WorldWideScience

Sample records for hfip-derived silk scaffolds

  1. Spider Silk For Future Scaffolds

    OpenAIRE

    Bringhurst, Heidi; Decker, R.; Frisby, S.; Tucker, C.

    2014-01-01

    Spider silk, an ancient biomaterial, has many qualities worth replicating. With the use of genetic modification, relatively large amounts of the spider silk protein have been produced through goat milk. With access to this protein we have worked to create spider silk films and hydrogels. Through chemical and mechanical means, we are discovering treatments that maximize cell growth and cell attachment on spider silk films and hydrogels.

  2. Spider Silk For Future Scaffolds

    OpenAIRE

    Bringhurst, Heidi; Decker, R.; Frisby, S.; Tucker, C

    2014-01-01

    Spider silk, an ancient biomaterial, has many qualities worth replicating. With the use of genetic modification, relatively large amounts of the spider silk protein have been produced through goat milk. With access to this protein we have worked to create spider silk films and hydrogels. Through chemical and mechanical means, we are discovering treatments that maximize cell growth and cell attachment on spider silk films and hydrogels.

  3. Cytocompatibility of a silk fibroin tubular scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiannan, E-mail: wangjn@suda.edu.cn; 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.

  4. Silk scaffolds with tunable mechanical capability for cell differentiation.

    Science.gov (United States)

    Bai, Shumeng; Han, Hongyan; Huang, Xiaowei; Xu, Weian; Kaplan, David L; Zhu, Hesun; Lu, Qiang

    2015-07-01

    Bombyx mori silk fibroin is a promising biomaterial for tissue regeneration and is usually considered an "inert" material with respect to actively regulating cell differentiation due to few specific cell signaling peptide domains in the primary sequence and the generally stiffer mechanical properties due to crystalline content formed in processing. In the present study, silk fibroin porous 3D scaffolds with nanostructures and tunable stiffness were generated via a silk fibroin nanofiber-assisted lyophilization process. The silk fibroin nanofibers with high β-sheet content were added into the silk fibroin solutions to modulate the self-assembly, and to directly induce water-insoluble scaffold formation after lyophilization. Unlike previously reported silk fibroin scaffold formation processes, these new scaffolds had lower overall β-sheet content and softer mechanical properties for improved cell compatibility. The scaffold stiffness could be further tuned to match soft tissue mechanical properties, which resulted in different differentiation outcomes with rat bone marrow-derived mesenchymal stem cells toward myogenic and endothelial cells, respectively. Therefore, these silk fibroin scaffolds regulate cell differentiation outcomes due to their mechanical features.

  5. Silk porous scaffolds with nanofibrous microstructures and tunable properties.

    Science.gov (United States)

    Lu, Guozhong; Liu, Shanshan; Lin, Shasha; Kaplan, David L; Lu, Qiang

    2014-08-01

    Scaffold biomaterials derived from silk fibroin have been widely used in tissue engineering. However, mimicking the nanofibrous structures of the extracellular matrix (ECM) for achieving better biocompatibility remains a challenge. Here, we design a mild self-assembly approach to prepare nanofibrous scaffolds from silk fibroin solution. Silk nanofibers were self-assembled by slowly concentrating process in aqueous solution without any cross-linker or toxic solvent and then were further fabricated into porous scaffolds with pore size of about 200-250μm through lyophilization, mimicking nano and micro structures of ECM. Gradient water/methanol annealing treatments were used to control the secondary structures, mechanical properties, and degradation behaviors of the scaffolds, which would be critical for different tissue regeneration applications. With salt-leached silk scaffold as control, the ECM-mimetic scaffolds with different secondary structures were used to culture the amniotic fluid-derived stem cells in vitro to confirm their biocompatibility. All the ECM-mimetic scaffolds with different secondary structures represented better cell growth and proliferation compared to the salt-leached scaffold, confirming the critical influence of ECM-mimetic structure on biocompatibility. Although further studies such as cell differentiation behaviours are still necessary for clarifying the influence of microstructures and secondary conformational compositions, our study provides promising scaffold candidate that is suitable for different tissue regenerations.

  6. Carbon nanotubes on a spider silk scaffold

    Science.gov (United States)

    Steven, Eden; Saleh, Wasan R.; Lebedev, Victor; Acquah, Steve F. A.; Laukhin, Vladimir; Alamo, Rufina G.; Brooks, James S.

    2013-09-01

    Understanding the compatibility between spider silk and conducting materials is essential to advance the use of spider silk in electronic applications. Spider silk is tough, but becomes soft when exposed to water. Here we report a strong affinity of amine-functionalised multi-walled carbon nanotubes for spider silk, with coating assisted by a water and mechanical shear method. The nanotubes adhere uniformly and bond to the silk fibre surface to produce tough, custom-shaped, flexible and electrically conducting fibres after drying and contraction. The conductivity of coated silk fibres is reversibly sensitive to strain and humidity, leading to proof-of-concept sensor and actuator demonstrations.

  7. Fabrication and Mechanical Characterization of Hydrogel Infused Network Silk Scaffolds

    Science.gov (United States)

    Kundanati, Lakshminath; Singh, Saket K.; Mandal, Biman B.; Murthy, Tejas G.; Gundiah, Namrata; Pugno, Nicola M.

    2016-01-01

    Development and characterization of porous scaffolds for tissue engineering and regenerative medicine is of great importance. In recent times, silk scaffolds were developed and successfully tested in tissue engineering and drug release applications. We developed a novel composite scaffold by mechanical infusion of silk hydrogel matrix into a highly porous network silk scaffold. The mechanical behaviour of these scaffolds was thoroughly examined for their possible use in load bearing applications. Firstly, unconfined compression experiments show that the denser composite scaffolds displayed significant enhancement in the elastic modulus as compared to either of the components. This effect was examined and further explained with the help of foam mechanics principles. Secondly, results from confined compression experiments that resemble loading of cartilage in confinement, showed nonlinear material responses for all scaffolds. Finally, the confined creep experiments were performed to calculate the hydraulic permeability of the scaffolds using soil mechanics principles. Our results show that composite scaffolds with some modifications can be a potential candidate for use of cartilage like applications. We hope such approaches help in developing novel scaffolds for tissue engineering by providing an understanding of the mechanics and can further be used to develop graded scaffolds by targeted infusion in specific regions. PMID:27681725

  8. Fabrication and Mechanical Characterization of Hydrogel Infused Network Silk Scaffolds

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    Lakshminath Kundanati

    2016-09-01

    Full Text Available Development and characterization of porous scaffolds for tissue engineering and regenerative medicine is of great importance. In recent times, silk scaffolds were developed and successfully tested in tissue engineering and drug release applications. We developed a novel composite scaffold by mechanical infusion of silk hydrogel matrix into a highly porous network silk scaffold. The mechanical behaviour of these scaffolds was thoroughly examined for their possible use in load bearing applications. Firstly, unconfined compression experiments show that the denser composite scaffolds displayed significant enhancement in the elastic modulus as compared to either of the components. This effect was examined and further explained with the help of foam mechanics principles. Secondly, results from confined compression experiments that resemble loading of cartilage in confinement, showed nonlinear material responses for all scaffolds. Finally, the confined creep experiments were performed to calculate the hydraulic permeability of the scaffolds using soil mechanics principles. Our results show that composite scaffolds with some modifications can be a potential candidate for use of cartilage like applications. We hope such approaches help in developing novel scaffolds for tissue engineering by providing an understanding of the mechanics and can further be used to develop graded scaffolds by targeted infusion in specific regions.

  9. Preparation and cytocompatibility of silk fibroin /chitosan scaffolds

    Institute of Scientific and Technical Information of China (English)

    Zhen-ding SHE; Wei-qiang LIU; Qing-ling FENG

    2009-01-01

    One challenge in soft tissue engineering is to find an applicable scaffold, not only having suitable mechanical properties, porous structures, and biodegradable properties, but also being abundant in active groups and having good biocompatibility. In this study, a threedimensional silk fibroin/chitosan (SFCS) scaffold was successfully prepared with interconnected porous structure, excellent hydrophilicity, and proper mechanical properties. Compared with polylactic glycolic acid (PLGA) scaffold, the SFCS scaffold further facilitated the growth of HepG2 cells (human hepatoma cell line). Keeping the good cytocompatibility and combining the advantages of both fibroin and chitosan, the SFCS scaffold should be a prominent candidate for soft tissue engineering, for example, liver.

  10. 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.

  11. 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.

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

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    Stanley Chung

    2016-07-01

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

  13. 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.

  14. Fabrication and characterization of regenerated silk scaffolds reinforced with natural silk fibers for bone tissue engineering.

    Science.gov (United States)

    Mobini, Sahba; Hoyer, Birgit; Solati-Hashjin, Mehran; Lode, Anja; Nosoudi, Nasim; Samadikuchaksaraei, Ali; Gelinsky, Michael

    2013-08-01

    We introduce a novel Bombyx mori silk-based composite material developed for bone tissue engineering. Three-dimensional scaffolds were fabricated by embedding of natural degummed silk fibers in a matrix of regenerated fibroin, followed by freeze-drying. Different ratios of fibers to fibroin were investigated with respect to their influence on mechanical and biological properties. For all scaffold types, an interconnected porous structure suitable for cell penetration was proven by scanning electron microscopy. Compressive tests, carried out in static and cyclic mode under dry as well as wet conditions, revealed a strong impact of fiber reinforcement on compressive modulus and compressive stress. Cell culture experiments with human mesenchymal stem cells demonstrated that the fiber/fibroin composite scaffolds support cell attachment, proliferation, as well as differentiation along the osteoblastic lineage. Considering the excellent mechanical and biological properties, novel fiber/fibroin scaffolds appear to be an interesting structure for prospect studies in bone tissue engineering. Copyright © 2013 Wiley Periodicals, Inc.

  15. Biomimetic, Osteoconductive Non-mulberry Silk Fiber Reinforced Tricomposite Scaffolds for Bone Tissue Engineering.

    Science.gov (United States)

    Gupta, Prerak; Adhikary, Mimi; M, Joseph Christakiran; Kumar, Manishekhar; Bhardwaj, Nandana; Mandal, Biman B

    2016-11-16

    Composite biomaterials as artificial bone graft materials are pushing the present frontiers of bioengineering. In this study, a biomimetic, osteoconductive tricomposite scaffold made of hydroxyapatite (HA) embedded in non-mulberry Antheraea assama (A. assama) silk fibroin fibers and its fibroin solution is explored for its osteogenic potential. Scaffolds were physico-chemically characterized for morphology, porosity, secondary structure conformation, water retention ability, biodegradability, and mechanical property. The results revealed a ∼5-fold increase in scaffold compressive modulus on addition of HA and silk fibers to liquid silk as compared to pure silk scaffolds while maintaining high scaffold porosity (∼90%) with slower degradation rates. X-ray diffraction (XRD) results confirmed deposition of HA crystals on composite scaffolds. Furthermore, the crystallite size of HA within scaffolds was strongly regulated by the intrinsic physical cues of silk fibroin. Fourier transform infrared (FTIR) spectroscopy studies indicated strong interactions between HA and silk fibroin. The fabricated tricomposite scaffolds supported enhanced cellular viability and function (ALP activity) for both MG63 osteosarcoma and human bone marrow stem cells (hBMSCs) as compared to pure silk scaffolds without fiber or HA addition. In addition, higher expression of osteogenic gene markers such as collagen I (Col-I), osteocalcin (OCN), osteopontin (OPN), and bone sialoprotein (BSP) further substantiated the applicability of HA composite silk scaffolds for bone related applications. Immunostaining studies confirmed localization of Col-I and BSP and were in agreement with real-time gene expression results. These findings demonstrate the osteogenic potential of developed biodegradable tricomposite scaffolds with the added advantage of the affordability of its components as bone graft substitute materials.

  16. Effect of Pore Size on the Biodegradation Rate of Silk Fibroin Scaffolds

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    Zuwei Luo

    2015-01-01

    Full Text Available Controlling the degradation rate of silk fibroin-based biomaterial is an important capability for the fabrication of silk-based tissue engineering scaffolds. In this study, scaffolds with different pore sizes were prepared by controlling the freezing temperature and the silk fibroin concentration. In vitro degradation results showed that the internal pore walls of the scaffolds with a larger pore size collapsed upon exposure to collagenase IA for times ranging from 6 to 12 days, and the silk scaffolds exhibited a faster rate of weight loss. The morphological and structural features of the silk scaffolds with a smaller pore size maintained structural integrity after incubation in the protease solution for 18 days, and the rate of weight loss was relatively slow. Scaffolds with a smaller pore size or a higher pore density degraded more slowly than scaffolds with a larger pore size or lower pore density. These results demonstrate that the pore size of silk biomaterials is crucial in controlling the degradation rate of tissue engineering scaffolds.

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

    Science.gov (United States)

    Wang, Jianhua; Yang, Qiu; Cheng, Niangmei; Tao, Xiaojun; Zhang, Zhihua; Sun, Xiaomin; Zhang, Qiqing

    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.

  18. 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.

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

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    Ning Cheng

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

  20. 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.

  1. Long-term effects of knitted silk-collagen sponge scaffold on anterior cruciate ligament reconstruction and osteoarthritis prevention.

    Science.gov (United States)

    Shen, Weiliang; Chen, Xiao; Hu, Yejun; Yin, Zi; Zhu, Ting; Hu, Jiajie; Chen, Jialin; Zheng, Zefeng; Zhang, Wei; Ran, Jisheng; Heng, Boon Chin; Ji, Junfeng; Chen, Weishan; Ouyang, Hong-Wei

    2014-09-01

    Anterior cruciate ligament (ACL) is difficult to heal after injury due to the dynamic fluid environment of joint. Previously, we have achieved satisfactory regeneration of subcutaneous tendon/ligament with knitted silk-collagen sponge scaffold due to its specific "internal-space-preservation" property. This study aims to investigate the long-term effects of knitted silk-collagen sponge scaffold on ACL regeneration and osteoarthritis prevention. The knitted silk-collagen sponge scaffold was fabricated and implanted into a rabbit ACL injury model. The knitted silk-collagen sponge scaffold was found to enhance migration and adhesion of spindle-shaped cells into the scaffold at 2 months post-surgery. After 6 months, ACL treated with the knitted silk-collagen sponge scaffold exhibited increased expression of ligament genes and better microstructural morphology. After 18 months, the knitted silk-collagen sponge scaffold-treated group had more mature ligament structure and direct ligament-to-bone healing. Implanted knitted silk-collagen sponge scaffolds degraded much more slowly compared to subcutaneous implantation. Furthermore, the knitted silk-collagen sponge scaffold effectively protected joint surface cartilage and preserved joint space for up to 18 months post-surgery. These findings thus demonstrated that the knitted silk-collagen sponge scaffold can regenerate functional ACL and prevent osteoarthritis in the long-term, suggesting its clinical use as a functional bioscaffold for ACL reconstruction.

  2. Preparation of Porous Scaffolds from Silk Fibroin Extracted from the Silk Gland of Bombyx mori (B. mori

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    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. The Relationship between Secondary Structure and Biodegradation Behavior of Silk Fibroin Scaffolds

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    Yongpei Hu

    2012-01-01

    Full Text Available Silk fibroin has a unique and useful combination of properties, including good biocompatibility and excellent mechanical performance. These features provided early clues to the utility of regenerated silk fibroin as a scaffold/matrix for tissue engineering. The silk fibroin scaffolds used for tissue engineering should degrade at a rate that matches the tissue growth rate. The relationship between secondary structure and biodegradation behavior of silk fibroin scaffolds was investigated in this study. Scaffolds with different secondary structure were prepared by controlling the freezing temperature and by treatment with carbodiimide or ethanol. The quantitative proportions of each secondary structure were obtained by Fourier transform infrared spectroscopy (FTIR, and each sample was then degraded in vitro with collagenase IA for 18 days. The results show that a high content of β-sheet structure leads to a low degradation rate. The random coil region in the silk fibroin material is degraded, whereas the crystal region remains stable and the amount of β-sheet structure increases during incubation. The results demonstrate that it is possible to control the degradation rate of a silk fibroin scaffold by controlling the content of β-sheet structure.

  4. Bilayered silk/silk-nanoCaP scaffolds for osteochondral tissue engineering: In vitro and in vivo assessment of biological performance.

    Science.gov (United States)

    Yan, Le-Ping; Silva-Correia, Joana; Oliveira, Mariana B; Vilela, Carlos; Pereira, Hélder; Sousa, Rui A; Mano, João F; Oliveira, Ana L; Oliveira, Joaquim M; Reis, Rui L

    2015-01-01

    Novel porous bilayered scaffolds, fully integrating a silk fibroin (SF) layer and a silk-nano calcium phosphate (silk-nanoCaP) layer for osteochondral defect (OCD) regeneration, were developed. Homogeneous porosity distribution was achieved in the scaffolds, with calcium phosphate phase only retained in the silk-nanoCaP layer. The scaffold presented compressive moduli of 0.4MPa in the wet state. Rabbit bone marrow mesenchymal stromal cells (RBMSCs) were cultured on the scaffolds, and good adhesion and proliferation were observed. The silk-nanoCaP layer showed a higher alkaline phosphatase level than the silk layer in osteogenic conditions. Subcutaneous implantation in rabbits demonstrated weak inflammation. In a rabbit knee critical size OCD model, the scaffolds firmly integrated into the host tissue. Histological and immunohistochemical analysis showed that collagen II positive cartilage and glycosaminoglycan regeneration presented in the silk layer, and de novo bone ingrowths and vessel formation were observed in the silk-nanoCaP layer. These bilayered scaffolds can therefore be promising candidates for OCD regeneration.

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

    Institute of Scientific and Technical Information of China (English)

    Ting-gang Wang; Jie Xu; Ai-hua Zhu; Hua Lu; Zong-ning Miao; Peng Zhao; Guo-zhen Hui; Wei-jiangWu

    2016-01-01

    Treatment and functional reconstruction atfer 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 artiifcial scaffold materials, such as ifbroin, for nerve repair. However, such approaches are challenged by ethical and practical issues. Amniotic tissue, a clinical waste product, is abundant, and amniotic epithe-lial cells are pluripotent, have low immunogenicity, and are not the subject of ethical debate. We hypothesized that amniotic epithelial cells combined with silk ifbroin 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 ifbroin 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 inlfammatory cell inifltration at the trans-plant site, milder host-versus-gratf reaction, and a marked improvement in motor function. hTese ifndings conifrm that the transplantation of amniotic epithelial cells combined with silk ifbroin scaffold can promote the repair of spinal cord injury. Silk ifbroin scaffold can provide a good nerve regeneration microenvironment for amniotic epithelial cells.

  6. CONFOCAL MICROSCOPY STUDY OF BIOLOGICAL PECULIARITIES OF SCAFFOLD MADE FROM RECOMBINANT SPIDER SILK

    Directory of Open Access Journals (Sweden)

    O. L. Pustovalova

    2009-01-01

    Full Text Available We studied the viability and dynamic of cell distribution during long-term cultivation of broblasts 3T3 in spider silk spidroin 1-based scaffold. Laser scanning confocal microscopy is shown to have advantages for visualization of cells situated on the external and internal surfaces of scaffold. Fibroblasts maintain high proliferative ability and viability during long term cultivation. Spidroin 1-based scaffold are the perspective materials for bioengineering. 

  7. Hybrid scaffolds based on PLGA and silk for bone tissue engineering.

    Science.gov (United States)

    Sheikh, Faheem A; Ju, Hyung Woo; Moon, Bo Mi; Lee, Ok Joo; Kim, Jung-Ho; Park, Hyun Jung; Kim, Dong Wook; Kim, Dong-Kyu; Jang, Ji Eun; Khang, Gilson; Park, Chan Hum

    2016-03-01

    Porous silk scaffolds, which are considered to be natural polymers, cannot be used alone because they have a long degradation rate, which makes it difficult for them to be replaced by the surrounding tissue. Scaffolds composed of synthetic polymers, such as PLGA, have a short degradation rate, lack hydrophilicity and their release of toxic by-products makes them difficult to use. The present investigations aimed to study hybrid scaffolds fabricated from PLGA, silk and hydroxyapatite nanoparticles (Hap NPs) for optimized bone tissue engineering. The results from variable-pressure field emission scanning electron microscopy (VP-FE-SEM), equipped with EDS, confirmed that the fabricated scaffolds had a porous architecture, and the location of each component present in the scaffolds was examined. Contact angle measurements confirmed that the introduction of silk and HAp NPs helped to change the hydrophobic nature of PLGA to hydrophilic, which is the main constraint for PLGA used as a biomaterial. Thermo-gravimetric analysis (TGA) and FT-IR spectroscopy confirmed thermal decomposition and different vibrations caused in functional groups of compounds used to fabricate the scaffolds, which reflected improvement in their mechanical properties. After culturing osteoblasts for 1, 7 and 14 days in the presence of scaffolds, their viability was checked by MTT assay. The fluorescent microscopy results revealed that the introduction of silk and HAp NPs had a favourable impact on the infiltration of osteoblasts. In vivo experiments were conducted by implanting scaffolds in rat calvariae for 4 weeks. Histological examinations and micro-CT scans from these experiments revealed beneficial attributes offered by silk fibroin and HAp NPs to PLGA-based scaffolds for bone induction.

  8. In vitro chondrogenic differentiation of human adipose-derived stem cells with silk scaffolds

    Directory of Open Access Journals (Sweden)

    Hyeon Joo Kim

    2012-12-01

    Full Text Available Human adipose-derived stem cells have shown chondrogenic differentiation potential in cartilage tissue engineering in combination with natural and synthetic biomaterials. In the present study, we hypothesized that porous aqueous-derived silk protein scaffolds would be suitable for chondrogenic differentiation of human adipose-derived stem cells. Human adipose-derived stem cells were cultured up to 6 weeks, and cell proliferation and chondrogenic differentiation were investigated and compared with those in conventional micromass culture. Cell proliferation, glycosaminoglycan, and collagen levels in aqueous-derived silk scaffolds were significantly higher than in micromass culture. Transcript levels of SOX9 and type II collagen were also upregulated in the cell–silk constructs at 6 weeks. Histological examination revealed that the pores of the silk scaffolds were filled with cells uniformly distributed. In addition, chondrocyte-specific lacunae formation was evident and distributed in the both groups. The results suggest the biodegradable and biocompatible three-dimensional aqueous-derived silk scaffolds provided an improved environment for chondrogenic differentiation compared to micromass culture.

  9. 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.

  10. Carboxymethyl cellulose enables silk fibroin nanofibrous scaffold with enhanced biomimetic potential for bone tissue engineering application.

    Science.gov (United States)

    Singh, B N; Panda, N N; Mund, R; Pramanik, K

    2016-10-20

    Novel silk fibroin (SF) and carboxymethyl cellulose (CMC) composite nanofibrous scaffold (SFC) were developed to investigate their ability to nucleate bioactive nanosized calcium phosphate (Ca/P) by biomineralization for bone tissue engineering application. The composite nanofibrous scaffold was prepared by free liquid surface electrospinning method. The developed composite nanofibrous scaffold was observed to control the size of Ca/P particle (≤100nm) as well as uniform nucleation of Ca/P over the surface. The obtained nanofibrous scaffolds were fully characterized for their functional, structural and mechanical property. The XRD and EDX analysis depicted the development of apatite like crystals over SFC scaffolds of nanospherical in morphology and distributed uniformly throughout the surface of scaffold. Additionally, hydrophilicity as a measure of contact angle and water uptake capacity is higher than pure SF scaffold representing the superior cell supporting property of the SF/CMC scaffold. The effect of biomimetic Ca/P on osteogenic differentiation of umbilical cord blood derived human mesenchymal stem cells (hMSCs) studied in early and late stage of differentiation shows the improved osteoblastic differentiation capability as compared to pure silk fibroin. The obtained result confirms the positive correlation of alkaline phosphatase activity, alizarin staining and expression of runt-related transcription factor 2, osteocalcin and type1 collagen representing the biomimetic property of the scaffolds. Thus, the developed composite has been demonstrated to be a potential scaffold for bone tissue engineering application.

  11. A Biomimetic Heparinized Composite Silk-Based Vascular Scaffold with sustained Antithrombogenicity.

    Science.gov (United States)

    Zamani, Masoud; Khafaji, Mona; Naji, Mohammad; Vossoughi, Manouchehr; Alemzadeh, Iran; Haghighipour, Nooshin

    2017-06-30

    Autologous grafts, as the gold standard for vascular bypass procedures, associated with several problems that limit their usability, so tissue engineered vessels have been the subject of an increasing number of works. Nevertheless, gathering all of the desired characteristics of vascular scaffolds in the same construct has been a big challenge for scientists. Herein, a composite silk-based vascular scaffold (CSVS) was proposed to consider all the mechanical, structural and biological requirements of a small-diameter vascular scaffold. The scaffold's lumen composed of braided silk fiber-reinforced silk fibroin (SF) sponge covalently heparinized (H-CSVS) using Hydroxy-Iron Complexes (HICs) as linkers. The highly porous SF external layer with pores above 60 μm was obtained by lyophilization. Silk fibers were fully embedded in scaffold's wall with no delamination. The H-CSVS exhibited much higher burst pressure and suture retention strength than native vessels while comparable elastic modulus and compliance. H-CSVSs presented milder hemolysis in vitro and significant calcification resistance in subcutaneous implantation compared to non-heparinized ones. The in vitro antithrombogenic activity was sustained for over 12 weeks. The cytocompatibility was approved using endothelial cells (ECs) and vascular smooth muscle cells (SMCs) in vitro. Therefore, H-CSVS demonstrates a promising candidate for engineering of small-diameter vessels.

  12. Preparation of uniaxial multichannel silk fibroin scaffolds for guiding primary neurons.

    Science.gov (United States)

    Zhang, Qiang; Zhao, Yahong; Yan, Shuqin; Yang, Yumin; Zhao, Huijing; Li, Mingzhong; Lu, Shenzhou; Kaplan, David L

    2012-07-01

    Physical guidance cues have been exploited to stimulate neuron adhesion and neurite outgrowth. In the present study, three-dimensional (3-D) silk fibroin scaffolds with uniaxial multichannels (42-142 μm in diameter) were prepared by a directional temperature field freezing technique, followed by lyophilization. By varying the initial silk fibroin concentration, the chemical potential and quantity of free water around cylindrical ice crystals could be controlled to control the cross-section morphology of the scaffold channels. Aligned ridges also formed on the inner surface of the multichannels in parallel to the direction of the channels. In vitro, primary hippocampal neurons were seeded in these 3-D silk fibroin scaffolds with uniaxial multichannels of ∼120 μm in diameter. The morphology of the neurons was multipolar and alignment along the scaffold channels was observed. Cell-cell networks and cell-matrix interactions established by newly formed axons were observed after 7 days in culture. These neurons expressed β-III-tubulin, nerve filament and microtubule-associated protein, while glial fibrillary acidic protein immunofluorescence was barely above background. The ridges on the inner surface of the channels played a critical role in the adhesion and extension of neurons by providing continuous contact guidance. These new 3-D silk scaffolds with uniaxial multichannels provided a favorable microenvironment for the development of hippocampal neurons by guiding axonal elongation and cell migration.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Zhengbing; Wen, Jianchuan [State Key Laboratory of Molecular Engineering of Polymers, Advanced Materials Laboratory, Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Yao, Jinrong, E-mail: yaoyaojr@fudan.edu.cn [State Key Laboratory of Molecular Engineering of Polymers, Advanced Materials Laboratory, Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Chen, Xin [State Key Laboratory of Molecular Engineering of Polymers, Advanced Materials Laboratory, Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Ni, Yusu [Otology and Skull Base Surgery Department, Eye and ENT Hospital of Fudan University, Shanghai 200031 (China); Shao, Zhengzhong [State Key Laboratory of Molecular Engineering of Polymers, Advanced Materials Laboratory, Department of Macromolecular Science, Fudan University, Shanghai 200433 (China)

    2013-08-01

    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, {sup 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sangkert, Supaporn [Biological Materials for Medicine Research Unit, Faculty of Medicine, Institute of Biomedical Engineering, Prince of Songkla University, Hat Yai, Songkhla90110 (Thailand); Meesane, Jirut, E-mail: jirutmeesane999@yahoo.co.uk [Biological Materials for Medicine Research Unit, Faculty of Medicine, Institute of Biomedical Engineering, Prince of Songkla University, Hat Yai, Songkhla90110 (Thailand); Kamonmattayakul, Suttatip [Faculty of Dentistry, Department of Preventive Dentistry, Prince of Songkla University, Hat Yai, Songkhla90110 (Thailand); Chai, Wen Lin [Faculty of Dentistry, Department of General Dental Practice and Oral and Maxillofacial Imaging, University of Malaya, Kuala Lumpur (Malaysia)

    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

  15. Enhanced redifferentiation of chondrocytes on microperiodic silk/gelatin scaffolds: toward tailor-made tissue engineering.

    Science.gov (United States)

    Das, Sanskrita; Pati, Falguni; Chameettachal, Shibu; Pahwa, Shikha; Ray, Alok R; Dhara, Santanu; Ghosh, Sourabh

    2013-02-11

    Direct-write assembly allows rapid fabrication of complex three-dimensional (3D) architectures, such as scaffolds simulating anatomical shapes, avoiding the need for expensive lithographic masks. However, proper selection of polymeric ink composition and tailor-made viscoelastic properties are critically important for smooth deposition of ink and shape retention. Deposition of only silk solution leads to frequent clogging due to shear-induced β-sheet crystallization, whereas optimized viscoelastic property of silk-gelatin blends facilitate the flow of these blends through microcapillary nozzles of varying diameter. This study demonstrates that induction of controlled changes in scaffold surface chemistry, by optimizing silk-gelatin ratio, can govern cell proliferation and maintenance of chondrocyte morphology. Microperiodic silk-gelatin scaffolds can influence postexpansion redifferentiation of goat chondrocytes by enhancing Sox-9 gene expression, aggregation, and driving cartilage matrix production, as evidenced by upregulation of collagen type II and aggrecan expression. The strategy for optimizing redifferentiation of chondrocytes can offer valuable consideration in scaffold-based cartilage repair strategies.

  16. Bioengineered silk scaffolds in 3D tissue modeling with focus on mammary tissues.

    Science.gov (United States)

    Maghdouri-White, Yas; Bowlin, Gary L; Lemmon, Christopher A; Dréau, Didier

    2016-02-01

    In vitro generation of three-dimensional (3D) biological tissues and organ-like structures is a promising strategy to study and closely model complex aspects of the molecular, cellular, and physiological interactions of tissue. In particular, in vitro 3D tissue modeling holds promises to further our understanding of breast development. Indeed, biologically relevant 3D structures that combine mammary cells and engineered matrices have improved our knowledge of mammary tissue growth, organization, and differentiation. Several polymeric biomaterials have been used as scaffolds to engineer 3D mammary tissues. Among those, silk fibroin-based biomaterials have many biologically relevant properties and have been successfully used in multiple medical applications. Here, we review the recent advances in engineered scaffolds with an emphasis on breast-like tissue generation and the benefits of modified silk-based scaffolds.

  17. Evaluation of menstrual blood stem cells seeded in biocompatible Bombyx mori silk fibroin scaffold for cardiac tissue engineering.

    Science.gov (United States)

    Rahimi, Maryam; Mohseni-Kouchesfehani, Homa; Zarnani, Amir-Hassan; Mobini, Sahba; Nikoo, Shohreh; Kazemnejad, Somaieh

    2014-08-01

    Recently, silk fibroin scaffolds have been introduced as novel and promising biomaterials in the field of cardiac tissue engineering. This study was designed to compare infiltration, proliferation, and cardiac differentiation potential of menstrual blood-derived stem cells (MenSCs) versus bone marrow-derived mesenchymal stem cells (BMSCs) in Bombyx mori-derived silk scaffold. Our primary data revealed that the fabricated scaffold has mechanical and physical qualities suitable for cardiac tissue engineering. The MenSCs tracking in scaffolds using immunofluorescent staining and scanning electron microscopy confirmed MenSCs attachment, penetration, and distribution within the porous scaffold matrix. Based on proliferation assay using propidium iodide DNA quantification, the significantly higher level of growth rates of both MenSCs and BMSCs was documented in scaffolds than that in two-dimensional culture (p < 0.01). The expression level of TNNT2, a bona fide cardiac differentiation marker, in BMSCs differentiated on silk scaffolds was markedly higher than those cultured in two-dimensional culture indicating the improvement of cardiac differentiation in the silk scaffolds. Furthermore, differentiated MenSCs exhibited higher expression of TNNT2 compared with induced BMSCs. It seems that silk scaffold-seeded MenSCs could be viewed as a novel, safe, natural, and accessible construct for cardiac tissue engineering. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  18. Accelerated healing of full-thickness wounds by genipin-crosslinked silk sericin/PVA scaffolds.

    Science.gov (United States)

    Aramwit, Pornanong; Siritienthong, Tippawan; Srichana, Teerapol; Ratanavaraporn, Juthamas

    2013-01-01

    Silk sericin has recently been studied for its advantageous biological properties, including its ability to promote wound healing. This study developed a delivery system to accelerate the healing of full-thickness wounds. Three-dimensional scaffolds were fabricated from poly(vinyl alcohol) (PVA), glycerin (as a plasticizer) and genipin (as a crosslinking agent), with or without sericin. The physical and biological properties of the genipin-crosslinked sericin/PVA scaffolds were investigated and compared with those of scaffolds without sericin. The genipin-crosslinked sericin/PVA scaffolds exhibited a higher compressive modulus and greater swelling in water than the scaffolds without sericin. Sericin also exhibited controlled release from the scaffolds. The genipin-crosslinked sericin/PVA scaffolds promoted the attachment and proliferation of L929 mouse fibroblasts. After application to full-thickness rat wounds, the wounds treated with genipin-crosslinked sericin/PVA scaffolds showed a significantly greater reduction in wound size, collagen formation and epithelialization compared with the control scaffolds without sericin but lower numbers of macrophages and multinucleated giant cells. These results indicate that the delivery of sericin from the novel genipin-crosslinked scaffolds efficiently healed the wound. Therefore, these genipin-crosslinked sericin/PVA scaffolds represent a promising candidate for the accelerated healing of full-thickness wounds.

  19. A Biomimetic Silk Fibroin/Sodium Alginate Composite Scaffold for Soft Tissue Engineering

    Science.gov (United States)

    Wang, Yiyu; Wang, Xinyu; Shi, Jian; Zhu, Rong; Zhang, Junhua; Zhang, Zongrui; Ma, Daiwei; Hou, Yuanjing; Lin, Fei; Yang, Jing; Mizuno, Mamoru

    2016-01-01

    A cytocompatible porous scaffold mimicking the properties of extracellular matrices (ECMs) has great potential in promoting cellular attachment and proliferation for tissue regeneration. A biomimetic scaffold was prepared using silk fibroin (SF)/sodium alginate (SA) in which regular and uniform pore morphology can be formed through a facile freeze-dried method. The scanning electron microscopy (SEM) studies showed the presence of interconnected pores, mostly spread over the entire scaffold with pore diameter around 54~532 μm and porosity 66~94%. With significantly better water stability and high swelling ratios, the blend scaffolds crosslinked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) provided sufficient time for the formation of neo-tissue and ECMs during tissue regeneration. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) results confirmed random coil structure and silk I conformation were maintained in the blend scaffolds. What’s more, FI-TR spectra demonstrated crosslinking reactions occurred actually among EDC, SF and SA macromolecules, which kept integrity of the scaffolds under physiological environment. The suitable pore structure and improved equilibrium swelling capacity of this scaffold could imitate biochemical cues of natural skin ECMs for guiding spatial organization and proliferation of cells in vitro, indicating its potential candidate material for soft tissue engineering. PMID:27996001

  20. In vitro evaluation of the biological performance of macro/micro-porous silk fibroin and silk-nano calcium phosphate scaffolds.

    Science.gov (United States)

    Yan, L-P; Oliveira, J M; Oliveira, A L; Reis, R L

    2015-05-01

    This study evaluates the biological performance of salt-leached macro/microporous silk scaffolds (S16) and silk-nano calcium phosphate scaffolds (SC16), both deriving from a 16 wt % aqueous SF solution. Enzymatic degradation results showed that the silk-based scaffolds presented desirable biostability, and the incorporation of calcium phosphate further improved the scaffolds' biostability. Human adipose tissue derived stromal cells (hASCs) were cultured onto the scaffolds in vitro. The Alamar blue assay and DNA content revealed that both scaffolds were non-cytotoxic and can support the viability and proliferation of the hASCs. Scanning electron microscopy observation demonstrated that the microporous structure was beneficial for the cell adhesion while the macroporous structure favored the cell migration and proliferation. The histological analysis displayed abundant extracellular matrix formed inside the scaffolds, leading to the significant increase of scaffolds' modulus. These results revealed that S16 and SC16 could be promising alternatives for cartilage and bone tissue engineering scaffolding applications, respectively.

  1. Comparative evaluation of in vivo biocompatibility and biodegradability of regenerated silk scaffolds reinforced with/without natural silk fibers.

    Science.gov (United States)

    Mobini, Sahba; Taghizadeh-Jahed, Masoud; Khanmohammadi, Manijeh; Moshiri, Ali; Naderi, Mohammad-Mehdi; Heidari-Vala, Hamed; Ashrafi Helan, Javad; Khanjani, Sayeh; Springer, Armin; Akhondi, Mohammad-Mehdi; Kazemnejad, Somaieh

    2016-01-01

    Nowadays, exceptional advantages of silk fibroin over synthetic and natural polymers have impelled the scientists to application of this biomaterial for tissue engineering purposes. Recently, we showed that embedding natural degummed silk fibers in regenerated Bombyx mori silk-based scaffold significantly increases the mechanical stiffness, while the porosity of the scaffolds remains the same. In the present study, we evaluated degradation rate, biocompatibility and regenerative properties of the regenerated 2% and 4% wt silk-based composite scaffolds with or without embedded natural degummed silk fibers within 90 days in both athymic nude and wild-type C57BL/6 mice through subcutaneous implantation. In all scaffolds, a suitable interconnected porous structure for cell penetration was seen under scanning electron microscopy. Compressive tests revealed a functional relationship between fiber reinforcement and compressive modulus. In addition, the fiber/fibroin composite scaffolds support cell attachment and proliferation. On days 30 to 90 after subcutaneous implantation, the retrieved tissues were examined via gross morphology, histopathology, immunofluorescence staining and reverse transcription-polymerase chain reaction as shown in Figure 1. Results showed that embedding the silk fibers within the matrix enhances the biodegradability of the matrix resulting in replacement of the composite scaffolds with the fresh connective tissue. Fortification of the composites with degummed fibers not only regulates the degradation profile but also increases the mechanical performance of the scaffolds. This report also confirmed that pore size and structure play an important role in the degradation rate. In conclusion, the findings of the present study narrate key role of additional surface area in improving in vitro and in vivo biological properties of the scaffolds and suggest the potential ability of these fabricated composite scaffolds for connective tissue regeneration

  2. Anterior cruciate ligament reconstruction in a rabbit model using silk-collagen scaffold and comparison with autograft.

    Directory of Open Access Journals (Sweden)

    Fanggang Bi

    Full Text Available The objective of the present study was to perform an in vivo assessment of a novel silk-collagen scaffold for anterior cruciate ligament (ACL reconstruction. First, a silk-collagen scaffold was fabricated by combining sericin-extracted knitted silk fibroin mesh and type I collagen to mimic the components of the ligament. Scaffolds were electron-beam sterilized and rolled up to replace the ACL in 20 rabbits in the scaffold group, and autologous semitendinosus tendons were used to reconstruct the ACL in the autograft control group. At 4 and 16 weeks after surgery, grafts were retrieved and analyzed for neoligament regeneration and tendon-bone healing. To evaluate neoligament regeneration, H&E and immunohistochemical staining was performed, and to assess tendon-bone healing, micro-CT, biomechanical test, H&E and Russell-Movat pentachrome staining were performed. Cell infiltration increased over time in the scaffold group, and abundant fibroblast-like cells were found in the core of the scaffold graft at 16 weeks postoperatively. Tenascin-C was strongly positive in newly regenerated tissue at 4 and 16 weeks postoperatively in the scaffold group, similar to observations in the autograft group. Compared with the autograft group, tendon-bone healing was better in the scaffold group with trabecular bone growth into the scaffold. The results indicate that the silk-collagen scaffold has considerable potential for clinical application.

  3. Structure-property relationship of regenerated spider silk protein nano/microfibrous scaffold fabricated by electrospinning.

    Science.gov (United States)

    Yu, Qiaozhen; Xu, Shuiling; Zhang, Hong; Gu, Li; Xu, Yepei; Ko, Frank

    2014-11-01

    The regenerated Araneus ventricosus spider dragline silk protein fibrous scaffold with moderate strength and flexibility was fabricated by electrospinning and post treatment with 90 vol % acetone. The effect of collection method on the morphology of regenerated spider silk protein (RSSP) fibrous scaffold, the effects of the post treatment solvents and their concentrations on the molecular conformation, crystallinity and mechanical properties were studied. The results show that the morphology was affected by the solvent used in the coagulation bath. The molecular conformation, crystallinity and mechanical property of this scaffold were strongly affected by the kind of post treatment solvent and slightly influenced by its concentration when it was higher than 50 vol %. The degradation rate of this scaffold was very slow and resulting in little pH change of the degradation medium within 5 months. PC 12 cells were cultured on the electrospun RSSP fibrous scaffold and in its extraction fluid to examine the changes of PC 12 cells after different times of culture. The results show that the electrospun RSSP fibrous scaffold had good biocompatibility with PC 12 cells. © 2013 Wiley Periodicals, Inc.

  4. Relationship between gelatin concentrations in silk fibroin-based composite scaffolds and adhesion and proliferation of mouse embryo fibroblasts.

    Science.gov (United States)

    Orlova, A A; Kotlyarova, M S; Lavrenov, V S; Volkova, S V; Arkhipova, A Yu

    2014-11-01

    Porous scaffolds of silk fibroin and composite porous scaffolds with 10, 20, 30, 40, and 50% gelatin were made by the freezing-thawing method. The relationship between adhesion and proliferation rate mouse embryo fibroblast and the scaffold composition was studied by laser confocal scanning microscopy. Addition of gelatin to the scaffold structure stimulated adhesion and proliferation of mouse embryo fibroblasts; the optimal content of gelatin was 30%.

  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.

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

    Science.gov (United States)

    Shao, Weili; He, Jianxin; Sang, Feng; Ding, Bin; Chen, Li; Cui, Shizhong; Li, Kejing; Han, Qiming; Tan, Weilin

    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.

  7. [Application of silk-based tissue engineering scaffold for tendon / ligament regeneration].

    Science.gov (United States)

    Hu, Yejun; Le, Huihui; Jin, Zhangchu; Chen, Xiao; Yin, Zi; Shen, Weiliang; Ouyang, Hongwei

    2016-03-01

    Tendon/ligament injury is one of the most common impairments in sports medicine. The traditional treatments of damaged tissue repair are unsatisfactory, especially for athletes, due to lack of donor and immune rejection. The strategy of tissue engineering may break through these limitations, and bring new hopes to tendon/ligament repair, even regeneration. Silk is a kind of natural biomaterials, which has good biocompatibility, wide range of mechanical properties and tunable physical structures; so it could be applied as tendon/ligament tissue engineering scaffolds. The silk-based scaffold has robust mechanical properties; combined with other biological ingredients, it could increase the surface area, promote more cell adhesion and improve the biocompatibility. The potential clinical application of silk-based scaffold has been confirmed by in vivo studies on tendon/ligament repairing, such as anterior cruciate ligament, medial collateral ligament, achilles tendon and rotator cuff. To develop novel biomechanically stable and host integrated tissue engineered tendon/ligament needs more further micro and macro studies, combined with product development and clinical application, which will give new hope to patients with tendon/ligament injury.

  8. Silk-Hydroxyapatite Nanoscale Scaffolds with Programmable Growth Factor Delivery for Bone Repair.

    Science.gov (United States)

    Ding, Zhaozhao; Fan, Zhihai; Huang, Xiaowei; Lu, Qiang; Xu, Weian; Kaplan, David L

    2016-09-21

    Osteoinductive biomaterials are attractive for repairing a variety of bone defects, and biomimetic strategies are useful toward developing bone scaffolds with such capacity. Here, a multiple biomimetic design was developed to improve the osteogenesis capacity of composite scaffolds consisting of hydroxyapatite nanoparticles (HA) and silk fibroin (SF). SF nanofibers and water-dispersible HA nanoparticles were blended to prepare the nanoscaled composite scaffolds with a uniform distribution of HA with a high HA content (40%), imitating the extracellular matrix (ECM) of bone. Bone morphogenetic protein-2 (BMP-2) was loaded in the SF scaffolds and HA to tune BMP-2 release. In vitro studies showed the preservation of BMP-2 bioactivity in the composite scaffolds, and programmable sustained release was achieved through adjusting the ratio of BMP-2 loaded on SF and HA. In vitro and in vivo osteogenesis studies demonstrated that the composite scaffolds showed improved osteogenesis capacity under suitable BMP-2 release conditions, significantly better than that of BMP-2 loaded SF-HA composite scaffolds reported previously. Therefore, these biomimetic SF-HA nanoscaled scaffolds with tunable BMP-2 delivery provide preferable microenvironments for bone regeneration.

  9. Electrospun silk fibroin/poly(lactide-co-ε-caprolactone nanofibrous scaffolds for bone regeneration

    Directory of Open Access Journals (Sweden)

    Wang Z

    2016-04-01

    Full Text Available Zi Wang,1,* Ming Lin,1,* Qing Xie,1 Hao Sun,1 Yazhuo Huang,1 DanDan Zhang,1 Zhang Yu,1 Xiaoping Bi,1 Junzhao Chen,1 Jing Wang,2 Wodong Shi,1 Ping Gu,1 Xianqun Fan1 1Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 2Biomaterials and Tissue Engineering Laboratory, College of Chemistry & Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Tissue engineering has become a promising therapeutic approach for bone regeneration. Nanofibrous scaffolds have attracted great interest mainly due to their structural similarity to natural extracellular matrix (ECM. Poly(lactide-co-ε-caprolactone (PLCL has been successfully used in bone regeneration, but PLCL polymers are inert and lack natural cell recognition sites, and the surface of PLCL scaffold is hydrophobic. Silk fibroin (SF is a kind of natural polymer with inherent bioactivity, and supports mesenchymal stem cell attachment, osteogenesis, and ECM deposition. Therefore, we fabricated hybrid nanofibrous scaffolds by adding different weight ratios of SF to PLCL in order to find a scaffold with improved properties for bone regeneration.Methods: Hybrid nanofibrous scaffolds were fabricated by blending different weight ratios of SF with PLCL. Human adipose-derived stem cells (hADSCs were seeded on SF/PLCL nanofibrous scaffolds of various ratios for a systematic evaluation of cell adhesion, proliferation, cytotoxicity, and osteogenic differentiation; the efficacy of the composite of hADSCs and scaffolds in repairing critical-sized calvarial defects in rats was investigated.Results: The SF/PLCL (50/50 scaffold exhibited favorable tensile strength, surface roughness, and hydrophilicity, which facilitated cell adhesion and proliferation. Moreover, the SF/PLCL (50/50 scaffold promoted the osteogenic differentiation of hADSCs by elevating the

  10. 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

  11. Fabrication and evaluation of poly(epsilon-caprolactone)/silk fibroin blend nanofibrous scaffold.

    Science.gov (United States)

    Lim, Jun Sik; Ki, Chang Seok; Kim, Jong Wook; Lee, Kwang Gil; Kang, Seok Woo; Kweon, Hae Yong; Park, Young Hwan

    2012-05-01

    In this study we investigated the blend electrospinning of poly(ϵ-caprolactone) (PCL) and silk fibroin (SF) to improve the biodegradability and biocompatibility of PCL-based nanofibrous scaffolds. Optimal conditions to fabricate PCL/SF (50/50) blend nanofiber were established for electrospinning using formic acid as a cosolvent and three-dimensional (3D) PCL/SF blend nanofibrous scaffolds were prepared by a modified electrospinning process using methanol coagulation bath. The physical properties of 2D PCL/SF blend nanofiber mats and 3D highly porous blend nanofibrous scaffolds were measured and compared. To evaluate cytocompatibility of the 3D blend scaffolds as compared to 3D PCL nanofibrous scaffold, normal human dermal fibroblasts were cultured. It is concluded that biodegradability and cytocompatibility could be improved for the 3D highly porous PCL/SF (50/50) blend nanofibrous scaffold prepared by blending PCL with SF in electrospinning. In addition to the blending of PCL and SF, the 3D structure and high porosity of electrospun nanofiber assemblies may also be important factors for enhancing the performance of scaffolds.

  12. A biphasic scaffold based on silk and bioactive ceramic with stratified properties for osteochondral tissue regeneration.

    Science.gov (United States)

    Li, Jiao Jiao; Kim, Kyungsook; Roohani-Esfahani, Seyed-Iman; Guo, Jin; Kaplan, David L; Zreiqat, Hala

    2015-07-14

    Significant clinical challenges encountered in the effective long-term treatment of osteochondral defects have inspired advancements in scaffold-based tissue engineering techniques to aid repair and regeneration. This study reports the development of a biphasic scaffold produced via a rational combination of silk fibroin and bioactive ceramic with stratified properties to satisfy the complex and diverse regenerative requirements of osteochondral tissue. Structural examination showed that the biphasic scaffold contained two phases with different pore morphologies to match the cartilage and bone segments of osteochondral tissue, which were joined at a continuous interface. Mechanical assessment showed that the two phases of the biphasic scaffold imitated the load-bearing behaviour of native osteochondral tissue and matched its compressive properties. In vitro testing showed that different compositions in the two phases of the biphasic scaffold could direct the preferential differentiation of human mesenchymal stem cells towards the chondrogenic or osteogenic lineage. By featuring simple and reproducible fabrication and a well-integrated interface, the biphasic scaffold strategy established in this study circumvented the common problems experienced with integrated scaffold designs and could provide an effective approach for the regeneration of osteochondral tissue.

  13. 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.

  14. 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

    2014-01-01

    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. PMID:28788558

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-01

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

  16. A mild process to design silk scaffolds with reduced β-sheet structure and various topographies at the nanometer scale.

    Science.gov (United States)

    Pei, Yazhen; Liu, Xi; Liu, Shanshan; Lu, Qiang; Liu, Jing; Kaplan, David L; Zhu, Hesun

    2015-02-01

    Three-dimensional (3-D) porous silk scaffolds with good biocompatibility and minimal immunogenicity show promise in a range of tissue regeneration applications. However, the challenge remains to effectively fabricate their microstructures and mechanical properties to satisfy the specific requirements of different tissues. In this study, silk scaffolds were fabricated to form an extracellular matrix (ECM) mimetic nanofibrous architecture using a mild process. A slowly increasing concentration process was applied to regulate silk self-assembly into nanofibers in aqueous solution. Then glycerol was blended with the nanofiber solution and induced silk crystallization in the lyophilization process, endowing freeze-dried scaffolds with water stability. The glycerol was leached from the scaffolds, leaving a similar porous structure at the micrometer scale but different topographies at the nanoscale. Compared to previous salt-leached and methanol-annealed scaffolds, the present scaffolds showed lower β-sheet content, softer mechanical property and improved cell growth and differentiation behaviors, suggesting their promising future as platforms for controlling stem cell fate and soft tissue regeneration.

  17. 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.

  18. Self-assembly of silk-elastinlike protein polymers into three-dimensional scaffolds for biomedical applications

    Science.gov (United States)

    Zeng, Like

    Production of brand new protein-based materials with precise control over the amino acid sequences at single residue level has been made possible by genetic engineering, through which artificial genes can be developed that encode protein-based materials with desired features. As an example, silk-elastinlike protein polymers (SELPs), composed of tandem repeats of amino acid sequence motifs from Bombyx mori (silkworm) silk and mammalian elastin, have been produced in this approach. SELPs have been studied extensively in the past two decades, however, the fundamental mechanism governing the self-assembly process to date still remains largely unresolved. Further, regardless of the unprecedented success when exploited in areas including drug delivery, gene therapy, and tissue augmentation, SELPs scaffolds as a three-dimensional cell culture model system are complicated by the inability of SELPs to provide the embedded tissue cells with appropriate biochemical stimuli essential for cell survival and function. In this dissertation, it is reported that the self-assembly of silk-elastinlike protein polymers (SELPs) into nanofibers in aqueous solutions can be modulated by tuning the curing temperature, the size of the silk blocks, and the charge of the elastin blocks. A core-sheath model was proposed for nanofiber formation, with the silk blocks in the cores and the hydrated elastin blocks in the sheaths. The folding of the silk blocks into stable cores -- affected by the size of the silk blocks and the charge of the elastin blocks -- plays a critical role in the assembly of silk-elastin nanofibers. The assembled nanofibers further form nanofiber clusters on the microscale, and the nanofiber clusters then coalesce into nanofiber micro-assemblies, interconnection of which eventually leads to the formation of three-dimensional scaffolds with distinct nanoscale and microscale features. SELP-Collagen hybrid scaffolds were also fabricated to enable independent control over the

  19. Effect of fetal bovine serum on mineralization in silk fibroin scaffolds.

    Science.gov (United States)

    Vetsch, Jolanda R; Paulsen, Samantha J; Müller, Ralph; Hofmann, Sandra

    2015-02-01

    Fetal bovine serum (FBS) is a common media supplement used in tissue engineering (TE) cultures. The chemical composition of FBS is known to be highly variable between different brands, types or batches and can have a significant impact on cell function. This study investigated the influence of four different FBS types in osteogenic or control medium on mineralization of acellular and cell-seeded silk fibroin (SF) scaffolds. In bone TE, mineralized tissue is considered as the final product of a successful cell culture. Calcium assays and micro-computed tomography scans revealed spontaneous mineralization on SF scaffolds with certain FBS types, even without cells present. In contrast, cell-mediated mineralization was found under osteogenic conditions only. Fourier transform infrared spectroscopy analysis demonstrated a similar ion composition of the mineralization present in scaffolds, whether cell-mediated or spontaneous. These results were confirmed by scanning electron microscopy. This study shows clear evidence for the influence of FBS type on mineralization on SF scaffolds. The suitability of FBS medium supplementation in TE studies is highly questionable with regard to reproducibility of studies and comparability of obtained results. For future TE studies, alternatives to conventional FBS such as defined FBS or serum-free media should be considered, as suggested decades ago.

  20. 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.

  1. Alignment of collagen fiber in knitted silk scaffold for functional massive rotator cuff repair.

    Science.gov (United States)

    Zheng, Zefeng; Ran, Jisheng; Chen, Weishan; Hu, Yejun; Zhu, Ting; Chen, Xiao; Yin, Zi; Heng, Boon Chin; Feng, Gang; Le, Huihui; Tang, Chenqi; Huang, Jiayun; Chen, Yangwu; Zhou, Yiting; Dominique, Pioletti; Shen, Weiliang; Ouyang, Hong-Wei

    2017-03-15

    Rotator cuff tear is one of the most common types of shoulder injuries, often resulting in pain and physical debilitation. Allogeneic tendon-derived decellularized matrices do not have appropriate pore size and porosity to facilitate cell infiltration, while commercially-available synthetic scaffolds are often inadequate at inducing tenogenic differentiation. The aim of this study is to develop an advanced 3D aligned collagen/silk scaffold (ACS) and investigate its efficacy in a rabbit massive rotator cuff tear model. ACS has similar 3D alignment of collagen fibers as natural tendon with superior mechanical characteristics. Based on ectopic transplantation studies, the optimal collagen concentration (10mg/ml), pore diameter (108.43±7.25μm) and porosity (97.94±0.08%) required for sustaining a stable macro-structure conducive for cellular infiltration was determined. Within in vitro culture, tendon stem/progenitor cells (TSPCs) displayed spindle-shaped morphology, and were well-aligned on ACS as early as 24h. TSPCs formed intercellular contacts and deposited extracellular matrix after 7days. With the in vivo rotator cuff repair model, the regenerative tendon of the ACS group displayed more conspicuous native microstructures with larger diameter collagen fibrils (48.72±3.75 vs. 44.26±5.03nm) that had better alignment and mechanical properties (139.85±49.36vs. 99.09±33.98N) at 12weeks post-implantation. In conclusion, these findings demonstrate the positive efficacy of the macroporous 3D aligned scaffold in facilitating rotator cuff tendon regeneration, and its practical applications for rotator cuff tendon tissue engineering. Massive rotator cuff tear is one of the most common shoulder injuries, and poses a formidable clinical challenge to the orthopedic surgeon. Tissue engineering of tendon can potentially overcome the problem. However, more efficacious scaffolds with good biocompatibility, appropriate pore size, favorable inductivity and sufficient mechanical

  2. Comparative repair capacity of knee osteochondral defects using regenerated silk fiber scaffolds and fibrin glue with/without autologous chondrocytes during 36 weeks in rabbit model.

    Science.gov (United States)

    Kazemnejad, Somaieh; Khanmohammadi, Manijeh; Mobini, Sahba; Taghizadeh-Jahed, Masoud; Khanjani, Sayeh; Arasteh, Shaghayegh; Golshahi, Hannaneh; Torkaman, Giti; Ravanbod, Roya; Heidari-Vala, Hamed; Moshiri, Ali; Tahmasebi, Mohammad-Naghi; Akhondi, Mohammad-Mehdi

    2016-06-01

    The reconstruction capability of osteochondral (OCD) defects using silk-based scaffolds has been demonstrated in a few studies. However, improvement in the mechanical properties of natural scaffolds is still challengeable. Here, we investigate the in vivo repair capacity of OCD defects using a novel Bombyx mori silk-based composite scaffold with great mechanical properties and porosity during 36 weeks. After evaluation of the in vivo biocompatibility and degradation rate of these scaffolds, we examined the effectiveness of these fabricated scaffolds accompanied with/without autologous chondrocytes in the repair of OCD lesions of rabbit knees after 12 and 36 weeks. Moreover, the efficiency of these scaffolds was compared with fibrin glue (FG) as a natural carrier of chondrocytes using parallel clinical, histopathological and mechanical examinations. The data on subcutaneous implantation in mice showed that the designed scaffolds have a suitable in vivo degradation rate and regenerative capacity. The repair ability of chondrocyte-seeded scaffolds was typically higher than the scaffolds alone. After 36 weeks of implantation, most parts of the defects reconstructed by chondrocytes-seeded silk scaffolds (SFC) were hyaline-like cartilage. However, spontaneous healing and filling with a scaffold alone did not eventuate in typical repair. We could not find significant differences between quantitative histopathological and mechanical data of SFC and FGC. The fabricated constructs consisting of regenerated silk fiber scaffolds and chondrocytes are safe and suitable for in vivo repair of OCD defects and promising for future clinical trial studies.

  3. Composite poly(l-lactic-acid)/silk fibroin scaffold prepared by electrospinning promotes chondrogenesis for cartilage tissue engineering.

    Science.gov (United States)

    Li, Zhengqiang; Liu, Peng; Yang, Ting; Sun, Ying; You, Qi; Li, Jiale; Wang, Zilin; Han, Bing

    2016-05-01

    Nanofibrous materials produced by electrospinning have attracted considerable attention from researchers in regenerative medicine. A combination of nanofibrous scaffold and chondrocytes is considered promising for repair of cartilage defect or damage. In the present study, we fabricated a poly(l-lactic-acid) (PLLA)/silk fibroin (SF) nanofibrous scaffold by electrospinning and evaluated its chondrogenic potential. The PLLA/SF nanofibers were characterized for diameter, surface wettability, swelling ratio, and tensile strength. Throughin vitroexperiments, PLLA/SF scaffold-chondrocyte interactions were investigated relative to the unmodified PLLA scaffold with regard to cellular adhesion, spreading, and proliferation by scanning electron microscopy and confocal laser scanning microscopy, and through analyses of DNA, sulfated glycosaminoglycan, and collagen. In addition, hematoxylin-eosin and Alcian blue-nuclear fast red staining were used to observe growth of chondrocytes, and secretion and distribution of cartilage-specific extracellular matrices in the scaffolds. Expressions of cartilage-related genes (collagen II, aggrecan, sox9, collagen I, and collagen X) were detected by real-time quantitative PCR. The PLLA/SF scaffold had better hydrophilicity, and could support chondrocytes adhesion and spreading more effectively than the unmodified PLLA scaffold. Chondrocytes secreted more cartilage-specific extracellular matrices and maintained their phenotype on the PLLA/SF scaffold. So it is concluded that the PLLA/SF scaffold is more conducive toin vitroformation of cartilage-like new tissues than the unmodified PLLA scaffold, and may be a promising material in cartilage tissue engineering.

  4. 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.

  5. Preparation and characterization of a bacterial cellulose/silk fibroin sponge scaffold for tissue regeneration.

    Science.gov (United States)

    Oliveira Barud, H G; Barud, Hernane da S; Cavicchioli, Maurício; do Amaral, Thais Silva; de Oliveira Junior, Osmir Batista; Santos, Diego M; Petersen, Antonio Luis de Oliveira Almeida; Celes, Fabiana; Borges, Valéria Matos; de Oliveira, Camila I; de Oliveira, Pollyanna Francielli; Furtado, Ricardo Andrade; Tavares, Denise Crispim; Ribeiro, Sidney J L

    2015-09-05

    Bacterial cellulose (BC) and silk fibroin (SF) are natural biopolymers successfully applied in tissue engineering and biomedical fields. In this work nanocomposites based on BC and SF were prepared and characterized by scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). In addition, the investigation of cytocompatibility was done by MTT, XTT and Trypan Blue dye technique. Cellular adhesion and proliferation were detected additionally. The evaluation of genotoxicity was realized by micronucleus assay. In vitro tests showed that the material is non-cytotoxic or genotoxic. SEM images revealed a greater number of cells attached at the BC/SF:50% scaffold surface than the pure BC one, suggesting that the presence of fibroin improved cell attachment. This could be related to the SF amino acid sequence that acts as cell receptors facilitating cell adhesion and growth. Consequently, BC/SF:50% scaffolds configured an excellent option in bioengineering depicting its potential for tissue regeneration and cultivation of cells on nanocomposites.

  6. Optimized composition of nanocomposite scaffolds formed from silk fibroin and nano-TiO2 for bone tissue engineering.

    Science.gov (United States)

    Johari, N; Madaah Hosseini, H R; Samadikuchaksaraei, A

    2017-10-01

    Natural silk fibroin (SF) polymer has biomedical and mechanical properties as a biomaterial for bone tissue engineering scaffolds. Freeze-dried porous nanocomposite scaffolds were prepared from silk fibroin and titanium dioxide (TiO2) nanoparticles as a bioactive reinforcing agent by a phase separation method. In order to fabricate SF/TiO2 scaffolds, 5, 10, 15 and 20wt% of the TiO2 were added to the SF. The phase structure, functional groups and morphology of the scaffolds were evaluated using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques, respectively. Porosity of the scaffolds was measured by Archimedes' Principle. In addition, mechanical properties of prepared scaffolds were evaluated by measuring the compressive strength and compressive modulus. The bioactivity property of these scaffolds was examined for 7, 14, 21 and 28days immersion in simulated body fluid (SBF) at 37°C and the in vitro degradation was studied by incubation in phosphate buffered saline (PBS) at 37°C and pH7.4 for up to 30days. Moreover, the scaffolds' biocompatibility was evaluated by seeding and culture of SaOS-2 osteoblast-like cells and assessment of their proliferation with MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Results showed that the prepared scaffolds had directional porosity and the reduction of porosity in composite scaffolds with higher contents of TiO2 nanoparticles resulted to an improvement of the mechanical strength. The macroporous structures with open interconnected and directional pores were successfully obtained without applying any porogen or inorganic solvent. The bioactivity of these scaffolds was confirmed by scanning electron microscopy (SEM) showing surface crystallization of the apatite layer proportional to the duration of immersion in the SBF and the degradation rate of scaffolds were increased by increasing the TiO2 content. The osteoblast-like cells showed a high

  7. Composite Scaffolds Containing Silk Fibroin, Gelatin, and Hydroxyapatite for Bone Tissue Regeneration and 3D Cell Culturing.

    Science.gov (United States)

    Moisenovich, M M; Arkhipova, A Yu; Orlova, A A; Drutskaya, M S; Volkova, S V; Zacharov, S E; Agapov, I I; Kirpichnikov, M P

    2014-01-01

    Three-dimensional (3D) silk fibroin scaffolds were modified with one of the major bone tissue derivatives (nano-hydroxyapatite) and/or a collagen derivative (gelatin). Adhesion and proliferation of mouse embryonic fibroblasts (MEF) within the scaffold were increased after modification with either nano-hydroxyapatite or gelatin. However, a significant increase in MEF adhesion and proliferation was observed when both additives were introduced into the scaffold. Such modified composite scaffolds provide a new and better platform to study wound healing, bone and other tissue regeneration, as well as artificial organ bioengineering. This system can further be applied to establish experimental models to study cell-substrate interactions, cell migration and other complex processes, which may be difficult to address using the conventional two-dimensional culture systems.

  8. 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.

  9. Effect of nanofiber content on bone regeneration of silk fibroin/poly(ε-caprolactone) nano/microfibrous composite scaffolds.

    Science.gov (United States)

    Kim, Beom Su; Park, Ko Eun; Kim, Min Hee; You, Hyung Keun; Lee, Jun; Park, Won Ho

    2015-01-01

    The broad application of electrospun nanofibrous scaffolds in tissue engineering is limited by their small pore size, which has a negative influence on cell migration. This disadvantage could be significantly improved through the combination of nano- and microfibrous structure. To accomplish this, different nano/microfibrous scaffolds were produced by hybrid electrospinning, combining solution electrospinning with melt electrospinning, while varying the content of the nanofiber. The morphology of the silk fibroin (SF)/poly(ε-caprolactone) (PCL) nano/microfibrous composite scaffolds was investigated with field-emission scanning electron microscopy, while the mechanical and pore properties were assessed by measurement of tensile strength and mercury porosimetry. To assay cell proliferation, cell viability, and infiltration ability, human mesenchymal stem cells were seeded on the SF/PCL nano/microfibrous composite scaffolds. From in vivo tests, it was found that the bone-regenerating ability of SF/PCL nano/microfibrous composite scaffolds was closely associated with the nanofiber content in the composite scaffolds. In conclusion, this approach of controlling the nanofiber content in SF/PCL nano/microfibrous composite scaffolds could be useful in the design of novel scaffolds for tissue engineering.

  10. 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.

  11. Silk fibroin scaffolds with muscle-like elasticity support in vitro differentiation of human skeletal muscle cells.

    Science.gov (United States)

    Chaturvedi, Vishal; Naskar, Deboki; Kinnear, Beverley F; Grenik, Elizabeth; Dye, Danielle E; Grounds, Miranda D; Kundu, Subhas C; Coombe, Deirdre R

    2016-11-22

    Human adult skeletal muscle has a limited ability to regenerate after injury and therapeutic options for volumetric muscle loss are few. Technologies to enhance regeneration of tissues generally rely upon bioscaffolds to mimic aspects of the tissue extracellular matrix (ECM). In the present study, silk fibroins from four Lepidoptera (silkworm) species engineered into three-dimensional scaffolds were examined for their ability to support the differentiation of primary human skeletal muscle myoblasts. Human skeletal muscle myoblasts (HSMMs) adhered, spread and deposited extensive ECM on all the scaffolds, but immunofluorescence and quantitative polymerase chain reaction analysis of gene expression revealed that myotube formation occurred differently on the various scaffolds. Bombyx mori fibroin scaffolds supported formation of long, well-aligned myotubes, whereas on Antheraea mylitta fibroin scaffolds the myotubes were thicker and shorter. Myotubes were oriented in two perpendicular layers on Antheraea assamensis scaffolds, and scaffolds of Philosamia/Samia ricini (S. ricini) fibroin poorly supported myotube formation. These differences were not caused by fibroin composition per se, as HSMMs adhered to, proliferated on and formed striated myotubes on all four fibroins presented as two-dimensional fibroin films. The Young's modulus of A. mylitta and B. mori scaffolds mimicked that of normal skeletal muscle, but A. assamensis and S. ricini scaffolds were more flexible. The present study demonstrates that although myoblasts deposit matrix onto fibroin scaffolds and create a permissive environment for cell proliferation, a scaffold elasticity resembling that of normal muscle is required for optimal myotube length, alignment, and maturation. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.

  12. Preparation of electrospun silk fibroin fiber mats as bone scaffolds: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Meechaisue, Chidchanok [Department of Materials Technology, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Wutticharoenmongkol, Patcharaporn [Technological Center for Electrospun Fibers and The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok 10330 (Thailand); Waraput, Rujira [Department of Materials Technology, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Huangjing, Thanapol [Department of Materials Technology, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Ketbumrung, Nantana [Department of Materials Technology, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Pavasant, Prasit [Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330 (Thailand); Supaphol, Pitt [Technological Center for Electrospun Fibers and The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok 10330 (Thailand)

    2007-09-15

    In the present contribution, electrospinning (e-spinning) was used to fabricate ultra-fine fibers of silk fibroin (SF) from cocoons of indigenous Thai silkworms (Nang-Lai) and Chinese/Japanese hybrid silkworms (DOAE-7). The effects of solution concentration (i.e., 10-40% (w/v) in 85% (v/v) formic acid) and applied electrostatic field strength (EFS; 10, 15 and 20 kV/10 cm) on morphology and size of the electrospun (e-spun) SF products were investigated by scanning electron microscopy. The average diameter of the resulting e-spun SF fibers was found to increase with an increase in both the solution concentration and the EFS value. Specifically, the average diameter of the e-spun SF fibers from Nang-Lai SF solutions ranged between 217 and 610 nm, while that of the fibers from DOAE-7 SF solutions ranged between 183 and 810 nm. The potential for use of the e-spun SF fiber mats as bone scaffolds was assessed with mouse osteoblast-like cells (MC3T3-E1) in which the cells appeared to adhere and proliferate well on their surface.

  13. 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.

  14. Silk fibroin/sodium alginate composite nano-fibrous scaffold prepared through thermally induced phase-separation (TIPS) method for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haiping, E-mail: zhp9810_a@163.com; Liu, Xiaotian, E-mail: xtianliu@126.com; Yang, Mingying, E-mail: yangm@zju.edu.cn; Zhu, Liangjun, E-mail: ljzhu@zju.edu.cn

    2015-10-01

    To mimic the natural fibrous structure of the tissue extracellular matrix, a nano-fibrous silk fibroin (SF)/sodium alginate (SA) composite scaffold was fabricated by a thermally-induced phase-separation method. The effects of SF/SA ratio on the structure and the porosity of the composite scaffolds were examined. Scanning electron microscopy and porosity results showed that the 5SF/1SA and 3SF/1SA scaffolds possessed an excellent nano-fibrous structure and a porosity of more than 90%. Fourier transform infrared, X-ray diffraction, and differential scanning calorimetry results indicated the physical interaction between SF and SA molecules and their good compatibility in the 5SF/1SA and 3SF/1SA scaffolds, whereas they showed less compatibility in the 1SF/1SA scaffold. Cell culture results showed that MG-63 cells can attach and grow well on the surface of the SF/SA scaffolds. The nano-fibrous SF/SA scaffold can be potentially used in tissue engineering. - Highlights: • We fabricate a nano-fibrous silk fibroin (SF)/sodium alginate (SA) composite scaffold. • The scaffold was prepared through a thermally induced phase separation method. • SF molecules are physically interacted with SA molecules. • Good molecular compatibility can be found in 5SF/1SA and 3SF/1SA scaffolds. • The nano-fibrous SF/SA scaffold is biocompatible.

  15. The Use of Silk as a Scaffold for Mature, Sustainable Unilocular Adipose 3D Tissue Engineered Systems.

    Science.gov (United States)

    Abbott, Rosalyn D; Wang, Rebecca Y; Reagan, Michaela R; Chen, Ying; Borowsky, Francis E; Zieba, Adam; Marra, Kacey G; Rubin, J Peter; Ghobrial, Irene M; Kaplan, David L

    2016-07-01

    There is a critical need for monitoring physiologically relevant, sustainable, human adipose tissues in vitro to gain new insights into metabolic diseases. To support long-term culture, a 3D silk scaffold assisted culture system is developed that maintains mature unilocular adipocytes ex vivo in coculture with preadipocytes, endothelial cells, and smooth muscle cells obtained from small volumes of liquefied adipose samples. Without the silk scaffold, adipose tissue explants cannot be sustained in long-term culture (3 months) due to their fragility. Adjustments to media components are used to tune lipid metabolism and proliferation, in addition to responsiveness to an inflammatory stimulus. Interestingly, patient specific responses to TNFα stimulation are observed, providing a proof-of-concept translational technique for patient specific disease modeling in the future. In summary, this novel 3D scaffold assisted approach is required for establishing physiologically relevant, sustainable, human adipose tissue systems from small volumes of lipoaspirate, making this methodology of great value to studies of metabolism, adipokine-driven diseases, and other diseases where the roles of adipocytes are only now becoming uncovered.

  16. Bladder tissue regeneration using acellular bi-layer silk scaffolds in a large animal model of augmentation cystoplasty.

    Science.gov (United States)

    Tu, Duong D; Chung, Yeun Goo; Gil, Eun Seok; Seth, Abhishek; Franck, Debra; Cristofaro, Vivian; Sullivan, Maryrose P; Di Vizio, Dolores; Gomez, Pablo; Adam, Rosalyn M; Kaplan, David L; Estrada, Carlos R; Mauney, Joshua R

    2013-11-01

    Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a porcine model of augmentation cystoplasty. Two bi-layer matrix configurations were fabricated by solvent-casting/salt leaching either alone (Group 1) or in combination with silk film casting (Group 2) to yield porous foams buttressed by heterogeneous surface pore occlusions or homogenous silk films, respectively. Bladder augmentation was performed with each scaffold group (6 × 6 cm(2)) in juvenile Yorkshire swine for 3 m of implantation. Augmented animals exhibited high rates of survival (Group 1: 5/6, 83%; Group 2: 4/4, 100%) and voluntary voiding over the course of the study period. Urodynamic evaluations demonstrated mean increases in bladder capacity over pre-operative levels (Group 1: 277%; Group 2: 153%) which exceeded nonsurgical control gains (144%) encountered due to animal growth.In addition, animals augmented with both matrix configurations displayed increases in bladder compliance over pre-operative levels(Group 1: 357%; Group 2: 338%) similar to growth-related elevations observed in non-surgical controls (354%) [corrected]. Gross tissue evaluations revealed that both matrix configurations supported extensive de novo tissue formation throughout the entire original implantation site which exhibited ultimate tensile strength similar to nonsurgical counterparts. Histological and immunohistochemical analyses showed that both implant groups promoted comparable extents of smooth muscle regeneration and contractile protein (α-smooth muscle actin and SM22α) expression within defect sites similar to controls. Parallel evaluations demonstrated the formation of a transitional, multi-layered urothelium with prominent cytokeratin, uroplakin, and p63 protein expression in both matrix groups. De novo innervation and vascularization processes were evident in all regenerated tissues indicated by synaptophysin-positive neuronal

  17. 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.

  18. Investigation of silk fibroin nanoparticle-decorated poly(l-lactic acid) composite scaffolds for osteoblast growth and differentiation

    Science.gov (United States)

    Chen, Biao-Qi; Kankala, Ranjith Kumar; Chen, Ai-Zheng; Yang, Ding-Zhu; Cheng, Xiao-Xia; Jiang, Ni-Na; Zhu, Kai; Wang, Shi-Bin

    2017-01-01

    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. PMID:28331312

  19. Mechano growth factor (MGF) and transforming growth factor (TGF)-β3 functionalized silk scaffolds enhance articular hyaline cartilage regeneration in rabbit model.

    Science.gov (United States)

    Luo, Ziwei; Jiang, Li; Xu, Yan; Li, Haibin; Xu, Wei; Wu, Shuangchi; Wang, Yuanliang; Tang, Zhenyu; Lv, Yonggang; Yang, Li

    2015-06-01

    Damaged cartilage has poor self-healing ability and usually progresses to scar or fibrocartilaginous tissue, and finally degenerates to osteoarthritis (OA). Here we demonstrated that one of alternative isoforms of IGF-1, mechano growth factor (MGF) acted synergistically with transforming growth factor β3 (TGF-β3) embedded in silk fibroin scaffolds to induce chemotactic homing and chondrogenic differentiation of mesenchymal stem cells (MSCs). Combination of MGF and TGF-β3 significantly increased cell recruitment up to 1.8 times and 2 times higher than TGF-β3 did in vitro and in vivo. Moreover, MGF increased Collagen II and aggrecan secretion of TGF-β3 induced hMSCs chondrogenesis, but decreased Collagen I in vitro. Silk fibroin (SF) scaffolds have been widely used for tissue engineering, and we showed that methanol treated pured SF scaffolds were porous, similar to compressive module of native cartilage, slow degradation rate and excellent drug released curves. At 7 days after subcutaneous implantation, TGF-β3 and MGF functionalized silk fibroin scaffolds (STM) recruited more CD29+/CD44+cells (Pcartilage-like extracellular matrix and less fibrillar collagen were detected in STM scaffolds than that in TGF-β3 modified scaffolds (ST) at 2 months after subcutaneous implantation. When implanted into articular joints in a rabbit osteochondral defect model, STM scaffolds showed the best integration into host tissues, similar architecture and collagen organization to native hyaline cartilage, as evidenced by immunostaining of aggrecan, collagen II and collagen I, as well as Safranin O and Masson's trichrome staining, and histological evalution based on the modified O'Driscoll histological scoring system (Pcartilage regeneration. This study demonstrated that TGF-β3 and MGF functionalized silk fibroin scaffolds enhanced endogenous stem cell recruitment and facilitated in situ articular cartilage regeneration, thus providing a novel strategy for cartilage repair

  20. 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.

  1. Improved hemocompatibility and endothelialization of vascular grafts by covalent immobilization of sulfated silk fibroin on poly(lactic-co-glycolic acid) scaffolds.

    Science.gov (United States)

    Liu, Haifeng; Li, Xiaoming; Niu, Xufeng; Zhou, Gang; Li, Ping; Fan, Yubo

    2011-08-08

    Endothelialization of vascular grafts prior to implantation has been investigated widely to enhance biocompatibility and antithrombogenicity. Thrombosis of artificial vessels is typically caused by platelet adhesion and agglomeration following endothelial cells detachment when exposed to the shear stress of blood circulation. The present study thus aimed at preventing platelet adhesion and aggregation onto biomaterials before the endothelial confluence is fully achieved. We report this modification of poly(lactic-co-glycolic acid) (PLGA) scaffolds, both to impart hemocompatibility to prevent platelet adhesion and aggregation before the endothelial confluence is fully achieved and to support EC growth to accelerate endothelialization. The modification was achieved by covalent immobilization of sulfated silk fibroin on PLGA scaffolds using γ irradiation. Using phosphate-buffered saline (PBS) as an aging medium, it was demonstrated that the scaffolds prepared by γ irradiation had a good retention of sulfated silk fibroin. The systematic in vitro hemocompatibility evaluation revealed that sulfated silk fibroin covalently immobilized PLGA (S-PLGA) scaffolds-reduced platelet adhesion and activation, prolonged whole blood clotting time, activated partial thromboplastin time (APTT), thrombin time (TT), and prothrombin time (PT). To evaluate further in vitro cytocompatibility of the scaffolds, we seeded vascular ECs on the scaffolds and cultured them for 2 weeks. The ECs were seen to attach and proliferate well on S-PLGA scaffolds, forming cell aggregates that gradually increased in size and fused with adjacent cell aggregates to form a monolayer covering the scaffold surface. Moreover, it was demonstrated through the gene transcript levels and the protein expressions of EC-specific markers that the cell functions of ECs on S-PLGA scaffolds were better preserved than those on PLGA scaffolds. Therefore, this study has described the generation of a vascular graft that

  2. Reconstruction of a hard connective tissue utilizing a pressed silk sheet and type-I collagen as the scaffold for fibroblasts.

    Science.gov (United States)

    Takezawa, Toshiaki; Ozaki, Katsuyuki; Takabayashi, Chiyuki

    2007-06-01

    A pressed silk sheet is a new biomaterial composed of a network of numerous cocoon filaments and having excellent mechanical strength and shape stability compared to a cotton-gauze sheet. To reconstruct a hard connective tissue using the silk sheet and type-I collagen as the scaffold for fibroblasts, three different three-dimensional floating culture systems were designed. "On sheet" system: fibroblasts were seeded on the silk sheet coated with collagen and the cell-attached sheet was cultured. "In gel" system: fibroblasts and the silk sheet were co-embedded in a collagen gel and the gel was cultured. "On vitrigel" system: fibroblasts were seeded on both sides of a collagen vitrigel involving the silk sheet and the vitrigel was cultured. The fibroblasts in all culture systems grew and formed disk-shaped connective tissue models involving the silk sheet by 14 days of culture. The "on sheet" and "on vitrigel" models retained a maximum elastic load of about 23 kgf and an ultimate tensile load of about 3.6 kgf, which were almost the same as for the individual silk sheet. However, the "in gel" system showed a low value for the tensile load. Cell damage following application of mechanical stress was lowest in the "on vitrigel" system. These data demonstrated the advantage of the "on vitrigel" system in reconstructing hard connective tissues. Such a novel culture method would contribute to a regenerative medicine for the failure of ligaments, tendons, and other connective tissues.

  3. 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.

    Science.gov (United States)

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

    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 417.65MPa and tensile strength 180.36MPa. 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.

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

    Science.gov (United States)

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

    2016-01-01

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

  5. 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

  6. 蚕丝磷酸钙涂层支架的制备和性能%The preparation and properties of silk fibroin /CaP scaffold

    Institute of Scientific and Technical Information of China (English)

    张珂; 张欣; 王淑敏; 俞立英

    2012-01-01

    Objective: To improve bone formation by mineralizing silk fibroin scaffold with calcium phosphate. Methods: Silk fibroin was immerged into calcium phosphate solution, and then mineralized on its surface using hydrothermal method. The characteristics of silk fibroin surface-modified were measured by scanning electron microscopy ( SEM ) , energy dispersive X-ray microanalysis, X-ray diffraction and Fourier transform infrared spectroscopy. Results: SEM indicated that the surface of silk fibroin was mostly coated by calcium phosphate. The patterns of silk fibroin surface-modified were not changed after immerging in solution, and carbonate apatite distributed on its surface. Conclusions: As a natural material, the silk fibroin possesses good biocompatibility. Silk fibroin/ CaP composite as scaffold material is a promising biomaterial.%目的:通过对蚕丝表面进行磷酸钙涂层,从而增加其成骨效果.方法:将脱胶后的蚕丝放入磷酸钙溶液中,用水热法对蚕丝表面进行矿化,运用扫描电镜、能谱分析仪、X线衍射仪、傅立叶红外对表面改良的蚕丝进行理化性能检测.结果:磷酸钙表面改良处理后磷酸钙均匀涂布于蚕丝表面,矿化蚕丝初始形态并未发生明显改变,表面存在磷酸灰石成分.结论:蚕丝作为一种天然生物纤维,具有良好的生物相容性.经磷酸钙涂层的蚕丝,作为组织工程支架材料具有广阔的发展前景.

  7. 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.

  8. Synergistic effect of exogeneous and endogeneous electrostimulation on osteogenic differentiation of human mesenchymal stem cells seeded on silk scaffolds.

    Science.gov (United States)

    Çakmak, Anıl S; Çakmak, Soner; White, James D; Raja, Waseem K; Kim, Kyungsook; Yiğit, Sezin; Kaplan, David L; Gümüşderelioğlu, Menemşe

    2016-04-01

    Bioelectrical regulation of bone fracture healing is important for many cellular events such as proliferation, migration, and differentiation. The aim of this study was to investigate the osteogenic differentiation potential of human mesenchymal stem cells (hMSCs) cultivated on silk scaffolds in response to different modes of electrostimulation (e.g., exogeneous and/or endogeneous). Endogeneous electrophysiology was altered through the use of monensin (10 nM) and glibenclamide (10 μM), along with external electrostimulation (60 kHz; 100-500 mV). Monensin enhanced the expression of early osteogenic markers such as alkaline phosphatase (ALP) and runt-related transcription factor 2 (RUNX-2). When exogeneous electrostimulation was combined with glibenclamide, more mature osteogenic marker upregulation based on bone sialoprotein expression (BSP) and mineralization was found. These results suggest the potential to exploit both exogeneous and endogeneous biophysical control of cell functions towards tissue-specific goals.

  9. Acellular bi-layer silk fibroin scaffolds support functional tissue regeneration in a rat model of onlay esophagoplasty.

    Science.gov (United States)

    Algarrahi, Khalid; Franck, Debra; Ghezzi, Chiara E; Cristofaro, Vivian; Yang, Xuehui; Sullivan, Maryrose P; Chung, Yeun Goo; Affas, Saif; Jennings, Russell; Kaplan, David L; Estrada, Carlos R; Mauney, Joshua R

    2015-06-01

    Surgical management of long-gap esophageal defects with autologous gastrointestinal tissues is frequently associated with adverse complications including organ dysmotility, dysphagia, and donor site morbidity. In order to develop alternative graft options, bi-layer silk fibroin (SF) scaffolds were investigated for their potential to support functional tissue regeneration in a rodent model of esophageal repair. Onlay esophagoplasty was performed with SF matrices (N = 40) in adult rats for up to 2 m of implantation. Parallel groups consisted of animals implanted with small intestinal submucosa (SIS) scaffolds (N = 22) or sham controls receiving esophagotomy alone (N = 20). Sham controls exhibited a 100% survival rate while rats implanted with SF and SIS scaffolds displayed respective survival rates of 93% and 91% prior to scheduled euthanasia. Animals in each experimental group were capable of solid food consumption following a 3 d post-op liquid diet and demonstrated similar degrees of weight gain throughout the study period. End-point μ-computed tomography at 2 m post-op revealed no evidence of contrast extravasation, fistulas, strictures, or diverticula in any of the implant groups. Ex vivo tissue bath studies demonstrated that reconstructed esophageal conduits supported by both SF and SIS scaffolds displayed contractile responses to carbachol, KCl and electrical field stimulation while isoproterenol produced tissue relaxation. Histological (Masson's trichrome and hematoxylin and eosin) and immunohistochemical (IHC) evaluations demonstrated both implant groups produced de novo formation of skeletal and smooth muscle bundles positive for contractile protein expression [fast myosin heavy chain (MY32) and α-smooth muscle actin (α-SMA)] within the graft site. However, SF matrices promoted a significant 4-fold increase in MY32+ skeletal muscle and a 2-fold gain in α-SMA+ smooth muscle in comparison to the SIS cohort as determined by histomorphometric

  10. 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.

  11. The promotion of osteochondral repair by combined intra-articular injection of parathyroid hormone-related protein and implantation of a bi-layer collagen-silk scaffold.

    Science.gov (United States)

    Zhang, Wei; Chen, Jialin; Tao, Jiadong; Hu, Changchang; Chen, Longkun; Zhao, Hongshi; Xu, Guowei; Heng, Boon C; Ouyang, Hong Wei

    2013-08-01

    The repair of osteochondral defects can be enhanced with scaffolds but is often accompanied with undesirable terminal differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Parathyroid hormone-related protein (PTHrP) has been shown to inhibit aberrant differentiation, but administration at inappropriate time points would have adverse effects on chondrogenesis. This study aims to develop an effective tissue engineering strategy by combining PTHrP and collagen-silk scaffold for osteochondral defect repair. The underlying mechanisms of the synergistic effect of combining PTHrP administration with collagen-silk scaffold implantation for rabbit knee joint osteochondral defect repair were investigated. In vitro studies showed that PTHrP treatment significantly reduced Alizarin Red staining and expression of terminal differentiation-related markers. This is achieved in part through blocking activation of the canonical Wnt/β-catenin signaling pathway. For the in vivo repair study, intra-articular injection of PTHrP was carried out at three different time windows (4-6, 7-9 and 10-12 weeks) together with implantation of a bi-layer collagen-silk scaffold. Defects treated with PTHrP at the 4-6 weeks time window exhibited better regeneration (reconstitution of cartilage and subchondral bone) with minimal terminal differentiation (hypertrophy, ossification and matrix degradation), as well as enhanced chondrogenesis (cell shape, Col2 and GAG accumulation) compared with treatment at other time windows. Furthermore, the timing of PTHrP administration also influenced PTHrP receptor expression, thus affecting the treatment outcome. Our results demonstrated that intra-articular injection of PTHrP at 4-6 weeks post-injury together with collagen-silk scaffold implantation is an effective strategy for inhibiting terminal differentiation and enhancing chondrogenesis, thus improving cartilage repair and regeneration in a rabbit model. Copyright © 2013 Elsevier Ltd. All

  12. Tailoring the properties and functions of phosphate/silk/Ag/chitosan scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Fattah, Wafa I., E-mail: nrcfifi@yahoo.com [National Research Centre, Biomaterials Department, Elbehoos St. Dokki, Giza (Egypt); Sallam, Abdel Sattar M., E-mail: ab_m_sallam@yahoo.com [Faculty of Science, Physics Department, Ain Shams University, Cairo (Egypt); Diab, A.M., E-mail: amdiabdr55@yahoo.com [High Institute of Engineering, Physics Department, El-Shorouk Academy, Cairo (Egypt); Ali, Ghareib W., E-mail: wafaa_ghareeeb@yahoo.com [National Research Centre, Biomaterials Department, Elbehoos St. Dokki, Giza (Egypt)

    2015-09-01

    Two novel silk composites of phosphatic phases with nanosilver/chitosan having enhanced biocompatibility were achieved. Hydroxyapatite and octa calcium phosphates were synthesized in situ within silk fibroin/chitosan/nanosilver composites recently studied. Thermo-gravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) verified their thermal behavior. The structural aspects were characterized applying X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM) with EDAX. Additionally X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared spectroscopy (FTIR) were applied. Mercury porosimeter was used to verify the pore size distribution. The in vitro degradation was followed in D-MEM for 48 h in a cumulative manner for five successive periods. Biochemical analyses of Ca, P and total protein using relevant chemical kits and atomic absorption for silver were performed. ANOVA statistics was carried out. Phosphatic crystalline phases along with the presence of silk, chitosan and nano-silver were developed. The diameters of hydroxyapatite and octa calcium phosphate particles were ~ 8–17 nm and 15–22 nm respectively. Comparatively higher degradation of Octa composite possessing higher porosity proved in turn more osteoinduction with in situ apatitic development. - Highlights: • A bottom–up approach controlled the achieved in situ configurations. • The calculated (CI){sub XDR} and (CI){sub FTIR} for both phases are highly conformable. • Post-immersion trimodal pore system was achieved in OCP composite. • Silver nanoparticle inclusion expected to enhance composite bactericidal activity.

  13. 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

  14. A three-dimensional multiporous fibrous scaffold fabricated with regenerated spider silk protein/poly(l-lactic acid) for tissue engineering.

    Science.gov (United States)

    Yu, Qiaozhen; Sun, Chengjun

    2015-02-01

    An axially aligned three-dimensional (3-D) fibrous scaffold was fabricated with regenerated spider silk protein (RSSP)/poly (l-lactic acid) (PLLA) through electrospinning and post treatment. The morphology, mechanical and degradation properties of the scaffold were controlled through the weight ratio of RSSP to PLLA, the thickness of the scaffold and the treatment time. The scaffold with a weight ratio of 2:3 (RSSP:PLLA) had a nanoleaves-on-nanofibers hierarchical nanostructure; the length and thickness of the nanoleaves were about 400 and 30 nm, respectively. The holes of the scaffolds ranged from hundreds of nanometers to several microns. The scaffold showed an ideal mechanical property that it was stiff when dry, but became soft once hydrated in the culture medium. Its degradation rate was very slow in the first 2 months, and then accelerated in the following 2 months. The pH values of the degradation mediums of all the samples remained in the range of 7.40-7.12 during degradation for 6 months. It had good biocompatibility with PC 12 cells. The aligned hierarchical nanostructure could guide the directions of the axon extension. This scaffold has a potential application in Tissue Engineering and controlled release. This study provides a method to produce synthetic or natural biodegradable polymer scaffold with tailored morphology, mechanical, and degradation properties.

  15. Experimental bladder regeneration using a poly-l-lactide/silk fibroin scaffold seeded with nanoparticle-labeled allogenic bone marrow stromal cells.

    Science.gov (United States)

    Yudintceva, Natalia M; Nashchekina, Yulia A; Blinova, Miralda I; Orlova, Nadezhda V; Muraviov, Alexandr N; Vinogradova, Tatiana I; Sheykhov, Magomed G; Shapkova, Elena Y; Emeljannikov, Dmitriy V; Yablonskii, Petr K; Samusenko, Igor A; Mikhrina, Anastasiya L; Pakhomov, Artem V; Shevtsov, Maxim A

    In the present study, a poly-l-lactide/silk fibroin (PL-SF) bilayer scaffold seeded with allogenic bone marrow stromal cells (BMSCs) was investigated as a potential approach for bladder tissue engineering in a model of partial bladder wall cystectomy in rabbits. The inner porous layer of the scaffold produced from silk fibroin was designed to promote cell proliferation and the outer layer produced from poly-l-lactic acid to serve as a waterproof barrier. To compare the feasibility and efficacy of BMSC application in the reconstruction of bladder defects, 12 adult male rabbits were divided into experimental and control groups (six animals each) that received a scaffold seeded with BMSCs or an acellular one, respectively. For BMSC tracking in the graft in in vivo studies using magnetic resonance imaging, cells were labeled with superparamagnetic iron oxide nanoparticles. In vitro studies demonstrated high intracellular incorporation of nanoparticles and the absence of a toxic influence on BMSC viability and proliferation. Following implantation of the graft with BMSCs into the bladder, we observed integration of the scaffold with surrounding bladder tissues (as detected by magnetic resonance imaging). During the follow-up period of 12 weeks, labeled BMSCs resided in the implanted scaffold. The functional activity of the reconstructed bladder was confirmed by electromyography. Subsequent histological assay demonstrated enhanced biointegrative properties of the PL-SF scaffold with cells in comparison to the control graft, as related to complete regeneration of the smooth muscle and urothelium tissues in the implant. Confocal microscopy studies confirmed the presence of the superparamagnetic iron oxide nanoparticle-labeled BMSCs in newly formed bladder layers, thus indicating the role of stem cells in bladder regeneration. The results of this study demonstrate that application of a PL-SF scaffold seeded with allogenic BMSCs can enhance biointegration of the graft in

  16. Silk fibroin/sodium alginate composite nano-fibrous scaffold prepared through thermally induced phase-separation (TIPS) method for biomedical applications.

    Science.gov (United States)

    Zhang, Haiping; Liu, Xiaotian; Yang, Mingying; Zhu, Liangjun

    2015-10-01

    To mimic the natural fibrous structure of the tissue extracellular matrix, a nano-fibrous silk fibroin (SF)/sodium alginate (SA) composite scaffold was fabricated by a thermally-induced phase-separation method. The effects of SF/SA ratio on the structure and the porosity of the composite scaffolds were examined. Scanning electron microscopy and porosity results showed that the 5SF/1SA and 3SF/1SA scaffolds possessed an excellent nano-fibrous structure and a porosity of more than 90%. Fourier transform infrared, X-ray diffraction, and differential scanning calorimetry results indicated the physical interaction between SF and SA molecules and their good compatibility in the 5SF/1SA and 3SF/1SA scaffolds, whereas they showed less compatibility in the 1SF/1SA scaffold. Cell culture results showed that MG-63 cells can attach and grow well on the surface of the SF/SA scaffolds. The nano-fibrous SF/SA scaffold can be potentially used in tissue engineering.

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

    Science.gov (United States)

    Zhu, Bofan

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

  18. Scleraxis-overexpressed human embryonic stem cell-derived mesenchymal stem cells for tendon tissue engineering with knitted silk-collagen scaffold.

    Science.gov (United States)

    Chen, Xiao; Yin, Zi; Chen, Jia-Lin; Liu, Huan-Huan; Shen, Wei-Liang; Fang, Zhi; Zhu, Ting; Ji, Junfeng; Ouyang, Hong-Wei; Zou, Xiao-Hui

    2014-06-01

    Despite our previous study that demonstrates that human embryonic stem cells (hESCs) can be used as seed cells for tendon tissue engineering after stepwise induction, suboptimal tendon regeneration implies that a new strategy needs to be developed for tendon repair. We investigated whether overexpression of the tendon-specific transcription factor scleraxis (SCX) in hESC-derived mesenchymal stem cells (hESC-MSCs) together with knitted silk-collagen sponge scaffold could promote tendon regeneration. hESCs were initially differentiated into MSCs and then engineered with scleraxis (SCX+hESC-MSCs). Engineered tendons were constructed with SCX+hESC-MSCs and a knitted silk-collagen sponge scaffold and then mechanical stress was applied. SCX elevated tendon gene expression in hESC-MSCs and concomitantly attenuated their adipogenic and chondrogenic potential. Mechanical stress further augmented the expression of tendon-specific genes in SCX+hESC-MSC-engineered tendon. Moreover, in vivo mechanical stimulation promoted the alignment of cells and increased the diameter of collagen fibers after ectopic transplantation. In the in vivo tendon repair model, the SCX+hESC-MSC-engineered tendon enhanced the regeneration process as shown by histological scores and superior mechanical performance compared with control cells, especially at early stages. Our study offers new evidence concerning the roles of SCX in tendon differentiation and regeneration. We demonstrated a novel strategy of combining hESCs, genetic engineering, and tissue-engineering principles for tendon regeneration, which are important for the future application of hESCs and silk scaffolds for tendon repair.

  19. Time-dependent bladder tissue regeneration using bilayer bladder acellular matrix graft-silk fibroin scaffolds in a rat bladder augmentation model.

    Science.gov (United States)

    Zhao, Yang; He, Yi; Zhou, Zhe; Guo, Jian-hua; Wu, Jia-sheng; Zhang, Ming; Li, Wei; Zhou, Juan; Xiao, Dong-dong; Wang, Zhong; Sun, Kang; Zhu, Ying-jian; Lu, Mu-jun

    2015-09-01

    With advances in tissue engineering, various synthetic and natural biomaterials have been widely used in tissue regeneration of the urinary bladder in rat models. However, reconstructive procedures remain insufficient due to the lack of appropriate scaffolding, which should provide a waterproof barrier function and support the needs of various cell types. To address these problems, we have developed a bilayer scaffold comprising a porous network (silk fibroin [SF]) and an underlying natural acellular matrix (bladder acellular matrix graft [BAMG]) and evaluated its feasibility and potential for bladder regeneration in a rat bladder augmentation model. Histological (hematoxylin and eosin and Masson's trichrome staining) and immunohistochemical analyses demonstrated that the bilayer BAMG-SF scaffold promoted smooth muscle, blood vessel, and nerve regeneration in a time-dependent manner. At 12weeks after implantation, bladders reconstructed with the BAMG-SF matrix displayed superior structural and functional properties without significant local tissue responses or systemic toxicity. These results demonstrated that the bilayer BAMG-SF scaffold may be a promising scaffold with good biocompatibility for bladder regeneration in the rat bladder augmentation model.

  20. A complex 3D human tissue culture system based on mammary stromal cells and silk scaffolds for modeling breast morphogenesis and function.

    Science.gov (United States)

    Wang, Xiuli; Sun, Lin; Maffini, Maricel V; Soto, Ana; Sonnenschein, Carlos; Kaplan, David L

    2010-05-01

    Epithelial-stromal interactions play a crucial role in normal embryonic development and carcinogenesis of the human breast while the underlying mechanisms of these events remain poorly understood. To address this issue, we constructed a physiologically relevant, three-dimensional (3D) culture surrogate of complex human breast tissue that included a tri-culture system made up of human mammary epithelial cells (MCF10A), human fibroblasts and adipocytes, i.e., the two dominant breast stromal cell types, in a Matrigel/collagen mixture on porous silk protein scaffolds. The presence of stromal cells inhibited MCF10A cell proliferation and induced both alveolar and ductal morphogenesis and enhanced casein expression. In contrast to the immature polarity exhibited by co-cultures with either fibroblasts or adipocytes, the alveolar structures formed by the tri-cultures exhibited proper polarity similar to that observed in breast tissue in vivo. Only alveolar structures with reverted polarity were observed in MCF10A monocultures. Consistent with their phenotypic appearance, more functional differentiation of epithelial cells was also observed in the tri-cultures, where casein alpha- and -beta mRNA expression was significantly increased. This in vitro tri-culture breast tissue system sustained on silk scaffold effectively represents a more physiologically relevant 3D microenvironment for mammary epithelial cells and stromal cells than either co-cultures or monocultures. This experimental model provides an important first step for bioengineering an informative human breast tissue system, with which to study normal breast morphogenesis and neoplastic transformation.

  1. Biocompatible Silk Noil-Based Three-Dimensional Carded-Needled Nonwoven Scaffolds Guide the Engineering of Novel Skin Connective Tissue.

    Science.gov (United States)

    Chiarini, Anna; Freddi, Giuliano; Liu, Daisong; Armato, Ubaldo; Dal Prà, Ilaria

    2016-08-01

    Retracting hypertrophic scars resulting from healed burn wounds heavily impact on the patients' life quality. Biomaterial scaffolds guiding burned-out skin regeneration could suppress or lessen scar retraction. Here we report a novel silk noil-based three-dimensional (3D) nonwoven scaffold produced by carding and needling with no formic acid exposure, which might improve burn healing. Once wetted, it displays human skin-like physical features and a high biocompatibility. Human keratinocyte-like cervical carcinoma C4-I cells seeded onto the carded-needled nonwovens in vitro quickly adhered to them, grew, and actively metabolized glutamine releasing lactate. As on plastic, they released no proinflammatory IL-1β, although secreting tumor necrosis factor-alpha, an inducer of the autocrine mitogen amphiregulin in such cells. Once grafted into interscapular subcutaneous tissue of mice, carded-needled nonwovens guided the afresh assembly of a connective tissue enveloping the fibroin microfibers and filling the interposed voids within 3 months. Fibroblasts and a few poly- or mononucleated macrophages populated the engineered tissue. Besides, its extracellular matrix contained thin sparse collagen fibrils and a newly formed vascular network whose endothelin-1-expressing endothelial cells grew first on the fibroin microfibrils and later expanded into the intervening matrix. Remarkably, no infiltrates of inflammatory leukocytes and no packed collagen fibers bundles among fibroin microfibers, no fibrous capsules at the grafts periphery, and hence no foreign body response was obtained at the end of 3 months of observation. Therefore, we posit that silk noil-based 3D carded-needled nonwoven scaffolds are tools for translational medicine studies as they could guide connective tissue regeneration at deep burn wounds averting scar retraction with good functional results.

  2. 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.

  3. A Silk Fibroin/Collagen Nerve Scaffold Seeded with a Co-Culture of Schwann Cells and Adipose-Derived Stem Cells for Sciatic Nerve Regeneration.

    Directory of Open Access Journals (Sweden)

    Yunqiang Xu

    Full Text Available As a promising alternative to autologous nerve grafts, tissue-engineered nerve grafts have been extensively studied as a way to bridge peripheral nerve defects and guide nerve regeneration. The main difference between autogenous nerve grafts and tissue-engineered nerve grafts is the regenerative microenvironment formed by the grafts. If an appropriate regenerative microenvironment is provided, the repair of a peripheral nerve is feasible. In this study, to mimic the body's natural regenerative microenvironment closely, we co-cultured Schwann cells (SCs and adipose-derived stem cells (ADSCs as seed cells and introduced them into a silk fibroin (SF/collagen scaffold to construct a tissue-engineered nerve conduit (TENC. Twelve weeks after the three different grafts (plain SF/collagen scaffold, TENC, and autograft were transplanted to bridge 1-cm long sciatic nerve defects in rats, a series of electrophysiological examinations and morphological analyses were performed to evaluate the effect of the tissue-engineered nerve grafts on peripheral nerve regeneration. The regenerative outcomes showed that the effect of treatment with TENCs was similar to that with autologous nerve grafts but superior to that with plain SF/collagen scaffolds. Meanwhile, no experimental animals had inflammation around the grafts. Based on this evidence, our findings suggest that the TENC we developed could improve the regenerative microenvironment and accelerate nerve regeneration compared to plain SF/collagen and may serve as a promising strategy for peripheral nerve repair.

  4. A Silk Fibroin/Collagen Nerve Scaffold Seeded with a Co-Culture of Schwann Cells and Adipose-Derived Stem Cells for Sciatic Nerve Regeneration.

    Science.gov (United States)

    Xu, Yunqiang; Zhang, Zhenhui; Chen, Xuyi; Li, Ruixin; Li, Dong; Feng, Shiqing

    2016-01-01

    As a promising alternative to autologous nerve grafts, tissue-engineered nerve grafts have been extensively studied as a way to bridge peripheral nerve defects and guide nerve regeneration. The main difference between autogenous nerve grafts and tissue-engineered nerve grafts is the regenerative microenvironment formed by the grafts. If an appropriate regenerative microenvironment is provided, the repair of a peripheral nerve is feasible. In this study, to mimic the body's natural regenerative microenvironment closely, we co-cultured Schwann cells (SCs) and adipose-derived stem cells (ADSCs) as seed cells and introduced them into a silk fibroin (SF)/collagen scaffold to construct a tissue-engineered nerve conduit (TENC). Twelve weeks after the three different grafts (plain SF/collagen scaffold, TENC, and autograft) were transplanted to bridge 1-cm long sciatic nerve defects in rats, a series of electrophysiological examinations and morphological analyses were performed to evaluate the effect of the tissue-engineered nerve grafts on peripheral nerve regeneration. The regenerative outcomes showed that the effect of treatment with TENCs was similar to that with autologous nerve grafts but superior to that with plain SF/collagen scaffolds. Meanwhile, no experimental animals had inflammation around the grafts. Based on this evidence, our findings suggest that the TENC we developed could improve the regenerative microenvironment and accelerate nerve regeneration compared to plain SF/collagen and may serve as a promising strategy for peripheral nerve repair.

  5. Tissue Regeneration: A Silk Road

    OpenAIRE

    Jao, Dave; Mou, Xiaoyang; Hu, Xiao

    2016-01-01

    Silk proteins are natural biopolymers that have extensive structural possibilities for chemical and mechanical modifications to facilitate novel properties, functions, and applications in the biomedical field. The versatile processability of silk fibroins (SF) into different forms such as gels, films, foams, membranes, scaffolds, and nanofibers makes it appealing in a variety of applications that require mechanically superior, biocompatible, biodegradable, and functionalizable biomaterials. T...

  6. Progress of electrospun silk fibroin based scaffolds for tissue engineering%静电纺丝素蛋白及其应用于组织工程的研究进展

    Institute of Scientific and Technical Information of China (English)

    黄继伟; 张锋; 左保齐

    2011-01-01

    The researches related to electrospinning of silk, including electrospim solvents, blends, and electrospin device are reviewed, and the application of electrospun silk fibroin based scaffolds in tissue engineering is introduced.%从丝素蛋白静电纺丝的溶剂开发、共混纺丝及纺丝装置3个方面回顾了丝素蛋白静电纺丝的研究进展,重点介绍了静电纺丝素蛋白微纳米纤维支架材料在组织工程领域的应用研究.

  7. 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

  8. 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

  9. Response of Dermal Fibroblasts to Biochemical and Physical Cues in Aligned Polycaprolactone/Silk Fibroin Nanofiber Scaffolds for Application in Tendon Tissue Engineering.

    Science.gov (United States)

    Chen, Chih-Hao; Chen, Shih-Hsien; Kuo, Chang-Yi; Li, Meng-Lun; Chen, Jyh-Ping

    2017-08-11

    Silk fibroin (SF) and fiber alignment were introduced into polycaprolactone (PCL)-based electrospun nanofibers as chemical and physical cues for tendon tissue engineering applications. The physicochemical properties of random PCL (RP) nanofibers, random PCL/SF (RPSF) nanofibers and aligned PCL/SF (APSF) nanofibers were characterized for fiber orientation and SF blending effects. An in vitro cell culture with rabbit dermal fibroblasts (RDFBs) on nanofibers indicated that SF promotes cell proliferation to a higher extent than fiber alignment. Cells aligned in the direction of fiber axes could be confirmed through scanning electron microscopy (SEM) observation and cytoskeleton staining. The quantitative real-time polymerase chain reaction (qRT-PCR) experiments indicated up-regulated gene expression of tendon marker proteins (type I collagen (Col I), fibronectin and biglycan) on APSF nanofibers and tendon reconstruction was confirmed from Col III gene expression. Animal experiments with Achilles tendon defect repairs in rabbits were carried out with RPSF and APSF scaffolds. The beneficial effects of fiber alignment were verified from histological and immunohistochemical staining, where cell migration and extracellular matrix protein deposition tend to stretch in a parallel direction along the axial direction of APSF nanofibers with enhanced Col I and tenascin C production. Biomechanical testing indicated the tensile stiffness and maximum load of cell-seeded APSF scaffolds were 60.2 and 81.3% of normal tendon values, respectively, which are significantly higher than cell-seeded RPSF or acellular APSF and RPSF scaffolds. These results suggest that APSF nanofiber scaffolds combined with RDFBs have the potential to repair the gap defects of Achilles tendons in vivo and to effectively restore the function and structure of tendons.

  10. 基因重组蛛丝蛋白-聚乙烯醇复合支架材料的制备%Preparation of recombinant spider silk protein-polyvinyl alcohol composite scaffold material

    Institute of Scientific and Technical Information of China (English)

    魏梅红; 涂桂云; 陈登龙; 李敏

    2008-01-01

    目的探讨致孔剂NaCl粒径和比例、变性剂和聚乙烯醇(PVA)等因素对基因重组蛛丝蛋白-PVA复合支架材料形态及性能的影响.方法基因重组蛛丝蛋白溶解于98%甲酸,采用冷冻干燥粒子滤沥法制备重组蛛丝蛋白-PVA复合多孔支架;采用扫描电子显微镜观察支架的形态;采用单纤维强力试验机测试支架机械性能.结果乙醇作变性剂制得的多孔支架力学性能较好,支架的断裂应力、断裂比强度均提高5倍以上,断裂伸长率可达12.21%.以粒径<500μm的NaCl为致孔剂制得的多孔支架力学性能较好.高分子材料PVA能明显改善重组蛛丝蛋白多孔支架的件能.结论重组蛛丝蛋白-PVA复合支架材料有望在组织工程领域得以应用.%Objective To investigate the effects of many factors such as porogen, denaturant and polyvinyl alcohol (PVA) polymer on the structure and properties of recombinant spider silk protein-PVA composite scaffold material. Methods The silk fibrous protein solution was prepared by dissolving the recombinant spider silk protein in 98% formic acid. Recombinant spider silk protein-PVA composite porous scaffolds were prepared by freeze-drying and particle-leaching method. Scanning electron microscope was used to observe the conformation of the scaffolds. Single strand strength testing machine was used to test the mechanical property of the scaffolds. Results Mechanical property of the scaffolds was better with ethanol as denaturant. Breaking stress and break specific tenacity enhanced by over 5 times. Breaking elongation ratio could reach 12.21%. Using NaCt ( ψ<500 μm) as porogen, or the introduction of PVA could improve the performances of porous scaffold evidently. Conclusion Recombinant spider silk protein-PVA composite porous scaffolds will have a prospective application in tissue engineering.

  11. 丝素蛋白支架的制备及其在组织工程中的应用%Preparation and Application of Silk Fibrion Scaffolds for Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    孔令玲; 李延报

    2013-01-01

    作为一种天然的纤维蛋白,蚕丝具有良好的力学性能、生物相容性和可降解性,这使其在生物医学方面的应用不断拓展.多孔支架能够为细胞的粘附和增殖提供有利的微环境,在重塑和修复组织的过程中起着至关重要的作用.本文综述了丝素蛋白支架的多种制备方法,如静电纺丝法、冷冻干燥法、沥除法和发泡法等,阐述了丝素蛋白支架的表面改性方法,总结了丝素蛋白支架在组织工程中的应用.%As a natural fibrous protein,silk fibroin has remarkable mechanical properties,biocompatibility and biodegradability,which makes it widely used in biomedical area.Porous scaffolds provide a favorable microenvironment for cell adhesion and proliferation and play a key role in the process of remodeling and repairing tissue.In this paper,a variety of preparation methods of silk fibroin scaffolds including electrospinning,freeze-drying,leaching and foaming.The surface modification of the silk fibroin scaffolds is described and the applications of silk fibroin scaffolds in tissue engineering are summarized.

  12. Functional silk: colored and luminescent.

    Science.gov (United States)

    Tansil, Natalia C; Koh, Leng Duei; Han, Ming-Yong

    2012-03-15

    Silkworm silk is among the most widely used natural fibers for textile and biomedical applications due to its extraordinary mechanical properties and superior biocompatibility. A number of physical and chemical processes have also been developed to reconstruct silk into various forms or to artificially produce silk-like materials. In addition to the direct use and the delicate replication of silk's natural structure and properties, there is a growing interest to introduce more new functionalities into silk while maintaining its advantageous intrinsic properties. In this review we assess various methods and their merits to produce functional silk, specifically those with color and luminescence, through post-processing steps as well as biological approaches. There is a highlight on intrinsically colored and luminescent silk produced directly from silkworms for a wide range of applications, and a discussion on the suitable molecular properties for being incorporated effectively into silk while it is being produced in the silk gland. With these understanding, a new generation of silk containing various functional materials (e.g., drugs, antibiotics and stimuli-sensitive dyes) would be produced for novel applications such as cancer therapy with controlled release feature, wound dressing with monitoring/sensing feature, tissue engineering scaffolds with antibacterial, anticoagulant or anti-inflammatory feature, and many others.

  13. Coculture of dorsal root ganglion neurons and differentiated human corneal stromal stem cells on silk-based scaffolds.

    Science.gov (United States)

    Wang, Siran; Ghezzi, Chiara E; White, James D; Kaplan, David L

    2015-10-01

    Corneal tissue displays the highest peripheral nerve density in the human body. Engineering of biomaterials to promote interactions between neurons and corneal tissue could provide tissue models for nerve/cornea development, platforms for drug screening, as well as innovative opportunities to regenerate cornea tissue. The focus of this study was to develop a coculture system for differentiated human corneal stromal stem cells (dhCSSCs) and dorsal root ganglion neurons (DRG) to mimic the human cornea tissue interactions. Axon extension, connectivity, and neuron cell viability were studied. DRG neurons developed longer axons when cocultured with dhCSSCs in comparison to neuron cultures alone. To assess the mechanism involved in the coculture response, nerve growth factors (NGF) secreted by dhCSSCs including NGF, brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF), and neurotrophin-3 were characterized with greater focus on BDNF secretion. DhCSSCs also secreted collagen type I, an extracellular matrix molecule favorable for neuronal outgrowth. This coculture system provides a slowly degrading silk matrix to study neuronal responses in concert with hCSSCs related to innervation of corneal tissue with utility toward human corneal nerve regeneration and associated diseases. © 2015 Wiley Periodicals, Inc.

  14. 丝素蛋白支架在骨组织工程中的应用进展%Synthesis and application progression of silk fibroin scaffold in bone tissue engineering

    Institute of Scientific and Technical Information of China (English)

    陈亮; 刘勇

    2016-01-01

    The essential factors of bone tissue engineering include seed cell,growth factor and scaffold material.The biological structure,biological function and preparation method of scaffold material,which is the key component in bone tissue engineering,have attracted our attention.An ideal scaffold material needs to have adequate mechanical strength,appropriate degradation speed,good biocompatibility,satisfactory availability,low price,et al.Common scaffold materials in bone tissue engineering mainly consist of inorganic matter,organic matter and natural derivatives.Silk fibroin which is extracted from silkworm protein fiber contains 18 kinds of amino acids.The glycine,alanine,serine are the main types in silk fibroin and its structure consisted of hydrogen bonding,hydrophobic bonding and crystalline region.Those special structures make it has good flexibility and tensile strength.Silk fibroin has other advantages incluing air permeability,moisture permeability and biodegradation.Besides silk fibroin with curing crystallization of diversification that easy to maintain biological affinity and form a special porous structure.Silk fibroin has good film and gel forming ability.Silk fibroin can bond with some other materials to further improve its physical and chemical properties.Silk fibroin can be formed into porous shape,membranous,gel and composite materials scaffold.The materials scaffold which based on silk fibroin has excellent mechanical performance,adjustable degradation speed,high biocompatibility and good osteogenesis performance,besides capability of loading cells,bioactive factors and drugs.In addition,silk fibroin which can be made into gel scaffold,porous scaffold,electrospinning fiber,and compound scaffold et al has three-dimensional porous and biological function for bone tissue engineering as a new choice and application prospect.%支架材料作为骨组织工程的核心部分,其生物结构、功能和制备方法引起众多关注.理想的支架材料

  15. 医用组织工程多孔丝素支架制备方法的进展%Advances in preparation of porous silk fibroin scaffolds for medical tissue engineering

    Institute of Scientific and Technical Information of China (English)

    廖银琳; 王卉; 张克勤

    2012-01-01

    Silk fibroin has been adopted as scaffolds materials for tissue engineering applications, due to its remarkable biocom-patibility, biodegradability and unique mechanical property. Various preparation methods of porous silk fibroin scaffolds are introduced, such as pore-forming agent method, freeze drying method, foaming method, electro-spinning method, nonwoven method and compression molding method and 3-D printing method, as well as their advantages and disadvantages.%丝素蛋白具有一定的生物降解性、良好的生物相容性及独特的机械性能等,适用于开发优良的医用组织工程支架材料.文中介绍了制备多孔丝素支架的各种方法:制孔剂法、冷冻干燥法、气体发泡法、静电纺丝法、无纺法、模压法和三维打印法等,并对其优缺点进行了分析.

  16. Fabrication and Biocompatibility of Electrospun Silk Biocomposites

    Science.gov (United States)

    Wei, Kai; Kim, Byoung-Suhk; Kim, Ick-Soo

    2011-01-01

    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. PMID:24957869

  17. SPIDER SILK

    Directory of Open Access Journals (Sweden)

    PORAV Viorica

    2014-05-01

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

  18. The effect of sterilization on silk fibroin biomaterial properties.

    Science.gov (United States)

    Rnjak-Kovacina, Jelena; DesRochers, Teresa M; Burke, Kelly A; Kaplan, David L

    2015-06-01

    The effects of common sterilization techniques on the physical and biological properties of lyophilized silk fibroin sponges are described. Sterile silk fibroin sponges were cast using a pre-sterilized silk fibroin solution under aseptic conditions or post-sterilized via autoclaving, γ radiation, dry heat, exposure to ethylene oxide, or hydrogen peroxide gas plasma. Low average molecular weight and low concentration silk fibroin solutions could be sterilized via autoclaving or filtration without significant loses of protein. However, autoclaving reduced the molecular weight distribution of the silk fibroin protein solution, and silk fibroin sponges cast from autoclaved silk fibroin were significantly stiffer compared to sponges cast from unsterilized or filtered silk fibroin. When silk fibroin sponges were sterilized post-casting, autoclaving increased scaffold stiffness, while decreasing scaffold degradation rate in vitro. In contrast, γ irradiation accelerated scaffold degradation rate. Exposure to ethylene oxide significantly decreased cell proliferation rate on silk fibroin sponges, which was rescued by leaching ethylene oxide into PBS prior to cell seeding.

  19. Spider silk gut: Development and characterization of a novel strong spider silk fiber

    Science.gov (United States)

    Jiang, Ping; Marí-Buyé, Núria; Madurga, Rodrigo; Arroyo-Hernández, María; Solanas, Concepción; Gañán, Alfonso; Daza, Rafael; Plaza, Gustavo R.; Guinea, Gustavo V.; Elices, Manuel; Cenis, José Luis; Pérez-Rigueiro, José

    2014-12-01

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much larger cross-sectional area of the former. In particular spider silk gut has a proper ground state to which the material can revert independently from its previous loading history by supercontraction. A larger cross-sectional area implies that spider silk gut outperforms the natural material in terms of the loads that the fiber can sustain. This property suggests that it could substitute conventional spider silk fibers in some intended uses, such as sutures and scaffolds in tissue engineering.

  20. Spider silk gut: development and characterization of a novel strong spider silk fiber.

    Science.gov (United States)

    Jiang, Ping; Marí-Buyé, Núria; Madurga, Rodrigo; Arroyo-Hernández, María; Solanas, Concepción; Gañán, Alfonso; Daza, Rafael; Plaza, Gustavo R; Guinea, Gustavo V; Elices, Manuel; Cenis, José Luis; Pérez-Rigueiro, José

    2014-12-05

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much larger cross-sectional area of the former. In particular spider silk gut has a proper ground state to which the material can revert independently from its previous loading history by supercontraction. A larger cross-sectional area implies that spider silk gut outperforms the natural material in terms of the loads that the fiber can sustain. This property suggests that it could substitute conventional spider silk fibers in some intended uses, such as sutures and scaffolds in tissue engineering.

  1. 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.

  2. COMPARATIVE ANALYSIS OF THREE-DIMENSIONAL NANOSTRUCTURE OF POROUS BIOCOMPATIBLE SCAFFOLDS MADE OF RECOMBINANT SPIDROIN AND SILK FIBROIN FOR REGENERATIVE MEDICINE

    Directory of Open Access Journals (Sweden)

    O. I. Agapova

    2015-01-01

    Full Text Available Aim. To perform a comparison of three-dimensional nanostructure of porous biocompatible scaffolds made of fibroin Bombix mori and recombinant spidroin rS1/9. Materials and methods. Three-dimensional porous scaffolds were produced by salt leaching technique. The comparison of biological characteristics of the scaffolds shows that adhesion and proliferation of mouse fibroblasts in vitro on these two types of scaffolds do not differ significantly. Comparative experiments in vivo show that regeneration of bone tissue of rats is faster with implantation of recombinant spidroin scaffolds. Three-dimensional nanostructure of scaffolds and interconnectivity of nanopores were studied with scanning probe nanotomography (SPNT to explain higher regenerative activity of spidroin-based scaffolds. Results. Significant differences were detected in the integral density and volume of pores: the integral density of nanopores detected on 2D AFM images is 46 μm–2    and calculated volume porosity is 24% in rS1/9-based scaffolds; in fibroin-based three-dimensional structures density of nanopores and calculated volume porosity were 2.4 μm–2  and 0.5%, respectively. Three-dimensional reconstruction system of nanopores and clusters of interconnected nanopores in rS1/9-based scaffolds showed that volume fraction of pores interconnected in percolation clusters is 35.3% of the total pore volume or 8.4% of the total scaffold volume. Conclusion. Scanning probe nanotomography method allows obtaining unique information about topology of micro – and nanopore systems of artificial biostructures. High regenerative activity of rS1/9-based scaffolds can be explained by higher nanoporosity of the scaffolds.

  3. Fabrication of duck's feet collagen-silk hybrid biomaterial for tissue engineering.

    Science.gov (United States)

    Kim, Soo Hyeon; Park, Hae Sang; Lee, Ok Joo; Chao, Janet Ren; Park, Hyun Jung; Lee, Jung Min; Ju, Hyung Woo; Moon, Bo Mi; Park, Ye Ri; Song, Jeong Eun; Khang, Gilson; Park, Chan Hum

    2016-04-01

    Collagen constituting the extracellular matrix has been widely used as biocompatible material for human use. In this study, we have selected duck's feet for extracting collagen. A simple method not utilizing harsh chemical had been employed to extract collagen from duck's feet. We fabricated duck's feet collagen/silk hybrid scaffold for the purpose of modifying the degradation rate of duck's feet collagen. This study suggests that extracted collagen from duck's feet is biocompatible and resembles collagen extracted from porcine which is commercially used. Duck's feet collagen is also economically feasible and it could therefore be a good candidate as a tissue engineering material. Further, addition of silk to fabricate a duck's feet collagen/silk hybrid scaffold could enhance the biostability of duck's feet collagen scaffold. Duck's feet collagen/silk scaffold increased the cell viability compared to silk alone. Animal studies also showed that duck's feet collagen/silk scaffold was more biocompatible than silk alone and more biostable than duck's feet or porcine collagen alone. Additionally, the results revealed that duck's feet collagen/silk hybrid scaffold had high porosity, cell infiltration and proliferation. We suggest that duck's feet collagen/silk hybrid scaffold could be used as a dermal substitution for full thickness skin defects.

  4. Recombinant spider silk proteins for applications in biomaterials.

    Science.gov (United States)

    Spiess, Kristina; Lammel, Andreas; Scheibel, Thomas

    2010-09-09

    Due to their extraordinary mechanical and biochemical properties, silks have long been in focus of research. In vivo, fibers are formed from silk proteins, in vitro, however, a variety of materials can be produced in addition to fibers including capsules, particles, films, foams, and gels. The versatility of silk proteins, along with their biocompatibility, biodegradability, and potential for processing in aqueous solution under ambient conditions make silk-based materials good candidates for biomedical applications such as drug delivery systems and scaffolds for tissue engineering. Here, we summarize recent progress in research employing recombinantly produced engineered spider silk proteins with a focus on the fundamentals of silk protein processing. We highlight recombinant spider silk films and particles as morphologies that represent model systems with adjustable material properties controlled by process parameters.

  5. Processing silk hydrogel and its applications in biomedical materials.

    Science.gov (United States)

    Wang, Hai-Yan; Zhang, Yu-Qing

    2015-01-01

    This review mainly introduces the types of silk hydrogels, their processing methods, and applications. There are various methods for hydrogel preparation, and many new processes are being developed for various applications. Silk hydrogels can be used in cartilage tissue engineering, drug release materials, 3D scaffolds for cells, and artificial skin, among other applications because of their porous structure and high porosity and the large surface area for growth, migration, adhesion and proliferation of cells that the hydrogels provide. All of these advantages have made silk hydrogels increasingly attractive. In addition, silk hydrogels have wide prospects for application in the field of biomedical materials.

  6. 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.

  7. Spider Silk as Guiding Biomaterial for Human Model Neurons

    Directory of Open Access Journals (Sweden)

    Frank Roloff

    2014-01-01

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

  8. Spider silk as guiding biomaterial for human model neurons.

    Science.gov (United States)

    Roloff, Frank; Strauß, Sarah; Vogt, Peter M; Bicker, Gerd; Radtke, Christine

    2014-01-01

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

  9. Silver nanoparticle containing silk fibroin bionanotextiles

    Science.gov (United States)

    Calamak, Semih; Aksoy, Eda Ayse; Erdogdu, Ceren; Sagıroglu, Meral; Ulubayram, Kezban

    2015-02-01

    Development of new generation bionanotextiles is an important growing field, and they have found applications as wound dressings, bandages, tissue scaffolds, etc. In this study, silver nanoparticle (AgNP) containing silk-based bionanotextiles were fabricated by electrospinning, and processing parameters were optimized and discussed in detail. AgNPs were in situ synthesized within fibroin nanofibers by UV reduction of silver ions to metallic silver. The influence of post-treatments via methanol treatment and glutaraldehyde (GA) vapor exhibited changes in the secondary structure of silk. Methanol treatment increased the tensile properties of fibers due to supported crystalline silk structure, while GA vapor promoted amorphous secondary structure. AgNP containing silk fibroin bionanotextiles had strong antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa.

  10. Silver nanoparticle containing silk fibroin bionanotextiles

    Energy Technology Data Exchange (ETDEWEB)

    Calamak, Semih; Aksoy, Eda Ayse [Hacettepe University, Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy (Turkey); Erdogdu, Ceren; Sagıroglu, Meral [Hacettepe University, Department of Pharmaceutical Microbiology, Faculty of Pharmacy (Turkey); Ulubayram, Kezban, E-mail: ukezban@hacettepe.edu.tr [Hacettepe University, Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy (Turkey)

    2015-02-15

    Development of new generation bionanotextiles is an important growing field, and they have found applications as wound dressings, bandages, tissue scaffolds, etc. In this study, silver nanoparticle (AgNP) containing silk-based bionanotextiles were fabricated by electrospinning, and processing parameters were optimized and discussed in detail. AgNPs were in situ synthesized within fibroin nanofibers by UV reduction of silver ions to metallic silver. The influence of post-treatments via methanol treatment and glutaraldehyde (GA) vapor exhibited changes in the secondary structure of silk. Methanol treatment increased the tensile properties of fibers due to supported crystalline silk structure, while GA vapor promoted amorphous secondary structure. AgNP containing silk fibroin bionanotextiles had strong antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa.

  11. Fabrication and characterization of Antheraea pernyi silk fibroin-blended P(LLA-CL) nanofibrous scaffolds for peripheral nerve tissue engineering

    Science.gov (United States)

    Wang, Juan; Sun, Binbin; Bhutto, Muhammad Aqeel; Zhu, Tonghe; Yu, Kui; Bao, Jiayu; Morsi, Yosry; El-Hamshary, Hany; El-Newehy, Mohamed; Mo, Xiumei

    2017-03-01

    Electrospun nanofibers have gained widespreading interest for tissue engineering application. In the present study, ApF/P(LLA-CL) nanofibrous scaffolds were fabricated via electrospinning. The feasibility of the material as tissue engineering nerve scaffold was investigated in vitro. The average diameter increased with decreasing the blend ratio of ApF to P(LLA-CL). Characterization of 13C NMR and FTIR clarified that there is no obvious chemical bond reaction between ApF and P(LLA-CL). The tensile strength and elongation at break increased with the content increase of P(LLA-CL). The surface hydrophilic property of nanofibrous scaffolds enhanced with the increased content of ApF. Cell viability studies with Schwann cells demonstrated that ApF/P(LLA-CL) blended nanofibrous scaffolds significantly promoted cell growth as compare to P(LLA-CL), especially when the weight ratio of ApF to P(LLA-CL) was 25:75. The present work provides a basis for further studies of this novel nanofibrous material (ApF/P(LLA-CL)) in peripheral nerve tissue repair or regeneration.

  12. Fabrication and characterization of Antheraea pernyi silk fibroin-blended P(LLA-CL) nanofibrous scaffolds for peripheral nerve tissue engineering

    Science.gov (United States)

    Wang, Juan; Sun, Binbin; Bhutto, Muhammad Aqeel; Zhu, Tonghe; Yu, Kui; Bao, Jiayu; Morsi, Yosry; El-Hamshary, Hany; El-Newehy, Mohamed; Mo, Xiumei

    2017-01-01

    Electrospun nanofibers have gained widespreading interest for tissue engineering application. In the present study, ApF/P(LLA-CL) nanofibrous scaffolds were fabricated via electrospinning. The feasibility of the material as tissue engineering nerve scaffold was investigated in vitro. The average diameter increased with decreasing the blend ratio of ApF to P(LLA-CL). Characterization of 13C NMR and FTIR clarified that there is no obvious chemical bond reaction between ApF and P(LLA-CL). The tensile strength and elongation at break increased with the content increase of P(LLA-CL). The surface hydrophilic property of nanofibrous scaffolds enhanced with the increased content of ApF. Cell viability studies with Schwann cells demonstrated that ApF/P(LLA-CL) blended nanofibrous scaffolds significantly promoted cell growth as compare to P(LLA-CL), especially when the weight ratio of ApF to P(LLA-CL) was 25:75. The present work provides a basis for further studies of this novel nanofibrous material (ApF/P(LLA-CL)) in peripheral nerve tissue repair or regeneration.

  13. Tissue Regeneration: A Silk Road

    Science.gov (United States)

    Jao, Dave; Mou, Xiaoyang; Hu, Xiao

    2016-01-01

    Silk proteins are natural biopolymers that have extensive structural possibilities for chemical and mechanical modifications to facilitate novel properties, functions, and applications in the biomedical field. The versatile processability of silk fibroins (SF) into different forms such as gels, films, foams, membranes, scaffolds, and nanofibers makes it appealing in a variety of applications that require mechanically superior, biocompatible, biodegradable, and functionalizable biomaterials. There is no doubt that nature is the world’s best biological engineer, with simple, exquisite but powerful designs that have inspired novel technologies. By understanding the surface interaction of silk materials with living cells, unique characteristics can be implemented through structural modifications, such as controllable wettability, high-strength adhesiveness, and reflectivity properties, suggesting its potential suitability for surgical, optical, and other biomedical applications. All of the interesting features of SF, such as tunable biodegradation, anti-bacterial properties, and mechanical properties combined with potential self-healing modifications, make it ideal for future tissue engineering applications. In this review, we first demonstrate the current understanding of the structures and mechanical properties of SF and the various functionalizations of SF matrices through chemical and physical manipulations. Then the diverse applications of SF architectures and scaffolds for different regenerative medicine will be discussed in detail, including their current applications in bone, eye, nerve, skin, tendon, ligament, and cartilage regeneration. PMID:27527229

  14. Tissue Regeneration: A Silk Road.

    Science.gov (United States)

    Jao, Dave; Mou, Xiaoyang; Hu, Xiao

    2016-01-01

    Silk proteins are natural biopolymers that have extensive structural possibilities for chemical and mechanical modifications to facilitate novel properties, functions, and applications in the biomedical field. The versatile processability of silk fibroins (SF) into different forms such as gels, films, foams, membranes, scaffolds, and nanofibers makes it appealing in a variety of applications that require mechanically superior, biocompatible, biodegradable, and functionalizable biomaterials. There is no doubt that nature is the world's best biological engineer, with simple, exquisite but powerful designs that have inspired novel technologies. By understanding the surface interaction of silk materials with living cells, unique characteristics can be implemented through structural modifications, such as controllable wettability, high-strength adhesiveness, and reflectivity properties, suggesting its potential suitability for surgical, optical, and other biomedical applications. All of the interesting features of SF, such as tunable biodegradation, anti-bacterial properties, and mechanical properties combined with potential self-healing modifications, make it ideal for future tissue engineering applications. In this review, we first demonstrate the current understanding of the structures and mechanical properties of SF and the various functionalizations of SF matrices through chemical and physical manipulations. Then the diverse applications of SF architectures and scaffolds for different regenerative medicine will be discussed in detail, including their current applications in bone, eye, nerve, skin, tendon, ligament, and cartilage regeneration.

  15. Experimental Study on Silk Protein- Three-dimensional Gelatin Scaffold and Compatibility of Liver Cells%蚕丝蛋白和明胶复合组织工程材料与肝细胞相容性的实验研究

    Institute of Scientific and Technical Information of China (English)

    徐丽莎; 刘文晶; 申少波; 杨照; 陈蕊蕊; 韩英; 尹芳; 时永全; 周新民

    2011-01-01

    Objective: To study the silk fibroin material's effect on proliferation of human normal hepatic cell line QZG,and to testify the cytocompatibility when blending of silk fibroin and gelatin into 3D scaffold. Methods:The activity of cell proliferation and relative growth rate (RGR) were assessed by MTT colorimetric assay and viable cell counting, The effect of silk protein materials on growth of cells was observed by scanning electron microscopy (SEM). Results: Human normal hepatic cell line QZG were cultivated in vitro directly on pure silk protein materials and silk fibroin/gelatin materials. Cells solidly adhered to the materials. The activity of cell proliferation on silk fibroin/gelatin materials was significantly more than that in the group of pure silk fibroin materials. The result of viable cell counting was compatible to MTT colorimetric assay. Conclusion:The silk fibroin materials together with gelatin has a good cytocompatibility with human normal hepatic cell line QZG. It will be useful in liver tissue engineering.%目的:研究蚕丝蛋白-明胶三维材料支架对人永生化肝细胞系QZG 贴附及增殖的影响.方法:采用四氮唑盐比色法(MTT)、细胞计数法检测QZG 细胞在纯蚕丝生物材料上与在蚕丝蛋白-明胶复合材料上的增殖情况,用扫描电镜观察QZG细胞在两种三维生物材料上的贴附与增殖情况.结果:QZG细胞可以在蚕丝蛋白生物材料贴附及增殖.在引入明胶的蚕丝蛋白材料上细胞贴附更紧密,增殖更明显.结论:蚕丝蛋白与明胶复合材料支架具有良好的细胞贴附性能.通过改进在肝组织工程应用方面将具有一定应用前景.

  16. 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

  17. Development of new smart materials and spinning systems inspired by natural silks and their applications

    Science.gov (United States)

    Cheng, Jie; Lee, Sang-Hoon

    2015-12-01

    Silks produced by spiders and silkworms are charming natural biological materials with highly optimized hierarchical structures and outstanding physicomechanical properties. The superior performance of silks relies on the integration of a unique protein sequence, a distinctive spinning process, and complex hierarchical structures. Silks have been prepared to form a variety of morphologies and are widely used in diverse applications, for example, in the textile industry, as drug delivery vehicles, and as tissue engineering scaffolds. This review presents an overview of the organization of natural silks, in which chemical and physical functions are optimized, as well as a range of new materials inspired by the desire to mimic natural silk structure and synthesis.

  18. Spider Webs and Silks.

    Science.gov (United States)

    Vollrath, Fritz

    1992-01-01

    Compares the attributes of the silk from spiders with those of the commercially harvested silk from silkworms. Discusses the evolution, design, and effectiveness of spider webs; the functional mechanics of the varieties of silk that can be produced by the same spider; and the composite, as well as molecular, structure of spider silk thread. (JJK)

  19. The Silk Saga

    Institute of Scientific and Technical Information of China (English)

    Feng Yuan

    2008-01-01

    @@ Silk,with a history of over five thousand years,plays an important part in the civilization of China and around the world.Aiming to promote the silk culture and industrial development,ana popularize the silk manufacturer brands in China,China Textile magazine specially set a column to introduce the well-known silk production bases in China.

  20. Manufacturing Ancient Imperial Silk

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    China was the first country in the world to develop silkworm breeding silk reeling, silk weaving, dying and embroidering. Located in the middle and lower reaches of the Yangtze River, Zhejiang Province has a long history of silk production. At the Qianshanyang Remains, which date back 4,800 years, silk fabrics were excavated. All rulers of past ages had special organizations responsible for

  1. Spider Webs and Silks.

    Science.gov (United States)

    Vollrath, Fritz

    1992-01-01

    Compares the attributes of the silk from spiders with those of the commercially harvested silk from silkworms. Discusses the evolution, design, and effectiveness of spider webs; the functional mechanics of the varieties of silk that can be produced by the same spider; and the composite, as well as molecular, structure of spider silk thread. (JJK)

  2. Functionalised Silk Fibres

    Science.gov (United States)

    2012-07-30

    method. We note that high levels of non-specific binding to silkworm silk have been reported in other laboratories (Lammel et al., 2011...are commonly used to induce ß-sheet formation in reconstituted silkworm silk and 16 result in water insensitive material. FTIR analysis...model for artificial honeybee silk. In contrast, hornet silk (Vespoidea) can be solubilised in lithium bromide (akin to silkworm silk). Therefore, the

  3. Biodegradation of Silk Biomaterials

    OpenAIRE

    Bochu Wang; Yang Cao

    2009-01-01

    Silk fibroin from the silkworm, Bombyx mori, has excellent properties such as biocompatibility, biodegradation, non-toxicity, adsorption properties, etc. As a kind of ideal biomaterial, silk fibroin has been widely used since it was first utilized for sutures a long time ago. The degradation behavior of silk biomaterials is obviously important for medical applications. This article will focus on silk-based biomaterials and review the degradation behaviors of silk materials.

  4. Effects of degumming conditions on electro-spinning rate of regenerated silk.

    Science.gov (United States)

    Yoon, Kyunghwan; Lee, Ha Ni; Ki, Chang Seok; Fang, Dufei; Hsiao, Benjamin S; Chu, Benjamin; Um, In Chul

    2013-10-01

    Electro-spun silk webs are potentially good candidates as tissue engineering scaffolds owing to their good bio- and cyto-compatibility. However, the low fabrication rate of electro-spun silk mats has been one of the obstacles in the mass production of such nanofibrous silk mats in applications to the biomedical field. In this study, the effects of degumming ratio and silk concentration on the electro-spinning process were investigated by using regenerated silk with different residual sericin contents and different silk concentrations in terms of the morphology and structure of the electro-spun silk web. The rate of production of electro-spun silk mats could be increased by approximately 5 fold at a degumming ratio of 19.5%. The electro-spinning rate of silk was affected by two main factors: (1) dope solution viscosity and (2) degumming ratio of silk. The conductivity of the silk dope solution, however, had little effects on the electro-spinning of regenerated silk. A constant spun fiber morphology was observed within the electro-spinning rate range (0.3-1.4 ml/h). Fourier transform infrared spectroscopy showed that partial β-sheet crystallization occurred during electro-spinning. The molecular conformation was relatively unaffected by the electro-spinning rate of silk.

  5. Preparation and characterization of collagen/silk fibroin composite scaffold incorporating TGF-β1 nanoparticles%载TGF-β1纳米粒的胶原/丝素蛋白复合支架的制备与表征

    Institute of Scientific and Technical Information of China (English)

    方哲翔; 王建华; 程娘梅; 张其清

    2016-01-01

    目的 构建一种载转化生长因子β1(TGF-β1)纳米粒的双层胶原/丝素蛋白复合支架.方法 制备载TGF-β1的壳聚糖-肝素(Ch-Hep)纳米粒,检测其形态、粒径、Zeta电位和包封率.制备不同胶原和丝素蛋白质量比(2∶8、3∶7、7∶3、8∶2、10∶0)的5种胶原/丝素蛋白复合材料,分别检测其吸水率、孔隙率、热水溶失率和生物相容性;选择其中2种综合性能良好的复合材料分别作为复合支架的疏松层和致密层,构建载TGF-β1纳米粒的双层胶原/丝素蛋白复合支架,观察其形态并进行体外释放动力学研究.结果 Ch-Hep纳米粒的平均粒径为(718.2±73.6) nm,Zeta电位为(25.5±0.8) mV,对TGF-β1的包封率为(84.82±1.57)%.随着胶原/丝素蛋白复合材料中胶原含量的增加,材料的吸水率、孔隙率逐渐增加,热水溶失率逐渐降低;5种材料对骨髓间充质干细胞(BMSCs)均有促生长和增殖的作用.综合考虑后选用质量比为3∶7和7∶3的胶原/丝素蛋白复合材料分别作为复合支架的致密层和疏松层,构建的胶原/丝素蛋白复合支架为双层结构,一侧结构致密,另一侧疏松多孔.体外释放动力学研究表明,复合支架对TGF-β1具有定向时空控制性释放作用.结论 载TGF-β1纳米粒的双层胶原/丝素蛋白复合支架对TGF-β1具有良好的时空控制释放作用,有望作为生长因子的控缓释支架材料应用于软骨组织工程.%Objective To construct a double layered collagen/silk fibroin composite scaffold incorporating transforming growth factor-β1 (TGF-β1) nanoparticles.Methods The chitosan-heparin (Ch-Hep) nanoparticles incorporating TGF-β1 were prepared and the morphology,particle size,Zeta potential and encapsulation efficiency of the nanoparticles were observed and detected.Five kinds of collagen/silk fibroin composites that had different mass ratio of collagen to silk fibroin (2∶8,3∶7,7∶3,8∶2,10∶0) were prepared,and water

  6. Biofabrication of cell-loaded 3D spider silk constructs.

    Science.gov (United States)

    Schacht, Kristin; Jüngst, Tomasz; Schweinlin, Matthias; Ewald, Andrea; Groll, Jürgen; Scheibel, Thomas

    2015-02-23

    Biofabrication is an emerging and rapidly expanding field of research in which additive manufacturing techniques in combination with cell printing are exploited to generate hierarchical tissue-like structures. Materials that combine printability with cytocompatibility, so called bioinks, are currently the biggest bottleneck. Since recombinant spider silk proteins are non-immunogenic, cytocompatible, and exhibit physical crosslinking, their potential as a new bioink system was evaluated. Cell-loaded spider silk constructs can be printed by robotic dispensing without the need for crosslinking additives or thickeners for mechanical stabilization. Cells are able to adhere and proliferate with good viability over at least one week in such spider silk scaffolds. Introduction of a cell-binding motif to the spider silk protein further enables fine-tuned control over cell-material interactions. Spider silk hydrogels are thus a highly attractive novel bioink for biofabrication. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. 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.

    Science.gov (United States)

    Sinlapabodin, Salita; Amornsudthiwat, Phakdee; Damrongsakkul, Siriporn; Kanokpanont, Sorada

    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 10mm 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(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.

  8. Effect of silk fibroin/hydroxyapatite scaffold on the viability and osteogenic properties of adipose-derived stem cells under osteogenic induction%丝素蛋白/羟基磷灰石支架对成骨诱导脂肪干细胞活性及成骨性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘浩; 褚亚伟; 丁涛; 程力; 朱浩明

    2015-01-01

    BACKGROUND:Adipose-derived stem cels under osteogenic induction can be combined with biodegradable silk fibroin/hydroxyapatite scaffold, which is expected to develop a new biocompatible and osteogenic bone fusion material. OBJECTIVE:To study the effect of silk fibroin/hydroxyapatite composite on the viability and osteogenic properties of adipose-derived stem cels after osteogenic induction. METHODS:Adipose-derived stem cels were obtained from rat’s fat tissue, then adherently cultured, proliferated and passaged in vitro. Passage 3 cels were cultured in conditioned medium for osteogenic induction, and then seeded onto silk fibroin/hydroxyapatite scaffold as experimental group. Adipose-derived stem cels cultured on the cover glasses at the same condition acted as control group. The celular morphology, proliferation and differentiation were assessed respectively by means of phase contrast microscope, MTT assay and alkaline phosphatase activity measurement. RESULTS AND CONCLUSION:After osteogenic induction, adipose-derived stem cels could adhere to the scaffold material and proliferate on the surface of silk fibroin/hydroxyapatite scaffold normaly. No significant difference was found in cel proliferation and alkaline phosphatase activity between the experimental and control groups (P > 0.05), suggesting the celular activity and function were not affected by the material. These findings indicate that silk fibroin/hydroxyapatite composite material has good cytocompatibility. Subject headings: Silk; Hydroxyapatites; Stem Cels; Adipose Tissue; Biocompatible Materials; Tissue Engineering.%背景:成骨诱导后的脂肪干细胞与可降解丝素蛋白/羟基磷灰石支架复合,可望研制出一种具有良好生物相容性及成骨性能的新型骨融合材料。目的:探讨丝素蛋白/羟基磷灰石支架对成骨诱导脂肪干细胞增殖活性及成骨性能的影响。方法:获取大鼠脂肪干细胞后体外贴壁培养、扩增,将第3代细

  9. Suzhou Silk Museum

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    THEIR city’s beautiful gardens and exquisite silk are the pride of the people of Suzhou. The Suzhou Silk Museum has combined the two arts and become one of the biggest local attractions for visitors. Silk culture forms an important part of Suzhou’s history. In 1981 Qian Xiaoping, a female

  10. New application of silk protein

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-03-01

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

  11. Silk structure and degradation.

    Science.gov (United States)

    Liu, Bin; Song, Yu-wei; Jin, Li; Wang, Zhi-jian; Pu, De-yong; Lin, Shao-qiang; Zhou, Chan; You, Hua-jian; Ma, Yan; Li, Jin-min; Yang, Li; Sung, K L Paul; Zhang, Yao-guang

    2015-07-01

    To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk.

  12. Glycopolymer functionalization of engineered spider silk protein-based materials for improved cell adhesion.

    Science.gov (United States)

    Hardy, John G; Pfaff, André; Leal-Egaña, Aldo; Müller, Axel H E; Scheibel, Thomas R

    2014-07-01

    Silk protein-based materials are promising biomaterials for application as tissue scaffolds, due to their processability, biocompatibility, and biodegradability. The preparation of films composed of an engineered spider silk protein (eADF4(C16)) and their functionalization with glycopolymers are described. The glycopolymers bind proteins found in the extracellular matrix, providing a biomimetic coating on the films that improves cell adhesion to the surfaces of engineered spider silk films. Such silk-based materials have potential as coatings for degradable implantable devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Scrutinizing the datasets obtained from nanoscale features of spider silk fibres.

    Science.gov (United States)

    Silva, Luciano P; Rech, Elibio L

    2014-01-01

    Spider silk fibres share unprecedented structural and mechanical properties which span from the macroscale to nanoscale and beyond. This is possible due to the molecular features of modular proteins termed spidroins. Thus, the investigation of the organizational scaffolds observed for spidroins in spider silk fibres is of paramount importance for reverse bioengineering. This dataset consists in describing a rational screening procedure to identify the nanoscale features of spider silk fibres. Using atomic force microscopy operated in multiple acquisition modes, we evaluated silk fibres from nine spider species. Here we present the complete results of the analyses and decrypted a number of novel features that could even rank the silk fibres according to desired mechanostructural features. This dataset will allow other researchers to select the most appropriate models for synthetic biology and also lead to better understanding of spider silk fibres extraordinary performance that is comparable to the best manmade materials.

  14. Microfibrillar Structure of Silks

    Science.gov (United States)

    Putthanarat, Sirina; Eby, Ronald K.; Adams, W. W.; Liu, G. F.

    1998-03-01

    We have previously observed the dragline silk of Nephila clavipes and the silk of Bombyx mori exhibit a range of morphological feature including microfibers (S. Putthanarat; R.K. Eby; W.W. Adams; G.F. Liu J.M.S.-Pure Appl. Chem. 1996, A33(7), 899) and a layered structure. In successive layers the microfibers appeared to be oriented at different small angles to the fiber axis. Further work with the Atomic Force Microscope (AFM) on the silk of B. mori has confirmed these observations and shown other features. One of the latter is a series of raised "steps" spaced somewhat regularly along the fiber. Investigation of peeled three-molted B. mori and Antheraea yamamai (Japanese Tussah) and other silks has shown features very similar to all those in the silk of B. mori. AFM images, characterization, and analyses will be shown for all the silks and their features

  15. Investigate the Effect of Thawing Process on the Self-Assembly of Silk Protein for Tissue Applications

    Science.gov (United States)

    Tran, Hien Anh; Huynh, Khon Chan; Vo, Toi Van

    2017-01-01

    Biological self-assembly is a process in which building blocks autonomously organize to form stable supermolecules of higher order and complexity through domination of weak, noncovalent interactions. For silk protein, the effect of high incubating temperature on the induction of secondary structure and self-assembly was well investigated. However, the effect of freezing and thawing on silk solution has not been studied. The present work aimed to investigate a new all-aqueous process to form 3D porous silk fibroin matrices using a freezing-assisted self-assembly method. This study proposes an experimental investigation and optimization of environmental parameters for the self-assembly process such as freezing temperature, thawing process, and concentration of silk solution. The optical images demonstrated the possibility and potential of −80ST48 treatment to initialize the self-assembly of silk fibroin as well as controllably fabricate a porous scaffold. Moreover, the micrograph images illustrate the assembly of silk protein chain in 7 days under the treatment of −80ST48 process. The surface morphology characterization proved that this method could control the pore size of porous scaffolds by control of the concentration of silk solution. The animal test showed the support of silk scaffold for cell adhesion and proliferation, as well as the cell migration process in the 3D implantable scaffold.

  16. Water-insoluble Silk Films with Silk I Structure

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  17. Silk Batik using Cochineal Dye

    Science.gov (United States)

    The history of silk, including sericulture (the production of raw silk, which requires the raising of silkworms on their natural diet, mulberry leaves) and silk manufacturing, is rich and extensive. It encompasses several famous “silk roads” (trade routes), various cultures and technologies, ideas,...

  18. "Carved Silk" Masterpieces

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    "Carved silk" originated during the Five Dynasties (907-960) period and gained great popularity during the Song Dynasty (960-1279). This particular style of weave, which features the same design on both sides, is clearly defined as if engraved with a knife. The distinct quality of the work led to the moniker "Carved Silk." The two most outstanding pieces of carved silk—

  19. Art on Silk Hoops

    Science.gov (United States)

    Padrick, Deborah

    2012-01-01

    Painting on silk has a magic all its own. Versions of painting on silk can be found throughout the world from Japan and Europe to the United States. Themes for the paintings can be most any type of design or imagery. Applying the liquid dyes is exciting, as the vivid liquid colors flow and blend into the fabric. The process captures students'…

  20. Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets.

    Science.gov (United States)

    Gregory, David A; Zhang, Yu; Smith, Patrick J; Zhao, Xiubo; Ebbens, Stephen J

    2016-08-01

    Inkjet-printed enzyme-powered silk-based micro-rockets are able to undergo autonomous motion in a vast variety of fluidic environments including complex media such as human serum. By means of digital inkjet printing it is possible to alter the catalyst distribution simply and generate varying trajectory behavior of these micro-rockets. Made of silk scaffolds containing enzymes these micro-rockets are highly biocompatible and non-biofouling.

  1. The method of purifying bioengineered spider silk determines the silk sphere properties

    Science.gov (United States)

    Jastrzebska, Katarzyna; Felcyn, Edyta; Kozak, Maciej; Szybowicz, Miroslaw; Buchwald, Tomasz; Pietralik, Zuzanna; Jesionowski, Teofil; Mackiewicz, Andrzej; Dams-Kozlowska, Hanna

    2016-01-01

    Bioengineered spider silks are a biomaterial with great potential for applications in biomedicine. They are biocompatible,biodegradable and can self-assemble into films, hydrogels, scaffolds, fibers, capsules and spheres. A novel, tag-free, bioengineered spider silk named MS2(9x) was constructed. It is a 9-mer of the consensus motif derived from MaSp2–the spidroin of Nephila clavipes dragline silk. Thermal and acidic extraction methods were used to purify MS2(9x). Both purification protocols gave a similar quantity and quality of soluble silk; however, they differed in the secondary structure and zeta potential value. Spheres made of these purified variants differed with regard to critical features such as particle size, morphology, zeta potential and drug loading. Independent of the purification method, neither variant of the MS2(9x) spheres was cytotoxic, which confirmed that both methods can be used for biomedical applications. However, this study highlights the impact that the applied purification method has on the further biomaterial properties. PMID:27312998

  2. Development of new smart materials and spinning systems inspired by natural silks and their applications

    Directory of Open Access Journals (Sweden)

    Jie eCheng

    2016-01-01

    Full Text Available Silks produced by spiders and silkworms are charming natural biological materials with highly optimized hierarchical structures and outstanding physicomechanical properties. The superior performance of silks relies on the integration of a unique protein sequence, a distinctive spinning process, and complex hierarchical structures. Silks have been prepared to form a variety of morphologies and are widely used in diverse applications, for example, in the textile industry, as drug delivery vehicles, and as tissue engineering scaffolds. This review presents an overview of the organization of natural silks, in which chemical and physical functions are optimized, as well as a range of new materials inspired by the desire to mimic natural silk structure and synthesis.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-01

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

  4. Processing of recombinant spider silk proteins into tailor-made materials for biomaterials applications.

    Science.gov (United States)

    Schacht, Kristin; Scheibel, Thomas

    2014-10-01

    Spider silk has extraordinary mechanical properties, is biocompatible and biodegradable, and therefore an ideal material for biomedical applications. However, a drawback for any application is the inhomogeneity of spider silk, as seen for other natural materials, as well as the low availability due to the cannibalism of most spiders. Recently, developed recombinant spider silk proteins ensure constant material properties, as well as scalable production, and further the processing into morphologies other than fibres. Biotechnology enables genetic modification, broadening the range of applications, such as implant coatings, scaffolds for tissue engineering, wound dressing devices as well as drug delivery systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Soft as Silk

    Institute of Scientific and Technical Information of China (English)

    INESAPLESKACHEUSKAYA

    2004-01-01

    In AD 300 a Chinese princess smuggled a silkworm out of the country. It was this treasured dowry item that brought the secrets of silk industry to the rest of the world, at least as legend would have it.

  6. The Tao of Silk

    Institute of Scientific and Technical Information of China (English)

    VALERIE; SARTOR

    2007-01-01

    China’s most ancient gift to the world, silk, arrived long before gunpowder, paper and printmaking. This coveted fabric predated Christ and Buddha. Silk startled the world: Lenient ancient Romans banned it as sexy and immoral. Durable, useful and elegant, it is one of the oldest fibers known to man. Production remained a Chinese secret until 550 when two Nestorian monks, risking their lives,

  7. 人脂肪来源干细胞与膀胱脱细胞基质-丝素蛋白双层支架的生物相容性研究%Human Adipose-De rived Stem Cells and its Biocompatibility with Bladder Acellular Matrix Graft-Silk Fibroin Bilayer Scaffold

    Institute of Scientific and Technical Information of China (English)

    赵阳; 吴稼晟; 周哲; 周娟; 张明; 李伟; 王忠; 孙康; 卢慕峻

    2014-01-01

    Objective To observe the growth of human adipose-derived stem cells (hASCs) in bladder acellular matrix graft-silk fibroin (BAMG-SF) bilayer scaffold and to analyze the biological compatibility of BAMG-SF with hASCs. Methods hASCs were isolated from human subcutaneous adipose tissue after collagenase digesting, filtrating and centrifuging, then cultured in the leaching solution of BAMG-SF. The cytotoxicity of scaffold was evaluated by CCK-8 cell viability assay, and the growth curves were also observed. Surface morphology on BAMG-SF was observed by scanning electron microscopy (SEM). The hASCs of passage 3 were seeded onto the BAMG-SF bilayer scaffolds for 1 week, then the BAMG-SF bilayer scaffolds seeded with hASCs were transplanted into nude mouse for 1 week or 2 weeks. The growth of cells in BAMG-SF biomaterials was observed by HE staining. The species origin of these cells in the BAMG-SF scaffolds cultured in vivo was detected by Immunofluorescence. Results hASCs maintained high proliferation rate in the leaching solution of BAMG-SF and the BAMG-SF scaffolds were nontoxic absolutely. According to the growth curves of hASCs cultured in the leaching solution of the BAMG-SF and DMEM, BAMG-SF scaffolds were conducive to the growth of hASCs. The histological study found that hASCs could grow into the space of the BAMG-SF scaffolds after cultured in vitro and in vivo. There were more cells in the scaffolds cultured in vivo than in vitro. Immuno-fluorescence suggested that some of the cells inside the scaffolds were hASCs. Conclusion BAMG-SF bilayer scaffolds are nontoxic and have a good biocompatibility with hASCs, which can be used as a vehicle for hASCs in bladder defect reconstruction.%目的:观察人脂肪来源干细胞(Human adipose derived stem cells,hASCs)在膀胱黏膜下脱细胞基质-丝素蛋白(Bladder acellular matrix graft-silk fibroin,BAMG-SF)双层支架材料中的生长情况,分析其生物相容性。方法取hASCs,置

  8. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits.

    Science.gov (United States)

    Radtke, Christine

    2016-10-20

    Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa) or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration.

  9. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    Science.gov (United States)

    Radtke, Christine

    2016-01-01

    Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa) or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration. PMID:27775616

  10. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    Directory of Open Access Journals (Sweden)

    Christine Radtke

    2016-10-01

    Full Text Available Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration.

  11. Constructing tissue-engineered adipose with the combination of gene-transfected human umbilical cord mesenchymal stem cells and silk fibroin scaffold%基因转染脐带间充质干细胞与丝素蛋白构建组织工程脂肪***☆

    Institute of Scientific and Technical Information of China (English)

    刘毅; 唐军; 李世龙

    2013-01-01

    transferred with recombinant insulin gene lentiviral vector combined with silk fibroin scaffold in the construction of tissue engineering adipose in Wistar rats. METHODS: Human umbilical cord mesenchymal stem cel s were separated and cultured, and then transfected with recombinant insulin gene lentiviral vector (transfected group) by the best multiplicity of infection =10. The nontransfected human umbilical cord mesenchymal stem cel s were regarded as control group. The human umbilical cord mesenchymal stem cel s in the transfected group and the control group were seeded onto the silk fibroin scaffold and implanted into the subcutaneous layer of Wistar rats. At 12 weeks after implantation, the transplants were taken, and then identified with fluorescence in situ hybridization and observed with histomorphology and scanning electron microscopy. RESULTS AND CONCLUSION: Oil red O staining showed the transplants in two groups were positive, suggesting that the transplants were synthesized in adipose tissue, and the number of fat-like cel s in the transfected group was significantly higher than that in the control group (P < 0.01). Hematoxylin-eosin staining showed significant angiogenesis appeared in or around the new formed tissue, the structure of which was similar to natural adipose tissue. Silk fibroin scaffold in the transfected group was degraded significantly, the number of new vessels in the transfected group was more than that in the control group, and inflammatory cel infiltration in the transfected group was significantly less than that in the control group. Scanning electron microscopy results showed that fat-like cel s in the trasnfected group congregated and the structure was similar to that of the normal adipose tissue; the fat-like cel s in the control group scattered in the pore of the scaffold. Insulin gene could obviously promote human umbilical cord mesenchymal stem cel s to differentiate into adipose; human umbilical cord mesenchymal stem cel s transferred

  12. 3D Printing of Hierarchical Silk Fibroin Structures.

    Science.gov (United States)

    Sommer, Marianne R; Schaffner, Manuel; Carnelli, Davide; Studart, André R

    2016-12-21

    Like many other natural materials, silk is hierarchically structured from the amino acid level up to the cocoon or spider web macroscopic structures. Despite being used industrially in a number of applications, hierarchically structured silk fibroin objects with a similar degree of architectural control as in natural structures have not been produced yet due to limitations in fabrication processes. In a combined top-down and bottom-up approach, we exploit the freedom in macroscopic design offered by 3D printing and the template-guided assembly of ink building blocks at the meso- and nanolevel to fabricate hierarchical silk porous materials with unprecedented structural control. Pores with tunable sizes in the range 40-350 μm are generated by adding sacrificial organic microparticles as templates to a silk fibroin-based ink. Commercially available wax particles or monodisperse polycaprolactone made by microfluidics can be used as microparticle templates. Since closed pores are generated after template removal, an ultrasonication treatment can optionally be used to achieve open porosity. Such pore templating particles can be further modified with nanoparticles to create a hierarchical template that results in porous structures with a defined nanotopography on the pore walls. The hierarchically porous silk structures obtained with this processing technique can potentially be utilized in various application fields from structural materials to thermal insulation to tissue engineering scaffolds.

  13. Interactions between Spider Silk and Cells – NIH/3T3 Fibroblasts Seeded on Miniature Weaving Frames

    Science.gov (United States)

    Kuhbier, Joern W.; Allmeling, Christina; Reimers, Kerstin; Hillmer, Anja; Kasper, Cornelia; Menger, Bjoern; Brandes, Gudrun; Guggenheim, Merlin; Vogt, Peter M.

    2010-01-01

    Background Several materials have been used for tissue engineering purposes, since the ideal matrix depends on the desired tissue. Silk biomaterials have come to focus due to their great mechanical properties. As untreated silkworm silk has been found to be quite immunogenic, an alternative could be spider silk. Not only does it own unique mechanical properties, its biocompatibility has been shown already in vivo. In our study, we used native spider dragline silk which is known as the strongest fibre in nature. Methodology/Principal Findings Steel frames were originally designed and manufactured and woven with spider silk, harvesting dragline silk directly out of the animal. After sterilization, scaffolds were seeded with fibroblasts to analyse cell proliferation and adhesion. Analysis of cell morphology and actin filament alignment clearly revealed adherence. Proliferation was measured by cell count as well as determination of relative fluorescence each after 1, 2, 3, and 5 days. Cell counts for native spider silk were also compared with those for trypsin-digested spider silk. Spider silk specimens displayed less proliferation than collagen- and fibronectin-coated cover slips, enzymatic treatment reduced adhesion and proliferation rates tendentially though not significantly. Nevertheless, proliferation could be proven with high significance (pspider silk does not require any modification to its application as a biomaterial that can rival any artificial material in terms of cell growth promoting properties. We could show adhesion mechanics on intracellular level. Additionally, proliferation kinetics were higher than in enzymatically digested controls, indicating that spider silk does not require modification. Recent findings concerning reduction of cell proliferation after exposure could not be met. As biotechnological production of the hierarchical composition of native spider silk fibres is still a challenge, our study has a pioneer role in researching cellular

  14. Interactions between spider silk and cells--NIH/3T3 fibroblasts seeded on miniature weaving frames.

    Directory of Open Access Journals (Sweden)

    Joern W Kuhbier

    Full Text Available BACKGROUND: Several materials have been used for tissue engineering purposes, since the ideal matrix depends on the desired tissue. Silk biomaterials have come to focus due to their great mechanical properties. As untreated silkworm silk has been found to be quite immunogenic, an alternative could be spider silk. Not only does it own unique mechanical properties, its biocompatibility has been shown already in vivo. In our study, we used native spider dragline silk which is known as the strongest fibre in nature. METHODOLOGY/PRINCIPAL FINDINGS: Steel frames were originally designed and manufactured and woven with spider silk, harvesting dragline silk directly out of the animal. After sterilization, scaffolds were seeded with fibroblasts to analyse cell proliferation and adhesion. Analysis of cell morphology and actin filament alignment clearly revealed adherence. Proliferation was measured by cell count as well as determination of relative fluorescence each after 1, 2, 3, and 5 days. Cell counts for native spider silk were also compared with those for trypsin-digested spider silk. Spider silk specimens displayed less proliferation than collagen- and fibronectin-coated cover slips, enzymatic treatment reduced adhesion and proliferation rates tendentially though not significantly. Nevertheless, proliferation could be proven with high significance (p<0.01. CONCLUSION/SIGNIFICANCE: Native spider silk does not require any modification to its application as a biomaterial that can rival any artificial material in terms of cell growth promoting properties. We could show adhesion mechanics on intracellular level. Additionally, proliferation kinetics were higher than in enzymatically digested controls, indicating that spider silk does not require modification. Recent findings concerning reduction of cell proliferation after exposure could not be met. As biotechnological production of the hierarchical composition of native spider silk fibres is still a

  15. Silk Road policy

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, Y. [Mitsui Mineral Development Engineering Co., Tokyo (Japan)

    1999-04-01

    Landlocked Asia is blessed with rich mineral and energy resources and has great potential to supply these resources to Europe and eastern Asia. With globalisation of markets progressing rapidly, central Asia is now in the spotlight for its economic activity, as a route for international trade and as the heartland of the `Modern Silk Road` of the 21st century. The article discusses the mineral resources of central Asia, covering Kazakhstan, Uzbekistan, Turkmenistan, Kyrghystan, Xingjiang, and Mongolia. Energy resources of the region, coal, oil and natural gas, are mentioned. International organizations and industrial companies like Japan are supporting the transformation of these vast largely unexplored areas to market economies. Construction of the New Silk Road has begun, under the UNDP, and improvement of the Silk Road railway is also underway, with Japanese funding. 3 figs.

  16. Toward spinning artificial spider silk.

    Science.gov (United States)

    Rising, Anna; Johansson, Jan

    2015-05-01

    Spider silk is strong and extensible but still biodegradable and well tolerated when implanted, making it the ultimate biomaterial. Shortcomings that arise in replicating spider silk are due to the use of recombinant spider silk proteins (spidroins) that lack native domains, the use of denaturing conditions under purification and spinning and the fact that the understanding of how spiders control silk formation is incomplete. Recent progress has unraveled the molecular mechanisms of the spidroin N- and C-terminal nonrepetitive domains (NTs and CTs) and revealed the pH and ion gradients in spiders' silk glands, clarifying how spidroin solubility is maintained and how silk is formed in a fraction of a second. Protons and CO2, generated by carbonic anhydrase, affect the stability and structures of the NT and CT in different ways. These insights should allow the design of conditions and devices for the spinning of recombinant spidroins into native-like silk.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyunryung [School of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Che, Lihua; Ha, Yoon [Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 120-749 (Korea, Republic of); Ryu, WonHyoung, E-mail: whryu@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2014-07-01

    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

  18. Conferring biological activity to native spider silk: A biofunctionalized protein-based microfiber.

    Science.gov (United States)

    Wu, Hsuan-Chen; Quan, David N; Tsao, Chen-Yu; Liu, Yi; Terrell, Jessica L; Luo, Xiaolong; Yang, Jen-Chang; Payne, Gregory F; Bentley, William E

    2017-01-01

    Spider silk is an extraordinary material with physical properties comparable to the best scaffolding/structural materials, and as a fiber it can be manipulated with ease into a variety of configurations. Our work here demonstrates that natural spider silk fibers can also be used to organize biological components on and in devices through rapid and simple means. Micron scale spider silk fibers (5-10 μm in diameter) were surface modified with a variety of biological entities engineered with pentaglutamine tags via microbial transglutaminase (mTG). Enzymes, enzyme pathways, antibodies, and fluorescent proteins were all assembled onto spider silk fibers using this biomolecular engineering/biofabrication process. Additionally, arrangement of biofunctionalized fiber should in of itself generate a secondary level of biomolecular organization. Toward this end, as proofs of principle, spatially defined arrangement of biofunctionalized spider silk fiber was shown to generate effects specific to silk position in two cases. In one instance, arrangement perpendicular to a flow produced selective head and neck carcinoma cell capture on silk with antibodies complexed to conjugated protein G. In a second scenario, asymmetric bacterial chemotaxis arose from asymmetric conjugation of enzymes to arranged silk. Overall, the biofabrication processes used here were rapid, required no complex chemistries, were biologically benign, and also the resulting engineered silk microfibers were flexible, readily manipulated and functionally active. Deployed here in microfluidic environments, biofunctional spider silk fiber provides a means to convey complex biological functions over a range of scales, further extending its potential as a biomaterial in biotechnological settings. Biotechnol. Bioeng. 2017;114: 83-95. © 2016 Wiley Periodicals, Inc.

  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.

  20. Reactive Inkjet Printing: Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets (Small 30/2016).

    Science.gov (United States)

    Gregory, David A; Zhang, Yu; Smith, Patrick J; Zhao, Xiubo; Ebbens, Stephen J

    2016-08-01

    On page 4048, X. Zhao, S. J. Ebbens, and co-workers demonstrate the ability to fabricate biocompatible silk microrockets via reactive inkjet printing. The microrockets are powered by catalase and undergo bubble propulsion in the presence of hydrogen peroxide. Microrockets are capable of swimming in a large variety of media including biological solutions. Inkjet printing allows digital definition of enzyme distribution within the silk scaffold to control rocket directionality.

  1. Probing the Silk Road

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    As modern transportation de-veloped rapidly, the Silk Roadbegan to fade from view. Buttwo painters, Geng Yukun andZhao Yixiong, have visited it16 times and have covered allroutes over the past 20 years,reaching as far as Japan in theeast and Turkey in the west.

  2. Beijing Silk Flawers

    Institute of Scientific and Technical Information of China (English)

    JENNIFER LIM

    1997-01-01

    ON a drizzly day 26 years ago, Man Kaijun, Xue Yufeng, Xu Wenjing and around 100 other middle school graduates lined up in a courtyard near Huashi Street in southern Beijing. This group became the first brach of workers at the Beijing Silk Flower Factory, then a workshop-like factory.

  3. Spiders and Silk

    Institute of Scientific and Technical Information of China (English)

    熊世民

    2004-01-01

    Spiders are very small, so it is easy to think that they do not make anything strong. However, a scientist at Oxford University in Britain has discovered this is not true. David Knight says that eight-legged spiders create a material called silk that could be as strong as rope.

  4. Optically switchable natural silk

    Energy Technology Data Exchange (ETDEWEB)

    Krasnov, Igor, E-mail: Igor.Krasnov@hzg.de; Müller, Martin, E-mail: Martin.Mueller@hzg.de [Institut für Experimentelle und Angewandte Physik, Universität Kiel, D-24098 Kiel (Germany); Institute of Materials Research, Helmholtz-Zentrum Geesthacht (HZG), D-21502 Geesthacht (Germany); Krekiehn, Nicolai R.; Jung, Ulrich; Magnussen, Olaf M. [Institut für Experimentelle und Angewandte Physik, Universität Kiel, D-24098 Kiel (Germany); Krywka, Christina [Institute of Materials Research, Helmholtz-Zentrum Geesthacht (HZG), D-21502 Geesthacht (Germany); Zillohu, Ahnaf U.; Strunskus, Thomas [Institut für Materialwissenschaft, Universität Kiel, D-24098 Kiel (Germany); Elbahri, Mady [Institute of Materials Research, Helmholtz-Zentrum Geesthacht (HZG), D-21502 Geesthacht (Germany); Institut für Materialwissenschaft, Universität Kiel, D-24098 Kiel (Germany)

    2015-03-02

    An optically active bio-material is created by blending natural silk fibers with photoisomerizable chromophore molecules—azobenzenebromide (AzBr). The material converts the energy of unpolarized light directly into mechanical work with a well-defined direction of action. The feasibility of the idea to produce optically driven microsized actuators on the basis of bio-material (silk) is proven. The switching behavior of the embedded AzBr molecules was studied in terms of UV/Vis spectroscopy. To test the opto-mechanical properties of the modified fibers and the structural changes they undergo upon optically induced switching, single fiber X-ray diffraction with a micron-sized synchrotron radiation beam was combined in situ with optical switching as well as with mechanical testing and monitoring. The crystalline regions of silk are not modified by the presence of the guest molecules, hence occupy only the amorphous part of the fibers. It is shown that chromophore molecules embedded into fibers can be reversibly switched between the trans and cis conformation by illumination with light of defined wavelengths. The host fibers respond to this switching with a variation of the internal stress. The amplitude of the mechanical response is independent of the applied external stress and its characteristic time is shorter than the relaxation time of the usual mechanical response of silk.

  5. Scale-up of water-based spider silk film casting using a film applicator.

    Science.gov (United States)

    Agostini, Elisa; Winter, Gerhard; Engert, Julia

    2017-08-24

    Spider silk proteins for applications in drug delivery have attracted an increased interest during the past years. Some possible future medical applications for this biocompatible and biodegradable material are scaffolds for tissue engineering, implantable drug delivery systems and coatings for implants. Recently, we reported on the preparation of water-based spider silk films for drug delivery applications. In the current study, we describe the development of a manufacturing technique for casting larger spider silk films from aqueous solution employing a film applicator. Films were characterized in terms of morphology, water solubility, protein secondary structure, thermal stability, and mechanical properties. Different post-treatments were evaluated (phosphate ions, ethanol, steam sterilization and water vapor) to increase the content of β-sheets thereby achieving water insolubility of the films. Finally, the mechanical properties of the spider silk films were improved by incorporating 2-pyrrolidone as plasticizer. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 新型丝素蛋白支架复合兔髓核细胞体内初步构建组织工程髓核的研究%Preliminary Construction of Tissue Engineering Nucleus Pulposus Combining Silk Fibroin Porous Scaffold with Rabbit Nucleus Pulposus Cells

    Institute of Scientific and Technical Information of China (English)

    赵家宁; 徐宝山; 曾超; 杨强; 马信龙; 张春秋; 李秀兰; 张扬

    2014-01-01

    目的:探讨新型丝素蛋白多孔支架复合经PKH26标记的兔髓核细胞初步构建组织工程髓核的可行性。方法消化分离兔髓核细胞,培养获取P1代细胞,对P1代髓核细胞行番红O以及Ⅱ型胶原免疫组织化学染色;PKH26标记兔髓核细胞,MTT法检测标记前后髓核细胞增殖情况,将标记后的细胞接种支架,体外培养4 d后,将细胞-支架复合物植入裸鼠皮下,体内培养12周后,进行活体荧光成像技术检测、HE染色、甲苯胺蓝染色、番红O染色和Ⅱ型胶原免疫组化染色。结果 P1代髓核细胞番红O染色阳性,Ⅱ型胶原免疫组织化学染色阳性;标记后细胞荧光强度分布均匀,标记前后髓核细胞光密度(OD)值比较差异无统计学意义(P>0.05);活体成像技术显示裸鼠皮下植入的细胞-支架复合体呈现强烈荧光;HE染色见多孔支架内壁有大量髓核细胞填满并分泌大量细胞外基质;甲苯胺蓝染色、番红O染色及Ⅱ型胶原免疫组化染色均呈阳性,细胞周围大量细胞外基质分泌。结论以新型丝素蛋白多孔支架复合兔髓核细胞经体内培养形成的类髓核样组织,可用于组织工程化髓核的构建。%Objective To investigate the feasibility of construction of tissue engineering nucleus pulposus by com⁃bining the novel silk fibroin porous scaffold with PKH26 labeled rabbit nucleus pulposus cells. Methods Rabbit nucleus pulposus cells were isolated and cultured, then the passage 1 nucleus pulposus cells were stained with safranin O and typeⅡcollagen immunohistochemical staining. The isolated rabbit nucleus pulposus cells were labeled with PKH26. MTT assay was used for examining the proliferation of the nucleus pulposus cells before and after labeling. Labeled cells were inoculat⁃ed in the scaffold, cultured for 4 days and then the cell-scaffold complexes were implanted subcutaneously into nude mice. After 12 weeks of in

  7. Kesi Silk Tangka of Song Dynasty

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Kesi silk tangka is woven using small shuttles in the tapestry method, with raw silk as the warps and boiled-off silk as the wefts. The wefts make knots with the warps only when there is a need to weave patterns.Kesi silk weaving art emerged with the rise of Buddhist culture. It is a variation of the local wool weaving art with the silk weaving art in the hinterland. A Kesi silk tangka

  8. Low-Tech, Pilot Scale Purification of a Recombinant Spider Silk Protein Analog from Tobacco Leaves

    Directory of Open Access Journals (Sweden)

    René Heppner

    2016-10-01

    Full Text Available Spider dragline is used by many members of the Araneae family not only as a proteinogenic safety thread but also for web construction. Spider dragline has been shown to possess high tensile strength in combination with elastic behavior. This high tensile strength can be attributed to the presence of antiparallel β-sheets within the thread; these antiparallel β-sheets are why the protein is classified as a silk. Due to the properties of spider silk and its technical and medical uses, including its use as a suture material and as a scaffold for tissue regeneration, spider dragline is a focus of the biotechnology industry. The production of sufficient amounts of spider silk is challenging, as it is difficult to produce large quantities of fibers because of the cannibalistic behavior of spiders and their large spatial requirements. In recent years, the heterologous expression of genes coding for spider silk analogs in various hosts, including plants such as Nicotiana tabacum, has been established. We developed a simple and scalable method for the purification of a recombinant spider silk protein elastin-like peptide fusion protein (Q-/K-MaSp1-100× ELP after heterologous production in tobacco leaves involving heat and acetone precipitation. Further purification was performed using centrifugal Inverse Transition Cycling (cITC. Up to 400 mg of highly pure spider silk protein derivatives can be isolated from six kilograms of tobacco leaves, which is the highest amount of silk protein derivatives purified from plants thus far.

  9. Low-Tech, Pilot Scale Purification of a Recombinant Spider Silk Protein Analog from Tobacco Leaves.

    Science.gov (United States)

    Heppner, René; Weichert, Nicola; Schierhorn, Angelika; Conrad, Udo; Pietzsch, Markus

    2016-10-09

    Spider dragline is used by many members of the Araneae family not only as a proteinogenic safety thread but also for web construction. Spider dragline has been shown to possess high tensile strength in combination with elastic behavior. This high tensile strength can be attributed to the presence of antiparallel β-sheets within the thread; these antiparallel β-sheets are why the protein is classified as a silk. Due to the properties of spider silk and its technical and medical uses, including its use as a suture material and as a scaffold for tissue regeneration, spider dragline is a focus of the biotechnology industry. The production of sufficient amounts of spider silk is challenging, as it is difficult to produce large quantities of fibers because of the cannibalistic behavior of spiders and their large spatial requirements. In recent years, the heterologous expression of genes coding for spider silk analogs in various hosts, including plants such as Nicotiana tabacum, has been established. We developed a simple and scalable method for the purification of a recombinant spider silk protein elastin-like peptide fusion protein (Q-/K-MaSp1-100× ELP) after heterologous production in tobacco leaves involving heat and acetone precipitation. Further purification was performed using centrifugal Inverse Transition Cycling (cITC). Up to 400 mg of highly pure spider silk protein derivatives can be isolated from six kilograms of tobacco leaves, which is the highest amount of silk protein derivatives purified from plants thus far.

  10. Engineering of fluorescent emission of silk fibroin composite materials by material assembly.

    Science.gov (United States)

    Lin, Naibo; Meng, Zhaohui; Toh, Guoyang William; Zhen, Yang; Diao, Yingying; Xu, Hongyao; Liu, Xiang Yang

    2015-03-01

    This novel materials assembly technology endows the designated materials with additional/enhanced performance by fixing "functional components" into the materials. Such functional components are molecularly recognized and accommodated by the designated materials. In this regard, two-photon fluorescence (TPF) organic molecules and CdTe quantum dots (QDs) are adopted as functional components to functionalize silk fibers and films. TPF organic molecules, such as, 2,7-bis[2-(4-nitrophenyl) ethenyl]-9,9-dibutylfluorene (NM), exhibit TPF emission quenching because of the molecular stacking that leads to aggregation in the solid form. The specific recognition between -NO2 in the annealed fluorescent molecules and the -NH groups in the silk fibroin molecules decouples the aggregated molecules. This gives rise to a significant increase in the TPF quantum yields of the silk fibers. Similarly, as another type of functional components, CdTe quantum dots (QDs) with different sizes were also adopted in the silk functionalization method. Compared to QDs in solution the fluorescence properties of functionalized silk materials display a long stability at room temperature. As the functional materials are well dispersed at high quantum yields in the biocompatible silk a TPF microscope can be used to pursue 3D high-resolution imaging in real time of the TPF-silk scaffold. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Research on possible medical use of silk produced by caddisfly larvae of Hydropsyche angustipennis (Trichoptera, Insecta).

    Science.gov (United States)

    Tszydel, M; Zabłotni, A; Wojciechowska, D; Michalak, M; Krucińska, I; Szustakiewicz, K; Maj, M; Jaruszewska, A; Strzelecki, J

    2015-05-01

    Silk products are used in medicine as biomaterials, and are particularly promising as scaffolds in tissue engineering. To date only silkworm and spider silk medical potential has been evaluated, whereas the possible application of the material spun by caddisflies in wet environment has not been examined. Biomedical application of every natural material requires biocompatibility testing and evaluation of unique microbiological and mechanical properties. This article focuses on silk fibers formed in caddisflies cocoons of Hydropsyche angustipennis (Insecta, Trichoptera) larvae. Preliminary biological evaluation shows that trichopteran silk is not cytotoxic to human cells. Caddisfly silk itself does not possess antiseptic properties and thus sterilization is indispensable for its application in medicine. Among tested methods of sterilization and disinfection only thermal methods (tyndallization and autoclaving) enabled complete eradication of bacteria and gave fully sterile material. Caddisfly silk appeared to be resistant to high temperature. Fully sterile fibers can be stored without a loss of breaking force and tensile strength. Our work shows that trichopteran silk has a significant potential to be used as a biomaterial.

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

    Science.gov (United States)

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

    2013-12-01

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

  13. Spider silk reduces insect herbivory.

    Science.gov (United States)

    Rypstra, Ann L; Buddle, Christopher M

    2013-02-23

    The role of predators in food webs extends beyond their ability to kill and consume prey. Such trait-mediated effects occur when signals of the predator influence the behaviour of other animals. Because all spiders are silk-producing carnivores, we hypothesized that silk alone would signal other arthropods and enhance non-lethal effects of spiders. We quantified the herbivory inflicted by two beetle species on green bean plants (Phaseolus vulgaris) in the presence of silkworm silk and spider silk along with no silk controls. Single leaflets were treated and enclosed with herbivores in the laboratory and field. Another set of leaflets were treated and left to experience natural herbivory in the field. Entire plants in the field were treated with silk and enclosed with herbivores or left exposed to herbivory. In all cases, the lowest levels of herbivory occurred with spider silk treatments and, in general, silkworm silk produced intermediate levels of leaf damage. These results suggest that silk may be a mechanism for the trait-mediated impacts of spiders and that it might contribute to integrated pest management programmes.

  14. Structural characteristics and biological performance of silk fibroin nanofiber containing microalgae Spirulina extract.

    Science.gov (United States)

    Cha, Bum-Gyu; Kwak, Hyo Won; Park, A Reum; Kim, Shin Hwan; Park, Sook-Young; Kim, Hyun-Jeong; Kim, Ick-Soo; Lee, Ki Hoon; Park, Young Hwan

    2014-04-01

    Silk fibroin (SF) nanofiber scaffold containing microalgae Spirulina extract were prepared by electrospinning and the performance and functionality of the scaffold were evaluated. The viscosity and conductivity of the dope solution of Spirulina containing SF were examined for electrospinability and we found that the morphological structure of SF nanofiber is affected by the concentration of Spirulina extract added. The platelet adhesion and coagulation time test confirmed that the Spirulina containing SF nanofiber scaffold had excellent ability to prevent blood clotting or antithrombogenicity that is comparable to heparin. Low cytotoxicity and excellent cell adhesion and proliferation were also observed for Sprulina containing SF nanofiber scaffold by methylthiazolyldiphenyl-tetrazolium bromide assay and confocal fluorescence microscope using fibroblast and human umbilical vein endothelial cells. Based on these results, we believe SF nanofiber scaffold containing Spirulina extract has the potential to be used as tissue engineering scaffold that requires high hemocompatibility. Copyright © 2013 Wiley Periodicals, Inc.

  15. Injectable silk foams for soft tissue regeneration.

    Science.gov (United States)

    Bellas, Evangelia; Lo, Tim J; Fournier, Eric P; Brown, Joseph E; Abbott, Rosalyn D; Gil, Eun S; Marra, Kacey G; Rubin, J Peter; Leisk, Gary G; Kaplan, David L

    2015-02-18

    Soft tissue fillers are needed for restoration of a defect or augmentation of existing tissues. Autografts and lipotransfer have been under study for soft tissue reconstruction but yield inconsistent results, often with considerable resorption of the grafted tissue. A minimally invasive procedure would reduce scarring and recovery time as well as allow the implant and/or grafted tissue to be placed closer to existing vasculature. Here, the feasibility of an injectable silk foam for soft tissue regeneration is demonstrated. Adipose-derived stem cells survive and migrate through the foam over a 10-d period in vitro. The silk foams are also successfully injected into the subcutaneous space in a rat and over a 3-month period integrating with the surrounding native tissue. The injected foams are palpable and soft to the touch through the skin and returning to their original dimensions after pressure is applied and then released. The foams readily absorb lipoaspirate making the foams useful as a scaffold or template for existing soft tissue filler technologies, useful either as a biomaterial alone or in combination with the lipoaspirate.

  16. Fabrication of 3D porous SF/β-TCP hybrid scaffolds for bone tissue reconstruction.

    Science.gov (United States)

    Park, Hyun Jung; Min, Kyung Dan; Lee, Min Chae; Kim, Soo Hyeon; Lee, Ok Joo; Ju, Hyung Woo; Moon, Bo Mi; Lee, Jung Min; Park, Ye Ri; Kim, Dong Wook; Jeong, Ju Yeon; Park, Chan Hum

    2016-07-01

    Bio-ceramic is a biomaterial actively studied in the field of bone tissue engineering. But, only certain ceramic materials can resolve the corrosion problem and possess the biological affinity of conventional metal biomaterials. Therefore, the recent development of composites of hybrid composites and polymers has been widely studied. In this study, we aimed to select the best scaffold of silk fibroin and β-TCP hybrid for bone tissue engineering. We fabricated three groups of scaffold such as SF (silk fibroin scaffold), GS (silk fibroin/small granule size of β-TCP scaffold) and GM (silk fibroin/medium granule size of β-TCP scaffold), and we compared the characteristics of each group. During characterization of the scaffold, we used scanning electron microscopy (SEM) and a Fourier transform infrared spectroscopy (FTIR) for structural analysis. We compared the physiological properties of the scaffold regarding the swelling ratio, water uptake and porosity. To evaluate the mechanical properties, we examined the compressive strength of the scaffold. During in vitro testing, we evaluated cell attachment and cell proliferation (CCK-8). Finally, we confirmed in vivo new bone regeneration from the implanted scaffolds using histological staining and micro-CT. From these evaluations, the fabricated scaffold demonstrated high porosity with good inter-pore connectivity, showed good biocompatibility and high compressive strength and modulus. In particular, the present study indicates that the GM scaffold using β-TCP accelerates new bone regeneration of implanted scaffolds. Accordingly, our scaffold is expected to act a useful application in the field of bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1779-1787, 2016.

  17. 21 CFR 184.1262 - Corn silk and corn silk extract.

    Science.gov (United States)

    2010-04-01

    ... filaments are extracted with dilute ethanol to produce corn silk extract. The extract may be concentrated at... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Corn silk and corn silk extract. 184.1262 Section... SAFE Listing of Specific Substances Affirmed as GRAS § 184.1262 Corn silk and corn silk extract....

  18. Nutritional value of silk powder from irradiated silk waste

    Energy Technology Data Exchange (ETDEWEB)

    Bunjob, Malee; Lakshanasomya, Niphaporn [Department of Medical Sciences, Nonthaburi (Thailand); Meesilpa, Prateep [Department of Agriculture, Bangkok (Thailand); Sudatis, Boonya [Office of Atomic Energy for Peace, Bangkok (Thailand)

    2002-03-01

    Silk waste from Thai reeling factory was developed into purified silk protein. Cleanliness of silk filaments by boiling in water was firstly needed. After air drying, they were irradiated with Gamma ray using Cobalt-60 at doses of 750 and 1,000 kGy, then the irradiated silk filaments were dissolved in calcium chloride-ethanol-water solution. The next steps would be dialysis followed by freezed dried process to obtain irradiated silk powder. Two samples of 750 and 1,000 kGy irradiated silk powder were analyzed for nutritional components compared with non irradiated silk filaments. It was found that, the fat content in two irradiated samples was distinctive lower than the non irradiated one, however the protein content was nearly the same in three samples. In addition the moisture content in two irradiated samples was distinctive higher than the non irradiated one. These results show that irradiation technique is useful for development of valuable silk protein as biomaterial. (author)

  19. Molecular spring: from spider silk to silkworm silk

    CERN Document Server

    Wu, Xiang; Du, Ning; Xu, Gang-Qin; Li, Bao-Wen

    2009-01-01

    In this letter, we adopt a new approach combining theoretical modeling with silk stretching measurements to explore the mystery of the structures between silkworm and spider silks, leading to the differences in mechanical response against stretching. Hereby the typical stress-strain profiles are reproduced by implementing the newly discovered and verified "$\\beta$-sheet splitting" mechanism, which primarily varies the secondary structure of protein macromolecules; our modeling and simulation results show good accordance with the experimental measurements. Hence, it can be concluded that the post-yielding mechanical behaviors of both kinds of silks are resulted from the splitting of crystallines while the high extensibility of spider dragline is attributed to the tiny $\\beta$-sheets solely existed in spider silk fibrils. This research reveals for the first time the structural factors leading to the significant difference between spider and silkworm silks in mechanical response to the stretching force. Addition...

  20. 聚乙烯醇/柞蚕丝素蛋白材料作为肌腱组织工程支架材料的初步研究%PRELIMINARY STUDY ON POLYVINYL ALCOHOL/WILD ANTHERAEA PERNYI SILK FIBROIN AS NANOFIBER SCAFFOLDS FOR TISSUE ENGINEERED TENDON

    Institute of Scientific and Technical Information of China (English)

    吴琳琳; 李敏; 赵晋; 陈登龙; 周志华

    2011-01-01

    Objective To investigate the cellular compatibility of polyvinyl alcohol (PVA)/wild antheraea pernyi silk fibroin (WSF), and to explore the feasibility for tendon tissue engineering scaffold in vitro.Methods The solutions of WSF (11%), PVA (11%), and PVA/WSF (11%) were prepared with 98% formic acid (mass fraction) at a mass ratio of 9: 1.The electrospinning membranes of WSF, PVA, and PVA/WSF were prepared by electrostatic spinning apparatus.The morphologies of scaffolds were evaluated using scanning electronic microscope (SEM).The tendon cells were isolated from tail tendon of 3-dayold Sprague Dawley rats in vitro.The experiment was performed using the 3rd generation cells.The tendon cells (1 × 106/mL)were cocultured with PVA and PVA/WSF electrospinning film, respectively, and MTT test was used to assess the cell adhesion rate 4, 12 hours after coculture.The tendon cells were cultured in PVA and PVA/WSF extraction medium of different concentration (1, 1/2, and 1/4), respectively; and the absorbance (A) values were detected at 1, 3, 5, and 7 days to evaluate the cytotoxicity.The composite of tendon cells and the PVA or PVA/WSF scaffold were observed by HE staining at 7 days and characterized by SEM at 1,3,5, and 7 days.Results The solution of WSF could not be used to electrospin; and the solution of PVA and PVA/WSF could be electrospun.After coculture of tendon and PVA or PVA/WSF electrospinning membranes, the cell adhesion rates were 26.9% ±0.4% and 87.0% ± 1.0%, respectively for 4 hours, showing significant difference (t=100.400, P=0.000); the cell adhesion rates were 35.2% ± 0.6% and 110.0% ± 1.7%, respectively for 12 hours, showing significant difference (t=42.500, P=0.000).The cytotoxicity of PVA/WSF was less significantly than that of PVA (P < 0.05) and significant difference was observed between 1/2 PVA and 1/4 PVA (P < 0.05).HE staining and SEM images showed that the tendon cells could adhere to PVA and PVA/WSF scaffolds, but

  1. Silk Fibroin under Osmotic Stress

    Science.gov (United States)

    Sohn, Sungkyun; Strey, Helmut H.; Gido, Samuel P.

    2003-03-01

    The osmotic stress method was applied to study the thermodynamics of supramolecular self-assembly phenomena in crystallizable segments of Bombyx mori silkworm silk fibroin. Controlling compositions and phases of silk fibroin solution, the method provided a means for the direct investigation of microscopic and thermodynamic details of these intermolecular interactions in aqueous media. It is apparent that as osmotic pressure increases, silk fibroin molecules get pressurized to align together to form a water-soluble crystalline mesophase (Silk-I), and then gradually become anti-parallel b-sheet structure (Silk-II) at higher osmotic pressure. This behavior becomes more sensitive as the salt concentration decreases. A partial ternary phase diagram of Water-Silk fibroin-LiBr was constructed based on the results. This phase diagram can be utilized to help design a new route for wet spinning of re-generated silk fibroin. Precise control of compositions and corresponding crystalline structure of a silk fibroin solution may enable us to simulate the natural Bombyx mori silkworm spinning process.

  2. Production of Synthetic Spider Silk Fibers

    OpenAIRE

    Copeland, Cameron G.

    2016-01-01

    Orb-weaving spiders produce six different types of silks, each with unique mechanical properties. The mechanical properties of many of these silks, in particular the dragline silk, are of interest for various biomedical applications. Spider silk does not elicit an immune response, making it an ideal material for several applications in the medical field. However, spiders cannot be farmed for their silk as they are cannibalistic and territorial. The most reasonable alternative for producing sp...

  3. Recombinant DNA production of spider silk proteins

    Science.gov (United States)

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

    2013-01-01

    Spider dragline silk is considered to be the toughest biopolymer on Earth due to an extraordinary combination of strength and elasticity. Moreover, silks are biocompatible and biodegradable protein-based materials. Recent advances in genetic engineering make it possible to produce recombinant silks in heterologous hosts, opening up opportunities for large-scale production of recombinant silks for various biomedical and material science applications. We review the current strategies to produce recombinant spider silks. PMID:24119078

  4. Decoding the secrets of spider silk

    OpenAIRE

    Lukas Eisoldt; Andrew Smith; Thomas Scheibel

    2011-01-01

    Spider silks have been employed by man for several thousands of years. Spider silks possess extraordinary mechanical properties due to a combination of strength and extensibility that are superior to most man-made fibers. Spider silk fibers are a protein-based material produced in a highly sophisticated hierarchical process under mild conditions. Here, we review the current understanding of spider silk and its assembly process, as well as discuss the application of silk-based materials to the...

  5. Recombinant DNA production of spider silk proteins.

    Science.gov (United States)

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

    2013-11-01

    Spider dragline silk is considered to be the toughest biopolymer on Earth due to an extraordinary combination of strength and elasticity. Moreover, silks are biocompatible and biodegradable protein-based materials. Recent advances in genetic engineering make it possible to produce recombinant silks in heterologous hosts, opening up opportunities for large-scale production of recombinant silks for various biomedical and material science applications. We review the current strategies to produce recombinant spider silks.

  6. Antheraea pernyi Silk Fiber: A Potential Resource for Artificially Biospinning Spider Dragline Silk

    OpenAIRE

    Yaopeng Zhang; Hongxia Yang; Huili Shao; Xuechao Hu

    2010-01-01

    The outstanding properties of spider dragline silk are likely to be determined by a combination of the primary sequences and the secondary structure of the silk proteins. Antheraea pernyi silk has more similar sequences to spider dragline silk than the silk from its domestic counterpart, Bombyx mori. This makes it much potential as a resource for biospinning spider dragline silk. This paper further verified its possibility as the resource from the mechanical properties and the structures of t...

  7. Antheraea pernyi Silk Fiber: A Potential Resource for Artificially Biospinning Spider Dragline Silk

    OpenAIRE

    Yaopeng Zhang; Hongxia Yang; Huili Shao; Xuechao Hu

    2010-01-01

    The outstanding properties of spider dragline silk are likely to be determined by a combination of the primary sequences and the secondary structure of the silk proteins. Antheraea pernyi silk has more similar sequences to spider dragline silk than the silk from its domestic counterpart, Bombyx mori. This makes it much potential as a resource for biospinning spider dragline silk. This paper further verified its possibility as the resource from the mechanical properties and the structures of t...

  8. 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.

  9. BMP-silk composite matrices heal critically sized femoral defects.

    Science.gov (United States)

    Kirker-Head, C; Karageorgiou, V; Hofmann, S; Fajardo, R; Betz, O; Merkle, H P; Hilbe, M; von Rechenberg, B; McCool, J; Abrahamsen, L; Nazarian, A; Cory, E; Curtis, M; Kaplan, D; Meinel, L

    2007-08-01

    Clinical drawbacks of bone grafting prompt the search for alternative bone augmentation technologies such as use of growth and differentiation factors, gene therapy, and cell therapy. Osteopromotive matrices are frequently employed for the local delivery and controlled release of these augmentation agents. Some matrices also provide an osteoconductive scaffold to support new bone growth. In this study, silkworm-derived silk fibroin was evaluated as an osteoconductive matrix for healing critical sized mid-femoral segmental defects in nude rats. Four treatment groups were assessed over eight weeks: silk scaffolds (SS) with recombinant human BMP-2 (rhBMP-2) and human mesenchymal stem cells (HMSC) that had been pre-differentiated along an osteoblastic lineage ex vivo (Group I; pdHMSC/rhBMP-2/SS); SS with rhBMP-2 and undifferentiated HMSCs (Group II; udHMSC/rhBMP-2/SS); SS and rhBMP-2 alone (Group III; rhBMP-2/SS); and empty defects (Group IV). Bi-weekly radiographs revealed a progressive and similar increase in Group I-III mean defect mineralization through post-operative week (POW) 8. Radiographs, dual energy x-ray absorptiometry, and micro-computed tomography confirmed that Groups I-III exhibited similar substantial and significantly (pwoven and lamellar bone bridging islands of silk matrix in Groups I and III. Group II defects possessed comparatively less new bone which was most abundant adjacent to the parent bone margins. Elsewhere the silk matrix was more often enveloped by poorly differentiated loose fibrous connective tissue. Group IV defects showed minimal new bone formation. None of the treatment groups attained the mean mineralization or the mean biomechanical strength of identical defects implanted with SS and pdHMSCs alone in a previous study. However, addition of rhBMP-2 to SS prompted more bone than was previously generated using udHMSC/SS or SS alone. These data imply the clinical potential of silk scaffolds and rhBMP-2 as composite osteopromotive

  10. Artificial Polymeric Scaffolds as Extracellular Matrix Substitutes for Autologous Conjunctival Goblet Cell Expansion

    Science.gov (United States)

    He, Min; Storr-Paulsen, Thomas; Wang, Annie L.; Ghezzi, Chiara E.; Wang, Siran; Fullana, Matthew; Karamichos, Dimitrios; Utheim, Tor P.; Islam, Rakibul; Griffith, May; Islam, M. Mirazul; Hodges, Robin R.; Wnek, Gary E.; Kaplan, David L.; Dartt, Darlene A.

    2016-01-01

    Purpose We fabricated and investigated polymeric scaffolds that can substitute for the conjunctival extracellular matrix to provide a substrate for autologous expansion of human conjunctival goblet cells in culture. Methods We fabricated two hydrogels and two silk films: (1) recombinant human collagen (RHC) hydrogel, (2) recombinant human collagen 2-methacryloylxyethyl phosphorylcholine (RHC-MPC) hydrogel, (3) arginine-glycine-aspartic acid (RGD) modified silk, and (4) poly-D-lysine (PDL) coated silk, and four electrospun scaffolds: (1) collagen, (2) poly(acrylic acid) (PAA), (3) poly(caprolactone) (PCL), and (4) poly(vinyl alcohol) (PVA). Coverslips and polyethylene terephthalate (PET) were used for comparison. Human conjunctival explants were cultured on scaffolds for 9 to 15 days. Cell viability, outgrowth area, and the percentage of cells expressing markers for stratified squamous epithelial cells (cytokeratin 4) and goblet cells (cytokeratin 7) were determined. Results Most of cells grown on all scaffolds were viable except for PCL in which only 3.6 ± 2.2% of the cells were viable. No cells attached to PVA scaffold. The outgrowth was greatest on PDL-silk and PET. Outgrowth was smallest on PCL. All cells were CK7-positive on RHC-MPC while 84.7 ± 6.9% of cells expressed CK7 on PDL-silk. For PCL, 87.10 ± 3.17% of cells were CK7-positive compared to PET where 67.10 ± 12.08% of cells were CK7-positive cells. Conclusions Biopolymer substrates in the form of hydrogels and silk films provided for better adherence, proliferation, and differentiation than the electrospun scaffolds and could be used for conjunctival goblet cell expansion for eventual transplantation once undifferentiated and stratified squamous cells are included. Useful polymer scaffold design characteristics have emerged from this study. PMID:27832279

  11. Exploiting spiders’ silk

    Directory of Open Access Journals (Sweden)

    Paula Gould

    2002-12-01

    As today’s film-goers and readers of the original Spiderman comic strip will know, spider silk makes an ideal tool for a modern day super-hero. The fine line can be produced at will, holds our hero’s weight as he swings between tall buildings, and then clumps together to trap dastardly villains in a tangled, sticky mess. Highly useful if your daily job description includes rescuing distressed damsels from improbable locations and preventing a thoroughly nasty goblin from wreaking havoc on your home city.

  12. Structure to function: Spider silk and human collagen

    Science.gov (United States)

    Rabotyagova, Olena S.

    , morphological features and assembly. Aside from fundamental perspectives, we anticipate that these results will provide a blueprint for the design of precise materials for a range of potential applications such as controlled release devices, functional coatings, components of tissue regeneration materials and environmentally friendly polymers in future studies. In the second part of this work, human collagen type I was studied as another representative of the family of fibrous proteins. Collagen type I is the most abundant extracellular matrix protein in the human body, providing the basis for tissue structure and directing cellular functions. Collagen has a complex structural hierarchy, organized at different length scales, including the characteristic triple helical feature. In the present study we assessed the relationship between collagen structure (native vs. denatured) and sensitivity to UV radiation with a focus on changes in the primary structure, conformation, microstructure and material properties. Free radical reactions are involved in collagen degradation and a mechanism for UV-induced collagen degradation related to structure was proposed. The results from this study demonstrated the role of collagen supramolecular organization (triple helix) in the context of the effects of electromagnetic radiation on extracellular matrices. Owing to the fact that both silks and collagens are proteins that have found widespread interest for biomaterial related needs, we anticipate that the current studies will serve as a foundation for future biomaterial designs with controlled properties. Furthermore, fundamental insight into self-assembly and environmentally-2mediated degradation, will build a foundation for fundamental understanding of the remodeling and functions of these types of fibrous proteins in vivo and in vitro. This type of insight is essential for many areas of scientific inquiry, from drug delivery, to scaffolds for tissue engineering, and to the stability of

  13. 取向性丝素蛋白支架复合脂肪干细胞体外构建组织工程软骨%In vitro cartilage tissue engineering using oriented silk fibroin scaffold and adipose-derived stem cells

    Institute of Scientific and Technical Information of China (English)

    杨强; 丁晓明; 徐宝山; 赵艳红; 刘越; 张杨; 胡永成; 马信龙

    2015-01-01

    目的 探讨丝素蛋白支架复合脂肪干细胞体外构建组织工程软骨的可行性.方法 以丝素蛋白为原料制作具有仿生取向微孔结构的支架,接种第3代兔脂肪干细胞,加入成软骨诱导液进行培养.CCK-8检测诱导液对细胞增殖的影响,组织学及Ⅱ型胶原免疫组化染色观察脂肪干细胞的基质分泌,Elisa定量检测蛋白多糖和Ⅱ型胶原分泌量,实时定量PCR检测软骨特定基因Ⅱ型胶原、蛋白多糖和Sox-9的表达水平,并检测支架的力学性能.结果 扫描电镜下支架纵切面为平行排列的微管样结构,横切面为椭圆或圆形孔隙结构.脂肪干细胞在支架上黏附良好,随诱导时间延长分泌大量取向分布的细胞外基质.脂肪干细胞在支架上呈对数生长趋势,成软骨诱导组吸光度值在诱导第7天、第21天高于普通培养基组.组织学及免疫组化染色结果在诱导第21天均呈阳性.诱导第21天蛋白多糖含量[(15.89±1.64) μg/mg]和Ⅱ型胶原含量[(1.89±0.28) μg/mg]高于诱导第7天[(5.02±0.91) μg/mg和(0.28±0.08) μg/mg],第7天高于第0天[(0.77±0.25) μg/mg和(0.12±0.05) μg/mg)].Ⅱ型胶原、蛋白聚糖、Sox-9的基因表达水平在第21天均高于第0天和第7天.第21天支架纵向压缩弹性模量为(84.41±7.12) kPa,高于第0天的(52.48±5.78) kPa和第7天的(59.30±6.43) kPa.结论 取向性丝素蛋白支架接种成软骨诱导的脂肪干细胞能够在体外构建组织工程软骨,并能提高支架的力学强度.%Objective To investigate the feasibility of fabricating an oriented scaffold combined with chondrogenic-induced adipose-derived stem cells (ADSCs) for cartilage tissue engineering in vitro.Methods The silk fibroin scaffold with biomimetic oriented microstructure was made by the directional crystallization technology.The structure of scaffold was observed by the SEM.Rabbit ADSCs of passage 3 were seeded into the scaffold,and induced by chondrogenic medium

  14. Cell culture's spider silk road.

    Science.gov (United States)

    Perkel, Jeffrey

    2014-06-01

    A number of synthetic and natural materials have been tried in cell culture and tissue engineering applications in recent years. Now Jeffrey Perkel takes a look at one new culture component that might surprise you-spider silk.

  15. A new route for silk

    Science.gov (United States)

    Omenetto, Fiorenzo G.; Kaplan, David L.

    2008-11-01

    Famous for its use in clothing since early times, silk is now finding a new application as a useful biocompatible material in photonic devices. Thin films, diffraction gratings and organic photonic crystals are just a few of the exciting possibilities.

  16. Effects of Combinates Transplantation of Bone Marrow Mesenchymal Stem Cells with Silk Fibroin Porous Scaffolds on Repair of Acute Hemi-transection Spinal Cord Injury in Rats%移植BMMSCs-蚕丝蛋白生物支架对急性大鼠脊髓半切损伤修复的影响

    Institute of Scientific and Technical Information of China (English)

    屈涛; 王世勇; 张军华; 文益民

    2013-01-01

    Objective:To investigate the effects of transplantation of BMMSCs-SFPS on repairing acute hemi-transection SCI in rats.Methods:BMMSCs were harvested by density gradient centrifugation and adherent-cultured.The third generation BMMSCs in logarithmic growth phase were injected into SFPS to construct the BMMSCs-SFPS scaffolds,which biocompatibility was observed in vitro at 2 weeks,40 SD adult rats were subjected hemi-transect at T11 level to build SCI model then divided randomly into 4 groups (each group,n=10),BMMSCs-SFPS,BMMSCs and SFPS that were implanted in group A,B,and C,respectively.Group D was blank control group.At 1,2,3 and 4 weeks after surgery,the functional recovery of the hind limbs was evaluated by the Basso-Beattie-Bresnahan (BBB) locomotors rating score,And HE staining and immun-fluorescence assay were adopted at one month after surgery.Results:Abundance BMMSC has been confirmed adhering to the internal surface of scaffolds by SEM after co-cultivated 14 days,cells attached well to each other.After the surgery of hemi-transection 1 month,HE staining showed that the cavity of spinal marrow in group A was smaller than that in group B,C and D.Immunofluorescence staining showed that more neurofilament 200 (NF-200) positive fibers and Nestin positive cells were detected in group A,but GFAP positive cells significantly less than that in other three groups.The BBB scores at 2,3 and 4 weeks after surgery in group A was Top Rating than those in other 3 groups,and group D was the lowest at each test time,and the differences between groups were statistically significant (P <0.01).Conclusions:SFPS which can be biocompatible with BMMSCs in vitro,BMMSCs-SFPS scaffolds can ensure the number of survivalling BMMSCs and inhibit glial scar after transplanted into spinal cord,Synergistic effect of co-transplant BMMSCs-SFPS scaffolds can promote SCI rat motor function recover.%目的:以蚕丝蛋白支架(silk fibroin porous scaffolds SFPS)

  17. Biocompatible silk-conducting polymer composite trilayer actuators

    Science.gov (United States)

    Fengel, Carly V.; Bradshaw, Nathan P.; Severt, Sean Y.; Murphy, Amanda R.; Leger, Janelle M.

    2017-05-01

    Biocompatible materials capable of controlled actuation are in high demand for use in biomedical applications such as dynamic tissue scaffolding, valves, and steerable surgical tools. Conducting polymer actuators are of interest because they operate in aqueous electrolytes at low voltages and can generate stresses similar to natural muscle. Recently, our group has demonstrated a composite material of silk and poly(pyrrole) (PPy) that is mechanically robust, made from biocompatible materials, and bends under an applied voltage when incorporated into a simple bilayer device architecture and actuated using a biologically relevant electrolyte. Here we present trilayer devices composed of two silk-PPy composite layers separated by an insulating silk layer. The trilayer architecture allows one side to expand while the other contracts, resulting in improved performance over bilayer devices. Specifically, this configuration shows a larger angle of deflection per volt applied than the analogous bilayer system, while maintaining a consistent current response throughout cycling. In addition, the overall motion of the trilayer devices is more symmetric than that of the bilayer analogs, allowing for fully reversible operation.

  18. Optically probing torsional superelasticity in spider silks

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-11

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

  19. Optically probing torsional superelasticity in spider silks

    Science.gov (United States)

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

    2013-11-01

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 102-3 rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices.

  20. Production of Silk & Wool Blended Worsted Cloth

    Institute of Scientific and Technical Information of China (English)

    段亚峰; 许琳

    2004-01-01

    Wool & silk blended fancy suiting is desinged. Through trial-production with silk sliver and Australian wool top, the spinning technology is investigated, and the relationship of spinning technology, blending ratio and yam construction is discussed.

  1. Phase behavior and hydration of silk fibroin.

    Science.gov (United States)

    Sohn, Sungkyun; Strey, Helmut H; Gido, Samuel P

    2004-01-01

    The osmotic stress method was applied to study the thermodynamics of supramolecular self-assembly phenomena in crystallizable segments of Bombyx mori silkworm silk fibroin. By controlling compositions and phases of silk fibroin solution, the method provided a means for the direct investigation of microscopic and thermodynamic details of these intermolecular interactions in aqueous media. It is apparent that as osmotic pressure increases, silk fibroin molecules are crowded together to form silk I structure and then with further increase in osmotic pressure become an antiparallel beta-sheet structure, silk II. A partial ternary phase diagram of water-silk fibroin-LiBr was constructed based on the results. The results provide quantitative evidence that the silk I structure must contain water of hydration. The enhanced control over structure and phase behavior using osmotic stress, as embodied in the phase diagram, could potentially be utilized to design a new route for water-based wet spinning of regenerated silk fibroin.

  2. Reproducing natural spider silks' copolymer behavior in synthetic silk mimics.

    Science.gov (United States)

    An, Bo; Jenkins, Janelle E; Sampath, Sujatha; Holland, Gregory P; Hinman, Mike; Yarger, Jeffery L; Lewis, Randolph

    2012-12-10

    Dragline silk from orb-weaving spiders is a copolymer of two large proteins, major ampullate spidroin 1 (MaSp1) and 2 (MaSp2). The ratio of these proteins is known to have a large variation across different species of orb-weaving spiders. NMR results from gland material of two different species of spiders, N. clavipes and A. aurantia , indicates that MaSp1 proteins are more easily formed into β-sheet nanostructures, while MaSp2 proteins form random coil and helical structures. To test if this behavior of natural silk proteins could be reproduced by recombinantly produced spider silk mimic protein, recombinant MaSp1/MaSp2 mixed fibers as well as chimeric silk fibers from MaSp1 and MaSp2 sequences in a single protein were produced based on the variable ratio and conserved motifs of MaSp1 and MaSp2 in native silk fiber. Mechanical properties, solid-state NMR, and XRD results of tested synthetic fibers indicate the differing roles of MaSp1 and MaSp2 in the fiber and verify the importance of postspin stretching treatment in helping the fiber to form the proper spatial structure.

  3. Braiding Parameters of Medical Silk Braided Suture

    Institute of Scientific and Technical Information of China (English)

    张佩华; 吴建华

    2001-01-01

    The relationships between braiding parameters and properties of medical silk braided suture are investigated. Experimental results indicate that the main factors affecting the suture properties include the proportion of core silk and shell silk, braiding density and braiding tension. The results show that the braiding technology significantly influences the suture properties and the optimal braiding parameters were obtained by using the regression method.

  4. Semiotic scaffolding

    DEFF Research Database (Denmark)

    Hoffmeyer, Jesper

    2015-01-01

    Life processes at all levels (from the genetic to the behavioral) are coordinated by semiotic interactions between cells, tissues, membranes, organs, or individuals and tuned through evolution to stabilize important functions. A stabilizing dynamics based on a system of semiotic scaffoldings...... implies that genes do not control the life of organisms, they merely scaffold it. The nature-nurture dynamics is thus far more complex and open than is often claimed. Contrary to physically based interactions, semiotic interactions do not depend on any direct causal connection between the sign vehicle...... semiotic scaffolding is not, of course, exclusive for phylogenetic and ontogenetic development, it is also an important dynamical element in cultural evolution....

  5. In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction.

    Directory of Open Access Journals (Sweden)

    Anne Steins

    Full Text Available Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial with outstanding mechanical properties and a slow degradation rate, as a potential scaffold for bladder reconstruction by studying the cellular response of primary bladder cells to this biomaterial. We demonstrate that spider silk without any additional biological coating supports adhesion and growth of primary human urothelial cells (HUCs, which are multipotent bladder cells able to differentiate into the various epithelial layers of the bladder. HUCs cultured on spider silk did not show significant changes in the expression of various epithelial-to-mesenchymal transition and fibrosis associated genes, and demonstrated only slight reduction in the expression of adhesion and cellular differentiation genes. Furthermore, flow cytometric analysis showed that most of the silk-exposed HUCs maintain an undifferentiated immunophenotype. These results demonstrate that spider silk from the Nephila edulis spider supports adhesion, survival and growth of HUCs without significantly altering their cellular properties making this type of material a suitable candidate for being tested in pre-clinical models for bladder reconstruction.

  6. In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction.

    Science.gov (United States)

    Steins, Anne; Dik, Pieter; Müller, Wally H; Vervoort, Stephin J; Reimers, Kerstin; Kuhbier, Jörn W; Vogt, Peter M; van Apeldoorn, Aart A; Coffer, Paul J; Schepers, Koen

    2015-01-01

    Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial with outstanding mechanical properties and a slow degradation rate, as a potential scaffold for bladder reconstruction by studying the cellular response of primary bladder cells to this biomaterial. We demonstrate that spider silk without any additional biological coating supports adhesion and growth of primary human urothelial cells (HUCs), which are multipotent bladder cells able to differentiate into the various epithelial layers of the bladder. HUCs cultured on spider silk did not show significant changes in the expression of various epithelial-to-mesenchymal transition and fibrosis associated genes, and demonstrated only slight reduction in the expression of adhesion and cellular differentiation genes. Furthermore, flow cytometric analysis showed that most of the silk-exposed HUCs maintain an undifferentiated immunophenotype. These results demonstrate that spider silk from the Nephila edulis spider supports adhesion, survival and growth of HUCs without significantly altering their cellular properties making this type of material a suitable candidate for being tested in pre-clinical models for bladder reconstruction.

  7. Covalent Immobilization of Catalase onto Regenerated Silk Fibroins via Tyrosinase-Catalyzed Cross-Linking.

    Science.gov (United States)

    Wang, Ping; Qi, Chenglong; Yu, Yuanyuan; Yuan, Jiugang; Cui, Li; Tang, Gengtie; Wang, Qiang; Fan, Xuerong

    2015-09-01

    Regenerated silk fibroins could be used as medical scaffolds and carrier materials for enzyme immobilization. In the present work, tyrosinase enzyme was used for enzymatic oxidation of silk fibroins, followed by immobilization of catalase onto the fibroin surfaces through physical adsorption and covalent cross-linking as well. Spectrophotometry, SDS-PAGE, and Fourier transform infrared spectroscopy (FTIR) were used to examine the efficiency of enzymatic oxidation and catalase immobilization, respectively. The results indicate that tyrosine residues in silk fibroins could be oxidized and converted to the active o-quinones. Incubating silk fibroins with catalase and tyrosinase led to a noticeable change of molecular weight distribution, indicating the occurrence of the cross-links between silk fibroins and catalase molecules. Two different pathways were proposed for the catalase immobilizations, and the method based on grafting of catalase onto the freeze-dried fibroin membrane is more acceptable. The residual enzyme activity for the immobilized catalase exhibited higher than that of the control after repeated washing cycles. Meanwhile, the thermal stability and alkali resistance were also slightly improved as compared to free catalase. The mechanisms of enzymatic immobilization are also concerned.

  8. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres.

    Science.gov (United States)

    Liang, Bo; Fang, Lu; Hu, Yichuan; Yang, Guang; Zhu, Qin; Ye, Xuesong

    2014-04-21

    A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m(-1). During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □(-1) with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H₂O₂ electrode with a sensitivity of 0.56 mA mM(-1) cm(-2), a linear range of 0-2.5 mM and an ultralow detection limit of 0.2 μM (S/N = 3). A glucose biosensor electrode was further fabricated by enzyme immobilization. The results show a sensitivity of 150.8 μA mM(-1) cm(-2) and a low detection limit of 1 μM (S/N = 3) for glucose detection. The strategy of coating graphene sheets on a silk fibre surface provides a new approach for developing electrically conductive biomaterials, tissue engineering scaffolds, bendable electrodes, and wearable biomedical devices.

  9. Electrospinning of silk fibroin from all aqueous solution at low concentration.

    Science.gov (United States)

    Kishimoto, Yuki; Morikawa, Hideaki; Yamanaka, Shigeru; Tamada, Yasushi

    2017-04-01

    Non-woven mats of Bombyx mori silk fibroin were fabricated using electrospinning with an all aqueous solution at electrospinning at low concentrations of 5wt%. Evaluation of structural and mechanical properties of the non-woven mat fabricated with water solvent revealed that it is safe for use in the human body. It is anticipated for wider use in medical materials such as cellular scaffolds for tissue engineering.

  10. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    Science.gov (United States)

    Meirovitch, Sigal; Shtein, Zvi; Ben-Shalom, Tal; Lapidot, Shaul; Tamburu, Carmen; Hu, Xiao; Kluge, Jonathan A.; Raviv, Uri; Kaplan, David L.; Shoseyov, Oded

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites. PMID:27649169

  11. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly.

    Science.gov (United States)

    Meirovitch, Sigal; Shtein, Zvi; Ben-Shalom, Tal; Lapidot, Shaul; Tamburu, Carmen; Hu, Xiao; Kluge, Jonathan A; Raviv, Uri; Kaplan, David L; Shoseyov, Oded

    2016-09-18

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites.

  12. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    Directory of Open Access Journals (Sweden)

    Sigal Meirovitch

    2016-09-01

    Full Text Available The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs and recombinant spider silk protein fused to a cellulose binding domain (CBD is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS, small angle X-ray scattering (SAXS and cryo-transmission electron microscopy (TEM indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites.

  13. Evaluation of silk biomaterials in combination with extracellular matrix coatings for bladder tissue engineering with primary and pluripotent cells.

    Directory of Open Access Journals (Sweden)

    Debra Franck

    Full Text Available Silk-based biomaterials in combination with extracellular matrix (ECM coatings were assessed as templates for cell-seeded bladder tissue engineering approaches. Two structurally diverse groups of silk scaffolds were produced by a gel spinning process and consisted of either smooth, compact multi-laminates (Group 1 or rough, porous lamellar-like sheets (Group 2. Scaffolds alone or coated with collagen types I or IV or fibronectin were assessed independently for their ability to support attachment, proliferation, and differentiation of primary cell lines including human bladder smooth muscle cells (SMC and urothelial cells as well as pluripotent cell populations, such as murine embryonic stem cells (ESC and induced pluripotent stem (iPS cells. AlamarBlue evaluations revealed that fibronectin-coated Group 2 scaffolds promoted the highest degree of primary SMC and urothelial cell attachment in comparison to uncoated Group 2 controls and all Group 1 scaffold variants. Real time RT-PCR and immunohistochemical (IHC analyses demonstrated that both fibronectin-coated silk groups were permissive for SMC contractile differentiation as determined by significant upregulation of α-actin and SM22α mRNA and protein expression levels following TGFβ1 stimulation. Prominent expression of epithelial differentiation markers, cytokeratins, was observed in urothelial cells cultured on both control and fibronectin-coated groups following IHC analysis. Evaluation of silk matrices for ESC and iPS cell attachment by alamarBlue showed that fibronectin-coated Group 2 scaffolds promoted the highest levels in comparison to all other scaffold formulations. In addition, real time RT-PCR and IHC analyses showed that fibronectin-coated Group 2 scaffolds facilitated ESC and iPS cell differentiation toward both urothelial and smooth muscle lineages in response to all trans retinoic acid as assessed by induction of uroplakin and contractile gene and protein expression. These

  14. Decoding the secrets of spider silk

    Directory of Open Access Journals (Sweden)

    Lukas Eisoldt

    2011-03-01

    Full Text Available Spider silks have been employed by man for several thousands of years. Spider silks possess extraordinary mechanical properties due to a combination of strength and extensibility that are superior to most man-made fibers. Spider silk fibers are a protein-based material produced in a highly sophisticated hierarchical process under mild conditions. Here, we review the current understanding of spider silk and its assembly process, as well as discuss the application of silk-based materials to the fields of biomedicine and materials engineering.

  15. Proteomic Evidence for Components of Spider Silk Synthesis from Black Widow Silk Glands and Fibers.

    Science.gov (United States)

    Chaw, Ro Crystal; Correa-Garhwal, Sandra M; Clarke, Thomas H; Ayoub, Nadia A; Hayashi, Cheryl Y

    2015-10-02

    Spider silk research has largely focused on spidroins, proteins that are the primary components of spider silk fibers. Although a number of spidroins have been characterized, other types of proteins associated with silk synthesis are virtually unknown. Previous analyses of tissue-specific RNA-seq libraries identified 647 predicted genes that were differentially expressed in silk glands of the Western black widow, Latrodectus hesperus. Only ∼5% of these silk-gland specific transcripts (SSTs) encode spidroins; although the remaining predicted genes presumably encode other proteins associated with silk production, this is mostly unverified. Here, we used proteomic analysis of multiple silk glands and dragline silk fiber to investigate the translation of the differentially expressed genes. We find 48 proteins encoded by the differentially expressed transcripts in L. hesperus major ampullate, minor ampullate, and tubuliform silk glands and detect 17 SST encoded proteins in major ampullate silk fibers. The observed proteins include known silk-related proteins, but most are uncharacterized, with no annotation. These unannotated proteins likely include novel silk-associated proteins. Major and minor ampullate glands have the highest overlap of identified proteins, consistent with their shared, distinctive ampullate shape and the overlapping functions of major and minor ampullate silks. Our study substantiates and prioritizes predictions from differential expression analysis of spider silk gland transcriptomes.

  16. Tissue regeneration in vivo within recombinant spidroin 1 scaffolds.

    Science.gov (United States)

    Moisenovich, Mikhail M; Pustovalova, Olga; Shackelford, Julia; Vasiljeva, Tamara V; Druzhinina, Tatiana V; Kamenchuk, Yana A; Guzeev, Vitaly V; Sokolova, Olga S; Bogush, Vladimir G; Debabov, Vladimir G; Kirpichnikov, Mikhail P; Agapov, Igor I

    2012-05-01

    One of the major tasks of tissue engineering is to produce tissue grafts for the replacement or regeneration of damaged tissue, and natural and recombinant silk-based polymer scaffolds are promising candidates for such grafts. Here, we compared two porous scaffolds made from different silk proteins, fibroin of Bombyx mori and a recombinant analog of Nephila clavipes spidroin 1 known as rS1/9, and their biocompatibility and degradation behavior in vitro and in vivo. The vascularization and intergrowth of the connective tissue, which was penetrated with nerve fibers, at 8 weeks after subcutaneous implantation in Balb/c mice was more profound using the rS1/9 scaffolds. Implantation of both scaffolds into bone defects in Wistar rats accelerated repair compared to controls with no implanted scaffold at 4 weeks. Based on the number of macrophages and multinuclear giant cells in the subcutaneous area and the number of osteoclasts in the bone, regeneration was determined to be more effective after the rS1/9 scaffolds were implanted. Microscopic examination of the morphology of the matrices revealed differences in their internal microstructures. In contrast to fibroin-based scaffolds, the walls of the rS1/9 scaffolds were visibly thicker and contained specific micropores. We suggest that the porous inner structure of the rS1/9 scaffolds provided a better micro-environment for the regenerating tissue, which makes the matrices derived from the recombinant rS1/9 protein favorable candidates for future in vivo applications.

  17. Brocade SilkWorm 3250

    Institute of Scientific and Technical Information of China (English)

    张越

    2004-01-01

    Brocade SilkWorm 3250是一款8端口的入门级光纤交换机产品。它采用1U设计,主要被设计用来简化SAN存储系统的部署和监控管理。作为基于Brocade第三代通信技术的产品之一.SilkWorm 3250能够提供2Gbps的光纤通道吞吐量.可大幅度改善交换机的运行状况。

  18. Scaffolded biology.

    Science.gov (United States)

    Minelli, Alessandro

    2016-09-01

    Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology.

  19. Into the groove: instructive silk-polypyrrole films with topographical guidance cues direct DRG neurite outgrowth.

    Science.gov (United States)

    Hardy, John G; Khaing, Zin Z; Xin, Shangjing; Tien, Lee W; Ghezzi, Chiara E; Mouser, David J; Sukhavasi, Rushi C; Preda, Rucsanda C; Gil, Eun S; Kaplan, David L; Schmidt, Christine E

    2015-01-01

    Instructive biomaterials capable of controlling the behaviour of the cells are particularly interesting scaffolds for tissue engineering and regenerative medicine. Novel biomaterials are particularly important in societies with rapidly aging populations, where demand for organ/tissue donations is greater than their supply. Herein we describe the preparation of electrically conductive silk film-based nerve tissue scaffolds that are manufactured using all aqueous processing. Aqueous solutions of Bombyx mori silk were cast on flexible polydimethylsiloxane substrates with micrometer-scale grooves on their surfaces, allowed to dry, and annealed to impart β-sheets to the silk which assures that the materials are stable for further processing in water. The silk films were rendered conductive by generating an interpenetrating network of polypyrrole and polystyrenesulfonate in the silk matrix. Films were incubated in an aqueous solution of pyrrole (monomer), polystyrenesulfonate (dopant) and iron chloride (initiator), after which they were thoroughly washed to remove low molecular weight components (monomers, initiators, and oligomers) and dried, yielding conductive films with sheet resistances of 124 ± 23 kΩ square(-1). The micrometer-scale grooves that are present on the surface of the films are analogous to the natural topography in the extracellular matrix of various tissues (bone, muscle, nerve, skin) to which cells respond. Dorsal root ganglions (DRG) adhere to the films and the grooves in the surface of the films instruct the aligned growth of processes extending from the DRG. Such materials potentially enable the electrical stimulation (ES) of cells cultured on them, and future in vitro studies will focus on understanding the interplay between electrical and topographical cues on the behaviour of cells cultured on them.

  20. PEGylated Silk Nanoparticles for Anticancer Drug Delivery.

    Science.gov (United States)

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

    2015-11-09

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

  1. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    OpenAIRE

    Sigal Meirovitch; Zvi Shtein; Tal Ben-Shalom; Shaul Lapidot; Carmen Tamburu; Xiao Hu; Kluge, Jonathan A.; Uri Raviv; Kaplan, David L.; Oded Shoseyov

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhib...

  2. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    OpenAIRE

    Sigal Meirovitch; Zvi Shtein; Tal Ben-Shalom; Shaul Lapidot; Carmen Tamburu; Xiao Hu; Kluge, Jonathan A; Uri Raviv; Kaplan, David L.; Oded Shoseyov

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhib...

  3. Sonication induced silk fibroin cryogels for tissue engineering applications

    Science.gov (United States)

    Kadakia, P. U.; Jain, E.; Hixon, K. R.; Eberlin, C. T.; Sell, S. A.

    2016-05-01

    In this study, we report a method to form macroporous silk fibroin (SF) scaffolds through a combination of ultrasonication followed by cryogelation at subzero temperatures. The resultant sonication induced SF cryogels encompassed larger pore sizes (151 ± 56 μm) and higher mechanical stability (127.15 ± 24.71 kPa) than their hydrogel counterparts made at room temperature. Furthermore, the addition of dopants like Manuka honey and bone char in SF cryogels did not affect cryogel synthesis but decreased the pore size in a concentration dependent manner. With no crack propagation at 50% strain and promising stability under cyclic loads, mineralization and cellular infiltration potential were analyzed for bone tissue engineering purposes. Although the scaffolds showed limited mineralization, encouraging cellular infiltration results yield promise for other tissue engineering applications. The use of mild processing conditions, a simplistic procedure, and the lack of organic solvents or chemical cross-linkers renders the combination of sonication and cryogelation as an attractive fabrication technique for 3D SF macroporous scaffolds.

  4. PEGylated Silk Nanoparticles for Anticancer Drug Delivery

    DEFF Research Database (Denmark)

    Wongpinyochit, Thidarat; Uhlmann, Petra; Urquhart, Andrew

    2015-01-01

    .6 mV) using nanoprecipitation. We then surface grafted polyethylene glycol (PEG) to the fabricated silk nanoparticles and verified the aqueous stability and morphology of the resulting PEGylated silk nanoparticles. We assessed the drug loading and release behavior of these nanoparticles using...... clinically established and emerging anticancer drugs. Overall, PEGylated silk nanoparticles showed high encapsulation efficiency (>93%) and a pH-dependent release over 14 days. Finally, we demonstrated significant cytotoxicity of drug loaded silk nanoparticles applied as single and combination nanomedicines......Silk has a robust clinical track record and is emerging as a promising biopolymer for drug delivery, including its use as nanomedicine. However, silk-based nanomedicines still require further refinements for full exploitation of their potential; the application of “stealth” design principals...

  5. Sunlight-Induced Coloration of Silk

    Science.gov (United States)

    Yao, Ya; Tang, Bin; Chen, Wu; Sun, Lu; Wang, Xungai

    2016-06-01

    Silk fabrics were colored by gold nanoparticles (NPs) that were in situ synthesized through the induction of sunlight. Owing to the localized surface plasmon resonance (LSPR) of gold NPs, the treated silk fabrics presented vivid colors. The photo-induced synthesis of gold NPs was also realized on wet silk through adsorbing gold ions out of solution, which provides a water-saving coloration method for textiles. Besides, the patterning of silk was feasible using this simple sunlight-induced coloration approach. The key factors of coloration including gold ion concentration, pH value, and irradiation time were investigated. Moreover, it was demonstrated that either ultraviolet (UV) light or visible light could induce the generation of gold NPs on silk fabrics. The silk fabrics with gold NPs exhibited high light resistance including great UV-blocking property and excellent fastness to sunlight.

  6. Designing Spider Silk Proteins for Materials Applications

    Science.gov (United States)

    2009-10-28

    WY, 82071-3944 Agreement Number: FA9550-06-1-0368 Project Title: Designing Spider Silk Proteins for Materials Applications REPORT...From - To) 06/2006-010/2009 4. TITLE AND SUBTITLE Designing Spider Silk Proteins for Materials Applications 5a. CONTRACT NUMBER 5b...AVAILABILITY STATEMENT Approved for public release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Spider silks have the

  7. A scaffold-filter model for studying the chondrogenic differentiation of stem cells in vitro.

    Science.gov (United States)

    Zhang, Ling; Zheng, Li; Fan, Hong S; Zhang, Xing D

    2017-01-01

    This study was undertaken to explore the synergistic effect of scaffold materials and a cartilage-like environment on the chondrogenic differentiation of stem cells. Because stem cells encapsulated in a cartilage scaffold will be induced by scaffold molecules as well as permeable molecules from the surroundings, it is impossible to optimize a chondro-inducible scaffold without considering environmental sensitivity. How do we know if a designed scaffold will be sufficient prior to implantation? In this study, bone marrow mesenchymal stem cells (bMSCs) were seeded in various scaffolds, including collagen hydrogel, collage/sodium alginate hydrogel, collagen sponge and silk fibroin sponge. The cell-scaffold complex was encapsulated in a filter pocket to avoid direct contact with co-cultured chondrocytes. Scaffolds differed in the ability to adsorb inducible molecules expressed by chondrocytes, as evidenced by various expressions of cartilage specific proteins and genes. Collagen hydrogel unexpectedly supported chondrogenic differentiation in an environment filled with chondrocytes secretion better than other reinforced scaffolds, which is consistent with the previous experiment in vivo. This result indicated that the environmental sensitivity of a scaffold is important for in vivo chondro-induction. This in vitro scaffold-filter model may be useful as a precursor to investigate the chondro-inducing potential of various scaffolds for cartilage repair.

  8. Change in silk protein by radiation

    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

    2002-03-01

    Silk fibroin fiber irradiated with an accelerated electron beam in the dose range of 250 - 1,000 kGy was pulverized by using a ball mill. As irradiation dose increased, the conversion efficiency from fiber to powder increased, which reached 94% at 1,000 kGy. Silk fibroin powder obtained by this method dissolved 57% into water of ambient temperature. It is a very interesting phenomenon that silk fibroin obtains solubility without chemical treatment. In order to study mechanism of solubilization of silk fibroin powder, amino acid component of soluble part of silk powder was performed. The more irradiation dose up, the more recovery fraction of glycine or alanine decreased, which is, however, reached the minimum about 50%. To consider this result with crystal structure 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 for silk fibroin powder. Molecular weight of soluble part was also measured, but it had no serious concern with irradiation dose. Particle size distribution of silk fibroin powder was measured in order to study reduction of irradiation dose needed for pulverization. This measurement exhibited the possibility that lengthening of pulverization time reduces of irradiation dose. In addition, structure of particle was inferred from result of this measurement. (author)

  9. Antheraea pernyi Silk Fiber: A Potential Resource for Artificially Biospinning Spider Dragline Silk

    Directory of Open Access Journals (Sweden)

    Yaopeng Zhang

    2010-01-01

    Full Text Available The outstanding properties of spider dragline silk are likely to be determined by a combination of the primary sequences and the secondary structure of the silk proteins. Antheraea pernyi silk has more similar sequences to spider dragline silk than the silk from its domestic counterpart, Bombyx mori. This makes it much potential as a resource for biospinning spider dragline silk. This paper further verified its possibility as the resource from the mechanical properties and the structures of the A. pernyi silks prepared by forcible reeling. It is surprising that the stress-strain curves of the A. pernyi fibers show similar sigmoidal shape to those of spider dragline silk. Under a controlled reeling speed of 95 mm/s, the breaking energy was 1.04×105 J/kg, the tensile strength was 639 MPa and the initial modulus was 9.9 GPa. It should be noted that this breaking energy of the A. pernyi silk approaches that of spider dragline silk. The tensile properties, the optical orientation and the β-sheet structure contents of the silk fibers are remarkably increased by raising the spinning speeds up to 95 mm/s.

  10. Luminescent golden silk and fabric through in situ chemically coating pristine-silk with gold nanoclusters.

    Science.gov (United States)

    Zhang, Pu; Lan, Jing; Wang, Yi; Xiong, Zu Hong; Huang, Cheng Zhi

    2015-01-01

    Silk is an excellent natural material and has been used for a variety of applications. Modification of the pristine silk is usually needed depending on the intended purpose. The technical treatments involved in the modification not only should be easy, rapid, environmentally friendly, and cheap but should also retain the features of the pristine silk. Herein, we demonstrate that luminescent silk and fabric can be produced through nanotechnology. The surface of the natural silk fiber is chemically coated with luminescent gold nanoclusters (AuNCs) composed of tens to hundreds of Au atoms through a redox reaction between the protein-based silk and an Au salt precursor. The luminescent silk coated with AuNCs (called golden silk) possesses good optical properties, including a relatively long wavelength emission, high quantum yields, a long fluorescent lifetime, and photostability. Moreover, golden silk prepared this way has better mechanical properties than pristine silk, is better able to inhibit UV, and has lower toxicity in vitro. This work not only provides an effective strategy for in situ preparation of luminescent metal nanoclusters on a solid substrate but also paves the way for large-scale and industrialized production of novel silk-based materials or fabrics through nanotechnology.

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

    Directory of Open Access Journals (Sweden)

    AGATHA AGATHA POPESCU

    2013-10-01

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

  12. Developmental Scaffolding

    DEFF Research Database (Denmark)

    Giorgi, Franco; Bruni, Luis Emilio

    2015-01-01

    . Within the developmental hierarchy, each module yields an inter-level relationship that makes it possible for the scaffolding to mediate the production of selectable variations. Awide range of genetic, cellular and morphological mechanisms allows the scaffolding to integrate these modular variations...... is eventually attained when the embryo acquires the capacity to impose a number of developmental constraints on its constituting parts in a top-down direction. The acquisition of this capacity allows a semiotic threshold to emerge between the living cellular world and the underlying nonliving molecular world...... to the complexity of sign recognition proper of a cellular community. In this semiotic perspective, the apparent goal directness of any developmental strategy should no longer be accounted for by a predetermined genetic program, but by the gradual definition of the relationships selected amongst the ones...

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

    Science.gov (United States)

    Piorkowski, Dakota; Blackledge, Todd A.

    2017-08-01

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

  14. Effect of silk protein surfactant on silk degumming and its properties.

    Science.gov (United States)

    Wang, Fei; Cao, Ting-Ting; Zhang, Yu-Qing

    2015-10-01

    The silk protein surfactant (SPS) first used as a silk degumming agent in this study is an amino acid-type anionic surfactant that was synthesized using silk fibroin amino acids and lauroyl chloride. We studied it systematically in comparison with the traditional degumming methods such as sodium carbonate (Na2CO3) and neutral soap (NS). The experimental results showed that the sericin can be completely removed from the silk fibroin fiber after boiling the fibers three times for 30 min and using a bath ratio of 1:80 (g/mL) and a concentration of 0.2% SPS in an aqueous solution. The results of the tensile properties, thermal analysis, and SEM all show that SPS is similar to the NS, far superior to Na2CO3. In short, SPS may be used as an environmentally friendly silk degumming/refining agent in the silk textile industry and in the manufacture of silk floss quilts.

  15. Revival of the Silk Road

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    China's Xinjiang Uygur Autonomous Region, bordering eight countries and providing a corridor to the Central Asian region, was once famous for the Silk Road. But now this region is often reported by Western media as having the problems of "political separatism, economic exclusion and religious fundamentalism." Professor David Gosset with the Shanghai-based China Europe International Business School analyzed Xinjiang's development, which he framed as "Xinjiang's experience." According to him, Xinjiang has ...

  16. 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

  17. 21 CFR 878.5030 - Natural nonabsorbable silk surgical suture.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Natural nonabsorbable silk surgical suture. 878... Natural nonabsorbable silk surgical suture. (a) Identification. Natural nonabsorbable silk surgical suture... Bombycidae. Natural nonabsorbable silk surgical suture is indicated for use in soft tissue...

  18. Insoluble and flexible silk films containing glycerol.

    Science.gov (United States)

    Lu, Shenzhou; Wang, Xiaoqin; Lu, Qiang; Zhang, Xiaohui; Kluge, Jonathan A; Uppal, Neha; Omenetto, Fiorenzo; Kaplan, David L

    2010-01-11

    We directly prepared insoluble silk films by blending with glycerol and avoiding the use of organic solvents. The ability to blend a plasticizer like glycerol with a hydrophobic protein like silk and achieve stable material systems above a critical threshold of glycerol is an important new finding with importance for green chemistry approaches to new and more flexible silk-based biomaterials. The aqueous solubility, biocompatibility, and well-documented use of glycerol as a plasticizer with other biopolymers prompted its inclusion in silk fibroin solutions to assess impact on silk film behavior. Processing was performed in water rather than organic solvents to enhance the potential biocompatibility of these biomaterials. The films exhibited modified morphologies that could be controlled on the basis of the blend composition and also exhibited altered mechanical properties, such as improved elongation at break, when compared with pure silk fibroin films. Mechanistically, glycerol appears to replace water in silk fibroin chain hydration, resulting in the initial stabilization of helical structures in the films, as opposed to random coil or beta-sheet structures. The use of glycerol in combination with silk fibroin in materials processing expands the functional features attainable with this fibrous protein, and in particular, in the formation of more flexible films with potential utility in a range of biomaterial and device applications.

  19. Biomaterial Scaffolds with Biomimetic Fluidic Channels for Hepatocyte Culture

    Institute of Scientific and Technical Information of China (English)

    Xiao Li; Jiankang He; Yaxiong Liu; Qian Zhao; Wanquan Wu; Dichen Li; Zhongmin Jin

    2013-01-01

    Biomaterial scaffolds play an important role in maintaining the viability and biological functions of highly metabolic hepatocytes in liver tissue engineering.One of the major challenges involves building a complex microchannel network inside three-dimensional (3D) scaffolds for efficient mass transportation.Here we presented a biomimetic strategy to generate a microchannel network within porous biomaterial scaffolds by mimicking the vascular tree of rat liver.The typical parameters of the blood vessels were incorporated into the biomimetic design of the microchannel network such as branching angle and diameter.Silk fibroin-gelatin scaffolds with biomimetic vascular tree were fabricated by combining micromolding,freeze drying and 3D rolling techniques.The relationship between the micro-channeled design and flow pattern was revealed by a flow experiment,which indicated that the scaffolds with biomimetic vascular tree exhibited unique capability in improving mass transportation inside the 3D scaffold.The 3D scaffolds,preseeded with primary hepatocytes,were dynamically cultured in a bioreactor system.The results confirmed that the pre-designed biomimetic microchannel network facilitated the generation and expansion of hepatocytes.

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

    Science.gov (United States)

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

  1. Mechanics and Morphology of Silk Drawn from Anesthetized Spiders

    Science.gov (United States)

    Madsen, B.; Vollrath, F.

    CO2 and N2 anesthetized Nephila spiders produced dragline silk with mechanical properties that differed from control silk as a function of time under anesthesia. Silk from CO2 spiders had a significantly lower breaking strain and breaking energy, significantly higher initial modulus, and marginally lower breaking stress. At the onset of anesthesia the silk diameter became highly variable. During deep anesthesia silk either became thinner or retained cross-section but fibrillated.

  2. Functionalized bioengineered spider silk spheres improve nuclease resistance and activity of oligonucleotide therapeutics providing a strategy for cancer treatment.

    Science.gov (United States)

    Kozlowska, Anna Karolina; Florczak, Anna; Smialek, Maciej; Dondajewska, Ewelina; Mackiewicz, Andrzej; Kortylewski, Marcin; Dams-Kozlowska, Hanna

    2017-09-01

    Cell-selective delivery and sensitivity to serum nucleases remain major hurdles to the clinical application of RNA-based oligonucleotide therapeutics, such as siRNA. Spider silk shows great potential as a biomaterial due to its biocompatibility and biodegradability. Self-assembling properties of silk proteins allow for processing into several different morphologies such as fibers, scaffolds, films, hydrogels, capsules and spheres. Moreover, bioengineering of spider silk protein sequences can functionalize silk by adding peptide moieties with specific features including binding or cell recognition domains. We demonstrated that modification of silk protein by adding the nucleic acid binding domain enabled the development of a novel oligonucleotide delivery system that can be utilized to improve pharmacokinetics of RNA-based therapeutics, such as CpG-siRNA. The MS2 bioengineered silk was functionalized with poly-lysine domain (KN) to generate hybrid silk MS2KN. CpG-siRNA efficiently bound to MS2KN in contrary to control MS2. Both MS2KN complexes and spheres protected CpG-siRNA from degradation by serum nucleases. CpG-siRNA molecules encapsulated into MS2KN spheres were efficiently internalized and processed by TLR9-positive macrophages. Importantly, CpG-STAT3siRNA loaded in silk spheres showed delayed and extended target gene silencing compared to naked oligonucleotides. The prolonged Stat3 silencing resulted in the more pronounced downregulation of interleukin 6 (IL-6), a proinflammatory cytokine and upstream activator of STAT3, which limits the efficacy of TLR9 immunostimulation. Our results demonstrate the feasibility of using spider silk spheres as a carrier of therapeutic nucleic acids. Moreover, the modified kinetic and activity of the CpG-STAT3siRNA embedded into silk spheres is likely to improve immunotherapeutic effects in vivo. We demonstrated that modification of silk protein by adding the nucleic acid binding domain enabled the development of a novel

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

    Science.gov (United States)

    Teulé, Florence; Miao, Yun-Gen; Sohn, Bong-Hee; Kim, Young-Soo; Hull, J Joe; Fraser, Malcolm J; Lewis, Randolph V; Jarvis, Donald L

    2012-01-17

    The development of a spider silk-manufacturing process is of great interest. However, there are serious problems with natural manufacturing through spider farming, and standard recombinant protein production platforms have provided limited progress due to their inability to assemble spider silk proteins into fibers. Thus, we used piggyBac vectors to create transgenic silkworms encoding chimeric silkworm/spider silk proteins. The silk fibers produced by these animals were composite materials that included chimeric silkworm/spider silk proteins integrated in an extremely stable manner. Furthermore, these composite fibers were, on average, tougher than the parental silkworm silk fibers and as tough as native dragline spider silk fibers. These results demonstrate that silkworms can be engineered to manufacture composite silk fibers containing stably integrated spider silk protein sequences, which significantly improve the overall mechanical properties of the parental silkworm silk fibers.

  4. Influence of electrospinning on microstructure of regenerated Argiope bruennichi silk%静电纺再生加工对横纹金珠丝微观结构的影响

    Institute of Scientific and Technical Information of China (English)

    裔婷婷; 潘志娟

    2012-01-01

    蜘蛛丝因其优异的力学性能和良好的生物相容性引起了学者的广泛关注.为此在研究横纹金珠丝在六氟异丙醇(HFIP)中溶解性能的基础上,采用静电纺丝的方法制备再生横纹金珠丝(框丝、卵袋内层丝、卵袋外层丝),分析比较再生横纹金蛛丝和天然横纹金蛛丝在形态结构、分子构象、结晶结构以及热稳定性方面的差异.结果发现:静电纺再生框丝呈扁平带状,带宽为(751±196) nm,卵袋内层丝和卵袋外层丝直径分别为(141±46) nm和(105±37)nm.X衍射图谱和TG-DTA测定结果表明,静电纺再生加工后,横纹金珠丝结构由silkⅡ向silk Ⅰ转变,结晶度下降,主要热分解温度降低.%Spider silk has attracted wide attentions of scholars and researchers due to its excellent mechanical properties and good biocompatibility in recent years. The regenerated Argiope bruennichi silk ( scaffolding silk, egg case inner cover silk, egg case outer cover silk) was prepared by electrospinning on the basis of studying the solubility of Argiope bruennichi silk in 1,1,1,3 ,3 ,3-hexafluoro-2-propanol (HFIP). The morphology, molecular conformation, crystallinity and thermal property of the natural Argiope bruennichi silk and the electrospun Argiope bruennichi silk were compared. The results indicated the electrospun regenerated Argiope bruennichi silk was flat ribbon with the bandwidth ( 751 ± 196 ) nm and a diameter of egg case inner cover silk and egg case outer cover silk (141 ±46) nm and ( 105 ± 37) nm, respectively. The XRD and TG-DTA analysis showed that the crystal structure of electrospun Argiope bruennichi silk has changed from silk II to silk I , and the crystallinity and main thermal decomposition temperature decreased.

  5. Ras1CA overexpression in the posterior silk gland improves silk yield

    Institute of Scientific and Technical Information of China (English)

    Li Ma; Hanfu Xu; Jinqi Zhu; Sanyuan Ma; Yan Liu; Rong-Jing Jiang; Qingyou Xia; Sheng Li

    2011-01-01

    Sericulture has been greatly advanced by applying hybrid breeding techniques to the domesticated silkworm,Bombyx mori,but has reached a plateau during the last decades. For the first time,we report improved silk yield in a GAL4/UAS transgenic silkworm. Overexpression of the Ras1CA oncogene specifically in the posterior silk gland improved fibroin production and silk yield by 60%,while increasing food consumption by only 20%. Ras activation by Ras1CA overexpression in the posterior silk gland enhanced phosphorylation levels of Ras downstream effector proteins,up-regulated fibroin mRNA levels,increased total DNA content,and stimulated endoreplication. Moreover,Rasl activation increased cell and nuclei sizes,enriched subcellular organelles related to protein synthesis,and stimulated ribosome biogenesis for mRNA translation. We conclude that Rasl activation increases cell size and protein synthesis in the posterior silk gland,leading to silk yield improvement.

  6. Silk Spinning in Silkworms and Spiders.

    Science.gov (United States)

    Andersson, Marlene; Johansson, Jan; Rising, Anna

    2016-08-09

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

  7. Spider silk gut: Development and characterization of a novel strong spider silk fiber

    OpenAIRE

    Ping Jiang; Núria Marí-Buyé; Rodrigo Madurga; María Arroyo-Hernández; Concepción Solanas; Alfonso Gañán; Rafael Daza; Plaza, Gustavo R.; Guinea, Gustavo V.; Manuel Elices; José Luis Cenis; José Pérez-Rigueiro

    2014-01-01

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much la...

  8. Silk gene expression of theridiid spiders: implications for male-specific silk use.

    Science.gov (United States)

    Correa-Garhwal, Sandra M; Chaw, R Crystal; Clarke, Thomas H; Ayoub, Nadia A; Hayashi, Cheryl Y

    2017-06-01

    Spiders (order Araneae) rely on their silks for essential tasks, such as dispersal, prey capture, and reproduction. Spider silks are largely composed of spidroins, members of a protein family that are synthesized in silk glands. As needed, silk stored in silk glands is extruded through spigots on the spinnerets. Nearly all studies of spider silks have been conducted on females; thus, little is known about male silk biology. To shed light on silk use by males, we compared silk gene expression profiles of mature males to those of females from three cob-web weaving species (Theridiidae). We de novo assembled species-specific male transcriptomes from Latrodectus hesperus, Latrodectus geometricus, and Steatoda grossa followed by differential gene expression analyses. Consistent with their complement of silk spigots, male theridiid spiders express appreciable amounts of aciniform, major ampullate, minor ampullate, and pyriform spidroin genes but not tubuliform spidroin genes. The relative expression levels of particular spidroin genes varied between sexes and species. Because mature males desert their prey-capture webs and become cursorial in their search for mates, we anticipated that major ampullate (dragline) spidroin genes would be the silk genes most highly expressed by males. Indeed, major ampullate spidroin genes had the highest expression in S. grossa males. However, minor ampullate spidroin genes were the most highly expressed spidroin genes in L. geometricus and L. hesperus males. Our expression profiling results suggest species-specific adaptive divergence of silk use by male theridiids. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  9. Spider silk gut: Development and characterization of a novel strong spider silk fiber

    OpenAIRE

    Ping Jiang; Núria Marí-Buyé; Rodrigo Madurga; María Arroyo-Hernández; Concepción Solanas; Alfonso Gañán; Rafael Daza; Plaza, Gustavo R.; Guinea, Gustavo V.; Manuel Elices; José Luis Cenis; José Pérez-Rigueiro

    2014-01-01

    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much la...

  10. Biomineralization of Engineered Spider Silk Protein-Based Composite Materials for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    John G. Hardy

    2016-07-01

    Full Text Available Materials based on biodegradable polyesters, such as poly(butylene terephthalate (PBT or poly(butylene terephthalate-co-poly(alkylene glycol terephthalate (PBTAT, have potential application as pro-regenerative scaffolds for bone tissue engineering. Herein, the preparation of films composed of PBT or PBTAT and an engineered spider silk protein, (eADF4(C16, that displays multiple carboxylic acid moieties capable of binding calcium ions and facilitating their biomineralization with calcium carbonate or calcium phosphate is reported. Human mesenchymal stem cells cultured on films mineralized with calcium phosphate show enhanced levels of alkaline phosphatase activity suggesting that such composites have potential use for bone tissue engineering.

  11. High-toughness silk produced by a transgenic silkworm expressing spider (Araneus ventricosus dragline silk protein.

    Directory of Open Access Journals (Sweden)

    Yoshihiko Kuwana

    Full Text Available Spider dragline silk is a natural fiber that has excellent tensile properties; however, it is difficult to produce artificially as a long, strong fiber. Here, the spider (Araneus ventricosus dragline protein gene was cloned and a transgenic silkworm was generated, that expressed the fusion protein of the fibroin heavy chain and spider dragline protein in cocoon silk. The spider silk protein content ranged from 0.37 to 0.61% w/w (1.4-2.4 mol% native silkworm fibroin. Using a good silk-producing strain, C515, as the transgenic silkworm can make the raw silk from its cocoons for the first time. The tensile characteristics (toughness of the raw silk improved by 53% after the introduction of spider dragline silk protein; the improvement depended on the quantity of the expressed spider dragline protein. To demonstrate the commercial feasibility for machine reeling, weaving, and sewing, we used the transgenic spider silk to weave a vest and scarf; this was the first application of spider silk fibers from transgenic silkworms.

  12. High-toughness silk produced by a transgenic silkworm expressing spider (Araneus ventricosus) dragline silk protein.

    Science.gov (United States)

    Kuwana, Yoshihiko; Sezutsu, Hideki; Nakajima, Ken-ichi; Tamada, Yasushi; Kojima, Katsura

    2014-01-01

    Spider dragline silk is a natural fiber that has excellent tensile properties; however, it is difficult to produce artificially as a long, strong fiber. Here, the spider (Araneus ventricosus) dragline protein gene was cloned and a transgenic silkworm was generated, that expressed the fusion protein of the fibroin heavy chain and spider dragline protein in cocoon silk. The spider silk protein content ranged from 0.37 to 0.61% w/w (1.4-2.4 mol%) native silkworm fibroin. Using a good silk-producing strain, C515, as the transgenic silkworm can make the raw silk from its cocoons for the first time. The tensile characteristics (toughness) of the raw silk improved by 53% after the introduction of spider dragline silk protein; the improvement depended on the quantity of the expressed spider dragline protein. To demonstrate the commercial feasibility for machine reeling, weaving, and sewing, we used the transgenic spider silk to weave a vest and scarf; this was the first application of spider silk fibers from transgenic silkworms.

  13. THE GREAT SILK ROAD AND TURKISH WORLD

    Directory of Open Access Journals (Sweden)

    Mustafa ÖZDEMİR

    2011-04-01

    Full Text Available The expression of the great Silk Road first came from the famouse Chinese traveler Çjan Syan before the BC and is now known as Kervan Road. Later, this expression gained a new meaning between Asia, the Mediterranean and the European countries.An estimated of 20 000 km of total length of the Great Silk Road passed the Turkish peoples settled lands. The Silk Road that was considered as the Jugularvein major trade route that was connecting China and Byzantium was in Turks hands.

  14. 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.

  15. Nano-composite of silk fibroin-chitosan/Nano ZrO2 for tissue engineering applications: fabrication and morphology.

    Science.gov (United States)

    Teimouri, Abbas; Ebrahimi, Raheleh; Emadi, Rahmatollah; Beni, Batool Hashemi; Chermahini, Alireza Najafi

    2015-05-01

    A scaffold possessing certain desired features such as biodegradation, biocompatibility, and porous structure could serve as a template for tissue engineering. In the present study, silk fibroin (SF), chitosan (CS) and zirconia (Nano ZrO2) were all combined using the freeze drying technique to fabricate a bio-composite scaffold. The composite scaffold (SF/CS/Nano ZrO2) was characterized by SEM, XRD, TGA, BET and FT-IR studies. The scaffold was found to possess a porous nature with pore dimensions suitable for cell infiltration and colonization. The presence of zirconia in the SF/CS/Nano ZrO2 scaffold led to an increase in compressive strength and water uptake capacity while at the same time decreasing the porosity. Cytocompatibility of the SF/CS/Nano ZrO2 scaffold, assessed by MTT assay, revealed non-toxicity to the Human Gingival Fibroblast (HGF, NCBI: C-131). Thus, we suggest that SF/CS/Nano ZrO2 composite scaffold is a potential candidate to be used for tissue engineering.

  16. Capacity of Nylon Industrial Silk Is Surplus

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ The total nylon (polyamide) industrial silk output worldwide was 1.025 million tons in 2005, mostly provided by the producers in Asia, Europe and America, in which the ratio of nylon 6 to nylon 66 was 6:4.

  17. Dynamic behaviour of silks: Nature's precision nanocomposites

    Science.gov (United States)

    Drodge, D. R.; Mortimer, B.; Siviour, C. R.; Holland, C.

    2012-08-01

    Silk is often cited as a material worth imitating, due to its high strength and toughness. In order to produce a synthetic analogue, or enhanced natural version, the microstructural basis of these properties must be understood. Current understanding is that silk deforms through the detachment of nano-scale crystallites, in the manner of a damaged composite. This picture forms the basis for constitutive models, but validation data is limited to low strain-rates. Here we present a programme of research in which high-rate behaviour is studied through ballistic impact experiments. These have been applied to the silk of the Bombyx mori moth, as harvested from cocoons, and to the major ampullate thread of the golden orb weaver spider Nephila edulis. Longitudinal wave-speeds, and air drag coefficients, have been calculated for selected cases. Differences between the response of various silks and a similar synthetic fibre, nylon, are discussed, and future plans are presented.

  18. Chinese Silk in Tibetan Buddhism Monastery

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Chinese traditional silk has held a special place in Chinese tex-tile history as its great contribution to the development of economy and culture of all ethnic groups as well as international exchanges.From time immemorial,

  19. Injectable silk-polyethylene glycol hydrogels.

    Science.gov (United States)

    Wang, Xiaoqin; Partlow, Benjamin; Liu, Jian; Zheng, Zhaozhu; Su, Bo; Wang, Yansong; Kaplan, David L

    2015-01-01

    Silk hydrogels for tissue repair are usually pre-formed via chemical or physical treatments from silk solutions. For many medical applications, it is desirable to utilize injectable silk hydrogels at high concentrations (>8%) to avoid surgical implantation and to achieve slow in vivo degradation of the gel. In the present study, injectable silk solutions that formed hydrogels in situ were generated by mixing silk with low-molecular-weight polyethylene glycol (PEG), especially PEG300 and 400 (molecular weight 300 and 400g mol(-1)). Gelation time was dependent on the concentration and molecular weight of PEG. When the concentration of PEG in the gel reached 40-45%, gelation time was less than 30min, as revealed by measurements of optical density and rheological studies, with kinetics of PEG400 faster than PEG300. Gelation was accompanied by structural changes in silk, leading to the conversion from random coil in solution to crystalline β-sheets in the gels, based on circular dichroism, attenuated total reflection Fourier transform infrared spectroscopy and X-ray diffraction. The modulus (127.5kPa) and yield strength (11.5kPa) determined were comparable to those of sonication-induced hydrogels at the same concentrations of silk. The time-dependent injectability of 15% PEG-silk hydrogel through 27G needles showed a gradual increase of compression forces from ∼10 to 50N within 60min. The growth of human mesenchymal stem cells on the PEG-silk hydrogels was hindered, likely due to the presence of PEG, which grew after a 5 day delay, presumably while the PEG solubilized away from the gel. When 5% PEG-silk hydrogel was subcutaneously injected in rats, significant degradation and tissue in-growth took place after 20 days, as revealed by ultrasound imaging and histological analysis. No significant inflammation around the gel was observed. The features of injectability, slow degradation and low initial cell attachment suggests that these PEG-silk hydrogels are of interest

  20. The Silk Road and Tang Prosperity

    Institute of Scientific and Technical Information of China (English)

    HUOJIANYING

    2003-01-01

    THE dance drama, Along theSilk Road, returned to the Beijing stage for the 2003 Chinese New Year celebrations, to as enthusiastic a receptionas when it was first performed 24years ago. Set in the heyday of theTang Dynasty, the drama celebrates the grotto art of Dunhuang and gorgeous Tang finery. With the ancient Silk Road as a back-drop, its stories extol the love, humanity, and friendship of this essentially open era.

  1. pH-dependent anticancer drug release from silk nanoparticles.

    Science.gov (United States)

    Seib, F Philipp; Jones, Gregory T; Rnjak-Kovacina, Jelena; Lin, Yinan; Kaplan, David L

    2013-12-01

    Silk has traditionally been used as a suture material because of its excellent mechanical properties and biocompatibility. These properties have led to the development of different silk-based material formats for tissue engineering and regenerative medicine. Although there have been a small number of studies about the use of silk particles for drug delivery, none of these studies have assessed the potential of silk to act as a stimulus-responsive anticancer nanomedicine. This report demonstrates that an acetone precipitation of silk allows the formation of uniform silk nanoparticles (98 nm diameter, polydispersity index 0.109), with an overall negative surface charge (-33.6 ± 5.8 mV), in a single step. Silk nanoparticles are readily loaded with doxorubicin (40 ng doxorubicin/μg silk) and show pH-dependent release (pH 4.5≫ 6.0 > 7.4). In vitro studies with human breast cancer cell lines demonstrates that the silk nanoparticles are not cytotoxic (IC50 > 120 μg mL(-1) ) and that doxorubicin-loaded silk nanoparticles are able to overcome drug resistance mechanisms. Live cell fluorescence microscopy studies show endocytic uptake and lysosomal accumulation of silk nanoparticles. In summary, the pH-dependent drug release and lysosomal accumulation of silk nanoparticles demonstrate the ability of drug-loaded silk nanoparticles to serve as a lysosomotropic anticancer nanomedicine.

  2. Electrodeposited silk coatings for bone implants.

    Science.gov (United States)

    Elia, Roberto; Michelson, Courtney D; Perera, Austin L; Brunner, Teresa F; Harsono, Masly; Leisk, Gray G; Kugel, Gerard; Kaplan, David L

    2015-11-01

    The aim of this study was to characterize the mechanical properties and drug elution features of silk protein-based electrodeposited dental implant coatings. Silk processing conditions were modified to obtain coatings with a range of mechanical properties on titanium studs. These coatings were assessed for adhesive strength and dissolution, with properties tuned using water vapor annealing or glycerol incorporation to modulate crystalline content. Coating reproducibility was demonstrated over a range of silk concentrations from 1% to 10%. Surface roughness of titanium substrates was altered using industry relevant acid etching and grit blasting, and the effect of surface topography on silk coating adhesion was assessed. Florescent compounds were incorporated into the silk coatings, which were modulated for crystalline content, to achieve four days of sustained release of the compounds. This silk electrogelation technique offers a safe and relatively simple approach to generate mechanically robust, biocompatible, and degradable implant coatings that can also be functionalized with bioactive compounds to modulate the local regenerative tissue environment.

  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 Roads or Steppe Roads? The Silk Roads in World History.

    Science.gov (United States)

    Christian, David

    2000-01-01

    Explores the prehistory of the Silk Roads, reexamines their structure and history in the classical era, and explores shifts in their geography in the last one thousand years. Explains that a revised understanding of the Silk Roads demonstrates how the Afro-Eurasian land mass has been linked by networks of exchange since the Bronze Age. (CMK)

  5. Production And Characterization Of Synthetic Spider Silks Based On Nephila Clavipes Major Ampullate Silk Proteins

    Science.gov (United States)

    An, Bo

    The extraordinary mechanical properties of orb-weaving spider silks have served spiders for over 400 million years. However, only in the late 20th century did we start to understand the molecular nature of spider silk that contributes to its incredible properties as biomaterials. Among all seven types of spider silks, major ampullate silk from typical orb-weaving spiders is the toughest of all, it consists of primarily two proteins: MaSp1 and MaSp2. Variable ratios and conserved motifs of these two proteins in all the native spider silks demonstrate the significant role of MaSp1 and MaSp2 in controlling the mechanical properties of the fiber. The amino acid sequences of the orb weaving spider silk proteins have remained almost unchanged for more than 100 million years. Interestingly, MaSp1 and MaSp2 are the only two components in all studied dragline silk fibers from these spiders. The mechanical properties of native dragline silk vary slightly between species, which are believed to relate to the ratio of MaSp1 to MaSp2 in the silk. Both of these facts clearly indicate the importance of these two proteins to the mechanical properties of the fiber. Various types of synthetic spider silk fibers have been produced and studied in an effort to mass-produce man-made fibers with qualities comparable to native spider silk. To investigate the roles of MaSp1 and MaSp2 in silk fiber, synthetic MaSp1 (major abundant protein in Nephila clavipes major ampullate silks) only fibers, MaSp1/MaSp2 protein mixture fibers and chimeric protein fibers with both MaSp1 and MaSp2 sequence features have been produced and tested for mechanical properties. Solid-State Nuclear Magnetic Resonance was used to characterize the structure of silk fibers and reveal the relation between fiber spatial structure and mechanical properties.

  6. 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)

  7. 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)

  8. Preparation, characterization and biological test of 3D-scaffolds based on chitosan, fibroin and hydroxyapatite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Paulo Autran Leite; Resende, Cristiane Xavier [Departamento de Ciências de Materiais, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n. Jardim Rosa Elze, São Cristóvão, Sergipe CEP 49000-100 (Brazil); Dulce de Almeida Soares, Glória [Departamento de Ciências de Materiais, Universidade Federal do Rio de Janeiro, Av. Brigadeiro Trompowisk, s/n. Ilha do Fundão, Rio de Janeiro, Rio de Janeiro CEP 21900-000 (Brazil); Anselme, Karine [Institut de Science des Matériaux de Mulhouse (IS2M), CNRS LRC7228, 15, Jean Starcky Street, BP 2488, 68054 Mulhouse cedex (France); Almeida, Luís Eduardo, E-mail: lealmeida2009@gmail.com [Departamento de Ciências de Materiais, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n. Jardim Rosa Elze, São Cristóvão, Sergipe CEP 49000-100 (Brazil)

    2013-08-01

    This work describes the preparation and characterization of porous 3D-scaffolds based on chitosan (CHI), chitosan/silk fibroin (CHI/SF) and chitosan/silk fibroin/hydroxyapatite (CHI/SF/HA) by freeze drying. The biomaterials were characterized by X-ray diffraction, attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and energy dispersive spectroscopy. In addition, studies of porosity, pore size, contact angle and biological response of SaOs-2osteoblastic cells were performed. The CHI scaffolds have a porosity of 94.2 ± 0.9%, which is statistically higher than the one presented by CHI/SF/HA scaffolds, 89.7 ± 2.6%. Although all scaffolds were able to promote adhesion, growth and maintenance of osteogenic differentiation of SaOs-2 cells, the new 3D-scaffold based on CHI/SF/HA showed a significantly higher cell growth at 7 days and 21 days and the level of alkaline phosphatase at 14 and 21 days was statistically superior compared to other tested materials. - Highlights: • Preparation of 3D-scaffolds based on CHI, with or without addition of SF and HA. • Scaffolds exhibited interconnected porous structure (pore size superior to 50 μm). • The tripolyphosphate did not induce any significant cytotoxic response. • The CHI/SF/HA composite showed a higher cell growth and ALP activity.

  9. Rapid Characterization of Spider Silk Genes via Exon Capture

    Science.gov (United States)

    2015-03-28

    eco - friendly than manmade fibers such as nylon and Kevlar, which are industrially manufactured using harsh chemicals and solvents. These...is persistent demand for the mass production of silks, which requires knowledge of the underlying silk gene sequences. Spidroins (spider fibroins...persistent demand for the mass production of silks, which requires knowledge of the underlying silk gene sequences. Spidroins (spider fibroins), the most

  10. Atomic force microscopy of orb-spider-web-silks to measure surface nanostructuring and evaluate silk fibers per strand

    Science.gov (United States)

    Kane, D. M.; Naidoo, N.; Staib, G. R.

    2010-10-01

    Atomic force microscopy (AFM) study is used to measure the surface topology and roughness of radial and capture spider silks on the micro- and nanoscale. This is done for silks of the orb weaver spider Argiope keyserlingi. Capture silk has a surface roughness that is five times less than that for radial silk. The capture silk has an equivalent flatness of λ /100 (5-6 nm deep surface features) as an optical surface. This is equivalent to a very highly polished optical surface. AFM does show the number of silk fibers that make up a silk thread but geometric distortion occurs during sample preparation. This prevented AFM from accurately measuring the silk topology on the microscale in this study.

  11. Silk from crickets: a new twist on spinning.

    Directory of Open Access Journals (Sweden)

    Andrew A Walker

    Full Text Available Raspy crickets (Orthoptera: Gryllacrididae are unique among the orthopterans in producing silk, which is used to build shelters. This work studied the material composition and the fabrication of cricket silk for the first time. We examined silk-webs produced in captivity, which comprised cylindrical fibers and flat films. Spectra obtained from micro-Raman experiments indicated that the silk is composed of protein, primarily in a beta-sheet conformation, and that fibers and films are almost identical in terms of amino acid composition and secondary structure. The primary sequences of four silk proteins were identified through a mass spectrometry/cDNA library approach. The most abundant silk protein was large in size (300 and 220 kDa variants, rich in alanine, glycine and serine, and contained repetitive sequence motifs; these are features which are shared with several known beta-sheet forming silk proteins. Convergent evolution at the molecular level contrasts with development by crickets of a novel mechanism for silk fabrication. After secretion of cricket silk proteins by the labial glands they are fabricated into mature silk by the labium-hypopharynx, which is modified to allow the controlled formation of either fibers or films. Protein folding into beta-sheet structure during silk fabrication is not driven by shear forces, as is reported for other silks.

  12. Post-secretion processing influences spider silk performance

    Science.gov (United States)

    Blamires, Sean J.; Wu, Chung-Lin; Blackledge, Todd A.; Tso, I-Min

    2012-01-01

    Phenotypic variation facilitates adaptations to novel environments. Silk is an example of a highly variable biomaterial. The two-spidroin (MaSp) model suggests that spider major ampullate (MA) silk is composed of two proteins—MaSp1 predominately contains alanine and glycine and forms strength enhancing β-sheet crystals, while MaSp2 contains proline and forms elastic spirals. Nonetheless, mechanical properties can vary in spider silks without congruent amino acid compositional changes. We predicted that post-secretion processing causes variation in the mechanical performance of wild MA silk independent of protein composition or spinning speed across 10 species of spider. We used supercontraction to remove post-secretion effects and compared the mechanics of silk in this ‘ground state’ with wild native silks. Native silk mechanics varied less among species compared with ‘ground state’ silks. Variability in the mechanics of ‘ground state’ silks was associated with proline composition. However, variability in native silks did not. We attribute interspecific similarities in the mechanical properties of native silks, regardless of amino acid compositions, to glandular processes altering molecular alignment of the proteins prior to extrusion. Such post-secretion processing may enable MA silk to maintain functionality across environments, facilitating its function as a component of an insect-catching web. PMID:22628213

  13. Post-secretion processing influences spider silk performance.

    Science.gov (United States)

    Blamires, Sean J; Wu, Chung-Lin; Blackledge, Todd A; Tso, I-Min

    2012-10-07

    Phenotypic variation facilitates adaptations to novel environments. Silk is an example of a highly variable biomaterial. The two-spidroin (MaSp) model suggests that spider major ampullate (MA) silk is composed of two proteins-MaSp1 predominately contains alanine and glycine and forms strength enhancing β-sheet crystals, while MaSp2 contains proline and forms elastic spirals. Nonetheless, mechanical properties can vary in spider silks without congruent amino acid compositional changes. We predicted that post-secretion processing causes variation in the mechanical performance of wild MA silk independent of protein composition or spinning speed across 10 species of spider. We used supercontraction to remove post-secretion effects and compared the mechanics of silk in this 'ground state' with wild native silks. Native silk mechanics varied less among species compared with 'ground state' silks. Variability in the mechanics of 'ground state' silks was associated with proline composition. However, variability in native silks did not. We attribute interspecific similarities in the mechanical properties of native silks, regardless of amino acid compositions, to glandular processes altering molecular alignment of the proteins prior to extrusion. Such post-secretion processing may enable MA silk to maintain functionality across environments, facilitating its function as a component of an insect-catching web.

  14. Use of SERI Surgical Scaffold for Soft-tissue Support in a Massive Weight Loss Patient

    Directory of Open Access Journals (Sweden)

    John E. Gross, MD, FACS

    2013-12-01

    Full Text Available Summary: Patients with a history of massive weight loss have compromised and poor-quality skin and fascia. Various body contouring surgeries aim to improve appearance and shape of the trunk and restore fascial integrity. These patients may be at increased risk of recurrent fascial laxity or bulges after conventional techniques. Here, the author presents a case where a silk-based bioresorbable scaffold was used prophylactically in a massive weight loss patient undergoing a circumferential body lift.

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

    OpenAIRE

    Teulé, Florence; Miao, Yun-Gen; Sohn, Bong-Hee; Kim, Young-Soo; Hull, J. Joe; Fraser, Malcolm J; Lewis, Randolph V.; Jarvis, Donald L.

    2012-01-01

    The development of a spider silk-manufacturing process is of great interest. However, there are serious problems with natural manufacturing through spider farming, and standard recombinant protein production platforms have provided limited progress due to their inability to assemble spider silk proteins into fibers. Thus, we used piggyBac vectors to create transgenic silkworms encoding chimeric silkworm/spider silk proteins. The silk fibers produced by these animals were composite materials t...

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

    OpenAIRE

    Teulé, Florence; Miao, Yun-Gen; Sohn, Bong-Hee; Kim, Young-Soo; Hull, J. Joe; Fraser, Malcolm J.; Lewis, Randolph V.; Jarvis, Donald L.

    2012-01-01

    The development of a spider silk-manufacturing process is of great interest. However, there are serious problems with natural manufacturing through spider farming, and standard recombinant protein production platforms have provided limited progress due to their inability to assemble spider silk proteins into fibers. Thus, we used piggyBac vectors to create transgenic silkworms encoding chimeric silkworm/spider silk proteins. The silk fibers produced by these animals were composite materials t...

  17. Skeletal Muscle Regeneration on Protein-Grafted and Microchannel-Patterned Scaffold for Hypopharyngeal Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Zhisen Shen

    2013-01-01

    Full Text Available In the field of tissue engineering, polymeric materials with high biocompatibility like polylactic acid and polyglycolic acid have been widely used for fabricating living constructs. For hypopharynx tissue engineering, skeletal muscle is one important functional part of the whole organ, which assembles the unidirectionally aligned myotubes. In this study, a polyurethane (PU scaffold with microchannel patterns was used to provide aligning guidance for the seeded human myoblasts. Due to the low hydrophilicity of PU, the scaffold was grafted with silk fibroin (PU-SF or gelatin (PU-Gel to improve its cell adhesion properties. Scaffolds were observed to degrade slowly over time, and their mechanical properties and hydrophilicities were improved through the surface grafting. Also, the myoblasts seeded on PU-SF had the higher proliferative rate and better differentiation compared with those on the control or PU-Gel. Our results demonstrate that polyurethane scaffolds seeded with myoblasts hold promise to guide hypopharynx muscle regeneration.

  18. Skeletal muscle regeneration on protein-grafted and microchannel-patterned scaffold for hypopharyngeal tissue engineering.

    Science.gov (United States)

    Shen, Zhisen; Guo, Shanshan; Ye, Dong; Chen, Jingjing; Kang, Cheng; Qiu, Shejie; Lu, Dakai; Li, Qun; Xu, Kunjie; Lv, Jingjing; Zhu, Yabin

    2013-01-01

    In the field of tissue engineering, polymeric materials with high biocompatibility like polylactic acid and polyglycolic acid have been widely used for fabricating living constructs. For hypopharynx tissue engineering, skeletal muscle is one important functional part of the whole organ, which assembles the unidirectionally aligned myotubes. In this study, a polyurethane (PU) scaffold with microchannel patterns was used to provide aligning guidance for the seeded human myoblasts. Due to the low hydrophilicity of PU, the scaffold was grafted with silk fibroin (PU-SF) or gelatin (PU-Gel) to improve its cell adhesion properties. Scaffolds were observed to degrade slowly over time, and their mechanical properties and hydrophilicities were improved through the surface grafting. Also, the myoblasts seeded on PU-SF had the higher proliferative rate and better differentiation compared with those on the control or PU-Gel. Our results demonstrate that polyurethane scaffolds seeded with myoblasts hold promise to guide hypopharynx muscle regeneration.

  19. High-resolution nanomechanical analysis of suspended electrospun silk fibers with the torsional harmonic atomic force microscope

    Directory of Open Access Journals (Sweden)

    Mark Cronin-Golomb

    2013-04-01

    Full Text Available Atomic force microscopes have become indispensable tools for mechanical characterization of nanoscale and submicron structures. However, materials with complex geometries, such as electrospun fiber networks used for tissue scaffolds, still pose challenges due to the influence of tension and bending modulus on the response of the suspended structures. Here we report mechanical measurements on electrospun silk fibers with various treatments that allow discriminating among the different mechanisms that determine the mechanical behavior of these complex structures. In particular we were able to identify the role of tension and boundary conditions (pinned versus clamped in determining the mechanical response of electrospun silk fibers. Our findings show that high-resolution mechanical imaging with torsional harmonic atomic force microscopy provides a reliable method to investigate the mechanics of materials with complex geometries.

  20. 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.

  1. Impact of silk biomaterial structure on proteolysis.

    Science.gov (United States)

    Brown, Joseph; Lu, Chia-Li; Coburn, Jeannine; Kaplan, David L

    2015-01-01

    The goal of this study was to determine the impact of silk biomaterial structure (e.g. solution, hydrogel, film) on proteolytic susceptibility. In vitro enzymatic degradation of silk fibroin hydrogels and films was studied using a variety of proteases, including proteinase K, protease XIV, α-chymotrypsin, collagenase, matrix metalloproteinase-1 (MMP-1) and MMP-2. Hydrogels were used to assess bulk degradation while films were used to assess surface degradation. Weight loss, secondary structure determined by Fourier transform infrared spectroscopy and degradation products analyzed via sodium dodecyl sulfate-polyacrylamide gel electrophoresis were used to evaluate degradation over 5 days. Silk films were significantly degraded by proteinase K, while silk hydrogels were degraded more extensively by protease XIV and proteinase K. Collagenase preferentially degraded the β-sheet content in hydrogels while protease XIV and α-chymotrypsin degraded the amorphous structures. MMP-1 and MMP-2 degraded silk fibroin in solution, resulting in a decrease in peptide fragment sizes over time. The link between primary sequence mapping with protease susceptibility provides insight into the role of secondary structure in impacting proteolytic access by comparing solution vs. solid state proteolytic susceptibility.

  2. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Ruixin [Institute of Medical Equipment, Academy of Military and Medical Sciences, No. 106, Wandong Street, Hedong District, Tianjin 300000 (China); Jiang, Wenxue, E-mail: jiangortholivea@sina.cn [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Sun, Yufu [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Hui [Tianjin Medical University General Hospital, No. 154 Anshan Road, Tianjin, TJ 300052 (China)

    2016-09-02

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

  3. Control of the gelation process of silk fibroin solution

    Directory of Open Access Journals (Sweden)

    Liu Yu

    2014-01-01

    Full Text Available In the present study, silk fibroin solution was controlled through a simple shearing to accomplish the steady and rapid gelation process and the conformational transition. Antheraea yamamai silk fibroin was formed into hydrogels quicker than Bombyx mori silk fibroin on the same condition. Comparing with Bombyx mori silk fibroin, the rapid gelation of Antheraea yamamai silk fibroin was concerned with its alternate polyalanine-containing units which are tended to form the α-helix structures spontaneously. The entropic cost during the conformational transition to β-sheet is less than that from random coil to β-sheet.

  4. Native spider silk as a biological optical fiber

    Science.gov (United States)

    Huby, N.; Vié, V.; Renault, A.; Beaufils, S.; Lefèvre, T.; Paquet-Mercier, F.; Pézolet, M.; Bêche, B.

    2013-03-01

    In this study, we demonstrate the use of eco-friendly native spider silk as an efficient optical fiber in air, highly bent fibers, and physiological liquid. We also integrated the silk filament in a photonic chip made of polymer microstructures fabricated by UV lithography. The molding process is non-destructive for silk and leads to an efficient micro-optical coupling between silk and synthetic optical structures. These optical performances combined with the unique biocompatibility, bioresorbability, flexibility, and tensile strength of silk filaments pave the way for new applications in biological media and for original biophotonic purposes.

  5. Surface immobilization of antibody on silk fibroin through conformational transition.

    Science.gov (United States)

    Lu, Qiang; Wang, Xiaoqin; Zhu, Hesun; Kaplan, David L

    2011-07-01

    In recent studies silk fibroin has been explored as a new material platform for biosensors. Based on these developments, a procedure for the immobilization of antibodies on silk fibroin substrates was developed as a route to functionalizing these biosensor systems. By controlling the conformational transition of the silk fibroin, a primary antibody was immobilized and enriched at the surface of silk fibroin substrates under mild reaction conditions to maintain antibody function. Compared to chemical crosslinking, the immobilization efficiency in the present approach was increased significantly. This method, achieving high loading of antibody while retaining function, improves the feasibility of silk fibroin as a platform material for biosensor applications.

  6. A Comparison of Tissue Engineering Scaffolds Incorporated with Manuka Honey of Varying UMF

    Directory of Open Access Journals (Sweden)

    Katherine R. Hixon

    2017-01-01

    Full Text Available Purpose. Manuka honey (MH is an antibacterial agent specific to the islands of New Zealand containing both hydrogen peroxide and a Unique Manuka Factor (UMF. Although the antibacterial properties of MH have been studied, the effect of varying UMF of MH incorporated into tissue engineered scaffolds have not. Therefore, this study was designed to compare silk fibroin cryogels and electrospun scaffolds incorporated with a 5% MH concentration of various UMF. Methods. Characteristics such as porosity, bacterial clearance and adhesion, and cytotoxicity were compared. Results. Pore diameters for all cryogels were between 51 and 60 µm, while electrospun scaffolds were 10 µm. Cryogels of varying UMF displayed clearance of approximately 0.16 cm for E. coli and S. aureus. In comparison, the electrospun scaffolds clearance ranged between 0.5 and 1 cm. A glucose release of 0.5 mg/mL was observed for the first 24 hours by all scaffolds, regardless of UMF. With respect to cytotoxicity, neither scaffold caused the cell number to drop below 20,000. Conclusions. Overall, when comparing the effects of the various UMF within the two scaffolds, no significant differences were observed. This suggests that the fabricated scaffolds in this study displayed similar bacterial effects regardless of the UMF value.

  7. Silk fibroin microtubes for blood vessel engineering.

    Science.gov (United States)

    Lovett, Michael; Cannizzaro, Christopher; Daheron, Laurence; Messmer, Brady; Vunjak-Novakovic, Gordana; Kaplan, David L

    2007-12-01

    Currently available synthetic grafts demonstrate moderate success at the macrovascular level, but fail at the microvascular scale (steel wire into aqueous silk fibroin, where the addition of poly(ethylene oxide) (PEO) enabled control of microtube porosity. The microtube properties were characterized in terms of pore size, burst strength, protein permeability, enzymatic degradation, and cell migration. Low porosity microtubes demonstrated superior mechanical properties in terms of higher burst pressures, but displayed poor protein permeability; whereas higher porosity tubes had lower burst strengths but increased permeability and enhanced protein transport. The microtubes also exhibited cellular barrier functions as low porosity tubes prevented outward migration of GFP-transduced HUVECs, while the high porosity microtubes allowed a few cells per tube to migrate outward during perfusion. When combined with the biocompatible and suturability features of silk fibroin, these results suggest that silk microtubes, either implanted directly or preseeded with cells, are an attractive biomaterial for microvascular grafts.

  8. Silk film biomaterials for cornea tissue engineering.

    Science.gov (United States)

    Lawrence, Brian D; Marchant, Jeffrey K; Pindrus, Mariya A; Omenetto, Fiorenzo G; Kaplan, David L

    2009-03-01

    Biomaterials for corneal tissue engineering must demonstrate several critical features for potential utility in vivo, including transparency, mechanical integrity, biocompatibility and slow biodegradation. Silk film biomaterials were designed and characterized to meet these functional requirements. Silk protein films were used in a biomimetic approach to replicate corneal stromal tissue architecture. The films were 2 microm thick to emulate corneal collagen lamellae dimensions, and were surface patterned to guide cell alignment. To enhance trans-lamellar diffusion of nutrients and to promote cell-cell interaction, pores with 0.5-5.0 microm diameters were introduced into the silk films. Human and rabbit corneal fibroblast proliferation, alignment and corneal extracellular matrix expression on these films in both 2D and 3D cultures were demonstrated. The mechanical properties, optical clarity and surface patterned features of these films, combined with their ability to support corneal cell functions suggest that this new biomaterial system offers important potential benefits for corneal tissue regeneration.

  9. 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, Kazushige; Kamiishi, Youichi [Textile Research Inst. of Gunma, Kiryu, Gunma (Japan)

    2000-09-01

    To produce silk fine powder, silk fibroin fibers were irradiated with an accelerated electron beam. Though unirradiated silk fibers were not pulverized at all, irradiated silk fibers were able to be crushed only by physical means using a ball mill. In the dose range of 250- 1000 kGy, as the dose to silk fibroin increased, the conversion rate from fiber to powder was increased. The electron microscope observation showed that the particle size of silk powder was less than 10 micrometers, and that those particles composed aggregate. Although silk fibroin fiber was not soluble in water, silk powders from fiber irradiated 500 kGy dissolved more than 50 weight %. Amino acid analysis of soluble fraction in silk powder showed that Gly content is lower than in normal silk and other amino acids contents except for Ala are 1.5 times as large as in normal silk. From these results, it is reasonable to suppose that irradiation and pulverization decomposed Gly and Ala. (author)

  10. Cell proliferation by silk gut incorporating FGF-2 protein microcrystals.

    Science.gov (United States)

    Kotani, Eiji; Yamamoto, Naoto; Kobayashi, Isao; Uchino, Keiro; Muto, Sayaka; Ijiri, Hiroshi; Shimabukuro, Junji; Tamura, Toshiki; Sezutsu, Hideki; Mori, Hajime

    2015-06-08

    Silk gut processed from the silk glands of the silkworm could be an ideal biodegradable carrier for cell growth factors. We previously demonstrated that polyhedra, microcrystals of Cypovirus 1 polyhedrin, can serve as versatile carrier proteins. Here, we report the generation of a transgenic silkworm that expresses polyhedrin together with human basic fibroblast growth factor (FGF-2) in its posterior silk glands to utilize silk gut as a proteinaceous carrier to protect and slowly release active cell growth factors. In the posterior silk glands, polyhedrin formed polyhedral microcrystals, and FGF-2 became encapsulated within the polyhedra due to a polyhedron-immobilization signal. Silk gut powder prepared from posterior silk glands containing polyhedron-encapsulated FGF-2 stimulated the phosphorylation of p44/p42 MAP kinase and induced the proliferation of serum-starved NIH3T3 cells by releasing bioactive FGF-2. Even after a one-week incubation at 25 °C, significantly higher biological activity of FGF-2 was observed for silk gut powder incorporating polyhedron-encapsulated FGF-2 relative to silk gut powder with non-encapsulated FGF-2. Our results demonstrate that posterior silk glands incorporating polyhedron-encapsulated FGF-2 are applicable to the preparation of biodegradable silk gut, which can protect and release FGF-2 that is produced in a virus- and serum-free expression system with significant application potential.

  11. Spider Silk Spun and Integrated into Composites

    Science.gov (United States)

    2009-02-20

    Vollrath, F. The role of kinetics of water and amide bonding in protein stability Soft Matter , 4 328-336 2008 Holland, C.A. Vollrath F.V. Biomimetic... Soft Matter 2, 448^151 2006 Emile, O. Floch, A.L. Vollrath, F. The self shape-memory effect in spider draglines. Nature 440, 621 2006 Vollrath F...Porter Spider silk as archetypal protein elastomer. Soft Matter 2;377- 385 2006 Vollrath F, Porter, D. Spider silk as a model biomaterial. Applied

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

    Science.gov (United States)

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

    2012-01-01

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

  13. Variation in protein intake induces variation in spider silk expression.

    Directory of Open Access Journals (Sweden)

    Sean J Blamires

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

  14. From silk spinning in insects and spiders to advanced silk fibroin drug delivery systems.

    Science.gov (United States)

    Werner, Vera; Meinel, Lorenz

    2015-11-01

    The natural process of silk spinning covers a fascinating versatility of aggregate states, ranging from colloidal solutions through hydrogels to solid systems. The transition among these states is controlled by a carefully orchestrated process in vivo. Major players within the natural process include the control of spatial pH throughout passage of the silk dope, the composition and type of ions, and fluid flow mechanics within the duct, respectively. The function of these input parameters on the spinning process is reviewed before detailing their impact on the design and manufacture of silk based drug delivery systems (DDS). Examples are reported including the control of hydrogel formation during storage or significant parameters controlling precipitation in the presence of appropriate salts, respectively. The review details the use of silk fibroin (SF) to develop liquid, semiliquid or solid DDS with a focus on the control of SF crystallization, particle formation, and drug-SF interaction for tailored drug load.

  15. 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.

  16. China-Indian Silk Trade: Current Production and Future Prospects

    Institute of Scientific and Technical Information of China (English)

    Liu Feng; Sun Shimin; Qiao Xianjuan

    2009-01-01

    As an important traditional labor-inteusive industry of both India and China, the cocoon silk industry has long made great contributions to the ecological environment protection, rural economic development and the increase in export income of both countries. India is not only a very important cocoon silk trading partner, but an important production competitor of China.In recent years, there has been a large increase in the production and trade of the cocoon silk between China and India; however,China relies heavily on Indian market, which leads to a tendency of further deterioration in the silk trade environment between both countries. The present article makes an empirical study of the cocoon silk resources of the two countries and the scale, product mix and market structure of China-Indian silk trade from 2001 to 2007. Overall silk trading volumes from China to India and market concentration rate are on the increase because of the superiority of Chinese cocoon silk production over that of India. Owing to scat-tered market share and export that mainly focused on raw materi-als product, there has been a phenomenon of price reduction and quantity increase. India carries out fierce competition with China in the international market and even imposes antidumping sanction on Chinese silk, which are key factors restricting further increase between China-India trade. Based on the abovementioned facts, the authors aim to put forward suggestions for steadily developing the production and trade of China's silk.

  17. Mechanical properties of transgenic silkworm silk at high rate impact

    Science.gov (United States)

    Chu, Jou-Mei

    Transgenic silkworm silk was created to obtain the quality of spider silk while being mass-producible. Due to the variability in sequencing between the silkworm and spider DNA, the resulting transgenic silkworm silk may have different properties compared to spider silk. Furthermore, the high strain rate mechanical response of this new natural fiber is still unknown and needs to be characterized. In this experimental research, a quasi-static load frame (MTS) and a Kolsky tension bar are used to characterize the tensile stress-strain response of transgenic silkworm silk over a range of strain-rates between 10-3/s to 103/s. The results show that transgenic silkworm silk tends to have high overall elongation and initial stiffness at high strain rates compared to those of spider silk. Furthermore, specimen gage length sensitivity is studied with gage lengths of 3.97 mm (5/32 in), 4.76 mm (3/16 in), and 6.35 mm (1/4 in). Fracture surfaces are examined via Scanning Electron Microscopy (SEM) and reveal that the fracture mode is similar to that of spider silk. Therefore, it may be possible for the tensile properties of transgenic silkworm silk be comparable to that of spider silk.

  18. Molecular Fundaments of Mechanical Properties of Spider Silk

    Institute of Scientific and Technical Information of China (English)

    潘志娟; 刘敏; 李春萍; 李栋高; 盛家镛

    2003-01-01

    Dragline,framework and cocoon silk fibers of Araneus Ventricosus were used for this study.To investigate the microstructure mechanisms of stress-strain behavior of spider silk,firstly,amino acid compositions were analyzed and molecular conformations and crystallinity were measured with Raman spectra and X-ray diffraction respectively.The results showed that there were more amino acids with large side groups and polar ones in spider silk than those of Bombyx silk,and the amino acid distribution varied with different spider silk.The molecular structures were mainly α-helix and β-sheet,and random coil and β-turn existed as well.The proportions and arrangement of these conformations of dragline silk were different from framework and cocoon silk fibers.Microstructure was one of important factors of excellent mechanical properties of spider silk.Crystallinity of spider silk was very low,which implied that the roles of crystal on spider silk were not as great as other protein fibers.

  19. Structural and optical studies on selected web spinning spider silks

    Science.gov (United States)

    Karthikeyani, R.; Divya, A.; Mathavan, T.; Asath, R. Mohamed; Benial, A. Milton Franklin; Muthuchelian, K.

    2017-01-01

    This study investigates the structural and optical properties in the cribellate silk of the sheet web spider Stegodyphus sarasinorum Karsch (Eresidae) and the combined dragline, viscid silk of the orb-web spiders Argiope pulchella Thorell (Araneidae) and Nephila pilipes Fabricius (Nephilidae). X-ray diffraction (XRD), Fourier transform infra-red (FTIR), Ultraviolet-visible (UV-Vis) and fluorescence spectroscopic techniques were used to study these three spider silk species. X-ray diffraction data are consistent with the amorphous polymer network which is arising from the interaction of larger side chain amino acid contributions due to the poly-glycine rich sequences known to be present in the proteins of cribellate silk. The same amorphous polymer networks have been determined from the combined dragline and viscid silk of orb-web spiders. From FTIR spectra the results demonstrate that, cribellate silk of Stegodyphus sarasinorum, combined dragline viscid silk of Argiope pulchella and Nephila pilipes spider silks are showing protein peaks in the amide I, II and III regions. Further they proved that the functional groups present in the protein moieties are attributed to α-helical and side chain amino acid contributions. The optical properties of the obtained spider silks such as extinction coefficients, refractive index, real and imaginary dielectric constants and optical conductance were studied extensively from UV-Vis analysis. The important fluorescent amino acid tyrosine is present in the protein folding was investigated by using fluorescence spectroscopy. This research would explore the protein moieties present in the spider silks which were found to be associated with α-helix and side chain amino acid contributions than with β-sheet secondary structure and also the optical relationship between the three different spider silks are investigated. Successful spectroscopic knowledge of the internal protein structure and optical properties of the spider silks could

  20. Silk Fibroin for Flexible Electronic Devices.

    Science.gov (United States)

    Zhu, Bowen; Wang, Hong; Leow, Wan Ru; Cai, Yurong; Loh, Xian Jun; Han, Ming-Yong; Chen, Xiaodong

    2016-06-01

    Flexible electronic devices are necessary for applications involving unconventional interfaces, such as soft and curved biological systems, in which traditional silicon-based electronics would confront a mechanical mismatch. Biological polymers offer new opportunities for flexible electronic devices by virtue of their biocompatibility, environmental benignity, and sustainability, as well as low cost. As an intriguing and abundant biomaterial, silk offers exquisite mechanical, optical, and electrical properties that are advantageous toward the development of next-generation biocompatible electronic devices. The utilization of silk fibroin is emphasized as both passive and active components in flexible electronic devices. The employment of biocompatible and biosustainable silk materials revolutionizes state-of-the-art electronic devices and systems that currently rely on conventional semiconductor technologies. Advances in silk-based electronic devices would open new avenues for employing biomaterials in the design and integration of high-performance biointegrated electronics for future applications in consumer electronics, computing technologies, and biomedical diagnosis, as well as human-machine interfaces.

  1. The Ancient Art of Silk Painting

    Science.gov (United States)

    Yonker, Kim

    2010-01-01

    In this article, the author describes a silk-painting project with a sea-creature theme for eighth-grade students. Other themes can be used such as geometric quilt designs, tropical rain forest, large flowers, Art Nouveau motifs, portraits and more. (Contains 2 resources.)

  2. The Application of Tea Dyeing to Silk

    Institute of Scientific and Technical Information of China (English)

    金成嬉

    2001-01-01

    Vegetable dyes are eco-friendly throughout the full production process. A study is conducted with the purpose of assessing the properties of dye extracted from green tea, black tea and the tea tree cultivated and used in Jiang Nan area of China. The extracted dyes are applied with and without mordants on silk fabric and the dyeing properties are evaluated.

  3. 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)

  4. Silk-Screening a la Andy.

    Science.gov (United States)

    Mathes, Len

    2000-01-01

    Describes a project that was used with advanced 11th and 12th grade art students in which they created silk-screen self-portraits in the style of Andy Warhol. Discusses the process of creating the portraits and the activities that concluded the project. Lists the needed materials. (CMK)

  5. Constructing Knowledge with Silk Road Visuals

    Science.gov (United States)

    Bisland, Beverly Milner

    2008-01-01

    In this study a group of elementary teachers use illustrations, rather than written text, to introduce their students to the peoples and places of the ancient silk routes. The illustrations are from two picture books; "Marco Polo," written by Gian Paolo Cesaerani and illustrated by Piero Ventura (1977), and "We're Riding on a…

  6. Preparation of 3-D porous fibroin scaffolds by freeze drying with treatment of methanol solutions

    Institute of Scientific and Technical Information of China (English)

    ZHAN JingLin; SUN XiaoDan; CUI FuZhai; KONG XiangDong

    2007-01-01

    In this study,silk scaffolds with appropriate porous structures were prepared by adjusting solution concentrations and providing treatment with methanol solutions in the way of freeze drying. The effects of the preparation conditions on the microstructures and properties of the scaffolds were discussed. Fibroin solutions with different concentrations of 4,6,8,10 wt% were used respectively to prepare the scaffolds. The effects of the addition of 20 vol% methanol before or after freeze drying to the 4 wt% fibroin solution were investigated. As demonstrated by Scanning Electron Microscope (SEM),the fibroin scaffolds prepared without methanol had porous microstructures composed of thin sheets,and the sizes of the pores decreased with the increase of the fibroin solution concentrations,while the scaffolds prepared in the presence of methanol showed porous microstructures formed by fine-particle aggregates. The porosities and mechanical properties of the prepared fibroin scaffolds under different conditions were tested. The crystalline structures and conformations of the fibroin scaffolds were detected by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).

  7. Electrodeposited silk coatings for functionalized implant applications

    Science.gov (United States)

    Elia, Roberto

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

  8. Biologically improved nanofibrous scaffolds for cardiac tissue engineering.

    Science.gov (United States)

    Bhaarathy, V; Venugopal, J; Gandhimathi, C; Ponpandian, N; Mangalaraj, D; Ramakrishna, S

    2014-11-01

    Nanofibrous structure developed by electrospinning technology provides attractive extracellular matrix conditions for the anchorage, migration and differentiation of stem cells, including those responsible for regenerative medicine. Recently, biocomposite nanofibers consisting of two or more polymeric blends are electrospun more tidily in order to obtain scaffolds with desired functional and mechanical properties depending on their applications. The study focuses on one such an attempt of using copolymer Poly(l-lactic acid)-co-poly (ε-caprolactone) (PLACL), silk fibroin (SF) and Aloe Vera (AV) for fabricating biocomposite nanofibrous scaffolds for cardiac tissue engineering. SEM micrographs of fabricated electrospun PLACL, PLACL/SF and PLACL/SF/AV nanofibrous scaffolds are porous, beadless, uniform nanofibers with interconnected pores and obtained fibre diameter in the range of 459 ± 22 nm, 202 ± 12 nm and 188 ± 16 nm respectively. PLACL, PLACL/SF and PLACL/SF/AV electrospun mats obtained at room temperature with an elastic modulus of 14.1 ± 0.7, 9.96 ± 2.5 and 7.0 ± 0.9 MPa respectively. PLACL/SF/AV nanofibers have more desirable properties to act as flexible cell supporting scaffolds compared to PLACL for the repair of myocardial infarction (MI). The PLACL/SF and PLACL/SF/AV nanofibers had a contact angle of 51 ± 12° compared to that of 133 ± 15° of PLACL alone. Cardiac cell proliferation was increased by 21% in PLACL/SF/AV nanofibers compared to PLACL by day 6 and further increased to 42% by day 9. Confocal analysis for cardiac expression proteins myosin and connexin 43 was observed better by day 9 compared to all other nanofibrous scaffolds. The results proved that the fabricated PLACL/SF/AV nanofibrous scaffolds have good potentiality for the regeneration of infarcted myocardium in cardiac tissue engineering.

  9. 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.

  10. Inkjet printing of silk nest arrays for cell hosting.

    Science.gov (United States)

    Suntivich, Rattanon; Drachuk, Irina; Calabrese, Rossella; Kaplan, David L; Tsukruk, Vladimir V

    2014-04-14

    An inkjet printing approach is presented for the facile fabrication of microscopic arrays of biocompatible silk "nests" capable of hosting live cells for prospective biosensors. The patterning of silk fibroin nests were constructed by the layer-by-layer (LbL) assembly of silk polyelectrolytes chemically modified with poly-(l-lysine) and poly-(l-glutamic acid) side chains. The inkjet-printed silk circular regions with a characteristic "nest" shape had diameters of 70-100 μm and a thickness several hundred nanometers were stabilized by ionic pairing and by the formation of the silk II crystalline secondary structure. These "locked-in" silk nests remained anchored to the substrate during incubation in cell growth media to provide a biotemplated platform for printing-in, immobilization, encapsulation and growth of cells. The process of inkjet-assisted printing is versatile and can be applied on any type of substrate, including rigid and flexible, with scalability and facile formation.

  11. Silk micrococoons for protein stabilisation and molecular encapsulation

    Science.gov (United States)

    Shimanovich, Ulyana; Ruggeri, Francesco S.; de Genst, Erwin; Adamcik, Jozef; Barros, Teresa P.; Porter, David; Müller, Thomas; Mezzenga, Raffaele; Dobson, Christopher M.; Vollrath, Fritz; Holland, Chris; Knowles, Tuomas P. J.

    2017-07-01

    Naturally spun silks generate fibres with unique properties, including strength, elasticity and biocompatibility. Here we describe a microfluidics-based strategy to spin liquid native silk, obtained directly from the silk gland of Bombyx mori silkworms, into micron-scale capsules with controllable geometry and variable levels of intermolecular β-sheet content in their protein shells. We demonstrate that such micrococoons can store internally the otherwise highly unstable liquid native silk for several months and without apparent effect on its functionality. We further demonstrate that these native silk micrococoons enable the effective encapsulation, storage and release of other aggregation-prone proteins, such as functional antibodies. These results show that native silk micrococoons are capable of preserving the full activity of sensitive cargo proteins that can aggregate and lose function under conditions of bulk storage, and thus represent an attractive class of materials for the storage and release of active biomolecules.

  12. Composition and hierarchical organisation of a spider silk.

    Directory of Open Access Journals (Sweden)

    Alexander Sponner

    Full Text Available Albeit silks are fairly well understood on a molecular level, their hierarchical organisation and the full complexity of constituents in the spun fibre remain poorly defined. Here we link morphological defined structural elements in dragline silk of Nephila clavipes to their biochemical composition and physicochemical properties. Five layers of different make-ups could be distinguished. Of these only the two core layers contained the known silk proteins, but all can vitally contribute to the mechanical performance or properties of the silk fibre. Understanding the composite nature of silk and its supra-molecular organisation will open avenues in the production of high performance fibres based on artificially spun silk material.

  13. Adhesion modulation using glue droplet spreading in spider capture silk.

    Science.gov (United States)

    Amarpuri, Gaurav; Zhang, Ci; Blackledge, Todd A; Dhinojwala, Ali

    2017-05-01

    Orb web spiders use sticky capture spiral silk to retain prey in webs. Capture spiral silk is composed of an axial fibre of flagelliform silk covered with glue droplets that are arranged in a beads-on-a-string morphology that allows multiple droplets to simultaneously extend and resist pull off. Previous studies showed that the adhesion of capture silk is responsive to environmental humidity, increasing up to an optimum humidity that varied among different spider species. The maximum adhesion was hypothesized to occur when the viscoelasticity of the glue optimized contributions from glue spreading and bulk cohesion. In this study, we show how glue droplet shape during peeling contributes significantly to capture silk adhesion. Both overspreading and underspreading of glue droplets reduces adhesion through changes in crack propagation and failure regime. Understanding the mechanism of stimuli-responsive adhesion of spider capture silk will lead to new designs for smarter adhesives. © 2017 The Author(s).

  14. Surface and Wetting Properties of Embiopteran (Webspinner) Nanofiber Silk.

    Science.gov (United States)

    Osborn Popp, Thomas M; Addison, J Bennett; Jordan, Jacob S; Damle, Viraj G; Rykaczewski, Konrad; Chang, Shery L Y; Stokes, Grace Y; Edgerly, Janice S; Yarger, Jeffery L

    2016-05-10

    Insects of the order Embioptera, known as embiopterans, embiids, or webspinners, weave silk fibers together into sheets to make shelters called galleries. In this study, we show that silk galleries produced by the embiopteran Antipaluria urichi exhibit a highly hydrophobic wetting state with high water adhesion macroscopically equivalent to the rose petal effect. Specifically, the silk sheets have advancing contact angles above 150°, but receding contact angle approaching 0°. The silk sheets consist of layered fiber bundles with single strands spaced by microscale gaps. Scanning and transmission electron microscopy (SEM, TEM) images of silk treated with organic solvent and gas chromatography mass spectrometry (GC-MS) of the organic extract support the presence of a lipid outer layer on the silk fibers. We use cryogenic SEM to demonstrate that water drops reside on only the first layer of the silk fibers. The area fraction of this sparse outer silk layers is 0.1 to 0.3, which according to the Cassie-Baxter equation yields an effective static contact angle of ∼130° even for a mildly hydrophobic lipid coating. Using high magnification optical imaging of the three phase contact line of a water droplet receding from the silk sheet, we show that the high adhesion of the drop stems from water pinning along bundles of multiple silk fibers. The bundles likely form when the drop contact line is pinned on individual fibers and pulls them together as it recedes. The dynamic reorganization of the silk sheets during the droplet movement leads to formation of "super-pinning sites" that give embiopteran silk one of the strongest adhesions to water of any natural hydrophobic surface.

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

    Science.gov (United States)

    2011-01-01

    Film Assembly of Spider Silk -like Block Copolymers Sreevidhya T. Krishnaji,†,‡ Wenwen Huang,§ Olena Rabotyagova,†,‡ Eugenia Kharlampieva, ) Ikjun Choi...Received November 26, 2010 We report the self-assembly of monolayers of spider silk -like block copolymers. Langmuir isotherms were obtained for a series of...bioengineered variants of the spider silks , and stable monolayers were generated. Langmuir-Blodgett films were prepared by transferring the monolayers

  16. The dynamics of scaffolding

    NARCIS (Netherlands)

    Van Geert, P. L. C.; Steenbeek, H.W.

    2005-01-01

    In this article we have reinterpreted a relatively standard definition of scaffolding in the context of dynamic systems theory. Our main point is that scaffolding cannot be understood outside the context of a dynamic approach of learning and (formal or informal) teaching. We provide a dynamic system

  17. Isolation of a clone encoding a second dragline silk fibroin. Nephila clavipes dragline silk is a two-protein fiber.

    Science.gov (United States)

    Hinman, M B; Lewis, R V

    1992-09-25

    Spider dragline silk is a unique protein fiber possessing both high tensile strength and high elasticity. A partial cDNA clone for one dragline silk protein (Spidroin 1) was previously isolated. However, the predicted amino acid sequence could not account for the amino acid composition of dragline silk. We have isolated a partial cDNA clone for another dragline silk protein (Spidroin 2), demonstrating that dragline silk is composed of multiple proteins. The amino acid sequence exhibits an entirely different repetitive motif than Spidroin 1. Spidroin 2 is predicted to consist of linked beta-turns in proline-rich regions which alternate with beta-sheet regions composed of polyalanine segments. This structure for Spidroin 2 provides a model for dragline silk structure and function.

  18. Silk fibroin membrane used for guided bone tissue regeneration.

    Science.gov (United States)

    Cai, Yurong; Guo, Junmao; Chen, Cen; Yao, Chenxue; Chung, Sung-Min; Yao, Juming; Lee, In-Seop; Kong, Xiangdong

    2017-01-01

    With the aim to develop a novel membrane with an appropriate mechanical property and degradation rate for guided bone tissue regeneration, lyophilized and densified silk fibroin membrane was fabricated and its mechanical behavior as well as biodegradation property were investigated. The osteoconductive potency of the silk fibroin membranes were evaluated in a defect rabbit calvarial model. Silk fibroin membrane showed the modulated biodegradable and mechanical properties via ethanol treatment with different concentration. The membrane could prevent soft tissue invasion from normal tissue healing, and the amounts of new bone and defect closure with silk fibroin membrane were similar to those of commercially available collagen membrane.

  19. Using FTIR spectroscopy to detect sericin on historic silk

    Institute of Scientific and Technical Information of China (English)

    WYETH; Paul

    2010-01-01

    Silks represent some of the most precious ancient and historic textile artefacts in collections worldwide.Their optimum preservation demands an appreciation of their characteristics.One important concern,especially with regard to ancient Chinese silks,is whether the fabrics have been degummed.Silks with remnant sericin gum coating the fibroin fibres would require different conservation protocol.In previous research on aged silks,the presence of sericin has been inferred from amino acid analysis of hydrolysates.In the study reported here,the potential of FTIR spectroscopy to provide a simpler and rapid method of detecting sericin on silk has been investigated.Both fibroin and sericin exhibit singular IR absorptions.Attenuated total reflectance spectroscopy was found to highlight the sericin coating more effectively than transmission and reflectance spectroscopy.Three particular peak intensity ratios were identified which might provide a quantitative estimate of the sericin content of new silk,to a sensitivity of 1%-2%.These were also shown to be valid indicators for the presence of sericin on artificially aged and archaeological silks,although quantitation was now not possible.Besides the peak intensity ratios,two signature peaks were also seen to be useful markers for silk fibroin,and their presence in a spectrum could be used to infer a degummed silk.

  20. Spider Silk as Guiding Biomaterial for Human Model Neurons

    National Research Council Canada - National Science Library

    Roloff, Frank; Strauß, Sarah; Vogt, Peter M; Bicker, Gerd; Radtke, Christine

    2014-01-01

    .... In previous studies, transplantation of decellularized veins filled with spider silk for bridging critical size nerve defects resulted in axonal regeneration and remyelination by invading endogenous Schwann cells...

  1. Structure-Function-Property-Design Interplay in Biopolymers: Spider Silk

    Science.gov (United States)

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

    2013-01-01

    Spider silks have been a focus of research for almost two decades due to their outstanding mechanical and biophysical properties. Recent advances in genetic engineering have led to the synthesis of recombinant spider silks, thus helping to unravel a fundamental understanding of structure-function-property relationships. The relationships between molecular composition, secondary structures, and mechanical properties found in different types of spider silks are described, along with a discussion of artificial spinning of these proteins and their bioapplications, including the role of silks in biomineralization and fabrication of biomaterials with controlled properties. PMID:23962644

  2. Blended Yarns of Modacrylic Fibers with Silk Protein

    Institute of Scientific and Technical Information of China (English)

    江慧

    2001-01-01

    The fiber properties of modacrylic fibers with silk protein and spinning technology for blended knitting yarns are studied. By testing the fiber properties, fiber spinnability is analysed. Modacrylic fibers with silk protein are brittle and have poor cohesion, so the key to process modacrylic fibers with silk protein lies in forming lap and sliver. During opening and carding, low speed is used to decrease fiber damage and the proper static resistant oil is applied to eliminate lapping fibers. Besides, the temperature and relative humidity have to be strictly controlled. The applications of modacrylic fibers with silk protein are also put forward.

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

    Science.gov (United States)

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

    2010-10-07

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

  4. Spider silk: a novel optical fibre for biochemical sensing

    Science.gov (United States)

    Hey Tow, Kenny; Chow, Desmond M.; Vollrath, Fritz; Dicaire, Isabelle; Gheysens, Tom; Thévenaz, Luc

    2015-09-01

    Whilst being thoroughly used in the textile industry and biomedical sector, silk has not yet been exploited for fibre optics-based sensing although silk fibres directly obtained from spiders can guide light and have shown early promises to being sensitive to some solvents. In this communication, a pioneering optical fibre sensor based on spider silk is reported, demonstrating for the first time the use of spider silk as an optical fibre sensor to detect polar solvents such as water, ammonia and acetic acid.

  5. Second-order nonlinear optical microscopy of spider silk

    Science.gov (United States)

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

    2017-06-01

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

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

    Science.gov (United States)

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

    2014-04-01

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

  7. Probing the Impact of Acidification on Spider Silk Assembly Kinetics.

    Science.gov (United States)

    Xu, Dian; Guo, Chengchen; Holland, Gregory P

    2015-07-13

    Spiders utilize fine adjustment of the physicochemical conditions within its silk spinning system to regulate spidroin assembly into solid silk fibers with outstanding mechanical properties. However, the exact mechanism about which this occurs remains elusive and is still hotly debated. In this study, the effect of acidification on spider silk assembly was investigated on native spidroins from the major ampullate (MA) gland fluid excised from Latrodectus hesperus (Black Widow) spiders. Incubating the protein-rich MA silk gland fluid at acidic pH conditions results in the formation of silk fibers that are 10-100 μm in length and ∼2 μm in diameter as judged by optical and electron microscope methods. The in vitro spider silk assembly kinetics were monitored as a function of pH with a (13)C solid-state MAS NMR approach. The results confirm the importance of acidic pH in the spider silk self-assembly process with observation of a sigmoidal nucleation-elongation kinetic profile. The rates of nucleation and elongation as well as the percentage of β-sheet structure in the grown fibers depend on the pH. These results confirm the importance of an acidic pH gradient along the spinning duct for spider silk formation and provide a powerful spectroscopic approach to probe the kinetics of spider silk formation under various biochemical conditions.

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

    Science.gov (United States)

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

    2016-03-01

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

  9. Chemical Modification of Silk Fibers with Ethylene Glycol Dimethacrylate

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-qiang; ZHOU Xiang

    2002-01-01

    Silk fibers have been grafted with ethylene glycol dimethacrylate (EGDMA) and characteristics of the grafted silk fibers were analyzed in relation to the graft yield on the basis of the tensile properties, dyeing behaviour, durability during laundering and solubility of the specimen in NaOH solution. The amount of the acid dye absorbed by the fibers decreased with increasing graft yield, while the value of rating for washing fastness on silk fibers was almost unchanged by the graft treatment. The breaking loads of the fiber were almost unchanged whereas rigidity of the fibers increased after graft treatment. Graft treatment enhanced silk fiber durability during laundering and in NaOH solution.

  10. Reproducing Natural Spider Silks' Copolymer Behavior in Synthetic Silk Mimics

    Energy Technology Data Exchange (ETDEWEB)

    An, Bo; Jenkins, Janelle E; Sampath, Sujatha; Holland, Gregory P; Hinman, Mike; Yarger, Jeffery L; Lewis, Randolph [Wyoming; (Sandia); (Utah SU); (AZU)

    2012-10-30

    Dragline silk from orb-weaving spiders is a copolymer of two large proteins, major ampullate spidroin 1 (MaSp1) and 2 (MaSp2). The ratio of these proteins is known to have a large variation across different species of orb-weaving spiders. NMR results from gland material of two different species of spiders, N. clavipes and A. aurantia, indicates that MaSp1 proteins are more easily formed into β-sheet nanostructures, while MaSp2 proteins form random coil and helical structures. To test if this behavior of natural silk proteins could be reproduced by recombinantly produced spider silk mimic protein, recombinant MaSp1/MaSp2 mixed fibers as well as chimeric silk fibers from MaSp1 and MaSp2 sequences in a single protein were produced based on the variable ratio and conserved motifs of MaSp1 and MaSp2 in native silk fiber. Mechanical properties, solid-state NMR, and XRD results of tested synthetic fibers indicate the differing roles of MaSp1 and MaSp2 in the fiber and verify the importance of postspin stretching treatment in helping the fiber to form the proper spatial structure.

  11. Diverse formulas for spider dragline fibers demonstrated by molecular and mechanical characterization of spitting spider silk.

    Science.gov (United States)

    Correa-Garhwal, Sandra M; Garb, Jessica E

    2014-12-08

    Spider silks have outstanding mechanical properties. Most research has focused on dragline silk proteins (major ampullate spidroins, MaSps) from orb-weaving spiders. Using silk gland expression libraries from the haplogyne spider Scytodes thoracica, we discovered two novel spidroins (S. thoracica fibroin 1 and 2). The amino acid composition of S. thoracica silk glands and dragline fibers suggest that fibroin 1 is the major component of S. thoracica dragline silk. Fibroin 1 is dominated by glycine-alanine motifs, and lacks sequence motifs associated with orb-weaver MaSps. We hypothesize fibroin 2 is a piriform or aciniform silk protein, based on amino acid composition, spigot morphology, and phylogenetic analyses. S. thoracica's dragline silk is less tough than previously reported, but is still comparable to other dragline silks. Our analyses suggest that dragline silk proteins evolved multiple times. This demonstrates that spider dragline silk is more diverse than previously understood, providing alternative high performance silk designs.

  12. Gelation Behaviors and Mechanism of Silk Fibroin According to the Addition of Nitrate Salts

    Directory of Open Access Journals (Sweden)

    Dong Su Im

    2016-10-01

    Full Text Available Silk fibroin (SF is a typical fibrous protein that is secreted by silkworms and spiders. It has been used in a variety of areas, and especially for tissue-engineering scaffolds, due to its sound processability, mechanical properties, biodegradability, and biocompatibility. With respect to gelation, the SF gelation time is long in aqueous solutions, so a novel approach is needed to shorten this time. The solubility of regenerated SF is sound in formic acid (FA, which is a carboxylic acid of the simplest structure. In this study, SF was dissolved in formic acid, and the addition of salts then induced a rapid gelation that accompanied a solution-color change. Based on the gelation behaviors of the SF solution according to different SF and salt concentrations, the gelation mechanism was investigated.

  13. Supracolloidal Assemblies as Sacrificial Templates for Porous Silk-Based Biomaterials

    Directory of Open Access Journals (Sweden)

    John G. Hardy

    2015-08-01

    Full Text Available Tissues in the body are hierarchically structured composite materials with tissue-specific properties. Urea self-assembles via hydrogen bonding interactions into crystalline supracolloidal assemblies that can be used to impart macroscopic pores to polymer-based tissue scaffolds. In this communication, we explain the solvent interactions governing the solubility of urea and thereby the scope of compatible polymers. We also highlight the role of solvent interactions on the morphology of the resulting supracolloidal crystals. We elucidate the role of polymer-urea interactions on the morphology of the pores in the resulting biomaterials. Finally, we demonstrate that it is possible to use our urea templating methodology to prepare Bombyx mori silk protein-based biomaterials with pores that human dermal fibroblasts respond to by aligning with the long axis of the pores. This methodology has potential for application in a variety of different tissue engineering niches in which cell alignment is observed, including skin, bone, muscle and nerve.

  14. Gelation Behaviors and Mechanism of Silk Fibroin According to the Addition of Nitrate Salts.

    Science.gov (United States)

    Im, Dong Su; Kim, Min Hee; Yoon, Young Il; Park, Won Ho

    2016-10-10

    Silk fibroin (SF) is a typical fibrous protein that is secreted by silkworms and spiders. It has been used in a variety of areas, and especially for tissue-engineering scaffolds, due to its sound processability, mechanical properties, biodegradability, and biocompatibility. With respect to gelation, the SF gelation time is long in aqueous solutions, so a novel approach is needed to shorten this time. The solubility of regenerated SF is sound in formic acid (FA), which is a carboxylic acid of the simplest structure. In this study, SF was dissolved in formic acid, and the addition of salts then induced a rapid gelation that accompanied a solution-color change. Based on the gelation behaviors of the SF solution according to different SF and salt concentrations, the gelation mechanism was investigated.

  15. Synthesis of and in vitro and in vivo evaluation of a novel TGF-β1-SF-CS three-dimensional scaffold for bone tissue engineering.

    Science.gov (United States)

    Tong, Shuang; Xu, Da-Peng; Liu, Zi-Mei; Du, Yang; Wang, Xu-Kai

    2016-08-01

    The role of transforming growth factor-β1 (TGF-β1) in normal human fracture healing has been previously demonstrated. The objective of the present study was to examine the biocompatibility of TGF-β1-silk fibroin-chitosan (TGF-β1-SF-CS) three-dimensional (3D) scaffolds in order to construct an ideal scaffold for bone tissue engineering. We added TGF-β1 directly to the SF-CS scaffold to construct a 3D scaffold for the first time, to the best of our knowledge, and performed evaluations to determine whether it may have potential applications as a growth factor delivery device. Bone marrow-derived mesenchymal stem cells (BMSCs) were seeded on the TGF-β1-SF-CS scaffolds and the silk fibroin-chitosan (SF-CS) scaffolds. On the TGF-β1‑SF-CS and the SF-CS scaffolds, the cell adhesion rate increased in a time‑dependent manner. Using a Cell Counting Kit-8 (CCK-8) assay and analyzing the alkaline phosphatase (ALP) expression proved that TGF-β1 significantly enhanced the growth and proliferation of BMSCs on the SF-CS scaffolds in a time-dependent manner. To examine the in vivo biocompatibility and osteogenesis of the TGF-β1‑SF-CS scaffolds, the TGF-β1-SF-CS scaffolds and the SF-CS scaffolds were implanted in rabbit mandibles and studied histologically and microradiographically. The 3D computed tomography (CT) scan and histological examinations of the samples showed that the TGF-β1-SF-CS scaffolds exhibited good biocompatibility and extensive osteoconductivity with the host bone after 8 weeks. Moreover, the introduction of TGF-β1 to the SF-CS scaffolds markedly enhanced the efficiency of new bone formation, and this was confirmed using bone mineral density (BMD) and biomechanical evaluation, particularly at 8 weeks after implantation. We demonstrated that the TGF-β1‑SF-CS scaffolds possessed as good biocompatibility and osteogenesis as the hybrid ones. Taken together, these findings indicate that the TGF-β1-SF-CS scaffolds fulfilled the basic

  16. Regenerated cellulose-silk fibroin blends fibers.

    Science.gov (United States)

    Marsano, Enrico; Corsini, Paola; Canetti, Maurizio; Freddi, Giuliano

    2008-08-15

    Fibers made of cellulose and silk fibroin at different composition were wet spun from solutions by using N-methylmorpholine N-oxide hydrates (NMMO/H(2)O) as solvent and ethanol as coagulant. Different spinning conditions were used. The fibers were characterized by different techniques: FTIR-Raman, scanning electron microscopy, wide-angle x-ray diffraction, DSC analysis. The results evidence a phase separation in the whole blends compositions. The tensile characterization, however, illustrates that the properties of the blends fibers are higher respect to a linear behaviour between the pure polymers, confirming a good compatibility between cellulose and silk fibroin. The fibers containing 75% of cellulose show better mechanical properties than pure cellulose fibers: modulus of about 23 GPa and strength to break of 307 MPa.

  17. Gelation behavior of Antheraea pernyi silk fibroin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The sol-gel transition behavior of Antherae pernyi silk fibroin(Ap-SF) has not been systematically investigated.In this work,the influence of environmental temperature,pH,the concentration of Ap-SF,K+ and Ca2+ on the gelation time,and the structural changes of Ap-SF in sol-gel transformation were studied.The results indicated that the gelation time of the Ap-SF aqueous solution decreased with the increase of the Ap-SF concentration and environmental temperature.The sol-gel transformation of Ap-SF was much more rapid than that of Bombyx mori silk fibroin under the same conditions.The Ap-SF was sensitive to changes in the concentration of Ca2+ and K+.Upon gelation,the random coil structure of the Ap-SF was significantly transformed into the β-sheet structure.

  18. The Story oF Silk

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    IN ancient times Greeks and Ro-mans called China Seres,mean-ing the country of silk.TheChinese invented the breeding ofsilkworms,filature and weaving silk,and they have a beautiful legendabout how it happened.It is said that 5,000 to 6,000years ago China was a tribal societyand people suffered from disastrousfloods.The legendary Chineseancestor Huang Di(Yellow Emper-or),chief of a tribe,married Lei Zu,daughter of Xi Ling Shi.At thattime tribes were being harassed byYan Di,and people’s lives weredisrupted.So everyone could livepeacefully,Huang Di fought anddefeated Yan Di.Later he led hispeople and others to fight,captureand kill Chi You,chief of anotherlarge tribe.After that he becameleader of a league of all the tribes.

  19. A tubular gelatin scaffold capable of the time-dependent controlled release of epidermal growth factor and mitomycin C.

    Science.gov (United States)

    Zhu, Jixiang; Yang, Fanwen; He, Fupo; Tian, Xiumei; Tang, Shuo; Chen, Xiaoming

    2015-11-01

    A tubular gelatin scaffold for the time-dependent controlled release of epidermal growth factor (EGF) and mitomycin C (MMC) was fabricated. EGF was incorporated using silk fibroin carriers, and MMC was planted using polylactide (PLA) microspheres. The relationship between scaffold properties and crosslinking degrees was evaluated. As the crosslinking degree was increased from 23.7% to 65.3%, the mechanical properties of the scaffold obviously improved, and the compressive modulus increased to approximately 65kPa. The mass degradation of the scaffold was also controlled from 9 days to approximately 1 month. In vitro release tests indicated that the scaffold mainly released EGF in the early period and MMC in the later period. Urethral epithelial cells (UECs) and urethral scar derived fibroblast cells (UFCs) were coseeded in the scaffold at a ratio of 1:1. After 9 days of coculture, immunostaining results displayed that the proportion of UECs continuously increased to approximately 71%. These changes in cell proportion were confirmed by the results of Western blot analysis. Therefore, the scaffold promoted the growth but inhibited the regeneration of UFCs. This scaffold for time-dependent controlled release of multiple biofactors may be potentially useful in urethral reconstruction and other tissue engineering studies.

  20. Japanese Silk Road Tour Delegation in Xinjiang

    Institute of Scientific and Technical Information of China (English)

    Zhang; Jiahu

    2013-01-01

    <正>A Silk Road Tour Delegation from Nara,Japan visited Urumqi and Kuqa of Xinjiang from July 24 to 30 and called on the Cultural Relics Bureau of the Xinjiang Autonomous Regional Government and the Xinjiang People’s Association for Friendship with Foreign Countries(XPAFFC).XPAFFC President Muzapar Mijit met them on the evening of July 29.He said that it was quite admirable for the delegation to

  1. Electricity from the Silk Cocoon Membrane

    OpenAIRE

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

    2014-01-01

    Silk cocoon membrane (SCM) is an insect engineered structure. We studied the electrical properties of mulberry (Bombyx mori) and non-mulberry (Tussar, Antheraea mylitta) SCM. When dry, SCM behaves like an insulator. On absorbing moisture, it generates electrical current, which is modulated by temperature. The current flowing across the SCM is possibly ionic and protonic in nature. We exploited the electrical properties of SCM to develop simple energy harvesting devices, which could operate lo...

  2. Silk fibroin nanostructured materials for biomedical applications

    Science.gov (United States)

    Mitropoulos, Alexander N.

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

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

    Directory of Open Access Journals (Sweden)

    James Starrett

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

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

    Science.gov (United States)

    Starrett, James; Garb, Jessica E; Kuelbs, Amanda; Azubuike, Ugochi O; Hayashi, Cheryl Y

    2012-01-01

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

  5. Recombinant protein blends: silk beyond natural design.

    Science.gov (United States)

    Dinjaski, Nina; Kaplan, David L

    2016-06-01

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

  6. Rheological and Mechanical Behavior of Silk Fibroin Reinforced Waterborne Polyurethane

    Directory of Open Access Journals (Sweden)

    Yongzhen Tao

    2016-03-01

    Full Text Available Waterborne polyurethane (WPU is a versatile and environment-friendly material with growing applications in both industry and academia. Silk fibroin (SF is an attractive material known for its structural, biological and hemocompatible properties. The SF reinforced waterborne polyurethane (WPU is a promising scaffold material for tissue engineering applications. In this work, we report synthesis and characterization of a novel nanocomposite using SF reinforced WPU. The rheological behaviors of WPU and WPU-SF dispersions with different solid contents were investigated with steady shear and dynamic oscillatory tests to evaluate the formation of the cross-linked gel structure. The average particle size and the zeta potential of WPU-SF dispersions with different SF content were examined at 25 °C to investigate the interaction between SF and WPU. FTIR, SEM, TEM and tensile testing were performed to study the effects of SF content on the structural morphology and mechanical properties of the resultant composite films. Experimental results revealed formation of gel network in the WPU dispersions at solid contents more than 17 wt %. The conjugate reaction between the WPU and SF as well as the hydrogen bond between them helped in dispersing the SF powder into the WPU matrix as small aggregates. Addition of SF to the WPU also improved the Young’s modulus from 0.30 to 3.91 MPa, tensile strength from 0.56 to 8.94 MPa, and elongation at break from 1067% to 2480%, as SF was increased up to 5 wt %. Thus, significant strengthening and toughening can be achieved by introducing SF powder into the WPU formulations.

  7. Thermal and Structural Properties of Silk Biomaterials Plasticized by Glycerol.

    Science.gov (United States)

    Brown, Joseph E; Davidowski, Stephen K; Xu, Dian; Cebe, Peggy; Onofrei, David; Holland, Gregory P; Kaplan, David L

    2016-12-12

    The molecular interactions of silk materials plasticized using glycerol were studied, as these materials provide options for biodegradable and flexible protein-based systems. Plasticizer interactions with silk were analyzed by thermal, spectroscopic, and solid-state NMR analyses. Spectroscopic analysis implied that glycerol was hydrogen bonded to the peptide matrix, but may be displaced with polar solvents. Solid-state NMR indicated that glycerol induced β-sheet formation in the dried silk materials, but not to the extent of methanol treatment. Fast scanning calorimetry suggested that β-sheet crystal formation in silk-glycerol films appeared to be less organized than in the methanol treated silk films. We propose that glycerol may be simultaneously inducing and interfering with β-sheet formation in silk materials, causing some improper folding that results in less-organized silk II structures even after the glycerol is removed. This difference, along with trace residual glycerol, allows glycerol extracted silk materials to retain more flexibility than methanol processed versions.

  8. 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)

  9. First investigation of spider silk as a braided microsurgical suture.

    Science.gov (United States)

    Kuhbier, Joern W; Reimers, Kerstin; Kasper, Cornelia; Allmeling, Christina; Hillmer, Anja; Menger, Björn; Vogt, Peter M; Radtke, Christine

    2011-05-01

    Inhibition of axonal outgrowth accompanied by neuroma formation appears in microsurgical nerve repair as reaction to common microsuture materials like silk, nylon, or polyglycolic acid. In contrast, recent findings revealed advantages of spider silk fibers in guiding Schwann cells in nerve regeneration. Here, we asked if we could braid microsutures from native spider silk fibers. Microsutures braided of native spider dragline silk were manufactured, containing either 2 × 15 or 3 × 10 single fibres strands. Morphologic appearance was studied and tensile strength and stress-strain ratio (SSR) were calculated. The constructed spider silk sutures showed a median thickness of 25 μm, matching the USP definition of 10-0. Maximum load and tensile strength for both spider silk microsutures were significantly more than 2-fold higher than for nylon suture; SSR was 1.5-fold higher. All values except elasticity were higher in 3 × 10 strand sutures compared to 2 × 15 strand sutures, but not significantly. In this pilot study, we demonstrate the successful manufacture of microsutures from spider silk. With regards to the mechanical properties, these sutures were superior to nylon sutures. As spider silk displays high biocompatibility in nerve regeneration, its usage in microsurgical nerve repair should be considered. Copyright © 2011 Wiley Periodicals, Inc.

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

    NARCIS (Netherlands)

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

    2017-01-01

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

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

    NARCIS (Netherlands)

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

    2017-01-01

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

  12. MODIFICATION OF SILK FIBER via EMULSION GRAFT COPOLYMERIZATION WITH FLUOROACRYLATE

    Institute of Scientific and Technical Information of China (English)

    Zhan-xiong Li; Fei-fei Jin; Ben-wen Cao; Xiao-fei Wang

    2008-01-01

    2,2,3,3,4,4,5,5-Octafluoropentyl acrylate was grafted onto silk fiber in a two-step heterogeneous system through the vinyl bonds of acryloyloxyethyl isocyanate modified on the silk. The grafted copolymer was analyzed by FTIR and WAXD, and the results revealed that the fluoroacrylate was successfully grafted onto silk fiber and the crystalline structure of silk fibroin with β-sheet structure was not changed after graft copolymerization. The FT-IR corrected method was used to simulate the grafting yield onto silk compared with the weight increasing method. The results obtained from these two methods were roughly consistent. The influence of the initiator concentration, monomer concentration, react time and temperature on the graft yield was also investigated. The experimental data of thermogravimetry (TG) and differential thermal analysis (DTA) showed that the thermal stability of the modified silk fibers was improved due to the introduction of fluoroacrylate. In comparison with the untreated silk fibers, the water repellence of the modified silk fibers was also improved.

  13. Visual Literacy with Picture Books: The Silk Road

    Science.gov (United States)

    Bisland, Beverly Milner Lee

    2007-01-01

    The ancient Silk Routes connecting China to Europe across the rugged mountains and deserts of central Asia are one of the primary examples of transculturation in world history. Traders on these routes dealt not only in goods such as silk and horses but also made possible the spread of art forms as well as two major religions, Buddhism and Islam. …

  14. Geographic Perspectives with Elementary Students: The Silk Road

    Science.gov (United States)

    Bisland, Beverly Milner

    2006-01-01

    The purpose of this study is to investigate elementary students' explanations of how physical features of the land influence the location of humanly defined structures including trade routes, such as the silk routes. The silk routes were a series of caravan trade routes that extended from Turkey to China and were located as far south as India and…

  15. Structure and Properties of Silk Fibers Grafted with Vinyl Siloxane Monomer

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Silk fibers were grafted with a novel vinyl siloxane monomer. The properties of silk with different grafting yield were discussed. The results showed that the crease recovery of grafted silk fabric is improved significantly, handle of grafted silk is softer, and grafting has no influence on strength of silk. Graft with low grafting yield has no effect on dyeing properties of silk. The results of IR, SEM photographs and amino acid analysis indicate that the monomer combines with silk fiber by physical sediment and chemical bond, the grafting reactions mainly oecurred on Ser., His. and Arg. of silk fibers, and ester crosslinking forms between silanol and Asp., Glu. of silk molecular side chains. X-ray diffraction patterns of silk fibers suggest that the grafting has no effect on the crystalline regions.

  16. Photoelectric Measurement of the Fineness of Raw Silk

    Institute of Scientific and Technical Information of China (English)

    Wan-chun FEI

    2010-01-01

    In order to precisely measure the diameters for obtaining the fineness of rolling raw silk, the physical features of raw silk are analyzed. By means of Fresnel principle, diffractions caused by different transparent raw silk filaments are analyzed and simulated. Image data of raw silk filament measured by digital CMOS camera are analyzed and processed for obtaining the precise diameters of the filament with the relative error of less than 1%. On the assumption of appropriate elliptic cross-section of the filament, the cross-section area is calculated as the fineness of the filament. Measurement experiments are carried out. Finally, some suggestions are proposed for photoelectric measuring the fineness of raw silk.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-15

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

  18. [Processing and Modification of Recombinant Spider Silk Proteins].

    Science.gov (United States)

    Liu, Bin; Wang, Tao; Liu, Xiaobing; Luo, Yongen

    2015-08-01

    Due to its special sequence structure, spider silk protein has unique physical and chemical properties, mechanical properties and excellent biological properties. With the expansion of the application value of spider silk in many fields as a functional material, progress has been made in the studies on the expression of recombinant spider silk proteins through many host systems by gene recombinant techniques. Recombinant spider silk proteins can be processed into high performance fibers, and a wide range of nonfibrous morphologies. Moreover, for their excellent biocompatibility and low immune response they are ideal for biomedical applications. Here we review the process and mechanism of preparation in vitro, chemistry and genetic engineering modification on recombinant spider silk protein.

  19. The complexity of silk under the spotlight of synthetic biology.

    Science.gov (United States)

    Vollrath, Fritz

    2016-08-15

    For centuries silkworm filaments have been the focus of R&D innovation centred on textile manufacture with high added value. Most recently, silk research has focused on more fundamental issues concerning bio-polymer structure-property-function relationships. This essay outlines the complexity and fundamentals of silk spinning, and presents arguments for establishing this substance as an interesting and important subject at the interface of systems biology (discovery) and synthetic biology (translation). It is argued that silk is a generic class of materials where each type of silk presents a different embodiment of emergent properties that combine genetically determined (anticipatory) and environmentally responsive components. In spiders' webs the various silks have evolved to form the interactive components of an intricate fabric that provides an extended phenotype to the spider's body morphology. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  20. Fabrication of Silk Nanofibres with Needle and Roller Electrospinning Methods

    Directory of Open Access Journals (Sweden)

    Nongnut Sasithorn

    2014-01-01

    Full Text Available In this study, silk nanofibres were prepared by electrospinning from silk fibroin in a mixture of formic acid and calcium chloride. A needle and a rotating cylinder were used as fibre generators in the spinning process. The influences of the spinning electrode and spinning parameters (silk concentration and applied voltage on the spinning process, morphology of the obtained fibres, and the production rate of the spinning process were examined. The concentration of the spinning solution influenced the diameter of the silk electrospun fibres, with an increase in the concentration increasing the diameters of the fibres in both spinning systems. The diameters of the electrospun fibres produced by roller electrospinning were greater than those produced by needle electrospinning. Moreover, increasing the concentration of the silk solution and the applied voltage in the spinning process improved the production rate in roller electrospinning but had less influence on the production rate in needle electrospinning.

  1. Characterization of silk gland ribosomes from a bivoltine caddisfly, Stenopsyche marmorata: translational suppression of a silk protein in cold conditions.

    Science.gov (United States)

    Nomura, Takaomi; Ito, Miho; Kanamori, Mai; Shigeno, Yuta; Uchiumi, Toshio; Arai, Ryoichi; Tsukada, Masuhiro; Hirabayashi, Kimio; Ohkawa, Kousaku

    2016-01-08

    Larval Stenopsyche marmorata constructs food capture nets and fixed retreats underwater using self-produced proteinaceous silk fibers. In the Chikuma River (Nagano Prefecture, Japan) S. marmorata has a bivoltine life cycle; overwintering larvae grow slowly with reduced net spinning activity in winter. We recently reported constant transcript abundance of S. marmorata silk protein 1 (Smsp-1), a core S. marmorata silk fiber component, in all seasons, implying translational suppression in the silk gland during winter. Herein, we prepared and characterized silk gland ribosomes from seasonally collected S. marmorata larvae. Ribosomes from silk glands immediately frozen in liquid nitrogen (LN2) after dissection exhibited comparable translation elongation activity in spring, summer, and autumn. Conversely, silk glands obtained in winter did not contain active ribosomes and Smsp-1. Ribosomes from silk glands immersed in ice-cold physiological saline solution for approximately 4 h were translationally inactive, despite summer collection and Smsp-1 expression. The ribosomal inactivation occurs because of defects in the formation of 80S ribosomes, presumably due to splitting of 60S subunits containing 28S rRNA with central hidden break, in response to cold stress. These results suggest a novel-type ribosome-regulated translation control mechanism.

  2. Solution behavior of synthetic silk peptides and modified recombinant silk proteins

    Science.gov (United States)

    Foo, C. Wong Po; Bini, E.; Huang, J.; Lee, S. Y.; Kaplan, D. L.

    2006-02-01

    Spider dragline silk from Nephila clavipes possesses impressive mechanical properties derived in part from repetitive primary sequence containing polyalanine regions that self-assemble into crystalline β-sheets. In the present study, we have sought to understand more details of redox responses related to conformational transitions of modified silk peptides and a recombinant protein containing encoded methionine triggers. Regardless of the position of the methionine trigger relative to the polyalanine domain, chemical oxidation was rapid and slight increases in the α-helical structure and decreases in the β-sheet and random coil content were observed by CD and FTIR in the assembled silk-like peptides and the recombinant protein. CD results indicated that the decrease in β-sheet and random coil conformations, coupled with the increase in helical content during oxidation, occurred during the first 30 min of the reaction. No further conformational changes occurred after this time and the response was independent of methionine trigger location relative to the penta-alanine domain. These results were confirmed with fluorescence studies. The design, processing and utility of these modified redox triggered silk-like peptides and proteins suggest a range of potential utility, from biomaterials to engineered surface coatings with chemically alterable secondary structure and, thus, properties.

  3. Scaffolds in Tendon Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Umile Giuseppe Longo

    2012-01-01

    Full Text Available Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair.

  4. Comprehensive Proteomic Analysis of Spider Dragline Silk from Black Widows: A Recipe to Build Synthetic Silk Fibers

    Directory of Open Access Journals (Sweden)

    Camille Larracas

    2016-09-01

    Full Text Available The outstanding material properties of spider dragline silk fibers have been attributed to two spidroins, major ampullate spidroins 1 and 2 (MaSp1 and MaSp2. Although dragline silk fibers have been treated with different chemical solvents to elucidate the relationship between protein structure and fiber mechanics, there has not been a comprehensive proteomic analysis of the major ampullate (MA gland, its spinning dope, and dragline silk using a wide range of chaotropic agents, inorganic salts, and fluorinated alcohols to elucidate their complete molecular constituents. In these studies, we perform in-solution tryptic digestions of solubilized MA glands, spinning dope and dragline silk fibers using five different solvents, followed by nano liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS analysis with an Orbitrap Fusion™ Tribrid™. To improve protein identification, we employed three different tryptic peptide fragmentation modes, which included collision-induced dissociation (CID, electron transfer dissociation (ETD, and high energy collision dissociation (HCD to discover proteins involved in the silk assembly pathway and silk fiber. In addition to MaSp1 and MaSp2, we confirmed the presence of a third spidroin, aciniform spidroin 1 (AcSp1, widely recognized as the major constituent of wrapping silk, as a product of dragline silk. Our findings also reveal that MA glands, spinning dope, and dragline silk contain at least seven common proteins: three members of the Cysteine-Rich Protein Family (CRP1, CRP2 and CRP4, cysteine-rich secretory protein 3 (CRISP3, fasciclin and two uncharacterized proteins. In summary, this study provides a proteomic blueprint to construct synthetic silk fibers that most closely mimic natural fibers.

  5. Comprehensive Proteomic Analysis of Spider Dragline Silk from Black Widows: A Recipe to Build Synthetic Silk Fibers.

    Science.gov (United States)

    Larracas, Camille; Hekman, Ryan; Dyrness, Simmone; Arata, Alisa; Williams, Caroline; Crawford, Taylor; Vierra, Craig A

    2016-09-13

    The outstanding material properties of spider dragline silk fibers have been attributed to two spidroins, major ampullate spidroins 1 and 2 (MaSp1 and MaSp2). Although dragline silk fibers have been treated with different chemical solvents to elucidate the relationship between protein structure and fiber mechanics, there has not been a comprehensive proteomic analysis of the major ampullate (MA) gland, its spinning dope, and dragline silk using a wide range of chaotropic agents, inorganic salts, and fluorinated alcohols to elucidate their complete molecular constituents. In these studies, we perform in-solution tryptic digestions of solubilized MA glands, spinning dope and dragline silk fibers using five different solvents, followed by nano liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis with an Orbitrap Fusion™ Tribrid™. To improve protein identification, we employed three different tryptic peptide fragmentation modes, which included collision-induced dissociation (CID), electron transfer dissociation (ETD), and high energy collision dissociation (HCD) to discover proteins involved in the silk assembly pathway and silk fiber. In addition to MaSp1 and MaSp2, we confirmed the presence of a third spidroin, aciniform spidroin 1 (AcSp1), widely recognized as the major constituent of wrapping silk, as a product of dragline silk. Our findings also reveal that MA glands, spinning dope, and dragline silk contain at least seven common proteins: three members of the Cysteine-Rich Protein Family (CRP1, CRP2 and CRP4), cysteine-rich secretory protein 3 (CRISP3), fasciclin and two uncharacterized proteins. In summary, this study provides a proteomic blueprint to construct synthetic silk fibers that most closely mimic natural fibers.

  6. Comprehensive Proteomic Analysis of Spider Dragline Silk from Black Widows: A Recipe to Build Synthetic Silk Fibers

    Science.gov (United States)

    Larracas, Camille; Hekman, Ryan; Dyrness, Simmone; Arata, Alisa; Williams, Caroline; Crawford, Taylor; Vierra, Craig A.

    2016-01-01

    The outstanding material properties of spider dragline silk fibers have been attributed to two spidroins, major ampullate spidroins 1 and 2 (MaSp1 and MaSp2). Although dragline silk fibers have been treated with different chemical solvents to elucidate the relationship between protein structure and fiber mechanics, there has not been a comprehensive proteomic analysis of the major ampullate (MA) gland, its spinning dope, and dragline silk using a wide range of chaotropic agents, inorganic salts, and fluorinated alcohols to elucidate their complete molecular constituents. In these studies, we perform in-solution tryptic digestions of solubilized MA glands, spinning dope and dragline silk fibers using five different solvents, followed by nano liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis with an Orbitrap Fusion™ Tribrid™. To improve protein identification, we employed three different tryptic peptide fragmentation modes, which included collision-induced dissociation (CID), electron transfer dissociation (ETD), and high energy collision dissociation (HCD) to discover proteins involved in the silk assembly pathway and silk fiber. In addition to MaSp1 and MaSp2, we confirmed the presence of a third spidroin, aciniform spidroin 1 (AcSp1), widely recognized as the major constituent of wrapping silk, as a product of dragline silk. Our findings also reveal that MA glands, spinning dope, and dragline silk contain at least seven common proteins: three members of the Cysteine-Rich Protein Family (CRP1, CRP2 and CRP4), cysteine-rich secretory protein 3 (CRISP3), fasciclin and two uncharacterized proteins. In summary, this study provides a proteomic blueprint to construct synthetic silk fibers that most closely mimic natural fibers. PMID:27649139

  7. SERI Surgical Scaffold as an Adjunct to Conventional Brachioplasty

    Directory of Open Access Journals (Sweden)

    Andrew N. Kornstein, MD, FACS

    2014-07-01

    Full Text Available Summary: Although the popularity of longitudinal brachioplasty has grown tremendously in recent years, dealing with the unpredictable scar remains a challenge for the surgeon and the patient. The scar often heals slowly and widens over time, perpetuated by the effects of gravity, body movements, and the thin nature of the superficial fascial system (SFS of the arm. Scar widening may correlate with recurrence of the soft-tissue deformity as the repaired underlying SFS stretches. Therefore, techniques that support and stabilize the SFS are highly desirable for addressing the problematic scar. In the present case, the author used a silk-derived surgical scaffold (SERI as an adjunct to conventional brachioplasty. SERI provided the requisite support for the patient’s SFS, resulting in a faster maturation process and a better-quality scar. This stands in stark contrast to the majority of longitudinal brachioplasty results reported in the medical literature.

  8. Spider Silk: Mother Nature's Bio-Superlens

    Science.gov (United States)

    Monks, James N.; Yan, Bing; Hawkins, Nicholas; Vollrath, Fritz; Wang, Zengbo

    2016-09-01

    This paper demonstrates a possible new microfiber bio near field lens that uses minor ampullate spider silk,spun from the Nephila edulis spider, to create a real time image of a surface using near field optical techniques. The microfiber bio lens is the world's first natural superlens created by exploring biological materials. The resolution of the surface image overcomes the diffraction limit, with the ability to resolve patterns at 100 nm under a standard white light source in reflection mode. This resolution offers further developments in superlens technology and paves the way for new bio optics.

  9. Spider Silk: The Mother Nature's Biological Superlens

    CERN Document Server

    Monks, James N; Wang, Zengbo

    2016-01-01

    This paper demonstrates a possible new microfiber bio near field lens that uses minor ampullate spider silk,spun from the Nephila edulis spider, to create a real time image of a surface using near field optical techniques. The microfiber bio lens is the world's first natural superlens created by exploring biological materials. The resolution of the surface image overcomes the diffraction limit, with the ability to resolve patterns at 100 nm under a standard white light source in reflection mode. This resolution offers further developments in superlens technology and paves the way for new bio optics.

  10. Electricity from the silk cocoon membrane.

    Science.gov (United States)

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

    2014-06-25

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

  11. Electricity from the Silk Cocoon Membrane

    Science.gov (United States)

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

    2014-06-01

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

  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. Evidence for antimicrobial activity associated with common house spider silk

    Directory of Open Access Journals (Sweden)

    Wright Simon

    2012-06-01

    Full Text Available Abstract Background Spider silk is one of the most versatile materials in nature with great strength and flexibility. Native and synthetically produced silk has been used in a wide range of applications including the construction of artificial tendons and as substrates for human cell growth. In the literature there are anecdotal reports that suggest that native spider silk may also have antimicrobial properties. Findings In this study we compared the growth of a Gram positive and a Gram negative bacterium in the presence and absence of silk produced by the common house spider Tegenaria domestica. We demonstrate that native web silk of Tegenaria domestica can inhibit the growth of the Gram positive bacterium, Bacillus subtilis. No significant inhibition of growth was detected against the Gram negative bacterium, Escherichia coli. The antimicrobial effect against B. subtilis appears to be short lived thus the active agent potentially acts in a bacteriostatic rather than bactericidal manner. Treatment of the silk with Proteinase K appears to reduce the ability to inhibit bacterial growth. This is consistent with the active agent including a protein element that is denatured or cleaved by treatment. Tegenaria silk does not appear to inhibit the growth of mammalian cells in vitro thus there is the potential for therapeutic applications.

  14. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-08-01

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

  15. Nanofeatured silk fibroin membranes for dermal wound healing applications.

    Science.gov (United States)

    Karahaliloğlu, Zeynep; Ercan, Batur; Denkbaş, Emir B; Webster, Thomas J

    2015-01-01

    As an effort to create the next generation of improved skin graft materials, in this study, we modified the surfaces of a previously investigated material, silk fibroin, using a NaOH alkaline treatment to obtain a biologically inspired nanofeatured surface morphology. Such surfaces were characterized for roughness, energy, and chemistry. In addition, keratinocyte (skin-forming cells) adhesion and proliferation on such nanofeatured silk fibroin wound dressings were studied in an initial attempt to determine the promotion of an epidermal cover on the wound bed to form a new epidermal barrier. Dermal fibroblast adhesion and proliferation were also studied to assess the ability of nanostructured silk fibroin to replace damaged dermal tissue in chronic wounds (i.e., for diabetic foot ulcers). Results demonstrated for the first time that keratinocyte and fibroblast cell density was greater on nanofeatured silk fibroin membranes compared with non-treated silk fibroin surfaces. The enhancement in cellular functions was correlated with an increase in silk surface nanotopography, wettability and change in chemistry after NaOH treatment. Due to the present promising results, the newly developed nanofeatured silk fibroin membranes are exciting alternative skin graft materials which should be further studied for various skin patch and wound dressing applications.

  16. The processing and heterostructuring of silk with light

    Science.gov (United States)

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

    2017-09-01

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

  17. Binding Quantum Dots to Silk Biomaterials for Optical Sensing

    Directory of Open Access Journals (Sweden)

    Disi Lu

    2015-01-01

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

  18. PLGA Microspheres Incorporated Gelatin Scaffold: Microspheres Modulate Scaffold Properties

    OpenAIRE

    Indranil Banerjee; Debasish Mishra; Maiti, Tapas K.

    2009-01-01

    Freeze drying is one of the popular methods of fabrication for poly(lactide-co-glycolide) (PLGA) microspheres incorporated polymer scaffolds. However, the consequence of microspheres incorporation on physical and biological properties of scaffold has not been studied yet. In this study, attempt has been made to characterize the effect of PLGA microsphere incorporation on the physical properties of freeze-dried gelatin scaffold and its influence on cytocompatibility. Scaffolds loaded with va...

  19. Biologically improved nanofibrous scaffolds for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Bhaarathy, V. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Department of Nanoscience and Technology, School of Physical Sciences, Bharathiar University, Coimbatore 641046 (India); Lee Kong Chian School of Medicine, Nanyang Technological University, 138673 (Singapore); Venugopal, J., E-mail: nnijrv@nus.edu.sg [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Gandhimathi, C. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Ponpandian, N.; Mangalaraj, D. [Department of Nanoscience and Technology, School of Physical Sciences, Bharathiar University, Coimbatore 641046 (India); Ramakrishna, S. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore)

    2014-11-01

    Nanofibrous structure developed by electrospinning technology provides attractive extracellular matrix conditions for the anchorage, migration and differentiation of stem cells, including those responsible for regenerative medicine. Recently, biocomposite nanofibers consisting of two or more polymeric blends are electrospun more tidily in order to obtain scaffolds with desired functional and mechanical properties depending on their applications. The study focuses on one such an attempt of using copolymer Poly(L-lactic acid)-co-poly (ε-caprolactone) (PLACL), silk fibroin (SF) and Aloe Vera (AV) for fabricating biocomposite nanofibrous scaffolds for cardiac tissue engineering. SEM micrographs of fabricated electrospun PLACL, PLACL/SF and PLACL/SF/AV nanofibrous scaffolds are porous, beadless, uniform nanofibers with interconnected pores and obtained fibre diameter in the range of 459 ± 22 nm, 202 ± 12 nm and 188 ± 16 nm respectively. PLACL, PLACL/SF and PLACL/SF/AV electrospun mats obtained at room temperature with an elastic modulus of 14.1 ± 0.7, 9.96 ± 2.5 and 7.0 ± 0.9 MPa respectively. PLACL/SF/AV nanofibers have more desirable properties to act as flexible cell supporting scaffolds compared to PLACL for the repair of myocardial infarction (MI). The PLACL/SF and PLACL/SF/AV nanofibers had a contact angle of 51 ± 12° compared to that of 133 ± 15° of PLACL alone. Cardiac cell proliferation was increased by 21% in PLACL/SF/AV nanofibers compared to PLACL by day 6 and further increased to 42% by day 9. Confocal analysis for cardiac expression proteins myosin and connexin 43 was observed better by day 9 compared to all other nanofibrous scaffolds. The results proved that the fabricated PLACL/SF/AV nanofibrous scaffolds have good potentiality for the regeneration of infarcted myocardium in cardiac tissue engineering. - Highlights: • Fabricated nanofibrous scaffolds are porous, beadless and uniform structures. • PLACL/SF/AV nanofibers improve the

  20. Stabilization and release of enzymes from silk films.

    Science.gov (United States)

    Lu, Qiang; Wang, Xiaoqin; Hu, Xiao; Cebe, Peggy; Omenetto, Fiorenzo; Kaplan, David L

    2010-04-08

    A significant challenge remains to protect protein drugs from inactivation during production, storage, and use. In the present study, the stabilization and release of horseradish peroxidase (HRP) in silk films was investigated. Water-insoluble silk films were prepared under mild aqueous conditions, maintaining the activity of the entrapped enzyme. Depending on film processing and post-processing conditions, HRP retained more than 90% of the initial activity at 4 degrees C, room temperature and 37 degrees C over two months. The stability of protein drugs in silk films is attributed to intermolecular interactions between the silk and the enzymes, based on Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The unique structural feature of silk molecules, periodic hydrophobic-hydrophilic domains, enabled strong interactions with proteins. The entrapped protein was present in two states, untrapped active and trapped inactive forms. The ratio between the two forms varied according to processing conditions. Proteolytic degradation and dissolution of the silk films resulted in the release of the bound enzyme which was otherwise not released by diffusion; enzyme recovered full activity upon release. There was a linear relationship between silk degradation/dissolution and the release of entrapped enzyme. Modifying the secondary structure of the silk matrix and the interactions with the non-crystalline domains resulted in control of the film degradation or dissolution rate, and therefore the release rate of the entrapped enzyme. Based on the above results, silk materials are an intriguing carrier for proteins in terms of both retention of activity and controllable release kinetics from the films.

  1. The effects of corn silk on glycaemic metabolism

    Directory of Open Access Journals (Sweden)

    Han Linna

    2009-11-01

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

  2. Formation of different gold nanostructures by silk nanofibrils

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  3. Novel silk protein barrier membranes for guided bone regeneration.

    Science.gov (United States)

    Smeets, Ralf; Knabe, Christine; Kolk, Andreas; Rheinnecker, Michael; Gröbe, Alexander; Heiland, Max; Zehbe, Rolf; Sachse, Manuela; Große-Siestrup, Christian; Wöltje, Michael; Hanken, Henning

    2016-10-12

    This study assesses the biocompatibility of novel silk protein membranes with and without modification, and evaluates their effect on facilitating bone formation and defect repair in guided bone regeneration. Two calvarian bone defects 12 mm in diameter were created in each of a total of 38 rabbits. Four different types of membranes, (silk-, hydroxyapatite-modified silk-, β-TCP-modified silk- and commonly clinically used collagen-membranes) were implanted to cover one of the two defects in each animal. Histologic analysis did not show any adverse tissue reactions in any of the defect sites indicating good biocompatibility of all silk protein membranes. Histomorphometric and histologic evaluation revealed that collagen and β-TCP modified silk membranes supported bone formation (collagen: bone area fraction p = 0.025; significant; β-TCP modified silk membranes bone area fraction: p = 0.24, not significant), guided bone regeneration and defect bridging. The bone, which had formed in defects covered by β-TCP modified silk membranes, displayed a more advanced stage of bone tissue maturation with restoration of the original calvarial bone microarchitecture when compared to the bone which had formed in defects, for which any of the other test membranes were used. Micro-CT analysis did not reveal any differences in the amount of bone formation between defects with and without membranes. In contrast to the collagen membranes, β-TCP modified silk membranes were visible in all cases and may therefore be advantageous for further supporting bone formation beyond 10 weeks and preventing soft tissue ingrowth from the periphery. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  4. 蚕丝纳米纤维在组织工程领域的研究进展%The Research Progress of Natural Silk nanometer in the Field of Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    陈晓敏; 马霄; 何建新

    2013-01-01

    It is the most critical thing that ideal biomaterial scaffold was provided in the field of tissue engineering.Structure and function of bionics are the most important performance requirements,but bionic design and construction of tissue engineering scaffolds must be implemented by the nanofiber.This article describes the performance characteristics of silk nanofiber and confirmed silk fibroin with excellent properties through domestic and foreign literature such as good biocompatibility,which was wide application in the field of tissue engineering.However,tussah silk is more conducive to cell adhesion and growth compared with silk,therefore,we hypothesized that the use of our unique wild silk to produce fibroin nanofibers by electrostatic spinning,which was expected to achieve new progress in biomedical field.%在组织工程中最为关键的是提供理想的生物材料支架,而结构和功能仿生是组织工程支架最重要的性能要求,但仿生组织工程支架的设计与构建必须由纳米纤维来实现.本文介绍蚕丝纳米纤维的性能特点,并通过国内外文献证实了家蚕丝素具有良好的生物相容性等优良特性,在组织工程领域广泛应用.然而,与家蚕丝相比,野蚕丝更利于细胞的黏附、生长,因此我们推测利用我国特有的野蚕丝素进行静电纺丝制取纳米纤维,有望在生物医学领域获得新的进展.

  5. Spider silk reinforced by graphene or carbon nanotubes

    Science.gov (United States)

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

    2017-09-01

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

  6. High-Q silk fibroin whispering gallery microresonator

    Science.gov (United States)

    Xu, Linhua; Jiang, Xuefeng; Zhao, Guangming; Ma, Ding; Tao, Hu; Liu, Zhiwen; Omenetto, Fiorenzo G.; Yang, Lan

    2016-09-01

    We have experimentally demonstrated an on-chip all-silk fibroin whispering gallery mode microresonator by using a simple molding and solution-casting technique. The quality factors of the fabricated silk protein microresonators are up to 10^5. A high-sensitivity thermal sensor was realized in this silk fibroin microtoroid with sensitivity of 1.17 nm/K, 8 times higher than previous WGM resonator based thermal sensors. This opens the way to fabricate biodegradable and biocompatible protein based microresonators on a flexible chip for biophotonics applications.

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Cecilia Boutry

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

  9. Silken toolkits: biomechanics of silk fibers spun by the orb web spider Argiope argentata (Fabricius 1775).

    Science.gov (United States)

    Blackledge, Todd A; Hayashi, Cheryl Y

    2006-07-01

    Orb-weaving spiders spin five fibrous silks from differentiated glands that contain unique sets of proteins. Despite diverse ecological functions, the mechanical properties of most of these silks are not well characterized. Here, we quantify the mechanical performance of this toolkit of silks for the silver garden spider Argiope argentata. Four silks exhibit viscoelastic behaviour typical of polymers, but differ statistically from each other by up to 250% in performance, giving each silk a distinctive suite of material properties. Major ampullate silk is 50% stronger than other fibers, but also less extensible. Aciniform silk is almost twice as tough as other silks because of high strength and extensibility. Capture spiral silk, coated with aqueous glue, is an order of magnitude stretchier than other silks. Dynamic mechanical properties are qualitatively similar, but quantitatively vary by up to 300% among silks. Storage moduli are initially nearly constant and increase after fiber yield, whereas loss tangents reach maxima of 0.1-0.2 at the yield. The remarkable mechanical diversity of Argiope argentata silks probably results in part from the different molecular structures of fibers and can be related to the specific ecological role of each silk. Our study indicates substantial potential to customize the mechanics of bioengineered silks.

  10. Semiotic scaffolding of multicellularity

    DEFF Research Database (Denmark)

    Hoffmeyer, Jesper

    2015-01-01

    semiotic scaffoldings had to be invented in order to prevent this. While a unicellular self may go on to live practically forever, the multicellular self most often must run through an individuation process ending in the death of the individual. Due to basic differences in cells of plants, fungi...... of fertilization and thereby the need for a whole new set of elaborate semiotic scaffoldings. Multicellularity also opened the door to the formation symbiotic relations where cells with different genomes might collaborate or at least coexist inside the same body. All in all multicellularity led to an enormous...... diversification both of morphology space and the space of sensomotoric elaborations. New means for scaffolding of this expansion and diversification of possible life forms into functional patterns called for a corresponding growth in the space of semiotic tools (chemical processes, heat, light, sound, volatile...

  11. Semiotic Scaffolding in Mathematics

    DEFF Research Database (Denmark)

    Johansen, Mikkel Willum; Misfeldt, Morten

    2015-01-01

    This paper investigates the notion of semiotic scaffolding in relation to mathematics by considering its influence on mathematical activities, and on the evolution of mathematics as a research field. We will do this by analyzing the role different representational forms play in mathematical...... cognition, and more broadly on mathematical activities. In the main part of the paper, we will present and analyze three different cases. For the first case, we investigate the semiotic scaffolding involved in pencil and paper multiplication. For the second case, we investigate how the development of new...... in both mathematical cognition and in the development of mathematics itself, but mathematical cognition cannot itself be reduced to the use of semiotic scaffolding....

  12. Nanorheology of regenerated silk fibroin solution

    Indian Academy of Sciences (India)

    A Raghu; Sharath Ananthamurthy

    2008-06-01

    We have investigated the rheological properties of regenerated silk fibroin (RSF), a viscoelastic material at micro and nano length scales, by video microscopy. We describe here the principles and technique of video microscopy as a tool in such investigations. In this work, polystyrene beads were dispersed in the matrix of RSF polymer and the positions of the embedded beads diffusing were tracked using video microscopy. An optical tweezer was used to transport and locate the bead at any desired site within the micro-volume of the sample, to facilitate the subsequent free-bead video analysis. The position information of the beads was used to obtain the time dependant mean squared displacement (MSD) of the beads in the medium and hence to calculate the dynamic moduli of the medium. We present here the results of rheological measurements of the silk polymer network in solution over a frequency range, whose upper limit is the frame capture rate of our camera at full resolution. The technique is complementary to other microrheological techniques to characterize the material, but additionally enables one to characterize local inhomogeneities in the medium, features that get averaged out in bulk characterization procedures.

  13. Evaluation on Gambiered Guangdong Silk's Ecological Properties

    Institute of Scientific and Technical Information of China (English)

    LI Wei-xian; ZHAO Yao-ming; SHI Yan-ming

    2008-01-01

    To evaluate gambiered Guangdong silk's ecology properties,the raw materials ecology,prttluctien ecology and use ecology are analyzed;and the safety to htmaan is tested according to GB/T18885-2002.Gambiered Gnangdong silk is a kind ofnatural product.All its raw materials are reproducible and degradable natural resources,and it can decompose completely when being discarded.It is comfortable to wear,and easy to dean and dry.It is mainly manufactured by dip-dyeing in dye yam solution,and insohting under the burning sun.The preduction energy is solar,a kind of dean and reproducible energy.The production ptocess is clean and eavironmental friendly.There is neither the utilization of synthetic dyestuff and chemical auxiliary,nor the discharge of environment pollutant,and even the dreg of dye yam is used as fuel.The safety test results show that pH value of water extract,heavy metal content(except for Pb content),color fastness and odor meet the requirouents of GB/T18885-2002 and Okeo-tex standard 100.

  14. [Alternative scaffold proteins].

    Science.gov (United States)

    Petrovskaia, L E; Shingarova, L N; Dolgikh, D A; Kirpichnikov, M P

    2011-01-01

    Review is devoted to the challenging direction in modem molecular biology and bioengineering - the properties of alternative scaffold proteins (ASP) and methods for obtaining ASP binding molecules. ASP molecules incorporate conservative protein core and hypervariable regions, providing for the binding function. Structural classification of ASP includes several types which differ also in their molecular targets and potential applications. Construction of artificial binding proteins on the ASP basis implies a combinatorial library design with subsequent selection of specific binders with the use of phage display or the modem cell-free systems. Alternative binding proteins on non-immunoglobulin scaffolds find broad applications in different fields ofbiotechnology and molecular medicine.

  15. Ultra-high Thermal Conductivity of Spider Silk: Protein Function Study with Controlled Structure Change and Comparison

    Science.gov (United States)

    2016-01-23

    SECURITY CLASSIFICATION OF: In the past three years, we have conducted extensive research to study the structure of spider silks and investigate how the...manually spun spider silks demonstrates that the alignment of the antiparallel beta-sheet crystals in spider silks plays one of the most important...the speed of manual silk spinning, using different silks from the same spider and silks from different types of spiders . 1. REPORT DATE (DD-MM-YYYY

  16. Molecular studies of a novel dragline silk from a nursery web spider, Euprosthenops sp. (Pisauridae).

    Science.gov (United States)

    Pouchkina-Stantcheva, Natalia N; McQueen-Mason, Simon J

    2004-08-01

    Various spider species produce dragline silks with different mechanical properties. The primary structure of silk proteins is thought to contribute to the elasticity and strength of the fibres. Previously published work has demonstrated that the dragline silk of Euprosthenops sp. is stiffer then comparable silk of Nephila edulis, Araneus diadematus and Latrodectus mactans. Our studies of Euprosthenops dragline silk at the molecular level have revealed that nursery web spider fibroin has the highest polyalanine content among previously characterised silks and this is likely to contribute to the superior qualities of pisaurid dragline.

  17. Zibo Daranfang Silk Group:Big Dye House Shines over Silk Road

    Institute of Scientific and Technical Information of China (English)

    Liu Yi

    2011-01-01

    Zibo Daranfang Silk Group is a large-scale joint-stock enterprise,which integrates scientific research,production and trade.It owns ten stock holding and participating companies.It is the only enterprise of weaving,printing and dyeing within China,whose capacity of weaving,scouring and bleaching,printing and dyeing is in the first place of the north area of the Yangze River.

  18. Studies on Application of Aroma Finish on Silk Fabric

    Science.gov (United States)

    Hipparagi, Sanganna Aminappa; Srinivasa, Thirumalappa; Das, Brojeswari; Naik, Subhas Venkatappa; Purushotham, Serampur Parappa

    2016-10-01

    Aromatic treatments on textiles have gained importance in the recent years. In the present article work has been done on fragrance finish application on silk material. Silk is an expensive natural fibre used for apparel purpose and known for its feel and appeal. Incorporation of fragrance material in silk product, will add more value to it. Present work focuses to impart durable aroma finish for silk products to be home washed or subjected to dry cleaning. Microencapsulated aroma chemical has been used for the treatment. Impregnation method, Exhaust method, Dip-Pad-Dry method and Spray method have been used to see the influence of application method on the uptake and performance. Evaluation of the aroma treated material has been done through subjective evaluation as per Odor Intensity Reference Scaling (OIRS). Effect of the aroma finishing on the physical properties of the fabric has also been studied. No adverse effect has been observed on the stiffness of the fabric after the aroma treatment.

  19. Mechanical behaviour and formation process of silkworm silk gut.

    Science.gov (United States)

    Cenis, José L; Madurga, Rodrigo; Aznar-Cervantes, Salvador D; Lozano-Pérez, A Abel; Marí-Buyé, Núria; Meseguer-Olmo, Luis; Plaza, Gustavo R; Guinea, Gustavo V; Elices, Manuel; Del Pozo, Francisco; Pérez-Rigueiro, José

    2015-12-14

    High performance silk fibers were produced directly from the silk glands of silkworms (Bombyx mori) following an alternative route to natural spinning. This route is based on a traditional procedure that consists of soaking the silk glands in a vinegar solution and stretching them by hand leading to the so called silkworm guts. Here we present, to the authors' best knowledge, the first comprehensive study on the formation, properties and microstructure of silkworm gut fibers. Comparison of the tensile properties and microstructural organization of the silkworm guts with those of naturally spun fibers allows gain of a deeper insight into the mechanisms that lead to the formation of the fiber, as well as the relationship between the microstructure and properties of these materials. In this regard, it is proved that an acidic environment and subsequent application of tensile stress in the range of 1000 kPa are sufficient conditions for the formation of a silk fiber.

  20. Ptychographic X-ray Tomography of Silk Fiber Hydration

    DEFF Research Database (Denmark)

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

    2013-01-01

    Studying noninvasively the internal nanoporous structure of a single Tussah silk fiber under different humidity conditions, we demonstrate for the first time the feasibility of in-situ ptychographic tomography. The resulting 3D images of the silk fiber interior, obtained at both dry and humid...... conditions, yield quantitative information about the spatial density variations in the form of detailed maps of the size, shape, and orientation distributions of the nanopores inside the silk fiber, revealing that the fiber swells anisotropically in humid conditions, with the expansion taking place solely...... normal to the fiber axis. Exploiting quantitative information on the fiber’s electron density, hydration was found to proceed through interaction with the silk protein rather than filling of pores....

  1. Water-driven actuation of Ornithoctonus huwena spider silk fibers

    Science.gov (United States)

    Lin, Shuyuan; Zhu, Jia; Li, Xinming; Guo, Yang; Fang, Yaopeng; Cheng, Huanyu; Zhu, Hongwei

    2017-01-01

    Spider silk possesses remarkable mechanical properties and can lift weight effectively. Certain kinds of spider silk have unique response to liquid, especially water, because of their hydrophilic proteins, β-sheet characters, and surface structure. The Ornithoctonus huwena (O. huwena) spider is a unique species because it can be bred artificially and it spins silk whose diameter is in nanometer scale. In this work, we report the "shrink-stretch" behavior of the O. huwena spider silk fibers and show how they can be actuated by water to lift weight over long distance, at a fast speed, and with high efficiency. We further rationalize this behavior by analyzing the mechanical energy of the system. The lifting process is energy-efficient and environmentally friendly, allowing applications in actuators, biomimetic muscles, or hoisting devices.

  2. Unravelling the biodiversity of nanoscale signatures of spider silk fibres

    Science.gov (United States)

    Silva, Luciano P.; Rech, Elibio L.

    2013-12-01

    Living organisms are masters at designing outstanding self-assembled nanostructures through a hierarchical organization of modular proteins. Protein-based biopolymers improved and selected by the driving forces of molecular evolution are among the most impressive archetypes of nanomaterials. One of these biomacromolecules is the myriad of compound fibroins of spider silks, which combine surprisingly high tensile strength with great elasticity. However, no consensus on the nano-organization of spider silk fibres has been reached. Here we explore the biodiversity of spider silk fibres, focusing on nanoscale characterization with high-resolution atomic force microscopy. Our results reveal an evolution of the nanoroughness, nanostiffness, nanoviscoelastic, nanotribological and nanoelectric organization of microfibres, even when they share similar sizes and shapes. These features are related to unique aspects of their molecular structures. The results show that combined nanoscale analyses of spider silks may enable the screening of appropriate motifs for bioengineering synthetic fibres from recombinant proteins.

  3. Dynamic behaviour of silks: Nature’s precision nanocomposites

    Directory of Open Access Journals (Sweden)

    Siviour C.R.

    2012-08-01

    Full Text Available Silk is often cited as a material worth imitating, due to its high strength and toughness. In order to produce a synthetic analogue, or enhanced natural version, the microstructural basis of these properties must be understood. Current understanding is that silk deforms through the detachment of nano-scale crystallites, in the manner of a damaged composite. This picture forms the basis for constitutive models, but validation data is limited to low strain-rates. Here we present a programme of research in which high-rate behaviour is studied through ballistic impact experiments. These have been applied to the silk of the Bombyx mori moth, as harvested from cocoons, and to the major ampullate thread of the golden orb weaver spider Nephila edulis. Longitudinal wave-speeds, and air drag coefficients, have been calculated for selected cases. Differences between the response of various silks and a similar synthetic fibre, nylon, are discussed, and future plans are presented.

  4. Recent advances in production of recombinant spider silk proteins.

    Science.gov (United States)

    Chung, Hannah; Kim, Tae Yong; Lee, Sang Yup

    2012-12-01

    Spider silk has been drawing much attention as a great biomaterial having many applications in biotechnology and biomedicine owing to its several desired material characteristics such as outstanding strength, toughness, and elasticity as well as biodegradability and biocompatibility. With various applications foreseeable in industry, there has been much effort to produce recombinant spider silk protein in large amounts. However, owing to the difficulties in its production using spiders, alternative host systems and engineering methods have been investigated to develop suitable production systems that can efficiently produce spider silk protein. Here, we review recent advances in production of spider silk proteins in various heterologous host systems with focus given on the development of metabolic and cellular engineering strategies. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Jain, Dharamdeep; Sahni, Vasav; Dhinojwala, Ali

    2014-03-01

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

  6. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    NARCIS (Netherlands)

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

    2010-01-01

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

  7. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    NARCIS (Netherlands)

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

    2010-01-01

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

  8. Scaffolding Reading Comprehension Skills

    Science.gov (United States)

    Salem, Ashraf Atta Mohamed Safein

    2017-01-01

    The current study investigates whether English language teachers use scaffolding strategies for developing their students' reading comprehension skills or just for assessing their comprehension. It also tries to demonstrate whether teachers are aware of these strategies or they use them as a matter of habit. A questionnaire as well as structured…

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

    OpenAIRE

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

    2011-01-01

    This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this invest...

  10. Promotion of peripheral nerve regeneration of a peptide compound hydrogel scaffold

    Directory of Open Access Journals (Sweden)

    Wei GJ

    2013-08-01

    Full Text Available Guo-Jun Wei,1 Meng Yao,1 Yan-Song Wang,1 Chang-Wei Zhou,1 De-Yu Wan,1 Peng-Zhen Lei,1 Jian Wen,1 Hong-Wei Lei,2 Da-Ming Dong1 1Department of Orthopaedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China; 2Department of Rheumatology, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China Background: Peripheral nerve injury is a common trauma, but presents a significant challenge to the clinic. Silk-based materials have recently become an important biomaterial for tissue engineering applications due to silk’s biocompatibility and impressive mechanical and degradative properties. In the present study, a silk fibroin peptide (SF16 was designed and used as a component of the hydrogel scaffold for the repair of peripheral nerve injury. Methods: The SF16 peptide’s structure was characterized using spectrophotometry and atomic force microscopy, and the SF16 hydrogel was analyzed using scanning electron microscopy. The effects of the SF16 hydrogel on the viability and growth of live cells was first assessed in vitro, on PC12 cells. The in vivo test model involved the repair of a nerve gap with tubular nerve guides, through which it was possible to identify if the SF16 hydrogel would have the potential to enhance nerve regeneration. In this model physiological saline was set as the negative control, and collagen as the positive control. Walking track analysis and electrophysiological methods were used to evaluate the functional recovery of the nerve at 4 and 8 weeks after surgery. Results: Analysis of the SF16 peptide’s characteristics indicated that it consisted of a well-defined secondary structure and exhibited self-assembly. Results of scanning electron microscopy showed that the peptide based hydrogel may represent a porous scaffold that is viable for repair of peripheral nerve injury. Analysis of cell culture also supported that the hydrogel was an effective

  11. Molecular characterization and evolutionary study of spider tubuliform (eggcase) silk protein.

    Science.gov (United States)

    Tian, Maozhen; Lewis, Randolph V

    2005-06-01

    As a result of hundreds of millions of years of evolution, orb-web-weaving spiders have developed the use of seven different silks produced by different abdominal glands for various functions. Tubuliform silk (eggcase silk) is unique among these spider silks due to its high serine and very low glycine content. In addition, tubuliform silk is the only silk produced just during a short period of time, the reproductive season, in the spider's life. To understand the molecular characteristics of the proteins composing this silk, we constructed tubuliform-gland-specific cDNA libraries from three different spider families, Nephila clavipes, Argiope aurantia, and Araneus gemmoides. Sequencing of tubuliform silk cDNAs reveals the repetitive architecture of its coding sequence and novel amino acid motifs. The inferred protein, tubuliform spidroin 1 (TuSp1), contains highly homogenized repeats in all three spiders. Amino acid composition comparison of the predicted tubuliform silk protein sequence to tubuliform silk indicates that TuSp1 is the major component of tubuliform silk. Repeat unit alignment of TuSp1 among three spider species shows high sequence conservation among tubuliform silk protein orthologue groups. Sequence comparison among TuSp1 repetitive units within species suggests intragenic concerted evolution, presumably through gene conversion and unequal crossover events. Comparative analysis demonstrates that TuSp1 represents a new orthologue in the spider silk gene family.

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

    Science.gov (United States)

    Mao, Cuiping; Zhang, Huihui; Lu, Zhisong

    2017-09-01

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

  13. Piriform spider silk sequences reveal unique repetitive elements.

    Science.gov (United States)

    Perry, David J; Bittencourt, Daniela; Siltberg-Liberles, Jessica; Rech, Elibio L; Lewis, Randolph V

    2010-11-08

    Orb-weaving spider silk fibers are assembled from very large, highly repetitive proteins. The repeated segments contain, in turn, short, simple, and repetitive amino acid motifs that account for the physical and mechanical properties of the assembled fiber. Of the six orb-weaver silk fibroins, the piriform silk that makes the attachment discs, which lashes the joints of the web and attaches dragline silk to surfaces, has not been previously characterized. Piriform silk protein cDNAs were isolated from phage libraries of three species: A. trifasciata , N. clavipes , and N. cruentata . The deduced amino acid sequences from these genes revealed two new repetitive motifs: an alternating proline motif, where every other amino acid is proline, and a glutamine-rich motif of 6-8 amino acids. Similar to other spider silk proteins, the repeated segments are large (>200 amino acids) and highly homogenized within a species. There is also substantial sequence similarity across the genes from the three species, with particular conservation of the repetitive motifs. Northern blot analysis revealed that the mRNA is larger than 11 kb and is expressed exclusively in the piriform glands of the spider. Phylogenetic analysis of the C-terminal regions of the new proteins with published spidroins robustly shows that the piriform sequences form an ortholog group.

  14. Compliant threads maximize spider silk connection strength and toughness.

    Science.gov (United States)

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

    2014-09-06

    Millions of years of evolution have adapted spider webs to achieve a range of functionalities, including the well-known capture of prey, with efficient use of material. One feature that has escaped extensive investigation is the silk-on-silk connection joints within spider webs, particularly from a structural mechanics perspective. We report a joint theoretical and computational analysis of an idealized silk-on-silk fibre junction. By modifying the theory of multiple peeling, we quantitatively compare the performance of the system while systematically increasing the rigidity of the anchor thread, by both scaling the stress-strain response and the introduction of an applied pre-strain. The results of our study indicate that compliance is a virtue-the more extensible the anchorage, the tougher and stronger the connection becomes. In consideration of the theoretical model, in comparison with rigid substrates, a compliant anchorage enormously increases the effective adhesion strength (work required to detach), independent of the adhered thread itself, attributed to a nonlinear alignment between thread and anchor (contact peeling angle). The results can direct novel engineering design principles to achieve possible load transfer from compliant fibre-to-fibre anchorages, be they silk-on-silk or another, as-yet undeveloped, system. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  15. Amorphous Silk Fibroin Membranes for Separation of CO2

    Science.gov (United States)

    Aberg, Christopher M.; Patel, Anand K.; Gil, Eun Seok; Spontak, Richard J.; Hagg, May-Britt

    2009-01-01

    Amorphous silk fibroin has shown promise as a polymeric material derivable from natural sources for making membranes for use in removing CO2 from mixed-gas streams. For most applications of silk fibroin, for purposes other than gas separation, this material is used in its highly crystalline, nearly natural form because this form has uncommonly high tensile strength. However, the crystalline phase of silk fibroin is impermeable, making it necessary to convert the material to amorphous form to obtain the high permeability needed for gas separation. Accordingly, one aspect of the present development is a process for generating amorphous silk fibroin by treating native silk fibroin in an aqueous methanol/salt solution. The resulting material remains self-standing and can be prepared as thin film suitable for permeation testing. The permeability of this material by pure CO2 has been found to be highly improved, and its mixed-gas permeability has been found to exceed the mixed-gas permeabilities of several ultrahigh-CO2-permeable synthetic polymers. Only one of the synthetic polymers poly(trimethylsilylpropyne) [PTMSP] may be more highly permeable by CO2. PTMSP becomes unstable with time, whereas amorphous silk should not, although at the time of this reporting this has not been conclusively proven.

  16. Biomolecular Evidence of Silk from 8,500 Years Ago.

    Science.gov (United States)

    Gong, Yuxuan; Li, Li; Gong, Decai; Yin, Hao; Zhang, Juzhong

    2016-01-01

    Pottery, bone implements, and stone tools are routinely found at Neolithic sites. However, the integrity of textiles or silk is susceptible to degradation, and it is therefore very difficult for such materials to be preserved for 8,000 years. Although previous studies have provided important evidence of the emergence of weaving skills and tools, such as figuline spinning wheels and osseous lamellas with traces of filament winding, there is a lack of direct evidence proving the existence of silk. In this paper, we explored evidence of prehistoric silk fibroin through the analysis of soil samples collected from three tombs at the Neolithic site of Jiahu. Mass spectrometry was employed and integrated with proteomics to characterize the key peptides of silk fibroin. The direct biomolecular evidence reported here showed the existence of prehistoric silk fibroin, which was found in 8,500-year-old tombs. Rough weaving tools and bone needles were also excavated, indicating the possibility that the Jiahu residents may possess the basic weaving and sewing skills in making textile. This finding may advance the study of the history of silk, and the civilization of the Neolithic Age.

  17. Silkomics: Insight into the Silk Spinning Process of Spiders.

    Science.gov (United States)

    Dos Santos-Pinto, José Roberto Aparecido; Garcia, Ana Maria Caviquioli; Arcuri, Helen Andrade; Esteves, Franciele Grego; Salles, Heliana Clara; Lubec, Gert; Palma, Mario Sergio

    2016-04-01

    The proteins from the silk-producing glands were identified using both a bottom-up gel-based proteomic approach as well as from a shotgun proteomic approach. Additionally, the relationship between the functions of identified proteins and the spinning process was studied. A total of 125 proteins were identified in the major ampullate, 101 in the flagelliform, 77 in the aggregate, 75 in the tubuliform, 68 in the minor ampullate, and 23 in aciniform glands. On the basis of the functional classification using Gene Ontology, these proteins were organized into seven different groups according to their general function: (i) web silk proteins-spidroins, (ii) proteins related to the folding/conformation of spidroins, (iii) proteins that protect silk proteins from oxidative stress, (iv) proteins involved in fibrillar preservation of silks in the web, (v) proteins related to ion transport into and out of the glands during silk fiber spinning, (vi) proteins involved in prey capture and pre-digestion, and (vii) housekeeping proteins from all of the glands. Thus, a general mechanism of action for the identified proteins in the silk-producing glands from the Nephila clavipes spider was proposed; the current results also indicate that the webs play an active role in prey capture.

  18. Relationships between supercontraction and mechanical properties of spider silk

    Science.gov (United States)

    Liu, Yi; Shao, Zhengzhong; Vollrath, Fritz

    2005-12-01

    Typical spider dragline silk tends to outperform other natural fibres and most man-made filaments. However, even small changes in spinning conditions can have large effects on the mechanical properties of a silk fibre as well as on its water uptake. Absorbed water leads to significant shrinkage in an unrestrained dragline fibre and reversibly converts the material into a rubber. This process is known as supercontraction and may be a functional adaptation for the silk's role in the spider's web. Supercontraction is thought to be controlled by specific motifs in the silk proteins and to be induced by the entropy-driven recoiling of molecular chains. In analogy, in man-made fibres thermal shrinkage induces changes in mechanical properties attributable to the entropy-driven disorientation of `unfrozen' molecular chains (as in polyethylene terephthalate) or the `broken' intermolecular hydrogen bonds (as in nylons). Here we show for Nephila major-ampullate silk how in a biological fibre the spinning conditions affect the interplay between shrinkage and mechanical characteristics. This interaction reveals design principles linking the exceptional properties of silk to its molecular orientation.

  19. Morphology and Microstructure of Spider Dragline Silk from Araneus Ventricosus

    Institute of Scientific and Technical Information of China (English)

    PAN Zhi-juan; MIURA Mikihiko; MORIKAWA Hideaki; IWASA Masayuki; LIU Min

    2005-01-01

    The spider dragline silk has excellent mechanical properties. The stress- strain curves of dragline silk fibers have intraspecific and intraindividual variability because of the spiders active control during spinning process. To investigate the relationship between the morphology of dragline silk fibers and spinning conditions, four samples were made at the reeling rates of 1mm/s, 20mm/s, 43.5mm/s and 110mm/s from the major ampullate glands of Araneus Ventricosus and the other two of dragline silks were prepared from a crawling or dropping spider. The surface microstructure and nanofibril characteristic were analyzed with atomic force microscopy (AFM). AFM images of 2000nm*2000nm and 500nm*500nm of these samples showed that the spinning condition influenced the surface roughness and fibril size, while AFM images of 200nm*200nm clearly displayed that dragline silk of Araneus Ventricosus included sheet macro-conformation structure. These results can facilitate the further investigation of the spinning mechanism of a spider in order to understand mechanical properties and macromolecular structures of dragline silk.

  20. Silk Fibroin as Edible Coating for Perishable Food Preservation

    Science.gov (United States)

    Marelli, B.; Brenckle, M. A.; Kaplan, D. L.; Omenetto, F. G.

    2016-05-01

    The regeneration of structural biopolymers into micelles or nanoparticles suspended in water has enabled the design of new materials with unique and compelling properties that can serve at the interface between the biotic and the abiotic worlds. In this study, we leveraged silk fibroin quintessential properties (i.e. polymorphism, conformability and hydrophobicity) to design a water-based protein suspension that self-assembles on the surface of food upon dip coating. The water-based post-processing control of the protein polymorphism enables the modulation of the diffusion of gases through the silk fibroin thin membranes (e.g. O2 and CO2 diffusion, water vapour permeability), which is a key parameter to manage food freshness. In particular, an increased beta-sheet content corresponds to a reduction in oxygen diffusion through silk fibroin thin films. By using the dip coating of strawberries and bananas as proof of principle, we have shown that the formation of micrometre-thin silk fibroin membranes around the fruits helps the management of postharvest physiology of the fruits. Thus, silk fibroin coatings enhance fruits’ shelf life at room conditions by reducing cell respiration rate and water evaporation. The water-based processing and edible nature of silk fibroin makes this approach a promising alternative for food preservation with a naturally derived material.

  1. Study on Electrospinning Silk Fibroin Solution

    Institute of Scientific and Technical Information of China (English)

    LI Ni; QIN Xiao-hong; WANG Shan-yuan

    2007-01-01

    A new method of preparing silk fibroin (SF) solution used in the electerospinning was introduced in this paper. According to the method, SF was dissolved in the LiBr/CH2O2 solution directly at room temperature. The method was compared with the traditional method---SF was dissolved in CaCl2 ternary solution. The structure of SF films and the morphology of SF nanofibers were examined by attenuated total reflectance fourier transform intrared (ATR- FrlR) spectroscopy, Scanning electron microscope (SEM) and optical polarizing microscope. The result of this study shows that the new method is a faster, more convenient and high efficient way to get the SF solution and the characteristics of SF fibet made by the new method is much betty.

  2. Naturally derived biofunctional nanofibrous scaffold for skin tissue regeneration.

    Science.gov (United States)

    Suganya, S; Venugopal, J; Ramakrishna, S; Lakshmi, B S; Dev, V R Giri

    2014-07-01

    Significant wound healing activity of Aloe vera (AV) and higher elastic strength of Silk fibroin (SF) along with mammalian cell compatibility makes AV and SF an attractive material for tissue engineering. The purpose of the present work was to combine their unique properties, with the advantage of electrospinning to prepare a hybrid transdermal biomaterial for dermal substitutes. The physico-chemical characterization of the developed scaffold showed finer morphology expressing amino and esteric groups with improved hydrophilic properties and favorable tensile strain of 116% desirable for skin tissue engineering. Their biological response showed favorable fibroblast proliferation compared to control which almost increased linearly by (p<0.01) 34.68% on day 3, (p<0.01) 19.13% on day 6, and (p<0.001) 97.86% on day 9 with higher expression of CMFDA, collagen and F-actin proteins. The obtained results prove that the nanofibrous scaffold with synergistic property of AV and SF would be a potential biomaterial for skin tissue regeneration.

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

    Science.gov (United States)

    Brooks, Amanda E.

    2015-01-01

    Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1) deliver sensitive biologic molecules, (2) promote intimate contact between the mucosa and the drug, and (3) prolong the drug's local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery. PMID:26636069

  4. Tubuliform silk protein: A protein with unique molecular characteristics and mechanical properties in the spider silk fibroin family

    Science.gov (United States)

    Tian, M.; Lewis, R. V.

    2006-02-01

    Orb-web weavers can produce up to six different types of silk and a glue for various functions. Tubuliform silk is unique among them due to its distinct amino acid composition, specific time of production, and atypical mechanical properties. To study the protein composing this silk, tubuliform gland cDNA libraries were constructed from three orb-weaving spiders Argiope aurantia, Araneus gemmoides, and Nephila clavipes. Amino acid composition comparison between the predicted tubuliform silk protein sequence (TuSp1) and the corresponding gland protein confirms that TuSp1 is the major component in tubuliform gland in three spiders. Sequence analysis suggests that TuSp1 shares no significant similarity with its paralogues, while it has conserved sequence motifs with the most primitive spider, Euagrus chisoseus silk protein. The presence of large side-chain amino acids in TuSp1 sequence is consistent with the frustrated β-sheet crystalline structure of tubuliform silk observed in transmission electron microscopy. Repeat unit comparison within species as well as among three spiders exhibits high sequence conservation. Parsimony analysis based on carboxy terminal sequence shows that Argiope and Araneus are more closely related than either is to Nephila which is consistent with phylogenetic analysis based on morphological evidence.

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

    Directory of Open Access Journals (Sweden)

    Amanda E Brooks

    2015-11-01

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

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

    Science.gov (United States)

    Wang, Fei; Zhang, Yu-Qing

    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 (Na2CO3) and neutral soap (NS). After repeatedly boiling silk fibres in an aqueous solution of 0.25% APG three times for 30min 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 Na2CO3. 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. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Multifunctional Silk Nerve Guides for Axon Outgrowth

    Science.gov (United States)

    Tupaj, Marie C.

    Peripheral nerve regeneration is a critical issue as 2.8% of trauma patients present with this type of injury, estimating a total of 200,000 nerve repair procedures yearly in the United States. While the peripheral nervous system exhibits slow regeneration, at a rate of 0.5 mm -- 9 mm/day following trauma, this regenerative ability is only possible under certain conditions. Clinical repairs have changed slightly in the last 30 years and standard methods of treatment include suturing damaged nerve ends, allografting, and autografting, with the autograft the gold standard of these approaches. Unfortunately, the use of autografts requires a second surgery and there is a shortage of nerves available for grafting. Allografts are a second option however allografts have lower success rates and are accompanied by the need of immunosuppressant drugs. Recently there has been a focus on developing nerve guides as an "off the shelf" approach. Although some natural and synthetic guidance channels have been approved by the FDA, these nerve guides are unfunctionalized and repair only short gaps, less than 3 cm in length. The goal of this project was to identify strategies for functionalizing peripheral nerve conduits for the outgrowth of neuron axons in vitro . To accomplish this, two strategies (bioelectrical and biophysical) were indentified for increasing axon outgrowth and promoting axon guidance. Bioelectrical strategies exploited electrical stimulation for increasing neurite outgrowth. Biophysical strategies tested a range of surface topographies for axon guidance. Novel methods were developed for integrating electrical and biophysical strategies into silk films in 2D. Finally, a functionalized nerve conduit system was developed that integrated all strategies for the purpose of attaching, elongating, and guiding nervous tissue in vitro. Future directions of this work include silk conduit translation into a rat sciatic nerve model in vivo for the purpose of repairing long

  8. Silla Art and the Silk Road

    Directory of Open Access Journals (Sweden)

    Kwangshik Choe

    2014-02-01

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

  9. 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.

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

    Science.gov (United States)

    Qi, Yu; Wang, Hui; Wei, Kai; Yang, Ya; Zheng, Ru-Yue; Kim, Ick Soo; Zhang, Ke-Qin

    2017-01-01

    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. PMID:28273799

  11. SERI Surgical Scaffold as an Adjunct for Circumferential Abdominoplasty and Lower Body Lift

    Directory of Open Access Journals (Sweden)

    Andrew Kornstein, MD, FACS

    2014-11-01

    Full Text Available Summary: Patients who have undergone massive weight loss typically have poor-quality skin and fascia and thus are prone to experiencing recurrent skin laxity, bulges, and poor scarring after body contouring efforts, even in the hands of experienced surgeons. Moreover, this challenging patient population often has nutritional deficiencies and concomitant medical problems, which may lead to delayed or suboptimal wound healing. A silk-derived biological scaffold (SBS and its facilitation of autogenous tissue generation may be viewed as a qualitative reinforcement of the superficial fascial system. Therefore, it may help support and stabilize a superficial fascial system that has been weakened by obesity and other factors. When employed in body lifting for patients with massive weight loss who desire long-lasting aesthetic results, it may represent a paradigm shift that has the potential to solve at least some issues that plague this patient population. In the present case of circumferential abdominoplasty and lower body lift, this silk-based bioresorbable scaffold was implanted in one side of the patient’s body but not the other. Throughout the 7-month follow-up period, the patient and her husband (who were blinded as to which side received the SBS and the author consistently observed more favorable results for the SBS side, which included greater postoperative comfort, better shape, higher buttock position, less recurrent laxity, and less descent of the scar.

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

    Science.gov (United States)

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

    2017-06-01

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

  13. Scaffolding students’ assignments

    DEFF Research Database (Denmark)

    Slot, Marie Falkesgaard

    2013-01-01

    This article discusses scaffolding in typical student assignments in mother tongue learning materials in upper secondary education in Denmark and the United Kingdom. It has been determined that assignments do not have sufficient scaffolding end features to help pupils understand concepts and build...... objects. The article presents the results of empirical research on tasks given in Danish and British learning materials. This work is based on a further development of my PhD thesis: “Learning materials in the subject of Danish” (Slot 2010). The main focus is how cognitive models (and subsidiary explicit...... learning goals) can help students structure their argumentative and communica-tive learning processes, and how various multimodal representations can give more open-ended learning possibilities for collaboration. The article presents a short introduction of the skills for 21st century learning and defines...

  14. Clinical Application of a Silk Fibroin Protein Biologic Scaffold for Abdominal Wall Fascial Reinforcement

    Directory of Open Access Journals (Sweden)

    Mark W. Clemens, MD

    2014-11-01

    Conclusions: Postoperative complication rates after 18 months were low, and most surgical complications were managed nonoperatively on an outpatient basis without mesh removal. To our knowledge, this is the only series to report on a long-lasting, transitory SBS for abdominal wall repair and reinforcement. Procedure-specific outcome studies are warranted to delineate optimal patient selection and define potential device characteristic advantages.

  15. Scaffold: Quantum Programming Language

    Science.gov (United States)

    2012-07-24

    included popular classical high-level imperative programming languages (C/C++, Java) [16, 25, 11], hardware description languages ( Verilog ) [13], C-to...hardware languages (System-C) [14] and existing quantum programming languages (QCL) [23]. • Variant of C and Verilog : Scaffold syntax was chosen to be...very similar to C (and to some extent Verilog HDL.) This reflects our belief that expressing computations in terms of familiar iterative and imperative

  16. Synthetic spider silk production on a laboratory scale.

    Science.gov (United States)

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

    2012-07-18

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

  17. Prey type, vibrations and handling interactively influence spider silk expression.

    Science.gov (United States)

    Blamires, S J; Chao, I-C; Tso, I-M

    2010-11-15

    The chemical and mechanical properties of spider major ampullate (MA) silks vary in response to different prey, mostly via differential expression of two genes - MaSp1 and MaSp2 - although the spinning process exerts additional influence over the mechanical properties of silk. The prey cues that initiate differential gene expression are unknown. Prey nutrients, vibratory stimuli and handling have been suggested to be influential. We performed experiments to decouple the vibratory stimuli and handling associated with high and low kinetic energy prey (crickets vs flies) from their prey nutrients to test the relative influence of each as inducers of silk protein expression in the orb web spider Nephila pilipes. We found that the MA silks from spiders feeding on live crickets had greater percentages of glutamine, serine, alanine and glycine than those from spiders feeding on live flies. Proline composition of the silks was unaffected by feeding treatment. Increases in alanine and glycine in the MA silks of the live-cricket-feeding spiders indicate a probable increase in MaSp1 gene expression. The amino acid compositions of N. pilipes feeding on crickets with fly stimuli and N. pilipes feeding on flies with cricket stimuli did not differ from each other or from pre-treatment responses, so these feeding treatments did not induce differential MaSp expression. Our results indicate that cricket vibratory stimuli and handling interact with nutrients to induce N. pilipes to adjust their gene expression to produce webs with mechanical properties appropriate for the retention of this prey. This shows that spiders can genetically alter their silk chemical compositions and, presumably, mechanical properties upon exposure to different prey types. The lack of any change in proline composition with feeding treatment in N. pilipes suggests that the MaSp model determined for Nephila clavipes is not universally applicable to all Nephila.

  18. Nonlinear material behaviour of spider silk yields robust webs.

    Science.gov (United States)

    Cranford, Steven W; Tarakanova, Anna; Pugno, Nicola M; Buehler, Markus J

    2012-02-01

    Natural materials are renowned for exquisite designs that optimize function, as illustrated by the elasticity of blood vessels, the toughness of bone and the protection offered by nacre. Particularly intriguing are spider silks, with studies having explored properties ranging from their protein sequence to the geometry of a web. This material system, highly adapted to meet a spider's many needs, has superior mechanical properties. In spite of much research into the molecular design underpinning the outstanding performance of silk fibres, and into the mechanical characteristics of web-like structures, it remains unknown how the mechanical characteristics of spider silk contribute to the integrity and performance of a spider web. Here we report web deformation experiments and simulations that identify the nonlinear response of silk threads to stress--involving softening at a yield point and substantial stiffening at large strain until failure--as being crucial to localize load-induced deformation and resulting in mechanically robust spider webs. Control simulations confirmed that a nonlinear stress response results in superior resistance to structural defects in the web compared to linear elastic or elastic-plastic (softening) material behaviour. We also show that under distributed loads, such as those exerted by wind, the stiff behaviour of silk under small deformation, before the yield point, is essential in maintaining the web's structural integrity. The superior performance of silk in webs is therefore not due merely to its exceptional ultimate strength and strain, but arises from the nonlinear response of silk threads to strain and their geometrical arrangement in a web.

  19. Synthetic Spider Silk Production on a Laboratory Scale

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2011-06-17

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

  1. Lysine-doped polypyrrole/spider silk protein/poly(l-lactic) acid containing nerve growth factor composite fibers for neural application.

    Science.gov (United States)

    Zhang, Hong; Wang, Kefeng; Xing, Yiming; Yu, Qiaozhen

    2015-11-01

    Lysine-doped polypyrrole (PPy)/regenerated spider silk protein (RSSP)/poly(l-lactic) acid (PLLA)/nerve growth factor (NGF) (L-PRPN) composite scaffold was fabricated by co-axial electrospraying and electrospinning. This L-PRPN composite scaffold had a structure of microfibers with a core-shell structure as the stems and nanofibers as branches. Assessment in vitro demonstrated that the L-PRPN composite micro/nano-fibrous scaffold could maintain integrated structure for at least 4months and the pH value of PBS at about 7.28. It had good biocompatibility and cell adhesion and relatively stable conductivity. PC 12 cells cultured on this scaffold, anisotropic cell-neurite-cell-neurite or neurite-neurite sheets were formed after being cultured for 6days. Evaluations in vivo also showed that L-PRPN composite fibrous conduit was effective at bridging 2.0cm sciatic nerve gap in adult rat within 10months. This conduit and electrical stimulation (ES) through it promoted Schwann cell migration and axonal regrowth. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Privileged scaffolds in lead generation.

    Science.gov (United States)

    Zhao, Hongyu; Dietrich, Justin

    2015-07-01

    The term "privileged scaffold" was coined in 1988 and the strategy was to construct high-affinity ligands from core structures that can bind more than one receptor. Since then, the privileged scaffold-based design has evolved from a stand-alone technology to an integral component of various lead generation platforms. In this review, the authors discuss the applications of the privileged scaffold concept in current lead generation. Specifically, the authors cover the role that privileged scaffolds have played in the mass production of compounds to feed high-throughput screening (HTS) and its role in the design of ligands targeting protein-protein interactions, multiple ligands and warhead-based ligands. It is not the intention of the authors to review all privileged scaffolds known to date. Rather, the aim of this review is to highlight the strategic value of the concept of privileged scaffolds in various contemporary lead generation platforms. The privileged scaffolds as described by the original definition proved abundant in the available chemical space. HTS and other screening methods, in addition to greatly enhanced compound collections, make privileged scaffold-based design less relevant in finding high-affinity ligands than originally envisioned. However, the principle of privileged scaffolds has greatly enhanced and empowered current lead generation technologies.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-15

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

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

    Directory of Open Access Journals (Sweden)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2011-10-01

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

  6. Fabrication of microfibrous and nano-/microfibrous scaffolds: melt and hybrid electrospinning and surface modification of poly(L-lactic acid) with plasticizer.

    Science.gov (United States)

    Yoon, Young Il; Park, Ko Eun; Lee, Seung Jin; Park, Won Ho

    2013-01-01

    Biodegradable poly(L-lactic acid) (PLA) fibrous scaffolds were prepared by electrospinning from a PLA melt containing poly(ethylene glycol) (PEG) as a plasticizer to obtain thinner fibers. The effects of PEG on the melt electrospinning of PLA were examined in terms of the melt viscosity and fiber diameter. Among the parameters, the content of PEG had a more significant effect on the average fiber diameter and its distribution than those of the spinning temperature. Furthermore, nano-/microfibrous silk fibroin (SF)/PLA and PLA/PLA composite scaffolds were fabricated by hybrid electrospinning, which involved a combination of solution electrospinning and melt electrospinning. The SF/PLA (20/80) scaffolds consisted of a randomly oriented structure of PLA microfibers (average fiber diameter = 8.9 µm) and SF nanofibers (average fiber diameter = 820 nm). The PLA nano-/microfiber (20/80) scaffolds were found to have similar pore parameters to the PLA microfiber scaffolds. The PLA scaffolds were treated with plasma in the presence of either oxygen or ammonia gas to modify the surface of the fibers. This approach of controlling the surface properties and diameter of fibers could be useful in the design and tailoring of novel scaffolds for tissue engineering.

  7. Fabrication of Microfibrous and Nano-/Microfibrous Scaffolds: Melt and Hybrid Electrospinning and Surface Modification of Poly(L-lactic acid with Plasticizer

    Directory of Open Access Journals (Sweden)

    Young Il Yoon

    2013-01-01

    Full Text Available Biodegradable poly(L-lactic acid (PLA fibrous scaffolds were prepared by electrospinning from a PLA melt containing poly(ethylene glycol (PEG as a plasticizer to obtain thinner fibers. The effects of PEG on the melt electrospinning of PLA were examined in terms of the melt viscosity and fiber diameter. Among the parameters, the content of PEG had a more significant effect on the average fiber diameter and its distribution than those of the spinning temperature. Furthermore, nano-/microfibrous silk fibroin (SF/PLA and PLA/PLA composite scaffolds were fabricated by hybrid electrospinning, which involved a combination of solution electrospinning and melt electrospinning. The SF/PLA (20/80 scaffolds consisted of a randomly oriented structure of PLA microfibers (average fiber diameter = 8.9 µm and SF nanofibers (average fiber diameter = 820 nm. The PLA nano-/microfiber (20/80 scaffolds were found to have similar pore parameters to the PLA microfiber scaffolds. The PLA scaffolds were treated with plasma in the presence of either oxygen or ammonia gas to modify the surface of the fibers. This approach of controlling the surface properties and diameter of fibers could be useful in the design and tailoring of novel scaffolds for tissue engineering.

  8. Spider web and silk performance landscapes across nutrient space.

    Science.gov (United States)

    Blamires, Sean J; Tseng, Yi-Hsuan; Wu, Chung-Lin; Toft, Søren; Raubenheimer, David; Tso, I-Min

    2016-05-24

    Predators have been shown to alter their foraging as a regulatory response to recent feeding history, but it remains unknown whether trap building predators modulate their traps similarly as a regulatory strategy. Here we fed the orb web spider Nephila pilipes either live crickets, dead crickets with webs stimulated by flies, or dead crickets without web stimulation, over 21 days to enforce spiders to differentially extract nutrients from a single prey source. In addition to the nutrients extracted we measured web architectures, silk tensile properties, silk amino acid compositions, and web tension after each feeding round. We then plotted web and silk "performance landscapes" across nutrient space. The landscapes had multiple peaks and troughs for each web and silk performance parameter. The findings suggest that N. pilipes plastically adjusts the chemical and physical properties of their web and silk in accordance with its nutritional history. Our study expands the application of the geometric framework foraging model to include a type of predatory trap. Whether it can be applied to other predatory traps requires further testing.

  9. Sporicidal/bactericidal textiles via the chlorination of silk.

    Science.gov (United States)

    Dickerson, Matthew B; Lyon, Wanda; Gruner, William E; Mirau, Peter A; Slocik, Joseph M; Naik, Rajesh R

    2012-03-01

    Bacterial spores, such as those of the Bacillus genus, are extremely resilient, being able to germinate into metabolically active cells after withstanding harsh environmental conditions or aggressive chemical treatments. The toughness of the bacterial spore in combination with the use of spores, such as those of Bacillus anthracis, as a biological warfare agent necessitates the development of new antimicrobial textiles. In this work, a route to the production of fabrics that kill bacterial spores and cells within minutes of exposure is described. Utilizing this facile process, unmodified silk cloth is reacted with a diluted bleach solution, rinsed with water, and dried. The chlorination of silk was explored under basic (pH 11) and slightly acidic (pH 5) conditions. Chloramine-silk textiles prepared in acidified bleach solutions were found to have superior breaking strength and higher oxidative Cl contents than those prepared under caustic conditions. Silk cloth chlorinated for ≥1 h at pH 5 was determined to induce >99.99996% reduction in the colony forming units of Escherichia coli, as well as Bacillus thuringiensis Al Hakam (B. anthracis simulant) spores and cells within 10 min of contact. The processing conditions presented for silk fabric in this study are highly expeditionary, allowing for the on-site production of protein-based antimicrobial materials from a variety of agriculturally produced feed-stocks. © 2012 American Chemical Society

  10. Hemocompatibility and cytocompatibility of the hirudin-modified silk fibroin.

    Science.gov (United States)

    Sun, Dan; Hao, Yunxia; Yang, Gaoqiang; Wang, Jiannan

    2015-04-01

    Hirudin (Hir), a thrombin direct inhibitor, was used to modify a polyethylene glycol diglycidyl ether (PEG-DE) crosslinked regenerated silk fibroin (SF) material to improve hemocompatibility. Hemolysis characteristics, platelet adhesion, platelet activity, and plasma recalcification time were investigated using absorption spectrometry, scanning electron microscopy, MTT analysis, and the time counting method. Hirudin could be grafted evenly to the silk fibroin, and the modified material was resistant to hemolysis at ratios of less than 0.5%. Scanning electron microscopy and MTT results showed that platelet adhesion and aggregation activity decreased after modificaton with trace amounts of hirudin, compared with PEG-DE crosslinked and ethanol-treated silk fibroin film. Plasma recalcification of PEG-DE crosslinked silk fibroin film was slower than with ethanol-treated material, and this increased slightly after hirudin modification. Furthermore, L929, HAVSMC, and HUVEC cells adhered to the modified material, grew well, and possessed high proliferation activity on SF/Hir blend films. This study suggests that hirudin could improve the anticoagulation properties of regenerated silk fibroin materials.

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

    Directory of Open Access Journals (Sweden)

    Bo Wei

    2013-01-01

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

  12. Extracted sericin from silk waste for film formation

    Directory of Open Access Journals (Sweden)

    Rungsinee Sothornvit

    2010-03-01

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

  13. A novel property of spider silk: chemical defence against ants.

    Science.gov (United States)

    Zhang, Shichang; Koh, Teck Hui; Seah, Wee Khee; Lai, Yee Hing; Elgar, Mark A; Li, Daiqin

    2012-05-07

    Spider webs are made of silk, the properties of which ensure remarkable efficiency at capturing prey. However, remaining on, or near, the web exposes the resident spiders to many potential predators, such as ants. Surprisingly, ants are rarely reported foraging on the webs of orb-weaving spiders, despite the formidable capacity of ants to subdue prey and repel enemies, the diversity and abundance of orb-web spiders, and the nutritional value of the web and resident spider. We explain this paradox by reporting a novel property of the silk produced by the orb-web spider Nephila antipodiana (Walckenaer). These spiders deposit on the silk a pyrrolidine alkaloid (2-pyrrolidinone) that provides protection from ant invasion. Furthermore, the ontogenetic change in the production of 2-pyrrolidinone suggests that this compound represents an adaptive response to the threat of natural enemies, rather than a simple by-product of silk synthesis: while 2-pyrrolidinone occurs on the silk threads produced by adult and large juvenile spiders, it is absent on threads produced by small juvenile spiders, whose threads are sufficiently thin to be inaccessible to ants.

  14. Reproducing Natural Spider Silks’ Copolymer Behavior in Synthetic Silk Mimics

    Science.gov (United States)

    An, Bo; Jenkins, Janelle E.; Sampath, Sujatha; Holland, Gregory P.; Hinman, Mike; Yarger, Jeffery L.; Lewis, Randolph

    2012-01-01

    Dragline silk from orb-weaving spiders is a copolymer of two large proteins, major ampullate spidroin 1 (MaSp1) and 2 (MaSp2). The ratio of these proteins is known to have a large variation across different species of orb-weaving spiders. NMR results from gland material of two different species of spiders, N. clavipes and A. aurantia, indicates that MaSp1 proteins are more easily formed into β-sheet nanostructures, while MaSp2 proteins form random coil and helical structures. To test if this behavior of natural silk proteins could be reproduced by recombinantly produced spider silk mimic protein, recombinant MaSp1/MaSp2 mixed fibers as well as chimeric silk fibers from MaSp1 and MaSp2 sequences in a single protein were produced based on the variable ratio and conserved motifs of MaSp1 and MaSp2 in native silk fiber. Mechanical properties, solid-state NMR, and XRD results of tested synthetic fibers indicate the differing roles of MaSp1 and MaSp2 in the fiber and verify the importance of postspin stretching treatment in helping the fiber to form the proper spatial structure. PMID:23110450

  15. Peroxidase-catalysed interfacial adhesion of aquatic caddisworm silk.

    Science.gov (United States)

    Wang, Ching-Shuen; Pan, Huaizhong; Weerasekare, G Mahika; Stewart, Russell J

    2015-11-06

    Casemaker caddisfly (Hesperophylax occidentalis) larvae use adhesive silk fibres to construct protective shelters under water. The silk comprises a distinct peripheral coating on a viscoelastic fibre core. Caddisworm silk peroxinectin (csPxt), a haem-peroxidase, was shown to be glycosylated by lectin affinity chromatography and tandem mass spectrometry. Using high-resolution H2O2 and peroxidase-dependent silver ion reduction and nanoparticle deposition, imaged by electron microscopy, csPxt activity was shown to be localized in the peripheral layer of drawn silk fibres. CsPxt catalyses dityrosine cross-linking within the adhesive peripheral layer post-draw, initiated perhaps by H2O2 generated by a silk gland-specific superoxide dismutase 3 (csSOD3) from environmental reactive oxygen species present in natural water. CsSOD3 was also shown to be a glycoprotein and is likely localized in the peripheral layer. Using a synthetic fluorescent phenolic copolymer and confocal microscopy, it was shown that csPxt catalyses oxidative cross-linking to external polyphenolic compounds capable of diffusive interpenetration into the fuzzy peripheral coating, including humic acid, a natural surface-active polyphenol. The results provide evidence of enzyme-mediated covalent cross-linking of a natural bioadhesive to polyphenol conditioned interfaces as a mechanism of permanent adhesion underwater.

  16. Silk-tropoelastin protein films for nerve guidance.

    Science.gov (United States)

    White, James D; Wang, Siran; Weiss, Anthony S; Kaplan, David L

    2015-03-01

    Peripheral nerve regeneration may be enhanced through the use of biodegradable thin film biomaterials as highly tuned inner nerve conduit liners. Dorsal root ganglion neuron and Schwann cell responses were studied on protein films comprising silk fibroin blended with recombinant human tropoelastin protein. Tropoelastin significantly improved neurite extension and enhanced Schwann cell process length and cell area, while the