpha} - {beta} transition, structure formation, phase transformations, relaxation, anisotropy of swelling and desorption, thermo- and biodegradation. Subjects of the inquiry: silk fibroin is the main subject of investigation. Fibroin's solutions were obtained on the base of water and organic solvents, containing salts. Comparative investigations were carried out by using biosolution - secretion of silkworm, solutions of silk sericin, cotton cellulose, methylcellulose, polystyrene and (co) polycrylonitrile. Aim of the inquiry: the elucidation of the regularities of silk fibroin anisotropic structures formation in the direct generation of orientational ordering in solutions taking into account of influences of its the molecular structures, configuration information, {alpha} - {beta} conformational transformations, and development jointly using polarization-optical and hydrodynamic methods to control of structure formation. And also definition of possibility fields for use biopolymers anisotropic structure formation principles. Method of inquiry: birefringence, dispersion optical rotation, circular dichroism, polarization- ultramicroscope, ultracentrifuge, viscosimetry, potentiometry, differential thermal analysis, chromatography, x-ray analysis, spectroscopy. The results achieved and their novelty: the physical regularity amorphous-crystalline fibroin dissolutions in salt-containing solvents based on chains melting, distribution and redistribution were recognized; fibroin statistical parameters, molecular-mass and conformational characteristics were established; It was shown that fibroin molecules turned into fully uncoiled and oriented state with the breakdown decay of {alpha}-spiral chain sections by I type phase transition mechanism, but in oriented state with {alpha}-spiral conservation by II type transition; the

  18. Modification of Silk Fibroin Using Diazonium Coupling Chemistry and the Effects on hMSC Proliferation and Differentiation

    Science.gov (United States)

    Murphy, Amanda R.; John, Peter St.; Kaplan, David L.

    2009-01-01

    A simple chemical modification method using diazonium coupling chemistry was developed to tailor the structure and hydrophilicity of silk fibroin protein. The extent of modification using several aniline derivatives was characterized using UV/vis and 1H NMR spectroscopy, and the resulting protein structure was analyzed with ATR-FTIR spectroscopy. Introduction of hydrophobic functional groups facilitated rapid conversion of the protein from a random coil to a β-sheet structure, while addition of hydrophilic groups inhibited this process. hMSCs were grown on these modified silks to assess the biocompatibility of these materials. The hydrophilicity of the silk derivatives was found to affect the growth rate and morphology, but hMSCs were able to attach, proliferate and differentiate into an osteogenic lineage on all of the silk derivatives. PMID:18417206

  19. Biomimetic Hybridization of Kevlar into Silk Fibroin: Nanofibrous Strategy for Improved Mechanic Properties of Flexible Composites and Filtration Membranes.

    Science.gov (United States)

    Lv, Lili; Han, Xiangsheng; Zong, Lu; Li, Mingjie; You, Jun; Wu, Xiaochen; Li, Chaoxu

    2017-08-22

    Silk, one of the strongest natural biopolymers, was hybridized with Kevlar, one of the strongest synthetic polymers, through a biomimetic nanofibrous strategy. Regenerated silk materials have outstanding properties in transparency, biocompatibility, biodegradability and sustainability, and promising applications as diverse as in pharmaceutics, electronics, photonic devices and membranes. To compete with super mechanic properties of their natural counterpart, regenerated silk materials have been hybridized with inorganic fillers such as graphene and carbon nanotubes, but frequently lose essential mechanic flexibility. Inspired by the nanofibrous strategy of natural biomaterials (e.g., silk fibers, hemp and byssal threads of mussels) for fantastic mechanic properties, Kevlar was integrated in regenerated silk materials by combining nanometric fibrillation with proper hydrothermal treatments. The resultant hybrid films showed an ultimate stress and Young's modulus two times as high as those of pure regenerated SF films. This is not only because of the reinforcing effect of Kevlar nanofibrils, but also because of the increasing content of silk β-sheets. When introducing Kevlar nanofibrils into the membranes of silk nanofibrils assembled by regenerated silk fibroin, the improved mechanic properties further enabled potential applications as pressure-driven nanofiltration membranes and flexible substrates of electronic devices.

  20. Biosynthesis of insulin-silk fibroin nanoparticles conjugates and in vitro evaluation of a drug delivery system

    Science.gov (United States)

    Yan, Hai-Bo; Zhang, Yu-Qing; Ma, Yong-Lei; Zhou, Li-Xia

    2009-11-01

    Silk fibroin derived from Bombyx mori is a biomacromolecular protein with outstanding biocompatibility. When it was dissolved in highly concentrated CaCl2 solution and then the mixture of the protein and salt was subjected to desalting treatments for long time in flowing water, the resulting liquid silk was water-soluble polypeptides with different molecular masses, ranging from 8 to 70 kDa. When the liquid silk was introduced rapidly into acetone, silk protein nanoparticles with a range of 40-120 nm in diameter could be obtained. The crystalline silk nanoparticles could be conjugated covalently with insulin alone with cross-linking reagent glutaraldehyde. In vitro properties of the insulin-silk fibroin nanoparticles (Ins-SFN) bioconjugates were determined by Enzyme-Linked Immunosorbent Assay (ELISA). The optimal conditions for the biosynthesis of Ins-SFN bioconjugates were investigated. The Ins-SFN constructs obtained by 8 h of covalent cross-linking with 0.7% cross-linking reagent and the proportion of insulin and SFN being 30 IU: 15 mg showed much higher recoveries (90-115%). When insulin was coupled covalently with silk nanoparticles, the resistance of the modified insulin to trypsin digestion and in vitro stability in human serum were greatly enhanced as compared with insulin alone. The results in human serum indicated that the half-life in vitro of the biosynthesized Ins-SFN derivatives was about 2.5 times more than that of native insulin. Therefore, the silk protein nanoparticles have the potential values for being studied and developed as a new bioconjugate for enzyme/polypeptide drug delivery system.

  1. Study of the effects of different sterilization methods on the properties of dense and porous silk fibroin membranes

    International Nuclear Information System (INIS)

    Weska, Raquel F.; Moraes, Mariana A. de; Beppu, Marisa M.

    2009-01-01

    Silk fibroin has been widely explored for many biomedical applications, due to its biocompatibility and biodegradability. Sterilization is a fundamental step in biomaterials processing, and it must not alter in a negative way the functionality of medical devices. The aim of this study was to analyze the influence of different sterilization methods in the physical and chemical characteristics of dense silk fibroin membranes. Dense fibroin membranes were sterilized by ultraviolet radiation, 70% ethanol, autoclave, ethylene oxide and gamma radiation, and were analyzed by SEM, FTIR-ATR and XRD. The results for sterilization indicated that the methods didn't cause degradation of the membranes, but the methods that used organic solvent, or increase of humidity and/or temperature (70% ethanol, autoclave and ethylene oxide) altered the molecular conformation of fibroin, increasing the proportion of β-sheet structure, what indicates an increase of crystallinity. This effect may be positive when a slower degradation of the membranes is desired, depending on the application as a bio material. (author)

  2. Phase Behaviour and Miscibility Studies of Collagen/Silk Fibroin Macromolecular System in Dilute Solutions and Solid State.

    Science.gov (United States)

    Ghaeli, Ima; de Moraes, Mariana A; Beppu, Marisa M; Lewandowska, Katarzyna; Sionkowska, Alina; Ferreira-da-Silva, Frederico; Ferraz, Maria P; Monteiro, Fernando J

    2017-08-18

    Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing collagen and RSF blends that can be used in pharmaceutical, drug delivery, and biomedical applications. Moreover, the conformational change of silk fibroin from random coil to beta sheet, in solution and in the final solid films, was detected by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. Scanning electron microscopy (SEM) exhibited alterations of surface morphology for the biocomposite films with different ratios. Surface contact angle measurement illustrated different hydrophobic properties for the blended film surfaces. Differential scanning calorimetry (DSC) showed that the formation of the beta sheet structure of silk fibroin enhances the thermal stability of the final blend films. Therefore, the novel method presented in this study resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.

  3. Robust microcapsules with controlled permeability from silk fibroin reinforced with graphene oxide.

    Science.gov (United States)

    Ye, Chunhong; Combs, Zachary A; Calabrese, Rossella; Dai, Hongqi; Kaplan, David L; Tsukruk, Vladimir V

    2014-12-29

    Robust and stable microcapsules are assembled from poly-amino acid-modified silk fibroin reinforced with graphene oxide flakes using layer-by-layer (LbL) assembly, based on biocompatible natural protein and carbon nanosheets. The composite microcapsules are extremely stable in acidic (pH 2.0) and basic (pH 11.5) conditions, accompanied with pH-triggered permeability, which facilitates the controllable encapsulation and release of macromolecules. Furthermore, the graphene oxide incorporated into ultrathin LbL shells induces greatly reinforced mechanical properties, with an elastic modulus which is two orders of magnitude higher than the typical values of original silk LbL shells and shows a significant, three-fold reduction in pore size. Such strong nanocomposite microcapsules can provide solid protection of encapsulated cargo under harsh conditions, indicating a promising candidate with controllable loading/unloading for drug delivery, reinforcement, and bioengineering applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

    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.

  5. 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.

  6. Enhanced osteogenesis of β-tricalcium phosphate reinforced silk fibroin scaffold for bone tissue biofabrication.

    Science.gov (United States)

    Lee, Dae Hoon; Tripathy, Nirmalya; Shin, Jae Hun; Song, Jeong Eun; Cha, Jae Geun; Min, Kyung Dan; Park, Chan Hum; Khang, Gilson

    2017-02-01

    Scaffolds, used for tissue regeneration are important to preserve their function and morphology during tissue healing. Especially, scaffolds for bone tissue engineering should have high mechanical properties to endure load of bone. Silk fibroin (SF) from Bombyx mori silk cocoon has potency as a type of biomaterials in the tissue engineering. β-tricalcium phosphate (β-TCP) as a type of bioceramics is also critical as biomaterials for bone regeneration because of its biocompatibility, osteoconductivity, and mechanical strength. The aim of this study was to fabricate three-dimensional SF/β-TCP scaffolds and access its availability for bone grafts through in vitro and in vivo test. The scaffolds were fabricated in each different ratios of SF and β-TCP (100:0, 75:25, 50:50, 25:75). The characterizations of scaffolds were conducted by FT-IR, compressive strength, porosity, and SEM. The in vitro and in vivo tests were carried out by MTT, ALP, RT-PCR, SEM, μ-CT, and histological staining. We found that the SF/β-TCP scaffolds have high mechanical strength and appropriate porosity for bone tissue engineering. The study showed that SF/β-TCP (75:25) scaffold exhibited the highest osteogenesis compared with other scaffolds. The results suggested that SF/β-TCP (75:25) scaffold can be applied as one of potential bone grafts for bone tissue engineering. Copyright © 2016. Published by Elsevier B.V.

  7. Human dental pulp stem cells and gingival fibroblasts seeded into silk fibroin scaffolds have the same ability in attracting vessels

    Directory of Open Access Journals (Sweden)

    Anna eWoloszyk

    2016-04-01

    Full Text Available Neovascularization is one of the most important processes during tissue repair and regeneration. Current healing approaches based on the use of biomaterials combined with stem cells in critical-size bone defects fail due to the insufficient implant vascularization and integration into the host tissues. Therefore, here we studied the attraction, ingrowth, and distribution of blood vessels from the chicken embryo chorioallantoic membrane into implanted silk fibroin scaffolds seeded with either human dental pulp stem cells or human gingival fibroblasts. Perfusion capacity was evaluated by non-invasive in vivo Magnetic Resonance Imaging while the number and density of blood vessels were measured by histomorphometry. Our results demonstrate that human dental pulp stem cells and gingival fibroblasts possess equal abilities in attracting vessels within silk fibroin scaffolds. Additionally, the prolonged in vitro pre-incubation period of these two cell populations favors the homogeneous distribution of vessels within silk fibroin scaffolds, which further improves implant survival and guarantees successful healing and regeneration.

  8. Attachment and growth of human bone marrow derived mesenchymal stem cells on regenerated antheraea pernyi silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Luan Xiying [Institute of Medical Biotechnology, Jiangsu Province Key Laboratory of Stem Cell, Suzhou University, Suzhou 215007 (China); Wang Yong [Institute of Medical Biotechnology, Jiangsu Province Key Laboratory of Stem Cell, Suzhou University, Suzhou 215007 (China); Duan Xiang [Institute of Medical Biotechnology, Jiangsu Province Key Laboratory of Stem Cell, Suzhou University, Suzhou 215007 (China); Duan Qiaoyan [Institute of Medical Biotechnology, Jiangsu Province Key Laboratory of Stem Cell, Suzhou University, Suzhou 215007 (China); Li Mingzhong [School of Materials Engineering, Suzhou University, Suzhou 215006 (China); Lu Shenzhou [School of Materials Engineering, Suzhou University, Suzhou 215006 (China); Zhang Huanxiang [Institute of Medical Biotechnology, Jiangsu Province Key Laboratory of Stem Cell, Suzhou University, Suzhou 215007 (China); Zhang Xueguang [Institute of Medical Biotechnology, Jiangsu Province Key Laboratory of Stem Cell, Suzhou University, Suzhou 215007 (China)

    2006-12-15

    Silk fibroin of the silkworm Bombyx mori has been studied extensively, while the research on Antheraea pernyi silk fibroin (A. pernyi SF) in biomaterials is only at an early stage. In this study, the attachment, morphology, growth and phenotype of human bone marrow derived mesenchymal stem cells (hBMSCs) cultured on the regenerated A. pernyi SF films were studied in vitro. The results indicated that the attachment of hBMSCs on the regenerated A. pernyi SF films was almost the same as that on the collagen films. MTT and cell counting analyses demonstrated that the growth of hBMSCs on the regenerated A. pernyi SF films was better than that on controls. Moreover, electron scanning microscopy and fluorescence-activated cell sorting assays showed that the regenerated A. pernyi SF supported hBMSCs growth and functional maintenance compared with the controls. These data suggest that the regenerated A. pernyi SF, like Bombyx mori silk fibroin (B. mori SF) and collagen, can support hBMSCs attachment, growth and phenotypic maintenance, and has better biocompatibilities for hBMSCs in vitro culture.

  9. Attachment and growth of human bone marrow derived mesenchymal stem cells on regenerated antheraea pernyi silk fibroin films

    International Nuclear Information System (INIS)

    Luan Xiying; Wang Yong; Duan Xiang; Duan Qiaoyan; Li Mingzhong; Lu Shenzhou; Zhang Huanxiang; Zhang Xueguang

    2006-01-01

    Silk fibroin of the silkworm Bombyx mori has been studied extensively, while the research on Antheraea pernyi silk fibroin (A. pernyi SF) in biomaterials is only at an early stage. In this study, the attachment, morphology, growth and phenotype of human bone marrow derived mesenchymal stem cells (hBMSCs) cultured on the regenerated A. pernyi SF films were studied in vitro. The results indicated that the attachment of hBMSCs on the regenerated A. pernyi SF films was almost the same as that on the collagen films. MTT and cell counting analyses demonstrated that the growth of hBMSCs on the regenerated A. pernyi SF films was better than that on controls. Moreover, electron scanning microscopy and fluorescence-activated cell sorting assays showed that the regenerated A. pernyi SF supported hBMSCs growth and functional maintenance compared with the controls. These data suggest that the regenerated A. pernyi SF, like Bombyx mori silk fibroin (B. mori SF) and collagen, can support hBMSCs attachment, growth and phenotypic maintenance, and has better biocompatibilities for hBMSCs in vitro culture

  10. 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

  11. 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

  12. 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

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

    Science.gov (United States)

    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.

  14. Structure and interaction of silk fibroin and graphene oxide in concentrated solution under shear.

    Science.gov (United States)

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

    2018-02-01

    Considering the high biocompatibility of regenerated silk fibroin (RSF) and the good enhancement effect of graphene oxide (GO), various RSF/GO composite materials have been previously investigated, and found that GO plays a vital role in the fabrication of high-performance RSF/GO materials. However, its effects on the structure of RSF solution are unclear. Therefore, in this work, we studied the rheological and optical properties, as well as the aggregation behavior of concentrated RSF/GO solution in response to applied shear. The results demonstrated that the presence of GO sheets in RSF solution increased the shear resistance, while delayed the sol-gel transition. Moreover, GO sheets were not favorable to the formation of the ordered structures of RSF. The results from small angle X-ray scattering (SAXS) of RSF/GO solution also showed that the shear process promoted the formation of RSF/GO interface. The data also provided insights into the structural evolution within the mixture solutions, which can be beneficial to the future design and fabrication of nanofiller-reinforced high-performance materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. A graded graphene oxide-hydroxyapatite/silk fibroin biomimetic scaffold for bone tissue engineering.

    Science.gov (United States)

    Wang, Qian; Chu, Yanyan; He, Jianxin; Shao, Weili; Zhou, Yuman; Qi, Kun; Wang, Lidan; Cui, Shizhong

    2017-11-01

    To better mimic natural bone, a graphene oxide-hydroxyapatite/silk fibroin (cGO-HA/SF) scaffold was fabricated by biomineralizing carboxylated GO sheets, blending with SF, and freeze-drying. The material has increasing porosity and decreasing density from outside to inside. Analysis of GO mineralization in simulated body fluid indicated that carboxylation and Chitosan may synergistically regulate HA growth along the c-axis of weakly crystalline, rod-like GO-HA particles. Compared with HA/SF gradient composites, a cGO-HA gradient scaffold with cGO:HA mass ratio 1:4 has 5-fold and 2.5-fold higher compressive strength and compressive modulus, respectively. Additionally, the cGO-HA/SF composite stimulated mouse mesenchymal stem cell adhesion and proliferation, alkaline phosphatase secretion, and mineral deposition more strongly than HA/SF and pure HA scaffolds. Hence, the material may prove to be an excellent and versatile scaffold for bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. 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.

  17. Vitamin E-loaded silk fibroin nanofibrous mats fabricated by green process for skin care application.

    Science.gov (United States)

    Sheng, Xiaoyue; Fan, Linpeng; He, Chuanglong; Zhang, Kuihua; Mo, Xiumei; Wang, Hongsheng

    2013-05-01

    In the present study, we reported fabrication and skin benefit of a novel vitamin E (VE)-loaded silk fibroin (SF) nanofibrous mats. RRR-α-Tocopherol polyethylene glycol 1000 succinate (VE TPGS), a water-soluble derivative of VE, was incorporated into SF nanofiber successfully by aqua solution electrospinning for the first time. Morphology of the composite nanofibers changed with the different amount of VE TPGS: a ribbon-like shape for lower loading dose of VE TPGS, while a round shape for higher loading dose (more than 4% (wt/wt) based on the weight of SF). After treated with 75% (v/v) ethanol vapor, the composite nanofibrous mats showed an excellent water-resistant ability. In vitro study disclosed a sustained release behavior of VE TPGS disassociated from the nanofibrous mats. The mouse skin fibroblasts (L929 cells) cultured on the VE-loaded SF nanofibrous mats spread and proliferated much better than on cover slips. Moreover, the incorporation of VE TPGS was found strengthening the ability of SF nanofibrous mats on protecting the cells against oxidation stress induced by tert-butyl hydroperoxide. Our data presented impressive skin benefits of this VE-loaded SF nanofibrous mats, suggesting a promising applicative potential of this novel product on personal skin care, tissue regeneration and other related area. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Cartilage Tissue Engineering with Silk Fibroin Scaffolds Fabricated by Indirect Additive Manufacturing Technology.

    Science.gov (United States)

    Chen, Chih-Hao; Liu, Jolene Mei-Jun; Chua, Chee-Kai; Chou, Siaw-Meng; Shyu, Victor Bong-Hang; Chen, Jyh-Ping

    2014-03-13

    Advanced tissue engineering (TE) technology based on additive manufacturing (AM) can fabricate scaffolds with a three-dimensional (3D) environment suitable for cartilage regeneration. Specifically, AM technology may allow the incorporation of complex architectural features. The present study involves the fabrication of 3D TE scaffolds by an indirect AM approach using silk fibroin (SF). From scanning electron microscopic observations, the presence of micro-pores and interconnected channels within the scaffold could be verified, resulting in a TE scaffold with both micro- and macro-structural features. The intrinsic properties, such as the chemical structure and thermal characteristics of SF, were preserved after the indirect AM manufacturing process. In vitro cell culture within the SF scaffold using porcine articular chondrocytes showed a steady increase in cell numbers up to Day 14. The specific production (per cell basis) of the cartilage-specific extracellular matrix component (collagen Type II) was enhanced with culture time up to 12 weeks, indicating the re-differentiation of chondrocytes within the scaffold. Subcutaneous implantation of the scaffold-chondrocyte constructs in nude mice also confirmed the formation of ectopic cartilage by histological examination and immunostaining.

  19. Biocompatibility and osteoconduction of macroporous silk fibroin implants in cortical defects in sheep.

    Science.gov (United States)

    Uebersax, Lorenz; Apfel, Tanja; Nuss, Katja M R; Vogt, Rainer; Kim, Hyoen Yoo; Meinel, Lorenz; Kaplan, David L; Auer, Joerg A; Merkle, Hans P; von Rechenberg, Brigitte

    2013-09-01

    The goal of the presented study was to compare the biocompatibility and cellular responses to porous silk fibroin (SF) scaffolds produced in a water-based (UPW) or a solvent based process (HFIP) using two different SF sources. For that reason, four different SF scaffolds were implanted (n=6) into drill hole defects in the cancellous bone of the sheep tibia and humerus. The scaffolds were evaluated histologically for biocompatibility, cell-material interaction, and cellular ingrowth. New bone formation was observed macroscopically and histologically at 8 weeks after implantation. For semiquantitative evaluation, the investigated parameters were scored and statistically analyzed (factorial ANOVA). All implants showed good biocompatibility as evident by low infiltration of inflammatory cells and the absent encapsulation of the scaffolds in connective tissue. Multinuclear foreign body giant cells (MFGCs) and macrophages were present in all parts of the scaffold at the material surface and actively degrading the SF material. Cell ingrowth and vascularization were uniform across the scaffold. However, in HFIP scaffolds, local regions of void pores were present throughout the scaffold, probably due to the low pore interconnectivity in this scaffold type in contrast to UPW scaffolds. The amount of newly formed bone was very low in both scaffold types but was more abundant in the periphery than in the center of the scaffolds and for HFIP scaffolds mainly restricted to single pores. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. 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)

  1. Flexible organic light emitting diodes fabricated on biocompatible silk fibroin substrate

    Science.gov (United States)

    Liu, Yuqiang; Xie, Yuemin; Liu, Yuan; Song, Tao; Zhang, Ke-Qin; Liao, Liangsheng; Sun, Baoquan

    2015-10-01

    Flexible and biodegradable electronics are currently under extensive investigation for biocompatible and environmentally-friendly applications. Synthetic plastic foils are widely used as substrates for flexible electronics. But typical plastic substrates such as polyethylene naphthalate (PEN) could not be degraded in a natural bio-environment. A great demand still exists for a next-generation biocompatible and biodegradable substrate for future application. For example, electronic devices can be potentially integrated into the human body. In this work, we demonstrate that the biocompatible and biodegradable natural silk fibroin (SF) films embedded with silver nanowires (AgNWs) mesh could be employed as conductive transparent substrates to fabricate flexible organic light emitting diodes (OLEDs). Compared with commercial PEN substrates coated with indium tin oxide, the AgNWs/SF composite substrates exhibit a similar sheet resistance of 12 Ω sq-1, a lower surface roughness, as well as a broader light transmission range. Flexible OLEDs based on AgNWs/SF substrates achieve a current efficiency of 19 cd A-1, demonstrating the potential of the flexible AgNWs/SF films as conductive and transparent substrates for next-generation biodegradable devices.

  2. Flexible organic light emitting diodes fabricated on biocompatible silk fibroin substrate

    International Nuclear Information System (INIS)

    Liu, Yuqiang; Xie, Yuemin; Liu, Yuan; Song, Tao; Liao, Liangsheng; Sun, Baoquan; Zhang, Ke-Qin

    2015-01-01

    Flexible and biodegradable electronics are currently under extensive investigation for biocompatible and environmentally-friendly applications. Synthetic plastic foils are widely used as substrates for flexible electronics. But typical plastic substrates such as polyethylene naphthalate (PEN) could not be degraded in a natural bio-environment. A great demand still exists for a next-generation biocompatible and biodegradable substrate for future application. For example, electronic devices can be potentially integrated into the human body. In this work, we demonstrate that the biocompatible and biodegradable natural silk fibroin (SF) films embedded with silver nanowires (AgNWs) mesh could be employed as conductive transparent substrates to fabricate flexible organic light emitting diodes (OLEDs). Compared with commercial PEN substrates coated with indium tin oxide, the AgNWs/SF composite substrates exhibit a similar sheet resistance of 12 Ω sq −1 , a lower surface roughness, as well as a broader light transmission range. Flexible OLEDs based on AgNWs/SF substrates achieve a current efficiency of 19 cd A −1 , demonstrating the potential of the flexible AgNWs/SF films as conductive and transparent substrates for next-generation biodegradable devices. (paper)

  3. 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)

  4. 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.

  5. Cartilage Tissue Engineering with Silk Fibroin Scaffolds Fabricated by Indirect Additive Manufacturing Technology

    Directory of Open Access Journals (Sweden)

    Chih-Hao Chen

    2014-03-01

    Full Text Available Advanced tissue engineering (TE technology based on additive manufacturing (AM can fabricate scaffolds with a three-dimensional (3D environment suitable for cartilage regeneration. Specifically, AM technology may allow the incorporation of complex architectural features. The present study involves the fabrication of 3D TE scaffolds by an indirect AM approach using silk fibroin (SF. From scanning electron microscopic observations, the presence of micro-pores and interconnected channels within the scaffold could be verified, resulting in a TE scaffold with both micro- and macro-structural features. The intrinsic properties, such as the chemical structure and thermal characteristics of SF, were preserved after the indirect AM manufacturing process. In vitro cell culture within the SF scaffold using porcine articular chondrocytes showed a steady increase in cell numbers up to Day 14. The specific production (per cell basis of the cartilage-specific extracellular matrix component (collagen Type II was enhanced with culture time up to 12 weeks, indicating the re-differentiation of chondrocytes within the scaffold. Subcutaneous implantation of the scaffold-chondrocyte constructs in nude mice also confirmed the formation of ectopic cartilage by histological examination and immunostaining.

  6. Electrohydrodynamic bubbling: an alternative route to fabricate porous structures of silk fibroin based materials.

    Science.gov (United States)

    Ekemen, Zeynep; Ahmad, Zeeshan; Stride, Eleanor; Kaplan, David; Edirisinghe, Mohan

    2013-05-13

    Conventional fabrication techniques and structures employed in the design of silk fibroin (SF) based porous materials provide only limited control over pore size and require several processing stages. In this study, it is shown that, by utilizing electrohydrodynamic bubbling, not only can new hollow spherical structures of SF be formed in a single step by means of bubbles, but the resulting bubbles can serve as pore generators when dehydrated. The bubble characteristics can be controlled through simple adjustments to the processing parameters. Bubbles with diameters in the range of 240-1000 μm were fabricated in controlled fashion. FT-IR characterization confirmed that the rate of air infused during processing enhanced β-sheet packing in SF at higher flow rates. Dynamic mechanical analysis also demonstrated a correlation between air flow rate and film tensile strength. Results indicate that electrohydrodynamically generated SF and their composite bubbles can be employed as new tools to generate porous structures in a controlled manner with a range of potential applications in biocoatings and tissue engineering scaffolds.

  7. Structural characteristics and properties of the regenerated silk fibroin prepared from formic acid.

    Science.gov (United States)

    Um, I C; Kweon, H Y; Park, Y H; Hudson, S

    2001-08-20

    Structural characteristics and thermal and solution properties of the regenerated silk fibroin (SF) prepared from formic acid (FU) were compared with those of SF from water (AU). According to the turbidity and shear viscosity measurement, SF formic acid solution was stable and transparent, no molecular aggregations occurred. The sample FU exhibited the beta-sheet structure, while AU random coil conformation using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry. The effects of methanol treatment on samples were also examined. According to the measurement of crystallinity (XRD) and crystallinity index (FTIR), the concept of long/short-range ordered structure formation was proposed. Long-range ordered crystallites are predominantly formed for methanol treated SF film while SF film cast from formic acid favors the formation of short-range ordered structure. The relaxation temperatures of SF films measured by dynamic thermomechanical analysis supported the above mechanism due to the sensitivity of relaxation temperature on the short-range order.

  8. Microporous silk fibroin scaffolds embedding PLGA microparticles for controlled growth factor delivery in tissue engineering.

    Science.gov (United States)

    Wenk, Esther; Meinel, Anne J; Wildy, Sarah; Merkle, Hans P; Meinel, Lorenz

    2009-05-01

    The development of prototype scaffolds for either direct implantation or tissue engineering purposes and featuring spatiotemporal control of growth factor release is highly desirable. Silk fibroin (SF) scaffolds with interconnective pores, carrying embedded microparticles that were loaded with insulin-like growth factor I (IGF-I), were prepared by a porogen leaching protocol. Treatments with methanol or water vapor induced water insolubility of SF based on an increase in beta-sheet content as analyzed by FTIR. Pore interconnectivity was demonstrated by SEM. Porosities were in the range of 70-90%, depending on the treatment applied, and were better preserved when methanol or water vapor treatments were prior to porogen leaching. IGF-I was encapsulated into two different types of poly(lactide-co-glycolide) microparticles (PLGA MP) using uncapped PLGA (50:50) with molecular weights of either 14 or 35 kDa to control IGF-I release kinetics from the SF scaffold. Embedded PLGA MP were located in the walls or intersections of the SF scaffold. Embedment of the PLGA MP into the scaffolds led to more sustained release rates as compared to the free PLGA MP, whereas the hydrolytic degradation of the two PLGA MP types was not affected. The PLGA types used had distinct effects on IGF-I release kinetics. Particularly the supernatants of the lower molecular weight PLGA formulations turned out to release bioactive IGF-I. Our studies justify future investigations of the developed constructs for tissue engineering applications.

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

    Science.gov (United States)

    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

  10. Precisely printable and biocompatible silk fibroin bioink for digital light processing 3D printing.

    Science.gov (United States)

    Kim, Soon Hee; Yeon, Yeung Kyu; Lee, Jung Min; Chao, Janet Ren; Lee, Young Jin; Seo, Ye Been; Sultan, Md Tipu; Lee, Ok Joo; Lee, Ji Seung; Yoon, Sung-Il; Hong, In-Sun; Khang, Gilson; Lee, Sang Jin; Yoo, James J; Park, Chan Hum

    2018-04-24

    Although three-dimensional (3D) bioprinting technology has gained much attention in the field of tissue engineering, there are still several significant engineering challenges to overcome, including lack of bioink with biocompatibility and printability. Here, we show a bioink created from silk fibroin (SF) for digital light processing (DLP) 3D bioprinting in tissue engineering applications. The SF-based bioink (Sil-MA) was produced by a methacrylation process using glycidyl methacrylate (GMA) during the fabrication of SF solution. The mechanical and rheological properties of Sil-MA hydrogel proved to be outstanding in experimental testing and can be modulated by varying the Sil-MA contents. This Sil-MA bioink allowed us to build highly complex organ structures, including the heart, vessel, brain, trachea and ear with excellent structural stability and reliable biocompatibility. Sil-MA bioink is well-suited for use in DLP printing process and could be applied to tissue and organ engineering depending on the specific biological requirements.

  11. Characterization of Silk Fibroin/Chitosan 3D Porous Scaffold and In Vitro Cytology.

    Directory of Open Access Journals (Sweden)

    Shuguang Zeng

    Full Text Available Bone tissue engineering is a powerful tool to treat bone defects caused by trauma, infection, tumors and other factors. Both silk fibroin (SF and chitosan (CS are non-toxic and have good biocompatibility, but are poor biological scaffolds when used alone. In this study, the microscopic structure and related properties of SF/CS composite scaffolds with different component ratios were examined. The scaffold material most suitable for osteoblast growth was determined, and these results offer an experimental basis for the future reconstruction of bone defects. First, via freeze-drying and chemical crosslinking methods, SF/CS composites with different component ratios were prepared and their structure was characterized. Changes in the internal structure of the SF and CS mixture were observed, confirming that the mutual modification between the two components was complete and stable. The internal structure of the composite material was porous and three-dimensional with a porosity above 90%. We next studied the pore size, swelling ratio, water absorption ratio, degradation and in vitro cell proliferation. For the 40% SF-60% CS group, the pore size of the scaffold was suitable for the growth of osteoblasts, and the rate of degradation was steady. This favors the early adhesion, growth and proliferation of MG-63 cells. In addition to good biocompatibility and satisfactory cell affinity, this material promotes the secretion of extracellular matrix materials by osteoblasts. Thus, 40% SF-60% CS is a good material for bone tissue engineering.

  12. Characterization of Silk Fibroin/Chitosan 3D Porous Scaffold and In Vitro Cytology.

    Science.gov (United States)

    Zeng, Shuguang; Liu, Lei; Shi, Yong; Qiu, Junqi; Fang, Wei; Rong, Mingdeng; Guo, Zehong; Gao, Wenfeng

    2015-01-01

    Bone tissue engineering is a powerful tool to treat bone defects caused by trauma, infection, tumors and other factors. Both silk fibroin (SF) and chitosan (CS) are non-toxic and have good biocompatibility, but are poor biological scaffolds when used alone. In this study, the microscopic structure and related properties of SF/CS composite scaffolds with different component ratios were examined. The scaffold material most suitable for osteoblast growth was determined, and these results offer an experimental basis for the future reconstruction of bone defects. First, via freeze-drying and chemical crosslinking methods, SF/CS composites with different component ratios were prepared and their structure was characterized. Changes in the internal structure of the SF and CS mixture were observed, confirming that the mutual modification between the two components was complete and stable. The internal structure of the composite material was porous and three-dimensional with a porosity above 90%. We next studied the pore size, swelling ratio, water absorption ratio, degradation and in vitro cell proliferation. For the 40% SF-60% CS group, the pore size of the scaffold was suitable for the growth of osteoblasts, and the rate of degradation was steady. This favors the early adhesion, growth and proliferation of MG-63 cells. In addition to good biocompatibility and satisfactory cell affinity, this material promotes the secretion of extracellular matrix materials by osteoblasts. Thus, 40% SF-60% CS is a good material for bone tissue engineering.

  13. 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

  14. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Cao

    Full Text Available Strongly alkaline electrolyzed water (SAEW was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+ concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  15. Building Interfaces: Mechanisms, fabrication, and applications at the biotic/abiotic interface for silk fibroin based bioelectronic and biooptical devices

    Science.gov (United States)

    Brenckle, Mark

    Recent efforts in bioelectronics and biooptics have led to a shift in the materials and form factors used to make medical devices, including high performance, implantable, and wearable sensors. In this context, biopolymer-based devices must be processed to interface the soft, curvilinear biological world with the rigid, inorganic world of traditional electronics and optics. This poses new material-specific fabrication challenges in designing such devices, which in turn requires further understanding of the fundamental physical behaviors of the materials in question. As a biopolymer, silk fibroin protein has remarkable promise in this space, due to its bioresorbability, mechanical strength, optical clarity, ability to be reshaped on the micro- and nano-scale, and ability to stabilize labile compounds. Application of this material to devices at the biotic/abiotic interface will require the development of fabrication techniques for nano-patterning, lithography, multilayer adhesion, and transfer printing in silk materials. In this work, we address this need through fundamental study of the thermal and diffusional properties of silk protein as it relates to these fabrication strategies. We then leverage these properties to fabricate devices well suited to the biotic/abiotic interface in three areas: shelf-ready sensing, implantable transient electronics, and wearable biosensing. These example devices will illustrate the advantages of silk in this class of bioelectronic and biooptical devices, from fundamentals through application, and contribute to a silk platform for the development of future devices that combine biology with high technology.

  16. Structural evolution of regenerated silk fibroin under shear: Combined wide- and small-angle x-ray scattering experiments using synchrotron radiation

    International Nuclear Information System (INIS)

    Rossle, Manfred; Panine, Pierre; Urban, Volker S.; Riekel, Christine

    2004-01-01

    The structural evolution of regenerated Bombyx mori silk fibroin during shearing with a Couette cell has been studied in situ by synchrotron radiation small- and wide-angle x-ray scattering techniques. An elongation of fibroin molecules was observed with increasing shear rate, followed by an aggregation phase. The aggregates were found to be amorphous with β-conformation according to infrared spectroscopy. Scanning x-ray microdiffraction with a 5 (micro)m beam on aggregated material, which had solidified in air, showed silk II reflections and a material with equatorial reflections close to the silk I structure reflections, but with strong differences in reflection intensities. This silk I type material shows up to two low-angle peaks suggesting the presence of water molecules that might be intercalated between hydrogen-bonded sheets.

  17. Structural evolution of regenerated silk fibroin under shear: Combined wide- and small-angle x-ray scattering experiments using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rossle, Manfred [European Molecular Biology Laboratory (EMBL), France; Panine, Pierre [European Synchrotron Radiation Facility (ESRF); Urban, Volker S [ORNL; Riekel, Christine [European Synchrotron Radiation Facility (ESRF)

    2004-04-01

    The structural evolution of regenerated Bombyx mori silk fibroin during shearing with a Couette cell has been studied in situ by synchrotron radiation small- and wide-angle x-ray scattering techniques. An elongation of fibroin molecules was observed with increasing shear rate, followed by an aggregation phase. The aggregates were found to be amorphous with {beta}-conformation according to infrared spectroscopy. Scanning x-ray microdiffraction with a 5 {micro}m beam on aggregated material, which had solidified in air, showed silk II reflections and a material with equatorial reflections close to the silk I structure reflections, but with strong differences in reflection intensities. This silk I type material shows up to two low-angle peaks suggesting the presence of water molecules that might be intercalated between hydrogen-bonded sheets.

  18. Steel fiber reinforced concrete

    International Nuclear Information System (INIS)

    Baloch, S.U.

    2005-01-01

    Steel-Fiber Reinforced Concrete is constructed by adding short fibers of small cross-sectional size .to the fresh concrete. These fibers reinforce the concrete in all directions, as they are randomly oriented. The improved mechanical properties of concrete include ductility, impact-resistance, compressive, tensile and flexural strength and abrasion-resistance. These uniqlte properties of the fiber- reinforcement can be exploited to great advantage in concrete structural members containing both conventional bar-reinforcement and steel fibers. The improvements in mechanical properties of cementitious materials resulting from steel-fiber reinforcement depend on the type, geometry, volume fraction and material-properties of fibers, the matrix mix proportions and the fiber-matrix interfacial bond characteristics. Effects of steel fibers on the mechanical properties of concrete have been investigated in this paper through a comprehensive testing-programme, by varying the fiber volume fraction and the aspect-ratio (Lid) of fibers. Significant improvements are observed in compressive, tensile, flexural strength and impact-resistance of concrete, accompanied by marked improvement in ductility. optimum fiber-volume fraction and aspect-ratio of steel fibers is identified. Test results are analyzed in details and relevant conclusions drawn. The research is finally concluded with future research needs. (author)

  19. 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)

  20. Preparation and characterization of genipin-cross-linked silk fibroin/chitosan sustained-release microspheres

    Directory of Open Access Journals (Sweden)

    Zeng SG

    2015-05-01

    Full Text Available Shuguang Zeng,1,* Manwen Ye,1,2,* Junqi Qiu,1 Wei Fang,1 Mingdeng Rong,1 Zehong Guo,1 Wenfen Gao11Department of Oral and Maxillofacial Surgery, Guangdong Provincial Stomatological Hospital, Southern Medical University, 2Department of Stomatology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China*These authors contributed equally to this workAbstract: We report the effects of distinct concentrations of genipin and silk fibroin (SF:chitosan (CS ratios on the formation of SF–CS composite microspheres. We selected microspheres featuring an SF:CS ratio of 1:1, encapsulated various concentrations of bovine serum albumin (BSA, and then compared their encapsulation efficiency and sustained-release rate with those of pure CS microspheres. We determined that the following five groups of microspheres were highly spherical and featured particle sizes ranging from 70 µm to 147 µm: mass ratio of CS:SF =1:0.5, 0.1 g or 0.5 g genipin; CS:SF =1:1, 0.05 g or 1 g genipin; and CS:SF =1:2, 0.5 g genipin. The microspheres prepared using 1:1 CS:SF ratio and 0.05 g genipin in the presence of 10 mg, 20 mg, and 50 mg of BSA exhibited encapsulation efficiencies of 50.16%±4.32%, 56.58%±3.58%, and 42.19%±7.47%, respectively. Fourier-transform infrared spectroscopy (FTIR results showed that SF and CS were cross-linked and that the α-helices and random coils of SF were converted into β-sheets. BSA did not chemically react with CS or SF. Moreover, thermal gravimetric analysis (TGA results showed that the melting point of BSA did not change, which confirmed the FTIR results, and X-ray diffraction results showed that BSA was entrapped in microspheres in a noncrystalline form, which further verified the TGA and FTIR data. The sustained-release microspheres prepared in the presence of 10 mg, 20 mg, and 50 mg of BSA burst release 30.79%±3.43%, 34.41%±4.46%, and 41.75%±0.96% of the

  1. Three dimensional poly(ε-caprolactone) and silk fibroin nanocomposite fibrous matrix for artificial dermis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Min, E-mail: yiyi1124@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Chae, Taesik, E-mail: apsiky@gmail.com [Department of Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Sheikh, Faheem A., E-mail: faheem99in@yahoo.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Ju, Hyung Woo, E-mail: anabasjoo@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Moon, Bo Mi, E-mail: toribom@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Park, Hyun Jung, E-mail: hyunjungpark869@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Park, Ye Ri, E-mail: payeri89@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Park, Chan Hum, E-mail: hlpch@paran.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Hallym University, Chuncheon 200-704 (Korea, Republic of)

    2016-11-01

    Ideal dermal substitutes should have comparable physicochemical and biological properties to the natural skin tissue. In this study, we report a novel strategy to “engineer” controlled 3D nanocomposite fibrous matrix of poly(ε-caprolactone) (PCL) and silk fibroin (SF) for an artificial dermis application. Using a custom-designed cold-plate electrospinning and automatic magnet agitation system, up to 6 mm of the thickness was achieved resulting from the accumulation of ice crystal layers on the PCL nanofibers surface-modified with the SF particles. The sacrificed ice crystals induced interconnected macro-pores ranging from tens to hundreds μm. The agitation system introduced uniform distribution of the SF protein within/on the nanofibers, preventing the particles from precipitation and agglomeration. NIH 3T3 fibroblasts proliferated in vitro on the PCL and PCL/SF scaffolds for 7 days, but there was no statistical difference between the groups. Conversely, In vivo rat model studies revealed that the wound healing rate and collagen deposition increased with the SF content within the nanocomposites. The unique 3D construct with the PCL/SF nanocomposite fibers provided desirable spatial cues, surface topography, and surface chemistry for the native cells to infiltrate into the scaffolds. The wound healing potential of the nanocomposites was comparable to the commercial Matriderm® artificial dermis. - Highlights: • 3D macro-porous tissue engineering scaffold constructed with PCL nanofibers and SF nanoparticles. • Fabrication of the PCL/SF nanocomposite fibrous scaffold via a custom-designed cold plate electrospinning (CPE) and automatic magnet agitation (AMA) system. • Comparable wound healing capacity of the PCL/SF scaffolds to the commercial Matriderm® artificial dermis.

  2. 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.

  3. Silk fibroin enhances peripheral nerve regeneration by improving vascularization within nerve conduits.

    Science.gov (United States)

    Wang, Chunyang; Jia, Yachao; Yang, Weichao; Zhang, Cheng; Zhang, Kuihua; Chai, Yimin

    2018-07-01

    Silk fibroin (SF)-based nerve conduits have been widely used to bridge peripheral nerve defects. Our previous study showed that nerve regeneration in a SF-blended poly (l-lactide-co-ɛ-caprolactone) [P(LLA-CL)] nerve conduit is better than that in a P(LLA-CL) conduit. However, the involved mechanisms remain unclarified. Because angiogenesis within a nerve conduit plays an important role in nerve regeneration, vascularization of SF/P(LLA-CL) and P(LLA-CL) conduits was compared both in vitro and in vivo. In the present study, we observed that SF/P(LLA-CL) nanofibers significantly promoted fibroblast proliferation, and vascular endothelial growth factor secreted by fibroblasts seeded in SF/P(LLA-CL) nanofibers was more than seven-fold higher than that in P(LLA-CL) nanofibers. Conditioned medium of fibroblasts in the SF/P(LLA-CL) group stimulated more human umbilical vein endothelial cells (HUVEC) to form capillary-like networks and promoted faster HUVEC migration. The two kinds of nerve conduits were used to bridge 10-mm-length nerve defects in rats. At 3 weeks of reparation, the blood vessel area in the SF/P(LLA-CL) group was significantly larger than that in the P(LLA-CL) group. More regenerated axons and Schwann cells were also observed in the SF/P(LLA-CL) group, which was consistent with the results of blood vessels. Collectively, our data revealed that the SF/P(LLA-CL) nerve conduit enhances peripheral nerve regeneration by improving angiogenesis within the conduit. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2070-2077, 2018. © 2018 Wiley Periodicals, Inc.

  4. Immobilization of acetylcholinesterase via biocompatible interface of silk fibroin for detection of organophosphate and carbamate pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Xue Rui [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Kang Tianfang, E-mail: kangtf@yahoo.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Lu Liping; Cheng Shuiyuan [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

    2012-06-01

    An amperometric biosensor for the detection of organophosphate and carbamate pesticides was developed based on the immobilization of acetylcholinesterase (AChE) on regenerated silk fibroin (SF) matrix by non-covalent adsorption. SF and AChE were coated sequentially on the surface of the glassy carbon electrode (GCE) which was modified with multiwall carbon nanotube (MWNTs). The obtained biosensor was denoted as AChE-SF/MWNTs/GCE. The atomic force microscopy images showed that the SF matrix provided a more homogeneous interface for the AChE immobilization. The aggregation of immobilizing AChE was therefore avoided. The cyclic voltammogram of thiocholine at this biosensor exhibited a well defined oxidation peak at 0.667 V (vs. SCE). The inhibition rate of methyl parathion to the immobilized AChE was proportional to the logarithm of the concentration of methyl parathion over the range of the concentration of methyl parathion from 3.5 Multiplication-Sign 10{sup -6} to 2.0 Multiplication-Sign 10{sup -3} M with a detection limit of 5.0 Multiplication-Sign 10{sup -7} M. Similarly, the linearly response range of carbaryl was from 1.0 Multiplication-Sign 10{sup -7} to 3.0 Multiplication-Sign 10{sup -5} M with a detection limit of 6.0 Multiplication-Sign 10{sup -8} M. The experimental results indicate that AChE not only can be immobilized steadily on the SF matrix, but also the bioactivity of immobilizing AChE can be preserved effectively.

  5. Fabrication and characterization of silk fibroin/bioactive glass composite films

    International Nuclear Information System (INIS)

    Zhu Hailin; Liu Na; Feng Xinxing; Chen Jianyong

    2012-01-01

    Composite films of silk fibroin (SF) with nano bioactive glass (NBG) were prepared by the solvent casting method, and the structures and properties of the composite films were characterized. Fourier transform infrared (FT-IR) spectroscopy analysis shows that the random coil and β-sheet structure co-exist in the SF films. Results of field emission scanning electron microscope (FESEM) indicate that the NBG particles are uniformly dispersed in the SF films. The measurements of the water contact angles suggest that the incorporation of NBG into SF can improve the hydrophilicity of the composites. The bioactivity of the composite films was evaluated by soaking in 1.5 times simulated body fluid (1.5 × SBF), and formation of a hydroxycarbonate apatite (HCA) layer was determined by XRD and FESEM. The results show that the SF/NBG composite film is bioactive as it induces the formation of HCA on the surface of the composite film after soaking in 1.5 × SBF for 7 days. In vitro osteoblasts attachment and proliferation tests show that the composite film is a good matrix for the growth of osteoblasts. Consequently, the incorporation of NBG into the SF film can enhance both the bioactivity and biocompatibility of the film, which suggests that the SF/NBG composite film may be a potential biomaterial for bone tissue engineering. - Highlights: ► The incorporation of NBG into SF can improve the hydrophilicity of the SF/NBG composite films. ► The SF/NBG composite films show the better bioactivity than the pure SF film. ► The SF/NBG composite films facilitate cell growth and promote cell proliferation and differentiation.

  6. Biofunctional Ionic-Doped Calcium Phosphates: Silk Fibroin Composites for Bone Tissue Engineering Scaffolding.

    Science.gov (United States)

    Pina, S; Canadas, R F; Jiménez, G; Perán, M; Marchal, J A; Reis, R L; Oliveira, J M

    2017-01-01

    The treatment and regeneration of bone defects caused by traumatism or diseases have not been completely addressed by current therapies. Lately, advanced tools and technologies have been successfully developed for bone tissue regeneration. Functional scaffolding materials such as biopolymers and bioresorbable fillers have gained particular attention, owing to their ability to promote cell adhesion, proliferation, and extracellular matrix production, which promote new bone growth. Here, we present novel biofunctional scaffolds for bone regeneration composed of silk fibroin (SF) and β-tricalcium phosphate (β-TCP) and incorporating Sr, Zn, and Mn, which were successfully developed using salt-leaching followed by a freeze-drying technique. The scaffolds presented a suitable pore size, porosity, and high interconnectivity, adequate for promoting cell attachment and proliferation. The degradation behavior and compressive mechanical strengths showed that SF/ionic-doped TCP scaffolds exhibit improved characteristics for bone tissue engineering when compared with SF scaffolds alone. The in vitro bioactivity assays using a simulated body fluid showed the growth of an apatite layer. Furthermore, in vitro assays using human adipose-derived stem cells presented different effects on cell proliferation/differentiation when varying the doping agents in the biofunctional scaffolds. The incorporation of Zn into the scaffolds led to improved proliferation, while the Sr- and Mn-doped scaffolds presented higher osteogenic potential as demonstrated by DNA quantification and alkaline phosphatase activity. The combination of Sr with Zn led to an influence on cell proliferation and osteogenesis when compared with single ions. Our results indicate that biofunctional ionic-doped composite scaffolds are good candidates for further in vivo studies on bone tissue regeneration. © 2017 S. Karger AG, Basel.

  7. Three dimensional poly(ε-caprolactone) and silk fibroin nanocomposite fibrous matrix for artificial dermis

    International Nuclear Information System (INIS)

    Lee, Jung Min; Chae, Taesik; Sheikh, Faheem A.; Ju, Hyung Woo; Moon, Bo Mi; Park, Hyun Jung; Park, Ye Ri; Park, Chan Hum

    2016-01-01

    Ideal dermal substitutes should have comparable physicochemical and biological properties to the natural skin tissue. In this study, we report a novel strategy to “engineer” controlled 3D nanocomposite fibrous matrix of poly(ε-caprolactone) (PCL) and silk fibroin (SF) for an artificial dermis application. Using a custom-designed cold-plate electrospinning and automatic magnet agitation system, up to 6 mm of the thickness was achieved resulting from the accumulation of ice crystal layers on the PCL nanofibers surface-modified with the SF particles. The sacrificed ice crystals induced interconnected macro-pores ranging from tens to hundreds μm. The agitation system introduced uniform distribution of the SF protein within/on the nanofibers, preventing the particles from precipitation and agglomeration. NIH 3T3 fibroblasts proliferated in vitro on the PCL and PCL/SF scaffolds for 7 days, but there was no statistical difference between the groups. Conversely, In vivo rat model studies revealed that the wound healing rate and collagen deposition increased with the SF content within the nanocomposites. The unique 3D construct with the PCL/SF nanocomposite fibers provided desirable spatial cues, surface topography, and surface chemistry for the native cells to infiltrate into the scaffolds. The wound healing potential of the nanocomposites was comparable to the commercial Matriderm® artificial dermis. - Highlights: • 3D macro-porous tissue engineering scaffold constructed with PCL nanofibers and SF nanoparticles. • Fabrication of the PCL/SF nanocomposite fibrous scaffold via a custom-designed cold plate electrospinning (CPE) and automatic magnet agitation (AMA) system. • Comparable wound healing capacity of the PCL/SF scaffolds to the commercial Matriderm® artificial dermis.

  8. Self-assembly fabrication of microencapsulated n-octadecane with natural silk fibroin shell for thermal-regulating textiles

    International Nuclear Information System (INIS)

    Zhao, Liang; Luo, Jie; Wang, Hao; Song, Guolin; Tang, Guoyi

    2016-01-01

    Highlights: • Microencapsulated n-octadecane with silk fibroin shell was fabricated. • The microcapsules show high heat storage capability. • The microcapsules are good candidate for thermal-regulating textiles. - Graphical Abstract: Display Omitted - Abstract: Novel microencapsulated n-octadecane with natural silk fibroin (SF) shell was prepared using a self-assembly method in oil-in-water (o/w) emulsion. The microstructures and chemical compositions of the resultant microcapsules were investigated by scanning electronic microscope (SEM) and Fourier transformation infrared spectroscope (FT-IR). SEM images demonstrated that the microcapsules presented spherical shape with a median size of 4–5 µm. FT-IR results confirmed that SF shell was successfully fabricated upon n-octadecane core. According to the DSC and TGA examinations, the resultant microcapsules exhibited good phase-change performance, high thermal-storage capability and high thermal reliability. The microencapsulated n-octadecane with SF shell synthesized in the present study would be a potential candidate for the application of thermal-regulating textiles or fibers and biological medical materials, etc.

  9. Fabrication and characterization of drug-loaded nano-hydroxyapatite/polyamide 66 scaffolds modified with carbon nanotubes and silk fibroin

    Directory of Open Access Journals (Sweden)

    Yao MZ

    2016-11-01

    Full Text Available Meng-Zhu Yao,1 Ming-Yi Huang-Fu,1 Hui-Na Liu,1 Xia-Rong Wang,1 Xiaoxia Sheng,2 Jian-Qing Gao1 1Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, 2Hangzhou SoliPharma Co., Ltd, Hangzhou, Zhejiang, People’s Republic of China Abstract: Nano-hydroxyapatite/polyamide 66 (nHA/PA66 porous scaffolds were fabricated by a phase inversion method. Carbon nanotubes (CNTs and silk fibroin (SF were used to modify the surface of the nHA/PA66 scaffolds by freeze-drying and cross-linking. Dexamethasone was absorbed to the CNTs to promote the osteogenic differentiation of bone mesenchymal stem cells (BMSCs. The cell viability of BMSCs was investigated by changing the concentration of the CNT dispersion, and the most biocompatible scaffold was selected. In addition, the morphology and mechanical property of the scaffolds were investigated. The results showed that the nHA/PA66 scaffolds modified with CNTs and SF met the requirements of bone tissue engineering scaffolds. The dexamethasone-loaded CNT/SF-nHA/PA66 composite scaffold promoted the osteogenic differentiation of BMSCs, and the drug-loaded scaffolds are expected to function as effective bone tissue engineering scaffolds. Keywords: BMSCs, tissue engineering, porous scaffold, carbon nanotubes, silk fibroin, surface modification, dexamethasone

  10. 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

  11. Construction of engineering adipose-like tissue in vivo utilizing human insulin gene-modified umbilical cord mesenchymal stromal cells with silk fibroin 3D scaffolds.

    Science.gov (United States)

    Li, Shi-Long; Liu, Yi; Hui, Ling

    2015-12-01

    We evaluated the use of a combination of human insulin gene-modified umbilical cord mesenchymal stromal cells (hUMSCs) with silk fibroin 3D scaffolds for adipose tissue engineering. In this study hUMSCs were isolated and cultured. HUMSCs infected with Ade-insulin-EGFP were seeded in fibroin 3D scaffolds with uniform 50-60 µm pore size. Silk fibroin scaffolds with untransfected hUMSCs were used as control. They were cultured for 4 days in adipogenic medium and transplanted under the dorsal skins of female Wistar rats after the hUMSCs had been labelled with chloromethylbenzamido-1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (CM-Dil). Macroscopical impression, fluorescence observation, histology and SEM were used for assessment after transplantation at 8 and 12 weeks. Macroscopically, newly formed adipose tissue was observed in the experimental group and control group after 8 and 12 weeks. Fluorescence observation supported that the formed adipose tissue originated from seeded hUMSCs rather than from possible infiltrating perivascular tissue. Oil red O staining of newly formed tissue showed that there was substantially more tissue regeneration in the experimental group than in the control group. SEM showed that experimental group cells had more fat-like cells, whose volume was larger than that of the control group, and degradation of the silk fibroin scaffold was greater under SEM observation. This study provides significant evidence that hUMSCs transfected by adenovirus vector have good compatibility with silk fibroin scaffold, and adenoviral transfection of the human insulin gene can be used for the construction of tissue-engineered adipose. Copyright © 2013 John Wiley & Sons, Ltd.

  12. Influence of Philosamia ricini silk fibroin components on morphology, secondary structure and thermal properties of chitosan biopolymer film.

    Science.gov (United States)

    Prasong, S; Nuanchai, K; Wilaiwan, S

    2009-09-15

    This study aimed to prepare Eri (Philosamia ricini) Silk Fibroin (SF)/chitosan (CS) blend films by a solvent evaporation method and to compare the blend films with both native SF and CS films. Influence of SF ratios on the morphology, secondary structure and thermal decomposition of the CS blend films were investigated. The native SF and CS films were uniform and homogeneous without phase separation. For the blend films, the uniform can be found less than 60% of SF composition. All of SF/CS blend films showed both SF and CS characteristics. FT-IR results showed that the blend films composed of both random coil and beta-sheet with predominant of beta-sheet form. Interaction of intermolecular between SF and CS have occurred which were measured by thermogravimetric thermograms. Increasing of SF contents was leading to the increase of beta-sheet structures which were enhanced the thermal stability of the CS blend films.

  13. A Review of Structure Construction of Silk Fibroin Biomaterials from Single Structures to Multi-Level Structures

    Directory of Open Access Journals (Sweden)

    Yu Qi

    2017-03-01

    Full Text Available The biological performance of artificial biomaterials is closely related to their structure characteristics. Cell adhesion, migration, proliferation, and differentiation are all strongly affected by the different scale structures of biomaterials. Silk fibroin (SF, extracted mainly from silkworms, has become a popular biomaterial due to its excellent biocompatibility, exceptional mechanical properties, tunable degradation, ease of processing, and sufficient supply. As a material with excellent processability, SF can be processed into various forms with different structures, including particulate, fiber, film, and three-dimensional (3D porous scaffolds. This review discusses and summarizes the various constructions of SF-based materials, from single structures to multi-level structures, and their applications. In combination with single structures, new techniques for creating special multi-level structures of SF-based materials, such as micropatterning and 3D-printing, are also briefly addressed.

  14. Semi-interpenetrating polymer networks composed of silk fibroin and poly(ethylene glycol) for wound dressing

    International Nuclear Information System (INIS)

    Kweon, HaeYong; Yeo, Joo-hong; Lee, Kwang-gill; Lee, Hyun Chul; Na, Hee Sam; Won, Young Ho; Cho, Chong Su

    2008-01-01

    Semi-interpenetrating polymer networks (SIPNs) composed of silk fibroin (SF) and poly(ethylene glycol) (PEG) were prepared by photopolymerization of a PEG macromer in the presence of SF to improve the mechanical properties of SF sponge as wound dressing. The morphological structure of the SF/PEG SIPNs was observed to be composed of an interconnected microporous surface and a cross-sectional area. SF/PEG SIPNs showed non-cytotoxicity evaluated by a cell proliferation method using L929 fibroblasts. Wound contraction treated with SF/PEG SIPNs sponges was faster than that of Vaseline gauze as a control. Histological observation confirmed that the deposition of collagen in the dermis was organized by covering the wound area with SF/PEG SIPNs. The above results indicated that SF/PEG SIPNs could be used as wound dressing

  15. A macroporous heparin-releasing silk fibroin scaffold improves islet transplantation outcome by promoting islet revascularisation and survival.

    Science.gov (United States)

    Mao, Duo; Zhu, Meifeng; Zhang, Xiuyuan; Ma, Rong; Yang, Xiaoqing; Ke, Tingyu; Wang, Lianyong; Li, Zongjin; Kong, Deling; Li, Chen

    2017-09-01

    Islet transplantation is considered the most promising therapeutic option with the potential to cure diabetes. However, efficacy of current clinical islet transplantation is limited by long-term graft dysfunction and attrition. We have investigated the therapeutic potential of a silk fibroin macroporous (SF) scaffold for syngeneic islet transplantation in diabetic mice. The SF scaffold was prepared via lyophilisation, which enables incorporation of active compounds including cytokines, peptide and growth factors without compromising their biological activity. For the present study, a heparin-releasing SF scaffold (H-SF) in order to evaluate the versatility of the SF scaffold for biological functionalisation. Islets were then co-transplanted with H-SF or SF scaffolds in the epididymal fat pad of diabetic mice. Mice from both H-SF and SF groups achieved 100% euglycaemia, which was maintained for 1year. More importantly, the H-SF-islets co-transplantation led to more rapid reversal of hyperglycaemia, complete normalisation of glucose responsiveness and lower long-term blood glucose levels. This superior transplantation outcome is attributable to H-SF-facilitated islet revascularisation and cell proliferation since significant increase of islet endocrine and endothelial cells proliferation was shown in grafts retrieved from H-SF-islets co-transplanted mice. Better intra-islet vascular reformation was also evident, accompanied by VEGF upregulation. In addition, when H-SF was co-transplanted with islets extracted from vegfr2-luc transgenic mice in vivo, sustained elevation of bioluminescent signal that corresponds to vegfr2 expression was collected, implicating a role of heparin-dependent activation of endogenous VEGF/VEGFR2 pathway in promoting islet revascularisation and proliferation. In summary, the SF scaffolds provide an open platform as scaffold development for islet transplantation. Furthermore, given the pro-angiogenic, pro-survival and minimal post

  16. Design and Characterization of a Silk-Fibroin-Based Drug Delivery Platform Using Naproxen as a Model Drug

    Directory of Open Access Journals (Sweden)

    Tatyana Dyakonov

    2012-01-01

    Full Text Available The objective of this proof-of-concept study was to develop a platform for controlled drug delivery based on silk fibroin (SF and to explore the feasibility of using SF in oral drug delivery. The SF-containing matrixes were prepared via spray-drying and film casting, and the release profile of the model drug naproxen sodium was evaluated. Attenuated total reflectance Fourier transform infrared spectroscopy (FTIR has been used to observe conformational changes in SF- and drug-containing compositions. SF-based films, spray-dried microparticles, and matrixes loaded with naproxen were prepared. Both FTIR spectra and in vitro dissolution data demonstrated that SF β-sheet conformation regulates the release profile of naproxen. The controlled release characteristics of the SF-containing compositions were evaluated as a function of SF concentration, temperature, and exposure to dehydrating solvents. The results suggest that SF may be an attractive polymer for use in controlled drug delivery systems.

  17. 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.

  18. Composite biocompatible hydroxyapatite-silk fibroin coatings for medical implants obtained by Matrix Assisted Pulsed Laser Evaporation

    International Nuclear Information System (INIS)

    Miroiu, F.M.; Socol, G.; Visan, A.; Stefan, N.; Craciun, D.; Craciun, V.; Dorcioman, G.; Mihailescu, I.N.; Sima, L.E.; Petrescu, S.M.; Andronie, A.; Stamatin, I.; Moga, S.; Ducu, C.

    2010-01-01

    The aim of this study was to obtain biomimetic inorganic-organic thin films as coatings for metallic medical implants. These contain hydroxyapatite, the inorganic component of the bony tissues, and a natural biopolymer - silk fibroin - added in view to induce the surface functionalization. Hydroxyapatite (HA), silk fibroin (FIB) and composite HA-FIB films were obtained by Matrix Assisted Pulsed Laser Evaporation (MAPLE) in order to compare their physical and biological performances as coatings on metallic prostheses. We used an excimer laser source (KrF*, λ = 248 nm, τ = 25 ns) operated at 10 Hz repetition rate. Coatings were deposited on quartz, Si and Ti substrates and then subjected to physical (FTIR, XRD, AFM, SEM) analyses, correlated with the results of the cytocompatibility in vitro tests. The hybrid films were synthesized from frozen targets of aqueous suspensions with 3:2 or 3:4 weight ratio of HA:FIB. An appropriate stoichiometric and functional transfer was obtained for 0.4-0.5 J/cm 2 laser fluence. FTIR spectra of FIB and HA-FIB films exhibited distinctive absorption maxima, in specific positions of FIB random coil form: 1540 cm -1 amide II, 1654 cm -1 amide I, 1243 cm -1 amide III, while the peak from 1027 cm -1 appeared only for HA and composite films. Osteosarcoma SaOs2 cells cultured 72 h on FIB and HA-FIB films showed increased viability, good spreading and normal cell morphology. The well-elongated, flattened cells are a sign of an appropriate interaction with the MAPLE FIB and composite HA-FIB coatings.

  19. Composite biocompatible hydroxyapatite-silk fibroin coatings for medical implants obtained by Matrix Assisted Pulsed Laser Evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Miroiu, F.M., E-mail: marimona.miroiu@inflpr.ro [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Socol, G.; Visan, A.; Stefan, N.; Craciun, D.; Craciun, V.; Dorcioman, G.; Mihailescu, I.N. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Sima, L.E.; Petrescu, S.M. [Institute of Biochemistry, Romanian Academy, 296 Splaiul Independentei, 060031 Bucharest (Romania); Andronie, A.; Stamatin, I. [3Nano-SAE Alternative Energy Sources-University of Bucharest, Faculty of Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov (Romania); Moga, S.; Ducu, C. [University of Pitesti, Targul din Vale Str, no. 1, 110040 Pitesti (Romania)

    2010-05-25

    The aim of this study was to obtain biomimetic inorganic-organic thin films as coatings for metallic medical implants. These contain hydroxyapatite, the inorganic component of the bony tissues, and a natural biopolymer - silk fibroin - added in view to induce the surface functionalization. Hydroxyapatite (HA), silk fibroin (FIB) and composite HA-FIB films were obtained by Matrix Assisted Pulsed Laser Evaporation (MAPLE) in order to compare their physical and biological performances as coatings on metallic prostheses. We used an excimer laser source (KrF*, {lambda} = 248 nm, {tau} = 25 ns) operated at 10 Hz repetition rate. Coatings were deposited on quartz, Si and Ti substrates and then subjected to physical (FTIR, XRD, AFM, SEM) analyses, correlated with the results of the cytocompatibility in vitro tests. The hybrid films were synthesized from frozen targets of aqueous suspensions with 3:2 or 3:4 weight ratio of HA:FIB. An appropriate stoichiometric and functional transfer was obtained for 0.4-0.5 J/cm{sup 2} laser fluence. FTIR spectra of FIB and HA-FIB films exhibited distinctive absorption maxima, in specific positions of FIB random coil form: 1540 cm{sup -1} amide II, 1654 cm{sup -1} amide I, 1243 cm{sup -1} amide III, while the peak from 1027 cm{sup -1} appeared only for HA and composite films. Osteosarcoma SaOs2 cells cultured 72 h on FIB and HA-FIB films showed increased viability, good spreading and normal cell morphology. The well-elongated, flattened cells are a sign of an appropriate interaction with the MAPLE FIB and composite HA-FIB coatings.

  20. 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.

  1. Mimicked cartilage scaffolds of silk fibroin/hyaluronic acid with stem cells for osteoarthritis surgery: Morphological, mechanical, and physical clues

    International Nuclear Information System (INIS)

    Jaipaew, Jirayut; Wangkulangkul, Piyanun; Meesane, Jirut; Raungrut, Pritsana; Puttawibul, Puttisak

    2016-01-01

    Osteoarthritis is a critical disease that comes from degeneration of cartilage tissue. In severe cases surgery is generally required. Tissue engineering using scaffolds with stem cell transplantation is an attractive approach and a challenge for orthopedic surgery. For sample preparation, silk fibroin (SF)/hyaluronic acid (HA) scaffolds in different ratios of SF/HA (w/w) (i.e., 100:0, 90:10, 80:20, and 70:30) were formed by freeze-drying. The morphological, mechanical, and physical clues were considered in this research. The morphological structure of the scaffolds was observed by scanning electron microscope. The mechanical and physical properties of the scaffolds were analyzed by compressive and swelling ratio testing, respectively. For the cell experiments, scaffolds were seeded and cultured with human umbilical cord-derived mesenchymal stem cells (HUMSCs). The cultured scaffolds were tested for cell viability, histochemistry, immunohistochemistry, and gene expression. The SF with HA scaffolds showed regular porous structures. Those scaffolds had a soft and elastic characteristic with a high swelling ratio and water uptake. The SF/HA scaffolds showed a spheroid structure of the cells in the porous structure particularly in the SF80 and SF70 scaffolds. Cells could express Col2a, Agg, and Sox9 which are markers for chondrogenesis. It could be deduced that SF/HA scaffolds showed significant clues for suitability in cartilage tissue engineering and in surgery for osteoarthritis. - Highlights: • Silk fibroin/Hyaluronic acid was fabricated into mimicked scaffolds. • Mimicked scaffolds were incorporated with stem cells for chondrogenesis. • Mimicked scaffolds showed the clues for chondrogenic regulation. • Mimicked scaffolds had suitable performance for cartilage tissue engineering • Mimicked scaffolds showed promise for osteoarthritis surgery.

  2. Mimicked cartilage scaffolds of silk fibroin/hyaluronic acid with stem cells for osteoarthritis surgery: Morphological, mechanical, and physical clues

    Energy Technology Data Exchange (ETDEWEB)

    Jaipaew, Jirayut [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Wangkulangkul, Piyanun [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Department of Surgery, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Meesane, Jirut, E-mail: jirutmeesane999@yahoo.co.uk [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Raungrut, Pritsana [Department of Biomedical Science, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Puttawibul, Puttisak [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Department of Surgery, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand)

    2016-07-01

    Osteoarthritis is a critical disease that comes from degeneration of cartilage tissue. In severe cases surgery is generally required. Tissue engineering using scaffolds with stem cell transplantation is an attractive approach and a challenge for orthopedic surgery. For sample preparation, silk fibroin (SF)/hyaluronic acid (HA) scaffolds in different ratios of SF/HA (w/w) (i.e., 100:0, 90:10, 80:20, and 70:30) were formed by freeze-drying. The morphological, mechanical, and physical clues were considered in this research. The morphological structure of the scaffolds was observed by scanning electron microscope. The mechanical and physical properties of the scaffolds were analyzed by compressive and swelling ratio testing, respectively. For the cell experiments, scaffolds were seeded and cultured with human umbilical cord-derived mesenchymal stem cells (HUMSCs). The cultured scaffolds were tested for cell viability, histochemistry, immunohistochemistry, and gene expression. The SF with HA scaffolds showed regular porous structures. Those scaffolds had a soft and elastic characteristic with a high swelling ratio and water uptake. The SF/HA scaffolds showed a spheroid structure of the cells in the porous structure particularly in the SF80 and SF70 scaffolds. Cells could express Col2a, Agg, and Sox9 which are markers for chondrogenesis. It could be deduced that SF/HA scaffolds showed significant clues for suitability in cartilage tissue engineering and in surgery for osteoarthritis. - Highlights: • Silk fibroin/Hyaluronic acid was fabricated into mimicked scaffolds. • Mimicked scaffolds were incorporated with stem cells for chondrogenesis. • Mimicked scaffolds showed the clues for chondrogenic regulation. • Mimicked scaffolds had suitable performance for cartilage tissue engineering • Mimicked scaffolds showed promise for osteoarthritis surgery.

  3. 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.

  4. 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.

  5. Drug release from core-shell PVA/silk fibroin nanoparticles fabricated by one-step electrospraying.

    Science.gov (United States)

    Cao, Yang; Liu, Fengqiu; Chen, Yuli; Yu, Tao; Lou, Deshuai; Guo, Yuan; Li, Pan; Wang, Zhigang; Ran, Haitao

    2017-09-20

    Silk fibroin (SF), a FDA-approved natural protein, is renowned for its great biocompatibility, biodegradability, and mechanical properties. SF-based nanoparticles provide new options for drug delivery with their tunable drug loading and release properties. To take advantage of the features of carrier polymers, we present a one-step electrospraying method that combines SF, polyvinyl alcohol (PVA) and therapeutic drugs without an emulsion process. A distinct core-shell structure was obtained with the PVA core and silk shell after the system was properly set up. The model drug, doxorubicin, was encapsulated in the core with a greater than 90% drug encapsulation efficiency. Controllable drug release profiles were achieved by alternating the PVA/SF ratio. Although the initial burst release of the drug was minimized by the SF coating, a large number of drug molecules remained entrapped by the carrier polymers. To promote and trigger drug release on demand, low intensity focused ultrasound (US) was applied. The US was especially advantageous for accelerating the drug diffusion and release. The apoptotic activity of MDA-MB-231 cells incubated with drug-loaded nanoparticles was found to increase with time. In addition, we also observed PVA/SF nanoparticles that could elicit a drug release in response to pH.

  6. 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

  7. Surface modification of silk fibroin fibers with poly(methyl methacrylate) and poly(tributylsilyl methacrylate) via RAFT polymerization for marine antifouling applications

    Energy Technology Data Exchange (ETDEWEB)

    Buga, Mihaela-Ramona [National Research and Development Institute for Cryogenics and Isotopic Technologies, ICIT Rm. Valcea, 240050 Rm. Valcea, Uzinei 4, CP7, Raureni, Valcea (Romania); Zaharia, Cătălin, E-mail: zaharia.catalin@gmail.com [Advanced Polymer Materials Group, University Politehnica of Bucharest, 1-7, Gh. Polizu Street, Sector 1, 011061 Bucharest (Romania); Bălan, Mihai [National Research and Development Institute for Cryogenics and Isotopic Technologies, ICIT Rm. Valcea, 240050 Rm. Valcea, Uzinei 4, CP7, Raureni, Valcea (Romania); Bressy, Christine [Université de Toulon, MAPIEM, EA 4323, 83957 La Garde (France); Ziarelli, Fabio [Fédération des Sciences Chimiques de Marseille, CNRS-FR1739, Spectropole, 13397 Marseille (France); Margaillan, André [Université de Toulon, MAPIEM, EA 4323, 83957 La Garde (France)

    2015-06-01

    In this study, silk fibroin surface containing hydroxyl and aminogroups was firstly modified using a polymerizable coupling agent 3-(trimethoxysilyl) propyl methacrylate (MPS), in order to induce vinyl groups onto the fiber surface. The reversible addition–fragmentation chain transfer (RAFT)-mediated polymerization of methyl methacrylate (MMA) and tributylsilyl methacrylate (TBSiMA) through the immobilized vinyl bond on the silk fibroin surface in the presence of 2-cyanoprop-2-yl dithiobenzoate (CPDB) as chain-transfer agent and 2,2′-azobis(isobutyronitrile) (AIBN) as initiator was conducted in toluene solution at 70 °C for 24 h. The structure and properties of the modified fiber were characterized by Fourier Transform Infrared Spectroscopy, {sup 13}C, {sup 29}Si Nuclear Magnetic Resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), confirming the presence of the coupling molecule and the methacrylate groups onto the silk fibroin fiber surface. Molecular weight distributions were assessed by triple detection size exclusion chromatography (TD-SEC) in order to verify the livingness of the polymerization. - Highlights: • SF surface containing hydroxyl and amino groups was firstly modified with MPS. • RAFT polymerizations of MMA and TBSiMA were studied. • TD-SEC was used to verify the livingness of the RAFT polymerization. • The grafted polymer chains enhance the thermal stability of the SF fibers. • The grafted fibers could be potentially promising candidates as antifouling agents.

  8. Surface modification of silk fibroin fibers with poly(methyl methacrylate) and poly(tributylsilyl methacrylate) via RAFT polymerization for marine antifouling applications

    International Nuclear Information System (INIS)

    Buga, Mihaela-Ramona; Zaharia, Cătălin; Bălan, Mihai; Bressy, Christine; Ziarelli, Fabio; Margaillan, André

    2015-01-01

    In this study, silk fibroin surface containing hydroxyl and aminogroups was firstly modified using a polymerizable coupling agent 3-(trimethoxysilyl) propyl methacrylate (MPS), in order to induce vinyl groups onto the fiber surface. The reversible addition–fragmentation chain transfer (RAFT)-mediated polymerization of methyl methacrylate (MMA) and tributylsilyl methacrylate (TBSiMA) through the immobilized vinyl bond on the silk fibroin surface in the presence of 2-cyanoprop-2-yl dithiobenzoate (CPDB) as chain-transfer agent and 2,2′-azobis(isobutyronitrile) (AIBN) as initiator was conducted in toluene solution at 70 °C for 24 h. The structure and properties of the modified fiber were characterized by Fourier Transform Infrared Spectroscopy, 13 C, 29 Si Nuclear Magnetic Resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), confirming the presence of the coupling molecule and the methacrylate groups onto the silk fibroin fiber surface. Molecular weight distributions were assessed by triple detection size exclusion chromatography (TD-SEC) in order to verify the livingness of the polymerization. - Highlights: • SF surface containing hydroxyl and amino groups was firstly modified with MPS. • RAFT polymerizations of MMA and TBSiMA were studied. • TD-SEC was used to verify the livingness of the RAFT polymerization. • The grafted polymer chains enhance the thermal stability of the SF fibers. • The grafted fibers could be potentially promising candidates as antifouling agents

  9. 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.

  10. Biocompatibility of plasma-treated poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanofiber mats modified by silk fibroin for bone tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Unalan, Irem [Biomedical Technologies Department, Graduate School of Natural and Applied Sciences, Dokuz Eylul University, Izmir (Turkey); Colpankan, Oylum [Metallurgical and Materials Engineering Department, Faculty of Engineering, Dokuz Eylul University, Izmir (Turkey); Albayrak, Aylin Ziylan, E-mail: aylin.albayrak@deu.edu.tr [Metallurgical and Materials Engineering Department, Faculty of Engineering, Dokuz Eylul University, Izmir (Turkey); Gorgun, Cansu [Biomedical Technologies Department, Graduate School of Natural and Applied Sciences, Ege University, Izmir (Turkey); Urkmez, Aylin Sendemir [Biomedical Technologies Department, Graduate School of Natural and Applied Sciences, Ege University, Izmir (Turkey); Bioengineering Department, Faculty of Engineering, Ege University, Izmir (Turkey)

    2016-11-01

    The objective of this study was to produce biocompatible plasma-treated and silk-fibroin (SF) modified poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofiber mats. The mats were plasma-treated using O{sub 2} or N{sub 2} gas to increase their hydrophilicity followed by SF immobilization for the improvement of biocompatibility. Contact angle measurements and SEM showed increased hydrophilicity and no disturbed morphology, respectively. Cell proliferation assay revealed that SF modification together with N{sub 2} plasma (PS/N{sub 2}) promoted higher osteoblastic (SaOs-2) cell viability. Although, O{sub 2} plasma triggered more mineral formation on the mats, it showed poor cell viability. Consequently, the PS/N{sub 2} nanofiber mats would be a potential candidate for bone tissue engineering applications. - Highlights: • N{sub 2}-plasma treated and silk fibroin modified mats do not show hydrophobic recovery. • Biomineralization is better on O{sub 2}-plasma treated and silk fibroin modified mats. • SaOS-2 cells like to proliferate on N{sub 2}-plasma treated surfaces.

  11. 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.

  12. Effects of composite films of silk fibroin and graphene oxide on the proliferation, cell viability and mesenchymal phenotype of periodontal ligament stem cells.

    Science.gov (United States)

    Rodríguez-Lozano, F J; García-Bernal, D; Aznar-Cervantes, S; Ros-Roca, M A; Algueró, M C; Atucha, N M; Lozano-García, A A; Moraleda, J M; Cenis, J L

    2014-12-01

    In regenerative dentistry, stem cell-based therapy often requires a scaffold to deliver cells and/or growth factors to the injured site. Graphene oxide (GO) and silk fibroin (SF) are promising biomaterials for tissue engineering as they are both non toxic and promote cell proliferation. On the other hand, periodontal ligament stem cells (PDLSCs) are mesenchymal stem cells readily accessible with a promising use in cell therapy. The purpose of this study was to investigate the effects of composite films of GO, SF and GO combined with fibroin in the mesenchymal phenotype, viability, adhesion and proliferation rate of PDLSCs. PDLSCs obtained from healthy extracted teeth were cultured on GO, SF or combination of GO and SF films up to 10 days. Adhesion level of PDSCs on the different biomaterials were evaluated after 12 h of culture, whereas proliferation rate of cells was assessed using the MTT assay. Level of apoptosis was determined using Annexin-V and 7-AAD and mesenchymal markers expression of PDLSCs were analyzed by flow cytometry. At day 7 of culture, MTT experiments showed a high rate of proliferation of PDLSCs growing on GO films compared to the other tested biomaterials, although it was slightly lower than in plastic (control). However PDLSCs growing in fibroin or GO plus fibroin films showed a discrete proliferation. Importantly, at day 10 of culture it was observed a significant increase in PDLSCs proliferation rate in GO films compared to plastic (P < 0.05), as well as in GO plus fibroin compared to fibroin alone (P < 0.001). Flow cytometry analysis showed that culture of PDLSCs in fibroin, GO or GO plus fibroin films did not significantly alter the level of expression of the mesenchymal markers CD73, CD90 or CD105 up to 168 h, being the cell viability in GO even better than obtained in plastic. Our findings suggest that the combination of human dental stem cells/fibroin/GO based-bioengineered constructs have strong potential for their therapeutic

  13. Glycerin-Induced Conformational Changes in Bombyx mori Silk Fibroin Film Monitored by (13)C CP/MAS NMR and ¹H DQMAS NMR.

    Science.gov (United States)

    Asakura, Tetsuo; Endo, Masanori; Hirayama, Misaki; Arai, Hiroki; Aoki, Akihiro; Tasei, Yugo

    2016-09-09

    In order to improve the stiff and brittle characteristics of pure Bombyx mori (B. mori) silk fibroin (SF) film in the dry state, glycerin (Glyc) has been used as a plasticizer. However, there have been very limited studies on the structural characterization of the Glyc-blended SF film. In this study, (13)C Cross Polarization/Magic Angle Spinning nuclear magnetic resonance (CP/MAS NMR) was used to monitor the conformational changes in the films by changing the Glyc concentration. The presence of only 5 wt % Glyc in the film induced a significant conformational change in SF where Silk I* (repeated type II β-turn and no α-helix) newly appeared. Upon further increase in Glyc concentration, the percentage of Silk I* increased linearly up to 9 wt % Glyc and then tended to be almost constant (30%). This value (30%) was the same as the fraction of Ala residue within the Silk I* form out of all Ala residues of SF present in B. mori mature silkworm. The ¹H DQMAS NMR spectra of Glyc-blended SF films confirmed the appearance of Silk I* in the Glyc-blended SF film. A structural model of Glyc-SF complex including the Silk I* form was proposed with the guidance of the Molecular Dynamics (MD) simulation using ¹H-¹H distance constraints obtained from the ¹H Double-Quantum Magic Angle Spinning (DQMAS) NMR spectra.

  14. Silk fibroin film from golden-yellow Bombyx mori is a biocomposite that contains lutein and promotes axonal growth of primary neurons.

    Science.gov (United States)

    Pistone, Assunta; Sagnella, Anna; Chieco, Camilla; Bertazza, Gianpaolo; Varchi, Greta; Formaggio, Francesco; Posati, Tamara; Saracino, Emanuela; Caprini, Marco; Bonetti, Simone; Toffanin, Stefano; Di Virgilio, Nicola; Muccini, Michele; Rossi, Federica; Ruani, Giampiero; Zamboni, Roberto; Benfenati, Valentina

    2016-05-01

    The use of doped silk fibroin (SF) films and substrates from Bombyx mori cocoons for green nanotechnology and biomedical applications has been recently highlighted. Cocoons from coloured strains of B. mori, such as Golden-Yellow, contain high levels of pigments that could have a huge potential for the fabrication of SF based biomaterials targeted to photonics, optoelectronics and neuroregenerative medicine. However, the features of extracted and regenerated SF from cocoons of B. mori Golden-Yellow strain have never been reported. Here we provide a chemophysical characterization of regenerated silk fibroin (RSF) fibers, solution, and films obtained from cocoons of a Golden-Yellow strain of B. mori, by SEM, (1) H-NMR, HPLC, FT-IR, Raman and UV-Vis spectroscopy. We found that the extracted solution and films from B. mori Golden-Yellow fibroin displayed typical Raman spectroscopic and optical features of carotenoids. HPLC-analyses revealed that lutein was the carotenoid contained in the fiber and RSF biopolymer from yellow cocoons. Notably, primary neurons cultured on yellow SF displayed a threefold higher neurite length than those grown of white SF films. The results we report pave the way to expand the potential use of yellow SF in the field of neuroregenerative medicine and provide green chemistry approaches in biomedicine. © 2016 Wiley Periodicals, Inc.

  15. Antimicrobial and antioxidant surface modification toward a new silk-fibroin (SF)-L-Cysteine material for skin disease management

    Science.gov (United States)

    Nogueira, Frederico; Granadeiro, Luíza; Mouro, Claudia; Gouveia, Isabel C.

    2016-02-01

    A novel dressing material - silk fibroin fabric (SF)-L-Cysteine (L-Cys) - is here developed to be used as standard treatment for atopic dermatitis (AD), which combines comfort, thermic, and tensile strength properties of silk materials with antioxidant and antimicrobial effects of L-Cys. A careful understanding about the linking strategies is needed in order not to compromise the bioavailability of L-Cys and deplenish its bioactivity. Durability was also addressed through washing cycles and compared with hospital requirements, according to international Standard EN ISO 105-C06:2010. The present research also analyze the interactions between Staphylococcus aureus and SF-L-Cys under simulating conditions of AD and demonstrated the effectiveness of a double covalent grafting, with the importance of SF tyrosine (Tyr) covalent linkage with L-Cys (SF-g-L-Cys/Tyr-g-L-Cys) even after several washing cycles, twenty five, whereas for a disposable application a single covalent mechanism of grafting L-Cys proved to be sufficient (SF-g-L-Cys). Results showed effective antimicrobial activities exhibiting higher inhibition ratios of 98.65% for SF-g-L-Cys after 5 washing cycles, whereas 97.55% for SF-g-L-Cys/Tyr-g-L-Cys after 25 washing cycles, both at pH 9.5 grafting strategy. Furthermore, it is also reported a non-protumoral effect of L-Cys. A new advance is herein achieved at the world of medical antimicrobial textiles tailored to address wound moisture environment and exudate self-cleaning, which may open novel applications as complementary therapy for AD disease.

  16. Super-paramagnetic responsive silk fibroin/chitosan/magnetite scaffolds with tunable pore structures for bone tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Aliramaji, Shamsa; Zamanian, Ali, E-mail: a-zamanian@merc.ac.ir; Mozafari, Masoud

    2017-01-01

    Tissue engineering is a promising approach in repairing damaged tissues. During the last few years, magnetic nanoparticles have been of great interest in this field of study due to their controlled responsive characteristics in specific external magnetic fields. In this study, after synthesizing iron oxide (magnetite) nanoparticles through a reverse coprecipitation method, silk fibroin/chitosan-based magnetic scaffolds were prepared using different amounts of magnetite nanoparticles (0, 0.5, 1 and 2%) by freeze-casting method. The physicochemical activity of the scaffolds was monitored in phosphate-buffered saline (PBS) solution to determine the biodegradation and swelling behaviors. The stability of the magnetite nanoparticles in the fabricated scaffolds was determined by atomic absorption spectroscopy (AAS). Moreover, the cellular activity of the magnetic scaffolds was examined under a static magnetic field. The results showed that the lamellar structured scaffolds having MNPs in the walls could not affect the final structure and deteriorate the biological characteristics of the scaffolds, while the ability of magnetic responsivity was added to the scaffolds. This study warrants further pre-clinical and clinical evaluations. - Highlights: • Based on TEM micrograph and Rietveld refinement the particle size of MNPs was approximately 12 nm. • The water absorption of silk scaffolds increases by the addition of chitosan content. • Addition of 0.5 wt% MNPs led to decrease in scaffolds degradation and number of living cells. • By increasing the MNPs from 0.5 to 1 and 2, the degradation rate and living cells increased. • In scaffolds with 2 wt% MNPs cell attachment is slightly better than those of 0.5 wt%.

  17. 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

  18. The ESR signals in silk fibroin and wool keratin under both the effect of UV-irradiation and without any external effects and the formation of free radicals.

    Science.gov (United States)

    Mamedov, Sh V; Aktas, B; Cantürk, M; Aksakal, B; Alekperov, V; Bülbül, F; Yilgin, R; Aslanov, R B

    2002-08-01

    ESR studies have been done on natural and UV-irradiated silk fibroins and wool keratins at the temperature range of -196 degrees C to 20 C. The intensities of ESR signals obtained from the irradiated samples at -196 C remarkably increase with respect to those of natural samples. While the signals mainly consist of triplet peaks at -196 C. a doublet arises around the room temperatures. For the first time, at room temperature without any external effect the complicated ESR spectra of fibrous proteins (wool keratin and silk fibroin) whose components are as follows have been observed: (1) (for white wool keratin) a central doublet with deltaHm = 1.1 mT and g = 2.0075; deltaHm = 5mT and g = 2.1911; (2) a wide peak with deltaHm approximately 66 mT and g approximately 2.1575; (3) the 'sulfur' peak given in the literature with deltaHm = 2.2 mT and g = 2.0218; (4) the signal with deltaHm = 0.6 mT and g = 2.0065, and for silk fibroin, (a) a very wide signal with deltaHm approximately 70 mT and g approximately 2.084; (b) a very sharp signal with deltaHm approximately 1.1 mT and g approximately 2.01; and (c) relatively narrower signal with deltaHm approximately 5 mT and g approximately 2.336. It has been shown by recombination kinetic method that 30-50% of the free radicals formed by UV-irradiation do not undergo recombination up to 220 degrees C and 15 degrees C for silk libroin and wool keratin, respectively, even they keep their concentration constant for long period of time (weeks, months, even longer). In this article, considering above-mentioned results, the mechanism of signals observed in natural wool keratin and silk fibroin without any external effects is examined. We can briefly explain the role of the subject of the article, by considering fibrous proteins and some applications of the reactions by free radical occurring in these proteins tinder the effects of different factors in medicine and biology and the important role of oxidation and the other kinds of

  19. 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

  20. Composite biodegradable biopolymer coatings of silk fibroin - Poly(3-hydroxybutyric-acid-co-3-hydroxyvaleric-acid) for biomedical applications

    Science.gov (United States)

    Miroiu, Floralice Marimona; Stefan, Nicolaie; Visan, Anita Ioana; Nita, Cristina; Luculescu, Catalin Romeo; Rasoga, Oana; Socol, Marcela; Zgura, Irina; Cristescu, Rodica; Craciun, Doina; Socol, Gabriel

    2015-11-01

    Composite silk fibroin-poly(3-hydroxybutyric-acid-co-3-hydroxyvaleric-acid) (SF-PHBV) biodegradable coatings were grown by Matrix Assisted Pulsed Laser Evaporation on titanium substrates. Their physico-chemical properties and particularly the degradation behavior in simulated body fluid at 37 °C were studied as first step of applicability in local controlled release for tissue regeneration applications. SF and PHBV, natural biopolymers with excellent biocompatibility, but different biodegradability and tensile strength properties, were combined in a composite to improve their properties as coatings for biomedical uses. FTIR analyses showed the stoichiometric transfer from targets to coatings by the presence in the spectra of the main absorption maxima characteristic of both polymers. XRD investigations confirmed the FTIR results showing differences in crystallization behavior with respect to the SF and PHBV content. Contact angle values obtained through wettability measurements indicated the MAPLE deposited coatings were highly hydrophilic; surfaces turning hydrophobic with the increase of the PHBV component. Degradation assays proved that higher PHBV contents resulted in enhanced resistance and a slower degradation rate of composite coatings in SBF. Distinct drug-release schemes could be obtained by adjusting the SF:PHBV ratio to controllably tuning the coatings degradation rate, from rapid-release formulas, where SF predominates, to prolonged sustained ones, for larger PHBV content.

  1. Strong and biocompatible three-dimensional porous silk fibroin/graphene oxide scaffold prepared by phase separation.

    Science.gov (United States)

    Wang, Shu-Dong; Ma, Qian; Wang, Ke; Ma, Pi-Bo

    2018-05-01

    Silk fibroin (SF) is blended with graphene oxide (GO) to prepare the strong and biocompatible three dimensional porous SF/GO blended scaffold via phase separation. GO could be well dispersed in SF solution and GO could also be well distributed in the SF scaffold. Furthermore, the introduction of GO can lead to structural change in the bended scaffold. Higher concentration of GO resulted in more compact structure and smaller pore size of the composite scaffolds without decreasing their porosity. Scanning electron microscopy and energy dispersive spectrometry results also reveal that SF and GO are homogeneous blended together. Analysis of chemical structures of the scaffold shows that addition of GO do not affect the crystalline structure of SF and it is evenly blended with SF. The blended scaffold has significantly higher breaking strength than the pure SF scaffold. In vitro study indicates that both pure SF scaffold and SF/GO composite scaffold support growth and proliferation of MC3T3-E1 osteoprogenitor cells. However, the addition of GO contribute to the proliferation of MC3T3-E1 osteoprogenitor. The testing results show that the blended scaffold is an appropriate candidate for tissue engineering. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Silk fibroin/gelatin-chondroitin sulfate-hyaluronic acid effectively enhances in vitro chondrogenesis of bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Sawatjui, Nopporn; Damrongrungruang, Teerasak; Leeanansaksiri, Wilairat; Jearanaikoon, Patcharee; Hongeng, Suradej; Limpaiboon, Temduang

    2015-01-01

    Tissue engineering is becoming promising for cartilage repair due to the limited self-repair capacity of cartilage tissue. We previously fabricated and characterized a three-dimensional silk fibroin/gelatin-chondroitin sulfate-hyaluronic acid (SF-GCH) scaffold and showed that it could promote proliferation of human bone marrow mesenchymal stem cells (BM-MSCs). This study aimed to evaluate its biological performance as a new biomimetic material for chondrogenic induction of BM-MSCs in comparison to an SF scaffold and conventional pellet culture. We found that the SF-GCH scaffold significantly enhanced the proliferation and chondrogenic differentiation of BM-MSCs compared to the SF scaffold and pellet culture in which the production of sulfated glycoaminoglycan was increased in concordance with the up-regulation of chondrogenic-specific gene markers. Our findings indicate the significant role of SF-GCH by providing a supportive structure and the mimetic cartilage environment for chondrogenesis which enables cartilage regeneration. Thus, our fabricated SF-GCH scaffold may serve as a potential biomimetic material for cartilage tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Nano-scaled hydroxyapatite/silk fibroin sheets support osteogenic differentiation of rat bone marrow mesenchymal cells

    International Nuclear Information System (INIS)

    Tanaka, Toshimitsu; Hirose, Motohiro; Kotobuki, Noriko; Ohgushi, Hajime; Furuzono, Tsutomu; Sato, Junichi

    2007-01-01

    A novel biomaterial that was composed of nano-scaled sintered hydroxyapatite (HAp) and silk fibroin (SF) was fabricated. We cultured rat marrow mesenchymal cells (MMCs) on this biomaterial (nano-HAp/SF sheet), on bare SF sheets, and on tissue culture polystyrene (TCPS) dishes as controls, then evaluated cell adhesion, proliferation, and differentiation of the MMCs. After 1 h of culture, a large number of viable cells were observed on the nano-HAp/SF sheets in comparison to the controls. In addition, after 3 h of culture, the morphology of the cells on the nano-HAp/SF sheets was quite different from that on the SF sheets. MMCs extrude their cytoplasmic processes to nano-HAp particles and are well attached to the sheets. After 14 days of culture, under osteogenic conditions, the alkaline phosphatase (ALP) activity and bone-specific osteocalcin secretion of the cells on nano-HAp/SF sheets were higher than were those on the controls. These results indicated that the surface of the nano-HAp/SF sheets is covered with appropriate HAp crystal for MMC adhesion/proliferation and that the sheets effectively support the osteogenic differentiation of MMCs. Therefore, the nano-HAp/SF sheet is an effective biomaterial that is applicable in bone reconstruction surgery

  4. The anticoagulant ability of ferulic acid and its applications for improving the blood compatibility of silk fibroin

    Energy Technology Data Exchange (ETDEWEB)

    Wang Song; Gao Zhen; Chen Xiaomeng; Lian Xiaojie; Zhu Hesun [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Zheng Jun; Sun Lizhong [Department of Cardiac Surgery, Cardiovascular Institute and Fu Wai Hospital, CAMS and PUMC, Beijing 100037 (China)], E-mail: wangsongbit@hotmail.com

    2008-12-15

    The hemocompatibility of silk fibroin (SF) was improved with ferulic acid (FA) by graft polymerization. Ferulic acid is an active ingredient of many Chinese herbal medicines, such as Chuanxiong (Rhizoma ligustici wallichii), Danggui (Angelica sinensis) and Awei (Asafoetida giantfennel), which have been used to treat cardiovascular diseases by Chinese physicians for thousands of years. The inhibitory functions of FA on blood coagulation and erythrocyte agglutination were first characterized by a Lee-White test tube method and a micropipette technique, respectively. Then, FA was immobilized on SF by graft polymerization and the surface composition of modified SF was characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR), x-ray photoelectron spectroscopy (XPS) and optical microscopy. The anticoagulant activity of modified SF was assessed, respectively, by in vitro clotting time measurements on a photo-optical clot detection instrument and with the Lee-White test tube method. The test results indicated that in comparison to untreated SF, the anticoagulant activity of modified SF has been improved significantly. Moreover, the SF surface composition is altered by FA but its {beta}-sheet conformation is not disturbed.

  5. Bone Morphogenic Protein-2 (rhBMP2)-Loaded Silk Fibroin Scaffolds to Enhance the Osteoinductivity in Bone Tissue Engineering

    Science.gov (United States)

    Du, Guang-Yu; He, Sheng-Wei; Sun, Chuan-Xiu; Mi, Li-Dong

    2017-10-01

    There is an increasing demand for formulations of silk fibroin (SF) scaffolds in biomedical applications. SF was crosslinked via glutaraldehyde with osteoinductive recombinant human bone morphogenic protein-2 (rhBMP2) of different ratios viz. (i) 3% SF with no rhBMP2 (SF), (ii) 3% SF with equal amount of rhBMP2 (SF+BMP2), and (iii) 12% SF with 3% of rhBMP2 (4SF+BMP2), and these solutions were used in electrospinning-based fabrication of nanoscaffolds for evaluating increased osteoinductive potential of SF scaffolds with rhBMP2. Stress-strain relationship suggested there is no loss in mechanical strength of fibers with addition of rhBMP2, and mechanical strength of scaffold was improved with increase in concentration of SF. rhBMP2 association increased the water retention capacity of scaffold as evident from swelling studies. Viability of hMSCs was found to be higher in conjugated scaffolds, and scaffolds do not exhibit any cytotoxicity towards guest cells. Cells were found to have higher alkaline phosphatase activity in conjugated scaffolds under in vitro and in vivo conditions which establishes the increased osteoinductivity of the novel construct. The scaffolds were found to be effective for in vivo bone formation as well.

  6. Silk fibroin/gelatin–chondroitin sulfate–hyaluronic acid effectively enhances in vitro chondrogenesis of bone marrow mesenchymal stem cells

    International Nuclear Information System (INIS)

    Sawatjui, Nopporn; Damrongrungruang, Teerasak; Leeanansaksiri, Wilairat; Jearanaikoon, Patcharee; Hongeng, Suradej; Limpaiboon, Temduang

    2015-01-01

    Tissue engineering is becoming promising for cartilage repair due to the limited self-repair capacity of cartilage tissue. We previously fabricated and characterized a three-dimensional silk fibroin/gelatin–chondroitin sulfate–hyaluronic acid (SF–GCH) scaffold and showed that it could promote proliferation of human bone marrow mesenchymal stem cells (BM-MSCs). This study aimed to evaluate its biological performance as a new biomimetic material for chondrogenic induction of BM-MSCs in comparison to an SF scaffold and conventional pellet culture. We found that the SF–GCH scaffold significantly enhanced the proliferation and chondrogenic differentiation of BM-MSCs compared to the SF scaffold and pellet culture in which the production of sulfated glycoaminoglycan was increased in concordance with the up-regulation of chondrogenic-specific gene markers. Our findings indicate the significant role of SF–GCH by providing a supportive structure and the mimetic cartilage environment for chondrogenesis which enables cartilage regeneration. Thus, our fabricated SF–GCH scaffold may serve as a potential biomimetic material for cartilage tissue engineering. - Highlights: • SF–GCH scaffold enhances proliferation and chondrogenic differentiation of BM-MSCs. • SF–GCH acts as a supportive and biomimetic material for BM-MSC chondrogenesis. • SF–GCH is a potential biomimetic scaffold suitable for cartilage tissue engineering

  7. Silk fibroin/gelatin–chondroitin sulfate–hyaluronic acid effectively enhances in vitro chondrogenesis of bone marrow mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Sawatjui, Nopporn [Biomedical Sciences, Graduate School, Khon Kaen University, Khon Kaen 40002 (Thailand); Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Damrongrungruang, Teerasak [Department of Oral Diagnosis, Faculty of Dentistry, Khon Kaen University, Khon Kaen 40002 (Thailand); Leeanansaksiri, Wilairat [Stem Cell Therapy and Transplantation Research Group, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); School of Microbiology, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Jearanaikoon, Patcharee [Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Hongeng, Suradej [Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400 (Thailand); Limpaiboon, Temduang, E-mail: temduang@kku.ac.th [Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2015-07-01

    Tissue engineering is becoming promising for cartilage repair due to the limited self-repair capacity of cartilage tissue. We previously fabricated and characterized a three-dimensional silk fibroin/gelatin–chondroitin sulfate–hyaluronic acid (SF–GCH) scaffold and showed that it could promote proliferation of human bone marrow mesenchymal stem cells (BM-MSCs). This study aimed to evaluate its biological performance as a new biomimetic material for chondrogenic induction of BM-MSCs in comparison to an SF scaffold and conventional pellet culture. We found that the SF–GCH scaffold significantly enhanced the proliferation and chondrogenic differentiation of BM-MSCs compared to the SF scaffold and pellet culture in which the production of sulfated glycoaminoglycan was increased in concordance with the up-regulation of chondrogenic-specific gene markers. Our findings indicate the significant role of SF–GCH by providing a supportive structure and the mimetic cartilage environment for chondrogenesis which enables cartilage regeneration. Thus, our fabricated SF–GCH scaffold may serve as a potential biomimetic material for cartilage tissue engineering. - Highlights: • SF–GCH scaffold enhances proliferation and chondrogenic differentiation of BM-MSCs. • SF–GCH acts as a supportive and biomimetic material for BM-MSC chondrogenesis. • SF–GCH is a potential biomimetic scaffold suitable for cartilage tissue engineering.

  8. Electrophoretic-deposited novel ternary silk fibroin/graphene oxide/hydroxyapatite nanocomposite coatings on titanium substrate for orthopedic applications

    Science.gov (United States)

    Li, Ming; Xiong, Pan; Mo, Maosong; Cheng, Yan; Zheng, Yufeng

    2016-09-01

    The combination of graphene oxide (GO) with robust mechanical property, silk fibroin (SF) with fascinating biological effects and hydroxyapatite (HA) with superior osteogenic activity is a competitive approach to make novel coatings for orthopedic applications. Herein, the feasibility of depositing ternary SF/GO/HA nanocomposite coatings on Ti substrate was firstly verified by exploiting electrophoretic nanotechnology, with SF being used as both a charging additive and a dispersion agent. The surface morphology, microstructure and composition, in vitro hemocompatibility and in vitro cytocompatibility of the resulting coatings were investigated by SEM, Raman, FTIR spectra and biocompatibility tests. Results demonstrated that GO, HA and SF could be co-deposited with a uniform, smooth thin-film morphology. The hemolysis rate analysis and the platelet adhesion test indicated good blood compatibility of the coatings. The human osteosarcoma MG63 cells displayed well adhesion and proliferation behaviors on the prepared coatings, with enhanced ALP activities. The present study suggested that SF/GO/HA nanocomposite coatings could be a promising candidate for the surface functionalization of biomaterials, especially as orthopedic implant coating.

  9. A simple semi-quantitative approach studying the in vivo degradation of regenerated silk fibroin scaffolds with different pore sizes.

    Science.gov (United States)

    Guo, Yongwei; Chen, Zhongchun; Wen, Jianchuan; Jia, Minghui; Shao, Zhengzhong; Zhao, Xia

    2017-10-01

    The biocompatibility and in vivo degradation rate of biomaterials represent critical control points in the long-term success of scaffolds for tissue restoration. In this study, new three-dimensional (3D) regenerated silk fibroin scaffolds (RSFs) were prepared by the freezing-defrosting procedure, and then were implanted beneath the dorsal skin of rats. This study aims to develop a kinetic semi-quantitative approach to assess in vivo degradation rate and biocompatibility of this kind of RSFs with different pore sizes for the first time, and to evaluate the relationship between the biodegradation and tissue responses by measuring the thickness of residual scaffolds, fibrous capsules and infiltrated tissues through integrated techniques of histology, optical imaging and image analysis. Our results showed that scaffolds with both pore sizes (74.35±10.84μm and 139.23±44.93μm, respectively) were well tolerated by host animals and pore size was found to be the rate limiting factor to the biodegradation in the subcutaneous implantation model. In addition, the biodegradation of RSFs was inflammation-mediated to a certain degree and fibroblasts may play a critical role in this process. Overall, such semi-quantitative approach was demonstrated to be a simple and effective method to assess the in vivo degradation rate, and the prepared RSFs were presented to have promising potential in tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Production of Composite Scaffold Containing Silk Fibroin, Chitosan, and Gelatin for 3D Cell Culture and Bone Tissue Regeneration.

    Science.gov (United States)

    Li, Jianqing; Wang, Qiuke; Gu, Yebo; Zhu, Yu; Chen, Liang; Chen, Yunfeng

    2017-11-08

    BACKGROUND Bone tissue engineering, a powerful tool to treat bone defects, is highly dependent on use of scaffolds. Both silk fibroin (SF) and chitosan (Cs) are biocompatible and actively studied for reconstruction of tissue engineering. Gelatin (Gel) is also widely applied in the biomedical field due to its low antigenicity and physicochemical stability. MATERIAL AND METHODS In this study, 4 different types of scaffolds were constructed - SF, SF/Cs, SF/Gel, and SF/Cs/Gel - and we compared their physical and chemical properties as well as biological characterization of these scaffolds to determine the most suitable scaffold for use in bone regeneration. First, these scaffolds were produced via chemical cross-linking method and freeze-drying technique. Next, the characterization of internal structure was studied using scanning electron microscopy and the porosity was evaluated by liquid displacement method. Then, we compared physicochemical properties such as water absorption rate and degradation property. Finally, MC3T3-E1 cells were inoculated on the scaffolds to study the biocompatibility and osteogenesis of the three-dimensional (3D) scaffolds in vitro. RESULTS The composite scaffold formed by all 3 components was the best for use in bone regeneration. CONCLUSIONS We conclude that the best scaffold among the 4 studied for MC3T3-E1 cells is our SF/Cs/Gel scaffold, suggesting a new choice for bone regeneration that can be used to treat bone defects or fractures in clinical practice.

  11. Immobilized Lentivirus Vector on Chondroitin Sulfate-Hyaluronate Acid-Silk Fibroin Hybrid Scaffold for Tissue-Engineered Ligament-Bone Junction

    Directory of Open Access Journals (Sweden)

    Liguo Sun

    2014-01-01

    Full Text Available The lack of a fibrocartilage layer between graft and bone remains the leading cause of graft failure after anterior cruciate ligament (ACL reconstruction. The objective of this study was to develop a gene-modified silk cable-reinforced chondroitin sulfate-hyaluronate acid-silk fibroin (CHS hybrid scaffold for reconstructing the fibrocartilage layer. The scaffold was fabricated by lyophilizing the CHS mixture with braided silk cables. The scanning electronic microscopy (SEM showed that microporous CHS sponges were formed around silk cables. Each end of scaffold was modified with lentiviral-mediated transforming growth factor-β3 (TGF-β3 gene. The cells on scaffold were transfected by bonded lentivirus. In vitro culture demonstrated that mesenchymal stem cells (MSCs on scaffolds proliferated vigorously and produced abundant collagen. The transcription levels of cartilage-specific genes also increased with culture time. After 2 weeks, the MSCs were distributed uniformly throughout scaffold. Deposited collagen was also found to increase. The chondral differentiation of MSCs was verified by expressions of collagen II and TGF-β3 genes in mRNA and protein level. Histology also confirmed the production of cartilage extracellular matrix (ECM components. The results demonstrated that gene-modified silk cable-reinforced CHS scaffold was capable of supporting cell proliferation and differentiation to reconstruct the cartilage layer of interface.

  12. Rational design of a high-strength bone scaffold platform based on in situ hybridization of bacterial cellulose/nano-hydroxyapatite framework and silk fibroin reinforcing phase.

    Science.gov (United States)

    Jiang, Pei; Ran, Jiabing; Yan, Pan; Zheng, Lingyue; Shen, Xinyu; Tong, Hua

    2018-02-01

    Bacterial cellulose/hydroxyapatite (BC/HAp) composite had favourable bioaffinity but its poor mechanical strength limited its widespread applications in bone tissue engineering (BTE). Silk fibroin, which possesses special crystalline structure, has been widely used as organic reinforcing material, and different SFs have different amino acid sequences, which exhibit different bioaffinity and mechanical properties. In this regard, bacterial cellulose-Antheraea yamamai silk fibroin/hydroxyapatite (BC-AYSF/HAp), bacterial cellulose-Bombyx mori silk fibroin/hydroxyapatite (BC-BMSF/HAp), and BC/HAp nano-composites were synthesized via a novel in situ hybridization method. Compared with BC/HAp and BC-BMSF/HAp, the BC-AYSF/HAp exhibited better interpenetration, which may benefit for the transportation of nutrients and wastes, the adhesion of cells as well. Additionally, the BC-AYSF/HAp also presented superior thermal stability than the other two composites revealed by differential thermal analysis (DTA) and thermogravimetric analysis (TGA). Compression testing indicated that the mechanical strength of BC-BMSF/HAp was greatly reinforced compared with BC/HAp and was even a little higher than that of BC-AYSF/HAp. Tensile testing showed that BC-AYSF/HAp possesses extraordinary mechanical properties with a higher elastic modulus at low strain and higher fracture strength simultaneously than the other two composites. In vitro cell culture exhibited that MC3T3-E1 cells on the BC-AYSF/HAp membrane took on higher proliferative potential than those on the BC-BMSF/HAp membrane. These results suggested that compared with BC-BMSF/HAp, the BC-AYSF/HAp composite was more appropriate as an ideal bone scaffold platform or biomedical membrane to be used in BTE.

  13. One-pot, green, rapid synthesis of flowerlike gold nanoparticles/reduced graphene oxide composite with regenerated silk fibroin as efficient oxygen reduction electrocatalysts.

    Science.gov (United States)

    Xu, Shengjie; Yong, Liu; Wu, Peiyi

    2013-02-01

    Flowerlike gold nanoparticles (Au NPs)/reduced graphene oxide (RGO) composites were fabricated by a facile, one-pot, environmentally friendly method in the presence of regenerated silk fibroin (RSF). The influences of reaction time, temperature, and HAuCl(4): RGO ratio on the morphology of Au NPs loaded on RGO sheets were discussed and a tentative mechanism for the formation of flowerlike Au NPs/RGO composite was proposed. In addition, the flowerlike Au NPs/RGO composite showed superior catalytic performance for oxygen reduction reaction (ORR) to Au/RGO composites with other morphologies. Our work provides an alternative facile and green approach to synthesize functional metal/RGO composites.

  14. Intestinal anti-inflammatory effects of RGD-functionalized silk fibroin nanoparticles in trinitrobenzenesulfonic acid-induced experimental colitis in rats

    Directory of Open Access Journals (Sweden)

    Rodriguez-Nogales A

    2016-11-01

    Full Text Available Alba Rodriguez-Nogales,1 Francesca Algieri,1 Laura De Matteis,2 A. Abel Lozano-Perez,3 Jose Garrido-Mesa,1 Teresa Vezza,1 J M. de la Fuente,2 Jose Luis Cenis,3 Julio Gálvez,1,* Maria Elena Rodriguez-Cabezas1,* 1CIBER-EHD, Department of Pharmacology, ibs.GRANADA, Center for Biomedical Research, University of Granada, Granada, 2Instituto de Nanociencia de Aragón, Universidad de Zaragoza, Zaragoza, 3Department of Biotechnology, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario, Murcia, Spain *These authors contributed equally to this work Background: Current treatment of inflammatory bowel disease is based on the use of immunosuppressants or anti-inflammatory drugs, which are characterized by important side effects that can limit their use. Previous research has been performed by administering these drugs as nanoparticles that target the ulcerated intestinal regions and increase their bioavailability. It has been reported that silk fibroin can act as a drug carrier and shows anti-inflammatory properties. Purpose: This study was designed to enhance the interaction of the silk fibroin nanoparticles (SFNs with the injured intestinal tissue by functionalizing them with the peptide motif RGD (arginine–glycine–aspartic acid and to evaluate the intestinal anti-inflammatory properties of these RGD-functionalized silk fibroin nanoparticles (RGD-SFNs in the trinitrobenzenesulfonic acid (TNBS model of rat colitis. Materials and methods: SFNs were prepared by nanoprecipitation in methanol, and the linear RGD peptide was linked to SFNs using glutaraldehyde as the crosslinker. The SFNs (1 mg/rat and RGD-SFNs (1 mg/rat were administered intrarectally to TNBS-induced colitic rats for 7 days. Results: The SFN treatments ameliorated the colonic damage, reduced neutrophil infiltration, and improved the compromised oxidative status of the colon. However, only the rats treated with RGD-SFNs showed a significant reduction in the

  15. ToF-SIMS characterization of silk fibroin and polypyrrole composite actuators

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, Nathan P.; Severt, Sean Y.; Wang, Zhaoying; Fengel, Carly V.; Larson, Jesse D.; Zhu, Zihua; Murphy, Amanda R.; Leger., Janelle M.

    2015-11-01

    Biocompatible materials capable of controlled actuation under biologically relevant conditions are in high demand for use in a number of biomedical applications. Recently, we demonstrated that a composite material composed of silk biopolymer and the conducting polymer poly(pyrrole) can bend under an applied voltage using a simple bilayer device. Here we present further characterization of these bilayer actuators using time of flight secondary ion mass spectrometry, and provide clarification on the mechanism of actuation and factors affecting device performance and stability. We will discuss the results of this study in the context of strategies for optimization of device performance.

  16. Anti-EGFR-iRGD recombinant protein conjugated silk fibroin nanoparticles for enhanced tumor targeting and antitumor efficiency

    Directory of Open Access Journals (Sweden)

    Bian X

    2016-05-01

    Full Text Available Xinyu Bian,* Puyuan Wu,* Huizi Sha, Hanqing Qian, Qing Wang, Lei Cheng, Yang Yang, Mi Yang, Baorui LiuComprehensive Cancer Center of Drum-Tower Hospital, Medical School of Nanjing University, Clinical Cancer Institute of Nanjing University, Nanjing, People’s Republic of China*These authors contributed equally to this workAbstract: In this study, we report a novel kind of targeting with paclitaxel (PTX-loaded silk fibroin nanoparticles conjugated with iRGD–EGFR nanobody recombinant protein (anti-EGFR-iRGD. The new nanoparticles (called A-PTX-SF-NPs were prepared using the carbodiimide-mediated coupling procedure and their characteristics were evaluated. The cellular cytotoxicity and cellular uptake of A-PTX-SF-NPs were also investigated. The results in vivo suggested that NPs conjugated with the recombinant protein exhibited more targeting and anti-neoplastic property in cells with high EGFR expression. In the in vivo antitumor efficacy assay, the A-PTX-SF-NPs group showed slower tumor growth and smaller tumor volumes than PTX-SF-NPs in a HeLa xenograft mouse model. A real-time near-infrared fluorescence imaging study showed that A-PTX-SF-NPs could target the tumor more effectively. These results suggest that the anticancer activity and tumor targeting of A-PTX-SF-NPs were superior to those of PTX-SF-NPs and may have the potential to be used for targeted delivery for tumor therapies. Keywords: EGFR, nanobody, iRGD, recombinant protein, targeting drug carriers, antitumor efficiency

  17. 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.

  18. Contribution to the ultrastructural study of silk-excretion cells and autoradiographic analysis of intracellular fibroin transport in Bombyx mori L

    International Nuclear Information System (INIS)

    Couble, Pierre.

    1974-01-01

    It is much easier to study the mechanisms involved in the synthesis and exportation of extracellular proteins in the biological material chosen is highly differentiated. The silk-excretion gland of the silkworm is ideal in this respect because during the larva period, especially at the end of the 5th and last stage, the cells at the rear (excreting tube) synthesize and export massive quantities of a single protein: fibroin. These phenomena were explored by a cytological study carried out mainly by electron microscopy and autoradiography. The results obtained are given. They relate first of all to the morphological development of the secretion tube cells from the end of the 4th larva stage to the spinning of the cocoon, and contribute new information on the cell changes during the 4th slough and the end of the 5th age. They also concern intracellular fibroin transport which is proved to take place through the Golgi apparatus, and finally the possible role of the microtubules and microfilaments in fibroin transport and secretion. On this last point the results so far constitute only, a preliminary approach which justifie no final conclusions; they merely suggest that the microfilaments of the apical region are involved in the secretion process [fr

  19. Impedimetric PSA aptasensor based on the use of a glassy carbon electrode modified with titanium oxide nanoparticles and silk fibroin nanofibers.

    Science.gov (United States)

    Benvidi, Ali; Banaei, Maryam; Tezerjani, Marzieh Dehghan; Molahosseini, Hosein; Jahanbani, Shahriar

    2017-12-14

    This article describes an impedimetric aptasensor for the prostate specific antigen (PSA), a widely accepted prostate cancer biomarker. A glassy carbon electrode (GCE) was modified with titanium oxide nanoparticles (TiO 2 ) and silk fibroin nanofiber (SF) composite. The aptasensor was obtained by immobilizing a PSA-binding aptamer on the AuNP-modified with 6-mercapto-1-hexanol. The single fabrication steps were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The assay has two linear response ranges (from 2.5 fg.mL -1 to 25 pg.mL -1 , and from 25 pg.mL -1 to 25 ng.mL -1 ) and a 0.8 fg.mL -1 detection limit. After optimization of experimental conditions, the sensor is highly selective for PSA over bovine serum albumin and lysozyme. It was successfully applied to the detection of PSA in spiked serum samples. Graphical abstract Schematic of the fabrication of an aptasensor for the prostate specific antigen (PSA). It is based on the use of a glassy carbon electrode modified with gold nanoparticles and titanium oxide-silk fibroin. The immobilization process of aptamer and interaction with PSA were followed by electrochemical impedance spectroscopy technique.

  20. Low pressure-induced secondary structure transitions of regenerated silk fibroin in its wet film studied by time-resolved infrared spectroscopy.

    Science.gov (United States)

    He, Zhipeng; Liu, Zhao; Zhou, Xiaofeng; Huang, He

    2018-06-01

    The secondary structure transitions of regenerated silk fibroin (RSF) under different external perturbations have been studied extensively, except for pressure. In this work, time-resolved infrared spectroscopy with the attenuated total reflectance (ATR) accessory was employed to follow the secondary structure transitions of RSF in its wet film under low pressure. It has been found that pressure alone is favorable only to the formation of β-sheet structure. Under constant pressure there is an optimum amount of D 2 O in the wet film (D 2 O : film = 2:1) so as to provide the optimal condition for the reorganization of the secondary structure and to have the largest formation of β-sheet structure. Under constant amount of D 2 O and constant pressure, the secondary structure transitions of RSF in its wet film can be divided into three stages along with time. In the first stage, random coil, α-helix, and β-turn were quickly transformed into β-sheet. In the second stage, random coil and β-turn were relatively slowly transformed into β-sheet and α-helix, and the content of α-helix was recovered to the value prior to the application of pressure. In the third and final stage, no measurable changes can be found for each secondary structure. This study may be helpful to understand the secondary structure changes of silk fibroin in silkworm's glands under hydrostatic pressure. © 2018 Wiley Periodicals, Inc.

  1. Silk fibroin-antigenic peptides-YVO{sub 4}:Eu{sup 3+} nanostructured thin films as sensors for hepatitis C

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Lais R. [Institute of Chemistry, São Paulo State University, UNESP, CP355, Araraquara, SP 14801-970 (Brazil); Moraes, Marli L. [Institute of Science and Technology, Federal University of São Paulo, UNIFESP, São José dos Campos, SP 12231-280 (Brazil); Nigoghossian, Karina; Peres, Maristela F.S. [Institute of Chemistry, São Paulo State University, UNESP, CP355, Araraquara, SP 14801-970 (Brazil); Ribeiro, Sidney J.L., E-mail: sidney@iq.unesp.br [Institute of Chemistry, São Paulo State University, UNESP, CP355, Araraquara, SP 14801-970 (Brazil)

    2016-02-15

    Nanostructured films prepared by Layer-by-Layer technique and containing silk fibroin, antigenic peptide NS5A-1 derived from hepatitis C virus (HCV) NS5A protein and YVO{sub 4}:Eu{sup 3+} luminescent nanoparticles, were utilized in sensing of hepatitis C. Detection system exploits the biorecognition between the antibody anti-HCV and the antigenic peptide NS5A-1 through changes in luminescence properties. Films deposition was monitored by UV–vis Absorption and Fluorescence Spectroscopy measurements at each bilayer deposited. The Eu{sup 3+} luminescence properties were evaluated in the presence of anti-HCV for optical detection of specific antibody and anti-HIV used as negative control. Significant changes in luminescence were observed in the presence of anti-HCV concentrations. A new immunosensor platform is proposed for optical detection of hepatitis C. - Highlights: • LbL films composed of silk fibroin, antigenic peptide NS5A-1 and YVO{sub 4}:Eu{sup 3+} NPs. • PL is sensitive to the presence of anti-HCV. • A new imunosensor platform is therefore proposed.

  2. Characterization of water in hydrated Bombyx mori silk fibroin fiber and films by 2H NMR relaxation and 13C solid state NMR.

    Science.gov (United States)

    Asakura, Tetsuo; Isobe, Kotaro; Kametani, Shunsuke; Ukpebor, Obehi T; Silverstein, Moshe C; Boutis, Gregory S

    2017-03-01

    The mechanical properties of Bombyx mori silk fibroin (SF), such as elasticity and tensile strength, change remarkably upon hydration. However, the microscopic interaction with water is not currently well understood on a molecular level. In this work, the dynamics of water molecules interacting with SF was studied by 2 H solution NMR relaxation and exchange measurements. Additionally, the conformations of hydrated [3- 13 C]Ala-, [3- 13 C]Ser-, and [3- 13 C]Tyr-SF fibers and films were investigated by 13 C DD/MAS NMR. Using an inverse Laplace transform algorithm, we were able to identify four distinct components in the relaxation times for water in SF fiber. Namely, A: bulk water outside the fiber, B: water molecules trapped weakly on the surface of the fiber, C: bound water molecules located in the inner surface of the fiber, and D: bound water molecules located in the inner part of the fiber were distinguishable. In addition, four components were also observed for water in the SF film immersed in methanol for 30s, while only two components for the film immersed in methanol for 24h. The effects of hydration on the conformation of Ser and Tyr residues in the site-specific crystalline and non-crystalline domains of 13 C selectively labeled SF, respectively, could be determined independently. Our measurements provide new insight relating the characteristics of water and the hydration structure of silk, which are relevant in light of current interest in the design of novel silk-based biomaterials. The mechanical properties of Bombyx mori silk fibroin (SF) change remarkably upon hydration. However, the microscopic interaction between SF and water is not currently well understood on a molecular level. We were able to identify four distinct components in the relaxation times for water in SF fiber by 2 H solution NMR relaxation and exchange measurements. In addition, the effects of hydration on the conformation of Ser and Tyr residues in the site-specific crystalline and

  3. 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)

  4. 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)

  5. Silver oxide nanoparticles embedded silk fibroin spuns: Microwave mediated preparation, characterization and their synergistic wound healing and anti-bacterial activity.

    Science.gov (United States)

    Babu, Punuri Jayasekhar; Doble, Mukesh; Raichur, Ashok M

    2018-03-01

    The synergistic wound healing and antibacterial activity of silver oxide nanoparticles embedded silk fibroin (Ag 2 O-SF) spuns is reported here. UV-Vis spectro photometric analysis of these spuns showed the surface plasmon resonance (SPR) confirming the formation of the silver oxide nanoparticles (Ag 2 O NPs) on the surface of the silk fibroin (SF). Scanning electron microscope (SEM) and Differential scanning calorimetry (DSC) also confirmed the presence of Ag 2 O NPs on surface of SF. X-ray diffraction (XRD) analysis revealed the crystalline nature of both SF and Ag 2 O-SF. Fourier transform infrared spectroscopy (FT-IR) results showed the different forms of silk (I and II) and their corresponding protein (amide I, II, III) confirmations. Biodegradation study revealed insignificant changes in the morphology of Ag 2 O-SF spuns even after 14 days of immersion in phosphate buffered saline (PBS). Ag 2 O-SF spuns showed excellent antibacterial activity against both pathogen (S. aureus and M. tuberculosis) and non-pathogen (E. coli) bacteria. More importantly, In vitro wound healing (scratch assay) assay revealed fast migration of the T3T fibroblast cells through the scratch area treated with extract of Ag 2 O-SF spuns and the area was completely covered within 24 h. Cytotoxicity assay confirmed the biocompatible nature of the Ag 2 O-SF spuns, thus suggesting an ideal material for wound healing and anti-bacterial applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. In vitro and in vivo studies on the cytotoxicity of irradiated silk fibroin against mouse melanoma tumor cell

    International Nuclear Information System (INIS)

    Byun, Eui-Baek; Sung, Nak-Yun; Kwon, Sun-Kyu; Song, Beom-Seok; Kim, Jae-Hun; Choi, Jong-il; Hwang, Han-Joon; Byun, Myung-Woo; Lee, Ju-Woon

    2009-01-01

    The physicochemical properties of proteins can be altered by irradiation. But, it is rarely that the researches on the functional properties of irradiated proteins have been reported. Fibroin is a fibrous protein derived from silkworm Bombyx mori and has been suggested as a biomaterial for biomedical application. Therefore, fibroin was selected as a model protein and was examined with the irradiation effects on the cytotoxicity of fibroin on tumor cell. The cytotoxicity of fibroin against mouse melanoma cell (B16BL6) showed a significant increase dependent upon the increase of irradiation dose. And also, the splenocyte proliferation activities of fibroin were increased by gamma irradiation. In addition, the oral administration of irradiated fibroin significantly increased the inhibition rate of tumor growth in tumor-bearing mouse model. The reason might be due to the change of protein structure by gamma irradiation and is being studied. From these result, it could be concluded that the irradiated fibroin might be a potential candidate as a valuable product in food and medical industry.

  7. In vitro and in vivo studies on the cytotoxicity of irradiated silk fibroin against mouse melanoma tumor cell

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Eui-Baek [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Division of Bioresources and Biosciences, Faculty of Agriculture, Graduate school of Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Sung, Nak-Yun [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Kwon, Sun-Kyu [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Graduate school of Food and Biotechnology, Korea University, Jochiwon 339-800 (Korea, Republic of); Song, Beom-Seok; Kim, Jae-Hun; Choi, Jong-il [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Hwang, Han-Joon [Graduate school of Food and Biotechnology, Korea University, Jochiwon 339-800 (Korea, Republic of); Byun, Myung-Woo [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Lee, Ju-Woon [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of)], E-mail: sjwlee@kaeri.re.kr

    2009-07-15

    The physicochemical properties of proteins can be altered by irradiation. But, it is rarely that the researches on the functional properties of irradiated proteins have been reported. Fibroin is a fibrous protein derived from silkworm Bombyx mori and has been suggested as a biomaterial for biomedical application. Therefore, fibroin was selected as a model protein and was examined with the irradiation effects on the cytotoxicity of fibroin on tumor cell. The cytotoxicity of fibroin against mouse melanoma cell (B16BL6) showed a significant increase dependent upon the increase of irradiation dose. And also, the splenocyte proliferation activities of fibroin were increased by gamma irradiation. In addition, the oral administration of irradiated fibroin significantly increased the inhibition rate of tumor growth in tumor-bearing mouse model. The reason might be due to the change of protein structure by gamma irradiation and is being studied. From these result, it could be concluded that the irradiated fibroin might be a potential candidate as a valuable product in food and medical industry.

  8. Conformations and Intermolecular Interactions in Cellulose/Silk Fibroin Blend Films: A Solid-State NMR Perspective.

    Science.gov (United States)

    Tian, Donglin; Li, Tao; Zhang, Rongchun; Wu, Qiang; Chen, Tiehong; Sun, Pingchuan; Ramamoorthy, Ayyalusamy

    2017-06-29

    Fabricating materials with excellent mechanical performance from the natural renewable and degradable biopolymers has drawn significant attention in recent decades due to the environmental concerns and energy crisis. As two of the most promising substitutes of synthetic polymers, silk fibroin (SF), and cellulose, have been widely used in the field of textile, biomedicine, biotechnology, etc. Particularly, the cellulose/SF blend film exhibits better strength and toughness than that of regenerated cellulose film. Herein, this study is aimed to understand the molecular origin of the enhanced mechanical properties for the cellulose/SF blend film, using solid-state NMR as a main tool to investigate the conformational changes, intermolecular interactions between cellulose and SF and the water organization. It is found that the content of the β-sheet structure is increased in the cellulose/SF blend film with respect to the regenerated SF film, accompanied by the reduction of the content of random coil structures. In addition, the strong hydrogen bonding interaction between the SF and cellulose is clearly elucidated by the two-dimensional (2D) 1 H- 13 C heteronuclear correlation (HETCOR) NMR experiments, demonstrating that the SF and cellulose are miscible at the molecular level. Moreover, it is also found that the -NH groups of SF prefer to form hydrogen bonds with the hydroxyl groups bonded to carbons C2 and C3 of cellulose, while the hydroxyl groups bonded to carbon C6 and the ether oxygen are less favorable for hydrogen bonding interactions with the -NH groups of SF. Interestingly, bound water is found to be present in the air-dried cellulose/SF blend film, which is predominantly associated with the cellulose backbones as determined by 2D 1 H- 13 C wide-line-separation (WISE) experiments with spin diffusion. This clearly reveals the presence of nanoheterogeneity in the cellulose/SF blend film, although cellulose and SF are miscible at a molecular level. Without doubt

  9. Physico-chemical properties and efficacy of silk fibroin fabric coated with different waxes as wound dressing.

    Science.gov (United States)

    Kanokpanont, Sorada; Damrongsakkul, Siriporn; Ratanavaraporn, Juthamas; Aramwit, Pornanong

    2013-04-01

    Silk fibroin (SF) has been widely used as a wound dressing material due to its suitable physical and biological characteristics. In this study, a non-adhesive wound dressing which applies to cover the wound surface as an absorbent pad that would absorb wound fluid while accelerate wound healing was developed. The modification of SF fabrics by wax coating was purposed to prepare the non-adhesive wound dressing that is required in order to minimize pain and risk of repeated injury. SF woven fabrics were coated with different types of waxes including shellac wax, beeswax, or carnauba wax. Physical and mechanical properties of the wax-coated SF fabrics were characterized. It was clearly observed that all waxes could be successfully coated on the SF fabrics, possibly due to the hydrophobic interactions between hydrophobic domains of SF and waxes. The wax coating improved tensile modulus and percentage of elongation of the SF fabrics due to the denser structure and the thicker fibers coated. The in vitro degradation study demonstrated that all wax-coated SF fabrics remained up to 90% of their original weights after 7 weeks of incubation in lysozyme solution under physiological conditions. The wax coating did not affect the degradation behavior of the SF fabrics. A peel test of the wax-coated SF fabrics was carried out in the partial- and full-thickness wounds of porcine skin in comparison to that of the commercial wound dressing. Any wax-coated SF fabrics were less adhesive than the control, as confirmed by less number of cells attached and less adhesive force. This might be that the wax-coated SF fabrics showed the hydrophobic property, allowing the loosely adherence to the hydrophilic wound surface. In addition, the in vivo biocompatibility test of the wax-coated SF fabrics was performed in Sprague-Dawley rats with subcutaneous model. The irritation scores indicated that the carnauba wax-coated SF fabric was not irritant while the shellac wax or beeswax-coated SF

  10. Investigation of silk fibroin nanoparticle-decorated poly(L-lactic acid composite scaffolds for osteoblast growth and differentiation

    Directory of Open Access Journals (Sweden)

    Chen BQ

    2017-03-01

    Full Text Available Biao-Qi Chen,1 Ranjith Kumar Kankala,1,2 Ai-Zheng Chen,1,2 Ding-Zhu Yang,1 Xiao-Xia Cheng,1 Ni-Na Jiang,1,2 Kai Zhu,3,4 Shi-Bin Wang1,2 1Institute of Biomaterials and Tissue Engineering, 2Fujian Provincial Key Laboratory of Biochemical Technology, Huaqiao University, Xiamen, Fujian, 3Department of Cardiac Surgery, Zhongshan Hospital, Fudan University, 4Shanghai Institute of Cardiovascular Disease, Shanghai, People’s Republic of China Abstract: Attempts to reflect the physiology of organs is quite an intricacy during the tissue engineering process. An ideal scaffold and its surface topography can address and manipulate the cell behavior during the regeneration of targeted tissue, affecting the cell growth and differentiation significantly. Herein, silk fibroin (SF nanoparticles were incorporated into poly(L-lactic acid (PLLA to prepare composite scaffolds via phase-inversion technique using supercritical carbon dioxide (SC-CO2. The SF nanoparticle core increased the surface roughness and hydrophilicity of the PLLA scaffolds, leading to a high affinity for albumin attachment. The in vitro cytotoxicity test of SF/PLLA scaffolds in L929 mouse fibroblast cells indicated good biocompatibility. Then, the in vitro interplay between mouse preosteoblast cell (MC3T3-E1 and various topological structures and biochemical cues were evaluated. The cell adhesion, proliferation, osteogenic differentiation and their relationship with the structures as well as SF content were explored. The SF/PLLA weight ratio (2:8 significantly affected the MC3T3-E1 cells by improving the expression of key players in the regulation of bone formation, ie, alkaline phosphatase (ALP, osteocalcin (OC and collagen 1 (COL-1. These results suggest not only the importance of surface topography and biochemical cues but also the potential of applying SF/PLLA composite scaffolds as biomaterials in bone tissue engineering. Keywords: super critical fluids, surface topography, bone

  11. Flow velocity-driven differentiation of human mesenchymal stromal cells in silk fibroin scaffolds: A combined experimental and computational approach.

    Directory of Open Access Journals (Sweden)

    Jolanda Rita Vetsch

    Full Text Available Mechanical loading plays a major role in bone remodeling and fracture healing. Mimicking the concept of mechanical loading of bone has been widely studied in bone tissue engineering by perfusion cultures. Nevertheless, there is still debate regarding the in-vitro mechanical stimulation regime. This study aims at investigating the effect of two different flow rates (vlow = 0.001m/s and vhigh = 0.061m/s on the growth of mineralized tissue produced by human mesenchymal stromal cells cultured on 3-D silk fibroin scaffolds. The flow rates applied were chosen to mimic the mechanical environment during early fracture healing or during bone remodeling, respectively. Scaffolds cultured under static conditions served as a control. Time-lapsed micro-computed tomography showed that mineralized extracellular matrix formation was completely inhibited at vlow compared to vhigh and the static group. Biochemical assays and histology confirmed these results and showed enhanced osteogenic differentiation at vhigh whereas the amount of DNA was increased at vlow. The biological response at vlow might correspond to the early stage of fracture healing, where cell proliferation and matrix production is prominent. Visual mapping of shear stresses, simulated by computational fluid dynamics, to 3-D micro-computed tomography data revealed that shear stresses up to 0.39mPa induced a higher DNA amount and shear stresses between 0.55mPa and 24mPa induced osteogenic differentiation. This study demonstrates the feasibility to drive cell behavior of human mesenchymal stromal cells by the flow velocity applied in agreement with mechanical loading mimicking early fracture healing (vlow or bone remodeling (vhigh. These results can be used in the future to tightly control the behavior of human mesenchymal stromal cells towards proliferation or differentiation. Additionally, the combination of experiment and simulation presented is a strong tool to link biological responses to

  12. Carbon fiber reinforced asphalt concrete

    International Nuclear Information System (INIS)

    Jahromi, Saeed G.

    2008-01-01

    Fibers are often used in the manufacture of other materials. For many years, they have been utilized extensively in numerous applications in civil engineering. Fiber-reinforcement refers to incorporating materials with desired properties within some other materials lacking those properties. Use of fibers is not a new phenomenon, as the technique of fiber-reinforced bitumen began early as 1950. In all industrialized countries today, nearly all concretes used in construction are reinforced. A multitude of fibers and fiber materials are being introduced in the market regularly. The present paper presents characteristics and properties of carbon fiber-reinforced asphalt mixtures, which improve the performance of pavements. To evaluate the effect of fiber contents on bituminous mixtures, laboratory investigations were carried out on the samples with and without fibers. During the course of this study, various tests were undertaken, applying Marshall Test indirect tensile test, creep test and resistance to fatigue cracking by using repeated load indirect tensile test. Carbon fiber exhibited consistency in results and as such it was observed that the addition of fiber does affect the properties of bituminous mixtures, i.e. an increase in its stability and decrease in the flow value as well as an increase in voids in the mix. Results indicate that fibers have the potential to resist structural distress in pavement, in the wake of growing traffic loads and thus improve fatigue by increasing resistance to cracks or permanent deformation. On the whole, the results show that the addition of carbon fiber will improve some of the mechanical properties like fatigue and deformation in the flexible pavement. (author)

  13. Silk-Fibroin and Graphene Oxide Composites Promote Human Periodontal Ligament Stem Cell Spontaneous Differentiation into Osteo/Cementoblast-Like Cells.

    Science.gov (United States)

    Vera-Sánchez, Mar; Aznar-Cervantes, Salvador; Jover, Eva; García-Bernal, David; Oñate-Sánchez, Ricardo E; Hernández-Romero, Diana; Moraleda, Jose M; Collado-González, Mar; Rodríguez-Lozano, Francisco Javier; Cenis, Jose Luis

    2016-11-15

    Graphene represents one of the most interesting additions to the tissue engineering toolbox. Novel graphene-based composites are required to improve the beneficial graphene properties in terms of tridimensional polymeric structure, conferring a higher mechanical strength and favoring the differentiation of human mesenchymal stem cells. Here, we have demonstrated in a wide range of composite combinations, the successful use of graphene and silk-fibroin constructs for future bioengineering applications in the field of clinical regenerative dentistry using human periodontal ligament stem cells. Our results provide exciting new data for the development of suitable scaffolds that allow good cell engrafting, preservation of cell viability and proliferation, promotion of spontaneous osteoblastic differentiation, and importantly, stimulation of a higher cementum physiological synthesis than using other different available biomaterials.

  14. Fabrication, characterization, and in vitro study of zinc substituted hydroxyapatite/silk fibroin composite coatings on titanium for biomedical applications.

    Science.gov (United States)

    Zhong, Zhenyu; Ma, Jun

    2017-09-01

    Zinc substituted hydroxyapatite/silk fibroin composite coatings were deposited on titanium substrates at room temperature by electrophoretic deposition. Microscopic characterization of the synthesized composite nanoparticles revealed that the particle size ranged 50-200 nm, which increased a little after zinc substitution. The obtained coatings maintained the phase of hydroxyapatite and they could induce fast apatite formation in simulated body fluid, indicating high bone activity. The cell culturing results showed that the biomimetic hydroxyapatite coatings could regulate adhesion, spreading, and proliferation of osteoblastic cells. Furthermore, the biological behavior of the zinc substituted hydroxyapatite coatings was found to be better than the bare titanium without coatings and hydroxyapatite coatings without zinc, increasing MC3T1-E1 cell differentiation in alkaline phosphatase expression.

  15. Potential applications of three-dimensional structure of silk fibroin/poly(ester-urethane) urea nanofibrous scaffold in heart valve tissue engineering

    Science.gov (United States)

    Du, Juan; Zhu, Tonghe; Yu, Haiyan; Zhu, Jingjing; Sun, Changbing; Wang, Jincheng; Chen, Sihao; Wang, Jihu; Guo, Xuran

    2018-07-01

    Tissue engineering heart valves (TEHV) are thought to have many advantages in low immunogenicity, good histocompatibility, excellent mechanical properties. In this paper, we reported the fabrication and characterization of a novel composite nanofibrous scaffold consisting of silk fibroin (SF) and poly(ester-urethane) urea (LDI-PEUU) by using electrospinning. Chemical and physical properties of scaffolds were evaluated using scanning electron microscopy, attenuated total reflectance Fourier transform infrared, X-ray diffraction, contact angle measurement, thermogravimetric analysis, biodegradation test and tensile strength analysis. We determined that the composite scaffolds supported the growth of human umbilical vein endothelial cell (HUVEC). The results of cell proliferation and cell morphology indicate that SF/LDI-PEUU nanofibers promoted cell viability, which supporting the application in tissue engineering. All results clarified that SF/LDI-PEUU (40:60) nanofibrous scaffolds meet the required specifications for tissue engineering and could be used as a promising construct for heart valve tissue engineering.

  16. Silk fibroin immobilization on poly(ethylene terephthalate) films: Comparison of two surface modification methods and their effect on mesenchymal stem cells culture

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Meini; Yao, Jinrong; Chen, Xin; Huang, Lei; Shao, Zhengzhong, E-mail: zzshao@fudan.edu.cn

    2013-04-01

    Silk fibroin (SF) has played a curial role for the surface modification of conventional materials to improve the biocompatibility, and SF modified poly(ethylene terephthalate) (PET) materials have potential applications on tissue engineering such as artificial ligament, artificial vessel, artificial heart valve sewing cuffs dacron and surgical mesh engineering. In this work, SF was immobilized onto PET film via two different methods: 1) plasma pretreatment followed by SF dip coating (PET-SF) and 2) plasma-induce acrylic acid graft polymerization and subsequent covalent immobilization of SF on PET film (PET-PAA-SF). It could be found that plasma treatment provided higher surface roughness which was suitable for further SF dip coating, while grafted poly(acrylic acid) (PAA) promised the covalent bonding between SF and PAA. ATR-FTIR adsorption band at 3284 cm{sup −1}, 1623 cm{sup −1} and 1520 cm{sup −1} suggested the successful introduction of SF onto PET surface, while the amount of immobilized SF of PET-SF was higher than PET-PAA-SF according to XPS investigation (0.29 vs 0.23 for N/C ratio). Surface modified PET film was used as substrate for mesenchymal stem cells (MSCs) culture, the cells on PET-SF surface exhibited optimum density compared to PET-PAA-SF according to CCK-8 assays, which indicated that plasma pretreatment followed by SF dip coating was a simple and effective way to prepare biocompatible PET surface. Highlights: ► Silk fibroins were immobilized onto PET films with or without the linker of PAA. ► Various techniques were performed to characterize the modified surfaces ► Plasma treatment followed by SF dip coating introduced more SF onto PET films. ► Compare to PET-PAA-SF, PET-SF has better biocompatibility base on MSCs culture.

  17. A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold 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); Henan provincial key laboratory of functional textile materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, 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); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); Han, Qiming [Henan provincial key laboratory of functional textile materials, 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 450000 (China); Wang, Qian [Henan provincial key laboratory of functional textile materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, 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); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); and others

    2016-10-01

    To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65 MPa and tensile strength 180.36 MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility. - Highlights: • A novel strategy to mimic the hierarchical collagen fibril in bone is proposed by electrospinning and conventional textile technology. • The tensile strength of the woven scaffold was nearly 4-fold larger than that of nonwoven mats. • The nanofiber woven scaffolds show excellent cytocompatibility and accelerate osteoblast differentiation. • The composite scaffold significantly enhanced formation of new bone in damaged condyles in rabbit femur.

  18. A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold for bone tissue engineering

    International Nuclear Information System (INIS)

    Shao, Weili; He, Jianxin; Han, Qiming; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong

    2016-01-01

    To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65 MPa and tensile strength 180.36 MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility. - Highlights: • A novel strategy to mimic the hierarchical collagen fibril in bone is proposed by electrospinning and conventional textile technology. • The tensile strength of the woven scaffold was nearly 4-fold larger than that of nonwoven mats. • The nanofiber woven scaffolds show excellent cytocompatibility and accelerate osteoblast differentiation. • The composite scaffold significantly enhanced formation of new bone in damaged condyles in rabbit femur.

  19. Luminous composite ultrathin films of CdTe quantum dots/silk fibroin co-assembled with layered doubled hydroxide: Enhanced photoluminescence and biosensor application

    Directory of Open Access Journals (Sweden)

    Muhammad Sohail Haroone

    2018-06-01

    Full Text Available Quantum dots (QDs luminescent films are extensively applied to optoelectronics and optical devices. However, QDs aggregation results in the quenching of their fluorescence property which limits their practical applications to a greater extent. In order to resolve this issue, 3-mercaptopropionic acid (3-MPA functionalized Cadmium Tellurium (CdTe QDs were stabilized by silk fibroin (SB and co-assembled with layered doubled hydroxide (LDH to form (QDs@SF/LDHn ultrathin films (UTFs via the layer-by-layer (LBL technique. UV–Vis absorption and fluorescence spectroscopy showed a stepwise and normal growth of the films upon increasing the number of deposition cycles. XRD and AFM studies confirmed the formation of a periodic layered structure and regular surface morphology of the thin films. As compared to (CdTe QDs/LDHnUTFs, the (CdTe QDs@SF/LDHnUTFs displayed fluorescence enhancement and longer fluorescent lifetime, both in solid states and aqueous solutions. Furthermore compared with the solution state, the fluorescence enhancement of SF-RC and SF-β are, respectively, 7 times and 17 times in the (CdTe QDs@SF/LDHn UTFs, indicating that the LDH nanosheets favor the fluorescence enhancement effect on the CdTe QDs@SF. The fabricated materials displayed fluorescence response to a biological molecule such as immune globulin, lgG. Thus, the (CdTe QDs@SF/LDHn UTFs has a potential to be used as biosensor. Keywords: CdTe quantum dots, Silk fibroin, Layered doubled hydroxide, Co-assembly, Fluorescence enhancement

  20. Silk fibroin nanoparticles constitute a vector for controlled release of resveratrol in an experimental model of inflammatory bowel disease in rats

    Directory of Open Access Journals (Sweden)

    Lozano-Pérez AA

    2014-09-01

    Full Text Available Antonio Abel Lozano-Pérez,1 Alba Rodriguez-Nogales,2 Víctor Ortiz-Cullera,1 Francesca Algieri,2 José Garrido-Mesa,2 Pedro Zorrilla,2 M Elena Rodriguez-Cabezas,2 Natividad Garrido-Mesa,2 M Pilar Utrilla,2 Laura De Matteis,3 Jesús Martínez de la Fuente,3 José Luis Cenis,1 Julio Gálvez2 1Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario, Murcia, Spain; 2Centro de Investigaciones Biomédicas en Red – Enfermedades Hepáticas y Digestivas, Department of Pharmacology, ibs Granada, Center for Biomedical Research, University of Granada, Granada, Spain; 3Instituto de Nanociencia de Aragón, Universidad de Zaragoza, Zaragoza, Spain Purpose: We aimed to evaluate the intestinal anti-inflammatory properties of silk fibroin nanoparticles, around 100 nm in size, when loaded with the stilbene compound resveratrol, in an experimental model of rat colitis. Methods: Nanoparticles were loaded with resveratrol by adsorption. The biological effects of the resveratrol-loaded nanoparticles were tested both in vitro, in a cell culture of RAW 264.7 cells (mouse macrophages, and in vivo, in the trinitrobenzenesulfonic acid model of rat colitis, when administered intracolonically.Results: The resveratrol liberation in 1× phosphate-buffered saline (PBS; pH 7.4 was characterized by fast liberation, reaching the solubility limit in 3 hours, which was maintained over a period of 80 hours. The in vitro assays revealed immunomodulatory properties exerted by these resveratrol-loaded nanoparticles since they promoted macrophage activity in basal conditions and inhibited this activity when stimulated with lipopolysaccharide. The in vivo experiments showed that after evaluation of the macroscopic symptoms, inflammatory markers, and intestinal barrier function, the fibroin nanoparticles loaded with resveratrol had a better effect than the single treatments, being similar to that produced by the glucocorticoid dexamethasone. Conclusion: Silk

  1. Enhancement of osseointegration of polyethylene terephthalate artificial ligament by coating of silk fibroin and depositing of hydroxyapatite

    Science.gov (United States)

    Jiang, Jia; Wan, Fang; Yang, Jianjun; Hao, Wei; Wang, Yaxian; Yao, Jinrong; Shao, Zhengzhong; Zhang, Peng; Chen, Jun; Zhou, Liang; Chen, Shiyi

    2014-01-01

    Background Application of artificial ligament in anterior cruciate ligament reconstruction is one of the research focuses of sports medicine but the biological tendon–bone healing still remains a problem. The preliminary study of hydroxyapatite (HAP) coating on the polyethylene terephthalate (PET) surface could effectively induce the osteoblast differentiation, but the tendon–bone healing was still not stable. As a green synthesis process, the biomimetic mineralization can simulate the natural bone growth in vitro and in vivo. Methods HAP crystals were grown under the guide of silk fibroin (SF) PET surface by biomimetic route. Several techniques including scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy were utilized for proving the introduction of both SF and HAP. The viability and osseointegration of bone marrow stromal cells on the surface of three kinds of ligament, including PET group (non-coating group), PET+SF group (SF-coating group), and PET+SF+HAP group (combined HAP- and SF-coating group), were analyzed by CCK-8 assays and alkaline phosphatase (ALP) detection. Seventy-two mature male New Zealand rabbits were randomly divided into three groups. Among them, 36 rabbits were sacrificed for mechanical testing, and histological examination for the others. Results The SF and SF+HAP were successfully coated on the surface of PET fiber. The CCK-8 assay showed that the cell proliferation on PET+SF+HAP group was better than the other two groups from 24 to 120 hours. After 14 days of culture, the cells in the PET+SF+HAP group delivered higher levels of ALP than the other two groups. After 3 days of culture, the expression level of integrin β1 in the PET+SF+HAP group and PET+SF group were higher than in the PET group. The mean load to failure and the stiffness value of the PET+SF+HAP group were both higher than the other two groups. Hematoxylin and

  2. Enhancement of osseointegration of polyethylene terephthalate artificial ligament by coating of silk fibroin and depositing of hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Jiang J

    2014-09-01

    Full Text Available Jia Jiang,1,2 Fang Wan,1 Jianjun Yang,1 Wei Hao,3 Yaxian Wang,3 Jinrong Yao,3 Zhengzhong Shao,3 Peng Zhang,1 Jun Chen,1 Liang Zhou,4 Shiyi Chen11Fudan University Sports Medicine Center and Department of Sports Medicine and Arthroscopy Surgery, Huashan Hospital, 2State Key Laboratory of Molecular Engineering of Polymers, 3Laboratory of Advanced Materials, National Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai, People’s Republic of China; 4Department of Forest Products, Anhui Agricultural University, Hefei Anhui Province, People’s Republic of ChinaBackground: Application of artificial ligament in anterior cruciate ligament reconstruction is one of the research focuses of sports medicine but the biological tendon–bone healing still remains a problem. The preliminary study of hydroxyapatite (HAP coating on the polyethylene terephthalate (PET surface could effectively induce the osteoblast differentiation, but the tendon–bone healing was still not stable. As a green synthesis process, the biomimetic mineralization can simulate the natural bone growth in vitro and in vivo.Methods: HAP crystals were grown under the guide of silk fibroin (SF PET surface by biomimetic route. Several techniques including scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy were utilized for proving the introduction of both SF and HAP. The viability and osseointegration of bone marrow stromal cells on the surface of three kinds of ligament, including PET group (non-coating group, PET+SF group (SF-coating group, and PET+SF+HAP group (combined HAP- and SF-coating group, were analyzed by CCK-8 assays and alkaline phosphatase (ALP detection. Seventy-two mature male New Zealand rabbits were randomly divided into three groups. Among them, 36 rabbits were sacrificed for mechanical testing, and

  3. Enhancement of osseointegration of polyethylene terephthalate artificial ligament by coating of silk fibroin and depositing of hydroxyapatite.

    Science.gov (United States)

    Jiang, Jia; Wan, Fang; Yang, Jianjun; Hao, Wei; Wang, Yaxian; Yao, Jinrong; Shao, Zhengzhong; Zhang, Peng; Chen, Jun; Zhou, Liang; Chen, Shiyi

    2014-01-01

    Application of artificial ligament in anterior cruciate ligament reconstruction is one of the research focuses of sports medicine but the biological tendon-bone healing still remains a problem. The preliminary study of hydroxyapatite (HAP) coating on the polyethylene terephthalate (PET) surface could effectively induce the osteoblast differentiation, but the tendon-bone healing was still not stable. As a green synthesis process, the biomimetic mineralization can simulate the natural bone growth in vitro and in vivo. HAP crystals were grown under the guide of silk fibroin (SF) PET surface by biomimetic route. Several techniques including scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy were utilized for proving the introduction of both SF and HAP. The viability and osseointegration of bone marrow stromal cells on the surface of three kinds of ligament, including PET group (non-coating group), PET+SF group (SF-coating group), and PET+SF+HAP group (combined HAP- and SF-coating group), were analyzed by CCK-8 assays and alkaline phosphatase (ALP) detection. Seventy-two mature male New Zealand rabbits were randomly divided into three groups. Among them, 36 rabbits were sacrificed for mechanical testing, and histological examination for the others. The SF and SF+HAP were successfully coated on the surface of PET fiber. The CCK-8 assay showed that the cell proliferation on PET+SF+HAP group was better than the other two groups from 24 to 120 hours. After 14 days of culture, the cells in the PET+SF+HAP group delivered higher levels of ALP than the other two groups. After 3 days of culture, the expression level of integrin β1 in the PET+SF+HAP group and PET+SF group were higher than in the PET group. The mean load to failure and the stiffness value of the PET+SF+HAP group were both higher than the other two groups. Hematoxylin and eosin staining showed that new bone

  4. Mechanics of fiber reinforced materials

    Science.gov (United States)

    Sun, Huiyu

    This dissertation is dedicated to mechanics of fiber reinforced materials and the woven reinforcement and composed of four parts of research: analytical characterization of the interfaces in laminated composites; micromechanics of braided composites; shear deformation, and Poisson's ratios of woven fabric reinforcements. A new approach to evaluate the mechanical characteristics of interfaces between composite laminae based on a modified laminate theory is proposed. By including an interface as a special lamina termed the "bonding-layer" in the analysis, the mechanical properties of the interfaces are obtained. A numerical illustration is given. For micro-mechanical properties of three-dimensionally braided composite materials, a new method via homogenization theory and incompatible multivariable FEM is developed. Results from the hybrid stress element approach compare more favorably with the experimental data than other existing numerical methods widely used. To evaluate the shearing properties for woven fabrics, a new mechanical model is proposed during the initial slip region. Analytical results show that this model provides better agreement with the experiments for both the initial shear modulus and the slipping angle than the existing models. Finally, another mechanical model for a woven fabric made of extensible yarns is employed to calculate the fabric Poisson's ratios. Theoretical results are compared with the available experimental data. A thorough examination on the influences of various mechanical properties of yarns and structural parameters of fabrics on the Poisson's ratios of a woven fabric is given at the end.

  5. Fiber reinforced polymer bridge decks : [technical summary].

    Science.gov (United States)

    2011-01-01

    A number of researchers have addressed the use of Fiber Reinforced Polymer (FRP) deck as a replacement solution for deteriorated bridge decks made of traditional materials. The use of new, advanced materials such as FRP is advantageous when the bridg...

  6. Surface modification of vascular endothelial growth factor-loaded silk fibroin to improve biological performance of ultra-high-molecular-weight polyethylene via promoting angiogenesis

    Directory of Open Access Journals (Sweden)

    Ai C

    2017-10-01

    Full Text Available Chengchong Ai, Dandan Sheng, Jun Chen, Jiangyu Cai, Siheng Wang, Jia Jiang, Shiyi Chen Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China Abstract: Ultra-high-molecular-weight polyethylene (UHMWPE has been applied in orthopedics, as the materials of joint prosthesis, artificial ligaments, and sutures due to its advantages such as high tensile strength, good wear resistance, and chemical stability. However, postoperative osteolysis induced by UHMWPE wear particles and poor bone–implant healing interface due to scarcity of osseointegration is a significant problem and should be solved imperatively. In order to enhance its affinity to bone tissue, vascular endothelial growth factor (VEGF was loaded on the surface of materials, the loading was performed by silk fibroin (SF coating to achieve a controlled-release delivery. Several techniques including field emission scanning electron microscopy (FESEM and attenuated total reflectance (ATR-Fourier transform infrared (FTIR and water contact angle measurement were used to validate the effectiveness of introduction of SF/VEGF. The result of ELISA demonstrated that the release of VEGF was well maintained up to 4 weeks. The modified UHMWPE was evaluated by both in vitro and in vivo experiments. According to the results of FESEM and cell counting kit-8 (CCK-8 assay, bone marrow mesenchymal stem cells cultured on the UHMWPE coated with SF/VEGF and SF exhibited a better proliferation performance than that of the pristine UHMWPE. The model rabbit of anterior cruciate ligament reconstruction was used to observe the graft–bone healing process in vivo. The results of histological evaluation, microcomputed tomography (micro-CT analysis, and biomechanical tests performed at 6 and 12 weeks after surgery demonstrated that graft–bone healing could be significantly improved due to the effect of VEGF on angiogenesis, which was loaded on the surface by SF

  7. 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.

  8. A novel chitosan-tussah silk fibroin/nano-hydroxyapatite composite bone scaffold platform with tunable mechanical strength in a wide range.

    Science.gov (United States)

    Ran, Jiabing; Hu, Jingxiao; Sun, Guanglin; Chen, Si; Jiang, Pei; Shen, Xinyu; Tong, Hua

    2016-12-01

    Currently, great efforts have been made to enhance the mechanical strength of bone tissue engineering (BTE) scaffolds, which are composed of biopolymeric matrices and inorganic nano-fillers. But the tunability of mechanical strength in a wide range for BTE scaffolds has seldom been investigated in spite of the great importance of this performance. In this work, a chitosan-tussah silk fibroin/hydroxyapatite (CS-TSF/HAp) hydrogel was synthesized by using a novel in situ precipitation method. Through in situ inducing the conformation transition of TSF in the CS-TSF/HAp hydrogel, which could be monitored by XRD, FT-IR, TGA, and DTA, the elastic modulus and fracture strength of the final CS-TSF/HAp composite could be tailored in a wide range without changing its composition, morphology, roughness, and crystal structures. The elastic modulus of the CS-TSF/HAp composite ranged from ∼250 to ∼400MPa while its fracture strength ranged from ∼45 to ∼100MPa. In order to clarify the rationale behind this process, a speculative explanation was provided. In vitro cell culture indicated that MC3T3-E1 cells cultured on the CS-TSF/HAp composite had positive adhesion, proliferation, and differentiation potential. We believed that the CS-TSF/HAp composite could be used as an ideal scaffold platform for cell culture and implantation of bone reconstruction. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. 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.

  10. Starch nanoparticle as a vitamin E-TPGS carrier loaded in silk fibroin-poly(vinyl alcohol)-Aloe vera nanofibrous dressing.

    Science.gov (United States)

    Kheradvar, Shadi Alsadat; Nourmohammadi, Jhamak; Tabesh, Hadi; Bagheri, Behnam

    2018-06-01

    Core-sheath nanofibrous mat as a new vitamin E (VE) delivery system based on silk fibroin (SF)/poly(vinyl alcohol) (PVA)/aloe vera (AV) was successfully prepared by the electrospinning method. Initially, VE-loaded starch nanoparticles were produced and then incorporated into the best beadless SF-PVA-AV nanofibers. The successful loading of VE in starch nanoparticles was proved by Fourier-transform infrared spectroscopy. The scanning electron microscopy and transmission electron microscopy indicated that spherical nanoparticles were successfully embedded within the nanofibers. In vitro release studies demonstrated that the release of VE was controlled by Fickian diffusion and was faster in samples containing more nanoparticles. Fibroblast attachment, proliferation, and collagen secretion were enhanced after adding AV and VE to the SF-PVA nanomatrix. Moreover, the incorporation of VE into the nanocomposite dressing enhanced antioxidant activity, which can have a positive effect on wound healing process by protecting the cells from toxic oxidation products. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Surface modification of strontium-doped porous bioactive ceramic scaffolds via poly(DOPA) coating and immobilizing silk fibroin for excellent angiogenic and osteogenic properties.

    Science.gov (United States)

    Wang, Xu; Gu, Zhipeng; Jiang, Bo; Li, Li; Yu, Xixun

    2016-04-01

    For bioceramic scaffolds employed in clinical applications, excellent bioactivity and tenacity were of great importance. Modifying inorganic SCPP scaffolds with biological macromolecules could obviously improve its bioactivity and eliminate its palpable brittleness. However, it was hard to execute directly due to extremely bad interfacial compatibility between them. In this research, dopamine (DOPA) was introduced onto strontium-doped calcium polyphosphate (SCPP) scaffolds, subsequently the preliminary material was successfully further modified by silk fibroin (SF). SCPP/D/SF possessed suitable biomechanical properties, ability to stimulate angiogenic factor secretion and excellent biocompatibility. Biomechanical examination demonstrated that SCPP/D/SF scaffolds yielded better compressive strength because of improved interfacial compatibility. MTT assay and CLSM observation showed that SCPP/D/SF scaffolds had good cytocompatibility and presented better inducing-cell-migration potential than pure SCPP scaffolds. Meanwhile, its ability to stimulate angiogenic factor secretion was measured through the ELISA assay and immunohistological analysis in vitro and in vivo respectively. The results revealed, superior to SCPP, SCPP/D/SF could effectively promote VEGF and bFGF expression, possibly leading to enhancing angiogenesis and osteogenesis. In a word, SCPP/D/SF could serve as a potential bone tissue engineering scaffold for comparable biomechanical properties and excellent bioactivity. It provided a novel idea for modification of inorganic materials to prepare promising bone tissue engineering scaffolds with the ability to accelerate bone regeneration and vascularization.

  12. From 2D to 3D: The morphology, proliferation and differentiation of MC3T3-E1 on silk fibroin/chitosan matrices.

    Science.gov (United States)

    Li, Da-Wei; He, Feng-Li; He, Jin; Deng, Xudong; Liu, Ya-Li; Liu, Yang-Yang; Ye, Ya-Jing; Yin, Da-Chuan

    2017-12-15

    It has been widely accepted that cell culture in two-dimensional (2D) conditions may not be able to represent growth in three-dimensional (3D) conditions. Systematic comparisons between 2D and 3D cell cultures are needed to appropriately use the existing 2D results. In this work, we conducted a comparative study between 2D and 3D cell cultures of MC3T3-E1 using the same type of material (a mixture of silk fibroin (SF) and chitosan (CS)). Our results showed 3D SF/CS scaffold exhibited different effects on cell culture compared with the 2D cases. 1) The cells grown in 3D scaffold showed multiple morphologies. 2) The proliferation of cells in 3D scaffold was long-term and sustainable. 3) Cell differentiation occurred throughout the entire 3D scaffold. The results showed that cell culture in 3D SF/CS scaffold exhibited different features than 2D cases and 3D SF/CS scaffold could be a promising material for 3D cell culture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. In vitro cartilage construct generation from silk fibroin- chitosan porous scaffold and umbilical cord blood derived human mesenchymal stem cells in dynamic culture condition.

    Science.gov (United States)

    Agrawal, Parinita; Pramanik, Krishna; Biswas, Amit; Ku Patra, Ranjan

    2018-02-01

    Cartilage construct generation includes a scaffold with appropriate composition to mimic matrix of the damaged tissue on which the stem cells grow and differentiate. In this study, umbilical cord blood (UCB) derived human mesenchymal stem cells (hMSCs) were seeded on freeze dried porous silk-fibroin (SF)/chitosan (CS) scaffolds. Influence of static and dynamic (spinner flask bioreactor) culture conditions on the developing cartilage construct were studied by in-vitro characterization for viability, proliferation, distribution, and chondrogenic differentiation of hMSCs over the scaffold. Constructs developed in spinner flask consisted of 62% live cells, and exhibited 543% more cell density at the core than constructs cultured in static system. Quantification of DNA and glycosaminoglycans accumulation after 21 days showed the progression of chondrogenic differentiation of hMSCs was higher in dynamic culture compared to static one. In constructs generated under dynamic condition, histology staining for proteoglycan matrix, and fluorescence staining for collagen-II and aggrecan showed positive correlation between early and late stage chondrogenic markers, which was further confirmed by quantitative PCR analysis, showing low collagen-I expression and highly expressed Sox9, collagen-II and aggrecan. The present study demonstrated that construct generated by combining 3D SF/CS scaffold with UCB-hMSCs under dynamic condition using spinner flask bioreactor can be used for cartilage tissue regeneration for future medical treatments. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 397-407, 2018. © 2017 Wiley Periodicals, Inc.

  14. Silk fibroin/chitosan scaffold with tunable properties and low inflammatory response assists the differentiation of bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Li, Da-Wei; Lei, Xiaohua; He, Feng-Li; He, Jin; Liu, Ya-Li; Ye, Ya-Jing; Deng, Xudong; Duan, Enkui; Yin, Da-Chuan

    2017-12-01

    The physical and chemical properties of the scaffold are known to play important roles in three-dimensional (3D) cell culture, which always determine the cellular fate or the results of implantation. To control these properties becomes necessary for meeting the requirements of a variety of tissue engineering applications. In this study, a series of silk fibroin/chitosan (SF/CS) scaffolds with tunable properties were prepared using freeze-drying method, and the rat bone marrow-derived mesenchymal stem cells (BM-MSCs) were seeded in these scaffolds to evaluate their availability of use in tissue engineering. The 3D structure, mechanical properties and degradation ability of SF/CS scaffold can be tuned by changing the total concentration of the precursor solution and the blending ratio between SF and CS. BM-MSCs cultured in the SF/CS scaffold exhibited excellent proliferation and multiple morphologies. The induction of osteogenic and adipogenic differentiation of BM-MSCs were successful in this scaffold when cultured in vitro. Subcutaneous implantation of the SF/CS scaffolds did not cause any inflammatory response within four weeks, which revealed good compatibility. Moreover, the implanted scaffold allowed host cells to invade, adhere, grow and form new blood vessels. With these excellent performance, SF/CS scaffold has great potential in preparing implants for tissue engineering applications. Copyright © 2017. Published by Elsevier B.V.

  15. The usage of carbon fiber reinforcement polymer and glass fiber reinforcement polymer for retrofit technology building

    Science.gov (United States)

    Tarigan, Johannes; Meka, Randi; Nursyamsi

    2018-03-01

    Fiber Reinforcement Polymer has been used as a material technology since the 1970s in Europe. Fiber Reinforcement Polymer can reinforce the structure externally, and used in many types of buildings like beams, columns, and slabs. It has high tensile strength. Fiber Reinforcement Polymer also has high rigidity and strength. The profile of Fiber Reinforcement Polymer is thin and light, installation is simple to conduct. One of Fiber Reinforcement Polymer material is Carbon Fiber Reinforcement Polymer and Glass Fiber Reinforcement Polymer. These materials is tested when it is installed on concrete cylinders, to obtain the comparison of compressive strength CFRP and GFRP. The dimension of concrete is diameter of 15 cm and height of 30 cm. It is amounted to 15 and divided into three groups. The test is performed until it collapsed to obtain maximum load. The results of research using CFRP and GFRP have shown the significant enhancement in compressive strength. CFRP can increase the compressive strength of 26.89%, and GFRP of 14.89%. For the comparison of two materials, CFRP is more strengthening than GFRP regarding increasing compressive strength. The usage of CFRP and GFRP can increase the loading capacity.

  16. Fatigue Performance of Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Jun, Zhang; Stang, Henrik

    1996-01-01

    The objective of the present study is to obtain basic data of fibre reinforced concrete under fatigue load and to set up a theoretical model based on micromechanics. In this study, the bridging stress in fiber reinforced concrete under cyclic tensile load was investigted in details. The damage...... mechanism of the interface between fiber and matrix was proposed and a rational model given. Finally, the response of a steel fiber reinforced concrete beam under fatigue loading was predicted based on this model and compared with experimental results....

  17. Influence of the mechanical environment on the engineering of mineralised tissues using human dental pulp stem cells and silk fibroin scaffolds.

    Directory of Open Access Journals (Sweden)

    Anna Woloszyk

    Full Text Available Teeth constitute a promising source of stem cells that can be used for tissue engineering and regenerative medicine purposes. Bone loss in the craniofacial complex due to pathological conditions and severe injuries could be treated with new materials combined with human dental pulp stem cells (hDPSCs that have the same embryonic origin as craniofacial bones. Optimising combinations of scaffolds, cells, growth factors and culture conditions still remains a great challenge. In the present study, we evaluate the mineralisation potential of hDPSCs seeded on porous silk fibroin scaffolds in a mechanically dynamic environment provided by spinner flask bioreactors. Cell-seeded scaffolds were cultured in either standard or osteogenic media in both static and dynamic conditions for 47 days. Histological analysis and micro-computed tomography of the samples showed low levels of mineralisation when samples were cultured in static conditions (0.16±0.1 BV/TV%, while their culture in a dynamic environment with osteogenic medium and weekly µCT scans (4.9±1.6 BV/TV% significantly increased the formation of homogeneously mineralised structures, which was also confirmed by the elevated calcium levels (4.5±1.0 vs. 8.8±1.7 mg/mL. Molecular analysis of the samples showed that the expression of tooth correlated genes such as Dentin Sialophosphoprotein and Nestin were downregulated by a factor of 6.7 and 7.4, respectively, in hDPSCs when cultured in presence of osteogenic medium. This finding indicates that hDPSCs are able to adopt a non-dental identity by changing the culture conditions only. Also an increased expression of Osteocalcin (1.4x and Collagen type I (1.7x was found after culture under mechanically dynamic conditions in control medium. In conclusion, the combination of hDPSCs and silk scaffolds cultured under mechanical loading in spinner flask bioreactors could offer a novel and promising approach for bone tissue engineering where appropriate and

  18. Influence of the mechanical environment on the engineering of mineralised tissues using human dental pulp stem cells and silk fibroin scaffolds.

    Science.gov (United States)

    Woloszyk, Anna; Holsten Dircksen, Sabrina; Bostanci, Nagihan; Müller, Ralph; Hofmann, Sandra; Mitsiadis, Thimios A

    2014-01-01

    Teeth constitute a promising source of stem cells that can be used for tissue engineering and regenerative medicine purposes. Bone loss in the craniofacial complex due to pathological conditions and severe injuries could be treated with new materials combined with human dental pulp stem cells (hDPSCs) that have the same embryonic origin as craniofacial bones. Optimising combinations of scaffolds, cells, growth factors and culture conditions still remains a great challenge. In the present study, we evaluate the mineralisation potential of hDPSCs seeded on porous silk fibroin scaffolds in a mechanically dynamic environment provided by spinner flask bioreactors. Cell-seeded scaffolds were cultured in either standard or osteogenic media in both static and dynamic conditions for 47 days. Histological analysis and micro-computed tomography of the samples showed low levels of mineralisation when samples were cultured in static conditions (0.16±0.1 BV/TV%), while their culture in a dynamic environment with osteogenic medium and weekly µCT scans (4.9±1.6 BV/TV%) significantly increased the formation of homogeneously mineralised structures, which was also confirmed by the elevated calcium levels (4.5±1.0 vs. 8.8±1.7 mg/mL). Molecular analysis of the samples showed that the expression of tooth correlated genes such as Dentin Sialophosphoprotein and Nestin were downregulated by a factor of 6.7 and 7.4, respectively, in hDPSCs when cultured in presence of osteogenic medium. This finding indicates that hDPSCs are able to adopt a non-dental identity by changing the culture conditions only. Also an increased expression of Osteocalcin (1.4x) and Collagen type I (1.7x) was found after culture under mechanically dynamic conditions in control medium. In conclusion, the combination of hDPSCs and silk scaffolds cultured under mechanical loading in spinner flask bioreactors could offer a novel and promising approach for bone tissue engineering where appropriate and rapid bone

  19. Transplantation of human placenta-derived mesenchymal stem cells in a silk fibroin/hydroxyapatite scaffold improves bone repair in rabbits.

    Science.gov (United States)

    Jin, Jun; Wang, Jun; Huang, Jian; Huang, Fang; Fu, Jianhong; Yang, Xinjing; Miao, Zongning

    2014-11-01

    The main requirements for successful tissue engineering of the bone are non-immunogenic cells with osteogenic potential and a porous biodegradable scaffold. The purpose of this study is to evaluate the potential of a silk fibroin/hydroxyapatite (SF/HA) porous material as a delivery vehicle for human placenta-derived mesenchymal stem cells (PMSCs) in a rabbit radius defect model. In this study, we randomly assigned 16 healthy adult New Zealand rabbits into two groups, subjected to transplantation with either SF/HA and PMSCs (experimental group) or SF/HA alone (control group). To evaluate fracture healing, we assessed the extent of graft absorption, the quantity of newly formed bone, and re-canalization of the cavitas medullaris using radiographic and histological tools. We performed flow cytometric analysis to characterize PMSCs, and found that while they express CD90, CD105 and CD73, they stain negative for HLA-DR and the hematopoietic cell surface markers CD34 and CD45. When PMSCs were exposed to osteogenic induction medium, they secreted calcium crystals that were identified by von Kossa staining. Furthermore, when seeded on the surface of SF/HA scaffold, they actively secreted extracellular matrix components. Here, we show, through radiographic and histological analyses, that fracture healing in the experimental group is significantly improved over the control group. This strongly suggests that transplantation of human PMSCs grown in an SF/HA scaffold into injured radius segmental bone in rabbits, can markedly enhance tissue repair. Our finding provides evidence supporting the utility of human placenta as a potential source of stem cells for bone tissue engineering. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  20. 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.

  1. Heparin functionalization increases retention of TGF-β2 and GDF5 on biphasic silk fibroin scaffolds for tendon/ligament-to-bone tissue engineering.

    Science.gov (United States)

    Font Tellado, Sònia; Chiera, Silvia; Bonani, Walter; Poh, Patrina S P; Migliaresi, Claudio; Motta, Antonella; Balmayor, Elizabeth R; van Griensven, Martijn

    2018-05-01

    The tendon/ligament-to-bone transition (enthesis) is a highly specialized interphase tissue with structural gradients of extracellular matrix composition, collagen molecule alignment and mineralization. These structural features are essential for enthesis function, but are often not regenerated after injury. Tissue engineering is a promising strategy for enthesis repair. Engineering of complex tissue interphases such as the enthesis is likely to require a combination of biophysical, biological and chemical cues to achieve functional tissue regeneration. In this study, we cultured human primary adipose-derived mesenchymal stem cells (AdMCs) on biphasic silk fibroin scaffolds with integrated anisotropic (tendon/ligament-like) and isotropic (bone/cartilage like) pore alignment. We functionalized those scaffolds with heparin and explored their ability to deliver transforming growth factor β2 (TGF-β2) and growth/differentiation factor 5 (GDF5). Heparin functionalization increased the amount of TGF-β2 and GDF5 remaining attached to the scaffold matrix and resulted in biological effects at low growth factor doses. We analyzed the combined impact of pore alignment and growth factors on AdMSCs. TGF-β2 and pore anisotropy synergistically increased the expression of tendon/ligament markers and collagen I protein content. In addition, the combined delivery of TGF-β2 and GDF5 enhanced the expression of cartilage markers and collagen II protein content on substrates with isotropic porosity, whereas enthesis markers were enhanced in areas of mixed anisotropic/isotropic porosity. Altogether, the data obtained in this study improves current understanding on the combined effects of biological and structural cues on stem cell fate and presents a promising strategy for tendon/ligament-to-bone regeneration. Regeneration of the tendon/ligament-to-bone interphase (enthesis) is of significance in the repair of ruptured tendons/ligaments to bone to improve implant integration and

  2. A β-cyclodextrin, polyethyleneimine and silk fibroin hydrogel containing Centella asiatica extract and hydrocortisone acetate: releasing properties and in vivo efficacy for healing of pressure sores.

    Science.gov (United States)

    Lee, M S; Seo, S R; Kim, J-C

    2012-10-01

      Pressure sores are lesions caused by impaired blood flow. Conventional dressings can absorb exudates, but do not promote wound healing. A hydrogel composed of β-cyclodextrin (β-CD), polyethyleneimine (PEI) and silk fibroin (SF) was assessed for use in healing of pressure sores. The hydrogel was prepared by crosslinking β-CD-grafted PEI and SF using epichlorohydrin. The gel was then immersed in an aqueous solution of Centella asiatica extract (CAE) 0.7 mg/mL and/or hydrocortisone acetate (HCA) 0.5 mg/mL. The in vivo pressure sore-healing efficacy of the dry gel (with or without the drugs) was investigated in terms of the hyperplasia of epidermis and the number of neutrophils in the skin tissue. The specific loading of CAE was 0.0091 g/g of dry gel. The percentage of CAE released at 24 h at pH 3.0, 5.0 and 7.4 was approximately 63.9%, 55.0% and 44.4%, respectively. This pH-dependent release is possibly due to the degree of gel swelling, which decreased with increasing pH. The specific loading of HCA was 0.0050 g/g dry gel, and the percentage release of HCA at 24 h was around 20% at all three pH points. It is likely that HCA release is independent of pH. HCA is a hydrophobic compound, and therefore the release of HCA is affected by the partitioning of HCA between the β-CD cavity and the bulk water phase, but not by the degree of swelling of the hydrogel. The pressure sores treated with the hydrogel healed in 6 days, compared with 10 days for controls. In this study, a β-CD/PEI/SF hydrogel containing CAE and HCA reduced the healing time for pressure sores. © The Author(s). CED © 2012 British Association of Dermatologists.

  3. Effect of hybrid fiber reinforcement on the cracking process in fiber reinforced cementitious composites

    DEFF Research Database (Denmark)

    Pereira, Eduardo B.; Fischer, Gregor; Barros, Joaquim A.O.

    2012-01-01

    The simultaneous use of different types of fibers as reinforcement in cementitious matrix composites is typically motivated by the underlying principle of a multi-scale nature of the cracking processes in fiber reinforced cementitious composites. It has been hypothesized that while undergoing...... tensile deformations in the composite, the fibers with different geometrical and mechanical properties restrain the propagation and further development of cracking at different scales from the micro- to the macro-scale. The optimized design of the fiber reinforcing systems requires the objective...... materials is carried out by assessing directly their tensile stress-crack opening behavior. The efficiency of hybrid fiber reinforcements and the multi-scale nature of cracking processes are discussed based on the experimental results obtained, as well as the micro-mechanisms underlying the contribution...

  4. Structure determination of a peptide model of the repeated helical domain in Samia cynthia ricini silk fibroin before spinning by a combination of advanced solid-state NMR methods.

    Science.gov (United States)

    Nakazawa, Yasumoto; Asakura, Tetsuo

    2003-06-18

    Fibrous proteins unlike globular proteins, contain repetitive amino acid sequences, giving rise to very regular secondary protein structures. Silk fibroin from a wild silkworm, Samia cynthia ricini, consists of about 100 repeats of alternating polyalanine (poly-Ala) regions of 12-13 residues in length and Gly-rich regions. In this paper, the precise structure of the model peptide, GGAGGGYGGDGG(A)(12)GGAGDGYGAG, which is a typical repeated sequence of the silk fibroin, was determined using a combination of three kinds of solid-state NMR studies; a quantitative use of (13)C CP/MAS NMR chemical shift with conformation-dependent (13)C chemical shift contour plots, 2D spin diffusion (13)C solid-state NMR under off magic angle spinning and rotational echo double resonance. The structure of the model peptide corresponding to the silk fibroin structure before spinning was determined. The torsion angles of the central Ala residue, Ala(19), in the poly-Ala region were determined to be (phi, psi) = (-59 degrees, -48 degrees ) which are values typically associated with alpha-helical structures. However, the torsion angles of the Gly(25) residue adjacent to the C-terminal side of the poly-Ala chain were determined to be (phi, psi) = (-66 degrees, -22 degrees ) and those of Gly(12) and Ala(13) residues at the N-terminal of the poly-Ala chain to be (phi, psi) = (-70 degrees, -30 degrees ). In addition, REDOR experiments indicate that the torsion angles of the two C-terminal Ala residues, Ala(23) and Ala(24), are (phi, psi) = (-66 degrees, -22 degrees ) and those of N-terminal two Ala residues, Ala(13) and Ala(14) are (phi, psi) = (-70 degrees, -30 degrees ). Thus, the local structure of N-terminal and C-terminal residues, and also the neighboring residues of alpha-helical poly-Ala chain in the model peptide is a more strongly wound structure than found in typical alpha-helix structures.

  5. FLEXURAL TOUGHNESS OF STEEL FIBER REINFORCED CONCRETE

    Directory of Open Access Journals (Sweden)

    Fehmi ÇİVİCİ

    2006-02-01

    Full Text Available Fiber concrete is a composite material which has mechanical and physical characteristics unlike plain concrete. One of the important mechanical characteristics of fiber concrete is its energy absorbing capability. This characteristics which is also called toughness, is defined as the total area under the load-deflection curve. A number of composite characteristics such as crack resistance, ductility and impact resistance are related to the energy absorbtion capacity. According to ASTM C 1018 and JSCE SF-4 the calculation of toughness is determined by uniaxial flexural testing. Fiber concrete is often used in plates such as bridge decks, airport pavements, parking areas, subjected to cavitation and erosion. In this paper, toughness has been determined according to ASTM C 1018 and JSCE SF-4 methods by testing beam specimens. Energy absorbing capacities of plain and steel fiber reinforced concrete has been compared by evaluating the results of two methods. Also plain and steel fiber reinforced plate specimens behaviors subjected to biaxial flexure are compared by the loaddeflection curves of each specimen.

  6. 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.

  7. On the simulation of kink bands in fiber reinforced composites

    DEFF Research Database (Denmark)

    Sørensen, K.D.; Mikkelsen, Lars Pilgaard; Jensen, H.M.

    2007-01-01

    Simulations of kink band formation in fiber reinforced composites are carried out using the commercial finite element program ABAQUS. A smeared-out, plane constitutive model for fiber reinforced materials is implemented as a user subroutine, and effects of fiber misalignment on elastic and plastic...

  8. Cohesive fracture model for functionally graded fiber reinforced concrete

    International Nuclear Information System (INIS)

    Park, Kyoungsoo; Paulino, Glaucio H.; Roesler, Jeffery

    2010-01-01

    A simple, effective, and practical constitutive model for cohesive fracture of fiber reinforced concrete is proposed by differentiating the aggregate bridging zone and the fiber bridging zone. The aggregate bridging zone is related to the total fracture energy of plain concrete, while the fiber bridging zone is associated with the difference between the total fracture energy of fiber reinforced concrete and the total fracture energy of plain concrete. The cohesive fracture model is defined by experimental fracture parameters, which are obtained through three-point bending and split tensile tests. As expected, the model describes fracture behavior of plain concrete beams. In addition, it predicts the fracture behavior of either fiber reinforced concrete beams or a combination of plain and fiber reinforced concrete functionally layered in a single beam specimen. The validated model is also applied to investigate continuously, functionally graded fiber reinforced concrete composites.

  9. Micromechanical failure in fiber-reinforced composites

    DEFF Research Database (Denmark)

    Ashouri Vajari, Danial

    Micromechanical failure mechanisms occurring in unidirectional fiber-reinforced composites are studied by means of the finite element method as well as experimental testing. This study highlights the effect of micro-scale features such as fiber/matrix interfacial debonding, matrix cracking...... and microvoids on the microscopic and macroscopic mechanical response of composite materials. To this end, first a numerical study is carried out to explore ways to stabilize interfacial crack growth under dominant Mode-I fracture using the cohesive zone model. Consequently, this study suggests a method...... composites. In the first approach, the J2 plasticity model is implemented to model the elasto-plastic behavior of the matrix while in the second strategy the modified Drucker-Prager plasticity model is utilized to account for brittle-like and pressure dependent behavior of an epoxy matrix. In addition...

  10. [Fusion implants of carbon fiber reinforced plastic].

    Science.gov (United States)

    Früh, H J; Liebetrau, A; Bertagnoli, R

    2002-05-01

    Carbon fiber reinforced plastics (CFRP) are used in the medical field when high mechanical strength, innovative design, and radiolucency (see spinal fusion implants) are needed. During the manufacturing process of the material CFRP carbon fibers are embedded into a resin matrix. This resin material could be thermoset (e.g., epoxy resin EPN/DDS) or thermoplastic (e.g., PEAK). CFRP is biocompatible, radiolucent, and has higher mechanical capabilities compared to other implant materials. This publication demonstrates the manufacturing process of fusion implants made of a thermoset matrix system using a fiber winding process. The material has been used clinically since 1994 for fusion implants of the cervical and lumbar spine. The results of the fusion systems CORNERSTONE-SR C (cervical) and UNION (lumbar) showed no implant-related complications. New implant systems made of this CFRP material are under investigation and are presented.

  11. 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.

  12. CODIFICATION OF FIBER REINFORCED COMPOSITE PIPING

    Energy Technology Data Exchange (ETDEWEB)

    Rawls, G.

    2012-10-10

    The goal of the overall project is to successfully adapt spoolable FRP currently used in the oil industry for use in hydrogen pipelines. The use of FRP materials for hydrogen service will rely on the demonstrated compatibility of these materials for pipeline service environments and operating conditions. The ability of the polymer piping to withstand degradation while in service, and development of the tools and data required for life management are imperative for successful implementation of these materials for hydrogen pipeline. The information and data provided in this report provides the technical basis for the codification for fiber reinforced piping (FRP) for hydrogen service. The DOE has invested in the evaluation of FRP for the delivery for gaseous hydrogen to support the development of a hydrogen infrastructure. The codification plan calls for detailed investigation of the following areas: System design and applicable codes and standards; Service degradation of FRP; Flaw tolerance and flaw detection; Integrity management plan; Leak detection and operational controls evaluation; Repair evaluation. The FRP codification process started with commercially available products that had extensive use in the oil and gas industry. These products have been evaluated to assure that sufficient structural integrity is available for a gaseous hydrogen environment.

  13. Natural fiber-reinforced polymer composites

    International Nuclear Information System (INIS)

    Taj, S.; Khan, S.; Munawar, M.A.

    2007-01-01

    Natural fibers have been used to reinforce materials for over 3,000 years. More recently they have been employed in combination with plastics. Many types of natural fi fibers have been investigated for use in plastics including Flax, hemp, jute, straw, wood fiber, rice husks, wheat, barley, oats, rye, cane (sugar and bamboo), grass reeds, kenaf, ramie, oil palm empty fruit bunch, sisal, coir, water hyacinth, pennywort, kapok, paper-mulberry, raphia, banana fiber, pineapple leaf fiber and papyrus. Natural fibers have the advantage that they are renewable resources and have marketing appeal. The Asian markets have been using natural fibers for many years e.g., jute is a common reinforcement in India. Natural fibers are increasingly used in automotive and packaging materials. Pakistan is an agricultural country and it is the main stay of Pakistan's economy. Thousands of tons of different crops are produced but most of their wastes do not have any useful utilization. Agricultural wastes include wheat husk, rice husk, and their straw, hemp fiber and shells of various dry fruits. These agricultural wastes can be used to prepare fiber reinforced polymer composites for commercial use. This report examines the different types of fibers available and the current status of research. Many references to the latest work on properties, processing and application have been cited in this review. (author)

  14. Machining of glass fiber reinforced polyamide

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available The machinability of a 30 wt% glass fiber reinforced polyamide (PA was investigated by means of drilling tests. A disk was cut from an extruded rod and drilled on the flat surface: thrust was acquired during drilling at different drilling speed, feed rate and drill diameter. Differential scanning calorimetry (DSC and indentation were used to characterize PA so as to evaluate the intrinsic lack of homogeneity of the extruded material. In conclusion, it was observed that the chip formation mechanism affects the thrust dependence on the machining parameters. A traditional modeling approach is able to predict thrust only in presence of a continuous chip. In some conditions, thrust increases as drilling speed increases and feed rate decreases; this evidence suggests not to consider the general scientific approach which deals the machining of plastics in analogy with metals. Moreover, the thrust can be significantly affected by the workpiece fabrication effect, as well as by the machining parameters; therefore, the fabrication effect is not negligible in the definition of an optimum for the machining process.

  15. Fiber-Reinforced Origamic Robotic Actuator.

    Science.gov (United States)

    Yi, Juan; Chen, Xiaojiao; Song, Chaoyang; Wang, Zheng

    2018-02-01

    A novel pneumatic soft linear actuator Fiber-reinforced Origamic Robotic Actuator (FORA) is proposed with significant improvements on the popular McKibben-type actuators, offering nearly doubled motion range, substantially improved force profile, and significantly lower actuation pressure. The desirable feature set is made possible by a novel soft origamic chamber that expands radially while contracts axially when pressurized. Combining this new origamic chamber with a reinforcing fiber mesh, FORA generates very high traction force (over 150N) and very large contractile motion (over 50%) at very low input pressure (100 kPa). We developed quasi-static analytical models both to characterize the motion and forces and as guidelines for actuator design. Fabrication of FORA mostly involves consumer-grade three-dimensional (3D) printing. We provide a detailed list of materials and dimensions. Fabricated FORAs were tested on a dedicated platform against commercially available pneumatic artificial muscles from Shadow and Festo to showcase its superior performances and validate the analytical models with very good agreements. Finally, a robotic joint was developed driven by two antagonistic FORAs, to showcase the benefits of the performance improvements. With its simple structure, fully characterized mechanism, easy fabrication procedure, and highly desirable performance, FORA could be easily customized to application requirements and fabricated by anyone with access to a 3D printer. This will pave the way to the wider adaptation and application of soft robotic systems.

  16. CREATION OF MUSIC WITH FIBER REINFORCED CONCRETE

    Science.gov (United States)

    Kato, Hayato; Takeuchi, Masaki; Ogura, Naoyuki; Kitahara, Yukiko; Okamoto, Takahisa

    This research focuses on the Fiber Reinforcement Concrete(FRC) and its performance on musical tones. Thepossibility of future musical instruments made of this concrete is discussed. Recently, the technical properties of FRC had been improved and the different production styles, such as unit weight of binding material and volume of fiber in the structure, hardly affects the results of the acoustics. However, the board thickness in the FRC instruments is directly related with the variety of musical tone. The FRC musical effects were compared with those produced with wood on wind instruments. The sounds were compared with those produced with woodwind instruments. The sound pressure level was affected by the material and it becomes remarkably notorious in the high frequency levels. These differences had great influence on the spectrum analysis of the tone in the wind instruments and the sensory test. The results from the sensory test show dominant performances of brightness, beauty and power in the FRC instruments compared with those made of wood.

  17. Radiation modification of glass fiber - reinforced plastics

    International Nuclear Information System (INIS)

    Allayarov, S.R.; Smirnov, Yu.N.; Lesnichaya, V.A.; Ol'khov, Yu.A.; Belov, G.P.; Dixon, D.A.; Kispert, L.D.

    2007-01-01

    Modification of glass fiber - reinforced plastics (GFRPs) by gamma-irradiation has been researched to receipt of polymeric composite materials. They were produced by the film - technology method and the cheapest thermoplastics (polythene, polyamide were used as polymeric matrixes for their manufacture. GFRPs were irradiated with Co 60 gamma-rays from a Gammatok-100 source in air and in vacuum. The strength properties of GFRPs and initial polymeric matrixes were investigated before and after radiolysis. Molecular - topological structure of the polymeric matrixes were tested by the method of thermomechanical spectroscopy. The strength properties of GFRPs depend on a parity of speeds of structural (physical) and chemical modification of the polymeric matrixes. These two processes proceed simultaneously. The structural modification includes physical transformation of polymers at preservation of their chemical structure. Covalent bonds between various macromolecules or between macromolecules and surface of fiberglasses are formed at the chemical modification of polymeric matrixes induced by radiation. Action of ionizing radiation on the used polymeric matrix results to its structurization (polythene) or to destruction (polyamide). Increasing of durability of GFRPs containing polythene is caused by formation of the optimum molecular topological structure of the polymeric matrix. (authors)

  18. Quantitative radiographic analysis of fiber reinforced polymer composites.

    Science.gov (United States)

    Baidya, K P; Ramakrishna, S; Rahman, M; Ritchie, A

    2001-01-01

    X-ray radiographic examination of the bone fracture healing process is a widely used method in the treatment and management of patients. Medical devices made of metallic alloys reportedly produce considerable artifacts that make the interpretation of radiographs difficult. Fiber reinforced polymer composite materials have been proposed to replace metallic alloys in certain medical devices because of their radiolucency, light weight, and tailorable mechanical properties. The primary objective of this paper is to provide a comparable radiographic analysis of different fiber reinforced polymer composites that are considered suitable for biomedical applications. Composite materials investigated consist of glass, aramid (Kevlar-29), and carbon reinforcement fibers, and epoxy and polyether-ether-ketone (PEEK) matrices. The total mass attenuation coefficient of each material was measured using clinical X-rays (50 kev). The carbon fiber reinforced composites were found to be more radiolucent than the glass and kevlar fiber reinforced composites.

  19. Continuous Natural Fiber Reinforced Thermoplastic Composites by Fiber Surface Modification

    Directory of Open Access Journals (Sweden)

    Patcharat Wongsriraksa

    2013-01-01

    Full Text Available Continuous natural fiber reinforced thermoplastic materials are expected to replace inorganic fiber reinforced thermosetting materials. However, in the process of fabricating the composite, it is difficult to impregnate the thermoplastic resin into reinforcement fiber because of the high melt viscosity. Therefore, intermediate material, which allows high impregnation during molding, has been investigated for fabricating continuous fiber reinforced thermoplastic composite by aligning resin fiber alongside reinforcing fiber with braiding technique. This intermediate material has been called “microbraid yarn (MBY.” Moreover, it is well known that the interfacial properties between natural fiber and resin are low; therefore, surface treatment on continuous natural fiber was performed by using polyurethane (PU and flexible epoxy (FLEX to improve the interfacial properties. The effect of surface treatment on the mechanical properties of continuous natural fiber reinforced thermoplastic composites was examined. From these results, it was suggested that surface treatment by PU with low content could produce composites with better mechanical properties.

  20. Radiographic testing of glass fiber reinforced plastic materials

    International Nuclear Information System (INIS)

    Babylas, E.

    1976-01-01

    The microradiography of glass fiber reinforced polymers allowed to obtain informations on the growth of defects during molding. A relation was established between microstructure and routine radiography. The conditions needed for obtaining good quality radiograms are analyzed [fr

  1. Fiber-reinforced Composite for Chairside Replacement of Anterior ...

    African Journals Online (AJOL)

    Fiber-reinforced Composite for Chairside Replacement of Anterior Teeth: A Case Report. ... investigation will be required to provide additional information on the survival of directly-bonded anterior fixed prosthesis made with FRC systems.

  2. Development and performance evaluation of fiber reinforced polymer bridge.

    Science.gov (United States)

    2014-03-01

    Fiber reinforced polymers (FRP) have become more popular construction materials in the last decade due to the reduction of : material costs. The installation and performance evaluation of the first FRP-wrapped balsa wood bridge in Louisiana is descri...

  3. Normal Strength Steel Fiber Reinforced Concrete Subjected to Explosive Loading

    OpenAIRE

    Mohammed Alias Yusof; Norazman Norazman; Ariffin Ariffin; Fauzi Mohd Zain; Risby Risby; CP Ng

    2011-01-01

    This paper presents the results of an experimental investigation on the behavior of plain reinforced concrete and Normal strength steel fiber reinforced concrete panels (SFRC) subjected to explosive loading. The experiment were performed by the Blast Research Unit Faculty of Engineering, University Pertahanan Nasional Malaysia A total of 8 reinforced concrete panels of 600mm x 600mm x 100mm were tested. The steel fiber reinforced concrete panels incorporated three different volume fraction, 0...

  4. Micromechanical modeling of strength and damage of fiber reinforced composites

    Energy Technology Data Exchange (ETDEWEB)

    Mishnaevsky, L. Jr.; Broendsted, P.

    2007-03-15

    The report for the first year of the EU UpWind project includes three parts: overview of concepts and methods of modelling of mechanical behavior, deformation and damage of unidirectional fiber reinforced composites, development of computational tools for the automatic generation of 3D micromechanical models of fiber reinforced composites, and micromechanical modelling of damage in FRC, and phenomenological analysis of the effect of frequency of cyclic loading on the lifetime and damage evolution in materials. (au)

  5. 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)

  6. 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)

  7. 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)

  8. 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.

  9. Bio-industrial waste silk fibroin protein and carbon nanotube induced carbonized growth of one dimensional ZnO based bio-nanosheets and their enhanced optoelectronic properties.

    Science.gov (United States)

    Saravanan, Adhimoorthy; Huang, Bohr-Ran; Kathiravan, Deepa

    2018-06-01

    High performance UV/visible photodetectors are successfully fabricated from ZnO/fibroin protein-carbon nanotube (ZFPCNT) composites using a simple hydrothermal method. The as-fabricated ZnO nanorods (ZnO NRs) and ZFPCNT nanostructures were measured under different light illuminations. The measurements showed the UV-light photoresponse of the as-fabricated ZFPCNT nanostructures (55,555) to be approximately 26454% higher than that of the as-prepared ZnO NRs (210). This photodetector can sense photons with energies considerably smaller (2.75 eV) than the band gap of ZnO (3.22 eV). It was observed that the finest distribution of fibroin and CNT into 1D ZnO resulted in rapid electron transportation and hole recombination via carbon/nitrogen dopants from the ZFPCNT. Carbon dopants create new energy levels on the conduction band of the ZFPCNT, which reduces the barrier height to allow for charge carrier transportation under light illumination. Moreover, the nitrogen dopants increase the adsorptivity and amount of oxygen vacancies in the ZFPCNT so that it exhibits fast response/recovery times both in the dark and under light illumination. The selectivity of UV light among the other types of illumination can be ascribed to the deep-level energy traps (ET) of the ZFPCNT. These significant features of ZFPCNT lead to the excellent optical properties and creation of new pathways for the production of low-cost semiconductors and bio-waste protein based UV/visible photodetectors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. High Performance Fiber Reinforced Cement Composites 6 HPFRCC 6

    CERN Document Server

    Reinhardt, Hans; Naaman, A

    2012-01-01

    High Performance Fiber Reinforced Cement Composites (HPFRCC) represent a class of cement composites whose stress-strain response in tension undergoes strain hardening behaviour accompanied by multiple cracking, leading to a high strain prior to failure. The primary objective of this International Workshop was to provide a compendium of up-to-date information on the most recent developments and research advances in the field of High Performance Fiber Reinforced Cement Composites. Approximately 65 contributions from leading world experts are assembled in these proceedings and provide an authoritative perspective on the subject. Special topics include fresh and hardening state properties; self-compacting mixtures; mechanical behavior under compressive, tensile, and shear loading; structural applications; impact, earthquake and fire resistance; durability issues; ultra-high performance fiber reinforced concrete; and textile reinforced concrete. Target readers: graduate students, researchers, fiber producers, desi...

  11. [Carbon fiber-reinforced plastics as implant materials].

    Science.gov (United States)

    Bader, R; Steinhauser, E; Rechl, H; Siebels, W; Mittelmeier, W; Gradinger, R

    2003-01-01

    Carbon fiber-reinforced plastics have been used clinically as an implant material for different applications for over 20 years.A review of technical basics of the composite materials (carbon fibers and matrix systems), fields of application,advantages (e.g., postoperative visualization without distortion in computed and magnetic resonance tomography), and disadvantages with use as an implant material is given. The question of the biocompatibility of carbon fiber-reinforced plastics is discussed on the basis of experimental and clinical studies. Selected implant systems made of carbon composite materials for treatments in orthopedic surgery such as joint replacement, tumor surgery, and spinal operations are presented and assessed. Present applications for carbon fiber reinforced plastics are seen in the field of spinal surgery, both as cages for interbody fusion and vertebral body replacement.

  12. Radiation processing for carbon fiber-reinforced polytetrafluoroethylene composite materials

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Udagawa, Akira; Morita, Yousuke

    2001-01-01

    The present work is an attempt to evaluate the performance of the fiber composites with crosslinked polytetrafluoroethylene (PTFE) as a polymer matrix by radiation. The uni-directional carbon fiber-reinforced composites were fabricated with PTFE fine powder impregnation method and then crosslinked by electron beams irradiation under selective conditions. The carbon fiber-reinforced crosslinked PTFE composites show good mechanical properties compared with crosslinked PTFE. The radiation resistance of crosslinked PTFE composites is improved more than that of crosslinked resin without fiber. (author)

  13. Hybrid fiber reinforcement and crack formation in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Pereira, E.B.; Fischer, Gregor; Barros, J.A.O.

    2011-01-01

    reinforcement systems. The research described in this paper shows that the multi-scale conception of cracking and the use of hybrid fiber reinforcements do not necessarily result in an improved tensile behavior of the composite. Particular material design requirements may nevertheless justify the use of hybrid......- to the macroscale. In this study, the performance of different fiber reinforced cementitious composites is assessed in terms of their tensile stress-crack opening behavior. The results obtained from this investigation allow a direct quantitative comparison of the behavior obtained from the different fiber...

  14. Fabrication of fiber-reinforced composites by chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M.; McLaughlin, J.C. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Probst, K.J.; Anderson, T.J. [Univ. of Florida, Gainesville, FL (United States). Dept. of Chemical Engineering; Starr, T.L. [Georgia Inst. of Tech., Atlanta, GA (United States). Dept. of Materials Science and Engineering

    1997-12-01

    Silicon carbide-based heat exchanger tubes are of interest to energy production and conversion systems due to their excellent high temperature properties. Fiber-reinforced SiC is of particular importance for these applications since it is substantially tougher than monolithic SiC, and therefore more damage and thermal shock tolerant. This paper reviews a program to develop a scaled-up system for the chemical vapor infiltration of tubular shapes of fiber-reinforced SiC. The efforts include producing a unique furnace design, extensive process and system modeling, and experimental efforts to demonstrate tube fabrication.

  15. Structural Analysis of Basalt Fiber Reinforced Plastic Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Mengal Ali Nawaz

    2014-07-01

    Full Text Available In this study, Basalt fiber reinforced plastic (BFRP wind turbine blade was analyzed and compared with Glass fiber reinforced plastic blade (GFRP. Finite element analysis (FEA of blade was carried out using ANSYS. Data for FEA was obtained by using rule of mixture. The shell element in ANSYS was used to simulate the wind turbine blade and to conduct its strength analysis. The structural analysis and comparison of blade deformations proved that BFRP wind turbine blade has better strength compared to GFRP wind turbine blade.

  16. 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.

  17. Application of Fiber Reinforcement Concrete Technique in Civil ...

    African Journals Online (AJOL)

    modulus of elasticity, high tensile strength, improved fatigue and impact resistance. Reinforcing the concrete structures with fibers such as polyester is one of the possible ways to provide all the criteria of the durable repair material. This type of reinforcement is called Fiber Reinforcement of Concrete Structures. There is an ...

  18. Environmental Degradation of Fiber-Reinforced Polymer Fasteners in Wood

    Science.gov (United States)

    Samuel L. Zelinka; Douglas R. Rammer

    2013-01-01

    This paper examines the durability of fiber-reinforced polymer (FRP) nails in treated wood. The FRP nails were exposed to four conditions: (1) accelerated weathering, consisting of exposure to ultraviolet light and condensation; (2) 100% relative humidity (RH); (3) being driven into untreated wood and exposed to 100% RH; and (4) being driven into wood treated with...

  19. Coir fiber reinforced polypropylene composite panel for automotive interior applications

    Science.gov (United States)

    Nadir Ayrilmis; Songklod Jarusombuti; Vallayuth Fueangvivat; Piyawade Bauchongkol; Robert H. White

    2011-01-01

    In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the...

  20. Fatigue life prediction of fiber reinforced concrete under flexural load

    DEFF Research Database (Denmark)

    Zhang, Jun; Stang, Henrik; Li, Victor

    1999-01-01

    This paper presents a semi-analytical method to predict fatigue behavior in flexure of fiber reinforced concrete (FRC) based on the equilibrium of force in the critical cracked section. The model relies on the cyclic bridging law, the so-called stress-crack width relationship under cyclic tensile...

  1. Stress-Strain Relationship of Synthetic Fiber Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Rosidawani

    2017-01-01

    Full Text Available Many empirical confinement models for normal and high strength concrete have been developed. Nevertheless, reported studies in the term of confinement of fiber reinforced concrete are limited. Whereas, the use of fiber reinforced concrete in structural elements has become the subject of the research and has indicated positive experiences. Since the stress-strain relationship of concrete in compression is required for analysis of structural members, the study of the stress-strain relationship for synthetic fiber reinforced concrete is substantial. The aim of the study is to examine the capabilities of the various models available in the literature to predict the actual experimental behavior of synthetic fiber reinforced high-strength concrete columns. The experimental data used are the results of the circular column specimens with the spiral spacing and the volume fraction of synthetic fiber as the test variables. The axial stress-strain curves from the tests are then compared with the various models of confinement from the literature. The performance index of each model is measured by using the coefficient of variation (COV concept of stress and strain behavior parameter. Among the confinement models, Cusson model shows the closest valid value of the coefficient of variation.

  2. Recent development in blast performance of fiber-reinforced concrete

    Science.gov (United States)

    Hajek, R.; Foglar, M.; Kohoutkova, A.

    2017-09-01

    The paper presents an overview of the recent development in blast performance of fiber reinforced concrete. The paper builds on more than ten years’ history of the research in this field by the team of the Department of Concrete and Masonry Structures of the Faculty of Civil Engineering of the Czech Technical University in Prague.

  3. Strength and thermal stability of fiber reinforced plastic composites ...

    African Journals Online (AJOL)

    Therefore, the strength properties and thermal stability of plastic composites reinforced with rattan fibers were investigated in this work. Particles of rattan species (Eremospatha macrocarpa (EM) and Laccosperma secundiflorum (LS)) were blended with High-Density Polyethylene (HDPE) to produce fiber reinforced plastic ...

  4. Compressive yielding of tungsten fiber reinforced bulk metallic glass composites

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, B.; Lee, S.-Y.; Uestuendag, E.; Aydiner, C.C.; Conner, R.D.; Bourke, M.A.M

    2003-07-15

    In-situ uniaxial compression tests were conducted on four tungsten fiber reinforced bulk metallic glass matrix composites using neutron diffraction. The results were interpreted with a finite element model. Both phases were seen to approximately obey the von Mises yield criterion. The fibers were observed to yield first and then transfer load to the matrix.

  5. Compressive yielding of tungsten fiber reinforced bulk metallic glass composites

    International Nuclear Information System (INIS)

    Clausen, B.; Lee, S.-Y.; Uestuendag, E.; Aydiner, C.C.; Conner, R.D.; Bourke, M.A.M.

    2003-01-01

    In-situ uniaxial compression tests were conducted on four tungsten fiber reinforced bulk metallic glass matrix composites using neutron diffraction. The results were interpreted with a finite element model. Both phases were seen to approximately obey the von Mises yield criterion. The fibers were observed to yield first and then transfer load to the matrix

  6. Optimising of Steel Fiber Reinforced Concrete Mix Design | Beddar ...

    African Journals Online (AJOL)

    Optimising of Steel Fiber Reinforced Concrete Mix Design. ... as a result of the loss of mixture workability that will be translated into a difficult concrete casting in site. ... An experimental study of an optimisation method of fibres in reinforced ...

  7. Single Fibre Pullout from Hybrid Fiber Reinforced Concrete

    NARCIS (Netherlands)

    Markovich, I.; Van Mier, J.G.M.; Walraven, J.C.

    2001-01-01

    Hybrid fiber reinforcement can be very efficient for improving the tensile response of the composite. In such materials, fibers of different geometries can act as bridging mechanisms over cracks of different widths. The fiber bridging efficiency depends on the interface properties, which makes

  8. Rotation capacity of self-compacting steel fiber reinforced concrete

    NARCIS (Netherlands)

    Schumacher, P.

    2006-01-01

    Steel fiber reinforced concrete (SFRC) has been used in segmental tunnel linings in the past years. In order to investigate the effect of steel fibers on the rotation capacity of plastic hinges in self-compacting concrete (SCC) the effect of the addition of fibers to SCC in compression, tension and

  9. Single fiber pullout from hybrid fiber reinforced concrete

    NARCIS (Netherlands)

    Markovich, I.; Van Mier, J.G.M.; Walraven, J.C.

    2001-01-01

    Hybrid fiber reinforcement can be very efficient for improving the tensile response of the composite. In such materials, fibers of different geometries can act as bridging mechanisms over cracks of different widths. The fiber bridging efficiency depends on the interface properties, which makes

  10. Micro-Mechanical Modeling of Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Stang, Henrik

    1999-01-01

    of Fiber Reinforced Concrete (FRC) on the micro- the meso- as well as the macro-level, i.e. modeling aspects of fiber-matrix interaction, overall constitutive modeling and structural modeling. Emphasis is placed on the micro- and meso-aspects, however, some basic results on the macro-level are also...

  11. Effects of moisture on glass fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Alzamora Guzman, Vladimir Joel; Brøndsted, Povl

    2015-01-01

    performance of wind turbine blades over their lifetime. Here, environmental moisture conditions were simulated by immersing glass fiber-reinforced polymer specimens in salt water for a period of up to 8 years. The mechanical properties of specimens were analyzed before and after immersion to evaluate...

  12. Fiber-reinforced Composite Resin Prosthesis to Restore Missing ...

    African Journals Online (AJOL)

    A fiber-reinforced composite inlay-onlay FPD was used for a single posterior tooth replacement in a patient refusing implant for psychological reasons. The FRC-FPD was made of pre-impregnated E-glass fibers (everStick, StickTeck, Turku, Finland) embedded in a resin matrix (Stick Resin, StickTeck, Turku, Finland).

  13. 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

  14. 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...

  15. Effect of Fiber Reinforcement on the Response of Structural Members

    DEFF Research Database (Denmark)

    Fischer, Gregor; Li, Victor

    2007-01-01

    This paper describes a series of investigations on the effect of fiber reinforcement on the response of structural members in direct tension and flexure under reversed cyclic loading conditions. The design approach of the fiber reinforced cementitious composite is based on fracture mechanics...... principles, which will be described in the first part of the paper along with an introduction of the relevant material properties of the resulting engineered cementitious composite (ECC). This class of composites is characterized by strain hardening and multiple cracking properties in uniaxial tension...... and an ultimate tensile strain capacity on the order of several percent. Subsequently, the synergistic effects of composite deformation mechanisms in the ECC and structural members subjected to large shear reversals are identified. Beneficial effects observed in the reinforced ECC structural members as compared...

  16. Electromagnetic configurable architectures for assessment of Carbon Fiber Reinforced Plastics

    Directory of Open Access Journals (Sweden)

    Steigmann Rozina

    2017-01-01

    Full Text Available Carbon Fiber Reinforced Plastics are used in most wide domains due their low density, lack of mechanical fatigue phenomena and high strength–to weight ratio. From electromagnetic point of view, Carbon Fiber Reinforced Plastics structure represents an inhomogeneous structure of electric conductive fibers embedded into a dielectric material, thus an electromagnetic configurable architecture can be used to evaluate above mentioned defects. The paper proposes a special sensor, send receiver type and the obtaining of electromagnetic image by post-processing each coil signals in each point of scanning, using a sub-encoding image reconstruction algorithm and super-resolution procedures. The layout of fibers can be detected interrogating only diagonal reception coils.

  17. A Study of Array Direction HDPE Fiber Reinforced Mortar

    Science.gov (United States)

    Kamsuwan, Trithos

    2018-02-01

    This paper presents the effect of array direction HDPE fiber using as the reinforced material in cement mortar. The experimental data were created reference to the efficiency of using HDPE fiber reinforced on the tensile properties of cement mortar with different high drawn ratio of HDPE fibers. The fiber with the different drawn ratio 25x (d25 with E xx), and 35x (d35 with E xx) fiber volume fraction (0%, 1.0%, 1.5%) and fiber length 20 mm. were used to compare between random direction and array direction of HDPE fibers and the stress - strain displacement relationship behavior of HDPE short fiber reinforced cement mortar were investigated. It was found that the array direction with HDPE fibers show more improved in tensile strength and toughness when reinforced in cement mortar.

  18. Elastic properties of uniaxial-fiber reinforced composites - General features

    Science.gov (United States)

    Datta, Subhendu; Ledbetter, Hassel; Lei, Ming

    The salient features of the elastic properties of uniaxial-fiber-reinforced composites are examined by considering the complete set of elastic constants of composites comprising isotropic uniaxial fibers in an isotropic matrix. Such materials exhibit transverse-isotropic symmetry and five independent elastic constants in Voigt notation: C(11), C(33), C(44), C(66), and C(13). These C(ij) constants are calculated over the entire fiber-volume-fraction range 0.0-1.0, using a scattered-plane-wave ensemple-average model. Some practical elastic constants such as the principal Young moduli and the principal Poisson ratios are considered, and the behavior of these constants is discussed. Also presented are the results for the four principal sound velocities used to study uniaxial-fiber-reinforced composites: v(11), v(33), v(12), and v(13).

  19. Steel fiber reinforced concrete subjected to elevated cyclic temperatures

    International Nuclear Information System (INIS)

    Yousif, R. A.; Rasheed, H. M.; Muhammad, H. A.

    1997-01-01

    The results from a series of tests on steel fiber reinforced concrete at elevated cyclic temperature are presented. The residual compressive strength and ultimate splitting tensile strength were nadir's on specimen ts with no fibers and with 0.5% and 1% plain steel fibers over a temperature range of 300-700 C. concrete was subjected to one, two or three cycles of heating and cooling. In general the exposure to temperature decreased the strength of concrete, although the number of heating cycles seems only to have a secondary effect. The results also show that the steel fiber reinforced concrete performs better than plain concrete. Two equations were suggested to predict the strength of concrete and the results show good agreement with the experimental values. . (authors). 10 refs., 1 tabs. 3 figs

  20. Basalt fiber reinforced porous aggregates-geopolymer based cellular material

    Science.gov (United States)

    Luo, Xin; Xu, Jin-Yu; Li, Weimin

    2015-09-01

    Basalt fiber reinforced porous aggregates-geopolymer based cellular material (BFRPGCM) was prepared. The stress-strain curve has been worked out. The ideal energy-absorbing efficiency has been analyzed and the application prospect has been explored. The results show the following: fiber reinforced cellular material has successively sized pore structures; the stress-strain curve has two stages: elastic stage and yielding plateau stage; the greatest value of the ideal energy-absorbing efficiency of BFRPGCM is 89.11%, which suggests BFRPGCM has excellent energy-absorbing property. Thus, it can be seen that BFRPGCM is easy and simple to make, has high plasticity, low density and excellent energy-absorbing features. So, BFRPGCM is a promising energy-absorbing material used especially in civil defense engineering.

  1. 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.

  2. Microstructure and mechanical properties of carbon fiber reinforced ...

    Indian Academy of Sciences (India)

    68

    Alumina; composites; carbon fiber reinforcement; sol; mechanical properties. 1. Introduction ... The reinforcement was 3D carbon fiber (T300 3k, ex-PAN carbon fiber ... where f(a/H) = 2.9(a/H)1/2 – 4.6(a/H)3/2 + 21.8(a/H)5/2. – 37.6(a/H)7/2 + ...

  3. Performance of Lightweight Natural-Fiber Reinforced Concrete

    OpenAIRE

    Hardjasaputra Harianto; Ng Gino; Urgessa Girum; Lesmana Gabriella; Sidharta Steven

    2017-01-01

    Concrete, the most common construction material, has negligible tension capacity. However, a reinforcement material such as natural fibers, can be used to improve the tensile properties of concrete. This paper presents experiments conducted on Super Lightweight Concrete mixed with coconut fibers (SLNFRC). Coconut fibers are regarded as one of the toughest natural fibers to strengthen concrete. Coconut fiber reinforced composites have been considered as a sustainable construction material beca...

  4. Elastic constants and internal friction of fiber-reinforced composites

    International Nuclear Information System (INIS)

    Ledbetter, H.M.

    1982-01-01

    We review recent experimental studies at NBS on the anisotropic elastic constants and internal friction of fiber-reinforced composites. Materials that were studied include: boron-aluminum, boron-epoxy, graphite-epoxy, glass-epoxy, and aramid-epoxy. In all cases, elastic-constant direction dependence could be described by relationships developed for single crystals of homogeneous materials. Elastic stiffness and internal friction were found to vary inversely

  5. Fabrication of fiber-reinforced composites by chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Matlin, W.M.; Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States)

    1996-08-01

    Processing equipment for the infiltration of fiber-reinforced composite tubes is being designed that incorporates improvements over the equipment used to infiltrate disks. A computer-controlled machine-man interface is being developed to allow for total control of all processing variables. Additionally, several improvements are being made to the furnace that will reduce the complexity and cost of the process. These improvements include the incorporation of free standing preforms, cast mandrels, and simpler graphite heating elements.

  6. Ceramic fiber reinforced glass-ceramic matrix composite

    Science.gov (United States)

    Bansal, Narottam P. (Inventor)

    1993-01-01

    A slurry of BSAS glass powders is cast into tapes which are cut to predetermined sizes. Mats of continuous chemical vapor deposition (CVD)-SiC fibers are alternately stacked with these matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite which is heated to burn out organic constituents. The remaining interim material is then hot-pressed to form a BSAS glass-ceramic fiber-reinforced composite.

  7. Properties of Fiber-Reinforced Mortars Incorporating Nano-Silica

    OpenAIRE

    Ahmed Ghazy; Mohamed T. Bassuoni; Eugene Maguire; Mark O’Loan

    2016-01-01

    Repair and rehabilitation of deteriorating concrete elements are of significant concern in many infrastructural facilities and remain a challenging task. Concerted research efforts are needed to develop repair materials that are sustainable, durable, and cost-effective. Research data show that fiber-reinforced mortars/concretes have superior performance in terms of volume stability and toughness. In addition, it has been recently reported that nano-silica particles can generally improve the m...

  8. Behaviour of fiber reinforced concrete slabs under impact loading

    International Nuclear Information System (INIS)

    Huelsewig, M.; Stilp, A.; Pahl, H.

    1982-01-01

    The behaviour of steel fiber reinforced concrete slabs under impact loads has been investigated. The results obtained show that fracturing and spallation effects are reduced to a large extend due to the high energy absorption and the increased yield strength of this material. Crater depths are comparable to those obtained using normal concrete targets. Systematic tests using different fiber types and dimensions show that the terminal ballistic behaviour is strongly dependent on these parameters. (orig.) [de

  9. Tensile strength of woven yarn kenaf fiber reinforced polyester composites

    OpenAIRE

    A.E. Ismail; M.A. Che Abdul Aziz

    2015-01-01

    This paper presents the tensile strength of woven kenaf fiber reinforced polyester composites. The as-received yarn kenaf fiber is weaved and then aligned into specific fiber orientations before it is hardened with polyester resin. The composite plates are shaped according to the standard geometry and uni-axially loaded in order to investigate the tensile responses. Two important parameters are studied such as fiber orientations and number of layers. According to the results, it is shown that...

  10. Advance study of fiber-reinforced self-compacting concrete

    Science.gov (United States)

    Mironova, M.; Ivanova, M.; Naidenov, V.; Georgiev, I.; Stary, J.

    2015-10-01

    Incorporation in concrete composition of steel macro- and micro - fiber reinforcement with structural function increases the degree of ductility of typically brittle cement-containing composites, which in some cases can replace completely or partially conventional steel reinforcement in the form of rods and meshes. Thus, that can reduce manufacturing, detailing and placement of conventional reinforcement, which enhances productivity and economic efficiency of the building process. In this paper, six fiber-reinforced with different amounts of steel fiber cement-containing self-compacting compositions are investigated. The results of some of their main strength-deformation characteristics are presented. Advance approach for the study of structural and material properties of these type composites is proposed by using the methods of industrial computed tomography. The obtained original tomography results about the microstructure and characteristics of individual structural components make it possible to analyze the effective macro-characteristics of the studied composites. The resulting analytical data are relevant for the purposes of multi-dimensional modeling of these systems. Multifactor structure-mechanical analysis of the obtained with different methods original scientific results is proposed. It is presented a conclusion of the capabilities and effectiveness of complex analysis in the studies to characterize the properties of self-compacting fiber-reinforced concrete.

  11. Advance study of fiber-reinforced self-compacting concrete

    International Nuclear Information System (INIS)

    Mironova, M.; Ivanova, M.; Naidenov, V.; Georgiev, I.; Stary, J.

    2015-01-01

    Incorporation in concrete composition of steel macro- and micro – fiber reinforcement with structural function increases the degree of ductility of typically brittle cement-containing composites, which in some cases can replace completely or partially conventional steel reinforcement in the form of rods and meshes. Thus, that can reduce manufacturing, detailing and placement of conventional reinforcement, which enhances productivity and economic efficiency of the building process. In this paper, six fiber-reinforced with different amounts of steel fiber cement-containing self-compacting compositions are investigated. The results of some of their main strength-deformation characteristics are presented. Advance approach for the study of structural and material properties of these type composites is proposed by using the methods of industrial computed tomography. The obtained original tomography results about the microstructure and characteristics of individual structural components make it possible to analyze the effective macro-characteristics of the studied composites. The resulting analytical data are relevant for the purposes of multi-dimensional modeling of these systems. Multifactor structure-mechanical analysis of the obtained with different methods original scientific results is proposed. It is presented a conclusion of the capabilities and effectiveness of complex analysis in the studies to characterize the properties of self-compacting fiber-reinforced concrete

  12. Engineering Properties of Treated Natural Hemp Fiber-Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Xiangming Zhou

    2017-06-01

    Full Text Available In recent years, the construction industry has seen a significant rise in the use of natural fibers, for producing building materials. Research has shown that treated hemp fiber-reinforced concrete (THFRC can provide a low-cost building material for residential and low-rise buildings, while achieving sustainable construction and meeting future environmental targets. This study involved enhancing the mechanical properties of hemp fiber-reinforced concrete through the Ca(OH2 solution pretreatment of fibers. Both untreated (UHFRC and treated (THFRC hemp fiber-reinforced concrete were tested containing 15-mm length fiber, at a volume fraction of 1%. From the mechanical strength tests, it was observed that the 28-day tensile and compressive strength of THFRC was 16.9 and 10% higher, respectively, than UHFRC. Based on the critical stress intensity factor (KICs and critical strain energy release rate (GICs, the fracture toughness of THFRC at 28 days was also found to be 7–13% higher than UHFRC. Additionally, based on the determined brittleness number (Q and modulus of elasticity, the THFRC was found to be 11% less brittle and 10.8% more ductile. Furthermore, qualitative analysis supported many of the mechanical strength findings through favorable surface roughness observed on treated fibers and resistance to fiber pull-out.

  13. Experimental study on mix proportion of fiber reinforced cementitious composites

    Science.gov (United States)

    Jia, Yi; Zhao, Renda; Liao, Ping; Li, Fuhai; Yuan, Yuan; Zhou, Shuang

    2017-10-01

    To study the mechanical property of fiber reinforced cementations composites influenced by the fiber length, quartz sand diameter, matrix of water cement ratio, volume fraction of fiber and magnesium acrylate solution. Several 40×40×160 mm standard test specimens, "8" specimens and long "8" specimens and 21 groups of fiber concrete specimens were fabricated. The flexural, compressive and uniaxial tensile strength were tested by using the bending resistance, compression resistance and electronic universal testing machine. The results show that flexural and compressive strength of fiber reinforced cementations composites increases along with the increase of quartz sand diameter, with the growth of the PVA fiber length increases; When the water-binder ratio is 0.25 and powder-binder ratio is 0.3, the PVA fiber content is 1.5% of the mass of cementations materials, there is a phenomenon of strain hardening; The addition of magnesium acrylate solution reduces the tensile strength of PVA fiber reinforced cementations composites, the tensile strength of the specimens in the curing age of 7d is decreased by about 21% and the specimens in curing age of 28d is decreased by more than 50%.

  14. Advance study of fiber-reinforced self-compacting concrete

    Energy Technology Data Exchange (ETDEWEB)

    Mironova, M., E-mail: mirona@imbm.bas.bg; Ivanova, M., E-mail: magdalena.ivanova@imbm.bas.bg; Naidenov, V., E-mail: valna53@mail.bg [Institute of Mechanics, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 4, Sofia 1113 (Bulgaria); Georgiev, I., E-mail: ivan.georgiev@parallel.bas.bg [Institute of Information and Communication Technologies & Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev str., Sofia 1113 (Bulgaria); Stary, J., E-mail: stary@ugn.cas.cz [Institute of Geonics Czech Academy of Sciences, Studentska str., Ostrava 1768 (Czech Republic)

    2015-10-28

    Incorporation in concrete composition of steel macro- and micro – fiber reinforcement with structural function increases the degree of ductility of typically brittle cement-containing composites, which in some cases can replace completely or partially conventional steel reinforcement in the form of rods and meshes. Thus, that can reduce manufacturing, detailing and placement of conventional reinforcement, which enhances productivity and economic efficiency of the building process. In this paper, six fiber-reinforced with different amounts of steel fiber cement-containing self-compacting compositions are investigated. The results of some of their main strength-deformation characteristics are presented. Advance approach for the study of structural and material properties of these type composites is proposed by using the methods of industrial computed tomography. The obtained original tomography results about the microstructure and characteristics of individual structural components make it possible to analyze the effective macro-characteristics of the studied composites. The resulting analytical data are relevant for the purposes of multi-dimensional modeling of these systems. Multifactor structure-mechanical analysis of the obtained with different methods original scientific results is proposed. It is presented a conclusion of the capabilities and effectiveness of complex analysis in the studies to characterize the properties of self-compacting fiber-reinforced concrete.

  15. An environmentally benign route for the development of compressible, thermally insulating and fire retardant aerogels through self-assembling the silk fibroin biopolymer inside the silica structure - An approach towards 3D printing of aerogels.

    Science.gov (United States)

    Maleki, Hajar; Montes, Susan; Hayati-Roodbari, Nastaran; Putz, Florian; Huesing, Nicola

    2018-06-04

    Thanks to the exceptional materials properties of silica aerogels, this fascinating highly porous material has found high performance and real-life applications in various modern industries. However, a requirement for a broadening of these applications is based on the further improvement of their properties especially with regard to mechanical strength and post-synthesis processability with minimum compromise to the other physical properties. Here, we report an entirely novel, simple and aqueous based synthesis approach to prepare mechanically robust aerogel hybrids by co-gelation of silk fibroin (SF) biopolymer, extracted from silkworm cocoons. The synthesis is based on a one-step sequential processes of acid catalysis (physical) crosslinking of the SF biopolymer and simultaneous polycondensation of tetramethyl orthosilicate (TMOS), in the presence of 5-(trimethoxysilyl)pentanoic acid (TMSPA) as a coupling agent and subsequent solvent exchange and supercritical drying. Extensive characterizations by solid-state 1H-NMR, 29Si-NMR, and 2D 1H-29Si heteronuclear correlation (HETCOR) MAS NMR spectroscopy as well as various microscopic techniques (SEM, TEM) and mechanical assessment, confirmed the molecular-level homogeneity of the hybrid nanostructure. The developed silica-SF aerogel hybrids contained an improved set of material properties, such as low density (ρb, average = 0.11 - 0.2 g cm-3), high porosity (~90%), high specific surface area (~ 400-800 m2 g-1), excellent flexibility in compression (up to 80% of strain) with three-order of magnitude improvement in the Young's modulus over that of pristine silica aerogels. In addition, the silica-SF hybrid aerogels are fire retardant and demonstrated excellent thermal insulation performance with thermal conductivities (λ) of (0.033-0.039 Wm-1 K-1). As a further advantage, the formulated hybrid silica-SF aerogel showed an excellent printability in the wet state using a micro-extrusion based 3D printing approach. The

  16. Review of Japanese recommendations on design and construction of different classes of fiber reinforced concrete and application examples

    DEFF Research Database (Denmark)

    Uchida, Yuichi; Fischer, Gregor; Hishiki, Yoshihiro

    2008-01-01

    The development of concrete and cementitious composites with fiber reinforcement to improve the tensile load-deformation behavior has resulted in three distinct classes of materials. These include conventional Fiber Reinforced Concrete (FRC) with tension softening response, High Performance Fiber...... Reinforced Cement Composites (HPFRCC) with strain hardening and multiple cracking behavior, and Ultra High-strength Fiber Reinforced concrete (UFC) with increased tensile strength. The recommendations on the design, production, and application of these classes of fiber reinforced concrete have been...

  17. State-of-Practice on the Dynamic Response of Structures Strengthened with Fiber Reinforced Polymers (FRPs)

    Science.gov (United States)

    2015-07-01

    entitled “Design guidelines for blast strengthening of concrete and masonry structures using Fiber - Reinforced Polymer (FRP).” Seismic provision...2 Reinforced Concrete Fiber Reinforced Polymers are frequently used to retrofit and repair reinforced concrete structures. Most of the work...tested 72 laboratory-size beams (3-in. by 3-in. cross-section and 30–in. long) of unreinforced and nylon fiber reinforced light-weight concrete that

  18. 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.

  19. An Investigation of Interfacial Fatigue in Fiber Reinforced Composites

    Science.gov (United States)

    Yanhua, Chen; Zhifei, Shi

    2005-09-01

    Based on the shear-lag model and the modified degradation formula for coefficient of friction, the interfacial fatigue and debonding for fiber reinforced composites under cyclic loading are studied. The loading condition is chosen as the kind that is the most frequently used in fiber-pull-out experiments. The stress components in the debonded and bonded regions are obtained according to the maximum and minimum applied loading. By the aid of theory of fracture mechanics and Paris formula, the governing equation is solved numerically and the interfacial debonding is simulated. The relationships between the parameters (such as the debond rate, debond length, debond force) and the number of cycles are obtained.

  20. Homogenization of long fiber reinforced composites including fiber bending effects

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Niordson, Christian Frithiof

    2016-01-01

    This paper presents a homogenization method, which accounts for intrinsic size effects related to the fiber diameter in long fiber reinforced composite materials with two independent constitutive models for the matrix and fiber materials. A new choice of internal kinematic variables allows...... of the reinforcing fibers is captured by higher order strain terms, resulting in an accurate representation of the micro-mechanical behavior of the composite. Numerical examples show that the accuracy of the proposed model is very close to a non-homogenized finite-element model with an explicit discretization...

  1. Advanced rotary engine components utilizing fiber reinforced Mg castings

    Science.gov (United States)

    Goddard, D.; Whitman, W.; Pumphrey, R.; Lee, C.-M.

    1986-01-01

    Under a two-phase program sponsored by NASA, the technology for producing advanced rotary engine components utilizing graphite fiber-reinforced magnesium alloy casting is being developed. In Phase I, the successful casting of a simulated intermediate housing was demonstrated. In Phase II, the goal is to produce an operating rotor housing. The effort involves generation of a material property data base, optimization of parameters, and development of wear- and corrosion-resistant cast surfaces and surface coatings. Results to date are described.

  2. Elastic properties of rigid fiber-reinforced composites

    Science.gov (United States)

    Chen, J.; Thorpe, M. F.; Davis, L. C.

    1995-05-01

    We study the elastic properties of rigid fiber-reinforced composites with perfect bonding between fibers and matrix, and also with sliding boundary conditions. In the dilute region, there exists an exact analytical solution. Around the rigidity threshold we find the elastic moduli and Poisson's ratio by decomposing the deformation into a compression mode and a rotation mode. For perfect bonding, both modes are important, whereas only the compression mode is operative for sliding boundary conditions. We employ the digital-image-based method and a finite element analysis to perform computer simulations which confirm our analytical predictions.

  3. Suppression of electromechanical instability in fiber-reinforced dielectric elastomers

    Directory of Open Access Journals (Sweden)

    Rui Xiao

    2016-03-01

    Full Text Available The electromechanical instability of dielectric elastomers has been a major challenge for the application of this class of active materials. In this work, we demonstrate that dielectric elastomers filled with soft fiber can suppress the electromechanical instability and achieve large deformation. Specifically, we developed a constitutive model to describe the dielectric and mechanical behaviors of fiber-reinforced elastomers. The model was applied to study the influence of stiffness, nonlinearity properties and the distribution of fiber on the instability of dielectric membrane under an electric field. The results show that there exists an optimal fiber distribution condition to achieve the maximum deformation before failure.

  4. Load sharing in tungsten fiber reinforced Kanthal composites

    International Nuclear Information System (INIS)

    Clausen, B.; Bourke, Mark A.M.; Brown, Donald W.; Ustuendag, E.

    2006-01-01

    The load sharing in three tungsten fiber reinforced Kanthal matrix composites (with fiber volume fractions of 10, 20 and 30%) have been determined using in situ neutron diffraction measurements. The expected iso-strain region was limited in the 20 and 30% composites due to thermal residual stresses. The experimental data have been used to validate the predictions of a unit-cell finite element model. The model was able to accurately predict the measured in situ loading data for all three composites using the same material properties for all calculations

  5. Load sharing in tungsten fiber reinforced Kanthal composites

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, B. [Los Alamos National Laboratory, LANSCE-12, P.O. Box 1663, MS H805, Los Alamos, NM 87545 (United States)]. E-mail: clausen@lanl.gov; Bourke, Mark A.M. [Los Alamos National Laboratory, MST-8, P.O. Box 1663, MS H805, Los Alamos, NM 87545 (United States); Brown, Donald W. [Los Alamos National Laboratory, MST-8, P.O. Box 1663, MS H805, Los Alamos, NM 87545 (United States); Ustuendag, E. [California Institute of Technology, Keck Laboratory, M/C 138-78, 1200 E. California Blvd., Pasadena, CA 91125 (United States)

    2006-04-15

    The load sharing in three tungsten fiber reinforced Kanthal matrix composites (with fiber volume fractions of 10, 20 and 30%) have been determined using in situ neutron diffraction measurements. The expected iso-strain region was limited in the 20 and 30% composites due to thermal residual stresses. The experimental data have been used to validate the predictions of a unit-cell finite element model. The model was able to accurately predict the measured in situ loading data for all three composites using the same material properties for all calculations.

  6. Flexural fatigue behavior of steel fiber reinforced concrete structures

    International Nuclear Information System (INIS)

    Chang, G.I.; Chai, W.K.; Park, C.W.; Min, I.K.

    1993-01-01

    In this thesis, the fatigue tests are performed on a series of SFRC (steel fiber reinforced concrete) to investigate the fatigue behavior of SFRC varing with the steel fiber contents and the steel fiber aspect ratios. Thirty SFRC beams are used in this test. The relationships between repeated loading cycle and mid-span deflection of the beams are observed under the three-point loading system. From the test results, the effects of the fiber content and the fiber aspect ratio on the concrete fatigue behavior were studied. According to the regression technique, some empirical formulae for predicting the fatigue strength of SFRC beams are also suggested. (author)

  7. Design of Ultra High Performance Fiber Reinforced Concrete Shells

    DEFF Research Database (Denmark)

    Jepsen, Michael S.; Lambertsen, Søren Heide; Damkilde, Lars

    2013-01-01

    Fiber Reinforced Concrete shell. The major challenge in the design phase has been securing sufficient stiffness of the structure while keeping the weight at a minimum. The weight/stiffness issue has been investigated by means of the finite element method, to optimize the structure regarding overall......The paper treats the redesign of the float structure of the Wavestar wave energy converter. Previously it was designed as a glass fiber structure, but due to cost reduction requirements a redesign has been initiated. The new float structure will be designed as a double curved Ultra High Performance...

  8. MECHANICAL CHARACTERIZATION AND ANALYSIS OF RANDOMLY DISTRIBUTED SHORT BANANA FIBER REINFORCED EPOXY COMPOSITES

    Directory of Open Access Journals (Sweden)

    R. K. Misra

    2014-03-01

    Full Text Available Short banana fiber reinforced composites have been prepared in laboratory to determine mechanical properties. It has been observed that as soon as the percentage of the banana fiber increases slightly there is a tremendous increase in ultimate tensile strength, % of strain and young modulus of elasticity. Reinforcement of banana fibers in epoxy resin increases stiffness and decreases damping properties of the composites. Therefore, 2.468% banana fiber reinforced composite plate stabilizes early as compared to 7.7135 % banana fiber reinforced composite plate but less stiff as compared to 7.7135 % banana fiber reinforced composite plate

  9. Electrochemical corrosion of carbon-fiber-reinforced plastic-metal electrode couples in corrosion media

    International Nuclear Information System (INIS)

    Chukalovskaya, T.V.; Shcherbakov, A.I.; Chigirinskaya, L.A.; Bandurkin, V.V.; Medova, I.L.; Chukalovskij, P.A.

    1995-01-01

    Polarization diagrams, obtained for carbon-fiber-reinforced plastic(cathode)-metallic material(anode) contact couples are analyzed to predict the corrosion behaviour of some technical metals and alloys (carbon steel, stainless steels, brass, aluminium, titanium) in contact with carbon-fiber-reinforced plastic in differen agressive media (H 2 SO 4 , HCl, H 3 PO 4 , NaOH solutions in wide temperature and concentration range, synthetic seawater at 30 and 50 deg C). The predicted behaviour was supported by direct investigation into carbon-fiber-reinforced plastic-titanium and carbon-fiber-reinforced plastic-aluminium contact couples at different square ratios. 6 refs.; 4 figs

  10. Dynamic shear-lag model for understanding the role of matrix in energy dissipation in fiber-reinforced composites.

    Science.gov (United States)

    Liu, Junjie; Zhu, Wenqing; Yu, Zhongliang; Wei, Xiaoding

    2018-07-01

    Lightweight and high impact performance composite design is a big challenge for scientists and engineers. Inspired from well-known biological materials, e.g., the bones, spider silk, and claws of mantis shrimp, artificial composites have been synthesized for engineering applications. Presently, the design of ballistic resistant composites mainly emphasizes the utilization of light and high-strength fibers, whereas the contribution from matrix materials receives less attention. However, recent ballistic experiments on fiber-reinforced composites challenge our common sense. The use of matrix with "low-grade" properties enhances effectively the impact performance. In this study, we establish a dynamic shear-lag model to explore the energy dissipation through viscous matrix materials in fiber-reinforced composites and the associations of energy dissipation characteristics with the properties and geometries of constituents. The model suggests that an enhancement in energy dissipation before the material integrity is lost can be achieved by tuning the shear modulus and viscosity of a matrix. Furthermore, our model implies that an appropriately designed staggered microstructure, adopted by many natural composites, can repeatedly activate the energy dissipation process and thus improve dramatically the impact performance. This model demonstrates the role of matrix in energy dissipation, and stimulates new advanced material design concepts for ballistic applications. Biological composites found in nature often possess exceptional mechanical properties that man-made materials haven't be able to achieve. For example, it is predicted that a pencil thick spider silk thread can stop a flying Boeing airplane. Here, by proposing a dynamic shear-lag model, we investigate the relationships between the impact performance of a composite with the dimensions and properties of its constituents. Our analysis suggests that the impact performance of fiber-reinforced composites could improve

  11. 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 ...

  12. Mechanical Properties of Fiber Reinforced Lightweight Concrete Containing Surfactant

    Directory of Open Access Journals (Sweden)

    Yoo-Jae Kim

    2010-01-01

    Full Text Available Fiber reinforced aerated lightweight concrete (FALC was developed to reduce concrete's density and to improve its fire resistance, thermal conductivity, and energy absorption. Compression tests were performed to determine basic properties of FALC. The primary independent variables were the types and volume fraction of fibers, and the amount of air in the concrete. Polypropylene and carbon fibers were investigated at 0, 1, 2, 3, and 4% volume ratios. The lightweight aggregate used was made of expanded clay. A self-compaction agent was used to reduce the water-cement ratio and keep good workability. A surfactant was also added to introduce air into the concrete. This study provides basic information regarding the mechanical properties of FALC and compares FALC with fiber reinforced lightweight concrete. The properties investigated include the unit weight, uniaxial compressive strength, modulus of elasticity, and toughness index. Based on the properties, a stress-strain prediction model was proposed. It was demonstrated that the proposed model accurately predicts the stress-strain behavior of FALC.

  13. Electromechanical behavior of fiber-reinforced dielectric elastomer membrane

    Directory of Open Access Journals (Sweden)

    Chi Li

    2015-04-01

    Full Text Available Based on its large deformation, light weight, and high energy density, dielectric elastomer (DE has been used as driven muscle in many areas. We design the fiber-reinforced DE membrane by adding fibers in the membrane. The deformation and driven force direction of the membrane can be tuned by changing the fiber arrangements. The actuation in the perpendicular direction of the DE membrane with long fibers first increases and then decreases by the increasing of the fiber spacing in the perpendicular direction. The horizontal actuation of the membrane decreases by decreasing the spacing of short fibers. In the membrane-inflating structure, the radially arranged fibers will break the axisymmetric behavior of the structure. The top area of the inflated balloon without fiber will buckle up when the voltage reaches a certain level. Finite element simulations based on nonlinear field theory are conducted to investigate the effects of fiber arrangement and verify the experimental results. This work can guide the design of fiber-reinforced DE.

  14. Numerical modeling of hybrid fiber-reinforced concrete (hyfrc)

    International Nuclear Information System (INIS)

    Hameed, R.; Turatsinze, A.

    2015-01-01

    A model for numerical simulation of mechanical response of concrete reinforced with slipping and non slipping metallic fibers in hybrid form is presented in this paper. Constitutive law used to model plain concrete behaviour is based on plasticity and damage theories, and is capable to determine localized crack opening in three dimensional (3-D) systems. Behaviour law used for slipping metallic fibers is formulated based on effective stress carried by these fibers after when concrete matrix is cracked. A continuous approach is proposed to model the effect of addition of non-slipping metallic fibers in plain concrete. This approach considers the constitutive law of concrete matrix with increased fracture energy in tension obtained experimentally in direct tension tests on Fiber Reinforced Concrete (FRC). To simulate the mechanical behaviour of hybrid fiber-reinforced concrete (HyFRC), proposed approaches to model non-slipping metallic fibers and constitutive law of plain concrete and slipping fibers are used simultaneously without any additive equation. All the parameters used by the proposed model have physical meanings and are determined through experiments or drawn from literature. The model was implemented in Finite Element (FE) Code CASTEM and tested on FRC prismatic notched specimens in flexure. Model prediction showed good agreement with experimental results. (author)

  15. A micromorphic model for steel fiber reinforced concrete.

    Science.gov (United States)

    Oliver, J; Mora, D F; Huespe, A E; Weyler, R

    2012-10-15

    A new formulation to model the mechanical behavior of high performance fiber reinforced cement composites with arbitrarily oriented short fibers is presented. The formulation can be considered as a two scale approach, in which the macroscopic model, at the structural level, takes into account the mesostructural phenomenon associated with the fiber-matrix interface bond/slip process. This phenomenon is contemplated by including, in the macroscopic description, a micromorphic field representing the relative fiber-cement displacement. Then, the theoretical framework, from which the governing equations of the problem are derived, can be assimilated to a specific case of the material multifield theory. The balance equation derived for this model, connecting the micro stresses with the micromorphic forces, has a physical meaning related with the fiber-matrix bond slip mechanism. Differently to previous procedures in the literature, addressed to model fiber reinforced composites, where this equation has been added as an additional independent ingredient of the methodology, in the present approach it arises as a natural result derived from the multifield theory. Every component of the composite is defined with a specific free energy and constitutive relation. The mixture theory is adopted to define the overall free energy of the composite, which is assumed to be homogeneously constituted, in the sense that every infinitesimal volume is occupied by all the components in a proportion given by the corresponding volume fraction. The numerical model is assessed by means of a selected set of experiments that prove the viability of the present approach.

  16. Properties of Fiber-Reinforced Mortars Incorporating Nano-Silica

    Directory of Open Access Journals (Sweden)

    Ahmed Ghazy

    2016-02-01

    Full Text Available Repair and rehabilitation of deteriorating concrete elements are of significant concern in many infrastructural facilities and remain a challenging task. Concerted research efforts are needed to develop repair materials that are sustainable, durable, and cost-effective. Research data show that fiber-reinforced mortars/concretes have superior performance in terms of volume stability and toughness. In addition, it has been recently reported that nano-silica particles can generally improve the mechanical and durability properties of cement-based systems. Thus, there has been a growing interest in the use of nano-modified fiber-reinforced cementitious composites/mortars (NFRM in repair and rehabilitation applications of concrete structures. The current study investigates various mechanical and durability properties of nano-modified mortar containing different types of fibers (steel, basalt, and hybrid (basalt and polypropylene, in terms of compressive and flexural strengths, toughness, drying shrinkage, penetrability, and resistance to salt-frost scaling. The results highlight the overall effectiveness of the NFRM owing to the synergistic effects of nano-silica and fibers.

  17. Biodegradation of flax fiber reinforced poly lactic acid

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available Woven and nonwoven flax fiber reinforced poly lactic acid (PLA biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM. Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20–25% loss in weight after 50–60 days. On the other hand, in presence of dicumyl peroxide (as additive, biodegradation of the composites was relatively slow as confirmed by only 5–10% loss in weight even after 80–90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add different amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site.

  18. Natural Kenaf Fiber Reinforced Composites as Engineered Structural Materials

    Science.gov (United States)

    Dittenber, David B.

    The objective of this work was to provide a comprehensive evaluation of natural fiber reinforced polymer (NFRP)'s ability to act as a structural material. As a chemical treatment, aligned kenaf fibers were treated with sodium hydroxide (alkalization) in different concentrations and durations and then manufactured into kenaf fiber / vinyl ester composite plates. Single fiber tensile properties and composite flexural properties, both in dry and saturated environments, were assessed. Based on ASTM standard testing, a comparison of flexural, tensile, compressive, and shear mechanical properties was also made between an untreated kenaf fiber reinforced composite, a chemically treated kenaf fiber reinforced composite, a glass fiber reinforced composite, and oriented strand board (OSB). The mechanical properties were evaluated for dry samples, samples immersed in water for 50 hours, and samples immersed in water until saturation (~2700 hours). Since NFRPs are more vulnerable to environmental effects than synthetic fiber composites, a series of weathering and environmental tests were conducted on the kenaf fiber composites. The environmental conditions studied include real-time outdoor weathering, elevated temperatures, immersion in different pH solutions, and UV exposure. In all of these tests, degradation was found to be more pronounced in the NFRPs than in the glass FRPs; however, in nearly every case the degradation was less than 50% of the flexural strength or stiffness. Using a method of overlapping and meshing discontinuous fiber ends, large mats of fiber bundles were manufactured into composite facesheets for structural insulated panels (SIPs). The polyisocyanurate foam cores proved to be poorly matched to the strength and stiffness of the NFRP facesheets, leading to premature core shear or delamination failures in both flexure and compressive testing. The NFRPs were found to match well with the theoretical stiffness prediction methods of classical lamination

  19. 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.

  20. Numerical investigation of friction joint between Basalt Fiber Reinforced Composites and aluminum

    DEFF Research Database (Denmark)

    Costache, Andrei; Berggreen, Christian; Sivebæk, Ion Marius

    2016-01-01

    and stiffer flexible risers, which would be well suited for ultra deep water applications. This paper develops a new finite element model used for evaluating the efficiency of anchoring flat unidirectional fiber reinforced tendons in a mechanical grip. It consists two flat grips with the fiber reinforced...

  1. 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)

  2. 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)

  3. 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.

  4. Preliminary Study on Impact Resistances of Fiber Reinforced Concrete Applied Nuclear Power Plants

    International Nuclear Information System (INIS)

    Jin, Byeong Moo; Kim, Young Jin; Jeon, Se Jin

    2013-01-01

    Studies to improve the impact resistance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application ratio, are in progress. Authors assessed first the impact resistance of concrete walls depending upon fiber types and missile impact velocities. The safety assessment of nuclear power plants against large civil aircraft crashes have been accomplished for normal concrete and fiber reinforced concretes in this study. Studies on the safety assessments on the nuclear power plants against large civil aircraft crashes are ongoing actively. As a step of evaluating the applicability of fiber reinforced concrete in means of ensuring more structural safety of the nuclear power plants against impact, the impact resistance for the 1% steel and 2% polyamide fiber reinforced concretes have been evaluated. For reactor containment building structures, it seem there is no impact resistance enhancement of fiber reinforced concrete applied to reactor containment building in the cases of impact velocity 150 m/sec considered in this study. However this results from the pre-stressing forces which introduce compressive stresses in concrete wall and dome section of reactor containment building. Nonetheless there may be benefits to apply fiber reinforced concrete to nuclear power plants. For double containment type reactor containment building, the outer structure is a reinforced concrete structure. The impact resistances for non pre-stressed cylindrical reactor containment buildings are enhanced by 23 to 47 % for 2 % polyamide fiber reinforced concretes and 1 % steel fiber reinforced concretes respectively. For other buildings such as auxiliary building, compound building and fuel storage building surrounding the reactor containment building, there are so many reinforced concrete walls which are anticipated some enhancements of impact resistance by using fiber reinforced concretes. And heavier or faster large civil aircraft impacts produce higher

  5. Preliminary Study on Impact Resistances of Fiber Reinforced Concrete Applied Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Byeong Moo; Kim, Young Jin; Jeon, Se Jin [Daewoo E and C Co. Ltd., Suwon (Korea, Republic of)

    2013-10-15

    Studies to improve the impact resistance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application ratio, are in progress. Authors assessed first the impact resistance of concrete walls depending upon fiber types and missile impact velocities. The safety assessment of nuclear power plants against large civil aircraft crashes have been accomplished for normal concrete and fiber reinforced concretes in this study. Studies on the safety assessments on the nuclear power plants against large civil aircraft crashes are ongoing actively. As a step of evaluating the applicability of fiber reinforced concrete in means of ensuring more structural safety of the nuclear power plants against impact, the impact resistance for the 1% steel and 2% polyamide fiber reinforced concretes have been evaluated. For reactor containment building structures, it seem there is no impact resistance enhancement of fiber reinforced concrete applied to reactor containment building in the cases of impact velocity 150 m/sec considered in this study. However this results from the pre-stressing forces which introduce compressive stresses in concrete wall and dome section of reactor containment building. Nonetheless there may be benefits to apply fiber reinforced concrete to nuclear power plants. For double containment type reactor containment building, the outer structure is a reinforced concrete structure. The impact resistances for non pre-stressed cylindrical reactor containment buildings are enhanced by 23 to 47 % for 2 % polyamide fiber reinforced concretes and 1 % steel fiber reinforced concretes respectively. For other buildings such as auxiliary building, compound building and fuel storage building surrounding the reactor containment building, there are so many reinforced concrete walls which are anticipated some enhancements of impact resistance by using fiber reinforced concretes. And heavier or faster large civil aircraft impacts produce higher

  6. Steel fiber reinforced concrete behavior, modelling and design

    CERN Document Server

    Singh, Harvinder

    2017-01-01

    This book discusses design aspects of steel fiber-reinforced concrete (SFRC) members, including the behavior of the SFRC and its modeling. It also examines the effect of various parameters governing the response of SFRC members in detail. Unlike other publications available in the form of guidelines, which mainly describe design methods based on experimental results, it describes the basic concepts and principles of designing structural members using SFRC as a structural material, predominantly subjected to flexure and shear. Although applications to special structures, such as bridges, retaining walls, tanks and silos are not specifically covered, the fundamental design concepts remain the same and can easily be extended to these elements. It introduces the principles and related theories for predicting the role of steel fibers in reinforcing concrete members concisely and logically, and presents various material models to predict the response of SFRC members in detail. These are then gradually extended to d...

  7. Fiber breakage phenomena in long fiber reinforced plastic preparation

    International Nuclear Information System (INIS)

    Huang, Chao-Tsai; Tseng, Huan-Chang; Chang, Rong-Yeu; Vlcek, Jiri

    2015-01-01

    Due to the high demand of smart green, the lightweight technologies have become the driving force for the development of automotives and other industries in recent years. Among those technologies, using short and long fiber-reinforced plastics (FRP) to replace some metal components can reduce the weight of an automotive significantly. However, the microstructures of fibers inside plastic matrix are too complicated to manage and control during the injection molding through the screw, the runner, the gate, and then into the cavity. This study focuses on the fiber breakage phenomena during the screw plastification. Results show that fiber breakage is strongly dependent on screw design and operation. When the screw geometry changes, the fiber breakage could be larger even with lower compression ratio. (paper)

  8. Fracture morphology of carbon fiber reinforced plastic composite laminates

    Directory of Open Access Journals (Sweden)

    Vinod Srinivasa

    2010-09-01

    Full Text Available Carbon fiber reinforced plastic (CFRP composites have been extensively used in fabrication of primary structures for aerospace, automobile and other engineering applications. With continuous and widespread use of these composites in several advanced technology, the frequency of failures is likely to increase. Therefore, to establish the reasons for failures, the fracture modes should be understood thoroughly and unambiguously. In this paper, CFRP composite have been tested in tension, compression and flexural loadings; and microscopic study with the aid of Scanning Electron Microscope (SEM has been performed on failed (fractured composite surfaces to identify the principle features of failure. Efforts have been made in correlating the fracture surface characteristics to the failure mode. The micro-mechanics analysis of failure serves as a useful guide in selecting constituent materials and designing composites from the failure behavior point of view. Also, the local failure initiation results obtained here has been reliably extended to global failure prediction.

  9. Fiber-reinforced composites materials, manufacturing, and design

    CERN Document Server

    Mallick, P K

    2007-01-01

    The newly expanded and revised edition of Fiber-Reinforced Composites: Materials, Manufacturing, and Design presents the most up-to-date resource available on state-of-the-art composite materials. This book is unique in that it not only offers a current analysis of mechanics and properties, but also examines the latest advances in test methods, applications, manufacturing processes, and design aspects involving composites. This third edition presents thorough coverage of newly developed materials including nanocomposites. It also adds more emphasis on underlying theories, practical methods, and problem-solving skills employed in real-world applications of composite materials. Each chapter contains new examples drawn from diverse applications and additional problems to reinforce the practical relevance of key concepts. New in The Third Edition: Contains new sections on material substitution, cost analysis, nano- and natural fibers, fiber architecture, and carbon-carbon composites Provides a new chapter on poly...

  10. Neutron stress measurement of W-fiber reinforced Cu composite

    International Nuclear Information System (INIS)

    Nishida, M.; Hanabusa, T.; Ikeuchi, Y.; Minakawa, N.

    2003-01-01

    Stress measurement methods using neutron and X-ray diffraction were examined by comparing the surface stresses with internal stresses in the continuous tungsten-fiber reinforced copper-matrix composite. Surface stresses were measured by X-ray stress measurement with the sin 2 ψ method. Furthermore, the sin 2 ψ method and the most common triaxal measurement method using Hooke's equation were employed for internal stress measurement by neutron diffraction. On the other hand, microstress distributions developed by the difference in the thermal expansion coefficients between these two phases were calculated by FEM. The weighted average strains and stresses were compared with the experimental results. The FEM results agreed with the experimental results qualitatively and confirmed the importance of the triaxial stress analysis in the neutron stress measurement. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  11. Behavior of fiber reinforced metal laminates at high strain rate

    Science.gov (United States)

    Newaz, Golam; Sasso, Marco; Amodio, Dario; Mancini, Edoardo

    2018-05-01

    Carbon Fiber Reinforced Aluminum Laminate (CARALL) is a good system for energy absorption through plastic deformation in aluminum and micro-cracking in the composite layers. Moreover, CARALL FMLs also provide excellent impact resistance due to the presence of aluminum layer. The focus of this research is to characterize the CARALL behavior under dynamic conditions. High strain rate tests on sheet laminate samples have been carried out by means of direct Split Hopkinson Tension Bar. The sample geometry and the clamping system were optimized by FEM simulations. The clamping system has been designed and optimized in order reduce impedance disturbance due to the fasteners and to avoid the excessive plastic strain outside the gauge region of the samples.

  12. Chairside fabricated fiber-reinforced composite fixed partial denture

    Directory of Open Access Journals (Sweden)

    Sufyan Garoushi

    2007-01-01

    Full Text Available The advances in the materials and techniques for adhesive dentistry have allowed the development of non-invasive or minimally invasive approaches for replacing a missing tooth in those clinical situations when conservation of adjacent teeth is needed. Good mechanical and cosmetic/aesthetic properties of fiber-reinforced composite (FRC, with good bonding properties with composite resin cement and veneering composite are needed in FRC devices. Some recent studies have shown that adhesives of composite resins and luting cements allow diffusion of the adhesives to the FRC framework of the bridges. By this so-called interdiffusion bonding is formed [1]. FRC bridges can be made in dental laboratories or chairside. This article describes a clinical case of chairside (directly made FRC Bridge, which was used according to the principles of minimal invasive approach. Treatment was performed by Professor Vallittu from the University of Turku, Finland.

  13. Health monitoring technology for alumina-fiber-reinforced plastic

    International Nuclear Information System (INIS)

    Aoyama, Hiroshi; Watanabe, Hiroyuki; Terai, Motoaki

    1998-01-01

    Formally, we developed new load-support systems that consists of a biconical, alumina-fiber-reinforced plastic (ERP) structure for the superconducting magnet. Safe operation of the superconducting magnet will be jeopardized if the mechanical condition of the load-support system begins to degrade. One of the factors that evaluate the soundness of the superconducting magnet is the stiffness of the load-support system. Here, it is important to know the relation between the degradation of the stiffness and the growth of defects. For this purpose, firstly, a fatigue test of the load-support system was carried out, and the various defects (matrix cracking and delamination of FRP laminates) were observed during this fatigue testing. Finally, we proposed the application of two non-destructive-evaluation (NDE) methods for the health monitoring of alumina/epoxy load-support systems. (author)

  14. Carbon fiber reinforced hierarchical orthogrid stiffened cylinder: Fabrication and testing

    Science.gov (United States)

    Wu, Hao; Lai, Changlian; Sun, Fangfang; Li, Ming; Ji, Bin; Wei, Weiyi; Liu, Debo; Zhang, Xi; Fan, Hualin

    2018-04-01

    To get strong, stiff and light cylindrical shell, carbon fiber reinforced hierarchical orthogrid stiffened cylinders are designed and fabricated. The cylinder is stiffened by two-scale orthogrid. The primary orthogrid has thick and high ribs and contains several sub-orthogrid cells whose rib is much thinner and lower. The primary orthogrid stiffens the bending rigidity of the cylinder to resist the global instability while the sub-orthogrid stiffens the bending rigidity of the skin enclosed by the primary orthogrid to resist local buckling. The cylinder is fabricated by filament winding method based on a silicone rubber mandrel with hierarchical grooves. Axial compression tests are performed to reveal the failure modes. With hierarchical stiffeners, the cylinder fails at skin fracture and has high specific strength. The cylinder will fail at end crushing if the end of the cylinder is not thickened. Global instability and local buckling are well restricted by the hierarchical stiffeners.

  15. SYNTHESIS AND CHARACTERIZATION OF CANNABIS INDICA FIBER REINFORCED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Amar Singh Singha

    2011-04-01

    Full Text Available This paper reports on the synthesis of Cannabis indica fiber-reinforced composites using Urea-Resorcinol-Formaldehyde (URF as a novel matrix through compression molding technique. The polycondensation between urea, resorcinol, and formaldehyde in different molar ratios was applied to the synthesis of the URF polymer matrix. A thermosetting matrix based composite, reinforced with lignocellulose from Cannabis indica with different fiber loadings 10, 20, 30, 40, and 50% by weight, was obtained. The mechanical properties of randomly oriented intimately mixed fiber particle reinforced composites were determined. Effects of fiber loadings on mechanical properties such as tensile, compressive, flexural strength, and wear resistance were evaluated. Results showed that mechanical properties of URF resin matrix increased considerably when reinforced with particles of Cannabis indica fiber. Thermal (TGA/DTA/DTG and morphological studies (SEM of the resin, fiber and polymer composite thus synthesized were carried out.

  16. Applications of Fiber-Reinforced Polymers in Additive Manufacturing

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pedersen, David Bue; Tosello, Guido

    2017-01-01

    Additive manufacturing technologies are these years entering the market of functional final parts. Initial research has been performed targeting the integration of fibers into additive manufactured plastic composites. Major advantages, among others, are for example increased tensile strength...... and Young's modulus. Key challenges in the field, as of now, are proper fiber placement, fiber seizing, an increased knowledge in the used materials and how they are applied into engineering solutions through proper control of the additive manufacturing process. The aim of this research is the improved...... understanding of fiber-reinforcement in additive manufacturing in terms of production and application. Vat polymerization and material extrusion techniques for composite additive manufacturing were investigated with respect of increasing adhesion between the matrix material and the fibers. Process optimization...

  17. Micromechanisms of damage in unidirectional fiber reinforced composites

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Brøndsted, Povl

    2009-01-01

    strength of a composite at the pre-critical load, while the fibers with randomly distributed strengths lead to the higher strength of the composite at post-critical loads. In the case of randomly distributed fiber strengths, the damage growth in fibers seems to be almost independent from the crack length...... in the numerical experiments. The effect of the statistical variability of fiber strengths, viscosity of the polymer matrix as well as the interaction between the damage processes in matrix, fibers and interface are investigated numerically. It is demonstrated that fibers with constant strength ensure higher......Numerical micromechanical investigations of the mechanical behavior and damage evolution of glass fiber reinforced composites are presented. A program code for the automatic generation of 3D micromechanical unit cell models of composites with damageable elements is developed, and used...

  18. Puncture-Healing Thermoplastic Resin Carbon-Fiber-Reinforced Composites

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Siochi, Emilie J. (Inventor); Grimsley, Brian W. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor)

    2015-01-01

    A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

  19. Application of carbon fiber reinforced carbon composite to nuclear engineering

    International Nuclear Information System (INIS)

    Ishihara, Masahiro

    2003-01-01

    Carbon fiber reinforced carbon matrix composite (C/C composite) is thought to be one of promising structural materials with high temperature resistivity in the nuclear engineering field. In the high temperature gas-cooled reactors with gas outlet temperature maximum around 1000degC, high performance core internal structures, such as control rod sheath, core restraint mechanism, will be expected to achieve by the C/C composite application. Moreover, in the fusion reactors, plasma facing structures having high temperature with high neutron irradiation and particle collision will be expected to achieve by the C/C composite application. In this paper, current research and development studies of the C/C composite application on both reactors are reviewed and vista of the future on the C/C composite application is mentioned. (author)

  20. Robotic inspection of fiber reinforced composites using phased array UT

    Science.gov (United States)

    Stetson, Jeffrey T.; De Odorico, Walter

    2014-02-01

    Ultrasound is the current NDE method of choice to inspect large fiber reinforced airframe structures. Over the last 15 years Cartesian based scanning machines using conventional ultrasound techniques have been employed by all airframe OEMs and their top tier suppliers to perform these inspections. Technical advances in both computing power and commercially available, multi-axis robots now facilitate a new generation of scanning machines. These machines use multiple end effector tools taking full advantage of phased array ultrasound technologies yielding substantial improvements in inspection quality and productivity. This paper outlines the general architecture for these new robotic scanning systems as well as details the variety of ultrasonic techniques available for use with them including advances such as wide area phased array scanning and sound field adaptation for non-flat, non-parallel surfaces.

  1. [A maxillary premolar reconstruction with a glass fiber reinforced post].

    Science.gov (United States)

    Viţalariu, Anca Mihaela; Antohe, Magda; Bahrim, Delia; Tatarciuc, Monica

    2006-01-01

    This paper presents the case of a 37 years old female patient who needed a reconstruction of an endodontic treated' second maxillary premolar. The patient presented large areas of occlusal abrasion caused by bruxism, therefore the solution consisted of a reconstruction with a non-metallic post reinforced with glass fibers. In such cases, the excessive occlusal forces developed by bruxism can produce a radicular fracture if the tooth would be reconstructed with a rigid metallic post. The glass-fiber reinforced post has some important qualities, which render it more suitable in most clinical cases: it is easy to use; has the ability to bond with restorative resins; decreases the risk of tooth fracture and provides better esthetics.

  2. Acoustic emission from fiber reinforced plastic damaged hoop wrapped cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Akhtar, A.; Kung, D.; Westbrook, D.R.

    2000-03-01

    Metal lined continuous fiber reinforced plastic (FRP) hoop wrapped cylinders with axial cuts to the FRP were modeled mathematically and tested experimentally. Steel lined and aluminum alloy lined glass FRP vessels were subjected to acoustic emission tests (AE) and hydraulic burst tests. The burst pressure decreased monotonically with the length of the axial cut. Acoustic emission increased initially with a decrease in burst pressure, and attained a maximum at an intermediate level of damage to the FRP. However, acoustic emission decreased when the level of damage was higher and the burst pressure was lower. Implications of the findings are discussed in the context of the search for an acoustic emission test method to inspect periodically the vessels used for the storage of compressed gaseous fuels on natural gas vehicles (NGV) and hydrogen vehicles.

  3. Degradation behaviour of fiber reinforced plastic under electron beam irradiation

    International Nuclear Information System (INIS)

    Sonoda, Katsumi; Yamamoto, Yasushi; Hashimoto, Osamu

    1989-01-01

    Various mechanical properties of four kinds of glass fiber-reinforced plastics irradiated with electron beams were examined at three temperatures; room temperature, 123 K and 77 K. Dynamic viscoelastic properties were measured, and fractography by means of scanning electron microscopy was observed in order to clarify degradation behaviour. A considerable decrease in interlaminar shear strength (ILSS) at room temperature was observed above 60 MGy. On the other hand, the three-point bending strength at 77 K and the ILSS at 123 K decreased with increasing irradiation. Fractography reveals that the degradation of the interface layer between matrix resin and fiber plays an important role in the strength reduction at 123 K and 77 K. These findings suggest that the interface between matrix resin and fiber loses its bondability at 123 K arid 77 K after electron beam irradiation. (author)

  4. Performance of Sprayed Fiber Reinforced Polymer Strengthened Timber Beams

    Directory of Open Access Journals (Sweden)

    S. Talukdar

    2010-01-01

    Full Text Available A study was carried out to investigate the use of Sprayed Fiber Reinforced Polymer (SFRP for retrofit of timber beams. A total of 10-full scale specimens were tested. Two different timber preservatives and two different bonding agents were investigated. Strengthening was characterized using load deflection diagrams. Results indicate that it is possible to enhance load-carrying capacity and energy absorption characteristics using the technique of SFRP. Of the two types of preservatives investigated, the technique appears to be more effective for the case of creosote-treated specimens, where up to a 51% improvement in load-carrying capacity and a 460% increase in the energy absorption capacity were noted. Effectiveness of the bonding agent used was dependent on the type of preservative the specimen had been treated with.

  5. Glass fiber reinforced concrete for terrestrial photovoltaic arrays

    Science.gov (United States)

    Maxwell, H.

    1979-01-01

    The use of glass-fiber-reinforced concrete (GRC) as a low-cost structural substrate for terrestrial solar cell arrays is discussed. The properties and fabrication of glass-reinforced concrete structures are considered, and a preliminary design for a laminated solar cell assembly built on a GRC substrate is presented. A total cost for such a photovoltaic module, composed of a Korad acrylic plastic film front cover, an aluminum foil back cover, an ethylene/vinyl acetate pottant/adhesive and a cotton fabric electrical isolator in addition to the GRC substrate, of $9.42/sq m is projected, which is less than the $11.00/sq m cost goal set by the Department of Energy. Preliminary evaluations are concluded to have shown the design capabilities and cost effectiveness of GRC; however, its potential for automated mass production has yet to be evaluated.

  6. Tensile strength of woven yarn kenaf fiber reinforced polyester composites

    Directory of Open Access Journals (Sweden)

    A.E. Ismail

    2015-12-01

    Full Text Available This paper presents the tensile strength of woven kenaf fiber reinforced polyester composites. The as-received yarn kenaf fiber is weaved and then aligned into specific fiber orientations before it is hardened with polyester resin. The composite plates are shaped according to the standard geometry and uni-axially loaded in order to investigate the tensile responses. Two important parameters are studied such as fiber orientations and number of layers. According to the results, it is shown that fiber orientations greatly affected the ultimate tensile strength but it is not for modulus of elasticity for both types of layers. It is estimated that the reductions of both ultimate tensile strength and Young’s modulus are in the range of 27.7-30.9% and 2.4-3.7% respectively, if the inclined fibers are used with respect to the principal axis.

  7. Study on Mechanical Properties of Hybrid Fiber Reinforced Concrete

    Science.gov (United States)

    He, Dongqing; Wu, Min; Jie, Pengyu

    2017-12-01

    Several common high elastic modulus fibers (steel fibers, basalt fibers, polyvinyl alcohol fibers) and low elastic modulus fibers (polypropylene fiber) are incorporated into the concrete, and its cube compressive strength, splitting tensile strength and flexural strength are studied. The test result and analysis demonstrate that single fiber and hybrid fiber will improve the integrity of the concrete at failure. The mechanical properties of hybrid steel fiber-polypropylene fiber reinforced concrete are excellent, and the cube compressive strength, splitting tensile strength and flexural strength respectively increase than plain concrete by 6.4%, 3.7%, 11.4%. Doped single basalt fiber or polypropylene fiber and basalt fibers hybrid has little effect on the mechanical properties of concrete. Polyvinyl alcohol fiber and polypropylene fiber hybrid exhibit ‘negative confounding effect’ on concrete, its splitting tensile and flexural strength respectively are reduced by 17.8% and 12.9% than the single-doped polyvinyl alcohol fiber concrete.

  8. Corrosion and tribological properties of basalt fiber reinforced composite materials

    Science.gov (United States)

    Ha, Jin Cheol; Kim, Yun-Hae; Lee, Myeong-Hoon; Moon, Kyung-Man; Park, Se-Ho

    2015-03-01

    This experiment has examined the corrosion and tribological properties of basalt fiber reinforced composite materials. There were slight changes of weight after the occurring of corrosion based on time and H2SO4 concentration, but in general, the weight increased. It is assumed that this happens due to the basalt fiber precipitate. Prior to the corrosion, friction-wear behavior showed irregular patterns compared to metallic materials, and when it was compared with the behavior after the corrosion, the coefficient of friction was 2 to 3 times greater. The coefficient of friction of all test specimen ranged from 0.1 to 0.2. Such a result has proven that the basalt fiber, similar to the resin rubber, shows regular patterns regardless of time and H2SO4 concentration because of the space made between resins and reinforced materials.

  9. Nanorheology of regenerated silk fibroin solution

    Indian Academy of Sciences (India)

    Wintec

    material at micro and nano length scales, by video microscopy. We describe here .... to seal the slide, which was then inverted so that the cover slip was in contact ... processing time sequenced image frames of the embedded beads in a given ...

  10. Energy Absorption Capacity in Natural Fiber Reinforcement Composites Structures

    Directory of Open Access Journals (Sweden)

    Elías López-Alba

    2018-03-01

    Full Text Available The study of natural fiber reinforcement composite structures has focused the attention of the automobile industry due to the new regulation in relation to the recyclability and the reusability of the materials preserving and/or improving the mechanical characteristics. The influence of different parameters on the material behavior of natural fiber reinforced plastic structures has been investigated, showing the potential for transport application in energy absorbing structures. Two different woven fabrics (twill and hopsack made of flax fibers as well as a non-woven mat made of a mixture of hemp and kenaf fibers were employed as reinforcing materials. These reinforcing textiles were impregnated with both HD-PE (high-density polyethylen and PLA (polylactic acid matrix, using a continuous compression molding press. The impregnated semi-finished laminates (so-called organic sheets were thermoformed in a second step to half-tubes that were assembled through vibration-welding process to cylindric crash absorbers. The specimens were loaded by compression to determine the specific energy absorption capacity. Quasi-static test results were compared to dynamic test data obtained on a catapult arrangement. The differences on the specific energies absorption (SEA as a function of different parameters, such as the wall thickness, the weave material type, the reinforced textiles, and the matrix used, depending on the velocity rate application were quantified. In the case of quasi-static analysis it is observed a 20% increment in the SEA value when wove Hopsack fabric reinforcement is employed. No velocity rate influence from the material was observed on the SEA evaluation at higher speeds used to perform the experiments. The influence of the weave configuration (Hopsack seems to be more stable against buckling effects at low loading rates with 10% higher SEA values. An increase of SEA level of up to 72% for PLA matrix was observed when compared with HD

  11. Basalt fiber reinforced polymer composites: Processing and properties

    Science.gov (United States)

    Liu, Qiang

    A high efficiency rig was designed and built for in-plane permeability measurement of fabric materials. A new data derivation procedure to acquire the flow fluid pattern in the experiment was developed. The measurement results of the in-plane permeability for basalt twill 31 fabric material showed that a high correlation exists between the two principal permeability values for this fabric at 35% fiber volume fraction. This may be the most important scientific contribution made in this thesis. The results from radial measurements corresponded quite well with those from Unidirectional (UD) measurements, which is a well-established technique. No significant differences in mechanical properties were found between basalt fabric reinforced polymer composites and glass composites reinforced by a fabric of similar weave pattern. Aging results indicate that the interfacial region in basalt composites may be more vulnerable to environmental damage than that in glass composites. However, the basalt/epoxy interface may have been more durable than the glass/epoxy interface in tension-tension fatigue because the basalt composites have significantly longer fatigue life. In this thesis, chapter I reviews the literature on fiber reinforced polymer composites, with concentration on permeability measurement, mechanical properties and durability. Chapter II discusses the design of the new rig for in-plane permeability measurement, the new derivation procedure for monitoring of the fluid flow pattern, and the permeability measurement results. Chapter III compares the mechanical properties and durability between basalt fiber and glass fiber reinforced polymer composites. Lastly, chapter IV gives some suggestions and recommendations for future work.

  12. Nanofibrous nonmulberry silk/PVA scaffold for osteoinduction and osseointegration.

    Science.gov (United States)

    Bhattacharjee, Promita; Kundu, Banani; Naskar, Deboki; Maiti, Tapas K; Bhattacharya, Debasis; Kundu, Subhas C

    2015-05-01

    Poly-vinyl alcohol and nonmulberry tasar silk fibroin of Antheraea mylitta are blended to fabricate nanofibrous scaffolds for bone regeneration. Nanofibrous matrices are prepared by electrospinning the equal volume ratio blends of silk fibroin (2 and 4 wt%) with poly-vinyl alcohol solution (10 wt%) and designated as 2SF/PVA and 4SF/PVA, respectively with average nanofiber diameters of 177 ± 13 nm (2SF/PVA) and 193 ± 17 nm (4SF/PVA). Fourier transform infrared spectroscopy confirms retention of the secondary structure of fibroin in blends indicating the structural stability of neo-matrix. Both thermal stability and contact angle of the blends decrease with increasing fibroin percentage. Conversely, fibroin imparts mechanical stability to the blends; greater tensile strength is observed with increasing fibroin concentration. Blended scaffolds are biodegradable and support well the neo-bone matrix synthesis by human osteoblast like cells. The findings indicate the potentiality of nanofibrous scaffolds of nonmulberry fibroin as bone scaffolding material. © 2014 Wiley Periodicals, Inc.

  13. An axial distribution of seeding, proliferation, and osteogenic differentiation of MC3T3-E1 cells and rat bone marrow-derived mesenchymal stem cells across a 3D Thai silk fibroin/gelatin/hydroxyapatite scaffold in a perfusion bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Sinlapabodin, Salita; Amornsudthiwat, Phakdee; Damrongsakkul, Siriporn; Kanokpanont, Sorada, E-mail: sorada.k@chula.ac.th

    2016-01-01

    In cell culture, a perfusion bioreactor provides effective transportation of nutrients, oxygen, and waste removal to and from the core of the scaffold. In addition, it provides mechanical stimuli for enhancing osteogenic differentiation. In this study, we used an axial distribution of cell numbers, alkaline phosphatase (ALP) enzyme activity, and calcium content across 4 cross-sections of 10 mm thick scaffold, made of Thai silk fibroin (SF)/gelatin (G)/hydroxyapatite (HA), as a tool to evaluate the suitable perfusion flow rate. These evaluations cover all cellular developmental phases starting from seeding, to proliferation, and later osteogenic differentiation. Mouse pre-osteoblastic MC3T3-E1 cell lines were used as a cell model during seeding and proliferation. The bioreactor seeded scaffold provided more uniform cell distribution across the scaffold compared to centrifugal and agitation seeding, while the overall number of adhered cells from bioreactor seeding was slightly lower than agitation seeding. The dynamic culture using 1 ml/min perfusion flow rate (initial shear stress of 0.1 dyn/cm{sup 2}) enabled statistically higher MC3T3-E1 proliferation, ALP activity, and calcium deposition than those observed in the static-culturing condition. However, the perfusion flow rate of 1 ml/min seemed not to be enough for enhancing ALP expression across all sections of the scaffold. Rat bone marrow derived stromal cells (rMSC) were used in the detachment test and osteogenic differentiation. It was found that perfusion flow rate of 5 ml/min caused statistically higher cell detachment than that of 1 and 3 ml/min. The perfusion flow rate of 3 ml/min gave the highest rMSC osteogenic differentiation on a SF/G/HA scaffold than other flow rates, as observed from the significantly highest number of ALP enzyme activity and the calcium content without any significant cell growth. In addition, all of these parameters were evenly distributed across all scaffold sections. - Highlights

  14. 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)

  15. Design and analysis of coiled fiber reinforced soft pneumatic actuator.

    Science.gov (United States)

    Singh, Gaurav; Xiao, Chenzhang; Hsiao-Wecksler, Elizabeth T; Krishnan, Girish

    2018-04-18

    Fiber reinforced elastomeric enclosures (FREEs) are soft pneumatic actuators that can contract and generate forces upon pressurization. Typical engineering applications utilize FREEs in their straight cylindrical configuration and derive actuation displacement and forces from their ends. However, there are several instances in nature, such as an elephant trunk, snakes and grapevine tendrils, where a spiral configuration of muscle systems is used for gripping, thereby establishing a mechanical connection with uniform force distribution. Inspired by these examples, this paper investigates the constricting behavior of a contracting FREE actuator deployed in a spiral or coiled configuration around a cylindrical object. Force balance is used to model the blocked force of the FREE, which is then related to the constriction force using a string model. The modeling and experimental findings reveal an attenuation in the blocked force, and thus the constriction force caused by the coupling of peripheral contact forces acting in the spiral configuration. The usefulness of the coiled FREE configuration is demonstrated in a soft arm orthosis for crutch users that provides a constriction force around the forearm. This design minimizes injury risk by reducing wrist load and improving wrist posture.

  16. Fiber reinforced silicon-containing arylacetylene resin composites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available A silicon-containing arylacetylene resin (SAR, a poly(dimethylsilyleneethynylene phenyleneethynylene (PMSEPE, was synthesized. The PMSEPE is a solid resin at ambient temperature with a softening temperature about 60°C and soluble in some solvents like tetrahydrofuran. The melt viscosity of the PMSEPE resin is less than 1 Pa•s. The resin could cure at the temperature of lower than 200°C. Fiber reinforced PMSEPE composites were prepared from prepregs which were made by the impregnation of fibers in PMSEPE resin solution. The composites exhibit good mechanical properties at room temperature and 250°C. The observation on fracture surfaces of the composites reinforced by glass fibers and carbon fibers demonstrates that the adhesion between the fibers and resin is good. The results from an oxyacetylene flame test show that the composites have good ablation performance and XRD analyses indicate that SiC forms in the residues during the ablation of the composites.

  17. Performance of Lightweight Natural-Fiber Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Hardjasaputra Harianto

    2017-01-01

    Full Text Available Concrete, the most common construction material, has negligible tension capacity. However, a reinforcement material such as natural fibers, can be used to improve the tensile properties of concrete. This paper presents experiments conducted on Super Lightweight Concrete mixed with coconut fibers (SLNFRC. Coconut fibers are regarded as one of the toughest natural fibers to strengthen concrete. Coconut fiber reinforced composites have been considered as a sustainable construction material because the fibers are derived from waste. These wastes, which are available in large quantities in Asia, have to be extracted from the husk of coconut fruits and must pass a mechanical process before being added to a concrete mixture. The Super Lightweight Concrete was made by mixing concrete paste with foam agent that can reduce the overall weight of concrete up to 60% with compressive strength up to 6 MPa. The Super Lightweight Concrete is intended to be used for non-structural walls, as alternative conventional construction materials such as brick walls. The influence of coconut fibers content in increasing the flexural tensile strength of Super Lightweight Concrete was studied in this research. The fiber content studied include 0%, 0.1%, 0.175%, and 0.25% by weight of cement content. Sixteen specimens of SLNFRC mini beams of 60 mm x 60 mm x 300 mm were tested to failure to investigate their flexural strengths. The optimum percent fibers yielding higher tensile strength was found to be 0.175%

  18. Measurement of defects in carbon fiber reinforced polymer drilled

    Directory of Open Access Journals (Sweden)

    Pascual Víctor

    2017-01-01

    Full Text Available Increasingly, fiber-reinforced materials are more widely used because of their good mechanical properties. It is usual to join pieces of these materials through screws and rivets, for which it is necessary to make a hole in the piece, usually by drilling. One of the problems of use CFRP resides in the appearance of defects due to the machining. The main defect to be taken into account is the delamination. Delamination implies poor tolerance when assembling parts, reducing the structural integrity of the part, and areas with high wear, as a series of stresses arise when mounting the screws. Much has been published about delamination and the factors that influence its appearance, so we are not going to focus on it. The present study aims to quantify and measure the defects associated with the drilling of compounds reinforced with carbon fibers, in relation to the cutting parameters used in each case. For this purpose, an optical measurement system and a posterior digital image processing will be used through Deltec Vision software.

  19. Development of Abaca Fiber-reinforced Foamed Fly Ash Geopolymer

    Directory of Open Access Journals (Sweden)

    Janne Pauline S. Ngo

    2018-01-01

    Full Text Available The growing environmental and economic concerns have led to the need for more sustainable construction materials. The development of foamed geopolymer combines the benefit of reduced environmental footprint and attractive properties of geopolymer technology with foam concrete’s advantages of being lightweight, insulating and energy-saving. In this study, alkali-treated abaca fiber-reinforced geopolymer composites foamed with H2O2 were developed using fly ash as the geopolymer precursor. The effects of abaca fiber loading, foaming agent dosage, and curing temperature on mechanical strength were evaluated using Box-Behken design of experiment with three points replicated. Volumetric weight of samples ranged from 1966 kg/m3 to 2249 kg/m3. Measured compressive strength and flexural ranged from 19.56 MPa to 36.84 MPa, and 2.41 MPa to 6.25 MPa, respectively. Results suggest enhancement of compressive strength by abaca reinforcement and elevated temperature curing. Results, however, indicate a strong interaction between curing temperature and foaming agent dosage, which observably caused the composite’s compressive strength to decline when simultaneously set at high levels. Foaming agent dosage was the only factor detected to significantly affect flexural strength.

  20. Repair of reinforced concrete beams using carbon fiber reinforced polymer

    Directory of Open Access Journals (Sweden)

    Karzad Abdul Saboor

    2017-01-01

    Full Text Available This research paper is part of an ongoing research on the behaviour of Reinforced Concrete (RC beams retrofitted with Externally Bonded Carbon Fiber Reinforced Polymer (EB-CFRP. A total of 5 large-scale rectangular beams, previously damaged due to shear loading, were repaired and strengthened with EB-CFRP and tested in this study. The major cracks of the damaged beams were injected with epoxy and the beams were wrapped with 2 layers of EB-CFRP discrete strips with 100mm width and 150mm center to center spacing. The beams were instrumented and tested to failure under three points loading in simply supported configuration. The measured test parameters were the beams deflection, maximum load, and the strain in the FRP strips. The failure mode was also observed. The results showed that applying EB-FRP strips increased the shear strength significantly relative to the original shear capacity of the beam. The results demonstrate that the application of EB-FRP strips used in this study is an effective repair method that can be used to repair and strengthen damaged beams.

  1. Unsaturated and Saturated Permeabilities of Fiber Reinforcement: Critics and Suggestions

    Directory of Open Access Journals (Sweden)

    Chung Hae ePARK

    2015-04-01

    Full Text Available In general, permeability measurement results show a strong scattering according to the measurement method, the type of test fluid and the fluid injection condition, even though permeability is regarded as a unique property of porous medium. In particular, the discrepancy between the unsaturated and saturated permeabilities for the same fabric has been widely reported. In the literature, relative permeability has been adopted to model the unsaturated flow. This approach has some limits in the modeling of double-scale porosity medium. We address this issue of permeability measurement by rigorously examining the mass conservation condition. Finally, we identify that the pressure gradient is non-linear with positive curvature in the unsaturated flow and a misinterpretation of pressure gradient is the main reason for the difference between the saturated and unsaturated permeabilities of the same fiber reinforcement. We propose to use a fixed value of permeability and to modify the mass conservation equation if there are air voids which are entrapped inside the fiber tow. Finally, we also suggest some guidelines and future perspectives to obtain more consistent permeability measurement results.

  2. Anomaly detection of microstructural defects in continuous fiber reinforced composites

    Science.gov (United States)

    Bricker, Stephen; Simmons, J. P.; Przybyla, Craig; Hardie, Russell

    2015-03-01

    Ceramic matrix composites (CMC) with continuous fiber reinforcements have the potential to enable the next generation of high speed hypersonic vehicles and/or significant improvements in gas turbine engine performance due to their exhibited toughness when subjected to high mechanical loads at extreme temperatures (2200F+). Reinforced fiber composites (RFC) provide increased fracture toughness, crack growth resistance, and strength, though little is known about how stochastic variation and imperfections in the material effect material properties. In this work, tools are developed for quantifying anomalies within the microstructure at several scales. The detection and characterization of anomalous microstructure is a critical step in linking production techniques to properties, as well as in accurate material simulation and property prediction for the integrated computation materials engineering (ICME) of RFC based components. It is desired to find statistical outliers for any number of material characteristics such as fibers, fiber coatings, and pores. Here, fiber orientation, or `velocity', and `velocity' gradient are developed and examined for anomalous behavior. Categorizing anomalous behavior in the CMC is approached by multivariate Gaussian mixture modeling. A Gaussian mixture is employed to estimate the probability density function (PDF) of the features in question, and anomalies are classified by their likelihood of belonging to the statistical normal behavior for that feature.

  3. Flexural Cracking Behavior Of Steel Fiber Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Ashraf Abdalkader

    2017-08-01

    Full Text Available Steel fibers are added to concrete due to its ability to improve the tensile strength and control propagation of cracks in reinforced concrete members. Steel fiber reinforced concrete is made of cement fine water and coarse aggregate in addition to steel fibers. In this experimental work flexural cracking behavior of reinforced concrete beams contains different percentage of hooked-end steel fibers with length of 50 mm and equivalent diameter of 0.5 mm was studied. The beams were tested under third-point loading test at 28 days. First cracking load maximum crack width cracks number and load-deflection relations were investigated to evaluate the flexural cracking behavior of concrete beams with 34 MPa target mean strength. Workability wet density compressive and splitting tensile strength were also investigated. The results showed that the flexural crack width is significantly reduced with the addition of steel fibers. Fiber contents of 1.0 resulted in 81 reduction in maximum crack width compared to control concrete without fiber. The results also showed that the first cracking load and maximum load are increased with the addition of steel fibers.

  4. Acoustic emission of fire damaged fiber reinforced concrete

    Science.gov (United States)

    Mpalaskas, A. C.; Matikas, T. E.; Aggelis, D. G.

    2016-04-01

    The mechanical behavior of a fiber-reinforced concrete after extensive thermal damage is studied in this paper. Undulated steel fibers have been used for reinforcement. After being exposed to direct fire action at the temperature of 850°C, specimens were subjected to bending and compression in order to determine the loss of strength and stiffness in comparison to intact specimens and between the two types. The fire damage was assessed using nondestructive evaluation techniques, specifically ultrasonic pulse velocity (UPV) and acoustic emission (AE). Apart from the strong, well known, correlation of UPV to strength (both bending and compressive), AE parameters based mainly on the frequency and duration of the emitted signals after cracking events showed a similar or, in certain cases, better correlation with the mechanical parameters and temperature. This demonstrates the sensitivity of AE to the fracture incidents which eventually lead to failure of the material and it is encouraging for potential in-situ use of the technique, where it could provide indices with additional characterization capability concerning the mechanical performance of concrete after it subjected to fire.

  5. STUDY THE CREEP OF TUBULAR SHAPED FIBER REINFORCED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Najat J. Saleh

    2013-05-01

    Full Text Available Inpresent work tubular –shaped fiber reinforced composites were manufactured byusing two types of resins ( Epoxy and unsaturated polyester and separatelyreinforced with glass, carbon and kevlar-49 fibers (filament and woven roving,hybrid reinforcement composites of these fibers were also prepared. The fiberswere wet wound on a mandrel using a purposely designed winding machine,developed by modifying an ordinary lathe, in winding angle of 55° for filament. A creep test was made of either the fulltube or specimens taken from it. Creep was found to increase upon reinforcementin accordance to the rule of mixture and mainly decided by the type of singleor hybridized fibers. The creep behavior, showed that the observed strain tendsto appear much faster at higher temperature as compared with that exhibited atroom temperate. The creep rate also found to be depending on fiber type, matrixtype, and the fiber /matrix bonding. The creep energy calculated fromexperimental observations was found to exhibit highest value for hybridizedreinforcement.

  6. In vitro study of transverse strength of fiber reinforced composites.

    Science.gov (United States)

    Mosharraf, R; Hashemi, Z; Torkan, S

    2011-01-01

    Reinforcement with fiber is an effective method for considerable improvement in flexural properties of indirect composite resin restorations. The aim of this in-vitro study was to compare the transverse strength of composite resin bars reinforced with pre-impregnated and non-impregnated fibers. Thirty six bar type composite resin specimens (3×2×25 mm) were constructed in three groups. The first group was the control group (C) without any fiber reinforcement. The specimens in the second group (P) were reinforced with pre-impregnated fibers and the third group (N) with non-impregnated fibers. These specimens were tested by the three-point bending method to measure primary transverse strength. Data were statistically analyzed with one way ANOVA and Tukey's tests. There was a significant difference among the mean primary transverse strength in the three groups (Ptransverse strength (Pstudy, it was concluded that reinforcement with fiber considerably increased the transverse strength of composite resin specimens, but impregnation of the fiber used implemented no significant difference in the transverse strength of composite resin samples.

  7. Impact properties of aluminium - glass fiber reinforced plastics sandwich panels

    Directory of Open Access Journals (Sweden)

    Mathivanan Periasamy

    2012-06-01

    Full Text Available Aluminium - glass fiber reinforced plastics (GFRP sandwich panels are hybrid laminates consisting of GFRP bonded with thin aluminum sheets on either side. Such sandwich materials are increasingly used in airplane and automobile structures. Laminates with varying aluminium thickness fractions, fiber volume fractions and orientation in the layers of GFRP were fabricated by hand lay up method and evaluated for their impact performance by conducting drop weight tests under low velocity impacts. The impact energy required for initiating a crack in the outer aluminium layer as well as the energy required for perforation was recorded. The impact load-time history was also recorded to understand the failure behavior. The damage depth and the damage area were measured to evaluate the impact resistance. Optical photography and scanning electron micrographs were taken to visualize the crack and the damage zone. The bidirectional cross-ply hybrid laminate (CPHL has been found to exhibit better impact performance and damage resistance than the unidirectional hybrid laminate (UDHL. Increase in aluminium thickness fraction (Al tf and fiber volume fraction (Vf resulted in an increase in the impact energy required for cracking and perforation. On an overall basis, the sandwich panels exhibited better impact performance than the monolithic aluminium.

  8. Theory of the tensile actuation of fiber reinforced coiled muscles

    Science.gov (United States)

    Lamuta, C.; Messelot, S.; Tawfick, S.

    2018-05-01

    There is a strong need for compact artificial muscles capable of applying large contractile strokes and lift heavy weights. Coiled fibers recently emerged as attractive candidates for these purposes, owing to their simple construction and the possibility of their thermal, electrical and chemical actuation. An intuitive theoretical understanding of the mechanics of actuation of these muscles is essential for the enhancement of their performance and can pave the way for the development of new applications and technologies. In this paper, a complete theoretical model for the tensile actuation of fiber reinforced artificial muscles is presented and experimentally validated. The model demonstrates that all muscles made from the same material have a universal behavior, which can be described by a single master curve. It enables the systematic design and understanding of coiled muscles for specific performance owing to a comprehensive mathematical correlation among the geometry, materials properties, and actuation. Carbon fibers (CF)/polydimethylsiloxane coiled muscles are demonstrated as simple to fabricate yet powerful muscles owing to the availability of high strength CF. In addition to showing excellent agreement with the theoretical models, they can be actuated by joule heating or chemical swelling, lift up to 12 600 times their own weight, support up to 60 MPa of mechanical stress, provide tensile strokes higher than 25%, and a specific work up to 758 J kg‑1, the latter is more than 18 times higher than that of natural muscles.

  9. Probabilistic Flexural Fatigue in Plain and Fiber-Reinforced Concrete.

    Science.gov (United States)

    Ríos, José D; Cifuentes, Héctor; Yu, Rena C; Ruiz, Gonzalo

    2017-07-07

    The objective of this work is two-fold. First, we attempt to fit the experimental data on the flexural fatigue of plain and fiber-reinforced concrete with a probabilistic model (Saucedo, Yu, Medeiros, Zhang and Ruiz, Int. J. Fatigue, 2013, 48, 308-318). This model was validated for compressive fatigue at various loading frequencies, but not for flexural fatigue. Since the model is probabilistic, it is not necessarily related to the specific mechanism of fatigue damage, but rather generically explains the fatigue distribution in concrete (plain or reinforced with fibers) for damage under compression, tension or flexion. In this work, more than 100 series of flexural fatigue tests in the literature are fit with excellent results. Since the distribution of monotonic tests was not available in the majority of cases, a two-step procedure is established to estimate the model parameters based solely on fatigue tests. The coefficient of regression was more than 0.90 except for particular cases where not all tests were strictly performed under the same loading conditions, which confirms the applicability of the model to flexural fatigue data analysis. Moreover, the model parameters are closely related to fatigue performance, which demonstrates the predictive capacity of the model. For instance, the scale parameter is related to flexural strength, which improves with the addition of fibers. Similarly, fiber increases the scattering of fatigue life, which is reflected by the decreasing shape parameter.

  10. Fiber Reinforced Concrete (FRC) for High Rise Construction: Case Studies

    Science.gov (United States)

    Gharehbaghi, Koorosh; Chenery, Rhea

    2017-12-01

    Due to its material element, Fiber Reinforced Concrete (FRC) could be stronger than traditional Concrete. This is due to FRC internal material compounds and elements. Furthermore, FRC can also significantly improve flexural strength when compared to traditional Concrete. This improvement in flexural strength can be varied depending on the actual fibers used. Although not new, FRC is gradually gaining popularity in the construction industry, in particular for high rise structures. This is due to its flexural strength, especially for high seismic zones, as it will provide a better solution then reinforced Concrete. The main aim of this paper is to investigate the structural importance of FRC for the high rise construction. Although there has been numerous studies and literature in justifying the FRC for general construction; this paper will consider its use specifically for high rise construction. Moreover, this paper will closely investigate eight case studies from Australian and United States as a part of the FRC validation for high rise construction. In doing so, this paper will examine their Structural Health Monitoring (SHM) to determine their overall structural performance.

  11. New Fiber Reinforced Waterless Concrete for Extraterrestrial Structural Applications

    Science.gov (United States)

    Toutanji, H.; Tucker, D.; Ethridge, E.

    2005-01-01

    Commercial use of sulfur concrete on Earth is well established, particularly in corrosive, e.g., acid and salt, environments. Having found troilite (FeS) on the Moon raises the question of using extracted sulfur as a lunar construction mate: iii an attractive alternative to conventional concrete as it does not require water For the purpose of this paper it is assumed that lunar ore is mined, refined, and the raw sulfur processed with appropriate lunar regolith to form, for example, brick and beam elements. Glass fibers produced from regolith were used as a reinforcement to improve the mechanical properties of the sulfur concrete. Glass fibers and glass rebar were produced by melting the lunar regolith simulant. Lunar regolith stimulant was melted in a 25 cc Pt-Rh crucible in a Sybron Thermoline 46100 high temperature MoSi2 furnace at melting temperatures of 1450 to 1600G. The glass melt wets the ceramic rod and long continuous glass fibers were easily hand drawn. The glass fibers were immediately coated with a protective polymer to maintain the mechanical strength. The viability of sulfur concrete as a construction material for extraterrestrial application is presented. The mechanical properties of the glass fiber reinforced sulfur concrete were investigated.

  12. Repair of impact damaged utility poles with fiber reinforced polymers (FRP), phase II.

    Science.gov (United States)

    2015-06-01

    Vehicle collisions with steel or aluminum utility poles are common occurrences that yield substantial but often repairable : damage. This project investigates the use of a fiber-reinforced polymer (FRP) composite system for in situ repair that : mini...

  13. Use of Steel Fiber-Reinforced Rubberized Concrete in Cold Regions

    Science.gov (United States)

    2017-12-24

    This report documents and presents the use of steel fiber-reinforced rubberized concrete (SFRRC) in cold regions. Further investigation of SFRRC use was conducted with the wheel tracker rut and freeze-thaw laboratory testing procedures at the Univers...

  14. Rapid replacement of Tangier Island bridges including lightweight and durable fiber-reinforced polymer deck systems.

    Science.gov (United States)

    2009-01-01

    Fiber-reinforced polymer (FRP) composite cellular deck systems were used as new bridge decks on two replacement bridges on Tangier Island, Virginia. The most important characteristics of this application were reduced self-weight and increased durabil...

  15. Polyurethane foam infill for fiber-reinforced polymer (FRP) bridge deck panels.

    Science.gov (United States)

    2014-05-01

    Although still in their infancy, fiber-reinforced polymer (FRP) bridges have shown great promise in eliminating corrosion : concerns and meeting (or exceeding) FHWAs goal of 100-year life spans for bridges. While FRP bridges are cost-effective in ...

  16. Drastic Improvements in Bonding of Fiber Reinforced Multifunctional Composites, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Achievement of a dramatic increase in the bond strength in the composite/adhesive interfaces of existing fiber reinforced polymer (FRP) composite material joints and...

  17. Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.

    Science.gov (United States)

    Wu, Yankai; Li, Yanbin; Niu, Bin

    2014-01-01

    Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

  18. Improvement of the piezoelectric properties of glass fiber-reinforced epoxy composites by poling treatment

    International Nuclear Information System (INIS)

    Oh, S M; Hwang, H Y

    2013-01-01

    Recently, a new non-destructive method has been proposed for damage monitoring of glass fiber-reinforced polymer composite materials using the piezoelectric characteristics of a polymeric matrix. Several studies of the piezoelectric properties of unidirectional glass fiber epoxy composites and damage monitoring of double-cantilever beams have supported the claim that the piezoelectric method is feasible and powerful enough to monitor the damage of glass fiber epoxy composites. Generally, conventional piezoelectric materials have higher piezoelectric characteristics through poling treatment. In this work, we investigated the change of the piezoelectric properties of glass fiber-reinforced epoxy composites before and after poling treatment. The piezoelectric constants (d 33 ) of glass fiber-reinforced epoxy composites increased by more than 400%. Also, x-ray diffraction tests revealed that poling treatment changed the degree of crystallinity of the epoxy matrix, and this led to the improvement of the piezoelectric characteristics of glass fiber-reinforced epoxy composites. (paper)

  19. Fracture strength of fiber-reinforced surface-retained anterior cantilever restorations

    NARCIS (Netherlands)

    Oezcan, Mutlu; Kumbuloglu, Ovul; User, Atilla

    2008-01-01

    Purpose: This study compared the fracture strength of direct anterior cantilever fiber-reinforced composite (FRC) fixed partial dentures (FPD) reinforced with 3 types of E-glass fibers preimpregnated with either urethane tetramethacrylate, bisphenol glycidylmethacrylate/polymethyl methacrylate, or

  20. Operational factors influence on service life characteristics of structural carbon fiber-reinforced plastic

    OpenAIRE

    Борозенець, Григорій; Павлов, Віктор; Семак, Інна

    2013-01-01

    The nature of strength changing of aircraft structural carbon fiber-reinforced plastic under influence of water saturation after static preloading and mode changing of structural elements forming process pressure is considered.

  1. Carbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beams

    Science.gov (United States)

    2018-01-01

    Corrosion of reinforcing steel reduces life spans of bridges throughout the United States; therefore, using non-corroding carbon fiber reinforced polymer (CFRP) reinforcement is seen as a way to increase service life. The use of CFRP as the flexural ...

  2. Recycled Glass Fiber Reinforced Polymer Composites Incorporated in Mortar for Improved Mechanical Performance

    Science.gov (United States)

    2017-12-11

    Glass fiber reinforced polymer (GFRP) recycled from retired wind turbines was implemented in mortar as a volumetric replacement of sand during the two phases of this study. In Phase I, the mechanically refined GFRP particle sizes were sieved for four...

  3. Health monitoring of precast bridge deck panels reinforced with glass fiber reinforced polymer (GFRP) bars.

    Science.gov (United States)

    2012-03-01

    The present research project investigates monitoring concrete precast panels for bridge decks that are reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. Due to the lack of long term research on concrete members reinforced with GFRP bars, lo...

  4. Cracking and debonding of a thin fiber reinforced concrete overlay : research brief.

    Science.gov (United States)

    2017-03-01

    Experimental tests found that the tensile interfacial energy : increased with fiber-reinforcement. Also bond tests indicated : that interfacial fracture occurred through the overlay mixture and : was proportional to the number of fibers which interse...

  5. ON SHEAR BEHAVIOR OF STRUCTURAL ELEMENTS MADE OF STEEL FIBER REINFORCED CONCRETE

    OpenAIRE

    Cuenca Asensio, Estefanía

    2013-01-01

    Cuenca Asensio, E. (2012). ON SHEAR BEHAVIOR OF STRUCTURAL ELEMENTS MADE OF STEEL FIBER REINFORCED CONCRETE [Tesis doctoral no publicada]. Universitat Politècnica de València. doi:10.4995/Thesis/10251/18326. Palancia

  6. Effect of polyester fiber reinforcement on the mechanical properties of interim fixed partial dentures

    Directory of Open Access Journals (Sweden)

    N. Gopichander

    2015-10-01

    Conclusion: Within the limitations of this study, polyester fiber reinforcements improved the mechanical properties of heat-polymerized PMMA, cold-polymerized PMMA, and bis-acrylic provisional FPD materials.

  7. Low Cost Resin for Self-Healing High Temperature Fiber Reinforced Polymer Matrix Composites, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past few decades, the manufacturing processes and our knowledge base for predicting the bulk mechanical response of fiber reinforced composite materials has...

  8. A Review on Artificial Aging Behaviors of Fiber Reinforced Polymer-matrix Composites

    OpenAIRE

    Meng Jiangyan; Wang Yunying

    2016-01-01

    As is known, factors in climate environment such as hygrothermal effect and UV may have a negative effect on the mechanical properties of fiber reinforced polymer-matrix composites, resulting in their strength and stiffness degraded. In this review, we summarize all the recent studies on the artificial climate aging, hygrothermal aging, and thermal-oxidation aging of fiber reinforced polymer-matrix composites, as well as their artificial accelerated aging and natural aging. In addition, studi...

  9. State-of-the-art of fiber-reinforced polymers in additive manufacturing technologies

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pedersen, David Bue; Tosello, Guido

    2017-01-01

    Additive manufacturing technologies have received a lot of attention in recent years for their use in multiple materials such as metals, ceramics, and polymers. The aim of this review article is to analyze the technology of fiber-reinforced polymers and its implementation with additive...... manufacturing. This article reviews recent developments, ideas, and state-of-the-art technologies in this field. Moreover, it gives an overview of the materials currently available for fiber-reinforced material technology....

  10. Hybrid Fiber Layup and Fiber-Reinforced Polymeric Composites Produced Therefrom

    Science.gov (United States)

    Barnell, Thomas J. (Inventor); Garrigan, Sean P. (Inventor); Rauscher, Michael D. (Inventor); Dietsch, Benjamin A. (Inventor); Cupp, Gary N. (Inventor)

    2018-01-01

    Embodiments of a hybrid fiber layup used to form a fiber-reinforced polymeric composite, and a fiber-reinforced polymeric composite produced therefrom are disclosed. The hybrid fiber layup comprises one or more dry fiber strips and one or more prepreg fiber strips arranged side by side within each layer, wherein the prepreg fiber strips comprise fiber material impregnated with polymer resin and the dry fiber strips comprise fiber material without impregnated polymer resin.

  11. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

    OpenAIRE

    Petersen, Richard C.

    2011-01-01

    Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats reve...

  12. Preparation and characterization of silk/silica hybrid biomaterials by sol-gel crosslinking process

    Energy Technology Data Exchange (ETDEWEB)

    Hou Aiqin, E-mail: aiqinhou@dhu.edu.c [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, 3H, 2999 North Renmin Road, Songjiang, Shanghai 201620 (China); Chen Huawei [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, 3H, 2999 North Renmin Road, Songjiang, Shanghai 201620 (China)

    2010-03-15

    The silk/silica hybrid biomaterials are synthesized by sol-gel crosslinking process. The chemical and morphological structures of silk/silica hybrids are investigated with micro-FT-IR spectra, X-ray diffraction, SEM, AFM, and DSC. The results show that the crosslinking reactions among inorganic nano-particles, fibroin and 2,4,6-tri[(2-epihydrin-3-bimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-EBAC) take place during sol-gel process. The silk/silica hybrids form new molecular structures containing not only organic fibroin but also inorganic nano-silica particles. The inorganic particles are bounded to the fibroin through covalent bonds. The silk/silica hybrids can form excellent film with very even nanometer particles. The thermal properties of organic/inorganic hybrid are improved.

  13. Preparation and characterization of silk/silica hybrid biomaterials by sol-gel crosslinking process

    International Nuclear Information System (INIS)

    Hou Aiqin; Chen Huawei

    2010-01-01

    The silk/silica hybrid biomaterials are synthesized by sol-gel crosslinking process. The chemical and morphological structures of silk/silica hybrids are investigated with micro-FT-IR spectra, X-ray diffraction, SEM, AFM, and DSC. The results show that the crosslinking reactions among inorganic nano-particles, fibroin and 2,4,6-tri[(2-epihydrin-3-bimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-EBAC) take place during sol-gel process. The silk/silica hybrids form new molecular structures containing not only organic fibroin but also inorganic nano-silica particles. The inorganic particles are bounded to the fibroin through covalent bonds. The silk/silica hybrids can form excellent film with very even nanometer particles. The thermal properties of organic/inorganic hybrid are improved.

  14. 人脐带间充质干细胞与蚕丝蛋白支架构建组织工程脂肪的研究%Study on reconstruction of tissue engineering adipose with human umbilical cord mesenchymal stem cells and silk fibroin scaffolds

    Institute of Scientific and Technical Information of China (English)

    刘毅; 肖宏涛

    2011-01-01

    目的:将体外以人脐带间充质干细胞(hUCMSCs)与蚕丝蛋白支架初步构建的组织工程脂肪移植到大鼠体内,观察其演变过程.方法:hUCMSCs与蚕丝蛋白支架复合培养10天后,进行成脂诱导;6周后将其移植到Wistar大鼠后肢肌肉内,同时,以同体积支架材料作为对照;分别于移植后4周和8周取材,行油红0染色、HE染色以及扫描电镜观察.结果.hUCMSCs与蚕丝蛋白支架复合培养及成脂诱导6周后,见大量成脂样细胞生成,并与支架牢固粘附.移植4周,移植物体积略小,质稍硬,表面有透明薄膜形成,膜中分布新生血管网;油红0染色见支架内新生脂肪组织及细胞呈橙红色;HE染色显示支架网眼内有新生脂肪组织,并可见少量炎性细胞浸润;扫描电镜见支架网眼内有球形、表面光滑的脂肪细胞.移植8周,移植物体积进一步缩小,质变软,表面薄膜内血管网丰富;油红0染色见支架中着橙红色组织较前明显增多,部分呈片状融合;HE染色显示新生脂肪明显增多,仍有少量炎性细胞浸润;扫描电镜显示脂肪细胞较前增生明显.对照组同样可见炎性细胞浸润,未见新生脂肪组织生成,支架材料8周时较4周时降解更加明显.结论:随着时间推移,蚕丝蛋白支架网眼内脂肪细胞逐渐增多,支架材料在体内呈现逐步降解趋势,说明体内环境有利于组织工程化脂肪的进一步形成.同时,也提示支架材料在组织相容性方面尚存不足.%Objective To transplant the tissue engineering adipose reconstructed with human umbilical cord mesenchymal stem cells (hUCMSCs)and silk fibroin scaffolds in vitro into Wistar rats, and dynamically observe their changing. Methods hUCMSCs and silk fibroin scaffolds were compoundly cultured ten days, then induced them into adipose and continuely cultured. Six weeks later, those compound materials were transplanted into muscles in hind legs of Wistar rats, at the same time, the

  15. Characteristics of continuous unidirectional kenaf fiber reinforced epoxy composites

    International Nuclear Information System (INIS)

    Mahjoub, Reza; Yatim, Jamaludin Mohamad; Mohd Sam, Abdul Rahman; Raftari, Mehdi

    2014-01-01

    Highlights: • To show the potential of continuous kenaf fiber to use in bio-composite. • To introduce new method of hand lay-up for fabricating bio-fiber composite. • To characterize the properties of kenaf fiber epoxy composite. • Morphology of the fracture area by using of SEM. • To use analytical method to predict the bio-composite properties. - Abstract: Kenaf fibers generally has some advantages such as eco-friendly, biodegradability, renewable nature and lighter than synthetic fibers. The aims of the study are to characterize and evaluate the physical and mechanical properties of continuous unidirectional kenaf fiber epoxy composites with various fiber volume fractions. The composites materials and sampling were prepared in the laboratory by using the hand lay-up method with a proper fabricating procedure and quality control. Samples were prepared based on ASTM: D3039-08 for tensile test and the scanning electron microscopy (SEM) was employed for microstructure analysis to observe the failure mechanisms in the fracture planes. A total of 40 samples were tested for the study. Results from the study showed that the rule of mixture (ROM) analytical model has a close agreement to predict the physical and tensile properties of unidirectional kenaf fiber reinforced epoxy composites. It was also observed that the tensile strength, tensile modulus, ultimate strain and Poisson’s ratio of 40% fiber volume content of unidirectional kenaf fiber epoxy composite were 164 MPa, 18150 MPa, 0.9% and 0.32, respectively. Due to the test results, increasing the fiber volume fraction in the composite caused the increment in the tensile modulus and reduction in the ultimate tensile strain of composite

  16. Mid-IR laser ultrasonic testing for fiber reinforced plastics

    Science.gov (United States)

    Kusano, Masahiro; Hatano, Hideki; Oguchi, Kanae; Yamawaki, Hisashi; Watanabe, Makoto; Enoki, Manabu

    2018-04-01

    Ultrasonic testing is the most common method to detect defects in materials and evaluate their sizes and locations. Since piezo-electric transducers are manually handled from point to point, it takes more costs for huge products such as airplanes. Laser ultrasonic testing (LUT) is a breakthrough technique. A pulsed laser generates ultrasonic waves on a material surface due to thermoelastic effect or ablation. The ultrasonic waves can be detected by another laser with an interferometer. Thus, LUT can realize instantaneous inspection without contacting a sample. A pulse laser with around 3.2 μm wavelength (in the mid-IR range) is more suitable to generate ultrasonic waves for fiber reinforced plastics (FRPs) because the light is well absorbed by the polymeric matrix. On the other hand, such a laser is not available in the market. In order to emit the mid-IR laser pulse, we came up with the application of an optical parametric oscillator and developed an efficient wavelength conversion device by pumping a compact Nd:YAG solid-state laser. Our mid-IR LUT system is most suitable for inspection of FRPs. The signal-to-noise ratio of ultrasonic waves generated by the mid-IR laser is higher than that by the Nd:YAG laser. The purpose of the present study is to evaluate the performance of the mid-IR LUT system in reflection mode. We investigated the effects of the material properties and the laser properties on the generated ultrasonic waves. In addition, C-scan images by the system were also presented.

  17. 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.

  18. Flexural strength using Steel Plate, Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) on reinforced concrete beam in building technology

    Science.gov (United States)

    Tarigan, Johannes; Patra, Fadel Muhammad; Sitorus, Torang

    2018-03-01

    Reinforced concrete structures are very commonly used in buildings because they are cheaper than the steel structures. But in reality, many concrete structures are damaged, so there are several ways to overcome this problem, by providing reinforcement with Fiber Reinforced Polymer (FRP) and reinforcement with steel plates. Each type of reinforcements has its advantages and disadvantages. In this study, researchers discuss the comparison between flexural strength of reinforced concrete beam using steel plates and Fiber Reinforced Polymer (FRP). In this case, the researchers use Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) as external reinforcements. The dimension of the beams is 15 x 25 cm with the length of 320 cm. Based on the analytical results, the strength of the beam with CFRP is 1.991 times its initial, GFRP is 1.877 times while with the steel plate is 1.646 times. Based on test results, the strength of the beam with CFRP is 1.444 times its initial, GFRP is 1.333 times while the steel plate is 1.167 times. Based on these test results, the authors conclude that beam with CFRP is the best choice for external reinforcement in building technology than the others.

  19. 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.

  20. 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

  1. Dextrose modified flexible tasar and muga fibroin films for wound healing applications

    International Nuclear Information System (INIS)

    Srivastava, Chandra Mohan; Purwar, Roli; Gupta, Anuradha; Sharma, Deepak

    2017-01-01

    This paper is focused on preparation and characterization of regenerated muga and tasar fibroin flexible films from cocoon using ionic liquid. These flexible muga and tasar fibroin films were prepared by incorporating dextrose (5 to 15% w/w) as plasticizer. The mechanical, thermal, physical, morphological and biological properties of dextrose plasticized muga and tasar fibroin films were characterized. These plasticized films showed higher elongation at break as well as water holding capacity as compared to the un-plasticized films. The surface roughness and water absorbance capacity of the dextrose plasticized films were higher than un-plasticized films, which results in improved adherence and proliferation of L929 fibroblast cells. Gentamicin loaded plasticized muga and tasar fibroin films showed slightly higher rate of release as compared to un-plasticized films. The biodegradability of dextrose plasticized films was significantly higher as compared to their respective counterpart. The regeneration of flexible muga and tasar silk fibroin films pave the way to expand potential use of non-mulberry in the field of biomedical such as wound dressing. - Highlights: • Cocoon extracted muga and tasar fibroin have regenerated as flexible films. • Dextrose acts as plasticizer in muga and tasar fibroin films. • Films show good mechanical integrity, water absorption, biocompatibility over the un-plasticized films. • These flexible films are found to be promising candidates for wound healing.

  2. Dextrose modified flexible tasar and muga fibroin films for wound healing applications

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Chandra Mohan [Department of Applied Chemistry and Polymer Technology, Delhi Technological University, Shahbad, Daulatpur Bawana Road, Delhi 110042 (India); Purwar, Roli, E-mail: roli.purwar@dce.edu [Department of Applied Chemistry and Polymer Technology, Delhi Technological University, Shahbad, Daulatpur Bawana Road, Delhi 110042 (India); Gupta, Anuradha; Sharma, Deepak [Department of Pharmaceutics, Central Drug Research Institute, Lucknow 226031 (India)

    2017-06-01

    This paper is focused on preparation and characterization of regenerated muga and tasar fibroin flexible films from cocoon using ionic liquid. These flexible muga and tasar fibroin films were prepared by incorporating dextrose (5 to 15% w/w) as plasticizer. The mechanical, thermal, physical, morphological and biological properties of dextrose plasticized muga and tasar fibroin films were characterized. These plasticized films showed higher elongation at break as well as water holding capacity as compared to the un-plasticized films. The surface roughness and water absorbance capacity of the dextrose plasticized films were higher than un-plasticized films, which results in improved adherence and proliferation of L929 fibroblast cells. Gentamicin loaded plasticized muga and tasar fibroin films showed slightly higher rate of release as compared to un-plasticized films. The biodegradability of dextrose plasticized films was significantly higher as compared to their respective counterpart. The regeneration of flexible muga and tasar silk fibroin films pave the way to expand potential use of non-mulberry in the field of biomedical such as wound dressing. - Highlights: • Cocoon extracted muga and tasar fibroin have regenerated as flexible films. • Dextrose acts as plasticizer in muga and tasar fibroin films. • Films show good mechanical integrity, water absorption, biocompatibility over the un-plasticized films. • These flexible films are found to be promising candidates for wound healing.

  3. Fiber-Reinforced Epoxy Composites and Methods of Making Same Without the Use of Oven or Autoclave

    Science.gov (United States)

    Barnell, Thomas J. (Inventor); Rauscher, Michael D. (Inventor); Stienecker, Rick D. (Inventor); Nickerson, David M. (Inventor); Tong, Tat H. (Inventor)

    2016-01-01

    Method embodiments for producing a fiber-reinforced epoxy composite comprise providing a mold defining a shape for a composite, applying a fiber reinforcement over the mold, covering the mold and fiber reinforcement thereon in a vacuum enclosure, performing a vacuum on the vacuum enclosure to produce a pressure gradient, insulating at least a portion of the vacuum enclosure with thermal insulation, infusing the fiber reinforcement with a reactive mixture of uncured epoxy resin and curing agent under vacuum conditions, wherein the reactive mixture of uncured epoxy resin and curing agent generates exothermic heat, and producing the fiber-reinforced epoxy composite having a glass transition temperature of at least about 100.degree. C. by curing the fiber reinforcement infused with the reactive mixture of uncured epoxy resin and curing agent by utilizing the exothermically generated heat, wherein the curing is conducted inside the thermally insulated vacuum enclosure without utilization of an external heat source or an external radiation source.

  4. 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

  5. Stabilized fiber-reinforced pavement base course with recycled aggregate

    Science.gov (United States)

    Sobhan, Khaled

    's assumptions for rigid pavements), which has been found to explain reasonably well the field behavior of unreinforced and fiber-reinforced concrete slabs on grade. Finally, a preliminary cost analysis demonstrated that the use of stabilized recycled aggregate instead of a standard crushed stone base course can result in a meaningful economic savings.

  6. On Healable Polymers and Fiber-Reinforced Composites

    Science.gov (United States)

    Nielsen, Christian Eric

    Polymeric materials capable of healing damage would be valuable in structural applications where access for repair is limited. Approaches to creating such materials are reviewed, with the present work focusing on polymers with thermally reversible covalent cross-links. These special cross-links are Diels-Alder (DA) adducts, which can be separated and re-formed, enabling healing of mechanical damage at the molecular level. Several DA-based polymers, including 2MEP4FS, are mechanically and thermally characterized. The polymerization reaction of 2MEP4FS is modeled and the number of established DA adducts is associated with the glass transition temperature of the polymer. The models are applied to concentric cylinder rotational measurements of 2MEP4FS prepolymer at room and elevated temperatures to describe the viscosity as a function of time, temperature, and conversion. Mechanical damage including cracks and scratches are imparted in cured polymer samples and subsequently healed. Damage due to high temperature thermal degradation is observed to not be reversible. The ability to repair damage without flowing polymer chains makes DA-based healable polymers particularly well-suited for crack healing. The double cleavage drilled compression (DCDC) fracture test is investigated as a useful method of creating and incrementally growing cracks in a sample. The effect of sample geometry on the fracture behavior is experimentally and computationally studied. Computational and empirical models are developed to estimate critical stress intensity factors from DCDC results. Glass and carbon fiber-reinforced composites are fabricated with 2MEP4FS as the matrix material. A prepreg process is developed that uses temperature to control the polymerization rate of the monomers and produce homogeneous prepolymer for integration with a layer of unidirectional fiber. Multiple prepreg layers are laminated to form multi-layered cross-ply healable composites, which are characterized in

  7. 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

  8. Effectiveness of Fiber Reinforcement on the Mechanical Properties and Shrinkage Cracking of Recycled Fine Aggregate Concrete

    Science.gov (United States)

    Nam, Jeongsoo; Kim, Gyuyong; Yoo, Jaechul; Choe, Gyeongcheol; Kim, Hongseop; Choi, Hyeonggil; Kim, Youngduck

    2016-01-01

    This paper presents an experimental study conducted to investigate the effect of fiber reinforcement on the mechanical properties and shrinkage cracking of recycled fine aggregate concrete (RFAC) with two types of fiber—polyvinyl alcohol (PVA) and nylon. A small fiber volume fraction, such as 0.05% or 0.1%, in RFAC with polyvinyl alcohol or nylon fibers was used for optimum efficiency in minimum quantity. Additionally, to make a comparative evaluation of the mechanical properties and shrinkage cracking, we examined natural fine aggregate concrete as well. The test results revealed that the addition of fibers and fine aggregates plays an important role in improving the mechanical performance of the investigated concrete specimens as well as controlling their cracking behavior. The mechanical properties such as compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced RFAC were slightly better than those of non-fiber-reinforced RFAC. The shrinkage cracking behavior was examined using plat-ring-type and slab-type tests. The fiber-reinforced RFAC showed a greater reduction in the surface cracks than non-fiber-reinforced concrete. The addition of fibers at a small volume fraction in RFAC is more effective for drying shrinkage cracks than for improving mechanical performance. PMID:28773256

  9. Primary Manufacturing Processes for Fiber Reinforced Composites: History, Development & Future Research Trends

    Science.gov (United States)

    Tapan Bhatt, Alpa; Gohil, Piyush P.; Chaudhary, Vijaykumar

    2018-03-01

    Composite Materials are becoming more popular gradually replacing traditional material with extra strength, lighter weight and superior property. The world is exploring use of fiber reinforced composites in all application which includes air, land and water transport, construction industry, toys, instrumentation, medicine and the list is endless. Based on application and reinforcement used, there are many ways to manufactures parts with fiber reinforced composites. In this paper various manufacturing processes have been discussed at length, to make fiber reinforced composites components. The authors have endeavored to include all the processes available recently in composite industry. Paper first highlights history of fiber reinforced composites manufacturing, and then the comparison of different manufacturing process to build composites have been discussed, to give clear understanding on, which process should be selected, based on reinforcement, matrix and application. All though, there are several advantages to use such fiber reinforcement composites, still industries have not grown at par and there is a lot of scope to improve these industries. At last, where India stands today, what are the challenges in market has been highlighted and future market and research trend of exploring such composite industries have been discussed. This work is carried out as a part of research project sanctioned by GUJCOST, Gandhinagar.

  10. Use of Fiber-Reinforced Cements in Masonry Construction and Structural Rehabilitation

    Directory of Open Access Journals (Sweden)

    Ece Erdogmus

    2015-02-01

    Full Text Available The use of fiber reinforcement in traditional concrete mixes has been extensively studied and has been slowly finding its regular use in practice. In contrast, opportunities for the use of fibers in masonry applications and structural rehabilitation projects (masonry and concrete structures have not been as deeply investigated, where the base matrix may be a weaker cementitious mixture. This paper will summarize the findings of the author’s research over the past 10 years in these particular applications of fiber reinforced cements (FRC. For masonry, considering both mortar and mortar-unit bond characteristics, a 0.5% volume fraction of micro fibers in type N Portland cement lime mortar appear to be a viable recipe for most masonry joint applications both for clay and concrete units. In general, clay units perform better with high water content fiber reinforced mortar (FRM while concrete masonry units (CMUs perform better with drier mixtures, so 130% and 110% flow rates should be targeted, respectively. For earth block masonry applications, fibers’ benefits are observed in improving local damage and water pressure resistance. The FRC retrofit technique proposed for the rehabilitation of reinforced concrete two-way slabs has exceeded expectations in terms of capacity increase for a relatively low cost in comparison to the common but expensive fiber reinforced polymer applications. For all of these applications of fiber-reinforced cements, further research with larger data pools would lead to further optimization of fiber type, size, and amount.

  11. Influence of cellulose fibers on structure and properties of fiber reinforced foam concrete

    Directory of Open Access Journals (Sweden)

    Fedorov Valeriy

    2018-01-01

    Full Text Available One of the promising means of foamed concrete quality improvement is micro-reinforcement by adding synthetic and mineral fibers to the base mix. This research is the first to investigate peculiarities of using recycled cellulose fiber extracted from waste paper for obtaining fiber reinforced foam concrete. The paper presents results of experimental research on the influence of cellulose fibers on structure and properties of fiber reinforced foam concrete by using methods of chemical analysis and scanning electron microscopy. The research determines peculiarities of new formations appearance and densification of binder hydration products in the contact zone between fiber and cement matrix, which boost mechanical strength of fiber reinforced foam concrete. Physico-mechanical properties of fiber reinforced foam concrete were defined depending on the amount of recycled cellulose fiber added to the base mix. It was found that the use of recycled cellulose fibers allows obtaining structural thermal insulating fiber reinforced foam concretes of non-autoclaved hardening of brand D600 with regard to mean density with the following improved properties: compressive strength increased by 35% compared to basic samples, higher stability of foamed concrete mix and decreased shrinkage deformation.

  12. Effectiveness of Fiber Reinforcement on the Mechanical Properties and Shrinkage Cracking of Recycled Fine Aggregate Concrete.

    Science.gov (United States)

    Nam, Jeongsoo; Kim, Gyuyong; Yoo, Jaechul; Choe, Gyeongcheol; Kim, Hongseop; Choi, Hyeonggil; Kim, Youngduck

    2016-02-26

    This paper presents an experimental study conducted to investigate the effect of fiber reinforcement on the mechanical properties and shrinkage cracking of recycled fine aggregate concrete (RFAC) with two types of fiber-polyvinyl alcohol (PVA) and nylon.