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Sample records for antheraea pernyi silk

  1. 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.

  2. Interactions between fibroin and sericin proteins from Antheraea pernyi and Bombyx mori silk fibers.

    Science.gov (United States)

    Du, Shan; Zhang, Jin; Zhou, Wei T; Li, Quan X; Greene, George W; Zhu, Hai J; Li, Jing L; Wang, Xun G

    2016-09-15

    Silkworm silk fibers are core-shell composites of fibroin and sericin proteins. Studying the interactions between fibroin and sericin is essential for understanding the properties of these composites. It is observed that compared to the domestic silk cocoon Bombyx mori (B. mori), the adhesion between fibroin and sericin from the wild silk cocoon, Antheraea pernyi (A. pernyi), is significantly stronger with a higher degree of heterogeneity. The adsorption of A. pernyi sericin on its fibroin is almost twice the value for B. mori sericin on fibroin, both showing a monolayer Langmuir adsorption. (1)H NMR and FTIR studies demonstrate on a molecular level the stronger interactions and the more intensive complex formation between A. pernyi fibroin and sericin, facilitated by the hydrogen bonding between glycine and serine. The findings of this study may help the design of composites with superior interfacial adhesion between different components. PMID:27314644

  3. Biomimetic Nucleation of Hydroxyapatite Crystals Mediated by Antheraea pernyi Silk Sericin Promotes Osteogenic Differentiation of Human Bone Marrow Derived Mesenchymal Stem Cells

    OpenAIRE

    Yang, Mingying; Shuai, Yajun; Zhang, Can; Chen, Yuyin; Zhu, Liangjun; Mao, Chuanbin; Ouyang, HongWei

    2014-01-01

    Biomacromolecules have been used as templates to grow hydroxyapatite crystals (HAps) by biomineralization to fabricate mineralized materials for potential application in bone tissue engineering. Silk sericin is a protein with features desirable as a biomaterial, such as increased hydrophilicity and biodegradation. Mineralization of the silk sericin from Antheraea pernyi (A. pernyi) silkworm has rarely been reported. Here, for the first time, nucleation of HAps on A. pernyi silk sericin (AS) w...

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

    Science.gov (United States)

    Luan, Xi-Ying; Wang, Yong; Duan, Xiang; Duan, Qiao-Yan; Li, Ming-Zhong; Lu, Shen-Zhou; Zhang, Huan-Xiang; Zhang, Xue-Guang

    2006-12-01

    Silk fibroin of the silkworm Bombyx mori has been studied extensively, while the research on Antheraea pernyi silk fibroin (A. pernyi SF) in biomaterials is only at an early stage. In this study, the attachment, morphology, growth and phenotype of human bone marrow derived mesenchymal stem cells (hBMSCs) cultured on the regenerated A. pernyi SF films were studied in vitro. The results indicated that the attachment of hBMSCs on the regenerated A. pernyi SF films was almost the same as that on the collagen films. MTT and cell counting analyses demonstrated that the growth of hBMSCs on the regenerated A. pernyi SF films was better than that on controls. Moreover, electron scanning microscopy and fluorescence-activated cell sorting assays showed that the regenerated A. pernyi SF supported hBMSCs growth and functional maintenance compared with the controls. These data suggest that the regenerated A. pernyi SF, like Bombyx mori silk fibroin (B. mori SF) and collagen, can support hBMSCs attachment, growth and phenotypic maintenance, and has better biocompatibilities for hBMSCs in vitro culture. PMID:18458403

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-15

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

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

    International Nuclear Information System (INIS)

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

  7. Antheraea pernyi silk fibroin for targeted gene delivery of VEGF165-Ang-1 with PEI

    International Nuclear Information System (INIS)

    Vascularization is a crucial challenge in tissue engineering. One solution for this problem is to implant scaffolds that contain functional genes that promote vascularization by providing angiogenic growth factors via a gene delivery carrier. Poly(ethylenimine) (PEI) is a gene delivery carrier with high transfection efficiency but with cytotoxicity. To solve this problem, we utilized Antheraea pernyi silk fibroin (ASF), which has favorable cytocompatibility and biodegradability, RGD sequences and a negative charge, in conjunction with PEI, as the delivery vector for vascular endothelial growth factor (VEGF) 165-angiopoietin-1 (Ang-1) dual gene simultaneous expression plasmid, creating an ASF/PEI/pDNA complex. The results suggested that the zeta potential of the ASF/PEI/pDNA complex was significantly lower than that of the PEI/pDNA complex. Decreased nitrogen and increased oxygen on the surface of the complex demonstrated that the ASF had successfully combined with the surface of the PEI/pDNA. Furthermore, the complexes resisted digestion by nucleic acid enzymes and degradation by serum. L929 cells were cultured and transfected in vitro and improved cytotoxicity was found when the cells were transfected with ASF/PEI/pDNA compared with PEI/pDNA. In addition, the transfection efficiency and VEGF secretion increased. In general, this study provides a novel method for decreasing the cytotoxicity of PEI gene delivery vectors and increasing transfection efficiency of angiogenesis-related genes. (paper)

  8. Spermine-modified Antheraea pernyi silk fibroin as a gene delivery carrier

    Directory of Open Access Journals (Sweden)

    Yu Y

    2016-03-01

    Full Text Available Yanni Yu,1 Yongpei Hu,1 Xiufang Li,1 Yu Liu,1 Mingzhong Li,1 Jicheng Yang,2 Weihua Sheng2 1National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, 2Cell and Molecular Biology Institute, College of Medicine, Soochow University, Suzhou, People’s Republic of China Abstract: The development of a novel cationized polymer used as a gene delivery carrier that can conveniently and effectively transfect cells resulting in a stably expressed target gene remains a challenge. Antheraea pernyi silk fibroin (ASF is a cytocompatible and biodegradable natural polymer, and it possesses Arg–Gly–Asp sequences but a negative charge. In order to render ASF amenable to packaging plasmid DNA (pDNA, spermine was used to modify ASF to synthesize cationized ASF (CASF, which was used as a gene delivery carrier. CASF was characterized using trinitrobenzene sulfonic acid assay, the zeta potential determination, and a Fourier transform infrared analysis, and the results of these characterizations indicated that the –NH2 in spermine effectively reacts with the –COOH in the side chains of ASF. Spermine grafted to the side chains of ASF resulted in the conversion of the negative charge of ASF to a positive charge. CASF packaged pDNA and formed CASF/pDNA complexes, which exhibited spherical morphology with average particle sizes of 215–281 nm and zeta potential of approximately +3.0 mV to +3.2 mV. The results of the MTT assay, confocal laser scanning microscopy, and flow cytometry analysis in a human endothelial cell line revealed that CASF/pDNA complexes exhibited lower cytotoxicity and higher transfection efficiency compared to the pDNA complexes of polyethyleneimine. These results indicate that our synthesized CASF, a cationized polymer, is a potential gene delivery carrier with the advantages of biodegradability and low cytotoxicity. Keywords: silk fibroin, spermine, cationized polymer, gene delivery

  9. Assessment of freestanding membranes prepared from Antheraea pernyi silk fibroin as a potential vehicle for corneal epithelial cell transplantation

    International Nuclear Information System (INIS)

    Freestanding membranes created from Bombyx mori silk fibroin (BMSF) offer a potential vehicle for corneal cell transplantation since they are transparent and support the growth of human corneal epithelial (HCE) cells. Fibroin derived from the wild silkworm Antheraea pernyi (APSF) might provide a superior material by virtue of containing putative cell-attachment sites that are absent from BMSF. Thus we have investigated the feasibility of producing transparent, freestanding membranes from APSF and have analysed the behaviour of HCE cells on this material. No significant differences in cell numbers or phenotype were observed in short term HCE cell cultures established on either fibroin. Production of transparent freestanding APSF membranes, however, proved to be problematic as cast solutions of APSF were more prone to becoming opaque, displayed significantly lower permeability and were more brittle than BMSF-membranes. Cultures of HCE cells established on either membrane developed a normal stratified morphology with cytokeratin pair 3/12 being immuno-localized to the superficial layers. We conclude that while it is feasible to produce transparent freestanding membranes from APSF, the technical difficulties associated with this biomaterial, along with an absence of enhanced cell growth, currently favour the continued development of BMSF as a preferred vehicle for corneal cell transplantation. Nevertheless, it remains possible that refinement of techniques for processing APSF might yet lead to improvements in the handling properties and performance of this material. (paper)

  10. Morphological and molecular characterization of Nosema pernyi, a microsporidian parasite in Antheraea pernyi.

    Science.gov (United States)

    Wang, Yong; Liu, Wei; Jiang, Yiren; Huang, Ling; Irfan, Muhammad; Shi, Shenglin; Yang, Ruisheng; Qin, Li

    2015-09-01

    Nosema pernyi is a lethal pathogen that causes microsporidiosis in the Chinese oak silkworm, Antheraea pernyi. In this study, we presented its morphological and some molecular characteristics. The mature spores were measured to be 4.36 × 1.49 μm. The spore wall consisted of an electron-dense exospore (EX) and electron-lucent endospore (EN) layer. The polar filament (PF) was isofilar with 10-12 coils that were frequently arranged in a single row. Investigation results indicated that N. pernyi can infect the gut wall, silk glands, and other tissues. A full-length SMART cDNA library of N. pernyi was constructed, and then 824 expressed sequence tags (ESTs) were sequenced. Ninety unigenes, out of 197 assembled unigenes, showed significant homology to known genes of Nosema ceranae, Nosema bombycis, Encephalitozoon cuniculi, and other microsporidian species. Based on the nucleotide sequence of the α- and β-tubulin genes and amino acid sequence of actin gene, phylogenetic trees analysis showed that N. pernyi was closely related to Nosema philosamiae and Nosema antheraeae. It was correctly assigned to the Nosema group. PMID:26044882

  11. Antheraea pernyi Silk Fibroin-Coated PEI/DNA Complexes for Targeted Gene Delivery in HEK 293 and HCT 116 Cells

    Directory of Open Access Journals (Sweden)

    Yu Liu

    2014-04-01

    Full Text Available Polyethylenimine (PEI has attracted much attention as a DNA condenser, but its toxicity and non-specific targeting limit its potential. To overcome these limitations, Antheraea pernyi silk fibroin (ASF, a natural protein rich in arginyl-glycyl-aspartic acid (RGD peptides that contains negative surface charges in a neutral aqueous solution, was used to coat PEI/DNA complexes to form ASF/PEI/DNA ternary complexes. Coating these complexes with ASF caused fewer surface charges and greater size compared with the PEI/DNA complexes alone. In vitro transfection studies revealed that incorporation of ASF led to greater transfection efficiencies in both HEK (human embryonic kidney 293 and HCT (human colorectal carcinoma 116 cells, albeit with less electrostatic binding affinity for the cells. Moreover, the transfection efficiency in the HCT 116 cells was higher than that in the HEK 293 cells under the same conditions, which may be due to the target bonding affinity of the RGD peptides in ASF for integrins on the HCT 116 cell surface. This result indicated that the RGD binding affinity in ASF for integrins can enhance the specific targeting affinity to compensate for the reduction in electrostatic binding between ASF-coated PEI carriers and cells. Cell viability measurements showed higher cell viability after transfection of ASF/PEI/DNA ternary complexes than after transfection of PEI/DNA binary complexes alone. Lactate dehydrogenase (LDH release studies further confirmed the improvement in the targeting effect of ASF/PEI/DNA ternary complexes to cells. These results suggest that ASF-coated PEI is a preferred transfection reagent and useful for improving both the transfection efficiency and cell viability of PEI-based nonviral vectors.

  12. Variation and Characterization Analysis of Partial Fragment of Fibroin Gene From Silkworm, Antheraea pernyi

    Institute of Scientific and Technical Information of China (English)

    Li Wenli(李文利); Jin Liji; An Lijia

    2003-01-01

    A 1.4Kb DNA fragment containing 3' flanking sequence of fibroin gene of silkworm, Antheraea pernyi, was obtained from the silk gland's mRNA of 5th larva. Analysis of this sequence with another A.pernyi fibroin protein (accession No. D83241) revealed that it consists of a completely open reading frame (ORF), which includes 14 polyalanine-containing units (motifs) and 100bp 3'-UTR. The sequence of the predicted amino acid reveals the highest level of overall identity (90%) with D83241. It was found that it loses a repeat region at the upstream of TAA codon and some mutations. A putative polyadenylation signal AATAAA tail was found in position 1300, which follows the termination codon.

  13. Nutrigenomics in Arma chinensis: transcriptome analysis of Arma chinensis fed on artificial diet and Chinese oak silk moth Antheraea pernyi pupae.

    Directory of Open Access Journals (Sweden)

    Deyu Zou

    Full Text Available BACKGROUND: The insect predator, Arma chinensis, is capable of effectively controlling many pests, such as Colorado potato beetle, cotton bollworm, and mirid bugs. Our previous study demonstrated several life history parameters were diminished for A. chinensis reared on an artificial diet compared to a natural food source like the Chinese oak silk moth pupae. The molecular mechanisms underlying the nutritive impact of the artificial diet on A. chinensis health are unclear. So we utilized transcriptome information to better understand the impact of the artificial diet on A. chinensis at the molecular level. METHODOLOGY/PRINCIPAL FINDINGS: Illumina HiSeq2000 was used to sequence 4.79 and 4.70 Gb of the transcriptome from pupae-fed and artificial diet-fed A. chinensis libraries, respectively, and a de novo transcriptome assembly was performed (Trinity short read assembler. This resulted in 112,029 and 98,724 contigs, clustered into 54,083 and 54,169 unigenes for pupae-fed and diet-fed A. chinensis, respectively. Unigenes from each sample's assembly underwent sequence splicing and redundancy removal to acquire non-redundant unigenes. We obtained 55,189 unigenes of A. chinensis, including 12,046 distinct clusters and 43,143 distinct singletons. Unigene sequences were aligned by BLASTx to nr, Swiss-Prot, KEGG and COG (E-value <10(-5, and further aligned by BLASTn to nt (E-value <10(-5, retrieving proteins of highest sequence similarity with the given unigenes along with their protein functional annotations. Totally, 22,964, 7,898, 18,069, 15,416, 8,066 and 5,341 unigenes were annotated in nr, nt, Swiss-Prot, KEGG, COG and GO, respectively. We compared gene expression variations and found thousands of genes were differentially expressed between pupae-fed and diet-fed A. chinensis. CONCLUSIONS/SIGNIFICANCE: Our study provides abundant genomic data and offers comprehensive sequence information for studying A. chinensis. Additionally, the physiological

  14. The expression of GFP under the control of fibroin promotor in primary ovarian cells of Antheraea pernyi

    Indian Academy of Sciences (India)

    Wenli Li; Liji Jin; Pengcheng Bu; Lijia An

    2003-12-01

    The fibroin promoter can stably express foreign gene in lepidopteran cells. Total RNA was extracted from the gland of silkworm, Antheraea pernyi and the transcription initiation site of fibroin gene of A. pernyi was identified by RNA ligase mediated rapid amplification of cDNA ends (RLM-RACE). The expression vector (pGFP-N2/Fib) was constructed by use of replacing the CMV promoter with the fibroin promoter. The results of visual screening under a fluorescent inverted microscope and Western blot analysis indicated that the GFP gene was expressed in the primary cells of ovary origins from A. pernyi.

  15. The complete mitochondrial genome of Antheraea pernyi strain 731 (Lepidoptera: Saturniidae).

    Science.gov (United States)

    Zhang, Yongliang; Wu, An-Quan

    2016-07-01

    In this study, the complete mitochondrial genome of Antheraea pernyi strain 731 (Lepidoptera: Saturniidae) is determined for the first time. It is a circular molecule of 15,570 bp in length, with 37 typical coding genes and one non-coding A T-rich region. Its gene order and content are identical to the common type found in most insect mitogenomes. All protein-coding genes (PCGs) start with a typical ATN initiation codon, except for the cox1 gene, which begins with TTAG codon. Nine genes used standard complete termination codon TAA, whereas the cox1, cox2, nad3, and nad5 genes end with single T. All tRNAs display typical secondary cloverleaf structures as those of other insects. Additionally, the non-coding AT-rich region is 553 bp long, located between rrnS and trnM genes. It contains some structures of repeated motifs and microsatellite-like elements characteristic of the other lepidopterons. Phylogenetic analysis showed that the Antheraea pernyi 731 was close to Saturniidae. PMID:25939049

  16. Diapause-associated protein3 functions as Cu/Zn superoxide dismutase in the Chinese oak silkworm (Antheraea pernyi.

    Directory of Open Access Journals (Sweden)

    Zhenle Bi

    Full Text Available To better understand the molecular mechanism underlying of diapause in Antheraea pernyi (A. pernyi, we cloned a novel diapause-associated protein 3 (DAP3 gene from A. pernyi by reverse transcription-polymerase chain reaction (RT-PCR and studied the biological functions. Sequence analysis revealed that this gene encodes 171 amino acids and has a conserved domain of Copper/Zinc superoxide dismutase (Cu/Zn-SOD. Western blot and qRT-PCR results showed that DAP3 was mainly expressed in the pupal stage, and gradually decreased as diapause development. DAP3 was also expressed in 1st and 5th instar larvae of A. pernyi. In tissues of 5th instar larvae of A. pernyi, DAP3 was mainly expressed in the epidermis, followed by the head, hemolymph and fat body. To identify the SOD activity of DAP3, we constructed a prokaryotic expression vector by inserting the coding region sequence into plasmid pET-28a (+ and obtained the purified rHIS-DAP3 fusion protein by Ni-NTA affinitive column. Importantly, we found the SOD activity of DAP3 fusion protein was approximately 0.6674 U/µg. To further confirm the SOD activity of DAP3 in vivo, we induced the oxidative stress model of pupae by UV irradiation. The results showed that both the mRNA and protein level of DAP3 significantly increased by UV irradiation. Furthermore, the SOD activity of the total lysate of pupae increased significantly at 10 min post UV irradiation and transiently returned to normal level afterwards. These results suggested that DAP3 might be a novel protein with SOD activity getting involved in regulation of diapause in A. pernyi.

  17. Cloning and sequence analysis of the Antheraea pernyi nucleopolyhedrovirus gp64 gene

    Indian Academy of Sciences (India)

    Wenbing Wang; Shanying Zhu; Liqun Wang; Feng Yu; Weide Shen

    2005-12-01

    Frequent outbreaks of the purulence disease of Chinese oak silkworm are reported in Middle and Northeast China. The disease is produced by the pathogen Antheraea pernyi nucleopolyhedrovirus (AnpeNPV). To obtain molecular information of the virus, the polyhedra of AnpeNPV were purified and characterized. The genomic DNA of AnpeNPV was extracted and digested with HindIII. The genome size of AnpeNPV is estimated at 128 kb. Based on the analysis of DNA fragments digested with HindIII, 23 fragments were bigger than 564 bp. A genomic library was generated using HindIII and the positive clones were sequenced and analysed. The gp64 gene, encoding the baculovirus envelope protein GP64, was found in an insert. The nucleotide sequence analysis indicated that the AnpeNPV gp64 gene consists of a 1530 nucleotide open reading frame (ORF), encoding a protein of 509 amino acids. Of the eight gp64 homologues, the AnpeNPV gp64 ORF shared the most sequence similarity with the gp64 gene of Anticarsia gemmatalis NPV, but not Bombyx mori NPV. The upstream region of the AnpeNPV gp64 ORF encoded the conserved transcriptional elements for early and late stage of the viral infection cycle. These results indicated that AnpeNPV belongs to group I NPV and was far removed in molecular phylogeny from the BmNPV.

  18. The complete mitochondrial genome of the Chinese oak silkmoth, Antheraea pernyi (Lepidoptera: Saturniidae)

    Institute of Scientific and Technical Information of China (English)

    Yanqun Liu; Yuping Li; Minhui Pan; Fangyin Dai; Xuwei Zhu; Cheng Lu; Zhonghuai Xiang

    2008-01-01

    We determined the complete nucleotide sequence of the mitogenome from Chinese oak silkmoth, Antheraea pernyi (Lepidoptera: Saturniidae). The 15,566 bp circular genome contains a typical gene organization and order for lepidopteran mitogenomes.The mitogenome contains the lowest A+T content (80.16%)among the lnown lepidopteran mitogenome sequences.An unusual feature is the occurrence of more Ts than As,with a slightly negative AT skewness(-0.021),in the composition of the major genome strand.All protein-coding genes are initiated by ATN codons,except for cytochrome oxidase subunit I,which is proposed by the TTAG sequence as observed in other lepidopterans.All transfer RNAs(tRNAs)have a typical clover-leaf structure of mitochondrial tRNA,except for tRNASer(AGN),the DHU arm of which could not form a stable stem-loop structure.Two aligned sequence blocks with a length of more than 50 bp and 90% of the sequence identity were identified in the A+T-rich region of the Saturniidae and Bombycoidae species.

  19. 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

  20. Analysis of Bacterial Community and Screening and Identification of Enzyme-Producing Bacteria in Intestine of Antheraea pernyi%柞蚕肠道菌群分析及产酶菌的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    邹昌瑞; 魏国清; 刘朝良; 朱保建; 王在贵; 杨文静

    2011-01-01

    [目的]研究柞蚕肠道菌群结构及产酶菌,探寻具有新的生理功能的微生物,用于研制微生态制剂,以提高柞蚕生产的叶丝转化率及抗病能力.[方法]采用培养法分离柞树叶饲喂的5龄柞蚕幼虫肠道细菌,通过生理生化特性结合16S rDNA系统发育分析,对其肠道细菌群落类型进行鉴定,采用筛选培养基筛选产纤维素酶、蛋白酶、脂肪酶的菌株.[结果]获得的柞蚕肠道菌有芽孢杆菌、葡萄球菌、肠杆菌,其中以芽孢杆菌为主要菌群.芽孢杆菌是肠道菌中产纤维素酶、蛋白酶的主要菌群;葡萄球菌产蛋白酶能力较弱;肠杆菌不产酶.[结论]柞蚕肠道菌与家蚕肠道菌群结构相似,筛选出的产酶菌活性较高,可以制备微生态制剂用于蚕业生产.%[Objective] The objective of this study is to isolate and identify bacterial community and enzyme-producing bacteria in intestine of Antheraea pernyi larvae and to develop microecological agents for increasing leaf-silk conversation rate and disease resistance. [ Method ] Bacteria were isolated from intestine of fifth instars Antheraea pernyi larvae reared on oak leaves by isolated culture. Intestinal bacterial community was identified according to physiological and biochemical characteristics and phylogenetic analysis based on 16S rDNA sequences. Cellulase, protease, lipase-producing strains were screened on selective medium. [Result] The intestinal bacteria isolated from Antheraea pernyi larvae belong to Bacillus, Staphylococcus and Enterobacter. Among them, Bacillus is the main bacteria and the main enzyme-producing bacteria which could produce cellulase and protease, Staphylococcus could produce protease weakly, Enterobacter couldn't produce enzyme. [Conclusion] Intestinal bacteria community of Antheraea pernyi was similar to that of Bombyx mori, which could be developed as microecological agents in sericulture for the enzyme-producing strains exhibiting high activity.

  1. Sericin Composition in the Silk of Antheraea yamamai.

    Science.gov (United States)

    Zurovec, Michal; Yonemura, Naoyuki; Kludkiewicz, Barbara; Sehnal, František; Kodrik, Dalibor; Vieira, Ligia Cota; Kucerova, Lucie; Strnad, Hynek; Konik, Peter; Sehadova, Hana

    2016-05-01

    The silks produced by caterpillars consist of fibroin proteins that form two core filaments, and sericin proteins that seal filaments into a fiber and conglutinate fibers in the cocoon. Sericin genes are well-known in Bombyx mori (Bombycidae) but have received little attention in other insects. This paper shows that Antheraea yamamai (Saturniidae) contains five sericin genes very different from the three sericin genes of B. mori. In spite of differences, all known sericins are characterized by short exons 1 and 2 (out of 3-12 exons), expression in the middle silk gland section, presence of repeats with high contents of Ser and charged amino acid residues, and secretion as a sticky silk component soluble in hot water. The B. mori sericins represent tentative phylogenetic lineages (I) BmSer1 and orthologs in Saturniidae, (II) BmSer2, and (III) BmSer3 and related sericins of Saturniidae and of the pyralid Galleria mellonella. The lineage (IV) seems to be limited to Saturniidae. Concerted evolution of the sericin genes was apparently associated with gene amplifications as well as gene loses. Differences in the silk fiber morphology indicate that the cocktail of sericins linking the filaments and coating the fiber is modified during spinning. Silks are composite biomaterials of conserved function in spite of great diversity of their composition. PMID:27049111

  2. Supplementation of an Artificial Medium for the Parasitoid Exorista larvarum (Diptera: Tachnidae) With Hemolymph of Hermetia illucens (Diptera: Stratiomyidae) or Antheraea pernyi (Lepidoptera: Saturniidae).

    Science.gov (United States)

    Dindo, Maria Luisa; Vandicke, Jonas; Marchetti, Elisa; Spranghers, Thomas; Bonte, Jochem; De Clercq, Patrick

    2016-04-01

    The effect of supplementing hemolymph of the black soldier fly, Hermetia illucens (L.), or the Chinese oak silkworm, Antheraea pernyi (Guérin-Méneville), to a basic insect-free artificial medium for the tachinid Exorista larvarum (L.) was investigated. The supplementation (20% w/w) was based on the assumption that insect additives may optimize the media for this parasitoid. Egg hatch, pupal and adult yields, and sex ratio did not differ among the enriched and basic media. Preimaginal development was faster on both hemolymph-enriched media than on the basic medium. Despite the shorter development on the medium supplemented with H. illucens hemolymph than on the basic medium, on the two media puparium weights were comparable. The female flies reared on the medium enriched with H. illucens hemolymph did not lay more eggs, but the latter yielded significantly more puparia compared with the control females. Conversely, the medium enriched with A. pernyi hemolymph yielded lower female puparium weights than the basic medium and produced only one ovipositing female out of the five obtained female adults. These results indicate that the in vitro development of E. larvarum improved when the basic artificial medium was enriched with H. illucens hemolymph, whereas the supplementation with A. pernyi hemolymph negatively affected the quality of the in vitro-reared females. PMID:26921223

  3. Purification and characterization of a 1,3-β-D-glucan recognition protein from Antheraea pernyi larve that is regulated after a specific immune challenge

    Directory of Open Access Journals (Sweden)

    Ma Youlei

    2013-05-01

    Full Text Available Pattern recognition receptors are known to participate in theactivation of Prophenoloxidase system. In this study, a1,3-β-D-glucan recognition protein was detected for the firsttime in Antheraea pernyi larvae (Ap-βGRP. Ap-βGRP waspurified to 99.9% homogeneity from the hemolymph usingtraditional chromatographic methods. Ap-βGRP specificallybind 1,3-β-D-glucan and yeast, but not E. coli or M. luteus.The 1,3-β-D-glucan dependent phenoloxidase (PO activity ofthe hemolymph inhibited by anti-Ap-βGRP antibody could berecovered by addition of purified Ap-βGRP. These resultsdemonstrate that Ap-βGRP acts as a biosensor of 1,3-β-Dglucanto trigger the Prophenoloxidase system. A trace mountof 1,3-β-D-glucan or Ap-βGRP alone was unable to trigger theproPO system, but they both did. Ap-βGRP was specificallydegraded following the activation of proPO with 1,3-β-Dglucan.These results indicate the variation in the amount ofAp-βGRP after specific immune challenge in A. pernyihemolymph is an important regulation mechanism to immuneresponse. [BMB Reports 2013; 46(5: 264-269

  4. The Application of Artificial Insemination Technology in Distant Hybridization Between Antheraea pernyi and Dictyoploca japonica%人工授精技术在柞蚕与栗蚕远缘杂交中的应用

    Institute of Scientific and Technical Information of China (English)

    宿桂梅; 刘凤云; 戚俐; 徐亮; 孟宪民; 焦阳

    2011-01-01

    研究柞蚕(Antheraea pernyi)与栗蚕(Dictyoploca japonica)的人工授精技术,并应用于柞蚕与栗蚕的种间杂交试验,为利用远缘杂交改良柞蚕的经济性状提供试验技术.从种内交配40~60min的柞蚕雌蛾交配囊中采集精子细胞用于对柞蚕处女蛾的人工授精,其受精蛾率为61.5%,受精卵率为70.5%,孵化卵率为60.8%.栗蚕精子可在种内交配40~75 min的雌蛾交配囊中采集.利用单蛾精液授精和单蛾与多蛾精液互补授精的方法,分别获得了栗蚕♀×柞蚕♂的越冬卵和蚁蚕及柞蚕♀×栗蚕♂的活胚胎.试验结果表明,采用初步建立的人工授精技术,可以进行柞蚕与栗蚕的远缘杂交.%In present study, the artificial insemination technique for tussah silkworm (Antheraea pernyi) and camphor silkworm (Dictyoploca japonica) was studied and applied in interspecific hybridization between tussah silkworm and camphor silkworm to improve economic traits of tussah silkworm through distant hybridization. Sperm cells of tussah silkworm were collected from copulatory pouches of female tussah silkworm moths after 40 to 60 min of intraspecific mating and were used to artificially inseminate the unmated tussah silkworm moths, which could lead to 61.5% of moths fertilized, 70.5% of eggs fertilized, and 60.8% of eggs hatched. Sperm cells of camphor silkworm could be collected from copulatory pouches of female camphor silkworm moths after 40 to 75 min of intraspecific mating. By means of insemination with single moth's sperm and complementary insemination with single and multiple moths' sperm, hibernating eggs of camphor silkworm ♀ xtussah silkworm ♂ and live embryos of tussah silkworm ♀ xcamphor silkworm ♂ were obtained respectively. This result indicated that a distant hybridization between Antheraea pernyi and Dictyoploca japonica can be conducted based on the newly established artificial insemination technology.

  5. Enhanced CD3+/CD4+T Cell Activities and Modulation of Th1/Th2 Lineage Development in Irradiated Rats Due to Treatment with the Male Zooid of Antheraea Pernyi Extracts

    Institute of Scientific and Technical Information of China (English)

    ZHAO Bin; ZHANG Hong-Yu; ZHAO Wen-Hua; ZHANG Bo; ZONG Min; TANG Ji-dong; YU Jin-ming; LI Sheng

    2008-01-01

    Objective:Cancer patients undergoing large dose radiotherapy exhibit multifaceted defects in their immune capacity that are likely to contribute to an increased susceptibility to infections and disease progression.The immune impairment may also constitute a barrier to effective immunotherapeutic interventions.Here.we evaluate whether supplementation with the male zooid of Antheraea pernyi extracts could enhance immune function in irradiated rats. Methods:Fifty male Wistar rats were randomly divided into a control group,a simple radiation group and a treatment group.The mice in the simple irradiation and treatment groups were given whole-chest irradiation with 6Gy.In the treatment group,the male zooid of Antheraea pernyi extracts was gavaged at the doses of 16.53mg/kg(1arge dose group),2.62mg/kg(medium dose group),and 0.564mg/kg(small dose group)once a day for 14 days.The thymus and spleen indices were calculated.T cell subsets in peripheral blood were determined by flow cytometry and the expressions of IL-2,IFN-γ,IL-4 and IL-10 in sera were determined by ELISA on the 15th day. Results:The thymus index and spleen index of the high dose treatment group were statistically lower than that of the control group and higher than that of the radiation group(P<0.01).CD3+and CD4+ T cells in the peripheral blood were increased in the high dose treatment group and decreased in the radiation group(P<0.01).Expression of IL-2 and INF-γ in the radiation group was lower than that in control,and significantly increased during therapy.The production of IL-4 and IL-10 could be induced by radiation and was inhibited in the high dose treatment group(P<0.01). Conclusion:Our data indicate that the male zooid of Antheraea pernyi extracts may be administrated to improve immune function in irradiated rats and reverse the radial immune inhibition of rats by stimulating the proliferation of Th cells and inducing the differentiation of Th2 to Th1.

  6. Influence of Hybridization on the Traits of Silk Production and Filament Denier in Indian Tropical Tasar Silk Insect, Antheraea mylitta Drury

    Directory of Open Access Journals (Sweden)

    A.K. Srivastava

    2010-01-01

    Full Text Available The aim of the present study is to explore hybridization influence to achieve the potential of silk yield and quality in commercial tasarculture, as against the current status of applying only a few wild and semi-domesticated ecoraces of Antheraea mylitta D to produce raw silk during commercial crop rearing season (September-December. The four F1 hybrid combinations generated using Daba, Jata and Raily tasar ecoraces of seed crop rearing season (July-August were evaluated during commercial crop season of 2007 and 2008 for the influence of hybridization as positive heterosis in the traits of economically important silk productivity and filament denier. The F1 hybrid, Daba x Jata has recorded positive heterosis in single shell weight (+25.6%, total silk yield (+79.0% and silk filament length (+68.1%, but for silk filament of high denier (11.98 d followed by its reciprocal hybrid, JataxDaba in shell weight (+18.8%, silk yield (+68.1%, filament length (+63.8% and filament of highest denier (12.32 d. Though, the RailyxDaba hybrid could show highest heterosis in shell weight (2.47 g with filament of least denier (10.86 d, the improvement in filament length was marginal (+44.7% and heterosis in silk yield was negative (-47.0%, while the performance of DabaxRaily hybrid was least among the hybrids. The study infers hybridization influence on silk related traits at F1 level as positive heterosis and the application feasibility of DabaxJata and JataxDaba hybrids during commercial crop rearing season for higher silk productivity with silk filament denier at least better than one of the parents of F1 hybrid combination.

  7. Comparison of the in vitro and in vivo degradations of silk fibroin scaffolds from mulberry and nonmulberry silkworms

    International Nuclear Information System (INIS)

    Degradation behavior is very important in the field of silk-based biomaterials. Mulberry and nonmulberry silk fibroins are structurally and functionally distinguishable; however, no studies have examined the differences in the degradation behaviors of silk materials from various silkworm species. In this study, Ca(NO3)2 was used as a uniform solvent to obtain regenerated mulberry and nonmulberry (Antheraea pernyi and Antheraea yamamai) silk fibroin (SF) solutions, and the degradation behaviors of various SF scaffolds were examined. In vitro and in vivo results demonstrated that regenerated mulberry SF scaffolds exhibited significantly higher mass loss and free amino acid content release than did nonmulberry SF scaffolds. The differences in the primary structures and condensed structures between mulberry and nonmulberry SF contributed to the significant difference in degradation rates, in which the characteristic (–Ala–)n repeats, compact crystal structure and high α-helix and β-sheet contents make nonmulberry SF more resistant than mulberry SF to enzymatic degradation. Moreover, the Antheraea pernyi and Antheraea yamamai SFs possess similar primary structures and condensed structures, although a slight difference in degradation was observed; this difference might depend on the differences in molecular weight following the regeneration process. The results indicate that the original sources of SF significantly influence the degradation rates of SF-based materials; therefore, the original sources of SF should be fully considered for preparing tissue engineering scaffolds with matched degradation rates. (paper)

  8. A novel pattern recognition protein of the Chinese oak silkmoth, Antheraea pernyi, is involved in the pro-PO activating system

    Directory of Open Access Journals (Sweden)

    Wu Chunfu

    2013-07-01

    Full Text Available In this paper, we firstly reported a C-type lectin cDNA clone of1029 bps from the larvae of A. Pernyi (Ap-CTL using PCR andRACE techniques. The full-length cDNA contains an openreading frame encoding 308 amino acid residues which hastwo different carbohydrate-recognition domains (CRDs arrangedin tandem. To investigate the biological activities in theinnate immunity, recombinant Ap-CTL was expressed in E. coliwith a 6-histidine at the amino-terminus (Ap-rCTL. Besidesacted as a broad-spectrum recognition protein binding to awide range of PAMPs and microorganisms, Ap-rCTL also hadthe ability to recognize and trigger the agglutination of bacteriaand fungi. In the proPO activation assay, Ap-rCTL specificallyrestored the PO activity of hemolymph blocked by anti-Ap-rCTL antibody in the presence of different PAMPs ormicroorganisms. In summary, Ap-rCTL plays an important rolein insect innate immunity as an pattern recognition protein.[BMB Reports 2013; 46(7: 358-363

  9. Glass transitions in native silk fibres studied by dynamic mechanical thermal analysis.

    Science.gov (United States)

    Guan, Juan; Wang, Yu; Mortimer, Beth; Holland, Chris; Shao, Zhengzhong; Porter, David; Vollrath, Fritz

    2016-07-01

    Silks are a family of semi-crystalline structural materials, spun naturally by insects, spiders and even crustaceans. Compared to the characteristic β-sheet crystalline structure in silks, the non-crystalline structure and its composition deserves more attention as it is equally critical to the filaments' high toughness and strength. Here we further unravel the structure-property relationship in silks using Dynamic Mechanical Thermal Analysis (DMTA). This technique allows us to examine the most important structural relaxation event of the disordered structure the disordered structure, the glass transition (GT), in native silk fibres of the lepidopteran Bombyx mori and Antheraea pernyi and the spider Nephila edulis. The measured glass transition temperature Tg, loss tangent tan δ and dynamic storage modulus are quantitatively modelled based on Group Interaction Modelling (GIM). The "variability" issue in native silks can be conveniently explained by the different degrees of structural disorder as revealed by DMTA. The new insights will facilitate a more comprehensive understanding of the structure-property relations for a wide range of biopolymers. PMID:27320178

  10. Non-Mulberry and Mulberry Silk Protein Sericins as Potential Media Supplement for Animal Cell Culture

    OpenAIRE

    Sahu, Neety; Pal, Shilpa; Sapru, Sunaina; Kundu, Joydip; Talukdar, Sarmistha; Singh, N. Ibotambi; Yao, Juming; Kundu, Subhas C.

    2016-01-01

    Silk protein sericins, in the recent years, find application in cosmetics and pharmaceuticals and as biomaterials. We investigate the potential of sericin, extracted from both mulberry Bombyx mori and different non-mulberry sources, namely, tropical tasar, Antheraea mylitta; muga, Antheraea assama; and eri, Samia ricini, as growth supplement in serum-free culture medium. Sericin supplemented media containing different concentrations of sericins from the different species are examined for atta...

  11. Identification of RAPD and SCAR markers associated with yield traits in the Indian tropical tasar silkworm Antheraea mylitta drury

    OpenAIRE

    Dutta, Suhrid R.; Kar, Prasanta K.; Ashok K. Srivastava; Sinha, Manoj K.; Jai Shankar; Ghosh, Ananta K.

    2012-01-01

    The tropical tasar silkworm, Antheraea mylitta, is a semi-domesticated vanya silk-producing insect of high economic importance. To date, no molecular marker associated with cocoon and shell weights has been identified in this species. In this report, we identified a randomly amplified polymorphic DNA (RAPD) marker and examined its inheritance, and also developed a stable diagnostic sequence-characterized amplified region (SCAR) marker. Silkworms were divided into groups with high (HCSW) and l...

  12. Expression of the Japanese oak silkworm Antheraea yamamai fibroin gene in the domesticated silkworm Bombyx mori

    Institute of Scientific and Technical Information of China (English)

    Isao Kobayashi; Katsura Kojima; Hideki Sezutsu; Keiro Uchino; Toshiki Tamura

    2009-01-01

    To understand the evolutionary conservation of the gene expression mechanism and secretion machinery between Antheraea and Bombyx fibroins, we introduced the genomic A. yamamai fibroin gene into the domesticated silkworm, B. mori. The spliced A. yamamai fibroin mRNA appeared only in the posterior region of the silk gland of the transgenic silkworm, suggesting that the functions of the fibroin promoter region and the splicing machinery are conserved between these two species. The A. yamamai fibroin protein was detected in the lumen of the silk gland of the transgenic silkworm, albeit at lower levels compared with the B. mori-type fibroin. We found a strong degeneration of the posterior region of the silk gland of the transgenic silkworm. As a result, the cocoon shell weight was much lower in the transgenic silkworm than in the non-transgenic line. These results indicate that the promoter function and splicing machinery are well conserved between A. yamamai and B. mori but that the secretion mechanism of fibroin is diversified between the two.

  13. Supercritical Carbon Dioxide Extraction of the Oak Silkworm (Antheraea pernyi) Pupal Oil: Process Optimization and Composition Determination

    OpenAIRE

    Zhao-Jun Wei; Zeng Dong; Ai-Mei Liao; Wen-Juan Pan; Jian-Guo Zhang

    2012-01-01

    Supercritical carbon dioxide (SC-CO2) extraction of oil from oak silkworm pupae was performed in the present research. Response surface methodology (RSM) was applied to optimize the parameters of SC-CO2 extraction, including extraction pressure, temperature, time and CO2 flow rate on the yield of oak silkworm pupal oil (OSPO). The optimal extraction condition for oil yield within the experimental range of the variables researched was at 28.03 MPa, 1.83 h, 35.31 °C and 20.26 L/h as flow rate o...

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

    Science.gov (United States)

    Fedic, Robert; Zurovec, Michal; Sehnal, Frantisek

    2003-09-12

    The fiber properties of lepidopteran silk depend on the amino acid repeats that interact during H-fibroin polymerization. The aim of our research was to relate repeat composition to insect biology and fiber strength. Representative regions of the H-fibroin genes were sequenced and analyzed in three pyralid species: wax moth (Galleria mellonella), European flour moth (Ephestia kuehniella), and Indian meal moth (Plodia interpunctella). The amino acid repeats are species-specific, evidently a diversification of an ancestral region of 43 residues, and include three types of regularly dispersed motifs: modifications of GSSAASAA sequence, stretches of tripeptides GXZ where X and Z represent bulky residues, and sequences similar to PVIVIEE. No concatenations of GX dipeptide or alanine, which are typical for Bombyx silkworms and Antheraea silk moths, respectively, were found. Despite different repeat structure, the silks of G. mellonella and E. kuehniella exhibit similar tensile strength as the Bombyx and Antheraea silks. We suggest that in these latter two species, variations in the repeat length obstruct repeat alignment, but sufficiently long stretches of iterated residues get superposed to interact. In the pyralid H-fibroins, interactions of the widely separated and diverse motifs depend on the precision of repeat matching; silk is strong in G. mellonella and E. kuehniella, with 2-3 types of long homogeneous repeats, and nearly 10 times weaker in P. interpunctella, with seven types of shorter erratic repeats. The high proportion of large amino acids in the H-fibroin of pyralids has probably evolved in connection with the spinning habit of caterpillars that live in protective silk tubes and spin continuously, enlarging the tubes on one end and partly devouring the other one. The silk serves as a depot of energetically rich and essential amino acids that may be scarce in the diet. PMID:12816957

  15. 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.

  16. Non-Mulberry and Mulberry Silk Protein Sericins as Potential Media Supplement for Animal Cell Culture.

    Science.gov (United States)

    Sahu, Neety; Pal, Shilpa; Sapru, Sunaina; Kundu, Joydip; Talukdar, Sarmistha; Singh, N Ibotambi; Yao, Juming; Kundu, Subhas C

    2016-01-01

    Silk protein sericins, in the recent years, find application in cosmetics and pharmaceuticals and as biomaterials. We investigate the potential of sericin, extracted from both mulberry Bombyx mori and different non-mulberry sources, namely, tropical tasar, Antheraea mylitta; muga, Antheraea assama; and eri, Samia ricini, as growth supplement in serum-free culture medium. Sericin supplemented media containing different concentrations of sericins from the different species are examined for attachment, growth, proliferation, and morphology of fibrosarcoma cells. The optimum sericin supplementation seems to vary with the source of sericins. The results indicate that all the sericins promote the growth of L929 cells in serum-free culture media; however, S. ricini sericin seems to promote better growth of cells amongst other non-mulberry sericins. PMID:27517047

  17. Non-Mulberry and Mulberry Silk Protein Sericins as Potential Media Supplement for Animal Cell Culture

    Directory of Open Access Journals (Sweden)

    Neety Sahu

    2016-01-01

    Full Text Available Silk protein sericins, in the recent years, find application in cosmetics and pharmaceuticals and as biomaterials. We investigate the potential of sericin, extracted from both mulberry Bombyx mori and different non-mulberry sources, namely, tropical tasar, Antheraea mylitta; muga, Antheraea assama; and eri, Samia ricini, as growth supplement in serum-free culture medium. Sericin supplemented media containing different concentrations of sericins from the different species are examined for attachment, growth, proliferation, and morphology of fibrosarcoma cells. The optimum sericin supplementation seems to vary with the source of sericins. The results indicate that all the sericins promote the growth of L929 cells in serum-free culture media; however, S. ricini sericin seems to promote better growth of cells amongst other non-mulberry sericins.

  18. Identification of RAPD and SCAR markers associated with yield traits in the Indian tropical tasar silkworm Antheraea mylitta drury

    Directory of Open Access Journals (Sweden)

    Suhrid R. Dutta

    2012-01-01

    Full Text Available The tropical tasar silkworm, Antheraea mylitta, is a semi-domesticated vanya silk-producing insect of high economic importance. To date, no molecular marker associated with cocoon and shell weights has been identified in this species. In this report, we identified a randomly amplified polymorphic DNA (RAPD marker and examined its inheritance, and also developed a stable diagnostic sequence-characterized amplified region (SCAR marker. Silkworms were divided into groups with high (HCSW and low (LCSW cocoon and shell weights, and the F2 progeny of a cross between these two groups were obtained. DNA from these silkworms was screened by PCR using 34 random primers and the resulting RAPD fragments were used for cluster analysis and discriminant function analysis (DFA. The clustering pattern in a UPGMA-based dendogram and DFA clearly distinguished the HCSW and LCSW groups. Multiple regression analysis identified five markers associated with cocoon and shell weights. The marker OPW16(905 bp showed the most significant association with cocoon and shell weights, and its inheritance was confirmed in F2 progeny. Cloning and sequencing of this 905 bp fragment showed 88% identity between its 134 nucleotides and the Bmc-1/Yamato-like retroposon of A. mylitta. This marker was further converted into a diagnostic SCAR marker (SCOPW 16(826 bp. The SCAR marker developed here may be useful in identifying the right parental stock of tasar silkworms for high cocoon and shell weights in breeding programs designed to enhance the productivity of tasar silk.

  19. Hemocytes and Enzyme-based Route to Evaluate the Impact of Seed Cocoons Preservation Conditions on Antheraea mylitta Pupae

    Directory of Open Access Journals (Sweden)

    B.C. Prasad

    2012-01-01

    Full Text Available Tropical tasar silkworm, Antheraea mylitta Drury DABA-ecorace is commercially exploited in India for tasar silk production. Generally, its cocoons used to preserve in outdoor and indoor conditions. But in recent past, due to global warming, tasar silk zone day time temperature (May-June shoots up and it goes up to 35 to 45C or even more. It cause adverse impact on the survival of tasar silkworm pupae and invite heavy loss to the tasar silk industry. In the present study, hemocyte and enzyme-based methods have been used to evaluate the impact of outdoor and indoor seed cocoon preservation on A. mylitta pupae. Interestingly, differences in Total Hemocyte Count (THC, hemocyte contour/morphology, protein concentration, fat body and hemolymph acid phosphatase (Acp activity of outdoor and indoor preserved pupae have been observed. Marked variation in THC was observed among high, low and median weight pupae. Although, no significant variation was observed in THC of indoor and outdoor preserved female pupae but significant difference was found in male pupae of both the preservation conditions. Differential profile of hemocytes was differing in outdoor and indoor conditions with change in cell-contour. Elevation in immune cell plasmatocytes (PLs numbers was recorded in indoor preserved cocoon. Acp activity in fat body of indoor preserved pupae was higher than outdoor but reverse trend was found in hemolymph. Activity profile Acp vary in male and female with higher, lower and median weight pupae. Protein concentration in hemolymph of outdoor preserved pupae was more in comparison to indoor but this trend was found usually reverse in fat body. In addition, less protein concentration was recorded in fat body and hemolymph of male pupae in contrast to female. It is expected that, based on hemocyte and enzyme-based method impact of cocoon preservation conditions on A. mylitta pupae can be evaluated/observed.

  20. Heavily nitrogen doped, graphene supercapacitor from silk cocoon

    International Nuclear Information System (INIS)

    Doping of graphene with nitrogen is of much interest, since it improves the overall conductivity and supercapacitive properties. Besides conductivity, nitrogen doping also enhances the pseudo-capacitance due to fast and reversible surface redox processes. In this work, we have developed a cheap and easy process for synthesizing heavily nitrogen doped graphene (15% nitrogen) from non-mulberry silk cocoon membrane (Tassar, Antheraea mylitta) by pyrolyzing the cocoon at 400 °C in argon atmosphere. Further we have investigated the performance of this heavily ‘nitrogen doped graphene’ (NDG) in a supercapacitor device. Our results suggest that NDG obtained from cocoon has improved supercapacitor performance. The improved performance is due to the high electronegativity of nitrogen that forms dipoles on the graphene surface. These dipoles consequently enhance the tendency of graphene to attract charged species to its surface. This is a green and clean synthesis approach for developing electronic materials for energy applications

  1. Strain Rate and Anisotropic Microstructure Dependent Mechanical Behaviors of Silkworm Cocoon Shells

    OpenAIRE

    Xu, Jun; Zhang, Wen; Gao, Xiang; Meng, Wanlin; Guan, Juan

    2016-01-01

    Silkworm cocoons are multi-layered composite structures comprised of high strength silk fiber and sericin, and their mechanical properties have been naturally selected to protect pupas during metamorphosis from various types of external attacks. The present study attempts to gain a comprehensive understanding of the mechanical properties of cocoon shell materials from wild silkworm species Antheraea pernyi under dynamic loading rates. Five dynamic strain rates from 0.00625 s-1 to 12.5 s-1 are...

  2. Radiation degradation of silk

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-03-01

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

  3. Purification and biochemical characterization of a 70 kDa sericin from tropical tasar silkworm, Antheraea mylitta.

    Science.gov (United States)

    Dash, Rupesh; Ghosh, Sudip K; Kaplan, David L; Kundu, S C

    2007-05-01

    Sericin isolated from the cocoon of the tropical tasar silkmoth Antheraea mylitta showed three major bands, with the lowest 70 kDa. This band was purified by anion exchange chromatography. Immunoblotting with concanavalin-A suggests a glycoprotein and CD analysis of secondary structure includes beta-sheet. Amino acid analysis shows that the protein is enriched in glycine and serine while the mole percentages of these two amino acids are different from sericin of mulberry silkworm. An anti A. mylitta sericin antibody was able to cross-react with sericin from A. assamensis but not the sericin of Bombyx mori and Philosamia ricini. Immunoblot analysis with proteins isolated from middle silk gland of A. mylitta at different developmental stages of larva showed that the 70 kDa sericin is developmentally regulated. These data extend the range of biochemical features found in this unusual family of proteins and may help in developing an improved understanding of their role in forming environmentally stable fibroin fiber-sericin composite structures (cocoons). PMID:17350301

  4. 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. PMID:25982316

  5. 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)

  6. New application of silk protein

    International Nuclear Information System (INIS)

    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)

  7. 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,...

  8. Clicking caterpillars: acoustic aposematism in Antheraea polyphemus and other Bombycoidea.

    Science.gov (United States)

    Brown, Sarah G; Boettner, George H; Yack, Jayne E

    2007-03-01

    Acoustic signals produced by caterpillars have been documented for over 100 years, but in the majority of cases their significance is unknown. This study is the first to experimentally examine the phenomenon of audible sound production in larval Lepidoptera, focusing on a common silkmoth caterpillar, Antheraea polyphemus (Saturniidae). Larvae produce airborne sounds, resembling ;clicks', with their mandibles. Larvae typically signal multiple times in quick succession, producing trains that last over 1 min and include 50-55 clicks. Individual clicks within a train are on average 24.7 ms in duration, often consisting of multiple components. Clicks are audible in a quiet room, measuring 58.1-78.8 dB peSPL at 10 cm. They exhibit a broadband frequency that extends into the ultrasound spectrum, with most energy between 8 and 18 kHz. Our hypothesis that clicks function as acoustic aposematic signals, was supported by several lines of evidence. Experiments with forceps and domestic chicks correlated sound production with attack, and an increase in attack rate was positively correlated with the number of signals produced. In addition, sound production typically preceded or accompanied defensive regurgitation. Bioassays with invertebrates (ants) and vertebrates (mice) revealed that the regurgitant is deterrent to would-be predators. Comparative evidence revealed that other Bombycoidea species, including Actias luna (Saturniidae) and Manduca sexta (Sphingidae), also produce airborne sounds upon attack, and that these sounds precede regurgitation. The prevalence and adaptive significance of warning sounds in caterpillars is discussed. PMID:17337712

  9. 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,

  10. Cellular and Biochemical Changes of Antheraea mylitta D. on Immunization with Attenuated Antheraea mylitta Cytoplasmic Polyhedrosis Virus

    Directory of Open Access Journals (Sweden)

    Phani Kiran Kumar

    2011-01-01

    Full Text Available The aim of the present study is to analyze the cellular and biochemical changes noticed in tasar silkworm larva (Antheraea mylitta D. immunized with attenuated cytoplasmic polyhedrosis virus (AmCPV. The bioassay was carried out to confirm the no induction of disease in attenuated AmCPV inoculated larvae. Total Haemocytes count and Differential Haemocytes counts were carried out in healthy control, immunized and non immunized silkworm larvae at different time intervals. The hemolymph proteins were estimated in healthy control, immunized and non immunized silkworm larvae. The results confirm that, attenuated AmCPV provides protection against AmCPV infection for a short period (6 to 8 days. The mortality in immunized silkworms was reduced significantly as compared to non immunized inoculated control. The total haemocyte counts increased in haemolymph up to 8th day in immunized silkworms in comparison with non immunized inoculated control indicating the positive haemocyte mediated response in silkworm immunized with attenuated AmCPV. Similarly, differential haemocyte count was different in immunized silkworms from the inoculated control. The prohaemocyte, plasmatocytes and granulocytes were maximum in number whereas oenocytoids were minimum in number. The number of degenerated blood cells was increased in inoculated control up to 8th days of post inoculation. The hemolymph protein in immunized silkworms was significantly higher than non immunized control. The gradual increase 1st day to 8th day was observed in immunized silkworm. In non immunized inoculated control, the total hemolymph proteins have shown increasing trend from 1st to 5th day and decreasing from 6th day onwards.

  11. Characterization and pathogenicity assessment of gut-associated microbes of muga silkworm Antheraea assamensis Helfer (Lepidoptera: Saturniidae).

    Science.gov (United States)

    Haloi, Kishor; Kalita, Moni Kankana; Nath, Ramesh; Devi, Dipali

    2016-07-01

    Antheraea assamensis Helfer (muga silkworm) is an economically important endemic insect species of North Eastern Region of India. The silkworm is often susceptible to infection by pathogenic bacteria, leads to a disease commonly known as flacherie which causes 40% loss per annum to the silk industry. In this study, we have reported isolation, characterization and pathogenicity assessment of gut-associated bacteria of healthy and diseased muga silkworms. Thirty five bacterial isolates were screened from the gut of healthy and diseased silkworms by morphological observation and biochemical tests. 11 and 5 strains from healthy and diseased silkworm respectively were identified by 16S rRNA gene sequencing and analyzed. Pseudomonas aeruginosa (DRK1), Ornithinibacillus bavariensis (DRK2), Achromobacter xylosoxidans (KH3) and Staphylococcus aureus (FLG1) strains were commonly found in healthy as well as diseased larvae whereas, Bacillus thuringiensis (MK1) was found only in diseased larvae. Survivability analysis was performed with the identified strains by injection and oral administration (10(4)CFU/ml). The immune response of the silkworm against the pathogen was also studied by phenoloxidase and lysozyme enzyme activity assay, total and differential hemocyte count and phagocytic activity of hemocytes. It was observed that S. aureus, P. aeruginosa and B. thuringiensis significantly reduced the survivability of silkworm (p<0.001) hence found highly pathogenic. The lethal concentrations (LC50) values of the pathogenic strains were calculated at different time intervals (24, 48, 72 and 96h) within the range from 1.38×10(2) to 3.63×10(7)CFU/ml. The pathogenic groups demonstrated inhibition of phenoloxidase activity and decreased in total hemocyte count after 48h of infection. However, the lysozyme activity increased significantly in the pathogenic groups compared to the control (p<0.05). Granulocytes and plasmatocytes showed phagocytosis whereas; other types of cells did

  12. Biotechnologies based on silk

    Czech Academy of Sciences Publication Activity Database

    Sehnal, František

    Heidelberg: Springer, 2011 - (Vilcinskas, A.), s. 211-224 ISBN 978-90-481-9640-1 R&D Projects: GA ČR GAP502/10/2382 Institutional research plan: CEZ:AV0Z50070508 Keywords : silk Subject RIV: ED - Physiology

  13. Optically switchable natural silk

    International Nuclear Information System (INIS)

    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

  14. Self-assembled silk sericin/poloxamer nanoparticles as nanocarriers of hydrophobic and hydrophilic drugs for targeted delivery

    International Nuclear Information System (INIS)

    In recent times self-assembled micellar nanoparticles have been successfully employed in tissue engineering for targeted drug delivery applications. In this review, silk sericin protein from non-mulberry Antheraea mylitta tropical tasar silk cocoons was blended with pluronic F-127 and F-87 in the presence of solvents to achieve self-assembled micellar nanostructures capable of carrying both hydrophilic (FITC-inulin) and hydrophobic (anticancer drug paclitaxel) drugs. The fabricated nanoparticles were subsequently characterized for their size distribution, drug loading capability, cellular uptake and cytotoxicity. Nanoparticle sizes ranged between 100 and 110 nm in diameter as confirmed by dynamic light scattering. Rapid uptake of these particles into cells was observed in in vitro cellular uptake studies using breast cancer MCF-7 cells. In vitro cytotoxicity assay using paclitaxel-loaded nanoparticles against breast cancer cells showed promising results comparable to free paclitaxel drugs. Drug-encapsulated nanoparticle-induced apoptosis in MCF-7 cells was confirmed by FACS and confocal microscopic studies using Annexin V staining. Up-regulation of pro-apoptotic protein Bax, down-regulation of anti-apoptotic protein Bcl-2 and cleavage of regulatory protein PARP through Western blot analysis suggested further drug-induced apoptosis in cells. This study projects silk sericin protein as an alternative natural biomaterial for fabrication of self-assembled nanoparticles in the presence of poloxamer for successful delivery of both hydrophobic and hydrophilic drugs to target sites.

  15. Self-assembled silk sericin/poloxamer nanoparticles as nanocarriers of hydrophobic and hydrophilic drugs for targeted delivery

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Biman B; Kundu, S C, E-mail: kundu@hijli.iitkgp.ernet.i [Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302 (India)

    2009-09-02

    In recent times self-assembled micellar nanoparticles have been successfully employed in tissue engineering for targeted drug delivery applications. In this review, silk sericin protein from non-mulberry Antheraea mylitta tropical tasar silk cocoons was blended with pluronic F-127 and F-87 in the presence of solvents to achieve self-assembled micellar nanostructures capable of carrying both hydrophilic (FITC-inulin) and hydrophobic (anticancer drug paclitaxel) drugs. The fabricated nanoparticles were subsequently characterized for their size distribution, drug loading capability, cellular uptake and cytotoxicity. Nanoparticle sizes ranged between 100 and 110 nm in diameter as confirmed by dynamic light scattering. Rapid uptake of these particles into cells was observed in in vitro cellular uptake studies using breast cancer MCF-7 cells. In vitro cytotoxicity assay using paclitaxel-loaded nanoparticles against breast cancer cells showed promising results comparable to free paclitaxel drugs. Drug-encapsulated nanoparticle-induced apoptosis in MCF-7 cells was confirmed by FACS and confocal microscopic studies using Annexin V staining. Up-regulation of pro-apoptotic protein Bax, down-regulation of anti-apoptotic protein Bcl-2 and cleavage of regulatory protein PARP through Western blot analysis suggested further drug-induced apoptosis in cells. This study projects silk sericin protein as an alternative natural biomaterial for fabrication of self-assembled nanoparticles in the presence of poloxamer for successful delivery of both hydrophobic and hydrophilic drugs to target sites.

  16. Self-assembled silk sericin/poloxamer nanoparticles as nanocarriers of hydrophobic and hydrophilic drugs for targeted delivery

    Science.gov (United States)

    Mandal, Biman B.; Kundu, S. C.

    2009-09-01

    In recent times self-assembled micellar nanoparticles have been successfully employed in tissue engineering for targeted drug delivery applications. In this review, silk sericin protein from non-mulberry Antheraea mylitta tropical tasar silk cocoons was blended with pluronic F-127 and F-87 in the presence of solvents to achieve self-assembled micellar nanostructures capable of carrying both hydrophilic (FITC-inulin) and hydrophobic (anticancer drug paclitaxel) drugs. The fabricated nanoparticles were subsequently characterized for their size distribution, drug loading capability, cellular uptake and cytotoxicity. Nanoparticle sizes ranged between 100 and 110 nm in diameter as confirmed by dynamic light scattering. Rapid uptake of these particles into cells was observed in in vitro cellular uptake studies using breast cancer MCF-7 cells. In vitro cytotoxicity assay using paclitaxel-loaded nanoparticles against breast cancer cells showed promising results comparable to free paclitaxel drugs. Drug-encapsulated nanoparticle-induced apoptosis in MCF-7 cells was confirmed by FACS and confocal microscopic studies using Annexin V staining. Up-regulation of pro-apoptotic protein Bax, down-regulation of anti-apoptotic protein Bcl-2 and cleavage of regulatory protein PARP through Western blot analysis suggested further drug-induced apoptosis in cells. This study projects silk sericin protein as an alternative natural biomaterial for fabrication of self-assembled nanoparticles in the presence of poloxamer for successful delivery of both hydrophobic and hydrophilic drugs to target sites.

  17. Effect of Silk Protein Processing on Drug Delivery from Silk Films

    OpenAIRE

    Pritchard, Eleanor M.; Hu, Xiao; Finley, Violet; Kuo, Catherine K.; Kaplan, David L.

    2013-01-01

    Sericin removal from the core fibroin protein of silkworm silk is a critical first step in the use of silk for biomaterial-related applications, but degumming can affect silk biomaterial properties, including molecular weight, viscosity, diffusivity and degradation behavior. Increasing the degumming time (10, 30, 60 and 90 min) decreases the average molecular weight of silk protein in solution, silk solution viscosity, and silk film glass transition temperature, and increases the rate of degr...

  18. Induction of Biomolecules in Mature Leaves of Terminalia arjuna Due to Feeding of Antheraea mylitta Drury

    Directory of Open Access Journals (Sweden)

    G. Abraham

    2004-01-01

    Full Text Available Terminalia arjuna is an important food plant of the tasar silkworm, Antheraea mylitta Drury. In this study, we investigated the induction of biomolecules in mature leaves of these plants subjected to insect feeding. Increase in total tannin content, lipid peroxidation, and trypsin inhibitor activity have been observed in mature leaves damaged by the insects. The growth rate of Vth instar larvae of A. mylitta fed on previously damaged foliage reduced by 87.1%. Induction of biomolecules for defense mechanisms in relation to herbivore damage has been discussed.

  19. 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.

  20. Nanocomposite gold-silk nanofibers

    OpenAIRE

    Cohen-Karni, Tzahi; Jeong, Kyung Jae; Tsui, Jonathan H.; Reznor, Gally; Mustata, Mirela; Wanunu, Meni; Graham, Adam; Marks, Carolyn; Bell, David C.; Langer, Robert S; Kohane, Daniel S.

    2012-01-01

    Cell-biomaterial interactions can be controlled by modifying the surface chemistry or nanotopography of the material, to induce cell proliferation and differentiation if desired. Here we combine both approaches in forming silk nanofibers (SNFs) containing gold nanoparticles (AuNPs) and subsequently chemically modifying the fibers. Silk fibroin mixed with gold seed nanoparticles was electrospun to form SNFs doped with gold seed nanoparticles (SNFseed). Following gold reduction, there was a two...

  1. Analytical markers for silk degradation: comparing historic silk and silk artificially aged in different environments

    OpenAIRE

    Vilaplana, Francisco; Nilsson, Johanna; Sommer, Dorte V. P.; Karlsson, Sigbritt

    2014-01-01

    Suitable analytical markers to assess the degree of degradation of historic silk textiles at molecular and macroscopic levels have been identified and compared with silk textiles aged artificially in different environments, namely (i) ultraviolet (UV) exposure, (ii) thermo-oxidation, (iii) controlled humidity and (iv) pH. The changes at the molecular level in the amino acid composition, the formation of oxidative moieties, crystallinity and molecular weight correlate well with the changes in ...

  2. 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.

  3. 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.

  4. Recombinant DNA production of spider silk proteins

    OpenAIRE

    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...

  5. PEGylated Silk Nanoparticles for Anticancer Drug Delivery

    DEFF Research Database (Denmark)

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

    2015-01-01

    Silk has a robust clinical track record and is emerging as a promising biopolymer for drug delivery, including its use as nanomedicine. However, silk-based nanomedicines still require further refinements for full exploitation of their potential; the application of “stealth” design principals is e...... to human breast cancer cells. In conclusion, these results, taken together with prior silk nanoparticle data, support a viable future for silk-based nanomedicines....

  6. Lithium-free processing of silk fibroin.

    Science.gov (United States)

    Zheng, Zhaozhu; Guo, Shaozhe; Liu, Yawen; Wu, Jianbing; Li, Gang; Liu, Meng; Wang, Xiaoqin; Kaplan, David

    2016-09-01

    Silk fibroin protein was purified from Bombyx mori silkworm cocoons using a novel dialysis strategy to avoid fibroin aggregation and pre-mature formation of β-sheets. The degummed silk fibers were dissolved in Ajisawa's reagent, a mixture of CaCl2-EtOH-H2O, that is less expensive than lithium bromide. The dissolved solutions were dialyzed against either water or urea solution with a stepwise decrease in concentration. When the steps of 4 M-2 M-1 M-0 M urea (referred to as silk-TS-4210) were adopted, the purified silk fibroin had smaller aggregates (lithium bromide (silk-Li-0) method. Polyvinyl alcohol-emulsified silk microspheres generated using the purified solution had a similar size distribution and morphology when compared to lithium bromide dissolved solutions, while glycerol-blended silk films showed different mechanical properties. The silk-Li-0 generated films with the highest breaking strength (5.7 MPa ± 0.3) while the silk-TS-4210 had the highest extension at break (215.1% ± 12.5). The films prepared from silk-TS-4210 were cytocompatible to support the adhesion and proliferation of human mesenchymal stem cells, with improvements compared to the other samples likely due to the porous morphology of these films. PMID:27298185

  7. Production of silk sericin/silk fibroin blend nanofibers

    OpenAIRE

    Zhang Xianhua; Tsukada Masuhiro; Morikawa Hideaki; Aojima Kazuki; Zhang Guangyu; Miura Mikihiko

    2011-01-01

    Abstract Silk sericin (SS)/silk fibroin (SF) blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA) solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters o...

  8. Analytical markers for silk degradation: comparing historic silk and silk artificially aged in different environments.

    Science.gov (United States)

    Vilaplana, Francisco; Nilsson, Johanna; Sommer, Dorte V P; Karlsson, Sigbritt

    2015-02-01

    Suitable analytical markers to assess the degree of degradation of historic silk textiles at molecular and macroscopic levels have been identified and compared with silk textiles aged artificially in different environments, namely (i) ultraviolet (UV) exposure, (ii) thermo-oxidation, (iii) controlled humidity and (iv) pH. The changes at the molecular level in the amino acid composition, the formation of oxidative moieties, crystallinity and molecular weight correlate well with the changes in the macroscopic properties such as brightness, pH and mechanical properties. These analytical markers are useful to understand the degradation mechanisms that silk textiles undergo under different degradation environments, involving oxidation processes, hydrolysis, chain scission and physical arrangements. Thermo-oxidation at high temperatures proves to be the accelerated ageing procedure producing silk samples that most resembled the degree of degradation of early seventeenth-century silk. These analytical markers will be valuable to support the textile conservation tasks currently being performed in museums to preserve our heritage. PMID:25492090

  9. Fibroin silk proteins from the nonmulberry silkworm Philosamia ricini are biochemically and immunochemically distinct from those of the mulberry silkworm Bombyx mori.

    Science.gov (United States)

    Ahmad, Raies; Kamra, Anita; Hasnain, Seyed Ehtesham

    2004-03-01

    Silk proteins were isolated from the cocoons of the nonmulberry silkworm, Philosamia ricini. Three polypeptides of 97, 66, and 45 kDa were identified. The 66-kDa molecule represented sericin, whereas the 97-kDa and the 45-kDa polypeptides linked together through a disulfide bond constituted the fibroin protein. Antibodies raised against the 97-kDa P. ricini fibroin heavy chain reacted specifically with this molecule and did not recognize fibroin heavy chain from another nonmulberry silkworm, Antheraea assama or from the mulberry silkworm, Bombyx mori, suggesting the presence of P. ricini species-specific determinants in this heavy chain. Antibodies generated against fibroin light chain of P. ricini also showed similar reactivity pattern. Immunoblot analysis with proteins isolated from the silk glands of P. ricini at different stages of larval development showed that the expression of fibroin heavy chain was developmentally and spatially regulated. The protein was most abundant in the 5th instar larva, and could be detected in the middle and the posterior but not the anterior silk glands. The amino acid composition of the 97-kDa fibroin protein showed abundance of glutamic acid and did not contain (Gly-Ala)(n) motifs, a characteristic feature of B. mori fibroin heavy chain. Our study reveals significant differences between the nonmulberry silkworm P. ricini and the mulberry silkworm B. mori in the biochemical composition and immunochemical characteristics of fibroin heavy chain. These differences might be responsible for the differences seen in the quality of silk produced by these two silkworms. PMID:15068584

  10. Sunlight-Induced Coloration of Silk.

    Science.gov (United States)

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

    2016-12-01

    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. PMID:27297220

  11. Comparative transcriptome analyses on silk glands of six silkmoths imply the genetic basis of silk structure and coloration

    OpenAIRE

    Dong, Yang; Dai, Fangyin; Ren, Yandong; Liu, Hui; Chen, Lei; Yang, Pengcheng; Liu, Yanqun; LI, XIN; Wang, Wen; Xiang, Hui

    2015-01-01

    Background Silk has numerous unique properties that make it a staple of textile manufacturing for several thousand years. However, wider applications of silk in modern have been stalled due to limitations of traditional silk produced by Bombyx mori. While silk is commonly produced by B. mori, several wild non-mulberry silkmoths--especially members of family Saturniidae--produce silk with superior properties that may be useful for wider applications. Further utilization of such silks is hamper...

  12. SILK FIBRE DEGRADATION AND ANALYSIS BY PROTEOMICS

    OpenAIRE

    YUKSELOGLU S. Muge; CANOGLU Suat

    2016-01-01

    Silk is one of the promising natural fibres and has a long established history in textile production throughout the centuries. Silk is produced by cultured silk worms, spiders, scorpions, mites and flies. It is extracellular proteinaceous fibres which consist of highly crystalline and insoluble proteins, the fibroins glued with sericin and an amourphous protein. On the other hand, understanding and controlling the degradation of protein materials are important for determining quality and the...

  13. Genetic characterisation of microsporidia infecting Indian tasar silkworm, Antheraea mylitta, using morphology and molecular tools.

    Science.gov (United States)

    Hassan, Wazid; Surendra Nath, B

    2015-01-01

    The utility of inter simple sequence repeat-PCR (ISSR-PCR) assay in the genetic characterisation and elucidation of the phylogenetic relationship of different microsporidian isolates infecting tropical tasar silkworm, Antheraea mylitta Drury, is demonstrated. A total of 22 different microsporidians collected from the diseased tasar silkworms from Jharkhand state of India were analysed using morphological characters and ISSR-PCR. Observations spores under phase contrast microscope revealed oval to elongate in shape with length ranging from 3.8 μm to 5.1 μm and width from 2.6 μm to 3.3 μm. All the microsporidian isolates except MIJ-1gC showed gonadal infection and transovarial transmission in infected tasar silkworms. Fourteen out of 20 ISSR primers tested generated reproducible profiles and yielded a total of 281 fragments, of which 273 were polymorphic (97%). The degree of banding pattern was used to evaluate genetic distances and for phylogenetic analysis. The results demonstrated that ISSR analysis may be a useful and efficient tool for taxonomical grouping and phylogenetic classification of different microsporidians in general. PMID:26198429

  14. Fabrication of robust Antheraea assama fibroin nanofibrous mat using ionic liquid for skin tissue engineering.

    Science.gov (United States)

    Srivastava, Chandra Mohan; Purwar, Roli

    2016-11-01

    Electrospinning is an emerging technique used for fabrication of nanofibrous mats for skin tissue engineering applications. The aim of this study centered on fabrication of muga fibroin electrospun mats by using ionic liquid and its characterizations. The muga fibroin extracted from cocoon of Antheraea assama is dissolved in 1-butyl, 3-methyl imidazolium acetate (BMIMAc), a green solvent, to prepare a dope solution for electrospinning. The molecular weight, rheology and structural properties of dope solution are characterized. The process parameters of electrospinning machine such as voltage and concentration of dope solution are varied to obtain nanofibrous mats. The nanofibrous mat having average fiber diameter of 160nm are obtained from 10% w/v concentration of muga fibroin in BMIMAc with an applied voltage of 20KV. The mechanical, structural, physical and thermal properties of muga nanofibrous mat (MNF) are analyzed and compare with muga cast film. The cytocompatibility test is performed using L929 fibroblast cells. It is observed that muga nanofibrous mat support higher growth of fibroblast cells (pefficiency of gentamycin sulphate loaded muga nanofibrous mat are found to be significantly higher (pmaterial for skin tissue engineering. PMID:27524022

  15. Generation of cytotoxic molecules and oxidative stress in haemolymph of pebrinised tasar silkworm Antheraea mylitta Drury.

    Science.gov (United States)

    Jena, Karmabeer; Pandey, Jay Prakash; Priya, Anshu; Kundu, Papri; Sinha, Ajit Kumar; Yadav, Harendra; Sahay, Alok

    2016-01-01

    The present study was carried out to investigate the effects of microsporidial infection on redox regulation mechanism and oxidative stress in tasar silkworm Antheraea mylitta. High level of superoxide radical (p < 0.05), nitric oxide (p < 0.001) and lipid peroxidation (p < 0.001) was observed in haemolymph of pebrinised larvae, which indicated the resultant generation of cytotoxic molecules and oxidative damage. Increased phenol oxidase (PO) activity in haemolymph of pebrinised larvae indicated the activation of immune defences during pathological conditions. In addition, higher level of glutathione-S-tranferase (GST) activity and reduced glutathione (GSH) level observed in pebrinised larvae indicated adaptive behaviour of tissue against toxic oxyradicals (p < 0.05). Conversely, low level of ascorbic acid (ASA) content suggested that the larvae might have used these compounds to counteract stress in tissues or low uptake under microspridial infection (p < 0.05). Present findings provide new insights into the cellular and biochemical bases of host-pathogen interactions in tasar silkworm A. mylitta. PMID:26930859

  16. 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 ...

  17. 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.

  18. 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. PMID:26117747

  19. 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

  20. 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

  1. SILK FIBRE DEGRADATION AND ANALYSIS BY PROTEOMICS

    Directory of Open Access Journals (Sweden)

    YUKSELOGLU S.Muge

    2016-05-01

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

  2. Extracted sericin from silk waste for film formation

    OpenAIRE

    Rungsinee Sothornvit; Rungsima Chollakup; Potjanart Suwanruji

    2010-01-01

    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 ex...

  3. Analysis of bacteria-challenged wild silkmoth, Antheraea mylitta (lepidoptera transcriptome reveals potential immune genes

    Directory of Open Access Journals (Sweden)

    John Serene H

    2006-07-01

    Full Text Available Abstract Background In the recent years a strong resemblance has been observed between the insect immune system and the mammalian innate immune mechanisms suggesting their common origin. Among the insects, only the dipterans (Drosophila and various mosquito species have been widely investigated for their immune responses towards diverse pathogens. In the present study we constructed and analysed the immune transcriptome of the lepidopteran Antheraea mylitta, an economically important Indian tasar silkmoth with a view to unravel the potential immune-related genes and pathways. Results An expressed sequence tag (EST library was constructed from mRNA obtained from fat bodies of A. mylitta larvae that had been challenged by infection with Escherichia coli cells. We identified 719 unique ESTs from a total of 1412 sequences so generated. A third of the transcriptome showed similarity with previously characterized immune-related genes that included both the known and putative immune genes. Of the four putative novel defence proteins (DFPs annotated by PSI-BLAST three showed similarity to extracellular matrix proteins from vertebrates implicated in innate immunity, while the fourth was similar to, yet distinct from, the anti-microbial protein cecropin. Finally, we analysed the expression profiles of 15 potential immune-related genes, and the majority of them were induced more prominently with E. coli compared to Micrococcus luteus. We also identified several unknown proteins, some of which could have probable immune-related functions based on the results of the ProDom analysis. Conclusion The present study has identified many potential immune-related genes in A. mylitta some of which are vertebrate homologues and others are hitherto unreported putative defence proteins. Several genes were present as members of gene families, as has also been observed in other insect species.

  4. Potential of inherent RGD containing silk fibroin-poly (Є-caprolactone) nanofibrous matrix for bone tissue engineering.

    Science.gov (United States)

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

    2016-02-01

    The current study deals with the fabrication and characterization of blended nanofibrous scaffolds of tropical tasar silk fibroin of Antheraea mylitta and poly (Є-caprolactone) to act as an ideal scaffold for bone regeneration. The use of poly (Є-caprolactone) in osteogenesis is well-recognized. At the same time, the osteoconductive nature of the non-mulberry tasar fibroin is also established due to its internal integrin binding peptide RGD (Arg-Gly-Asp) sequences, which enhance cellular interaction and proliferation. Considering that the materials have the required and favorable properties, the blends are formed using an equal volume ratio of fibroin (2 and 4 wt%) and poly (Є-caprolactone) solution (10 wt%) to fabricate nanofibers. The nanofibers possess an average diameter of 152 ± 18 nm (2 % fibroin/PCL) and 175 ± 15 nm (4% fibroin/PCL). The results of Fourier transform infrared spectroscopy substantiates the preservation of the secondary structure of the fibroin in the blends indicating the structural stability of the neo-matrix. With an increase in the fibroin percentage, the hydrophobicity and thermal stability of the matrices as measured from melting temperature Tm (using DSC) decrease, while the mechanical strength is improved. The blended nanofibrous scaffolds are biodegradable, and support the viability and proliferation of human osteoblast-like cells as observed through scanning electron and confocal microscopes. Alkaline phosphatase assay indicates the cell proliferation and the generation of the neo-bone matrix. Taken together, these findings illustrate that the silk-poly (Є-caprolactone) blended nanofibrous scaffolds have an excellent prospect as scaffolding material in bone tissue engineering. PMID:26174955

  5. Production of silk sericin/silk fibroin blend nanofibers

    Directory of Open Access Journals (Sweden)

    Zhang Xianhua

    2011-01-01

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

  6. Production of silk sericin/silk fibroin blend nanofibers

    Science.gov (United States)

    Zhang, Xianhua; Tsukada, Masuhiro; Morikawa, Hideaki; Aojima, Kazuki; Zhang, Guangyu; Miura, Mikihiko

    2011-08-01

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

  7. 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.

  8. Sensitization to silk allergen among workers of silk filatures in India: a comparative study

    OpenAIRE

    Gowda, Giriyanna; Shivalingaiah, Anwith Huluvadi; Vijayeendra, Anagha Manakari; Sarkar, Nivedita; Nagaraj, Chitra; Masthi, Nugehally Raju Ramesh

    2016-01-01

    Background Sericulture plays an eminent role in development of rural economy in India. Silk filature is a unit where silk is unwound from the cocoons and the strands are collected into skeins. During the process workers are exposed to the high molecular weight proteins like Sericin and Fibroin which are potent allergens leading to sensitization over a period of time and subsequently occupational related health disorders. Objective To identify and compare the magnitude of silk allergen sensiti...

  9. Construction of a full-length cDNA Library from Chinese oak silkworm pupa and identification of a KK-42-binding protein gene in relation to pupa-diapause termination

    Directory of Open Access Journals (Sweden)

    Yu-Ping Li, Run-Xi Xia, Huan Wang, Xi-Sheng Li, Yan-Qun Liu, Zhao-Jun Wei, Cheng Lu, Zhong-Huai Xiang

    2009-01-01

    Full Text Available In this study we successfully constructed a full-length cDNA library from Chinese oak silkworm, Antheraea pernyi, the most well-known wild silkworm used for silk production and insect food. Total RNA was extracted from a single fresh female pupa at the diapause stage. The titer of the library was 5 × 105 cfu/ml and the proportion of recombinant clones was approximately 95%. Expressed sequence tag (EST analysis was used to characterize the library. A total of 175 clustered ESTs consisting of 24 contigs and 151 singlets were generated from 250 effective sequences. Of the 175 unigenes, 97 (55.4% were known genes but only five from A. pernyi, 37 (21.2% were known ESTs without function annotation, and 41 (23.4% were novel ESTs. By EST sequencing, a gene coding KK-42-binding protein in A. pernyi (named as ApKK42-BP; GenBank accession no. FJ744151 was identified and characterized. Protein sequence analysis showed that ApKK42-BP was not a membrane protein but an extracellular protein with a signal peptide at position 1-18, and contained two putative conserved domains, abhydro_lipase and abhydrolase_1, suggesting it may be a member of lipase superfamily. Expression analysis based on number of ESTs showed that ApKK42-BP was an abundant gene in the period of diapause stage, suggesting it may also be involved in pupa-diapause termination.

  10. Drömmen om svenskt silke

    OpenAIRE

    Johansson Åbonde, Anders

    2010-01-01

    The grandiose, but failed, attempts to produce silk in Sweden in the past have been largely ignored by historians. This thesis describes the history of sericulture in Sweden, including three periods of practical trials in 1735-1765, 1830-1898 and 1913-1918. For a long time, the secrets of sericulture were closely guarded in China but by the beginning of the 16th century, knowledge of silk cultivation techniques had reached a number of European countries. The pursuit of domestic silk productio...

  11. 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.

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

    International Nuclear Information System (INIS)

    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

  13. 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

  14. Silk as an innovative biomaterial for cancer therapy.

    Science.gov (United States)

    Jastrzebska, Katarzyna; Kucharczyk, Kamil; Florczak, Anna; Dondajewska, Ewelina; Mackiewicz, Andrzej; Dams-Kozlowska, Hanna

    2015-01-01

    Silk has been used for centuries in the textile industry and as surgical sutures. In addition to its unique mechanical properties, silk possesses other properties, such as biocompatibility, biodegradability and ability to self-assemble, which make it an interesting material for biomedical applications. Although silk forms only fibers in nature, synthetic techniques can be used to control the processing of silk into different morphologies, such as scaffolds, films, hydrogels, microcapsules, and micro- and nanospheres. Moreover, the biotechnological production of silk proteins broadens the potential applications of silk. Synthetic silk genes have been designed. Genetic engineering enables modification of silk properties or the construction of a hybrid silk. Bioengineered hybrid silks consist of a silk sequence that self-assembles into the desired morphological structure and the sequence of a polypeptide that confers a function to the silk biomaterial. The functional domains can comprise binding sites for receptors, enzymes, drugs, metals or sugars, among others. Here, we review the current status of potential applications of silk biomaterials in the field of oncology with a focus on the generation of implantable, injectable and targeted drug delivery systems and the three-dimensional cancer models based on silk scaffolds for cancer research. However, the systems described could be applied in many biomedical fields. PMID:25859397

  15. 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.

  16. Silver nanoparticle containing silk fibroin bionanotextiles

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. Silk Microgels Formed by Proteolytic Enzyme Activity

    OpenAIRE

    Samal, Sangram K.; Dash, Mamoni; Chiellini, Federica; Kaplan, David L; Chiellini, Emo

    2013-01-01

    The proteolytic enzyme α-chymotrypsin selectively cleaves the amorphous regions of silk fibroin protein (SFP) and allows the crystalline regions to self-assemble into silk microgels (SMG) at physiological temperature. These microgels consist of lamellar crystals in the micrometer scale, in contrast to the nanometer scaled crystals in native silkworm fibers. SDS-PAGE and zeta potential results demonstrated that α-chymotrypsin utilized only the nonamorphous domains or segments of the heavy chai...

  19. Silks as scaffolds for skin reconstruction.

    Science.gov (United States)

    Reimers, Kerstin; Liebsch, Christina; Radtke, Christine; Kuhbier, Jörn W; Vogt, Peter M

    2015-11-01

    In this short review, we describe the use of high molecular weight proteins produced in the glands of several arthropods-commonly called silks-for the purpose to enhance human skin wound healing. To this end an extensive literature search has been performed, the publications have been categorized concerning silk preparation and application and summarized accordingly: Scaffolds to promote wound healing were prepared by processing the silks in different ways including solubilization of the protein fibers followed by casting or electrospinning. The silk scaffolds were additionally modified by coating or blending with the intention of further functionalization. In several approaches, the scaffolds were also vitalized with skin cells or stem cells. In vitro and in vivo models were implied to test for safety and efficiency. We conclude that silk scaffolds are characterized by an advantageous biocompatibility as well as an impressive versatility rendering them ideally suited for application in wounds. Nevertheless, further investigation is needed to exploit the full capacity of silk in different wound models and to achieve clinical transfer in time. PMID:25995140

  20. 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. PMID:25545462

  1. 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)

  2. 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)

  3. Radiation degradation of silk protein

    International Nuclear Information System (INIS)

    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(CaCl2/C2H5OH/H2O=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)

  4. Cloning, overexpression, purification, crystallization and preliminary X-ray diffraction analysis of glyceraldehyde-3-phosphate dehydrogenase from Antheraea mylitta

    International Nuclear Information System (INIS)

    The cloning, overexpression, purification, crystallization and preliminary X-ray crystallographic analysis of glyceraldehyde-3-phosphate dehydrogenase from A. mylitta are reported. Glyceraldehyde-3-phosphate dehydrogenase from Antheraea mylitta (AmGAPDH) was cloned in pQE30 vector, overexpressed in Escherichia coli M15 (pREP4) cells and purified to homogeneity. The protein was crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to the orthorhombic space group I222, with unit-cell parameters a = 85.81, b = 133.72, c = 220.37 Å. X-ray diffraction data were collected and processed to a maximum resolution of 2.2 Å. The presence of three molecules in the asymmetric unit gave a Matthews coefficient (VM) of 2.80 Å3 Da−1, with a solvent content of 56.08%

  5. Microdissection of black widow spider silk-producing glands.

    Science.gov (United States)

    Jeffery, Felicia; La Mattina, Coby; Tuton-Blasingame, Tiffany; Hsia, Yang; Gnesa, Eric; Zhao, Liang; Franz, Andreas; Vierra, Craig

    2011-01-01

    Modern spiders spin high-performance silk fibers with a broad range of biological functions, including locomotion, prey capture and protection of developing offspring. Spiders accomplish these tasks by spinning several distinct fiber types that have diverse mechanical properties. Such specialization of fiber types has occurred through the evolution of different silk-producing glands, which function as small biofactories. These biofactories manufacture and store large quantities of silk proteins for fiber production. Through a complex series of biochemical events, these silk proteins are converted from a liquid into a solid material upon extrusion. Mechanical studies have demonstrated that spider silks are stronger than high-tensile steel. Analyses to understand the relationship between the structure and function of spider silk threads have revealed that spider silk consists largely of proteins, or fibroins, that have block repeats within their protein sequences. Common molecular signatures that contribute to the incredible tensile strength and extensibility of spider silks are being unraveled through the analyses of translated silk cDNAs. Given the extraordinary material properties of spider silks, research labs across the globe are racing to understand and mimic the spinning process to produce synthetic silk fibers for commercial, military and industrial applications. One of the main challenges to spinning artificial spider silk in the research lab involves a complete understanding of the biochemical processes that occur during extrusion of the fibers from the silk-producing glands. Here we present a method for the isolation of the seven different silk-producing glands from the cobweaving black widow spider, which includes the major and minor ampullate glands [manufactures dragline and scaffolding silk], tubuliform [synthesizes egg case silk], flagelliform [unknown function in cob-weavers], aggregate [makes glue silk], aciniform [synthesizes prey wrapping and egg

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

    OpenAIRE

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

    2010-01-01

    Abstract 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 paramet...

  7. New Evidence for Early Silk in the Indus Civilization

    OpenAIRE

    Good, I. L.; Kenoyer, J. M.; Meadow, Richard Henry

    2009-01-01

    Silk is an important economic fibre, and is generally considered to have been the exclusive cultural heritage of China. Silk weaving is evident from the Shang period c. 1600–1045 bc, though the earliest evidence for silk textiles in ancient China may date to as much as a millennium earlier. Recent microscopic analysis of archaeological thread fragments found inside copper-alloy ornaments from Harappa and steatite beads from Chanhu-daro, two important Indus sites, have yielded silk fibres, dat...

  8. Silk as an innovative biomaterial for cancer therapy

    OpenAIRE

    Jastrzebska, Katarzyna; Kucharczyk, Kamil; Florczak, Anna; Dondajewska, Ewelina; Mackiewicz, Andrzej; Dams-Kozlowska, Hanna

    2014-01-01

    Silk has been used for centuries in the textile industry and as surgical sutures. In addition to its unique mechanical properties, silk possesses other properties, such as biocompatibility, biodegradability and ability to self-assemble, which make it an interesting material for biomedical applications. Although silk forms only fibers in nature, synthetic techniques can be used to control the processing of silk into different morphologies, such as scaffolds, films, hydrogels, microcapsules, an...

  9. Speeding up the Internationalization of Raw Silk Standard

    Institute of Scientific and Technical Information of China (English)

    Hu Zuozhong; Du Zhouhe

    2005-01-01

    @@ China is the main silk producer in the world,whose RSS (Raw Silk Standard) is widely approved in international trade. After entering WTO, China needs to revise the RSS according to the changes of silk industry and develop advanced electronic testing system and improve testing means, so as to promote the internationlization of the RSS.

  10. Post-secretion processing influences spider silk performance.

    Science.gov (United States)

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

    2012-10-01

    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

  11. Woven silk fabric-reinforced silk nanofibrous scaffolds for regenerating load-bearing soft tissues.

    Science.gov (United States)

    Han, F; Liu, S; Liu, X; Pei, Y; Bai, S; Zhao, H; Lu, Q; Ma, F; Kaplan, D L; Zhu, H

    2014-02-01

    Although three-dimensional (3-D) porous regenerated silk scaffolds with outstanding biocompatibility, biodegradability and low inflammatory reactions have promising application in different tissue regeneration, the mechanical properties of regenerated scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This study presents woven silk fabric-reinforced silk nanofibrous scaffolds aimed at dermal tissue engineering. To improve the mechanical properties, silk scaffolds prepared by lyophilization were reinforced with degummed woven silk fabrics. The ultimate tensile strength, elongation at break and suture retention strength of the scaffolds were significantly improved, providing suitable mechanical properties strong enough for clinical applications. The stiffness and degradation behaviors were then further regulated by different after-treatment processes, making the scaffolds more suitable for dermal tissue regeneration. The in vitro cell culture results indicated that these scaffolds maintained their excellent biocompatibility after being reinforced with woven silk fabrics. Without sacrifice of porous structure and biocompatibility, the fabric-reinforced scaffolds with better mechanical properties could facilitate future clinical applications of silk as matrices in skin repair. PMID:24090985

  12. Bio-functionalized silk hydrogel microfluidic systems.

    Science.gov (United States)

    Zhao, Siwei; Chen, Ying; Partlow, Benjamin P; Golding, Anne S; Tseng, Peter; Coburn, Jeannine; Applegate, Matthew B; Moreau, Jodie E; Omenetto, Fiorenzo G; Kaplan, David L

    2016-07-01

    Bio-functionalized microfluidic systems were developed based on a silk protein hydrogel elastomeric materials. A facile multilayer fabrication method using gelatin sacrificial molding and layer-by-layer assembly was implemented to construct interconnected, three dimensional (3D) microchannel networks in silk hydrogels at 100 μm minimum feature resolution. Mechanically activated valves were implemented to demonstrate pneumatic control of microflow. The silk hydrogel microfluidics exhibit controllable mechanical properties, long-term stability in various environmental conditions, tunable in vitro and in vivo degradability in addition to optical transparency, providing unique features for cell/tissue-related applications than conventional polydimethylsiloxane (PDMS) and existing hydrogel-based microfluidic options. As demonstrated in the work here, the all aqueous-based fabrication process at ambient conditions enabled the incorporation of active biological substances in the bulk phase of these new silk microfluidic systems during device fabrication, including enzymes and living cells, which are able to interact with the fluid flow in the microchannels. These silk hydrogel-based microfluidic systems offer new opportunities in engineering active diagnostic devices, tissues and organs that could be integrated in vivo, and for on-chip cell sensing systems. PMID:27077566

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

    Directory of Open Access Journals (Sweden)

    Lu Shen-Zhou

    2014-01-01

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

  14. Biomedical Applications of Mulberry Silk and its Proteins: A Review

    Science.gov (United States)

    Nivedita, S.; Sivaprasad, V.

    2014-04-01

    Silk is a natural fibre used mainly for aesthetic purposes. It has also been used for making surgical sutures for centuries. The recent rediscovery of silk's biological properties have led to new areas of research and utilization in cosmetic, health and medical fields. The silk proteins, fibroin and sericin are processed into biomaterials because of bio-compatibility, bio-degradability, excellent mechanical properties, thermo tolerance and UV protective properties. Silk proteins could be obtained as pure liquids and regenerated in different forms suitable for tissue engineering applications. This paper presents some of the biomedical products and biomaterials made from native, degraded and regenerated silk and their fabrication techniques.

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

    Science.gov (United States)

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

    2016-01-01

    Silk based biomaterials have not only carved a unique niche in the domain of regenerative medicine but new avenues are also being explored for lab-on-a-chip applications. It is pertinent to note that biospinning of silk represents nature's signature microfluidic-maneuver. Elucidation of non-Newtonian flow of silk in the glands of spiders and silkworms has inspired researchers to fabricate devices for continuous extrusion and concentration of silk. Microfluidic channel networks within porous silk scaffolds ensure optimal nutrient and oxygen supply apart from serving as precursors for vascularization in tissue engineering applications. On the other hand, unique topographical features and surface wettability of natural silk fibers have inspired development of a number of simple and cost-effective devices for applications like blood typing and chemical sensing. This review mirrors the recent progress and challenges in the domain of silk-microfluidics for prospective avant-garde applications in the realm of biotechnology. PMID:27165254

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

    Directory of Open Access Journals (Sweden)

    Shigeharu Takiya

    2016-05-01

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

  17. 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.)

  18. 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. PMID:26684370

  19. 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 Caravan: An Adventure…

  20. Silks produced by insect labial glands

    Czech Academy of Sciences Publication Activity Database

    Sehnal, František; Sutherland, T.

    Austin: Landes Bioscience, 2008 - (Scheibel, T.), s. 106-120 ISBN 978-1-58706-316-9 R&D Projects: GA AV ČR IAA5007402 Institutional research plan: CEZ:AV0Z50070508 Keywords : silks * Insect * labial glands Subject RIV: ED - Physiology

  1. Silks produced by insect labial glands

    Czech Academy of Sciences Publication Activity Database

    Sehnal, František; Sutherland, T.

    2008-01-01

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

  2. 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)

  3. 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 (inner diameter). We report on the development of silk fibroin microtubes for blood vessel repair with several advantages over existing scaffold materials/designs. These microtubes were prepared by dipping straight lengths of stainless 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. PMID:17727944

  4. 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.

  5. 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)

  6. 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.

  7. 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. PMID:25761231

  8. 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.

  9. A comparative phylogenetic analysis of full-length mariner elements isolated from the Indian tasar silkmoth, Antheraea mylitta (Lepidoptera: saturniidae)

    Indian Academy of Sciences (India)

    M Dharma Prasad; J Nagaraju

    2003-06-01

    Mariner like elements (MLEs) are widely distributed type II transposons with an open reading frame (ORF) for transposase. We studied comparative phylogenetic evolution and inverted terminal repeat (ITR) conservation of MLEs from Indian saturniid silkmoth, Antheraea mylitta with other full length MLEs submitted in the database. Full length elements from A. mylitta were inactive with multiple mutations. Many conserved amino acid blocks were identified after aligning transposase sequences. Mariner signature sequence, DD(34)D was almost invariable although a few new class of elements had different signatures. A. mylitta MLEs (Anmmar) get phylogenetically classified under cecropia subfamily and cluster closely with the elements from other Bombycoidea superfamily members implying vertical transmission from a common ancestor. ITR analysis showed a conserved sequence of AGGT(2-8N)ATAAGT for forward repeat and AGGT(2-8N)ATGAAAT for reverse repeat. These results and additional work may help us to understand the dynamics of MLE distribution in A. mylitta and construction of appropriate vectors for mariner mediated transgenics.

  10. Qualitative and Quantitative Changes in Protein Profile of Various Tissue of Tropical Tasar Silkworm, Antheraea mylitta Drury

    Directory of Open Access Journals (Sweden)

    P.K. Mishra

    2011-01-01

    Full Text Available In the present study, quantitative and qualitative changes in protein profile of different tissue of larvae, pupae, adult and eggs of Tasar silkworm Antheraea mylitta Drury was investigated. Stage and age dependent variation in protein concentration and SDS-PAGE protein profile of 36 and 64 kDa protein was observed in different tissue. The concentration of protein was recorded higher in eggs laid by fresh moth than 3 days old moth and significant variation was also noticed in normal and depressed eggs. Interestingly, substantial changes in SDS-PAGE protein profile was observed in normal and depressed eggs and eggs laid by fresh moth than 3 days old moth. Haemolymph and midgut protein concentration was recorded higher in 3rd and 5th instar feeding larvae and in 4th instar mature larvae. Concentration of protein in the haemolymph of pupae before the brain window becomes opaque was higher in both the sexes than opaque stage. Fat body protein concentration in larvae showed increasing trend from 3rd to 5th instar larvae and it was higher in pupae after the brain window becomes opaque and fresh moth. In addition, higher protein concentration was recorded in gonads of pupae after the brain window becomes opaque and in reproductive organs of fresh moth. Present findings would promote to further understand the precise reason for depression of eggs and changes in protein profile in different tissue of A. mylitta.

  11. Controlling silk fibroin particle features for drug delivery

    OpenAIRE

    Lammel, Andreas; Hu, Xiao; Park, Sang-Hyug; Kaplan, David L.; Scheibel, Thomas

    2010-01-01

    Silk proteins are a promising material for drug delivery due to their aqueous processability, biocompatibility, and biodegradability. A simple aqueous preparation method for silk fibroin particles with controllable size, secondary structure and zeta potential is reported. The particles were produced by salting out a silk fibroin solution with potassium phosphate. The effect of ionic strength and pH of potassium phosphate solution on the yield and morphology of the particles was determined. Se...

  12. Identification and classification of silks using infrared spectroscopy

    OpenAIRE

    M. Boulet-Audet; Vollrath, F.; Holland, C.

    2015-01-01

    ABSTRACT Lepidopteran silks number in the thousands and display a vast diversity of structures, properties and industrial potential. To map this remarkable biochemical diversity, we present an identification and screening method based on the infrared spectra of native silk feedstock and cocoons. Multivariate analysis of over 1214 infrared spectra obtained from 35 species allowed us to group silks into distinct hierarchies and a classification that agrees well with current phylogenetic data an...

  13. Elasto-capillary windlass : from spider silk to smart actuators

    OpenAIRE

    Elettro, Hervé

    2015-01-01

    This PhD work aimed to understand and recreate artificially a self-assembling mechanism involving capillarity and elasticity present in spider silk. The primary function of the micronic glue droplets that exist on spider capture silk is to provide the spider web with adhesive properties. These droplets play yet another role: the dramatic enhancement of silk mechanical properties, as well as the preservation of the integrity of the web structure. The localization of the buckling instability wi...

  14. Silk Fibroin Encapsulated Powder Reservoirs for Sustained Release of Adenosine

    OpenAIRE

    Pritchard, Eleanor M.; Szybala, Cory; Boison, Detlev; Kaplan, David L.

    2010-01-01

    Due to its unique properties, silk fibroin was studied as a biodegradable polymer vehicle for sustained, local delivery of the anticonvulsant adenosine from encapsulated reservoirs. Silk is a biologically derived protein polymer that is biocompatible, mechanically strong and degrades to non-toxic products in vivo. To achieve local, sustained, controlled adenosine release from fully degradable implants, solid adenosine powder reservoirs were coated with silk fibroin. Material properties of the...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  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. The Consolidation Behavior of Silk Hydrogels

    OpenAIRE

    Kluge, Jonathan A.; Rosiello, Nicholas C.; Leisk, Gary G.; Kaplan, David L.; Dorfmann, A. Luis

    2009-01-01

    Hydrogels have mechanical properties and structural features that are similar to load bearing soft tissues including intervertebral disc and articular cartilage, and can be implanted for tissue restoration or for local release of therapeutic factors. To help predict their performance, mechanical characterization and mathematical modeling are available methods for use in tissue engineering and drug delivery settings. In this study, confined compression creep tests were performed on silk hydrog...

  1. Antioxidant Activities of Iranian Corn Silk

    OpenAIRE

    Ebrahimzadeh, Mohammad Ali; POURMORAD, Fereshteh; HAFEZI, Samira

    2008-01-01

    Traditionally corn silk (CS) has been used as diuretic, antilithiasic, uricosuric, and antiseptic. It is used for the treatment of edema as well as for cystitis, gout, kidney stones, nephritis, and prostatitis. In the present study, the antioxidant properties of ethanol-water extract from CS were estimated by different methods. Also phenol and flavonoid content of the extract were measured by Folin Ciocalteu and AlCl3 assays. CS extract contained a significant amount of phenol and flavonoids....

  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. Injectable Silk Foams for Soft Tissue Regeneration

    OpenAIRE

    Bellas, E.; Lo, T.J.; Fournier, E. P.; Brown, J E; Abbott, R.D.; Gil, E.S.; Marra, K.G.; Rubin, J.P.; Leisk, G.G.; Kaplan, D.L.

    2014-01-01

    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 for the implant and/or grafted tissue to be placed closer to existing vasculature. Here, we demonstrate the feasibility of an injectable silk ...

  4. Orange IV stabilizes silk fibroin microemulsions

    OpenAIRE

    Ferreira, A. V.; Volkov, Vadim; Abreu, Ana S; Azóia, Nuno G.; Botelho, C. M.; Paulo, Artur Cavaco

    2015-01-01

    Silk fibroin (SF) is a natural biopolymer that has been extensively studied in various applications due to its impressive mechanical properties and biocompatibility. Recently, SF-based particles have been proposed as controlled drug delivery systems. A new and efficient method to prepare SF microemulsions (SF-MEs) was developed by oil-in-water emulsions using high-pressure homogenization to promote emulsification. During SF-ME production, the secondary structure of SF changed to a more stable...

  5. Silk constructs for delivery of muskuloskeletal therapeutics

    OpenAIRE

    Meinel, Lorenz; Kaplan, David L.

    2012-01-01

    Silk fibroin (SF) is a biopolymer with distinguishing features from many other bio- as well as synthetic polymers. From a biomechanical and drug delivery perspective, SF combines remarkable versatility for scaffolding (solid implants, hydrogels, threads, solutions), with advanced mechanical properties and good stabilization and controlled delivery of entrapped protein and small molecule drugs, respectively. It is this combination of mechanical and pharmaceutical features which render SF so ex...

  6. Osteogenic signaling on silk-based matrices.

    Science.gov (United States)

    Midha, Swati; Murab, Sumit; Ghosh, Sourabh

    2016-08-01

    Bone tissue engineering has mainly focused on generating 3D grafts to repair bone defects. However, the underlying signaling mechanisms responsible for development of such 3D bone equivalents have largely been ignored. Here we describe the crucial aspects of embryonic osteogenesis and bone development including cell sources and general signaling cascades that guide mesenchymal progenitors towards osteogenic lineage. Drawing from the knowledge of developmental biology, we then review how silk biomaterial can regulate osteogenic signaling by focusing on the expression of cell surface markers, functional genomic information (mRNA) of stem cells cultured on silk matrices. In an attempt to recapitulate exact in vivo microenvironment of osteogenesis, role of scaffold architecture and material chemistry in regulating cellular differentiation is elaborated. The generated knowledge will not only improve our understanding of cell-material interactions but reveal newer strategies beyond a conventional tissue engineering paradigm and open new prospects for developing silk-based therapies against clinically relevant bone disorders. PMID:27163625

  7. Recombinant protein blends: silk beyond natural design.

    Science.gov (United States)

    Dinjaski, Nina; Kaplan, David L

    2016-06-01

    Recombinant DNA technology and new material concepts are shaping future directions in biomaterial science for the design and production of the next-generation biomaterial platforms. Aside from conventionally used synthetic polymers, numerous natural biopolymers (e.g., silk, elastin, collagen, gelatin, alginate, cellulose, keratin, chitin, polyhydroxyalkanoates) have been investigated for properties and manipulation via bioengineering. Genetic engineering provides a path to increase structural and functional complexity of these biopolymers, and thereby expand the catalog of available biomaterials beyond that which exists in nature. In addition, the integration of experimental approaches with computational modeling to analyze sequence-structure-function relationships is starting to have an impact in the field by establishing predictive frameworks for determining material properties. Herein, we review advances in recombinant DNA-mediated protein production and functionalization approaches, with a focus on hybrids or combinations of proteins; recombinant protein blends or 'recombinamers'. We highlight the potential biomedical applications of fibrous protein recombinamers, such as Silk-Elastin Like Polypeptides (SELPs) and Silk-Bacterial Collagens (SBCs). We also discuss the possibility for the rationale design of fibrous proteins to build smart, stimuli-responsive biomaterials for diverse applications. We underline current limitations with production systems for these proteins and discuss the main trends in systems/synthetic biology that may improve recombinant fibrous protein design and production. PMID:26686863

  8. Vibrational spectroscopic study of sulphated silk proteins

    Science.gov (United States)

    Monti, P.; Freddi, G.; Arosio, C.; Tsukada, M.; Arai, T.; Taddei, P.

    2007-05-01

    Degummed Bombyx mori ( B. m.) silk fibroin fabric and mutant naked pupa cocoons (Nd-s) consisting of almost pure silk sericin were treated with chlorosulphonic acid in pyridine and investigated by FT-IR and FT-Raman spectroscopies. Untreated silk fibroin and sericin displayed typical spectral features due to characteristic amino acid composition and molecular conformation (prevailing β-sheet with a less ordered structure in sericin). Upon sulphation, the degree of molecular disorder increased in both proteins and new bands appeared. The IR bands at 1049 and 1014 cm -1 were attributed to vibrations of sulphate salts and that at 1385 cm -1 to the νasSO 2 mode of organic covalent sulphates. In the 1300-1180 cm -1 range various contributions of alkyl and aryl sulphate salts, sulphonamides, sulphoamines and organic covalent sulphates, fell. Fibroin covalently bound sulphate groups through the hydroxyl groups of tyrosine and serine, while sericin through the hydroxyl groups of serine, since the δOH vibrations at 1399 cm -1 in IR and at 1408 cm -1 in Raman disappeared almost completely. Finally, the increase of the I850/ I830 intensity ratio of Raman tyrosine doublet in fibroin suggested a change towards a more exposed state of tyrosine residues, in good agreement with the more disordered conformation taken upon sulphation.

  9. 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. …

  10. 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…

  11. Production of fine powder from silk by radiation

    International Nuclear Information System (INIS)

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

  12. 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)

  13. Transgenic phenolic production in corn silks moderately enhances insect resistance

    Science.gov (United States)

    Some phenolic compounds produced in corn silks, such as maysin, can promote resistance to caterpillar pests. We evaluated transgenic maize engineered to express a maize cDNA controlled by a putative silk specific promoter for secondary metabolite production and corn earworm resistance. Transgene e...

  14. Self-assembly of silk fibroin under osmotic stress

    Science.gov (United States)

    Sohn, Sungkyun

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

  15. 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.

  16. Alleged silk spigots on tarantula feet: electron microscopy reveals sensory innervation, no silk.

    Science.gov (United States)

    Foelix, Rainer; Erb, Bruno; Rast, Bastian

    2013-05-01

    Several studies on tarantulas have claimed that their tarsi could secrete fine silk threads which would provide additional safety lines for maintaining a secure foot-hold on smooth vertical surfaces. This interpretation was seriously questioned by behavioral experiments, and more recently morphological evidence indicated that the alleged spigots ("ribbed hairs") were not secretory but most likely sensory hairs (chemoreceptors). However, since fine structural studies were lacking, the sensory nature was not proven convincingly. By using transmission electron microscopy we here present clear evidence that these "ribbed hairs" contain many dendrites inside the hair lumen - as is the case in the well-known contact chemoreceptors of spiders and insects. For comparison, we also studied the fine structure of regular silk spigots on the spinnerets and found them distinctly different from sensory hairs. Finally, histological studies of a tarantula tarsus did not reveal any silk glands, which, by contrast, are easily found within the spinnerets. In conclusion, the alleged presence of silk spigots on tarantula feet is refuted. PMID:23474440

  17. Chimeric spider silk proteins mediated by intein result in artificial hybrid silks.

    Science.gov (United States)

    Lin, Senzhu; Chen, Gefei; Liu, Xiangqin; Meng, Qing

    2016-07-01

    Hybrid silks hold a great potential as specific biomaterials due to its controlled mechanical properties. To produce fibers with tunable properties, here we firstly made chimeric proteins in vitro, called W2C4CT and W2C8CT, with ligation of MaSp repetitive modules (C) with AcSp modules (W) by intein trans splicing technology from smaller precursors without final yield reduction. Intein mediated chimeric proteins form fibers at a low concentration of 0.4 mg/mL in 50 mM K3 PO4 pH 7.5 just drawn by hand. Hybrid fibers show smoother surface, and also have stronger chemical resistance as compared with fibers from W2CT (W fibers) and mixture of W2CT/C8CT (MHF8 fibers). Fibers from chimeric protein W2C4CT (HFH4) have improved mechanical properties than W fibers; however, with more C modules W2C8CT fibers (HFH8) properties decreased, indicates the length proportion of various modules is very important and should be optimized for fibers with specific properties. Generally, hybrid silks generated via chimeric proteins, which can be simplified by intein trans splicing, has greater potential to produce fibers with tunable properties. Our research shows that intein mediated directional protein ligation is a novel way to make large chimeric spider silk proteins and hybrid silks. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 385-392, 2016. PMID:26948769

  18. The development project of electron irradiated silk material used for restoration of historical silk-mounted painting

    International Nuclear Information System (INIS)

    Many pictures have been painted on the silk materials in Japan. To repair the historical painting, the repairing materials were developed by new silk fibers with electron beam irradiation. Total exposure was about 2 MGy (170 to 230 Mrad). In order to be clear the degradation mechanism of the irradiated silk materials, the samples were irradiated by 254 nm and 365nm UV light and electron beam. The tensile strength of samples decreased with increasing exposure energy. The electron irradiated silk materials showed random clacking and small molecular weight. However, aromatic amino acid of the long wavelength UV light irradiated silk and peptide linkage of the short wavelength UV light irradiated silk were cracked. The historical silk-mounted painting in the Edo era showed decrease of aromatic amino acid peak and that in the Kamakura era not observable peak. Accordingly, the degradation process of historical silk-mounted painting seemed to be the same as the process depend on the long wavelength UV light. (S.Y.)

  19. 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.

  20. 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.

  1. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    International Nuclear Information System (INIS)

    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.

  2. Inhibitory Effect of Corn Silk on Skin Pigmentation

    Directory of Open Access Journals (Sweden)

    Sang Yoon Choi

    2014-03-01

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

  3. 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.

  4. A novel electrospun silk fibroin/hydroxyapatite hybrid nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Jinfa, E-mail: jinfa.ming@gmail.com [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China); Zuo, Baoqi, E-mail: bqzuo@suda.edu.cn [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China)

    2012-11-15

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

  5. A novel electrospun silk fibroin/hydroxyapatite hybrid nanofibers

    International Nuclear Information System (INIS)

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

  6. 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.

  7. Nephila clavipes Flagelliform Silk-like GGX Motifs Contribute to Extensibility and Spacer Motifs Contribute to Strength in Synthetic Spider Silk Fibers

    OpenAIRE

    Adrianos, Sherry L.; Teulé, Florence; Hinman, Michael B.; Jones, Justin A.; Weber, Warner S.; Yarger, Jeffery L.; Lewis, Randolph V.

    2013-01-01

    Flagelliform spider silk is the most extensible silk fiber produced by orb weaver spiders, though not as strong as the dragline silk of the spider. The motifs found in the core of the Nephila clavipes flagelliform Flag protein are: GGX, spacer, and GPGGX. Flag does not contain the polyalanine motif known to provide the strength of dragline silk. To investigate the source of flagelliform fiber strength, four recombinant proteins were produced containing variations of the three core motifs of t...

  8. 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.

  9. 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.

  10. When inordinate tissue growth is beneficial: Improving silk production by increasing silk gland size

    Institute of Scientific and Technical Information of China (English)

    Xavier Bellés

    2011-01-01

    @@ Some 5000 years ago, the legendary Chinese emperor Huang-Ti ordered his wife, Hsi-Ling-Shi, to find out what was damaging his mulberry trees.HsiLing-Shi found white worms eating the mulberry leaves and spinning shiny cocoons.She accidentally dropped a cocoon into her tea cup and saw a delicate, slender thread unwind itself from the cocoon.The young princess had discovered silk [1, 2].

  11. 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.

  12. Thermodynamics Study of Lac Dyeing of Silk Yarn Coated with Chitosan

    Directory of Open Access Journals (Sweden)

    Montra CHAIRAT

    2009-01-01

    Full Text Available A thermodynamic study of lac dyeing of silk pretreated with chitosan at pH 3.0 was investigated in a batch system. It was found that the adsorption of lac dye on silk pretreated with chitosan could be described by the Langmuir isotherm. The results showed that the pretreatment of silk with chitosan provided an enhancement of dye uptake on silk and also decreased the dye desorption from silk yarn compared with the results in the absence of chitosan. The negative value of the enthalpy change (DHº for the adsorption of lac dye on silk pretreated with chitosan indicated that the adsorption process was an exothermic one.

  13. Unravelling the biodiversity of nanoscale signatures of spider silk fibres.

    Science.gov (United States)

    Silva, Luciano P; Rech, Elibio L

    2013-01-01

    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. PMID:24345771

  14. Biopatterning of Silk Proteins for Soft Micro-optics.

    Science.gov (United States)

    Pal, Ramendra K; Kurland, Nicholas E; Wang, Congzhou; Kundu, Subhas C; Yadavalli, Vamsi K

    2015-04-29

    Silk proteins from spiders and silkworms have been proposed as outstanding candidates for soft micro-optic and photonic applications because of their optical transparency, unique biological properties, and mechanical robustness. Here, we present a method to form microstructures of the two constituent silk proteins, fibroin and sericin for use as an optical biomaterial. Using photolithography, chemically modified silk protein photoresists are patterned in 2D arrays of periodic patterns and Fresnel zone plates. Angle-dependent iridescent colors are produced in these periodic micropatterns because of the Bragg diffraction. Silk protein photolithography can used to form patterns on different substrates including flexible sheets with features of any shape with high fidelity and resolution over large areas. Finally, we show that these mechanically stable and transparent iridescent architectures are also completely biodegradable. This versatile and scalable technique can therefore be used to develop biocompatible, soft micro-optic devices that can be degraded in a controlled manner. PMID:25853731

  15. 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

    2016-06-01

    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.

  16. Ptychographic X-ray Tomography of Silk Fiber Hydration

    DEFF Research Database (Denmark)

    Esmaeili, Morteza; Fløystad, Jostein B.; Diaz, Ana; Høydalsvik, Kristin; Guizar-Sicairos, Manuel; Andreasen, Jens Wenzel; Breiby, Dag W.

    2013-01-01

    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....

  17. Characterization of sericin protein recovered from silk wastewaters

    OpenAIRE

    Gökşen Çapar; Seylan Saniye Aygün

    2015-01-01

    INTRODUCTION[|]This study aims to determine the characteristics of sericin protein recovered from silk wastewaters.[¤]METHODS[|]Sericin protein was recovered from silk wastewaters by membrane technology in Engineering Sciences Department of the Middle East Technical University between 2007 and 2008. The protein characterization study was completed in Ankara University Water Management Institute in 2012. The recovered protein was characterized in terms of molecular w...

  18. Review - Trade and Society along the Ancient Silk Road

    OpenAIRE

    Bina Sengar

    2013-01-01

    Review of: Jacqueline H Fewkes. 2011. Trade and Contemporary Society Along the Silk Road: An Ethno-History of Ladakh. London: Routledge. xiii+196pp; list of plates, Ladakh in the twenty-first century is well known as a religious and touristic destination as well as an Indian border territory with Kargil and Siachin - significant military posts. In contrast, the commercial role of Ladakh in trade within the Himalayan region and along the Silk Route is less explored In this w...

  19. 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.

  20. 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.

  1. 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. PMID:26923066

  2. Transmission Electron Microscopy of Bombyx Mori Silk Fibers

    Science.gov (United States)

    Shen, Y.; Martin, D. C.

    1997-03-01

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

  3. Silk Fibroin as Edible Coating for Perishable Food Preservation.

    Science.gov (United States)

    Marelli, B; Brenckle, M A; Kaplan, D L; Omenetto, F G

    2016-01-01

    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. PMID:27151492

  4. Preparation, structure and properties of multi-functional silk via ATRP method

    International Nuclear Information System (INIS)

    In order to develop multi-functional silk materials, silk was grafted using the first flame retardant monomer, dimethyl methacryloyloxyethyl phosphate (DMMEP), and the second antibacterial monomer, dimethylaminoethyl methacrylate (DMAEMA), via atom transfer radical polymerization (ATRP) method. The result of attenuated total reflection-Fourier transformed infrared spectroscopy (ATR-FTIR) indicated that two monomers were successfully grafted onto silk surface. X-ray diffraction (XRD) curves showed that grafting mainly occurred at the amorphous region of silk fibers. Thermal gravimetric analysis (TGA) and flame retardance measurements indicated that the Silk-grafted-poly(DMMEP) (Silk-g-PDMMEP) and Silk-grafted-poly(DMMEP)-blocked-poly(DMAEMA) (Silk-g-PDMMEP-b-PDMAEMA) both had good flame retardance. The LOI value could reach 31.2% and the char length was less than 6 cm for the Silk-g-PDMMEP sample with 22.21% of grafting percentage, and the LOI value was still over 28% after 50 times of washing. And the second grafts of DMAEMA monomer had no distinct effect on the flame retardance of Silk-g-PDMMEP. The inhibition rates of quaternized grafted silk to Staphylococcus aureu and Escherichia coli were both over 88%, and had excellent washing fastness. Multi-functional silk fabric with good flame retardance and anti-bacterial property could be obtained by properly controlling the grafting percentage, which had little effect on the intrinsic properties of silk fabric.

  5. 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.

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

    Science.gov (United States)

    Brooks, Amanda

    2015-11-01

    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.

  7. 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.

  8. Comparative proteomic analysis of the silkworm middle silk gland reveals the importance of ribosome biogenesis in silk protein production.

    Science.gov (United States)

    Li, Jian-ying; Ye, Lu-peng; Che, Jia-qian; Song, Jia; You, Zheng-ying; Yun, Ki-chan; Wang, Shao-hua; Zhong, Bo-xiong

    2015-08-01

    The silkworm middle silk gland (MSG) is the sericin synthesis and secretion unique sub-organ. The molecular mechanisms of regulating MSG protein synthesis are largely unknown. Here, we performed shotgun proteomic analysis on the three MSG subsections: the anterior (MSG-A), middle (MSG-M), and posterior (MSG-P) regions. The results showed that more strongly expressed proteins in the MSG-A were involved in multiple processes, such as silk gland development and silk protein protection. The proteins that were highly expressed in the MSG-M were enriched in the ribosome pathway. MSG-P proteins with stronger expression were mainly involved in the oxidative phosphorylation and citrate cycle pathways. These results suggest that the MSG-M is the most active region in the sericin synthesis. Furthermore, comparing the proteome of the MSG with the posterior silk gland (PSG) revealed that the specific and highly expressed proteins in the MSG were primarily involved in the ribosome and aminoacyl-tRNA biosynthesis pathways. These results indicate that silk protein synthesis is much more active as a result of the enhancement of translation-related pathways in the MSG. These results also suggest that enhancing ribosome biogenesis is important to the efficient synthesis of silk proteins. PMID:26051239

  9. Effect of Processing on Silk-Based Biomaterials: Reproducibility and Biocompatibility

    OpenAIRE

    Wray, Lindsay S.; Hu, Xiao; Gallego, Jabier; Georgakoudi, Irene; Omenetto, Fiorenzo G.; Schmidt, Daniel; Kaplan, David L.

    2011-01-01

    Silk fibroin has been successfully used as a biomaterial for tissue regeneration. In order to prepare silk fibroin biomaterials for human implantation a series of processing steps are required to purify the protein. Degumming to remove inflammatory sericin is a crucial step related to biocompatibility and variability in the material. Detailed characterization of silk fibroin degumming is reported. The degumming conditions significantly affected cell viability on the silk fibroin material and ...

  10. A response to Dolliver's "Evaluating drug trafficking on the Tor Network: Silk Road 2, the sequel"

    OpenAIRE

    Judith Aldridge, David Decary-Hetu

    2015-01-01

    The leading aim of Dolliver's (2015) paper “Evaluating drug trafficking on the Tor Network: Silk Road 2, the sequel” is to document changes in the size and structure of cryptomarkets following the demise of SILK ROAD 1 (SR1) using data she collected from SILK ROAD 2 (SR2), which she casts as successor to its namesake.

  11. Advanced silk material spun by a transgenic silkworm promotes cell proliferation for biomedical application.

    Science.gov (United States)

    Wang, Feng; Xu, Hanfu; Wang, Yuancheng; Wang, Riyuan; Yuan, Lin; Ding, Huan; Song, Chunnuan; Ma, Sanyuan; Peng, Zhixin; Peng, Zhangchuan; Zhao, Ping; Xia, Qingyou

    2014-12-01

    Natural silk fiber spun by the silkworm Bombyx mori is widely used not only for textile materials, but also for biofunctional materials. In the present study, we genetically engineered an advanced silk material, named hSFSV, using a transgenic silkworm, in which the recombinant human acidic fibroblast growth factor (hFGF1) protein was specifically synthesized in the middle silk gland and secreted into the sericin layer to surround the silk fiber using our previously optimized sericin1 expression system. The content of the recombinant hFGF1 in the hSFSV silk was estimated to be approximate 0.07% of the cocoon shell weight. The mechanical properties of hSFSV raw silk fiber were enhanced slightly compared to those of the wild-type raw silk fiber, probably due to the presence of the recombinant of hFGF1 in the sericin layer. Remarkably, the hSFSV raw silk significantly stimulated the cell growth and proliferation of NIH/3T3 mouse embryonic fibroblast cells, suggesting that the mitogenic activity of recombinant hFGF1 was well maintained and functioned in the sericin layer of hSFSV raw silk. These results show that the genetically engineered raw silk hSFSV could be used directly as a fine biomedical material for mass application. In addition, the strategy whereby functional recombinant proteins are expressed in the sericin layer of silk might be used to create more genetically engineered silks with various biofunctions and applications. PMID:24980060

  12. 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

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

    International Nuclear Information System (INIS)

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

  14. 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

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

    International Nuclear Information System (INIS)

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

  16. Structural study on methacrylamide-grafted Tussah silk fibroin fibres.

    Science.gov (United States)

    Pavoni, Eleonora; Tozzi, Silvia; Tsukada, Masuhiro; Taddei, Paola

    2016-07-01

    Tussah silk fibroin fibres were modified by grafting with methacrylamide (MAA), with weight gains ranging between 2.6% and 71.4%. Raman and IR spectroscopic analyses showed that upon grafting the fibres underwent slight conformational changes towards a more unordered state, due to the covalent and hydrogen bonds interactions occurring between the polymer (polyMAA) and the amorphous domains of silk fibres. To test the stability towards alkaline hydrolysis, the untreated and MAA-grafted silk fibres (weight gain of 71.4%) were immersed in NaOH 5% at 50°C for different times; the IR and Raman spectroscopic techniques were utilized to elucidate the degradation mechanism as well as the rearrangements of the fibres induced by the treatment. Upon hydrolysis, both the untreated and grafted fibres underwent an enrichment in β-sheet conformation, due to the preferential removal of the unordered domains. As a result of the covalent interactions with silk fibroin, the polymer increased its stability towards alkaline hydrolysis, since its complete solubilization was avoided and the transformation of its CONH2 groups into COO(-) and COOH was delayed. Vibrational spectroscopy proved to be a valid technique to investigate the mechanism and the effects of the hydrolytic attack, which are both fundamental to design new-generation silk-based materials. PMID:27032490

  17. 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

    2016-01-01

    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. PMID:27216252

  18. 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.

  19. Impact and dynamic mechanical thermal properties of textile silk reinforced epoxy resin composites

    Science.gov (United States)

    Yang, K.; Guan, J.

    2016-07-01

    Silk fabric reinforced epoxy resin composites (SFRPs) were prepared using simple techniques of hand lay-up, hot-press and vacuum treatment, and a series of volume fractions of silk reinforcements were achieved. The impact properties and dynamic mechanical properties of SFRPs were investigated using a pendulum impact testing method and dynamic mechanical thermal analysis (DMTA). The results suggest that silk reinforcement could greatly enhance the mechanical performances of SFRPs. The impact strength reached a maximum of 71 kJ/m2 for 60%-silk SFRP, which demonstrated a potential of silk composites for defence and impact- resistant materials.

  20. Carbonic anhydrase generates a pH gradient in Bombyx mori silk glands.

    Science.gov (United States)

    Domigan, L J; Andersson, M; Alberti, K A; Chesler, M; Xu, Q; Johansson, J; Rising, A; Kaplan, D L

    2015-10-01

    Silk is a protein of interest to both biological and industrial sciences. The silkworm, Bombyx mori, forms this protein into strong threads starting from soluble silk proteins using a number of biochemical and physical cues to allow the transition from liquid to fibrous silk. A pH gradient has been measured along the gland, but the methodology employed was not able to precisely determine the pH at specific regions of interest in the silk gland. Furthermore, the physiological mechanisms responsible for the generation of this pH gradient are unknown. In this study, concentric ion selective microelectrodes were used to determine the luminal pH of B. mori silk glands. A gradient from pH 8.2 to 7.2 was measured in the posterior silk gland, with a pH 7 throughout the middle silk gland, and a gradient from pH 6.8 to 6.2 in the beginning of the anterior silk gland where silk processing into fibers occurs. The small diameter of the most anterior region of the anterior silk gland prevented microelectrode access in this region. Using a histochemical method, the presence of active carbonic anhydrase was identified in the funnel and anterior silk gland of fifth instar larvae. The observed pH gradient collapsed upon addition of the carbonic anhydrase inhibitor methazolamide, confirming an essential role for this enzyme in pH regulation in the B. mori silk gland. Plastic embedding of whole silk glands allowed clear visualization of the morphology, including the identification of four distinct epithelial cell types in the gland and allowed correlations between silk gland morphology and silk stages of assembly related to the pH gradient. B. mori silk glands have four different epithelial cell types, one of which produces carbonic anhydrase. Carbonic anhydrase is necessary for the mechanism that generates an intraluminal pH gradient, which likely regulates the assembly of silk proteins and then the formation of fibers from soluble silk proteins. These new insights into native silk

  1. 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.

  2. The consolidation behavior of silk hydrogels.

    Science.gov (United States)

    Kluge, Jonathan A; Rosiello, Nicholas C; Leisk, Gary G; Kaplan, David L; Dorfmann, A Luis

    2010-04-01

    Hydrogels have mechanical properties and structural features that are similar to load-bearing soft tissues including intervertebral disc and articular cartilage, and can be implanted for tissue restoration or for local release of therapeutic factors. To help predict their performance, mechanical characterization and mathematical modeling are the available methods for use in tissue engineering and drug delivery settings. In this study, confined compression creep tests were performed on silk hydrogels, over a range of concentrations, to examine the phenomenological behavior of the gels under a physiological loading scenario. Based on the observed behavior, we show that the time-dependent response can be explained by a consolidation mechanism, and modeled using Biot's poroelasticity theory. Two observations are in strong support of this modeling framework, namely, the excellent numerical agreement between increasing load step creep data and the linear Terzaghi theory, and the similar values obtained from numerical simulations and direct measurements of the permeability coefficient. The higher concentration gels (8% and 12% w/v) clearly show a strain-stiffening response to creep loading with increasing loads, while the lower concentration gel (4% w/v) does not. A nonlinear elastic constitutive formulation is employed to account for the stiffening. Furthermore, an empirical formulation is used to represent the deformation-dependent permeability. PMID:20142112

  3. Soft magnetic memory of silk cocoon membrane.

    Science.gov (United States)

    Roy, Manas; Dubey, Amarish; Singh, Sushil Kumar; Bhargava, Kalpana; Sethy, Niroj Kumar; Philip, Deepu; Sarkar, Sabyasachi; Bajpai, Alok; Das, Mainak

    2016-01-01

    Silk cocoon membrane (SCM), a solid matrix of protein fiber, responds to light, heat and moisture and converts these energies to electrical signals. Essentially it exhibits photo-electric and thermo-electric properties; making it a natural electro-magnetic sensor, which may influence the pupal development. This raises the question: 'is it only electricity?', or 'it also posses some kind of magnetic memory?' This work attempted to explore the magnetic memory of SCM and confirm its soft magnetism. Fe, Co, Ni, Mn, Gd were found in SCM, in traces, through energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma mass spectrometry (ICP-MS). Presence of iron was ascertained by electron paramagnetic resonance (EPR). In addition, EPR-spectra showed the presence of a stable pool of carbon-centric free radical in the cocoon structure. Carbon-centric free radicals behaves as a soft magnet inherently. Magnetic-Hysteresis (M-H) of SCM confirmed its soft magnetism. It can be concluded that the soft bio-magnetic feature of SCM is due to the entrapment of ferromagnetic elements in a stable pool of carbon centric radicals occurring on the super-coiled protein structure. Natural soft magnets like SCM provide us with models for developing eco-friendly, protein-based biological soft magnets. PMID:27374752

  4. A simple model of multiphoton micromachining in silk hydrogels

    Science.gov (United States)

    Applegate, Matthew B.; Alonzo, Carlo; Georgakoudi, Irene; Kaplan, David L.; Omenetto, Fiorenzo G.

    2016-06-01

    High resolution three-dimensional voids can be directly written into transparent silk fibroin hydrogels using ultrashort pulses of near-infrared (NIR) light. Here, we propose a simple finite-element model that can be used to predict the size and shape of individual features under various exposure conditions. We compare predicted and measured feature volumes for a wide range of parameters and use the model to determine optimum conditions for maximum material removal. The simplicity of the model implies that the mechanism of multiphoton induced void creation in silk is due to direct absorption of light energy rather than diffusion of heat or other photoproducts, and confirms that multiphoton absorption of NIR light in silk is purely a 3-photon process.

  5. Silk moths in Madagascar: Biology, uses and challenges related to Borocera cajani (Boisduval, 1833) (Lepidoptera – Lasiocampidae)

    OpenAIRE

    Razafimanantsoa, Tsiresy; Rajoelison, Gabrielle; Ramamonjisoa, Bruno; Raminosoa,Noromalala; Poncelet, Marc; Bogaert, Jan; Haubruge, Eric; Verheggen, François

    2012-01-01

    Borocera cajani (Lepidoptera, Lasiocampidae), also named Landibe, is main wild silk moth currently used to produce silk textiles in Madagascar. Silk production involve many member of the local population, from the wild silk harvesters, to the spinners, traders, dyers, weavers and the artisans who transform the silk into clothing, accessories and decorative items. Uapaca bojeri (Tapia) forests are the last remnants of highland primary forest, which are threatened by human destruction through b...

  6. Environmentally friendly surface modification of silk fiber: Chitosan grafting and dyeing

    Energy Technology Data Exchange (ETDEWEB)

    Davarpanah, Saideh [Textile Engineering Department, Amirkabir University of Technology, Hafez St., Tehran (Iran, Islamic Republic of); Mahmoodi, Niyaz Mohammad [Textile Engineering Department, Amirkabir University of Technology, Hafez St., Tehran (Iran, Islamic Republic of); Department of Environmental Research, Institute for Colorants, Paint and Coatings, Tehran (Iran, Islamic Republic of)], E-mail: mahmoodi@icrc.ac.ir; Arami, Mokhtar [Textile Engineering Department, Amirkabir University of Technology, Hafez St., Tehran (Iran, Islamic Republic of)], E-mail: arami@aut.ac.ir; Bahrami, Hajir; Mazaheri, Firoozmehr [Textile Engineering Department, Amirkabir University of Technology, Hafez St., Tehran (Iran, Islamic Republic of)

    2009-01-15

    In this paper, the surface modification of silk fiber using anhydrides to graft the polysaccharide chitosan and dyeing ability of the grafted silk were studied. Silk fiber was degummed and acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), in different solvents (dimethyl sulfoxide (DMSO) and N,N-dimethyl formamide (DMF)). The effects of anhydrides, solvents, anhydride concentration, liquor ratio (L:R) and reaction time on acylation of silk were studied. The polysaccharide chitosan was grafted to the acylated silk fiber and dyed by acid dye (Acid Black NB.B). The effects of pH, chitosan concentration, and reaction time on chitosan grafting of acylated silk were investigated. The physical properties show sensible changes regardless of weight gain. Scanning electron microscopy (SEM) analysis showed the presence of foreign materials firmly attached to the surface of silk. FTIR spectroscopy provided evidence that chitosan was grafted onto the acylated silk through the formation of new covalent bonds. The dyeing of the chitosan grafted-acylated silk fiber indicated the higher dye ability in comparison to the acylated and degummed silk samples. The mechanism of chitosan grafting over degummed silk through anhydride linkage was proposed. The findings of this research support the potential production of new environmentally friendly textile fibers. It is worthwhile to mention that the grafted samples have antibacterial potential due to the antibacterial property of chitosan molecules.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-06-15

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

  8. Surface Modification and Characterisation of Silk Fibroin Fabric Produced by the Layer-by-Layer Self-Assembly of Multilayer Alginate/Regenerated Silk Fibroin.

    Directory of Open Access Journals (Sweden)

    Gaotian Shen

    Full Text Available Silk-based medical products have a long history of use as a material for surgical sutures because of their desirable mechanical properties. However, silk fibroin fabric has been reported to be haemolytic when in direct contact with blood. The layer-by-layer self-assembly technique provides a method for surface modification to improve the biocompatibility of silk fibroin fabrics. Regenerated silk fibroin and alginate, which have excellent biocompatibility and low immunogenicity, are outstanding candidates for polyelectrolyte deposition. In this study, silk fabric was degummed and positively charged to create a silk fibroin fabric that could undergo self-assembly. The multilayer self-assembly of the silk fibroin fabric was achieved by alternating the polyelectrolyte deposition of a negatively charged alginate solution (pH = 8 and a positively charged regenerated silk fibroin solution (pH = 2. Finally, the negatively charged regenerated silk fibroin solution (pH = 8 was used to assemble the outermost layer of the fabric so that the surface would be negatively charged. A stable structural transition was induced using 75% ethanol. The thickness and morphology were characterised using atomic force microscopy. The properties of the self-assembled silk fibroin fabric, such as the bursting strength, thermal stability and flushing stability, indicated that the fabric was stable. In addition, the cytocompatibility and haemocompatibility of the self-assembled silk fibroin fabrics were evaluated. The results indicated that the biocompatibility of the self-assembled multilayers was acceptable and that it improved markedly. In particular, after the self-assembly, the fabric was able to prevent platelet adhesion. Furthermore, other non-haemolytic biomaterials can be created through self-assembly of more than 1.5 bilayers, and we propose that self-assembled silk fibroin fabric may be an attractive candidate for anticoagulation applications and for promoting

  9. Silk reinforced with graphene or carbon nanotubes spun by spiders

    OpenAIRE

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

    2015-01-01

    Here, we report the production of silk incorporating graphene and carbon nanotubes directly by spider spinning, after spraying spiders with the corresponding aqueous dispersions. We observe a significant increment of the mechanical properties with respect to the pristine silk, in terms of fracture strength, Young's and toughness moduli. We measure a fracture strength up to 5.4 GPa, a Young's modulus up to 47.8 GPa and a toughness modulus up to 2.1 GPa, or 1567 J/g, which, to the best of our k...

  10. Untangling spider silk evolution with spidroin terminal domains

    Directory of Open Access Journals (Sweden)

    Garb Jessica E

    2010-08-01

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

  11. The Algorithm to Detect Color Gradation on Silk

    Directory of Open Access Journals (Sweden)

    Suyoto

    2012-03-01

    Full Text Available The process of silk dyeing with natural dye extracts will produce a certain color. Using extracts of wood, leaf and their combinations will give some color gradations. This paper aims to create a new algorithm which can help one, whose intention is to formulate the combination of coloring process to achieve the desired color through combining coloring materials on silk fabric. This algorithm will be expected to be able to formulate the combination of colors with more than 75 percent of accuracy. The natural dyes used were Ceriops candolleana arn wood for the red, Cudraina javanensis wood for the yellow, and indigofera leaf for the blue base color.

  12. Synthesis and characterization of spider silk calcite composite

    Directory of Open Access Journals (Sweden)

    Svetlana Dmitrović

    2016-03-01

    Full Text Available Spider silk poses excellent mechanical properties, tenacity and elasticity and it has been used as a template for calcite mineralization to improve load bearing strength of osteoconductive calcite. The samples were obtained by mimicking biomineralization for five days in order to follow formation and growth of calcite on the surface of spider silk. Crystal phase was detected by XRD and FTIR spectroscopy. Microstructure, crystal size and its morphology were studied by means of FESEM. After two days of processing, pure calcite phase was obtained, and a size of the formed crystals increased with prolongation of biomineralization.

  13. Folding behavior of four silks of giant honey bee reflects the evolutionary conservation of aculeate silk proteins.

    Science.gov (United States)

    Maitip, Jakkrawut; Trueman, Holly E; Kaehler, Benjamin D; Huttley, Gavin A; Chantawannakul, Panuwan; Sutherland, Tara D

    2015-04-01

    Multiple gene duplication events in the precursor of the Aculeata (bees, ants, hornets) gave rise to four silk genes. Whilst these homologs encode proteins with similar amino acid composition and coiled coil structure, the retention of all four homologs implies they each are important. In this study we identified, produced and characterized the four silk proteins from Apis dorsata, the giant Asian honeybee. The proteins were readily purified, allowing us to investigate the folding behavior of solutions of individual proteins in comparison to mixtures of all four proteins at concentrations where they assemble into their native coiled coil structure. In contrast to solutions of any one protein type, solutions of a mixture of the four proteins formed coiled coils that were stable against dilution and detergent denaturation. The results are consistent with the formation of a heteromeric coiled coil protein complex. The mechanism of silk protein coiled coil formation and evolution is discussed in light of these results. PMID:25712559

  14. Structure to function: Spider silk and human collagen

    Science.gov (United States)

    Rabotyagova, Olena S.

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

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

    Directory of Open Access Journals (Sweden)

    Ingi Agnarsson

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

  16. Where East Meets West: Highlights of Xinjiang Silk Road Artifacts

    Institute of Scientific and Technical Information of China (English)

    LiangFeng

    2003-01-01

    The mysterious ancient Silk Road, which stretched over 7,000 kilometers, linked different nations on the Asia-Europe continent for more than 2,000 years. On this trade route of historical significance, there is one place where four great ancient civilizations of the world, Chinese, Indian, Greek and Islamic, converged -- Xinjiang.

  17. Sericin diversity adds to the complexity of lepidopteran silk fibre

    Czech Academy of Sciences Publication Activity Database

    Sehnal, František; Žurovec, Michal; Kludkiewicz, B.

    Izmir : Entomological Society of Turkey , 2006. s. 97-97. [European Congress of Entomology /8./. 17.09.2006-22.09.2006, Izmir] R&D Projects: GA AV ČR IAA5007402 Institutional research plan: CEZ:AV0Z50070508 Keywords : silk fibre Subject RIV: CE - Biochemistry

  18. Teaching the Silk Road: A Journey of Pedagogical Discovery.

    Science.gov (United States)

    Andrea, A. J.; Mierse, William

    2002-01-01

    Describes a course for first-year college students that focuses on the Silk Road. Discusses the problems that occurs in such a course, types of resources used, basic strategies and tactics taken, and the focus on mapmaking in the beginning of the course. Includes an annotated bibliography. (CMK)

  19. Silk cocoon drying in forced convection type solar dryer

    International Nuclear Information System (INIS)

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

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

    NARCIS (Netherlands)

    Hoang Anh Tuan,

    2006-01-01

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

  1. Nederland loopt voorop met geconditioneerd telen (interview met Silke Hemming)

    NARCIS (Netherlands)

    Arkesteijn, M.; Hemming-Hoffmann, S.

    2007-01-01

    Sinds 1998 heeft Nederland ervaring met het telen in gesloten kassen en loopt daarmee voorop met geconditioneerd telen. Andere landen maken daarmee een voorzichtig begin. Silke Hemming, teamleider Tuinbouwtechnologie bij Wageningen UR Glastuinbouw, bezocht eind 2007 een congres over gesloten kassyst

  2. Relationships between physical properties and sequence in silkworm silks

    Science.gov (United States)

    Malay, Ali D.; Sato, Ryota; Yazawa, Kenjiro; Watanabe, Hiroe; Ifuku, Nao; Masunaga, Hiroyasu; Hikima, Takaaki; Guan, Juan; Mandal, Biman B.; Damrongsakkul, Siriporn; Numata, Keiji

    2016-06-01

    Silk has attracted widespread attention due to its superlative material properties and promising applications. However, the determinants behind the variations in material properties among different types of silk are not well understood. We analysed the physical properties of silk samples from a variety of silkmoth cocoons, including domesticated Bombyx mori varieties and several species from Saturniidae. Tensile deformation tests, thermal analyses, and investigations on crystalline structure and orientation of the fibres were performed. The results showed that saturniid silks produce more highly-defined structural transitions compared to B. mori, as seen in the yielding and strain hardening events during tensile deformation and in the changes observed during thermal analyses. These observations were analysed in terms of the constituent fibroin sequences, which in B. mori are predicted to produce heterogeneous structures, whereas the strictly modular repeats of the saturniid sequences are hypothesized to produce structures that respond in a concerted manner. Within saturniid fibroins, thermal stability was found to correlate with the abundance of poly-alanine residues, whereas differences in fibre extensibility can be related to varying ratios of GGX motifs versus bulky hydrophobic residues in the amorphous phase.

  3. Differential scanning fluorimetry illuminates silk feedstock stability and processability

    Czech Academy of Sciences Publication Activity Database

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

    2016-01-01

    Roč. 12, č. 1 (2016), s. 255-262. ISSN 1744-683X R&D Projects: GA MŠk(CZ) EE2.3.30.0029 Institutional support: RVO:61389013 Keywords : differential scanning fluorimetry * biomaterials * silk fibroin Subject RIV: CE - Biochemistry Impact factor: 4.029, year: 2014

  4. Identification and classification of silks using infrared spectroscopy.

    Science.gov (United States)

    Boulet-Audet, Maxime; Vollrath, Fritz; Holland, Chris

    2015-10-01

    Lepidopteran silks number in the thousands and display a vast diversity of structures, properties and industrial potential. To map this remarkable biochemical diversity, we present an identification and screening method based on the infrared spectra of native silk feedstock and cocoons. Multivariate analysis of over 1214 infrared spectra obtained from 35 species allowed us to group silks into distinct hierarchies and a classification that agrees well with current phylogenetic data and taxonomies. This approach also provides information on the relative content of sericin, calcium oxalate, phenolic compounds, poly-alanine and poly(alanine-glycine) β-sheets. It emerged that the domesticated mulberry silkmoth Bombyx mori represents an outlier compared with other silkmoth taxa in terms of spectral properties. Interestingly, Epiphora bauhiniae was found to contain the highest amount of β-sheets reported to date for any wild silkmoth. We conclude that our approach provides a new route to determine cocoon chemical composition and in turn a novel, biological as well as material, classification of silks. PMID:26347557

  5. The Political Economics of the New Silk Road

    Directory of Open Access Journals (Sweden)

    Sárvári Balázs

    2016-02-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2016-08-01

    The objective of the present study was to determine the feasibility and biocompatibility of a silk scaffold and a composite silk scaffold in terms of new tendon generation using a rabbit Achilles tendon model. The silk scaffold was constructed using a weaving machine, then soaked in a 1% collagen-hyaluronan (HA) solution and air-dried, whereas the composite silk scaffold was composed of a silk scaffold containing a lyophilized collagen-HA substrate. Tenocytes were cultured in vitro to compare cell populations in the two groups. The cellular densities on composite silk scaffolds were 40% higher on average than those on silk scaffolds in 30-day tenocyte cultures. The tendon scaffolds had implanted into Achilles tendon defects in 16 white New Zealand rabbits. Rabbits were randomly divided into the following three groups: group I, silk scaffold alone; group II, composite silk scaffold; and group III, composite silk scaffold wrapped by an amniotic membrane. Implants were harvested 2, 8, and 12 weeks post-implantation. Histological examinations were conducted using hematoxylin-eosin (H&E), Masson's trichrome, and by performing immunohistochemical staining for CD34. After 12 weeks, the three groups were distinguishable based on gross examination. The histological examination revealed more organized collagen fibrils in groups III, which showed a dense, parallel, linear organization of collagen bundles. CD34 staining revealed neoangiogenesis in groups III. The results of this research showed that collagen-HA substrates with amniotic membrane accelerate cellular migration and angiogenesis in neotendons. PMID:27188627

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

    Science.gov (United States)

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

    2016-01-01

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

  9. Nanoscale control of silica particle formation via silk-silica fusion proteins for bone regeneration.

    Science.gov (United States)

    Mieszawska, Aneta J; Nadkarni, Lauren D; Perry, Carole C; Kaplan, David L

    2010-10-26

    The biomimetic design of silk/silica fusion proteins was carried out, combining the self assembling domains of spider dragline silk (Nephila clavipes) and silaffin derived R5 peptide of Cylindrotheca fusiformis that is responsible for silica mineralization. Genetic engineering was used to generate the protein-based biomaterials incorporating the physical properties of both components. With genetic control over the nanodomain sizes and chemistry, as well as modification of synthetic conditions for silica formation, controlled mineralized silk films with different silica morphologies and distributions were successfully generated; generating 3D porous networks, clustered silica nanoparticles (SNPs), or single SNPs. Silk serves as the organic scaffolding to control the material stability and multiprocessing makes silk/silica biomaterials suitable for different tissue regenerative applications. The influence of these new silk-silica composite systems on osteogenesis was evaluated with human mesenchymal stem cells (hMSCs) subjected to osteogenic differentiation. hMSCs adhered, proliferated, and differentiated towards osteogenic lineages on the silk/silica films. The presence of the silica in the silk films influenced osteogenic gene expression, with the upregulation of alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col 1) markers. Evidence for early bone formation as calcium deposits was observed on silk films with silica. These results indicate the potential utility of these new silk/silica systems towards bone regeneration. PMID:20976116

  10. Conductive polymer combined silk fiber bundle for bioelectrical signal recording.

    Directory of Open Access Journals (Sweden)

    Shingo Tsukada

    Full Text Available Electrode materials for recording biomedical signals, such as electrocardiography (ECG, electroencephalography (EEG and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread, which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions.An electroconductive polyelectrolyte, poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate (PEDOT-PSS was electrochemically combined with silk thread made from natural Bombyx mori. The polymer composite 280 µm thread exhibited a conductivity of 0.00117 S/cm (which corresponds to a DC resistance of 2.62 Mohm/cm. The addition of glycerol to the PEDOT-PSS silk thread improved the conductivity to 0.102 S/cm (20.6 kohm/cm. The wettability of PEDOT-PSS was controlled with glycerol, which improved its durability in water and washing cycles. The glycerol treated PEDOT-PSS silk thread showed a tensile strength of 1000 cN in both wet and dry states. Without using any electrolytes, pastes or solutions, the thread directly collects electrical signals from living tissue and transmits them through metal cables. ECG, EEG, and sensory evoked potential (SEP signals were recorded from experimental animals by using this thread placed on the skin. PEDOT-PSS silk glycerol composite thread offers a new class of biocompatible electrodes in the field of biomedical and health promotion that does not induce stress in the subjects.

  11. Protective effect of silk lutein on ultraviolet B-irradiated human keratinocytes

    Directory of Open Access Journals (Sweden)

    Sutatip Pongcharoen

    2013-01-01

    Full Text Available Carotenoids are efficient antioxidants that are of great importance for human health. Lutein and zeaxanthin are carotinoids present in high concentrations in the human retina which are involved in the photoprotection of the human eye. Lutein may also protect the skin from ultraviolet (UV-induced damage. The present study investigated the protective effect of lutein extracted from yellow silk cocoons of Bombyx mori on human keratinocytes against UVB irradiation. A human keratinocyte cell line and primary human keratinocytes were used to investigate the UVB protection effects of silk lutein and plant lutein. Silk lutein showed no cytotoxicity to keratinocytes. Treatment with silk lutein prior to UVB irradiation enhanced cell viability and cell proliferation, and reduced cell apoptosis. The protective effects of silk lutein may be superior to those of plant lutein. Silk lutein may have a benefit for protection of keratinocytes against UVB-irradiation.

  12. Effect of residual sericin on the structural characteristics and properties of regenerated silk films.

    Science.gov (United States)

    Lee, Ji Hye; Song, Dae Woong; Park, Young Hwan; Um, In Chul

    2016-08-01

    Regenerated silk film has been increasingly attracting the research community's attention for biomedical applications due to its good biocompatibility and excellent cyto-compatibility. However, some limitations regarding its mechanical properties, such as brittleness, have restricted the use of silk films for industrial biomedical applications. In this study, regenerated silk films with different residual sericin content were prepared applying controlled degumming conditions to evaluate the effect of sericin content on the structure and properties of the films generated. When the residual sericin content increased to 0.6%, crystallinity index and breaking strength of silk films were increased. Above this value, these parameters then decreased. A 1.5 fold increase of silk film elongation properties was obtained when incorporating 16% sericin. Regardless of sericin content, all regenerated silk films showed excellent cyto-compatibility, comparable to the one obtained with tissue culture plates. PMID:27126168

  13. Nanoscale Control of Silks for Nanofibrous Scaffold Formation with Improved Porous Structure

    OpenAIRE

    Lin, Shasha; Lu, Guozhong; Liu, Shanshan; Bai, Shumeng; Liu, Xi; Lu, Qiang; Zuo, Baoqi; Kaplan, David L.; Zhu, Hesun

    2014-01-01

    Silk-based porous scaffolds have been used extensively in tissue engineering because of their excellent biocompatibility, tunable biodegradability and robust mechanical properties. Although many silk-based scaffolds have been prepared through freeze-drying, a challenge remains to effectively control porous structures during this process. In the present study silk fibroin with different nanostructures were self-assembled in aqueous solution by repeated drying-dissolving process and then used t...

  14. A modified method for inducing periodontitis in dogs using a silk-wire twisted ligature

    OpenAIRE

    Kim, Se Eun; Lee, Eui Ri; LEE, Yesran; Jeong, Manbok; Park, Young Woo; Ahn, Jae Sang; Ahn, Jeong Taek; SEO, Kangmoon

    2012-01-01

    This study was designed to assess the effectiveness of a modified silk ligature twisted with wire for inducing advanced periodontitis. Periodontitis was induced in five premolars and one molar of 20 healthy dogs over a 60-day period. The dogs were divided into four groups according to the ligature-inducing materials used: soft moistened food only, wire ligature (WL), silk ligature (SL) and twisted ligature with silk and wire (SWL). Periodontal indices were recorded, and dental radiographs wer...

  15. The Role of Silk in the Behaviour and Sociality of Spiders

    OpenAIRE

    Bertrand Krafft; Cookson, Laurie J.

    2012-01-01

    This article describes the links between the production of silk by spiders and their behaviour. Silk allows the spider to change its physical environment, which in turn leads to behavioural changes and impacts in the new environment. The feedback between silk and the animal producer can explain the architecture of spider webs and their adaptation to the environment, by referring only to stereotypic stimulus-response reactions without necessarily resorting to a “representation” by the animal o...

  16. The Performance of Silk Scaffolds in a Rat Model of Augmentation Cystoplasty

    OpenAIRE

    Seth, Abhishek; Chung, Yeun Goo; Gil, Eun Seok; Tu, Duong; Franck, Debra; Di Vizio, Dolores; Adam, Rosalyn M.; Kaplan, David L.; Estrada, Carlos R.; Mauney, Joshua R

    2013-01-01

    The diverse processing plasticity of silk-based biomaterials offers a versatile platform for understanding the impact of structural and mechanical matrix properties on bladder regenerative processes. Three distinct groups of 3-D matrices were fabricated from aqueous solutions of Bombyx mori silk fibroin either by a gel spinning technique (GS1 and GS2 groups) or a solvent-casting/salt-leaching method in combination with silk film casting (FF group). SEM analyses revealed that GS1 matrices cons...

  17. Differential Scanning Fluorimetry provides high throughput data on silk protein transitions

    OpenAIRE

    Vollrath, Fritz; Hawkins, Nick; Porter, David; Holland, Chris; Boulet-Audet, Maxime

    2014-01-01

    Here we present a set of measurements using Differential Scanning Fluorimetry (DSF) as an inexpensive, high throughput screening method to investigate the folding of silk protein molecules as they abandon their first native melt conformation, dehydrate and denature into their final solid filament conformation. Our first data and analyses comparing silks from spiders, mulberry and wild silkworms as well as reconstituted ‘silk' fibroin show that DSF can provide valuable insights into details of...

  18. China Silk Commodities:Exports Down by 5.05% in Q1

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to statistics promulgated by China Customs, total export value of silk commodities was 1.776 billion USD from January to March of 2007,down by 5.05% compared with the same period of last year.Among the export commodities,pure silk commodities export was 803 million USD,a decrease of 10.17% year-on-year;man-made silk commodities export was 972 million USD,descended by 0.35%.

  19. China Silk Commodities: Exports Down by 5.05% in Q1

    Institute of Scientific and Technical Information of China (English)

    Zhang Yan

    2007-01-01

    @@ According to statistics promulgated by China Customs, total export value of silk commodities was 1.776 billion USD from January to March of 2007, down by 5.05% compared with the same period of last year. Among the export commodities, pure silk commodities export was 803 million USD, a decrease of 10.17% year-on-year; man-made silk commodities export was 972 million USD, descended by 0.35%.

  20. Silk Reeling and Health: Life Style and Quality of Life of Workers

    OpenAIRE

    Anand Inbanathan; Om Prakash

    2003-01-01

    Silk reeling is an activity where mostly people of little education and skill learn reeling skills while being employed in the reeling units. Reeling is carried out in an environment of persistent air pollution. Workers allergic to the silk allergen (sericin and pupal allergens) suffer from respiratory problems and asthma, i.e. of occupational asthma. Non-occupational asthma victims may suffer exacerbations due to irritant effects of the silk occupation. Work-aggravated asthma follows mainly ...

  1. ELECTROPHORETIC SEPARATION AND COMPARATIVE ANALYSIS OF SILK GLAND PROTEINS FROM BOMBYX AND PHILOSAMIA

    OpenAIRE

    Muzafar A Bhat, Punyavathi and Manjunatha H Boregowda*

    2014-01-01

    A comparative analysis of protein extracted from different regions of silk glands in the Bombyx mori L. and Philosamia ricini Hutt was performed employing single-dimensional-electrophoresis technique. Notably, a protein extracted directly from the lumen of the middle silk gland yielded two discrete protein bands with molecular mass of 325 and 26 kDa representing fibroin heavy (H) and low (L) chains than whole silk gland of B. mori. Contrastingly, such differentiation in protein separation cou...

  2. Nutritional compositions and antioxidative capacity of the silk obtained from immature and mature corn

    Directory of Open Access Journals (Sweden)

    Nurhanan Abdul Rahman

    2014-04-01

    Full Text Available The silks of immature and mature corn were evaluated for their variations in nutritional compositions, mineral content and antioxidant capacity. Both immature and mature silks were good source of nutritional compositions. Immature silks contained significantly higher moisture (89.31% (fresh basis, lipid (1.27% and protein (12.96% content than the mature silk. Mature silks contained higher composition of ash (5.51%, carbohydrate (29.74% and total dietary fiber (51.25 g/100 g, than the immature silk, but the difference was not significant. In mineral determination, immature silk was rich source of Ca (1087.08 μg/g, Mg (1219.17 μg/g, Cu (5.60 μg/g and Zn (46.37 μg/g than the mature silks. In contrast, other minerals such as K (35671.67 μg/g, Na (266.67 μg/g, Fe (4.50 μg/g and Mn (35.57 μg/g were found higher in the mature silk. The silks were extracted with ethyl acetate, ethanol and water using the Soxhlet extraction method to determine the polyphenol and ABTS radical scavenging capacity. From this study, the highest content of total polyphenol of immature silks was exhibited by ethanol extract (92.21 mg GAE/g while water extract (64.22 mg GAE/g had the highest polyphenol content among mature silk extracts. Total flavonoid content of both immature and mature silks was higher in the water extract at 8.40 mg CAE/g and 2.31 mg CAE/g, respectively. In the ABTS free radical assay method, all immature silk extracts had higher percentage of inhibition compared to the mature silks. Among all three crude extracts, the ethanol extract of immature (EC50 = 0.478 mg/ml and mature silk (EC50 = 0.799 mg/ml exhibited the strongest antioxidant capacity followed by the water and ethyl acetate extract.

  3. Identification, recombinant production and structural characterization of four silk proteins from the Asiatic honeybee Apis cerana.

    Science.gov (United States)

    Shi, Jiahai; Lua, Shixiong; Du, Ning; Liu, Xiangyang; Song, Jianxing

    2008-06-01

    Unlike silkworm and spider silks assembled from very large and repetitive fibrous proteins, the bee and ant silks were recently demonstrated to consist of four small and non-repetitive coiled-coil proteins. The design principle for this silk family remains largely unknown and so far no structural study is available on them in solution. The present study aimed to identify, express and characterize the Asiatic honeybee silk proteins using DLS, CD and NMR spectroscopy. Consequently, (1) four silk proteins are identified, with approximately 6, 10, 9 and 8% variations, respectively, from their European honeybee homologs. Strikingly, their recombinant forms can be produced in Escherichia coil with yields of 10-60 mg/l. (2) Despite containing approximately 65% coiled-coil sequences, four proteins have very low alpha-helix (9-27%) but unusually high random coil (45-56%) contents. Surprisingly, beta-sheet is also detected in four silk proteins (26-35%), implying the possible presence of beta-sheet in the bee and ant silks. (3) Four proteins lacking of the tight tertiary packing appear capable of interacting with each other weakly but this interaction triggers no significant formation of the tight tertiary packing. The study not only implies the promising potential to produce recombinant honeybee silk proteins for the development of various biomaterials; but also provides the first structural insight into the molecular mechanism underlying the formation of the coiled-coil silks. PMID:18394700

  4. Radiation processing of silk protein (Bilateral research cooperation OAEP and JAERI. December 1998 - December 2002)

    International Nuclear Information System (INIS)

    Thailand's production of silk, about 1,200 ton per year, also gives about 10% of silk waste which is expected to be recycled into new material (non-textile application) and to avoid environmental pollution. For this purpose, cooperative program 'radiation processing of silk protein' was conducted between OAEP (Thailand) and JAERI. Among the results already obtained are: radiation degradation of silk protein (fibroin) with gamma rays at 160 kGy, production of fine silk milled powder (<90 microns) by electron beam irradiation at 250-1000 kGy (dry method) using electron accelerator (1 MeV, 1 mA), use of antioxidant effect of silk protein on lipid peroxidation and antibacterial activity of irradiated silk protein powder, and wound dressing hydrogel mixed with silk protein and use of antibacterial activity of cross-linked silk protein/PVA hydrogel. Other topics of interest are gamma irradiation of anionic natural polymer solution for use as latex protein scavenger and gamma radiation degradation of chitosan for use as plant growth promoter and fungicide. (S. Ohno)

  5. Inner ear delivery of dexamethasone using injectable silk-polyethylene glycol (PEG) hydrogel.

    Science.gov (United States)

    Yu, Dehong; Sun, Changling; Zheng, Zhaozhu; Wang, Xueling; Chen, Dongye; Wu, Hao; Wang, Xiaoqin; Shi, Fuxin

    2016-04-30

    Minimally invasive delivery and sustained release of therapeutics to the inner ear are of importance to the medical treatment of inner ear disease. In this study, the injectable silk fibroin-polyethylene glycol (Silk-PEG) hydrogel was investigated as a drug delivery carrier to deliver poorly soluble micronized dexamethasone (mDEX) to the inner ear of guinea pigs. Encapsulation of mDEX with a loading up to 5% (w/v) did not significantly change the silk gelation time, and mDEX were evenly distributed in the PEG-Silk hydrogel as visualized by SEM. The loading of mDEX in Silk-PEG hydrogel largely influenced in vitro drug release kinetics. The optimized Silk-PEG-mDEX hydrogel (2.5% w/v loading, in situ-forming,10μl) was administered directly onto the round window membrane of guinea pigs. The DEX concentration in perilymph maintained above 100ng/ml for at least 10 days for the Silk-PEG formulation while less than 12h for the control sample of free mDEX. Minimal systemic exposure was achieved with low DEX concentrations (scala taympani. The Silk-PEG hydrogel completely degraded in 21 days. Thus, the injectable PEG-Silk hydrogel is an effective and safe vehicle for inner ear delivery and sustained release of glucocorticoid. PMID:26972377

  6. Biobased silver nanocolloid coating on silk fibers for prevention of post-surgical wound infections

    Directory of Open Access Journals (Sweden)

    Dhas SP

    2015-10-01

    Full Text Available Sindhu Priya Dhas, Suruthi Anbarasan, Amitava Mukherjee, Natarajan Chandrasekaran Center for Nanobiotechnology, VIT University, Vellore, India Abstract: Bombyx mori silk fibers are an important biomaterial and are used in surgical sutures due to their remarkable biocompatibility. The major drawback to the application of biomaterials is the risk of bacterial invasion, leading to clinical complications. We have developed an easy and cost-effective method for fabrication of antibacterial silk fibers loaded with silver nanoparticles (AgNPs by an in situ and ex situ process using an aqueous extract of Rhizophora apiculata leaf. Scanning electron microscopy revealed that well dispersed nanoparticles impregnated the silk fibers both in situ and ex situ. The crystalline nature of the AgNPs in the silk fibers was demonstrated by X-ray diffraction. The thermal and mechanical properties of the silk fibers were enhanced after they were impregnated with AgNPs. The silver-coated silk fibers fabricated by the in situ and ex situ method exhibited more than 90% inhibition against Pseudomonas aeruginosa and Staphylococcus aureus. Silk fibers doped with AgNPs were found to be biocompatible with 3T3 fibroblasts. The results obtained represent an important advance towards the clinical application of biocompatible AgNP-loaded silk fibers for prevention of surgical wound infections. Keywords: silk fibers, silver nanoparticles, antibacterial activity, wound infections, cytotoxicity, 3T3 fibroblast cells

  7. Aqueous multiphoton lithography with multifunctional silk-centred bio-resists

    Science.gov (United States)

    Sun, Yun-Lu; Li, Qi; Sun, Si-Ming; Huang, Jing-Chun; Zheng, Bo-Yuan; Chen, Qi-Dai; Shao, Zheng-Zhong; Sun, Hong-Bo

    2015-10-01

    Silk and silk fibroin, the biomaterial from nature, nowadays are being widely utilized in many cutting-edge micro/nanodevices/systems via advanced micro/nanofabrication techniques. Herein, for the first time to our knowledge, we report aqueous multiphoton lithography of diversiform-regenerated-silk-fibroin-centric inks using noncontact and maskless femtosecond laser direct writing (FsLDW). Initially, silk fibroin was FsLDW-crosslinked into arbitrary two/three-dimensional micro/nanostructures with good elastic properties merely using proper photosensitizers. More interestingly, silk/metal composite micro/nanodevices with multidimension-controllable metal content can be FsLDW-customized through laser-induced simultaneous fibroin oxidation/crosslinking and metal photoreduction using the simplest silk/Ag+ or silk/[AuCl4]- aqueous resists. Noticeably, during FsLDW, fibroin functions as biological reductant and matrix, while metal ions act as the oxidant. A FsLDW-fabricated prototyping silk/Ag microelectrode exhibited 104-Ω-1 m-1-scale adjustable electric conductivity. This work not only provides a powerful development to silk micro/nanoprocessing techniques but also creates a novel way to fabricate multifunctional metal/biomacromolecule complex micro/nanodevices for applications such as micro/nanoscale mechanical and electrical bioengineering and biosystems.

  8. SILK ROAD DISEASE: FROM LEGENDS TO THE 21st CENTURY

    Directory of Open Access Journals (Sweden)

    Z. S. Alekberova

    2015-03-01

    Full Text Available The paper considers the historical and geographical aspects of Behcet’s disease (BD. As is known, the geographical distribution of this disease is associated with the ancient caravan route called the Silk Road: it was in these areas along which the latter once ran there have been predominantly cases of BD so far. There are discrepancies in the literature regarding whether the Silk Road was across the North Caucasus, along the coast of the Caspian Sea in particular. In support of this conjecture, there is interesting evidence: stone-cutting images that have been retained on the houses of the Dagestani settlement of Kubachi. All give an answer why the natives of the North Caucasus constitute one-fourth of the total number of BD patients followed up at the V.A. Nasonova Research Institute of Rheumatology 

  9. Diffraction from the beta-sheet crystallites in spider silk.

    Science.gov (United States)

    Ulrich, S; Glišović, A; Salditt, T; Zippelius, A

    2008-11-01

    We analyze the wide-angle X-ray scattering from oriented spider silk fibers in terms of a quantitative scattering model, including both structural and statistical parameters of the beta-sheet crystallites of spider silk in the amorphous matrix. The model is based on kinematic scattering theory and allows for rather general correlations of the positional and orientational degrees of freedom, including the crystallite's size, composition and dimension of the unit cell. The model is evaluated numerically and compared to experimental scattering intensities allowing us to extract the geometric and statistical parameters. We show explicitly that for the experimentally found mosaicity (width of the orientational distribution) intercrystallite effects are negligible and the data can be analyzed in terms of single-crystallite scattering, as is usually assumed in the literature. PMID:18843512

  10. Biomimetic spinning of silk fibers and in situ cell encapsulation.

    Science.gov (United States)

    Cheng, Jie; Park, DoYeun; Jun, Yesl; Lee, JaeSeo; Hyun, Jinho; Lee, Sang-Hoon

    2016-07-01

    In situ embedding of sensitive materials (e.g., cells and proteins) in silk fibers without damage presents a significant challenge due to the lack of mild and efficient methods. Here, we report the development of a microfluidic chip-based method for preparation of meter-long silk fibroin (SF) hydrogel fibers by mimicking the silkworm-spinning process. For the spinning of SF fibers, alginate was used as a sericin-like material to induce SF phase separation and entrap liquid SFs, making it possible to shape the outline of SF-based fibers under mild physicochemical conditions. L929 fibroblasts were encapsulated in the fibric hydrogel and displayed excellent viability. Cell-laden SF fibric hydrogels prepared using our method offer a new type of SF-based biomedical device with potential utility in biomedicine. PMID:27296229

  11. The molecular structures of major ampullate silk proteins of the wasp spider, Argiope bruennichi: a second blueprint for synthesizing de novo silk.

    Science.gov (United States)

    Zhang, Yang; Zhao, Ai-Chun; Sima, Yang-Hu; Lu, Cheng; Xiang, Zhong-Huai; Nakagaki, Masao

    2013-03-01

    The dragline silk of orb-weaving spiders possesses extremely high tensile strength and elasticity. To date, full-length sequences of only two genes encoding major ampullate silk protein (MaSp) in Latrodectus hesperus have been determined. In order to further understand this gene family, we utilized in this study a variety of strategies to isolate full-length MaSp1 and MaSp2 cDNAs in the wasp spider Argiope bruennichi. A. bruennichi MaSp1 and MaSp2 are primarily composed of remarkably homogeneous ensemble repeats containing several complex motifs, and both have highly conserved C-termini and N-termini. Two novel amino acid motifs, GGF and SGR, were found in MaSp1 and MaSp2, respectively. Amino acid composition analysis of silk, luminal contents and predicted sequences indicates that MaSp1 and MaSp2 are two major components of major ampullate glands and that the ratio of MaSp1 to MaSp2 is approximately 3:2 in dragline silk. Furthermore, both the MaSp1:MaSp2 ratio and the conserved termini are closely linked with the production of high quality synthetic fibers. Our results make an important contribution to our understanding of major ampullate silk protein structure and provide a second blueprint for creating new composite silk which mimics natural spider dragline silk. PMID:23262065

  12. Nanolayer Biomaterial Coatings of Silk Fibroin for Controlled Release

    OpenAIRE

    Wang, Xianyan; Hu, Xiao; Daley, Andrea; Rabotyagova, Olena; Cebe, Peggy; Kaplan, David L.

    2007-01-01

    An all-aqueous, stepwise deposition process with silk fibroin protein for the assembly of nanoscale layered controlled release coatings was exploited. Model compounds, Rhodamine B, Even Blue and Azoalbumin, representing small molecule drugs and therapeutically relevant proteins were incorporated in the nanocoating process and their loading and release behavior was quantified. In addition, the structure and morphology of the coatings were characterized. Release studies in vitro showed that con...

  13. An Understanding of The Maritime Silk Road International Strategic Importance

    Institute of Scientific and Technical Information of China (English)

    Lin; Hongyu

    2015-01-01

    "The Maritime Silk Road"conception has a very significant international strategic importance,and to China,will certainly play a great role in promoting its economic development,which is only on the surface,and an in-depth reading is that it is a top-level strategic design,whose strategic role with the passage of time will be enlarged.In his address to Indonesian National Assembly in October 2013,President Xi

  14. Overcoming dormancy in seeds of cotton-silk tree

    OpenAIRE

    Irinaldo Lima do Nascimento

    2012-01-01

    Cotton-silk tree Ceiba glaziovii (kuntze) k. Schu belongs to family Bombacaceas and is locally known as barriguda. It is widely used in landscaping and reforestation, neverdeless seed dormancy affects reproduction in this species. The objective of this study was to evaluate the effectiveness of different methods to overcome dormancy in the germination process. Treatments included mechanical scarification with 85-grit sandpaper, chemical scarification with concentrated sulfuric acid for 5, 10,...

  15. Preparation and characterization of silk fibroin/HPMC blend film

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, G. Rajesha [Department of Physics, Govt. First Grade College Hiriadka, Udupi - 576113 (India); Kumar, R. Madhu; Rao, B. Lakshmeesha; Asha, S.; Sangappa, E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore - 574199 (India)

    2015-06-24

    In this work, the structural and mechanical stability of silk fibroin/Hydroxypropylmethyl cellulose (SF-HPMC) blend films were characterized by X-ray diffraction (XRD) and Universal Testing Machine (UTM). The results indicate that with the introduction of HPMC, the interactions between SF and HPMC results in improved crystallite size and increase in mechanical properties. The blend film obtained is more flexible compared to pure SF film.

  16. Silk fibroin gelation via non-solvent induced phase separation

    Czech Academy of Sciences Publication Activity Database

    Kasoju, Naresh; Hawkins, N.; Pop-Georgievski, Ognen; Kubies, Dana; Vollrath, F.

    2016-01-01

    Roč. 4, č. 3 (2016), s. 460-473. ISSN 2047-4830 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : silk fibroin * non-solvent induced phase separation * desolvation Subject RIV: CE - Biochemistry Impact factor: 3.831, year: 2014

  17. Damage, Self-Healing, and Hysteresis in Spider Silks

    OpenAIRE

    De Tommasi, D.; Puglisi, G.; Saccomandi, G.

    2010-01-01

    In this article, we propose a microstructure-based continuum model to describe the material behavior of spider silks. We suppose that the material is composed of a soft fraction with entropic elasticity and a hard, damageable fraction. The hard fraction models the presence of stiffer, crystal-rich, oriented regions and accounts for the effect of softening induced by the breaking of hydrogen bonds. To describe the observed presence of crystals with different size, composition, and orientation,...

  18. Silk Fibroin as Edible Coating for Perishable Food Preservation

    OpenAIRE

    B. Marelli; M. A. Brenckle; Kaplan, D. L.; Omenetto, F. G.

    2016-01-01

    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-proc...

  19. Spray drying as a method of producing silk sericin powders

    OpenAIRE

    G. Genç; G. Narin; O. Bayraktar

    2009-01-01

    Purpose: The purpose of paper is to analyse Spray drying as a method of producing silk sericin powders.Design/methodology/approach: Aqueous sericin solutions were used as raw material for the production of dry powders using a lab-scale spray dryer. A linear regression analysis of agglomeration was employed, in addition to experimental designs at two levels with three factors for the analysis of three responses: moisture content, particle type and agglomeration degree. The process factors were...

  20. Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording

    OpenAIRE

    Shingo Tsukada; Hiroshi Nakashima; Keiichi Torimitsu

    2012-01-01

    Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in bot...

  1. The effect of ageing on the mechanical properties of the silk of the bridge spider Larinioides cornutus (Clerck, 1757)

    OpenAIRE

    Emiliano Lepore; Marco Isaia; Stefano Mammola; Nicola Pugno

    2016-01-01

    Spider silk is regarded as one of the best natural polymer fibers especially in terms of low density, high tensile strength and high elongation until breaking. Since only a few bio-engineering studies have been focused on spider silk ageing, we conducted nano-tensile tests on the vertical naturally spun silk fibers of the bridge spider Larinioides cornutus (Clerck, 1757) (Arachnida, Araneae) to evaluate changes in the mechanical properties of the silk (ultimate stress and strain, Young’s modu...

  2. Formulation of Biologically-Inspired Silk-Based Drug Carriers for Pulmonary Delivery Targeted for Lung Cancer

    OpenAIRE

    Sally Yunsun Kim; Deboki Naskar; Kundu, Subhas C.; Bishop, David P.; Doble, Philip A.; Boddy, Alan V.; Hak-Kim Chan; Ivan B. Wall; Wojciech Chrzanowski

    2015-01-01

    The benefits of using silk fibroin, a major protein in silk, are widely established in many biomedical applications including tissue regeneration, bioactive coating and in vitro tissue models. The properties of silk such as biocompatibility and controlled degradation are utilized in this study to formulate for the first time as carriers for pulmonary drug delivery. Silk fibroin particles are spray dried or spray-freeze-dried to enable the delivery to the airways via dry powder inhalers. The a...

  3. Printing of stretchable silk membranes for strain measurements.

    Science.gov (United States)

    Ling, Shengjie; Zhang, Qiang; Kaplan, David L; Omenetto, Fiorenzo; Buehler, Markus J; Qin, Zhao

    2016-07-01

    Quantifying the deformation of biological tissues under mechanical loading is crucial to understand its biomechanical response in physiological conditions and important for designing materials and treatments for biomedical applications. However, strain measurements for biological tissues subjected to large deformations and humid environments are challenging for conventional methods due to several limitations such as strain range, boundary conditions, surface bonding and biocompatibility. Here we propose the use of silk solutions and printing to synthesize prototype strain gauges for large strain measurements in biological tissues. The study shows that silk-based strain gauges can be stretched up to 1300% without failure, which is more than two orders of magnitude larger than conventional strain gauges, and the mechanics can be tuned by adjusting ion content. We demonstrate that the printing approach can accurately provide well bonded fluorescent features on the silk membranes using designs which can accurately measure strain in the membrane. The results show that these new strain gauges measure large deformations in the materials by eliminating the effects of sliding from the boundaries, making the measurements more accurate than direct outputs from tensile machines. PMID:27241909

  4. Thermal Properties of Silk Fibroin Using Fast Scanning Calorimetry

    Science.gov (United States)

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

    We performed fast scanning chip-based calorimetry of silk protein using the Mettler Flash DSC1. We suggest the methodology by which to obtain quantitative information on the very first scan to high temperature, including the melting endotherm of the beta pleated sheets. For proteins, this first scan is the most important one, because the crystalline secondary structural features, the beta pleated sheets, melt after the first heating and cannot be thermally reintroduced. To obtain high quality data, the samples must be treated to drying and enthalpy relaxation sequences. The heat flow rates in heating and cooling must be corrected for asymmetric heat loses. We evaluate methods to obtain an estimate of the sample mass, finally choosing internal calibration using the known heat capacity increment at the glass transition. We report that even heating at rates of 2000 K/s, thermal degradation of silk cannot be totally avoided, though it can be minimized. Using a set of nineteen samples, we successfully determine the liquid state heat capacity of silk as: Cpliquid (T) = (1.98 +0.06) J/gK + T (6.82 +1.4) x10-4 J/gK2. Methods for estimation of the sample mass will be presented and compared. National Science Foundation, Polymers Program DMR-1206010; DAAD; Tufts Faculty Supported Leave.

  5. Development and characterization of silk fibroin coated quantum dots

    Science.gov (United States)

    Nathwani, B. B.; Needham, C.; Mathur, A. B.; Meissner, K. E.

    2008-02-01

    Recent progress in the field of semiconductor nanocrystals or Quantum Dots (QDs) has seen them find wider acceptance as a tool in biomedical research labs. As produced, high quality QDs, synthesized by high temperature organometallic synthesis, are coated with a hydrophobic ligand. Therefore, they must be further processed to be soluble in water and to be made biocompatible. To accomplish this, the QDs are generally coated with a synthetic polymer (eg. block copolymers) or the hydrophobic surface ligands exchanged with hydrophilic material (eg. thiols). Advances in this area have enabled the QDs to experience a smooth transition from being simple inorganic fluorophores to being smart sensors, which can identify specific cell marker proteins and help in diagnosis of diseases such as cancer. In order to improve the biocompatibility and utility of the QDs, we report the development of a procedure to coat QDs with silk fibroin, a fibrous crystalline protein extracted from Bombyx Mori silkworm. Following the coating process, we characterize the size, quantum yield and two-photon absorption cross section of the silk coated QDs. Additionally, the results of biocompatibility studies carried out to compare the properties of these QD-silks with conventional QDs are presented. These natural polymer coatings on QDs could enhance the intracellular delivery and enable the use of these nanocrystals as an imaging tool for studying subcellular machinery at the molecular level.

  6. Study on antibacterial activity of hydrogel from irradiated silk protein

    International Nuclear Information System (INIS)

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N2 atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  7. Study on antibacterial activity of hydrogel from irradiated silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Bunnak, J.; Chaisupakitsin, M. [King Mongkut' s Institute of Technology Lardkrabang, Bangkok (Thailand)

    2001-03-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N{sub 2} atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  8. Ultrathin Free-Standing Bombyx mori Silk Nanofibril Membranes.

    Science.gov (United States)

    Ling, Shengjie; Jin, Kai; Kaplan, David L; Buehler, Markus J

    2016-06-01

    We report a new ultrathin filtration membrane prepared from silk nanofibrils (SNFs), directly exfoliated from natural Bombyx mori silk fibers to retain structure and physical properties. These membranes can be prepared with a thickness down to 40 nm with a narrow distribution of pore sizes ranging from 8 to 12 nm. Typically, 40 nm thick membranes prepared from SNFs have pure water fluxes of 13 000 L h(-1) m(-2) bar(-1), more than 1000 times higher than most commercial ultrathin filtration membranes and comparable with the highest water flux reported previously. The commercial membranes are commonly prepared from polysulfone, poly(ether sulfone), and polyamide. The SNF-based ultrathin membranes exhibit efficient separation for dyes, proteins, and colloids of nanoparticles with at least a 64% rejection of Rhodamine B. This broad-spectrum filtration membrane would have potential utility in applications such as wastewater treatment, nanotechnology, food industry, and life sciences in part due to the protein-based membrane polymer (silk), combined with the robust mechanical and separation performance features. PMID:27076389

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

    Directory of Open Access Journals (Sweden)

    Liangjun Zhu

    2012-06-01

    Full Text Available In order to use a simple and ecofriendly method to prepare porous silk scaffolds, aqueous silk fibroin solution (ASF was extracted from silk gland of 7-day-old fifth instar larvae of Bombyx mori (B. mori. SDS-page analysis indicated that the obtained fibroin had a molecular weight higher than 200 kDa. The fabrication of porous scaffolds from ASF was achieved by using the freeze-drying method. The pore of porous scaffolds is homogenous and tends to become smaller with an increase in the concentration of ASF. Conversely, the porosity is decreased. The porous scaffolds show impressive compressive strength which can be as high as 6.9 ± 0.4 MPa. Furthermore, ASF has high cell adhesion and growth activity. It also exhibits high ALP activity. This implies that porous scaffolds prepared from ASF have biocompatibility. Therefore, the porous scaffolds prepared in this study have potential application in tissue engineering due to the impressive compressive strength and biocompatibility.

  10. 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.

  11. Focal therapy of neuroblastoma using silk films to deliver kinase and chemotherapeutic agents in vivo.

    Science.gov (United States)

    Seib, F Philipp; Coburn, Jeannine; Konrad, Ilona; Klebanov, Nikolai; Jones, Gregory T; Blackwood, Brian; Charest, Alain; Kaplan, David L; Chiu, Bill

    2015-07-01

    Current methods for treatment of high-risk neuroblastoma patients include surgical intervention, in addition to systemic chemotherapy. However, only limited therapeutic tools are available to pediatric surgeons involved in neuroblastoma care, so the development of intraoperative treatment modalities is highly desirable. This study presents a silk film library generated for focal therapy of neuroblastoma; these films were loaded with either the chemotherapeutic agent doxorubicin or the targeted drug crizotinib. Drug release kinetics from the silk films were fine-tuned by changing the amount and physical crosslinking of silk; doxorubicin loaded films were further refined by applying a gold nanocoating. Doxorubicin-loaded, physically crosslinked silk films showed the best in vitro activity and superior in vivo activity in orthotopic neuroblastoma studies when compared to the doxorubicin-equivalent dose administered intravenously. Silk films were also suitable for delivery of the targeted drug crizotinib, as crizotinib-loaded silk films showed an extended release profile and an improved response both in vitro and in vivo when compared to freely diffusible crizotinib. These findings, when combined with prior in vivo data on silk, support a viable future for silk-based anticancer drug delivery systems. PMID:25861948

  12. Biobased silver nanocolloid coating on silk fibers for prevention of post-surgical wound infections

    Science.gov (United States)

    Dhas, Sindhu Priya; Anbarasan, Suruthi; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2015-01-01

    Bombyx mori silk fibers are an important biomaterial and are used in surgical sutures due to their remarkable biocompatibility. The major drawback to the application of biomaterials is the risk of bacterial invasion, leading to clinical complications. We have developed an easy and cost-effective method for fabrication of antibacterial silk fibers loaded with silver nanoparticles (AgNPs) by an in situ and ex situ process using an aqueous extract of Rhizophora apiculata leaf. Scanning electron microscopy revealed that well dispersed nanoparticles impregnated the silk fibers both in situ and ex situ. The crystalline nature of the AgNPs in the silk fibers was demonstrated by X-ray diffraction. The thermal and mechanical properties of the silk fibers were enhanced after they were impregnated with AgNPs. The silver-coated silk fibers fabricated by the in situ and ex situ method exhibited more than 90% inhibition against Pseudomonas aeruginosa and Staphylococcus aureus. Silk fibers doped with AgNPs were found to be biocompatible with 3T3 fibroblasts. The results obtained represent an important advance towards the clinical application of biocompatible AgNP-loaded silk fibers for prevention of surgical wound infections. PMID:26491317

  13. CLASSING APPROACH TO ANALYZING THE INVESTMENT SPACE OF SILK INDUSTRY OF UZBEKISTAN

    OpenAIRE

    Madjidov, Shakhrukh; Ibragimova, Sabokhat

    2015-01-01

    In the article the results of verification were brought which were dedicated for cluster approach and analyzing the investment space of silk industry of Uzbekistan. In particular the purpose of investment’s direction to the main capital of silk industry in corresponding class while proceeding from closeness to manual forces and raw material resources.

  14. Preparation and characterization of regenerated fiber from the aqueous solution of Bombyx mori cocoon silk fibroin

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhenghua [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Department of Application Engineering, ZheJiang Vocational College of Economic and Trade, HangZhou, ZheJiang 310018 (China); Imada, Takuzo [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Asakura, Tetsuo, E-mail: asakura@cc.tuat.ac.jp [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2009-10-15

    The regenerated silk fibers with high strength and high biodegradability were prepared from the aqueous solution of Bombyx mori silk fibroin from cocoons with wet spinning method. Although the tensile strength of the regenerated silk fibroin fiber, 210 MPa is still half of the strength of native silk fiber, the diameter of the fiber is about 100 {mu}m which is suitable for monofilament of suture together with high biodegradability. The high concentration (30%, w/v) of the aqueous solution of the silk fibroin which corresponds to the high concentration in the middle silkgland of silkworm was obtained. This was performed by adjusting the pH of the aqueous solution to 10.4 which corresponds to pK{sub a} value of the OH group of Tyr residues in the silk fibroin. The mixed solvent, methanol/acetic acid (7:3 in volume ratio) was used as coagulant solvent for preparing the regenerated fiber. The structural change of silk fibroin fiber by stretching was monitored with both {sup 13}C solid state NMR and X-ray diffraction methods, indicating that the high strength of the fiber is related with the long-range orientation of the silk fibroin chain with {beta}-sheet structure.

  15. Preparation and characterization of regenerated fiber from the aqueous solution of Bombyx mori cocoon silk fibroin

    International Nuclear Information System (INIS)

    The regenerated silk fibers with high strength and high biodegradability were prepared from the aqueous solution of Bombyx mori silk fibroin from cocoons with wet spinning method. Although the tensile strength of the regenerated silk fibroin fiber, 210 MPa is still half of the strength of native silk fiber, the diameter of the fiber is about 100 μm which is suitable for monofilament of suture together with high biodegradability. The high concentration (30%, w/v) of the aqueous solution of the silk fibroin which corresponds to the high concentration in the middle silkgland of silkworm was obtained. This was performed by adjusting the pH of the aqueous solution to 10.4 which corresponds to pKa value of the OH group of Tyr residues in the silk fibroin. The mixed solvent, methanol/acetic acid (7:3 in volume ratio) was used as coagulant solvent for preparing the regenerated fiber. The structural change of silk fibroin fiber by stretching was monitored with both 13C solid state NMR and X-ray diffraction methods, indicating that the high strength of the fiber is related with the long-range orientation of the silk fibroin chain with β-sheet structure.

  16. Development Strategy of Striving Nature Silk in Kabupaten Sukabumi, Propinsi Jawa Barat

    Directory of Open Access Journals (Sweden)

    Nurheni Wijayanto

    2012-09-01

    Full Text Available 800x600 The striving of nature silk in Kabupaten Sukabumi keeps decreasing whereas, market opportunity and potential for nature is good, for this time being. For knowing development strategic of striving nature silk correctly, it need to be done an aprroachment system of replacement SWOT analysis  (strategis analysis and ISM (interpretative Structural Modelling technique (structural analysis. This research will identify internal and external factor and produce structural models. The most powerful factor that influence the striving of nature silk is nature condition (climate, soil and topography.  The weakness factor are limited capital and access.  As opportunity element factor and treatment of cocoon needs still high and germ and disease of murbei leaves also silk worm. Prosperity of nature silk worm influence a lot of society sector especially farmer.  In way to make it success needs very qualified human resources, an expert on this work and good management.  Hoped with fulfilled need, will solved a lot of obstructions one of them is limited capital and access.  The purpose of this program as good as possible is for increasing nature silk work.  Involved all sorts of institution to realize this aim will be need, one of them is Forestry Department which will decide fact in striving of nature silk. Keyword : nature silk, strategis analysis, structural analysis, and development strategy. Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4

  17. Study on improving antioxidant and antibacterial activities of silk fibroin by irradiation treatment

    International Nuclear Information System (INIS)

    The silk fibroin solutions were prepared in solvent system of CaCl2. CH3CH2OH. H2O (mole ratio = 1:2:8) followed dialysis against deionized water. The 3% silk fibroin solutions were irradiated under gamma Co-60 source with dose ranging from 0 to 50 kGy at Hanoi Irradiation Centre and bioactivities of the irradiated silk fibroin solutions were investigated with different radiation doses. The results indicated that the antioxidant and antibacterial activities of fibroin were much improved by gamma irradiation. Maximum value of DPPH radical scavenging activity was 70.4% for the solution of silk fibroin irradiated at 10 kGy. Silk fibroin solutions irradiated at doses higher than 10 kGy also exhibited rather high antibacterial activity against E. coli and S. aureus. In order to estimate the applicability of our irradiated fibroin, the silk fibroin solutions were lyophilized to obtain a pure fibroin powder, then their bio-activities were compared with those of commercial silk fibroin (Proteines De Soie/ Zijdeproteine, Bioflore, Canada). Our fibroin powder revealed higher antioxidant and antibacterial activities. The amino acid compositions of our irradiated fibroin were also higher than that of the commercial product. Thus, the irradiated silk fibroin can be used for further application in cosmetic and other related fields. (author)

  18. More than a safety line: jump-stabilizing silk of salticids.

    Science.gov (United States)

    Chen, Yung-Kang; Liao, Chen-Pan; Tsai, Feng-Yueh; Chi, Kai-Jung

    2013-10-01

    Salticids are diurnal hunters known for acute vision, remarkable predatory strategies and jumping ability. Like other jumpers, they strive for stability and smooth landings. Instead of using inertia from swinging appendages or aerodynamic forces by flapping wings as in other organisms, we show that salticids use a different mechanism for in-air stability by using dragline silk, which was previously believed to function solely as a safety line. Analyses from high-speed images of jumps by the salticid Hasarius adansoni demonstrate that despite being subject to rearward pitch at take-off, spiders with dragline silk can change body orientation in the air. Instantaneous drag and silk forces calculated from kinematic data further suggest a comparable contribution to deceleration and energy dissipation, and reveal that adjustments by the spider to the silk force can reverse its body pitch for a predictable and optimal landing. Without silk, upright-landing spiders would slip or even tumble, deferring completion of landing. Thus, for salticids, dragline silk is critical for dynamic stability and prey-capture efficiency. The dynamic functioning of dragline silk revealed in this study can advance the understanding of silk's physiological control over material properties and its significance to spider ecology and evolution, and also provide inspiration for future manoeuvrable robot designs. PMID:23925983

  19. Energy absorption and failure response of silk/epoxy composite square tubes: Experimental

    DEFF Research Database (Denmark)

    Oshkovr, Simin Ataollahi; Taher, Siavash Talebi; A. Eshkoor, Rahim; Ariffin, Ahmad Kamal; Azhari, Che Husna

    2012-01-01

    This paper focuses on natural silk/epoxy composite square tubes energy absorption and failure response. The tested specimens were featured by a material combination of different lengths and same numbers of natural silk/epoxy composite layers in form of reinforced woven fabric in thermosetting epoxy...

  20. Silk sericin loaded alginate nanoparticles: Preparation and anti-inflammatory efficacy.

    Science.gov (United States)

    Khampieng, Thitikan; Aramwit, Pornanong; Supaphol, Pitt

    2015-09-01

    In this study, silk sericin loaded alginate nanoparticles were prepared by the emulsification method followed by internal crosslinking. The effects of various silk sericin loading concentration on particle size, shape, thermal properties, and release characteristics were investigated. The initial silk sericin loadings of 20, 40, and 80% w/w to polymer were incorporated into these alginate nanoparticles. SEM images showed a spherical shape and small particles of about 71.30-89.50 nm. TGA analysis showed that thermal stability slightly increased with increasing silk sericin loadings. FTIR analysis suggested interactions between alginate and silk sericin in the nanoparticles. The release study was performed in acetate buffer at normal skin conditions (pH 5.5; 32 °C). The release profiles of silk sericin exhibited initial rapid release, consequently with sustained release. These silk sericin loaded alginate nanoparticles were further incorporated into topical hydrogel and their anti-inflammatory properties were studied using carrageenan-induced paw edema assay. The current study confirms the hypothesis that the application of silk sericin loaded alginate nanoparticle gel can inhibit inflammation induced by carrageenan. PMID:26188300

  1. Thai Silk Pattern: Conservation and Manufacturing Development to Create Added Value in the Province of Khon Kaen

    Directory of Open Access Journals (Sweden)

    Kesini Sawatdi

    2013-09-01

    Full Text Available Silk patterns are works of art that resembles the valuable and unique ethnic culture that is most important to the community. The history and development of silk patterns in the province of Khon Kaen can be divided into 2 periods, before and after the year 1976. During these periods there were many changes in the manufacturing of silk textiles. The origin of classical silk patterns came from direct modeling of plants, animals and nature. Contemporary silk patterns are modeled after mediums such as television, multimedia, publications and from client requests. The manufacturing tools have also been greatly improved from wooden tools to tools made from metals and tools reinforce with steel. Electric motors have also been utilized in increasing the efficiency in the transformation of silk such as in process of dyeing and spooling silk threads. Traditional materials in silk textile production utilized traditional home grown and produced silk threads while in modern times, the silk comes from factories and purchased in spools. Locally produced silk threads are still produced but in lesser quantity because natural pigments and threads are limited in color. Modern silk threads produced from factories come in many colors and sizes to choose from. Traditional designs and patterns of silk textiles had to be memorized and were passed down orally while contemporary patterns can be massed produced through patterns embedded in graph paper and computer graphic designs. The patterns of silk textiles have greatly improved after 1976 where many efforts were implemented to develop added value and broader market for silk textile products.

  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. Grading Standards of the Coefficient of Variation in the Electronic Raw Silk Size Testing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to shorten the difference between the raw silk size grading standards of the world and that of China,to quicken the step of the electronic raw silk testing process,the distribution of the coefficient of variation (CV50m%) of the raw silk size in the electronic testing and the development of the new standards are studied according to the sampling and grading theory. By the theoretical deduction and the simulating experiments, the distribution of the coefficient of variation of the raw silk size is given,and the grading scheme whose quality index is the coefficient of variation(CV50m%)of the raw silk size and the grading precisions of all grades are proposed. Moreover,the rightness and the feasibility of the grading scheme are testified by the sampling and grading simulation.

  4. E-Commerce in silk industry of Assam: A critical study

    Directory of Open Access Journals (Sweden)

    Mithun Chandra Roy

    2013-04-01

    Full Text Available In today’s over changing market, it is very difficult for the business to survive without proper marketing facility and the influence have clearly shown in the silk industry of Assam which is flourished but the over changing modern technology affect in silk industry of Assam. Now a days most of the business sectors adopting modern technology and flourish on the contrary the silk industry of Assam which is now centered in Sualkuchi known as the Asia’s largest silk village have fallen on bad days and unable to face competition from modern technology with the fast growing modern weaving techniques and more of that unable to compete the powerloom products. The produce of Sualkuchi depending on age-old and traditional method of weaving started to see its downfall. This article comprising about the benefits of E-Commerce in an organisation and an overview of silk industry of Assam.

  5. Persistence and variation in microstructural design during the evolution of spider silk

    Science.gov (United States)

    Madurga, R.; Blackledge, T. A.; Perea, B.; Plaza, G. R.; Riekel, C.; Burghammer, M.; Elices, M.; Guinea, G.; Pérez-Rigueiro, J.

    2015-10-01

    The extraordinary mechanical performance of spider dragline silk is explained by its highly ordered microstructure and results from the sequences of its constituent proteins. This optimized microstructural organization simultaneously achieves high tensile strength and strain at breaking by taking advantage of weak molecular interactions. However, elucidating how the original design evolved over the 400 million year history of spider silk, and identifying the basic relationships between microstructural details and performance have proven difficult tasks. Here we show that the analysis of maximum supercontracted single spider silk fibers using X ray diffraction shows a complex picture of silk evolution where some key microstructural features are conserved phylogenetically while others show substantial variation even among closely related species. This new understanding helps elucidate which microstructural features need to be copied in order to produce the next generation of biomimetic silk fibers.

  6. Properties of radicals created by γ-ray irradiation of silk fabrics

    International Nuclear Information System (INIS)

    The properties of radicals from γ-ray irradiated silk fabrics were studied by electron spin resonance method (ESR). The ESR spectra of silk fabrics irradiated in N2 showed a doublet at room temperature. The doublet became a singlet at g = 2.0057 after placing the sample in air for 24 hours. This can be explained by formation of peroxide radicals. The radical concentration of the irradiated silk fabric and the decay rate of radicals are significantly affected by irradiation conditions, which include the absorbed dose, atmosphere, and water content of the silk fabric samples. However, no dose rate effect on the radical concentration was observed. The results are of help in authors' practice of property modification of silk products by radiation graft copolymerization

  7. Properties of radicals created by γ-ray irradiation of silk fabrics

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The properties of radicals from γ-ray irradiated silk fabrics were studiedby electron spin resonance method (ESR). The ESR spectra of silk fabrics irradiated inN2 showed a doublet at room temperature. The doublet became a singlet at g=2.0057after placing the sample in air for 24 hours. This can be explained by formation ofperoxide radicals. The radical concentration of the irradiated silk fabric and the decayrate of radicals are significantly affected by irradiation conditions, which include theabsorbed dose, atmosphere, and water content of the silk fabric samples. However, nodose rate effect on the radical concentration was observed. The results are of help in ourpractice of property modification of silk products by radiation graft copolymerization.``

  8. Effect of Sericin on Mechanical Behavior of Composite Material Reinforced by Silk Woven Fabric

    Science.gov (United States)

    Kimura, Teruo; Ino, Haruhiro; Hanada, Koji; Katori, Sigetaka

    Recent, attention has been given to shift from glass fibers and carbon fibers to natural fibers for FRP composites for the goal of protecting the environment. This paper concerned with the application of silk fabric for composite materials. Polypropylene (PP) was used for the matrix material and the silk fabric composites were molded using a compression molding method. Especially, the effect of sericin on mechanical behaviors of composite materials was discussed. Good adhesion between silk and PP was obtained by removing the sericin existing around the fibroin. The tensile modulus of composite decreased with decreasing the sericin because of the flexibility of silk fibers without sericin. In particular, the higher Izod impact value was obtained for the composites containing the silk fibers without sericin.

  9. Preparation of conductive silk fabric with antibacterial properties by electroless silver plating

    Science.gov (United States)

    Yu, Dan; Kang, Gengen; Tian, Weicheng; Lin, Lu; Wang, Wei

    2015-12-01

    To obtain an efficient approach to metalize silk fabric, a novel method was explored and silver-plated silk was prepared. In this study, tris (2-carboxyethyl) phosphine (TCEP) was utilized as a reducing agent to generate thiol groups on the silk surface. These thiol groups react with silver ions to form metal complexes, which were used as catalytic seeds and successfully initiated electroless silver plating. A variety of methods, including Raman, XRD, TG, SEM and EDS were used to characterize the intermediates and final products. The results showed that a uniform and smooth metal layer could be obtained when compared with that without TCEP pretreatment. The silver-plated silk fabric exhibited good electrical conductivity and high anti-bacterial properties. These attractive features enable this conductive silk fabric to be a good candidate as a biomedical material.

  10. Role of humidity on the structures and properties of regenerated silk fibers

    Directory of Open Access Journals (Sweden)

    Qingfa Peng

    2015-10-01

    Full Text Available Silk fiber was processed from highly concentrated spinning dope to solid fibers along with water removal. To understand the mechanism of water removal during silk fiber spinning process, a microfluidic chip was designed and applied to investigate the structures and mechanical properties of two kinds of regenerated silk fibroin fibers dry-spun at different relative humidity. The experimental results showed that the diameters of the fibers spun at 40% RH are always larger than the fibers spun at 50% RH due to different removal rates of water. The fibers spun at low humidity contain more β-sheet structure and lower degree of chain orientation and crystalline orientation. These results indicate that the fast phase transition of silk fibroin from sol–gel to silk fiber undergoes with rapid water removal and higher fiber orientation relates to more residue water and drawing force.

  11. Research On Degradation Of Silk Fibroin By Combination Of Electron Beam Irradiation And Hydrothermal Processing

    International Nuclear Information System (INIS)

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The protein content increased from 0.4617 to 0.6530 mg/mg when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  12. Preparation and characterization of silk fibroin as a biomaterial with potential for drug delivery

    Directory of Open Access Journals (Sweden)

    Zhang Hao

    2012-06-01

    Full Text Available Abstract Background Degummed silk fibroin from Bombyx mori (silkworm has potential carrier capabilities for drug delivery in humans; however, the processing methods have yet to be comparatively analyzed to determine the differential effects on the silk protein properties, including crystalline structure and activity. Methods In this study, we treated degummed silk with four kinds of calcium-alcohol solutions, and performed secondary structure measurements and enzyme activity test to distinguish the differences between the regenerated fibroins and degummed silk fibroin. Results Gel electrophoresis analysis revealed that Ca(NO32-methanol, Ca(NO32-ethanol, or CaCl2-methanol treatments produced more lower molecular weights of silk fibroin than CaCl2-ethanol. X-ray diffraction and Fourier-transform infrared spectroscopy showed that CaCl2-ethanol produced a crystalline structure with more silk I (α-form, type II β-turn, while the other treatments produced more silk II (β-form, anti-parallel β-pleated sheet. Solid-State 13C cross polarization and magic angle spinning-nuclear magnetic resonance measurements suggested that regenerated fibroins from CaCl2-ethanol were nearly identical to degummed silk fibroin, while the other treatments produced fibroins with significantly different chemical shifts. Finally, enzyme activity test indicated that silk fibroins from CaCl2-ethanol had higher activity when linked to a known chemotherapeutic drug, L-asparaginase, than the fibroins from other treatments. Conclusions Collectively, these results suggest that the CaCl2-ethanol processing method produces silk fibroin with biomaterial properties that are appropriate for drug delivery.

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

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2016-01-01

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

  14. Influence of Water Content on the β-Sheet Formation, Thermal Stability, Water Removal, and Mechanical Properties of Silk Materials.

    Science.gov (United States)

    Yazawa, Kenjiro; Ishida, Kana; Masunaga, Hiroyasu; Hikima, Takaaki; Numata, Keiji

    2016-03-14

    Silk, which has excellent mechanical toughness and is lightweight, is used as a structural material in nature, for example, in silkworm cocoons and spider draglines. However, the industrial use of silk as a structural material has garnered little attention. For silk to be used as a structural material, its thermal processability and associated properties must be well understood. Although water molecules influence the glass transition of silk, the effects of water content on the other thermal properties of silks are not well understood. In this study, we prepared Bombyx mori cocoon raw fibers, degummed fibers, and films with different water contents and then investigated the effects of water content on crystallization, degradation, and water removal during thermal processing. Thermal gravimetric analyses of the silk materials showed that water content did not affect the thermal degradation temperature but did influence the water removal behavior. By increasing the water content of silk, the water molecules were removed at lower temperatures, indicating that the amount of free water in silk materials increased; additionally, the glass transition temperature decreased with increasing water plasticization. Differential scanning calorimetry and wide-angle X-ray scattering of the silk films also suggested that the water molecules in the amorphous regions of the silk films acted as a plasticizer and induced β-sheet crystallization. The plasticizing effect of water was not detected in silk fibers, owing to their lower amorphous content and mobility. The structural and mechanical characterizations of the silk films demonstrated the silk film prepared at RH 97% realized both crystallinity and ductility simultaneously. Thus, the thermal stability, mechanical, and other properties of silk materials are regulated by their water content and crystallinity. PMID:26835719

  15. A novel Bruch's membrane-mimetic electrospun substrate scaffold for human retinal pigment epithelium cells.

    Science.gov (United States)

    Xiang, Ping; Wu, Kun-Chao; Zhu, Ying; Xiang, Lue; Li, Chong; Chen, Deng-Long; Chen, Feng; Xu, Guotong; Wang, Aijun; Li, Min; Jin, Zi-Bing

    2014-12-01

    Various artificial membranes have been used as scaffolds for retinal pigment epithelium cells (RPE) for monolayer reconstruction, however, long-term cell viability and functionality are still largely unknown. This study aimed to construct an ultrathin porous nanofibrous film to mimic Bruch's membrane, and in particular to investigate human RPE cell responses to the resultant substrates. An ultrathin porous nanofibrous membrane was fabricated by using regenerated wild Antheraea pernyi silk fibroin (RWSF), polycaprolactone (PCL) and gelatin (Gt) and displayed a thickness of 3-5 μm, with a high porosity and an average fiber diameter of 166 ± 85 nm. Human RPE cells seeded on the RWSF/PCL/Gt membranes showed a higher cell growth rate (p < 0.05), and a typical expression pattern of RPE signature genes, with reduced expression of inflammatory mediators. With long-term cultivation on the substrates, RPE cells exhibited characteristic polygonal morphology and development of apical microvilli. Immunocytochemisty demonstrated RPE-specific expression profiles in cells after 12-weeks of co-culture on RWSF/PCL/Gt membranes. Interestingly, the cells on the RWSF/PCL/Gt membranes functionally secreted polarized PEDF and phagocytosed labeled porcine POS. Furthermore, RWSF/PCL/Gt membranes transplanted subsclerally exhibited excellent biocompatibility without any evidence of inflammation or rejection. In conclusion, we established a novel RWSF-based substrate for growth of RPE cells with excellent cytocompatibility in vitro and biocompatibility in vivo for potential use as a prosthetic Bruch's membrane for RPE transplantation. PMID:25220295

  16. NMR analysis of silk for the interpretation of ancient history

    International Nuclear Information System (INIS)

    The aim of this paper is the characterization of archaeological silk with the aid of nuclear magnetic resonance (NMR). In this paper the nucleus is confined to 13C as a stable isotope carbon which is the most basic element in organic compounds. Among the stable carbon isotopes 12C is the most abundant but it has no magnetic moment and the natural abundance of 13C is only 1.108% and this isotope is frequently used in NMR due to its non-zero magnetic moment

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

    Science.gov (United States)

    Shivananda, C. S.; Rao, B. Lakshmeesha; Madhukumar, R.; Sarojini, B. K.; Somashekhar, R.; Asha, S.; Sangappa, Y.

    2016-05-01

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

  18. Heat Capacity of Spider Silk-like Block Copolymers

    OpenAIRE

    Huang, Wenwen; Krishnaji, Sreevidhya; Hu, Xiao; Kaplan, David; Cebe, Peggy

    2011-01-01

    We synthesized and characterized a new family of di-block copolymers based on the amino acid sequences of Nephila clavipes major ampulate dragline spider silk, having the form HABn and HBAn (n=1–3), comprising an alanine-rich hydrophobic block, A, a glycine-rich hydrophilic block, B, and a histidine tag, H. The reversing heat capacities, Cp(T), for temperatures below and above the glass transition, Tg, were measured by temperature modulated differential scanning calorimetry. For the solid sta...

  19. PHYTOCHEMICAL INVESTIGATION OF THE SILK COCOONS OF BOMBYX MORI L.

    Directory of Open Access Journals (Sweden)

    Kaskoos Raad A.

    2012-05-01

    Full Text Available Silk cocoons, produced by Bombyx mori L. (Bombicidae are useful as hypotensive, expectorant, bronchodilator and attenuant drug in traditional medicine. Phytochemical investigation of the ethanolic extract of the cocoons led to the isolation of new phenolic constituents identified as n-butyl-3,4-dihydroxybenzoate (1, 3′,8′,9′-trigeranilanyl-3,4-dihydroxybenzoate (2, 3′,7′-dimethyl-3′-hydroxy-octanyl gallate (3, 3,4-dihydroxyphenyl-n-pentanyl ether (4 and 2,3,4-trihydoxypenyl-n-pentanyl ether (5 on the basis of spectral data analysis.

  20. Electrophoretic deposition of tetracycline modified silk fibroin coatings for functionalization of titanium surfaces

    Science.gov (United States)

    Zhang, Zhen; Qu, Yinying; Li, Xiaoshuang; Zhang, Sheng; Wei, Qingsong; Shi, Yusheng; Chen, Lili

    2014-06-01

    Electrophoretic deposition has been widely used for the fabrication of functional coatings onto metal implant. A characteristic feature of this process is that positively charged materials migrate toward the cathode and can deposit on it. In this study, silk fibroin was decorated with tetracycline in aqueous solution to impart positive charge, and then deposited on negatively titanium cathode under certain electric field. The characterization of the obtained coatings indicated that the intermolecular hydrogen bonds formed between the backbone of silk fibroin and tetracycline molecular. In vitro biological tests demonstrated that osteoblast-like cells achieved acceptable cell affinity on the tetracycline cross-linked silk fibroin coatings, although greater cell viability was seen on pure silk fibroin coatings. The cationic silk fibroin coatings showed remarkable antibacterial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. Therefore, we concluded that electrophoretic deposition was an effective and efficient technique to prepare cationic silk fibroin coatings on the titanium surface and that cationic silk fibroin coatings with acceptable biocompatibility and antibacterial property were promising candidates for further loading of functional agents.

  1. Facile Fabrication of Multifunctional Hybrid Silk Fabrics with Controllable Surface Wettability and Laundering Durability.

    Science.gov (United States)

    Chen, Fengxiang; Yang, Huiyu; Liu, Xin; Chen, Dongzhi; Xiao, Xingfang; Liu, Keshuai; Li, Jing; Cheng, Fan; Dong, Binhai; Zhou, Yingshan; Guo, Zhiguang; Qin, Yong; Wang, Shimin; Xu, Weilin

    2016-03-01

    To obtain a hydrophobic surface, TiO2 coatings are deposited on the surface of silk fabric using atomic layer deposition (ALD) to realize a hierarchical roughness structure. The surface morphology and topography, structure, and wettability properties of bare silk fabric and TiO2-coated silk fabrics thus prepared are evaluated using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FESEM), scanning probe microscope (SPM), X-ray diffraction (XRD), static water contact angles (WCAs), and roll-off angles, respectively. The surfaces of the silk fabrics with the TiO2 coatings exhibit higher surface roughnesses compared with those of the bare silk fabric. Importantly, the hydrophobic and laundering durability properties of the TiO2-coated silk fabrics are largely improved by increasing the thickness of the ALD TiO2 coating. Meanwhile, the ALD process has a litter effect on the service performance of silk fabric. Overall, TiO2 coating using an ALD process is recognized as a promising approach to produce hydrophobic surfaces for elastic materials. PMID:26835541

  2. Research on degradation of silk fibroin by combination of electron beam irradiation and hydrothermal processing

    International Nuclear Information System (INIS)

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin samples were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at an appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The soluble silk protein content increased from 0.462 to 0.653 mg protein/mg silk fibroin when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

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

    International Nuclear Information System (INIS)

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

  4. 常温缫丝品种与蚕茧丝胶蛋白溶解性的关系研究%Study on the Relationship between Common Temperature Silk-reeling Variety and the Solubility of Silk Sericin Protein

    Institute of Scientific and Technical Information of China (English)

    陈复生; 叶崇军; 李冰

    2012-01-01

    [目的]探讨常温缫丝的机理.[方法]通过对常温缫丝品种蚕茧丝胶蛋白的练减率进行测定,分析其溶解性.[结果]可常温缫丝、不可常温缫丝蚕茧的丝胶含量没有显著差异.丝胶蛋白质的常温水溶解性也不会受可否常温缫丝影响,说明可否常温缫丝与丝蛋白质的溶解度关系不大.[结论]丝胶蛋白质含量与常温缫丝没有明显相关.%[Objective] The research aimed to discuss the mechanism of room temperature silk reeling. [Method] The degumming loss rate of silk sericin protein of room temperature silk-reeling variety was determined to study its solubility. [ Result] The content of silk sericin protein between room temperature silk-reeling variety and non-room temperature silk-reeling variety had no significant difference. And the solubility of silk sericin protein was not affected by room temperature silk reeling. [ Conclusion] The content of silk sericin protein had obvious relationship with room temperature silk reeling.

  5. A New 'Silk Road' for a New Era of Plant Science

    Institute of Scientific and Technical Information of China (English)

    Sheng Luan; Xiao-ya Chen; Natasha Raikhel; Winslow Briggs

    2008-01-01

    @@ The Silk Road-the route that extends more than 5000 miles through land and sea-served as a critical pathway for commercial and intellectual exchange between China and the rest of Asia, the Mediterranean, and Africa. Those who trod the old Silk Road included merchants and scholars who brought commercial goods, ideology, knowledge, and technology to countries along the path, contributing to the development of the great civilizations, including China, Egypt, Mesopotamia, Persia, the Indian subcontinent, and Rome. Open exchange and collaboration brought prosperity to all parties involved and,indeed, China's most prosperous Tang dynasty benefited greatly from the exchange through the Silk Road.

  6. Silk-mediated synthesis and modification of photoluminescent ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Han Jie; Su Huilan, E-mail: hlsu@sjtu.edu.cn; Xu Jia; Song Weiqiang; Gu Yu; Chen Ying [Shanghai Jiao Tong University, State Key Lab of Metal Matrix Composites (China); Moon, Won-Jin [Gwangju Center, Korea Basic Science Institute (Korea, Republic of); Zhang Di, E-mail: zhangdi@sjtu.edu.cn [Shanghai Jiao Tong University, State Key Lab of Metal Matrix Composites (China)

    2012-02-15

    In this article, a bio-inspired silk-mediated method was established to produce natural material-modified photoluminescent zinc oxide nanoparticles (nano-ZnO). Silk fibroin fibers were employed as the reactive substrates to synthesize nano-ZnO, and silk fibroins (SF) were taken as the biocompatible stabilizers to modify dispersed nano-ZnO. As-prepared nano-ZnO were mainly hexagonal phase particles with diameter around 13 nm. The resulting nano-ZnO/SF hybrids displayed orange emission and good biocompatibility in aqueous system.

  7. High-Q silk fibroin whispering gallery microresonator on a flexible chip

    CERN Document Server

    Xu, Linhua; Zhao, Guangming; Liu, Zhiwen; Yang, Lan

    2016-01-01

    We have experimentally demonstrated on-chip all silk fibroin whispering gallery mode microresonator by using the molding and solution casting technique. The quality factors of the fabricated silk protein microresonators are up to 0.9*10^5. A high-sensitivity thermal sensor was realized in this silk fibroin microtoroid with the sensitivity of 1.17 nm/K, 8 times higher than previous WGM resonantor based thermal sensors. This opens the way to fabricate the biodegradable and biocompatible protein based microresonators on a flexible chip for biophotonics applications in vivo.

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

    OpenAIRE

    Ming-Hui Yang; Tze-Wen Chung; Yi-Shan Lu; Yi-Ling Chen; Wan-Chi Tsai; Shiang-Bin Jong; Shyng-Shiou Yuan; Pao-Chi Liao; Po-Chiao Lin; Yu-Chang Tyan

    2015-01-01

    Silk fibroin (SF) is a protein with bulky hydrophobic domains and can be easily purified as sericin-free silk-based biomaterial. Silk fibroin modified chitosan nanoparticle (SF-CSNP), a biocompatible material, has been widely used as a potential drug delivery system. Our current investigation studied the bio-effects of the SF-CSNP uptake by liver cells. In this experiment, the characterizations of SF-CSNPs were measured by particle size analysis and protein assay. The average size of the SF-C...

  9. Determination of Antimicrobial Activity of the Dyed Silk Fabrics with Some Natural Dyes

    OpenAIRE

    Alkan, Rezan; TORGAN, Emine; AYDIN, Canan; Karadag, Recep

    2015-01-01

    In this study, silk fabric is dyed with natural indigo. Dyed silk fabric with natural indigo was cut in the 20x20 cm2 size. Excluding a fabric, all fabrics were mordanted in the same percentage with alum metal (KAl(SO4)2.12H2O). Then, silk fabrics for green color dyeing are dyed separately with weld (Reseda luteola), gall oak (Quercus infectoria Olivier) and together weld (Reseda luteola) and gall oak (Quercus infectoria) in different percentage. Antimicrobial functionality of the twenty seve...

  10. In vitro phosphorylation as tool for modification of silk and keratin fibrous materials.

    Science.gov (United States)

    Volkov, Vadim; Cavaco-Paulo, Artur

    2016-05-01

    An overview is given of the recent work on in vitro enzymatic phosphorylation of silk fibroin and human hair keratin. Opposing to many chemical "conventional" approaches, enzymatic phosphorylation is in fact a mild reaction and the treatment falls within "green chemistry" approach. Silk and keratin are not phosphorylated in vivo, but in vitro. This enzyme-driven modification is a major technological breakthrough. Harsh chemical chemicals are avoided, and mild conditions make enzymatic phosphorylation a real "green chemistry" approach. The current communication presents a novel approach stating that enzyme phosphorylation may be used as a tool to modify the surface charge of biocompatible materials such as keratin and silk. PMID:27075736

  11. Silk fibroin diaphragm-based fiber-tip Fabry-Perot pressure sensor.

    Science.gov (United States)

    Cheng, Linghao; Wang, Cengzhong; Huang, Yunyun; Liang, Hao; Guan, Bai-Ou

    2016-08-22

    A miniature fiber-optic Fabry-Perot is built on the tip of a single mode fiber with a thin silk fibroin film as the diaphragm for pressure measurement. The silk fibroin film is regenerated from aqueous silk fibroin solution obtained by an environmentally benign fabrication process, which exhibits excellent optical and physicochemical properties, such as transparency in visible and near infrared region, membrane-forming ability, good adhesion, and high mechanical strength. The resulted Fabry-Perot pressure sensor is therefore highly biocompatible and shows good airtightness with a response of 12.3 nm/kPa in terms of cavity length change. PMID:27557238

  12. Gender inequality and entrepreneurship: the Indian silk industry.

    Science.gov (United States)

    Mayoux, L

    1993-12-01

    The production of raw silk yarns from cocoons (reeling) is a crucial middle stage in the silk industry. The author reviews the experience of attempts to encourage women's entrepreneurship in this industry in Karnataka, South India. Reeling is a potentially lucrative field with possibilities for upward mobility from small-scale to large-scale production if credit is readily available. The industry in India employs large numbers of skilled female workers from all communities and is one of few in which a sectoral gender policy is being implemented. While these factors may be thought to be conducive to the development of women entrepreneurs, none were in the areas studied at the time of research. No women were involved in marketing through the official marketing system and no women's co-operatives were operating. While women were listed among registered reelers, men controlled the businesses. Men simply used women to obtain supplementary bank loans or funds through other avenues otherwise open to only women. Policies for women in reeling have therefore proved to be overwhelmingly unsuccessful. The author considers gender inequality and gender policy at length in this context and concludes that the problem is systemic and structural in nature. Policy implications are considered. PMID:12318601

  13. Spider silk-like proteins derived from transgenic Nicotiana tabacum.

    Science.gov (United States)

    Peng, Congyue Annie; Russo, Julia; Gravgaard, Charlene; McCartney, Heather; Gaines, William; Marcotte, William R

    2016-08-01

    The high tensile strength and biocompatibility of spider dragline silk makes it a desirable material in many engineering and tissue regeneration applications. Here, we present the feasibility to produce recombinant proteins in transgenic tobacco Nicotiana tabacum with sequences representing spider silk protein building blocks . Recombinant mini-spidroins contain native N- and C-terminal domains of major ampullate spidroin 1 (rMaSp1) or rMaSp2 flanking an abbreviated number (8, 16 or 32) of consensus repeat domains. Two different expression plasmid vectors were tested and a downstream chitin binding domain and self-cleavable intein were included to facilitate protein purification. We confirmed gene insertion and RNA transcription by PCR and reverse-transcriptase PCR, respectively. Mini-spidroin production was detected by N-terminus specific antibodies. Purification of mini-spidroins was performed through chitin affinity chromatography and subsequent intein activation with reducing reagent. Mini-spidroins, when dialyzed and freeze-dried, formed viscous gelatin-like fluids. PMID:27026165

  14. Review - Trade and Society along the Ancient Silk Road

    Directory of Open Access Journals (Sweden)

    Bina Sengar

    2013-12-01

    Full Text Available Review of: Jacqueline H Fewkes. 2011. Trade and Contemporary Society Along the Silk Road: An Ethno-History of Ladakh. London: Routledge. xiii+196pp; list of plates, Ladakh in the twenty-first century is well known as a religious and touristic destination as well as an Indian border territory with Kargil and Siachin - significant military posts. In contrast, the commercial role of Ladakh in trade within the Himalayan region and along the Silk Route is less explored In this well-researched book, Fewkes presents various components of Ladakh's ethno-history of trade. She focuses on Ladakh since the eighteenth century and its status as a trade center in pre-independence India and thereafter. Its lost legacy of trade and commerce and associated facets of its culture, history, and future challenges are presented compactly in less than 200 pages. The book features an introduction and seven chapters, and is divided into three parts. Part I: Settings, has two chapters: "Beyond the Roof of the World", and "Recognising the Terrain: An Historical Background". Part II: Historical Trade, consists of "The Family Business: Community, Kinship, and Identity"; "Social Strategies for Profit"; "Living in a Material World: Cosmopolitan Elites"; and "The Demise of Trade: Coping with Borders". Part III: The Modern...

  15. An in vitro study of silk stent morphology

    Energy Technology Data Exchange (ETDEWEB)

    Aurboonyawat, Thaweesak [University of Paris 7 Bichat School of Medicine, Department of Functional and Interventional Neuroradiology, Fondation Rothschild Hospital, Paris (France); Siriraj Hospital, Mahidol University, Division of Neurosurgery, Department of Surgery, Bangkok (Thailand); Blanc, Raphael; Piotin, Michel; Spelle, Laurent; Moret, Jacques [University of Paris 7 Bichat School of Medicine, Department of Functional and Interventional Neuroradiology, Fondation Rothschild Hospital, Paris (France); Schmidt, Paul [University of Paris 7 Bichat School of Medicine, Department of Functional and Interventional Neuroradiology, Fondation Rothschild Hospital, Paris (France); The Duluth Clinic Ltd, Duluth, MN (United States); Nakib, Amir [Universite de Paris 12, Laboratoire Images, Signaux et Systemes Intelligents (LISSI, E. A. 3956), Creteil (France)

    2011-09-15

    Morphology of the Silk stent (Balt, Montmorency, France) after deployment is not fully understood, especially in tortuous vessels. An in vitro study was conducted to study morphology and flow-diverting parameters of this stent. Two sets of different-sized and curved polytetrafluoroethylene tubes were studied. To simulate the aneurysm neck, a small hole was created in a tube. A stent was placed in each of the different tubes. Angiographic computerized tomography and macroscopic photography were then obtained. The images were analyzed to calculate a Percentage of Area Coverage (PAC). Good stent conformability was observed. The PAC was 21% in the straight model with matched stent and vessel diameter. In the straight model with an oversized stent, the PAC was increased. In the curved models, dynamic wire repositioning occurred. The repositioning was affected by the size of the stent and the angle of the vessel curve. Compared to the straight model, this increased the PAC in two instances: on the convexity (oversized stent), and on the concavity (matched stent and vessel diameter). The PAC did not significantly change at the sides of the curve. By design, the wires of the silk stent move relative to each other. In a curved model, the PAC is different at the convexity, concavity, and lateral walls. The stent diameter affects the PAC. These results are clinically relevant because it is desirable to maximize and minimize the PAC across the aneurysm neck and branch vessel orifice, respectively. (orig.)

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

    Science.gov (United States)

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

    2015-11-01

    Pure silk fibroin (SF) hydrogel and polycarbazole/silk fibroin (SF/PCZ) hydrogels were fabricated by solvent casting technique to evaluate electromechanical responses, dielectric properties, and cantilever deflection properties as functions of electric field strength, SF concentration, glutaraldehyde concentration, and PCZ concentration in the blends. Electromechanical properties were characterized in oscillatory shear mode at electric field strengths ranging from 0 to 600V/mm and at a temperature of 27°C. For both the pristine SF and SF/PCZ hydrogels, the storage modulus response (ΔG') and the storage modulus sensitivity (ΔG'/G'0) increased dramatically with increasing electric field strength. The pristine hydrogel possessed the highest storage modulus sensitivity value of 5.87, a relatively high value when compared with other previously studied electroactive polymers. With the addition of conductive PCZ in SF hydrogel, the storage modulus sensitivity and the relative dielectric constant decreased; the conductive polymer thus provided the softening effect under electric field. In the deflection response, the dielectrophoresis force and deflection distance increased monotonically with electric field strength, where the pure SF hydrogel showed the highest deflection distance and dielectrophoresis force. PMID:26249559

  17. Functionalized silk assembled from a recombinant spider silk fusion protein (Z-4RepCT) produced in the methylotrophic yeast Pichia pastoris.

    Science.gov (United States)

    Jansson, Ronnie; Lau, Cheuk H; Ishida, Takuya; Ramström, Margareta; Sandgren, Mats; Hedhammar, My

    2016-05-01

    Functional biological materials are a growing research area with potential applicability in medicine and biotechnology. Using genetic engineering, the possibility to introduce additional functions into spider silk-based materials has been realized. Recently, a recombinant spider silk fusion protein, Z-4RepCT, was produced intracellularly in Escherichia coli and could after purification self-assemble into silk-like fibers with ability to bind antibodies via the IgG-binding Z domain. In this study, the use of the methylotrophic yeast Pichia pastoris for production of Z-4RepCT has been investigated. Temperature, pH and production time were influencing the amount of soluble Z-4RepCT retrieved from the extracellular fraction. Purification of secreted Z-4RepCT resulted in a mixture of full-length and degraded silk proteins that failed to self-assemble into fibers. A position in the C-terminal domain of 4RepCT was identified as being subjected to proteolytic cleavage by proteases in the Pichia culture supernatant. Moreover, the C-terminal domain was subjected to glycosylation during production in P. pastoris. These observed alterations of the CT domain are suggested to contribute to the failure in fiber assembly. As alternative approach, Z-4RepCT retrieved from the intracellular fraction, which was less degraded, was used and shown to retain ability to assemble into silk-like fibers after enzymatic deglycosylation. PMID:26814048

  18. Fabrication and photocatalytic performance of electrospun PVA/silk/TiO2 nanocomposite textile

    Science.gov (United States)

    Wu, Ming-Chung; Chan, Shun-Hsiang; Lin, Ting-Han

    2015-02-01

    Many organic/inorganic nanocomposites have been fabricated into fibrous materials using electrospinning techniques, because electrospinning processes have many attractive advantages and the ability to produce relatively large-scale continuous films. In this study, the polyvinyl alcohol (PVA)/silk/titanium dioxide (TiO2) nanocomposite self-cleaning textiles were successfully produced using electrospinning technique. After optimizing electrospinning conditions, we successfully obtained the PVA/silk/TiO2 nanocomposite fibers with average diameter of ˜220 nm and TiO2 concentration can be as high as 18.0 wt.%. For the case of the PVA/silk/TiO2 nanocomposite textile, the color of brilliant green coated on the textile surface changed from the initial green color to colorless after ultraviolet (UV) irradiation. Because of its worthy photocatalytic performance, the developed PVA/silk/TiO2 nanocomposite materials in this study will be beneficial for the design and fabrication of multifunctional fibers and textiles.

  19. Preparation and characterization of noble metal nanocolloids by silk fibroin in situ reduction

    Institute of Scientific and Technical Information of China (English)

    CHEN; Wenxing(陈文兴); WU; Wen(吴雯); CHEN; Haixiang(陈海相); SHEN; Zhiquan(沈之荃)

    2003-01-01

    Noble metal nanocolloids are prepared from their precursors by in situ reduction of a silk fibroin solution at room temperature without any reducing agent. The mechanism, the effects of pH and the molar ratio of the reactants on the reduction reaction are studied by UV-Vis spectroscopy. The structure of the colloids is characterized by FT-IR, TEM and AFM. According to the TEM images, the gold-silk fibroin colloid is a nanostructured bioconjugate with novel core-shell, while the silver-silk fibroin colloid tends to be congregated as clusters having more than ten nanoparticles of silver-silk fibroin. The gold colloid is highly dispersed and stable while the silver colloid is less dispersed and stable than the gold colloid.

  20. Modulated Degradation of Transient Electronic Devices through Multilayer Silk Fibroin Pockets.

    Science.gov (United States)

    Brenckle, Mark A; Cheng, Huanyu; Hwang, Sukwon; Tao, Hu; Paquette, Mark; Kaplan, David L; Rogers, John A; Huang, Yonggang; Omenetto, Fiorenzo G

    2015-09-16

    The recent introduction of transient, bioresorbable electronics into the field of electronic device design offers promise for the areas of medical implants and environmental monitors, where programmed loss of function and environmental resorption are advantageous characteristics. Materials challenges remain, however, in protecting the labile device components from degradation at faster than desirable rates. Here we introduce an indirect passivation strategy for transient electronic devices that consists of encapsulation in multiple air pockets fabricated from silk fibroin. This approach is investigated through the properties of silk as a diffusional barrier to water penetration, coupled with the degradation of magnesium-based devices in humid air. Finally, silk pockets are demonstrated to be useful for controlled modulation of device lifetime. This approach may provide additional future opportunities for silk utility due to the low immunogenicity of the material and its ability to stabilize labile biotherapeutic dopants. PMID:26305434

  1. Inkjet Printing of Regenerated Silk Fibroin: From Printable Forms to Printable Functions.

    Science.gov (United States)

    Tao, Hu; Marelli, Benedetto; Yang, Miaomiao; An, Bo; Onses, M Serdar; Rogers, John A; Kaplan, David L; Omenetto, Fiorenzo G

    2015-08-01

    A formulation of regenerated silk fibroin solution that can be easily functionalized and inkjet printed on numerous surfaces is developed. As an example, the inks can be printed on laboratory gloves that change color when exposed to bacteria. PMID:26079217

  2. Preparation and characterization of silk/silica hybrid biomaterials by sol-gel crosslinking process

    International Nuclear Information System (INIS)

    The silk/silica hybrid biomaterials are synthesized by sol-gel crosslinking process. The chemical and morphological structures of silk/silica hybrids are investigated with micro-FT-IR spectra, X-ray diffraction, SEM, AFM, and DSC. The results show that the crosslinking reactions among inorganic nano-particles, fibroin and 2,4,6-tri[(2-epihydrin-3-bimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-EBAC) take place during sol-gel process. The silk/silica hybrids form new molecular structures containing not only organic fibroin but also inorganic nano-silica particles. The inorganic particles are bounded to the fibroin through covalent bonds. The silk/silica hybrids can form excellent film with very even nanometer particles. The thermal properties of organic/inorganic hybrid are improved.

  3. Hierarchical charge distribution controls self-assembly process of silk in vitro

    Science.gov (United States)

    Zhang, Yi; Zhang, Cencen; Liu, Lijie; Kaplan, David L.; Zhu, Hesun; Lu, Qiang

    2015-12-01

    Silk materials with different nanostructures have been developed without the understanding of the inherent transformation mechanism. Here we attempt to reveal the conversion road of the various nanostructures and determine the critical regulating factors. The regulating conversion processes influenced by a hierarchical charge distribution were investigated, showing different transformations between molecules, nanoparticles and nanofibers. Various repulsion and compressive forces existed among silk fibroin molecules and aggregates due to the exterior and interior distribution of charge, which further controlled their aggregating and deaggregating behaviors and finally formed nanofibers with different sizes. Synergistic action derived from molecular mobility and concentrations could also tune the assembly process and final nanostructures. It is suggested that the complicated silk fibroin assembly processes comply a same rule based on charge distribution, offering a promising way to develop silk-based materials with designed nanostructures.

  4. Effect of silk sericin on morphology and structure of calcium carbonate crystal

    Science.gov (United States)

    Zhao, Rui-Bo; Han, Hua-Feng; Ding, Shao; Li, Ze-Hao; Kong, Xiang-Dong

    2013-06-01

    In this paper, silk sericin was employed to regulate the mineralization of calcium carbonate (CaCO3). CaCO3 composite particles were prepared by the precipitation reaction of sodium carbonate with calcium chloride solution in the presence of silk sericin. The as-prepared samples were collected at different reaction time to study the crystallization process of CaCO3 by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that silk sericin significantly affected the morphology and crystallographic polymorph of CaCO3. With increasing the reaction time, the crystal phase of CaCO3 transferred from calcite dominated to vaterite dominated mixtures, while the morphology of CaCO3 changed from disk-like calcite crystal to spherical vaterite crystal. These studies showed the potential of silk sericin used as a template molecule to control the growth of inorganic crystal.

  5. Electrospun silk-based nanofibrous scaffolds: fiber diameter and oxygen transfer

    OpenAIRE

    Chomachayi, Masoud Dadras; Solouk, Atefeh; Mirzadeh, Hamid

    2016-01-01

    In this study, silk fibroin was extracted from cocoons of silkworms and fabricated into nonwoven mats by electrospinning method. A new model based on the group method of data handling (GMDH) and artificial neural network (ANN) was developed for estimation of the average diameter of electrospun silk fibroin nanofibers. In this regard, concentration, flow rate, voltage, distance, and speed of collector were used as input parameters and average diameter of the fibers was considered as output par...

  6. Quantification of Changes in Mulberry Silk Fabrics due to Different Laundering: Using WAXS Technique

    Science.gov (United States)

    Parameswara, P.; Nivedita, S.; Somashekar, R.

    2011-07-01

    Loom finished mulberry silk fabrics (Taffeta) were machine laundered and hand laundered several times. X-ray diffractograms of pure and laundered fabrics were used to calculate microstructural parameters like average crystallite size (D) and lattice strain (Vegr) employing Williamson-Hall plot. Microstructural parameters were compared with measured mechanical properties like breaking load, tenacity, and elongation of warp yarns unraveled from fabrics. Surface morphology and texture of silk fabrics changed upon washing is evident from SEM images.

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

    Science.gov (United States)

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

    2016-01-11

    Silk fibroin from the domesticated silkworm Bombyx mori is a naturally occurring biopolymer with charged hydrophilic terminal regions that end-cap a hydrophobic core consisting of repeating sequences of glycine, alanine, and serine residues. Taking inspiration from mussels that produce proteins rich in L-3,4-dihydroxyphenylalanine (DOPA) to adhere to a variety of organic and inorganic surfaces, the silk fibroin was functionalized with catechol groups. Silk fibroin was selected for its high molecular weight, tunable mechanical and degradation properties, aqueous processability, and wide availability. The synthesis of catechol-functionalized silk fibroin polymers containing varying amounts of hydrophilic polyethylene glycol (PEG, 5000 g/mol) side chains was carried out to balance silk hydrophobicity with PEG hydrophilicity. The efficiency of the catechol functionalization reaction did not vary with PEG conjugation over the range studied, although tuning the amount of PEG conjugated was essential for aqueous solubility. Adhesive bonding and cell compatibility of the resulting materials were investigated, where it was found that incorporating as little as 6 wt % PEG prior to catechol functionalization resulted in complete aqueous solubility of the catechol conjugates and increased adhesive strength compared with silk lacking catechol functionalization. Furthermore, PEG-silk fibroin conjugates maintained their ability to form β-sheet secondary structures, which can be exploited to reduce swelling. Human mesenchymal stem cells (hMSCs) proliferated on the silks, regardless of PEG and catechol conjugation. These materials represent a protein-based approach to catechol-based adhesives, which we envision may find applicability as biodegradable adhesives and sealants. PMID:26674175

  8. COMPARATIVE STUDY OF HEALTH STATUS BETWEEN COUNTRIES ALONG THE NEW SILK ROAD

    OpenAIRE

    Ju’e Yan; Yanli Li; JianminGao; Leilei Du; Zhiying Zhou

    2016-01-01

    Using World Statistics Data from the year 2012, health status differences between countries along the “New Silk Road” were compared and analyzed. Life expectancy at birth, life expectancy at age 60, healthy life expectancy, neonatal mortality rate, infant mortality rate, under-five mortality rate, maternal mortality ratio, as well as certain disease incidence rates were used. The study indicated that the 12 countries along the New Silk Road had longer life expectancy at birth. Females had lon...

  9. Nanostructure characterization of beta-sheet crystals in silk under various temperatures

    Directory of Open Access Journals (Sweden)

    Zhang Yan

    2014-01-01

    Full Text Available This paper studies the nanostructure characterizations of β-sheet in silk fiber with different reaction temperatures. A molecular dynamic model is developed and simulated by Gromacs software packages. The results reveal the change rules of the number of hydrogen bonds in β-sheet under different temperatures. The best reaction temperature for the β-sheet crystals is also found. This work provides theoretical basis for the designing of materials based on silk.

  10. Optimising a cell factory system for the bioproduction of silk-elastin-like polymers.

    OpenAIRE

    Collins, Tony; Barroca, Mário Jorge Faria; Branca, Fernando; Silva, João Azevedo; Costa, André da; Machado, Raul; Casal, Margarida

    2013-01-01

    Silk-elastin-like proteins (SELPs) combining the physicochemical and biological properties of silk and elastin have a high potential for use in the pharmaceutical, regenerative medicine and materials fields. Their development for use is however restrained by their production levels. Here we describe the production optimisation for a novel recently described SELP in the pETE. coli BL21(DE3) expression system. Both batch production in shake flasks and fed-batch production in ferm...

  11. An evaluation of photodegradation inhibitors in the conservation of naturally dyed historic silks.

    OpenAIRE

    Koussoulou, T.

    2008-01-01

    Photodegradation of naturally dyed historic silks is a problem that confronts many museums. It continues as long as the objects are displayed, as both ultraviolet and visible light are capable of causing degradation. Degradation may be seen in the fading of the dyes and in the loss of textile strength. Five photodegradation inhibitors were tested on silk dyed with natural red dyes and dye combinations in order to evaluate their ability to increase the light fastness. The selected additives be...

  12. Development of a Process for the Spinning of Synthetic Spider Silk

    OpenAIRE

    Copeland, Cameron G.; Bell, Brianne E.; Christensen, Chad D.; Lewis, Randolph V.

    2015-01-01

    Spider silks have unique mechanical properties but current efforts to duplicate those properties with recombinant proteins have been unsuccessful. This study was designed to develop a single process to spin fibers with excellent and consistent mechanical properties. As-spun fibers produced were brittle, but by stretching the fibers the mechanical properties were greatly improved. A water-dip or water-stretch further increased the strength and elongation of the synthetic spider silk fibers. Gi...

  13. Role of hydroxycinnamic acids in the infection of maize silks by fusarium graminearum schwabe.

    OpenAIRE

    Cao Caamaño, Ana; Reid, Lana M.; Butrón Gómez, Ana María; Malvar Pintos, Rosa Ana; Souto, Xosé C.; Santiago Carabelos, Rogelio

    2011-01-01

    In the current study, the hydroxycinnamic acids in silks of diverse maize inbred lines differing in Fusarium resistance were determined at several times after inoculation with Fusarium graminearum or sterile water as control. The main objective was to determine the possible relationship between the hydroxycinnamic acid changes in silks and ear rot resistance. Several changes in the cell-wall-bound hydroxycinnamic acid concentrations were observed after inoculation with F. graminearum, althoug...

  14. The characteristics of bacterial nanocellulose gel releasing silk sericin for facial treatment

    OpenAIRE

    Aramwit, Pornanong; Bang, Nipaporn

    2014-01-01

    Background Recently, naturally derived facial masks with beneficial biological properties have received increasing interest. In this study, silk sericin-releasing bacterial nanocellulose gel was developed to be applied as a bioactive mask for facial treatment. Results The silk sericin-releasing bacterial nanocellulose gel produced at a pH of 4.5 had an ultrafine and extremely pure fiber network structure. The mechanical properties and moisture absorption ability of the gel were improved, comp...

  15. Stacking faults and microstructural parameters in non-mulberry silk fibres

    Indian Academy of Sciences (India)

    S Divakara; S Madhu; R Somashekar

    2009-11-01

    We have analysed the broadening of X-ray reflections observed in non-mulberry silk fibres in terms of stacking faults and microstructural parameters using a single-order method and have, with these parameters, developed, for the first time, a procedure to compute the whole pattern of these silk fibres. The essential deviations in the values of microstructural parameters obtained from line profile and whole pattern fitting procedures are discussed in this paper.

  16. Novel molecular and mechanical properties of egg case silk from wasp spider, Argiope bruennichi.

    Science.gov (United States)

    Zhao, Ai-Chun; Zhao, Tian-Fu; Nakagaki, Koichi; Zhang, Yuan-Song; Sima, Yang-Hu; Miao, Yun-Gen; Shiomi, Kunihiro; Kajiura, Zenta; Nagata, Yoko; Takadera, Masayuki; Nakagaki, Masao

    2006-03-14

    Araneoid spiders use specialized abdominal glands to produce up to seven different protein-based silks/glues that have various mechanical properties. To date, the fibroin sequences encoding egg case fibers have not been fully determined. To gain further understanding of a recently reported spider silk protein gene family, several novel strategies were utilized in this study to isolate two full-length cDNAs of egg case silk proteins, cylindrical silk protein 1 (CySp1, 9.1 kb) and cylindrical silk protein 2 (CySp2, 9.8 kb), from the wasp spider, Argiope bruennichi. Northern blotting analysis demonstrated that CySp1 and CySp2 are selectively expressed in the cylindrical glands. The amino acid composition of raw egg case silk was closely consistent with the deduced amino acid composition based on the sequences of CySp1 and CySp2, which supports the assertion that CySp1 and CySp2 represent two major components of egg case silk. CySp1 and CySp2 are primarily composed of remarkable homogeneous assemble repeats that are 180 residues in length and consist of several complex subrepeats, and they contain highly homologous C-termini and markedly different N-termini. Our results suggest a possible link between CySp1 and CySp2. In addition, comparisons of stress/strain curves for dragline and egg case silk from Argiope bruennichi showed obvious differences in ultimate strength and extensibility, and similarities in toughness. PMID:16519529

  17. Effect of degumming time on silkworm silk fibre for biodegradable polymer composites

    Science.gov (United States)

    Ho, Mei-po; Wang, Hao; Lau, Kin-tak

    2012-02-01

    Recently, many studies have been conducted on exploitation of natural materials for modern product development and bioengineering applications. Apart from plant-based materials (such as sisal, hemp, jute, bamboo and palm fibre), animal-based fibre is a kind of sustainable natural materials for making novel composites. Silkworm silk fibre extracted from cocoon has been well recognized as a promising material for bio-medical engineering applications because of its superior mechanical and bioresorbable properties. However, when producing silk fibre reinforced biodegradable/bioresorbable polymer composites, hydrophilic sericin has been found to cause poor interfacial bonding with most polymers and thus, it results in affecting the resultant properties of the composites. Besides, sericin layers on fibroin surface may also cause an adverse effect towards biocompatibility and hypersensitivity to silk for implant applications. Therefore, a proper pre-treatment should be done for sericin removal. Degumming is a surface modification process which allows a wide control of the silk fibre's properties, making the silk fibre possible to be used for the development and production of novel bio-composites with unique/specific mechanical and biodegradable properties. In this paper, a cleaner and environmentally friendly surface modification technique for tussah silk in polymer based composites is proposed. The effectiveness of different degumming parameters including degumming time and temperature on tussah silk is discussed through the analyses of their mechanical and morphological properties. Based on results obtained, it was found that the mechanical properties of tussah silk are affected by the degumming time due to the change of the fibre structure and fibroin alignment.

  18. Particulate Sol Route Hydroxyapatite Thin Film-Silk Protein Interface Interactions

    OpenAIRE

    Özcan, Selçuk; ÇİFTÇİOĞLU, Muhsin

    2010-01-01

    Hydroxyapatite (HAp) thin film coatings were prepared on bioinert glass slides by a particulate sol method and the effects of intermediate silk fibroin and silk sericin coatings on the HAp film formation and surface topography were examined. The films prepared with smaller crushed particle sols had a higher agglomeration tendency during the drying consolidation step of the thin film formation, and contained agglomerates larger in number and size, which was demonstrated experimentally and in a...

  19. Physical and chemical aspects of obtaining of sericin from silk waste to size cotton yarn

    OpenAIRE

    Yaminova Zarrina Akramovna

    2015-01-01

    In connection with the transition of the silk industry companies on the market relation, increase in production and processing of products made of natural silk will increase by rational using of raw materials and development of a cocoon-waste processing technologies cocoons. The quality of raw materials and the presence of up to 30% of the natural adhesive as sericin, we carried out research on development of an effective way of obtaining of solution for consideration and dressing powder.

  20. Silk wrapping of nuptial gifts as visual signal for female attraction in a crepuscular spider

    Science.gov (United States)

    Trillo, Mariana C.; Melo-González, Valentina; Albo, Maria J.

    2014-02-01

    An extensive diversity of nuptial gifts is known in invertebrates, but prey wrapped in silk is a unique type of gift present in few insects and spiders. Females from spider species prefer males offering a gift accepting more and longer matings than when males offered no gift. Silk wrapping of the gift is not essential to obtain a mating, but appears to increase the chance of a mating evidencing a particularly intriguing function of this trait. Consequently, as other secondary sexual traits, silk wrapping may be an important trait under sexual selection, if it is used by females as a signal providing information on male quality. We aimed to understand whether the white color of wrapped gifts is used as visual signal during courtship in the spider Paratrechalea ornata. We studied if a patch of white paint on the males' chelicerae is attractive to females by exposing females to males: with their chelicerae painted white; without paint; and with the sternum painted white (paint control). Females contacted males with white chelicerae more often and those males obtained higher mating success than other males. Thereafter, we explored whether silk wrapping is a condition-dependent trait and drives female visual attraction. We exposed good and poor condition males, carrying a prey, to the female silk. Males in poor condition added less silk to the prey than males in good condition, indicating that gift wrapping is an indicator of male quality and may be used by females to acquire information of the potential mate.

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

    Science.gov (United States)

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

    2016-03-01

    Silk fibers are expected to become a pathway to biocompatible and bioresorbable waveguides, which could be used to deliver localized optical power for various applications, e.g., optical therapy or imaging inside living tissue. Here, for the first time, the linear and nonlinear optical properties of natural silk fibers have been studied. The waveguiding properties of silk fibroin of largely unprocessed Bombyx mori silkworm silk are assessed using two complementary methods, and found to be on the average 2.8 dB mm-1. The waveguide losses of degummed silk are to a large extent due to scattering from debris on fiber surface and helical twisting of the fiber. Nonlinear optical microscopy reveals both configurational defects such as torsional twisting, and strong symmetry breaking at the center of the fiber, which provides potential for various nonlinear applications. Our results show that nonregenerated B. mori silk can be used for delivering optical power over short distances, when the waveguide needs to be biocompatible and bioresorbable, such as embedding the waveguide inside living tissue.

  2. Human stem cell neuronal differentiation on silk-carbon nanotube composite

    Science.gov (United States)

    Chen, Chi-Shuo; Soni, Sushant; Le, Catherine; Biasca, Matthew; Farr, Erik; Chen, Eric Y.-T.; Chin, Wei-Chun

    2012-02-01

    Human embryonic stem cells [hESCs] are able to differentiate into specific lineages corresponding to regulated spatial and temporal signals. This unique attribute holds great promise for regenerative medicine and cell-based therapy for many human diseases such as spinal cord injury [SCI] and multiple sclerosis [MS]. Carbon nanotubes [CNTs] have been successfully used to promote neuronal differentiation, and silk has been widely applied in tissue engineering. This study aims to build silk-CNT composite scaffolds for improved neuron differentiation efficiency from hESCs. Two neuronal markers (β-III tubulin and nestin) were utilized to determine the hESC neuronal lineage differentiation. In addition, axonal lengths were measured to evaluate the progress of neuronal development. The results demonstrated that cells on silk-CNT scaffolds have a higher β-III tubulin and nestin expression, suggesting augmented neuronal differentiation. In addition, longer axons with higher density were found to associate with silk-CNT scaffolds. Our silk-CNT-based composite scaffolds can promote neuronal differentiation of hESCs. The silk-CNT composite scaffolds developed here can serve as efficient supporting matrices for stem cell-derived neuronal transplants, offering a promising opportunity for nerve repair treatments for SCI and MS patients.

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

    Science.gov (United States)

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

    2016-04-01

    Strategies for tissue engineering focus on scaffolds with tunable structure and morphology as well as optimum surface chemistry to simulate the anatomy and functionality of the target tissue. Silk fibroin has demonstrated its potential in supporting cartilaginous tissue formation both in vitro and in vivo. In this study, we investigate the role of controlled lamellar organization and chemical composition of biofunctionalized silk scaffolds in replicating the structural properties of the annulus region of an intervertebral disc using articular chondrocytes. Covalent attachment of chondroitin sulfate (CS) to silk is characterized. CS-conjugated silk constructs demonstrate enhanced cellular metabolic activity and chondrogenic redifferentiation potential with significantly improved mechanical properties over silk-only constructs. A matrix-assisted laser desorption ionization-time of flight analysis and protein-protein interaction studies help to generate insights into how CS conjugation can facilitate the production of disc associated matrix proteins, compared to a silk-only based construct. An in-depth understanding of the interplay between such extra cellular matrix associated proteins should help in designing more rational scaffolds for cartilaginous disc regeneration needs. PMID:27068621

  4. Characterization and mechanical performance study of silk/PVA cryogels: towards nucleus pulposus tissue engineering

    International Nuclear Information System (INIS)

    Poly (vinyl) alcohol (PVA) cryogels are reported in the literature for application in nucleus pulposus (NP) replacement strategies. However, these studies are mainly limited to acellular approaches—in part due to the high hydrophilicity of PVA gels that renders cellular adhesion difficult. Silk is a versatile biomaterial with excellent biocompatibility. We hypothesize that the incorporation of silk with PVA will (i) improve the cell-hosting abilities of PVA cryogels and (ii) allow better tailoring of physical properties of the composite cryogels for an NP tissue engineering purpose. 5% (wt/vol) PVA is blended with 5% silk fibroin (wt/vol) to investigate the effect of silk : PVA ratios on the cryogels’ physical properties. Results show that the addition of silk results in composite cryogels that are able to swell to more than 10 times its original dry weight and rehydrate to at least 70% of its original wet weight. Adding at least 20% silk significantly improves surface hydrophobicity and is correlated with an improvement in cell-hosting abilities. Cell-seeded cryogels also display an increment in compressive modulus and hoop stress values. In all, adding silk to PVA creates cryogels that can be potentially used as NP replacements. (paper)

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

    Science.gov (United States)

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

    2016-04-01

    Films prepared from silk fibroin have shown potential as biomaterials in tissue engineering applications for the eye. Here, we present a novel process for fabrication of silk fibroin films for corneal application. In this work, fabrication of silk fibroin films was simply achieved by centrifugal force. In contrast to the conventional dry casting method, we carried out the new process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force was imposed on an aluminum tube containing silk fibroin solution. In the present study, we also compared the surface roughness, mechanical properties, transparency, and cell proliferation between centrifugal and dry casting method. In terms of surface morphology, films fabricated by the centrifugal casting have less surface roughness than those by the dry casting. For elasticity and transparency, silk fibroin films obtained from the centrifugal casting had favorable results compared with those prepared by dry casting. Furthermore, primary human corneal keratocytes grew better in films prepared by the centrifugal casting. Therefore, our results suggest that this new fabrication process for silk fibroin films offers important potential benefits for corneal tissue regeneration. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 508-514, 2016. PMID:25939800

  6. Comparative Transcriptome Analysis Reveals Different Silk Yields of Two Silkworm Strains

    Science.gov (United States)

    Li, Juan; Qin, Sheng; Yu, Huanjun; Zhang, Jing; Liu, Na; Yu, Ye; Hou, Chengxiang; Li, Muwang

    2016-01-01

    Cocoon and silk yields are the most important characteristics of sericulture. However, few studies have examined the genes that modulate these features. Further studies of these genes will be useful for improving the products of sericulture. JingSong (JS) and Lan10 (L10) are two strains having significantly different cocoon and silk yields. In the current study, RNA-Seq and quantitative polymerase chain reaction (qPCR) were performed on both strains in order to determine divergence of the silk gland, which controls silk biosynthesis in silkworms. Compared with L10, JS had 1375 differentially expressed genes (DEGs; 738 up-regulated genes and 673 down-regulated genes). Nine enriched gene ontology (GO) terms were identified by GO enrichment analysis based on these DEGs. KEGG enrichment analysis results showed that the DEGs were enriched in three pathways, which were mainly associated with the processing and biosynthesis of proteins. The representative genes in the enrichment pathways and ten significant DEGs were further verified by qPCR, the results of which were consistent with the RNA-Seq data. Our study has revealed differences in silk glands between the two silkworm strains and provides a perspective for understanding the molecular mechanisms determining silk yield. PMID:27159277

  7. Silk moths in Madagascar: A review of biology, uses and challenges related to Borocera cajani (Vinson, 1863) (Lepidoptera: Lasiocampidae)

    OpenAIRE

    Razafimanantsoa, TM; Rajoelison, G.; Ramamonjisoa, B.; Raminosoa, N.; Poncelet, M; Bogaert, J.; Haubruge, E.; Verheggen, FJ.

    2012-01-01

    Borocera cajani or "Landibe" (vernacular name) is the wild silk moth that is currently used to produce silk textiles in Madagascar. This species is endemic to Madagascar, and is distributed throughout the island, colonizing the Uapaca bojeri or "Tapia" forest of the central highlands. The forest provides food in the form of plants for B. cajani, including U. bojeri leaves. The species secretes silk at the onset of pupation and for making cocoons. Borocera cajani and its natural habitat are th...

  8. Hox transcription factor Antp regulates sericin-1 gene expression in the terminal differentiated silk gland of Bombyx mori

    OpenAIRE

    Kimoto, Mai; Tsubota, Takuya; Uchino, Keiro; Sezutsu, Hideki; Takiya, Shigeharu

    2014-01-01

    Hox genes are well-known master regulators in developmental morphogenesis along the anteroposterior axis of animals. However, the molecular mechanisms by which Hox proteins regulate their target genes and determine cell fates are not fully understood. The silk gland of Bombyx mori is a tubular tissue divided into several subparts along the anteroposterior axis, and the silk genes are expressed with specific patterns. The sericin-1 gene (ser1) is expressed in the middle silk gland (MSG) with s...

  9. Proteome identification of the silkworm middle silk gland.

    Science.gov (United States)

    Li, Jian-Ying; Ye, Lu-Peng; Che, Jia-Qian; Song, Jia; You, Zheng-Ying; Wang, Shao-Hua; Zhong, Bo-Xiong

    2016-03-01

    To investigate the functional differentiation among the anterior (A), middle (M), and posterior (P) regions of silkworm middle silk gland (MSG), their proteomes were characterized by shotgun LC-MS/MS analysis with a LTQ-Orbitrap mass spectrometer. To get better proteome identification and quantification, triplicate replicates of mass spectrometry analysis were performed for each sample. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (Vizcaíno et al., 2014) [1] via the PRIDE partner repository (Vizcaino, 2013) [2] with the dataset identifier PXD003371. The peptide identifications that were further processed by PeptideProphet program in Trans-Proteomic Pipeline (TPP) after database search with Mascot software were also available in .XML format files. Data presented here are related to a research article published in Journal of Proteomics by Li et al. (2015) [3]. PMID:26937469

  10. Dyeing Properties of Natural Dye Syzygium cuminii on Silk

    Science.gov (United States)

    Narayana Swamy, V.; Ninge Gowda, K. N.; Sudhakar, R.

    2014-04-01

    Dyeing behavior of natural dye extracted from the bark of Syzygium cuminii L has been studied on silk fabric. Colour values and colour co-ordinates were examined in terms of K/S and L* a* b* C and h. A range of shades were obtained by using various mordants and mordanting techniques. Dye was tested for some of the eco-parameters using atomic absorption spectrophotometry and GC/MS. The test results were compared with the set standards to determine the eco-friendliness of natural dye. Their concentrations were much below the stipulated limits. Dyed samples were tested for antimicrobial activity against Gram-positive and Gram-negative bacteria and were found to possess antibacterial activity.

  11. Artificial crawler model for texture analysis on silk fibroin scaffolds

    International Nuclear Information System (INIS)

    Texture plays an important role in computer vision tasks. Several methods of texture analysis are available. However, these methods are not capable of extracting rich detail in images. This paper presents a novel approach to image texture classification based on the artificial crawler model. Here, we propose a new rule of movement that moves artificial crawler agents not only toward higher intensities but also toward lower ones. This strategy is able of capturing more detail because the agents explore the peaks as well as the valleys. Thus, compared with the state-of-the-art method, this approach shows an increased discriminatory power. Experiments on the most well known benchmark demonstrate the superior performance of our approach. We also tested our approach on silk fibroin scaffold analysis, and results indicate that our method is consistent and can be applied in real-world situations. (paper)

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Hao Dou

    2014-01-01

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

  14. Effect of solvents on properties of Bombyx mori silk grafted by methyl methacrylate (MMA and methacrylamide (MAA

    Directory of Open Access Journals (Sweden)

    Wattana Klairatsamee

    2005-11-01

    Full Text Available Mulberry silks were chemically modified in order to increase weight gain, resulting from degumming process using graft copolymerisation technique with vinyl monomers, i.e. MMA, MAA and MMA/MAA. Due to the appearance of PMMA homopolymer granules adhered on the MMA- and MMA/MAA-grafted silk surfaces resulting in surface roughness when silk was grafted by MMA in water, the influence of grafting solvents was examined, using different water/ethanol volume ratios of 100/0, 75/25, 50/50, 25/75 and 0/100. FTIR spectra of the grafted silks presented the absorption bands of the vinyl monomers used for the grafting process. In addition, high values of % polymer add-on were obtained for all of the grafted silks. It was also found that the suitable solvents were 25/75 water/ethanol for the silk grafted by MMA and MMA/MAA, and water for the silk grafted by MAA, in order to get the smooth grafted silk surface and high polymer add-on. Moreover, all the grafted silks showed slightly greater stiffness, as indicated by the increase of Young's modulus and the decrease of elongation.

  15. Bioactive macro/micro porous silk fibroin/Nano-sized calcium phosphate scaffolds with potential for bone tissue engineering applications

    OpenAIRE

    Yan, Leping; Correia, Joana Silva; Correia, C; Caridade, S. G.; Fernandes, E. M.; Sousa, R.A.; Mano, J.F.; Oliveira, Joaquim M.; de Oliveira, A. L.; Reis, R.L.

    2013-01-01

    Aim: The development of novel silk/nano-sized calcium phosphate (silk/nano-CaP) scaffolds with highly dispersed CaP nanoparticles in the silk fibroin (SF) matrix for bone tissue engineering. Materials & methods: Nano-CaP was incorporated in a concentrated aqueous SF solution (16 wt.%) by using an in situ synthesis method. The silk/nano-CaP scaffolds were then prepared through a combination of salt-leaching/ lyophilization approaches. Results: The CaP particles presented good affin...

  16. 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.

  17. 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.

  18. Silk fibroin gelation via non-solvent induced phase separation.

    Science.gov (United States)

    Kasoju, Naresh; Hawkins, Nicholas; Pop-Georgievski, Ognen; Kubies, Dana; Vollrath, Fritz

    2016-03-01

    Tissue engineering benefits from novel materials with precisely tunable physical, chemical and mechanical properties over a broad range. Here we report a practical approach to prepare Bombyx mori silk fibroin hydrogels using the principle of non-solvent induced phase separation (NIPS). A combination of reconstituted silk fibroin (RSF) and methanol (non-solvent), with a final concentration of 2.5% w/v and 12.5% v/v respectively, maintained at 22 °C temperature turned into a hydrogel within 10 hours. Freeze-drying of this gel gave a foam with a porosity of 88%, a water uptake capacity of 89% and a swelling index of 8.6. The gelation kinetics and the loss tangent of the gels were investigated by rheometry. The changes in the morphology of the porous foams were visualized by SEM. The changes in RSF chemical composition and the relative fraction of its secondary structural elements were analyzed by ATR-FTIR along with Fourier self-deconvolution. And, the changes in the glass transition temperature, specific heat capacity and the relative fraction of crystallinity of RSF were determined by TM-DSC. Data suggested that RSF-water-methanol behaved as a polymer-solvent-non-solvent ternary phase system, wherein the demixing of the water-methanol phases altered the thermodynamic equilibrium of RSF-water phases and resulted in the desolvation and eventual separation of the RSF phase. Systematic analysis revealed that both gelation time and the properties of hydrogels and porous foams could be controlled by the ratios of RSF and non-solvent concentration as well as by the type of non-solvent and incubation temperature. Due to the unique properties we envisage that the herein prepared NIPS induced RSF hydrogels and porous foams can possibly be used for the encapsulation of cells and/or for the controlled release of both hydrophilic and hydrophobic drugs. PMID:26730413

  19. Recombinant minimalist spider wrapping silk proteins capable of native-like fiber formation.

    Directory of Open Access Journals (Sweden)

    Lingling Xu

    Full Text Available Spider silks are desirable biomaterials characterized by high tensile strength, elasticity, and biocompatibility. Spiders produce different types of silks for different uses, although dragline silks have been the predominant focus of previous studies. Spider wrapping silk, made of the aciniform protein (AcSp1, has high toughness because of its combination of high elasticity and tensile strength. AcSp1 in Argiope trifasciata contains a 200-aa sequence motif that is repeated at least 14 times. Here, we produced in E. coli recombinant proteins consisting of only one to four of the 200-aa AcSp1 repeats, designated W(1 to W(4. We observed that purified W(2, W(3 and W(4 proteins could be induced to form silk-like fibers by shear forces in a physiological buffer. The fibers formed by W(4 were ∼3.4 µm in diameter and up to 10 cm long. They showed an average tensile strength of 115 MPa, elasticity of 37%, and toughness of 34 J cm(-3. The smaller W(2 protein formed fewer fibers and required a higher protein concentration to form fibers, whereas the smallest W(1 protein did not form silk-like fibers, indicating that a minimum of two of the 200-aa repeats was required for fiber formation. Microscopic examinations revealed structural features indicating an assembly of the proteins into spherical structures, fibrils, and silk-like fibers. CD and Raman spectral analysis of protein secondary structures suggested a transition from predominantly α-helical in solution to increasingly β-sheet in fibers.

  20. Control of silicification by genetically engineered fusion proteins: silk-silica binding peptides.

    Science.gov (United States)

    Zhou, Shun; Huang, Wenwen; Belton, David J; Simmons, Leo O; Perry, Carole C; Wang, Xiaoqin; Kaplan, David L

    2015-03-01

    In the present study, an artificial spider silk gene, 6mer, derived from the consensus sequence of Nephila clavipes dragline silk gene, was fused with different silica-binding peptides (SiBPs), A1, A3 and R5, to study the impact of the fusion protein sequence chemistry on silica formation and the ability to generate a silk-silica composite in two different bioinspired silicification systems: solution-solution and solution-solid. Condensed silica nanoscale particles (600-800 nm) were formed in the presence of the recombinant silk and chimeras, which were smaller than those formed by 15mer-SiBP chimeras, revealing that the molecular weight of the silk domain correlated to the sizes of the condensed silica particles in the solution system. In addition, the chimeras (6mer-A1/A3/R5) produced smaller condensed silica particles than the control (6mer), revealing that the silica particle size formed in the solution system is controlled by the size of protein assemblies in solution. In the solution-solid interface system, silicification reactions were performed on the surface of films fabricated from the recombinant silk proteins and chimeras and then treated to induce β-sheet formation. A higher density of condensed silica formed on the films containing the lowest β-sheet content while the films with the highest β-sheet content precipitated the lowest density of silica, revealing an inverse correlation between the β-sheet secondary structure and the silica content formed on the films. Intriguingly, the 6mer-A3 showed the highest rate of silica condensation but the lowest density of silica deposition on the films, compared with 6mer-A1 and -R5, revealing antagonistic crosstalk between the silk and the SiBP domains in terms of protein assembly. These findings offer a path forward in the tailoring of biopolymer-silica composites for biomaterial related needs. PMID:25462851

  1. 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.

  2. Fixation of silver ions onto silk sericin for silk weighting%银离子固着丝胶增重蚕丝工艺

    Institute of Scientific and Technical Information of China (English)

    杭伟明

    2012-01-01

    In order to keep the silk weight and increase antibacterial capacity of silk fibers, the silk fabric was treated with silver nitrate solution, and the silver ions were fixed onto the silk fibers by coordinate bonds, while the sericin dissolution decreased simultaneously. This paper discussed the usage of silver nitrate, nitric acid and acetic acid, ammonia nitrate and the influence of fixation bath ratio, fixation time, preimpregnation time, etc. on sericin dissolution. As shown by the experimental results, the fixation of silver ions onto silk fiber surface can decrease the silk dissolution and increase the silk fiber weight indirectly. In terms of fixation solution, nitric acid is better than acetic acid, and addition of ammonia nitrate can enhance the fixation rate and decrease the sericin dissolution significantly. Furthermore, the preimpregnation and fixing time should not be too long, and for fixation, short liquor ratio is appropriate.%采用硝酸银处理蚕丝,使银离子通过与蚕丝分子的配位结合附着于纤维上,减少丝胶溶失,达到保持蚕丝重量和起到抗菌功效的目的.分析了硝酸银、硝酸、醋酸、硝酸铵的使用,以及固着液浴比、处理时间、预浸时间等因素对蚕丝丝胶溶失的影响.结果表明:银离子附着于蚕丝纤维后,能减少丝胶的溶失,对蚕丝起间接增重作用,在银离子固着液中,使用硝酸的效果比醋酸好,加入硝酸铵能明显提高丝胶固着,大大减少丝胶溶失;对蚕丝的预浸时间和固着时间不宜过长,固着液浴比以小浴比为宜.

  3. Controllable in situ synthesis of silver nanoparticles on multilayered film-coated silk fibers for antibacterial application.

    Science.gov (United States)

    Meng, Mei; He, Huawei; Xiao, Jing; Zhao, Ping; Xie, Jiale; Lu, Zhisong

    2016-01-01

    Layer-by-layer (LbL) assembly is a versatile technique for the preparation of multilayered polymeric films. However, fabrication of LbL polymetic film on silk for the in situ growth of high-density silver nanoparticles (AgNPs) has not been realized. Herein poly(acrylic acid) (PAA)/poly(dimethyldiallylammonium chloride) (PDDA) multilayers are constructed on silk via the LbL approach, subsequently serving as a 3-dimensional matrix for in situ synthesis of AgNPs. After 8 rounds of LbL assembly, the silk is fully covered with a layer of polymeric film. AgNPs with good crystalline structures could be in-situ generated in the silk-coated multilayers and their amount could be tailored by adjusting the bilayer numbers. The as-prepared silk could effectively kill the existing bacteria and inhibit the bacterial growth, demonstrating the antimicrobial activity. Moreover, the release of Ag(+) from the modified silk can last for 120 h, rendering the modified silk sustainable antimicrobial activity. This work may provide a novel method to prepare AgNPs-functionalized antimicrobial silk for potential applications in textile industry. PMID:26414419

  4. Frame-web-choice experiments with stingless bees support the prey-attraction hypothesis for silk decorations in Argiope savignyi

    NARCIS (Netherlands)

    Galvez, Dumas

    2009-01-01

    There is controversy about the function of silk stabilimenta, also called silk decorations, oil spiders' webs. Most of the proposed hypotheses have been tested using indirect methods. Protection against predators, advertisement for vertebrates to avoid web damage, and increasing prey attraction are

  5. The effect of ageing on the mechanical properties of the silk of the bridge spider Larinioides cornutus (Clerck, 1757)

    Science.gov (United States)

    Lepore, Emiliano; Isaia, Marco; Mammola, Stefano; Pugno, Nicola

    2016-05-01

    Spider silk is regarded as one of the best natural polymer fibers especially in terms of low density, high tensile strength and high elongation until breaking. Since only a few bio-engineering studies have been focused on spider silk ageing, we conducted nano-tensile tests on the vertical naturally spun silk fibers of the bridge spider Larinioides cornutus (Clerck, 1757) (Arachnida, Araneae) to evaluate changes in the mechanical properties of the silk (ultimate stress and strain, Young’s modulus, toughness) over time. We studied the natural process of silk ageing at different time intervals from spinning (20 seconds up to one month), comparing silk fibers spun from adult spiders collected in the field. Data were analyzed using Linear Mixed Models. We detected a positive trend versus time for the Young’s modulus, indicating that aged silks are stiffer and possibly less effective in catching prey. Moreover, we observed a negative trend for the ultimate strain versus time, attesting a general decrement of the resistance force. These trends are interpreted as being due to the drying of the silk protein chains and the reorientation among the fibers.

  6. THE PROJECT OF ECONOMIC BELT OF THE NEW SILK ROAD IN THE RUSSIAN-CHINESE RELATIONS FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Zheng Jielan

    2016-03-01

    Full Text Available The article is about the Chinese initiative to establish the Economic Silk Road. For the first time on such a wish of the Chinese side declared its leader Xi Jinping in 2013 during a visit to Kazakhstan. Particular attention is paid to the role of Russia in the implementation of the Economic Silk Road and nature of potential cooperation of the Eurasian Economic Union and the Economic Silk Road. Economic times are generally Silk Road opens new Russian considerable opportunities. True only if Russia is reasonable, on favorable terms, will take part in this project, based on a serious increasing economic opportunities in China. On the other hand China clearly understands that without cooperation with Russia, without her the Chinese Silk Road project will be incomplete, if not realizable. Northern corridor of the new Silk Road extends from Western China through Kazakhstan to Russia, Orenburg, and then, according to today's China - to St. Petersburg and the Baltic Sea, as well as through Belarus via Warsaw and further - into Western Europe. It is so to say "traditional line" of the Great Silk Road. That is in line with today's Chinese version of the Silk Road Russia is not only a transit country (the country, providing the transit of goods through its territory and gets through this earnings, but also a key partner of the Eurasian corridor in the northern part.

  7. Along the Silk Road: People, Interaction, and Cultural Exchange. A Social Studies Unit Recommended for Grades 6-10.

    Science.gov (United States)

    Stanford Univ., CA. Stanford Program on International and Cross Cultural Education.

    This curriculum unit introduces students to the travelers and traders from the early part of the Han-Roman times up to the 14th century who took great risks in pursuit of silk. A variety of activities explore the development of the Silk Road trade routes, including journal writing, small group reading and writing activities, role play and…

  8. Tarantulas do not shoot silk from their legs: experimental evidence in four species of New World tarantulas.

    Science.gov (United States)

    Pérez-Miles, Fernando; Ortíz-Villatoro, David

    2012-05-15

    Theraphosid tarantulas, like all other spiders, secrete silk from spigots on the abdominal spinnerets. A few years ago, it was proposed that the large tarantula Aphonopelma seemanni could extrude silk from specialized spigots on the tarsi to help adhesion to vertical surfaces. This suggestion was later questioned because silk was not observed after the spinnerets had been sealed. Recently, experiments with the tarantula Grammostola rosea again suggested tarsal silk secretion. All observations of the supposed tarsal silk were made in spiders with functional spinnerets, thus contamination with silk coming from the spinnerets could not be excluded. Recent morphological arguments also questioned putative tarsal spigots and proposed that they are actually contact chemoreceptors. We here test the supposed tarsal silk secretion in Aphonopelma seemanni, Avicularia avicularia, Brachypelma vagans and Grammostola mollicoma using similar experimental conditions as the previous authors, but with sealed spinnerets. Our results clearly demonstrate that when spinnerets are sealed, tarantulas do not show any tarsal silk secretion. We reinterpret those putative tarsal spigots and discuss possible evolutionary implications of these findings. PMID:22539742

  9. A Hox Gene, Antennapedia, Regulates Expression of Multiple Major Silk Protein Genes in the Silkworm Bombyx mori.

    Science.gov (United States)

    Tsubota, Takuya; Tomita, Shuichiro; Uchino, Keiro; Kimoto, Mai; Takiya, Shigeharu; Kajiwara, Hideyuki; Yamazaki, Toshimasa; Sezutsu, Hideki

    2016-03-25

    Hoxgenes play a pivotal role in the determination of anteroposterior axis specificity during bilaterian animal development. They do so by acting as a master control and regulating the expression of genes important for development. Recently, however, we showed that Hoxgenes can also function in terminally differentiated tissue of the lepidopteranBombyx mori In this species,Antennapedia(Antp) regulates expression of sericin-1, a major silk protein gene, in the silk gland. Here, we investigated whether Antpcan regulate expression of multiple genes in this tissue. By means of proteomic, RT-PCR, and in situ hybridization analyses, we demonstrate that misexpression of Antpin the posterior silk gland induced ectopic expression of major silk protein genes such assericin-3,fhxh4, and fhxh5 These genes are normally expressed specifically in the middle silk gland as is Antp Therefore, the evidence strongly suggests that Antpactivates these silk protein genes in the middle silk gland. The putativesericin-1 activator complex (middle silk gland-intermolt-specific complex) can bind to the upstream regions of these genes, suggesting that Antpdirectly activates their expression. We also found that the pattern of gene expression was well conserved between B. moriand the wild species Bombyx mandarina, indicating that the gene regulation mechanism identified here is an evolutionarily conserved mechanism and not an artifact of the domestication of B. mori We suggest that Hoxgenes have a role as a master control in terminally differentiated tissues, possibly acting as a primary regulator for a range of physiological processes. PMID:26814126

  10. Material properties of evolutionary diverse spider silks described by variation in a single structural parameter

    Science.gov (United States)

    Madurga, Rodrigo; Plaza, Gustavo R.; Blackledge, Todd A.; Guinea, Gustavo. V.; Elices, Manuel; Pérez-Rigueiro, José

    2016-01-01

    Spider major ampullate gland silks (MAS) vary greatly in material properties among species but, this variation is shown here to be confined to evolutionary shifts along a single universal performance trajectory. This reveals an underlying design principle that is maintained across large changes in both spider ecology and silk chemistry. Persistence of this design principle becomes apparent after the material properties are defined relative to the true alignment parameter, which describes the orientation and stretching of the protein chains in the silk fiber. Our results show that the mechanical behavior of all Entelegynae major ampullate silk fibers, under any conditions, are described by this single parameter that connects the sequential action of three deformation micromechanisms during stretching: stressing of protein-protein hydrogen bonds, rotation of the β-nanocrystals and growth of the ordered fraction. Conservation of these traits for over 230 million years is an indication of the optimal design of the material and gives valuable clues for the production of biomimetic counterparts based on major ampullate spider silk.

  11. Study On Degradation Of Silk Fibroin By Irradiation Treatment For Cosmetic And Pharmaceutical Applications

    International Nuclear Information System (INIS)

    As a kind of protein, silk fibroin is created with silkworm Bombyx mori in products of silk. The fibroin was irradiated using Co-60 gamma source and its degradability and solubility were investigated with various radiation doses to apply in pharmacy and cosmetic. Addition to the morphological changes of irradiated fibroin fibers shows that its mechanical properties were much influenced by the irradiation. Tensile strength and elongation at break of the silk fibroin significantly decreased with increasing of radiation dose up to 1000 kGy. The tensile strength and elongation at break of the irradiated fibroin at 1000 kGy reduced to 71% and 94% respectively in compared with non-irradiated one. The solubility of silk fibroin in both calcium chloride (CaCl2/C2H5OH/H2O=1:2:8) in mole ratio and distilled water were improved by the irradiation. UV spectrometry revealed the structure of silk fibroin was also changed by irradiation. (author)

  12. Self-assembly of nucleic acids, silk and hybrid materials thereof

    Science.gov (United States)

    Humenik, Martin; Scheibel, Thomas

    2014-12-01

    Top-down approaches based on etching techniques have almost reached their limits in terms of dimension. Therefore, novel assembly strategies and types of nanomaterials are required to allow technological advances. Self-assembly processes independent of external energy sources and unlimited in dimensional scaling have become a very promising approach. Here, we highlight recent developments in self-assembled DNA-polymer, silk-polymer and silk-DNA hybrids as promising materials with biotic and abiotic moieties for constructing complex hierarchical materials in ‘bottom-up’ approaches. DNA block copolymers assemble into nanostructures typically exposing a DNA corona which allows functionalization, labeling and higher levels of organization due to its specific addressable recognition properties. In contrast, self-assembly of natural silk proteins as well as their recombinant variants yields mechanically stable β-sheet rich nanostructures. The combination of silk with abiotic polymers gains hybrid materials with new functionalities. Together, the precision of DNA hybridization and robustness of silk fibrillar structures combine in novel conjugates enable processing of higher-order structures with nanoscale architecture and programmable functions.

  13. Silk formation mechanisms in the larval salivary glands of Apis mellifera (Hymenoptera: Apidae)

    Indian Academy of Sciences (India)

    Elaine C M Silva-Zacarin; Regina L M Silva De Moraes; S R Taboga

    2003-12-01

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th instar and finishes at the end of the same instar. This process begins in the distal secretory portion of the gland, going towards the proximal secretory portion; and from the periphery to the center of the gland lumen. The silk proteins are released from the secretory cells as a homogeneous substance that polymerizes in the lumen to form compact birefringent tactoids. Secondly, the water absorption from the lumen secretion, carried out by secretory and duct cells, promotes aggregation of the tactoids that form a spiral-shape filament with a zigzag pattern. This pattern is also the results of the silk compression in the gland lumen and represents a high concentration of macromolecularly well-oriented silk proteins.

  14. 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. PMID:24615460

  15. Characterization of Natural Dyes and Traditional Korean Silk Fabric by Surface Analytical Techniques

    Directory of Open Access Journals (Sweden)

    Yeonhee Lee

    2013-05-01

    Full Text Available Time-of-flight secondary ion mass spectrometry (TOF-SIMS and X-ray photoelectron spectroscopy (XPS are well established surface techniques that provide both elemental and organic information from several monolayers of a sample surface, while also allowing depth profiling or image mapping to be carried out. The static TOF-SIMS with improved performances has expanded the application of TOF-SIMS to the study of a variety of organic, polymeric and biological materials. In this work, TOF-SIMS, XPS and Fourier Transform Infrared (FTIR measurements were used to characterize commercial natural dyes and traditional silk fabric dyed with plant extracts dyes avoiding the time-consuming and destructive extraction procedures necessary for the spectrophotometric and chromatographic methods previously used. Silk textiles dyed with plant extracts were then analyzed for chemical and functional group identification of their dye components and mordants. TOF-SIMS spectra for the dyed silk fabric showed element ions from metallic mordants, specific fragment ions and molecular ions from plant-extracted dyes. The results of TOF-SIMS, XPS and FTIR are very useful as a reference database for comparison with data about traditional Korean silk fabric and to provide an understanding of traditional dyeing materials. Therefore, this study shows that surface techniques are useful for micro-destructive analysis of plant-extracted dyes and Korean dyed silk fabric.

  16. Processing and characterization of silk sericin from Bombyx mori and its application in biomaterials and biomedicines.

    Science.gov (United States)

    Cao, Ting-Ting; Zhang, Yu-Qing

    2016-04-01

    Bombyx mori silk is composed of 60-80% fibroin, 15-35% sericin and 1-5% non-sericin component including wax, pigments, sugars and other impurities. For two decades, the protein-based silk fibroin was extensively used in the research and development of medical biomaterials and biomedicines. Sericin is frequently ignored and abandoned as a byproduct or waste in the processing of traditional silk fabrics, silk floss or modern silk biomaterials. However, similar to fibroin, sericin is not only a highly useful biological material, but also a lot of biological activity. Moreover, the non-sericin component present with sericin in the cocoon shell also has a strong biological activity. In this review, the extraction and recovery methods of sericin and the non-sericin component from the cocoon layer are reported, and their composition, properties and biological activity are described to produce a comprehensive report on biomedical materials and biological drugs. In addition, related problems or concerns present in the research and development of sericin are discussed, and a potential application of sericin in sustainable development is also presented. PMID:26838924

  17. Cloning and expression of Bombyx mori silk gland elongation factor 1gamma in Escherichia coli.

    Science.gov (United States)

    Kamiie, Katsuyoshi; Nomura, Yoshitaka; Kobayashi, Satoru; Taira, Hideharu; Kobayashi, Kohmei; Yamashita, Tetsuro; Kidou, Shin-ichiro; Ejiri, Shin-ichiro

    2002-03-01

    Elongation factor 1 (EF-1) from the silk gland of Bombyx mori consists of alpha-, beta-, gamma-, and delta-subunits. EF-1alpha GTP catalyzes the binding of aminoacyl-tRNA to ribosomes concomitant with the hydrolysis of GTP. EF-1betagammadelta catalyzes the exchange of EF-1alpha-bound GDP for exogenous GTP and stimulates the EF-1alpha-dependent binding of aminoacyl-tRNA to ribosomes. EF-1gamma cDNA, which contains an open reading frame (ORF) encoding a polypeptide of 423 amino acid residues, was amplified and cloned by PCR from a silk gland cDNA library. The calculated molecular mass and predicted pI of the product were 48,388 Da and 5.84, respectively. The silk gland EF-1gamma shares 67.3% amino acid identity with Artemia salina EF-lgamma. The N-terminal domain (amino acid residues 1-211) of silk gland EF-lgamma is 29.3% identical to maize glutathione S-transferase. We demonstrated that silk gland EF-lgamma bound to glutathione Sepharose, suggesting that the N-terminal domain of EF-1gamma may have the capacity to bind to glutathione. PMID:12005049

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

    International Nuclear Information System (INIS)

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

  19. Study On Improving Antioxydant And Antibacterial Activities Of Silk Fibroin By Irradiation Treatment

    International Nuclear Information System (INIS)

    Silk fibroin at dry state and the solution of 3% were irradiated by Co-60 source at dose ranges 0 - 1000 kGy and 0 - 50 kGy respectively. The results showed that irradiation treatment for fibroin solution have higher effectiveness for improvement of some bio-activities of silk fibroin compared with dry state irradiation treatment due to remarkably reducing of irradiation doses. The antioxidant activity of fibroin was significantly increase by irradiation. The maximum value of DPPH radical scavenging activity was 70.4% when fibroin solution was irradiated at dose of 10 kGy. Irradiated fibroin solution also shown antibacterial activity against tested bacteria strains (E. coli, and S. aureus). In order to estimate the applicability of our irradiated fibroin, the silk fibroin solutions were lyophilized to obtain a pure fibroin powder, then their bio-activities were compared with those of commercial silk fibroin (Proteines De Soie/ Zijdeproteine, Bioflore, Canada). Our fibroin powder revealed higher antioxidant and antibacterial activities. The amino acid compositions of our irradiated fibroin were also higher than that of the commercial product. Thus, the irradiated silk fibroin can be used for further application in cosmetic and other related fields. (author)

  20. Radiation preservation study on middle host eggs of trichogramma species

    International Nuclear Information System (INIS)

    Technical feasibility about the preservation of Antheraea pernyi's eggs, which are used as middle hosts of Trichogramma dendrolimi Matsumura, irradiated by electron beam is studied. The effects of radiation dose, storage temperature on preservative time of eggs are discussed. The results reveal that the preservative time of Antheraea pernyi's eggs irradiated by electron beam, combining with storage in a refrigerator, is notable prolonged in contrast with the control. When the irradiated eggs stored in a refrigerator for 89 days are serviced as hosts, the parasitic percentage for Trichogramma dendrolimi Matsumura is about 80%. Besides, the emergence percentage, average numbers of parasitoids reproduced out of one egg, as well as body size, growing stage periods, and the sexual rate of descendant are all normal. Irradiated eggs have not any adverse effects on the abilities of Trichogramma species and their offspring in both bearing and controlling insect pests

  1. Radiation preservation study on middle host eggs of trichogramma species

    Science.gov (United States)

    Lianzhong, Ding; Zhengdong, Wu; Ping, Jiang; Zulin, Chen; Jianxin, Fu; Jianging, Shi

    1993-10-01

    Technical feasibility on the preservation of Antheraea pernyi's eggs, which are used as the middle hosts of Trichogramma dendrolimi Matsumura, irradiated by electron beam is studied in this paper. The results reveal that the preservative time of Antheraea pernyi's eggs irradiated by electron beam, combining with storage in a refrigerator, is notably prolonged in contrast with the control. When the irradiated eggs stored in a refrigerator for 89 days are serviced as hosts, the parasitic percentage for Trichogramma dendrolimi Matsumura is about 80 %. Besides, the emergence percentage, average numbers of parasitoids reproduced out of one egg, as well as body size, growing stage periods, and sexual rate of descendant are all normal. Irradiated eggs have not any adverse effects on the abilities of Trichogramma species and their offspring in both bearing and controlling insect pests.

  2. Radiation preservation study on middle host eggs of Trichogramma species

    Energy Technology Data Exchange (ETDEWEB)

    Ding Lianzhong; Chen Zulin; Fu Jianxin; Shi Jianqing (Institute of Applied Technical Physics, Hangzhou, ZJ (China)); Wu Zhengdong (Chang Le Forest Farm of Zhejiang, Yuhang (China)); Jiang Ping (Zhejiang Provincial Forest Bureau, Hangzhou (China))

    The technical feasibility of the radiopreservation of Antheraea pernyi's eggs, used as the middle hosts of Trichogramma dendrolimi Matsumura, by electron beam is studied in this paper. The results reveal that the preservation time of Antheraea pernyi's eggs irradiated by electron beam, combined with storage in a refrigerator, is prolonged in contrast with the control. When the irradiated eggs stored in a refrigerator for 89 days are serviced as hosts, the percentage for Trichogramma dendrolimi Matsumura emerging is about 80%. Besides, the emergence percentage, the average numbers of parasitoids produced from one egg, as well as body size, growth stage and sexual rte of descendants are all normal. Irradiated host eggs have no adverse effects on the abilities of Trichogramma species and their offspring to control insect pests. (author).

  3. Bioinspired silicification of silica-binding peptide-silk protein chimeras: comparison of chemically and genetically produced proteins.

    Science.gov (United States)

    Canabady-Rochelle, Laetitia L S; Belton, David J; Deschaume, Olivier; Currie, Heather A; Kaplan, David L; Perry, Carole C

    2012-03-12

    Novel protein chimeras constituted of "silk" and a silica-binding peptide (KSLSRHDHIHHH) were synthesized by genetic or chemical approaches and their influence on silica-silk based chimera composite formation evaluated. Genetic chimeras were constructed from 6 or 15 repeats of the 32 amino acid consensus sequence of Nephila clavipes spider silk ([SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQG](n)) to which one silica binding peptide was fused at the N terminus. For the chemical chimera, 28 equiv of the silica binding peptide were chemically coupled to natural Bombyx mori silk after modification of tyrosine groups by diazonium coupling and EDC/NHS activation of all acid groups. After silica formation under mild, biomaterial-compatible conditions, the effect of peptide addition on the properties of the silk and chimeric silk-silica composite materials was explored. The composite biomaterial properties could be related to the extent of silica condensation and to the higher number of silica binding sites in the chemical chimera as compared with the genetically derived variants. In all cases, the structure of the protein/chimera in solution dictated the type of composite structure that formed with the silica deposition process having little effect on the secondary structural composition of the silk-based materials. Similarly to our study of genetic silk based chimeras containing the R5 peptide (SSKKSGSYSGSKGSKRRIL), the role of the chimeras (genetic and chemical) used in the present study resided more in aggregation and scaffolding than in the catalysis of condensation. The variables of peptide identity, silk construct (number of consensus repeats or silk source), and approach to synthesis (genetic or chemical) can be used to "tune" the properties of the composite materials formed and is a general approach that can be used to prepare a range of materials for biomedical and sensor-based applications. PMID:22229696

  4. Improvements of anticoagulant activities of silk fibroin films with fucoidan

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fucoidan (FC),an effective anticoagulant constituent extracted from brown algae,was introduced into silk fibroin (SF) for improving its blood compatibility.The SF and SF/FC blend films were characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR),X-ray photoelectron spectroscopy (XPS),scanning electron microscopy (SEM) and dynamic contact angle determinator (CA).The in vitro anticoagulant activities of the films were evaluated by activated partial thromboplastin time (APTT),thrombin time (TT) and prothrombin time (PT) measurements.The endothelial cell attachment and proliferation viability on the film were assessed by micropipette aspiration technique and MTT assay,respectively.The testing results indicated that the introduction of FC increased the roughness,hydrophilicity and sulfate component of the film surface without impeding the formation of β-sheet conformation in SF.More important,FC brought excellent anticoagulant activity and better endothelial cell affinity to SF.The SF/FC blend film was hopeful to be used as blood-contacting biomaterials.

  5. Controlling silk fibroin microspheres via molecular weight distribution

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-01

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

  6. Satellite SAR data assessment for Silk Road archaeological prospection

    Science.gov (United States)

    Chen, Fulong; Lasaponara, Rosa; Masini, Nicola; Yang, Ruixia

    2015-04-01

    The development of Synthetic Aperture Radar (SAR) in terms of multi-band, multi-polarization and high-resolution data, favored the application of this technology also in archaeology [1]. Different approaches based on both single and multitemporal data analysis, exploiting the backscattering and the penetration of radar data, have been used for a number of archaeological sites and landscapes [2-5]. Nevertheless, the capability of this technology in archaeological applications has so far not been fully assessed. It lacks a contribution aimed at evaluating the potential of SAR technology for the same study area by using different bands, spatial resolutions and data processing solutions. In the framework of the Chinese-Italian bilateral project "Smart management of cultural heritage sites in Italy and China: Earth Observation and pilot projects", we addressed some pioneering investigations to assess multi-mode (multi-band, temporal, resolution) satellite SAR data (including X-band TerraSAR, C-band Envisat and L-band ALOS PALSAR) in archaeological prospection of the Silk road [6]. The Silk Road, a series of trade and cultural transmission routes connecting China to Europe, is the witness of civilization and friendship between the East and West dated back to 2000 years ago, that left us various relics (e.g. lost cities) to be uncovered and investigated.. In particular, the assessment has been performed in the Xinjiang and Gansu section pf the Silk Road focusing on : i) the subsurface penetration capability of SAR data in the arid and semi-arid region ii) and sensitivity of SAR imaging geometry for the detection of relics As regards the point i) , apart from the soil moisture, the penetration is seriously restricted by the soil porosity. For instance, negligible penetration signs were detected in Yumen Frontier Pass either using X- or L-band SAR data due to the occurrence of Yardang landscape. As regards the point ii), the flight path of SAR images in parallel with the

  7. 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.

  8. Fabrication of silk fibroin nanoparticles for controlled drug delivery

    International Nuclear Information System (INIS)

    A novel solution-enhanced dispersion by supercritical CO2 (SEDS) was employed to prepare silk fibroin (SF) nanoparticles. The resulting SF nanoparticles exhibited a good spherical shape, a smooth surface, and a narrow particle size distribution with a mean particle diameter of about 50 nm. The results of X-ray powder diffraction, thermo gravimetry-differential scanning calorimetry, and Fourier transform infrared spectroscopy analysis of the SF nanoparticles before and after ethanol treatment indicated conformation transition of SF nanoparticles from random coil to β-sheet form and thus water insolubility. The MTS assay also suggested that the SF nanoparticles after ethanol treatment imposed no toxicity. A non-steroidal anti-inflammatory drug, indomethacin (IDMC), was chosen as the model drug and was encapsulated in SF nanoparticles by the SEDS process. The resulting IDMC–SF nanoparticles, after ethanol treatment, possessed a theoretical average drug load of 20%, an actual drug load of 2.05%, and an encapsulation efficiency of 10.23%. In vitro IDMC release from the IDMC–SF nanoparticles after ethanol treatment showed a significantly sustained release over 2 days. These studies of SF nanoparticles indicated the suitability of the SF nanoparticles prepared by the SEDS process as a biocompatible carrier to deliver drugs and also the feasibility of using the SEDS process to reach the goal of co-precipitation of drug and SF as composite nanoparticles for controlled drug delivery.

  9. Silk fibroin and sodium alginate blend: Miscibility and physical characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Agostini de Moraes, Mariana; Silva, Mariana Ferreira; Weska, Raquel Farias; Beppu, Marisa Masumi, E-mail: beppu@feq.unicamp.br

    2014-07-01

    Films of silk fibroin (SF) and sodium alginate (SA) blends were prepared by solution casting technique. The miscibility of SF and SA in those blends was evaluated and scanning electron microscopy (SEM) revealed that SF/SA 25/75 wt.% blends underwent microscopic phase separation, resulting in globular structures composed mainly of SF. X-ray diffraction indicated the amorphous nature of these blends, even after a treatment with ethanol that turned them insoluble in water. Thermal analyses of blends showed the peaks of degradation of pristine SF and SA shifted to intermediate temperatures. Water vapor permeability, swelling capacity and tensile strength of SF films could be enhanced by blending with SA. Cell viability remained between 90 and 100%, as indicated by in vitro cytotoxicity test. The SF/SA blend with self-assembled SF globules can be used to modulate structural and mechanical properties of the final material and may be used in designing high performance wound dressing. - Highlights: • Blend films of fibroin and alginate were prepared with microscopic phase separation; • Self-assembled globular microdomains were mainly composed by fibroin; • It was possible to obtain a film with better mechanical and physical properties; • Blend films of fibroin and alginate represent a novel material in biomaterials field.

  10. Extremal limits and Ba\\~nados-Silk-West effect

    CERN Document Server

    Pradhan, Parthapratim

    2016-01-01

    A fascinating property of extremal Kerr black hole (BH) is that it could be act as a particle accelerator with infinite high center-of-mass (CM) energy \\cite{bsw}. In this note, we would like to discuss about such fascinating result and to point out that this infinite energy at the event horizon comes solely due \\emph{to the singular nature of the extremal limit}. We also show that a non-extremal Kerr BH can \\emph{not} transform into extremal Kerr BH by the Ba\\~{n}ados-Silk-West mechanism. Moreover, we discuss about three possible geometries (near extremal, purely extremal and near horizon of extremal Kerr) of this mechanism. We further prove that near extremal geometry and near horizon geometry, precisely extremal geometry of extremal Kerr BHs are qualitatively different. Near extremal geometry and near horizon geometry gives the CM energy is finite, whereas precisely extremal geometry gives the diverging energy. Thus, we can argue that extremal Kerr BH and non-extremal Kerr BH are quite distinct objects. Fi...

  11. Controlling silk fibroin microspheres via molecular weight distribution

    International Nuclear Information System (INIS)

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K2HPO4–KH2PO4). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications

  12. Overcoming dormancy in seeds of cotton-silk tree

    Directory of Open Access Journals (Sweden)

    Irinaldo Lima do Nascimento

    2012-06-01

    Full Text Available Cotton-silk tree Ceiba glaziovii (kuntze k. Schu belongs to family Bombacaceas and is locally known as barriguda. It is widely used in landscaping and reforestation, neverdeless seed dormancy affects reproduction in this species. The objective of this study was to evaluate the effectiveness of different methods to overcome dormancy in the germination process. Treatments included mechanical scarification with 85-grit sandpaper, chemical scarification with concentrated sulfuric acid for 5, 10, 15 and 20 minutes, physical scarification with hot water at 60°, 70°, 80°and 90° C for one minute, imbibition in distilled water for 24, 48 and 72 hours, oven heating at 65° C for 1, 2, 3 and 4 hours, and a control treatment. Each treatment included four replicates of 25 seeds, using a completely randomized experimental design, and means were compared by the Scott-Knott test at the 5% probability level. Assessed parameters included emergence percentage, emergence rate index, dry matter and length of plants. The most recommended treatments were mechanical scarification, immersion in sulfuric acid for 5, 10 and 15 minutes and immersion in distilled water for 48 hours.

  13. Fluorescent silk cocoon creating fluorescent diatom using a “Water glass-fluorophore ferry”

    Science.gov (United States)

    Kusurkar, Tejas S.; Tandon, Ishita; Sethy, Niroj Kumar; Bhargava, Kalpana; Sarkar, Sabyasachi; Singh, Sushil Kumar; Das, Mainak

    2013-11-01

    Fluorophores are ubiquitous in nature. Naturally occurring fluorophores are exceptionally stable and have high quantum yield. Several natural systems have acquired fluorescent signature due to the presence of these fluorophores. Systematic attempt to harvest these fluorophores from natural systems could reap rich commercial benefit to bio-imaging industry. Silk cocoon biomaterial is one such example of natural system, which has acquired a fluorescent signature. The objective of this study is to develop simple, rapid, commercially viable technique to isolate silk cocoon membrane fluorophores and exploring the possibility of using them as fluorescent dye in bio-imaging. Here, we report an innovative water glass (Na2SiO3) based strategy to isolate the silk cocoon fluorophores. Isolated fluorophore is majorly quercetin derivatives and exhibited remarkable photo- and heat stability. Fluorescence and mass spectrometric analysis confirmed presence of a quercetin derivative. We further used this fluorophore to successfully label the silicate shell of diatom species Nitzschia palea.

  14. Corn Silk (Stigma Maydis in Healthcare: A Phytochemical and Pharmacological Review

    Directory of Open Access Journals (Sweden)

    Shuhaimi Mustafa

    2012-08-01

    Full Text Available Corn silk (Stigma maydis is an important herb used traditionally by the Chinese, and Native Americans to treat many diseases. It is also used as traditional medicine in many parts of the world such as Turkey, United States and France. Its potential antioxidant and healthcare applications as diuretic agent, in hyperglycemia reduction, as anti-depressant and anti-fatigue use have been claimed in several reports. Other uses of corn silk include teas and supplements to treat urinary related problems. The potential use is very much related to its properties and mechanism of action of its plant’s bioactive constituents such as flavonoids and terpenoids. As such, this review will cover the research findings on the potential applications of corn silk in healthcare which include its phytochemical and pharmacological activities. In addition, the botanical description and its toxicological studies are also included.

  15. Application of Purified Lawsone as Natural Dye on Cotton and Silk Fabric

    Directory of Open Access Journals (Sweden)

    Md. Mahabub Hasan

    2015-01-01

    Full Text Available The color which is obtained from the leaves of Henna, that is, Lawsonia inermis L., is used frequently in hair coloring. It is the chemical lawsone that is responsible for the reddish brown color. Its content makes it a substantive dye for dyeing the textile materials. This work concerns with the extraction and purification of natural dyestuff from a plant Lawsonia inermis L. and dyeing of cotton and silk fabric in exhaust dyeing method. The dye portion is isolated from the total extract by column chromatography and is evaluated by dyeing cotton and silk under different dyeing conditions. The color strength and fastness properties of the dye are undertaken by changing mordant and techniques of mordanting. The changes of colors have been noticed by using different types of mordant. The dye exhaustion percentage, wash, rubbing, and light fastness results reveal that the extract of henna can be used for coloration of cotton and silk fabric.

  16. 利用柞蚕蛹繁育白蛾周氏啮小蜂的几项关键技术措施

    Institute of Scientific and Technical Information of China (English)

    宋德胜

    2007-01-01

    柞蚕(antheraea pernyi pupa)蛹是白蛾周氏啮小蜂的最佳中间寄主.近几年利用白蛾周氏啮小蜂(Chouioia cunea)防治美国白蛾(Hyphantria cunea Drury)已取得了很大的成效.本文简要总结了利用柞蚕蛹繁殖白蛾周氏啮小蜂的技术.

  17. Porous CaP/silk composite scaffolds to repair femur defects in an osteoporotic model.

    Science.gov (United States)

    Cheng, Ning; Dai, Jing; Cheng, Xiangrong; Li, Shu'e; Miron, Richard J; Wu, Tao; Chen, Wenli; Zhang, Yufeng; Shi, Bin

    2013-08-01

    The most common complication for patients with postmenopausal osteoporosis is bone-related defects and fractures. While routine medication has a high probability of undesirable side effects, new approaches have aimed to develop regeneration procedures that stimulate new bone formation while reversing bone loss. Recently, we have synthesized a new hybrid CaP/silk scaffold with a CaP-phase distribution and pore architecture better suited to facilitate cell differentiation and bone formation. The aim of the present study was to compare the involved remodeling process and therapeutic effect of porous CaP/silk composite scaffolds upon local implantation into osteoporotic defects. Wistar rats were used to induce postmenopausal osteoporotic model by bilateral ovariectomy. The pure silk and hybrid CaP/silk scaffolds were implanted into critical sized defects created in distal femoral epiphysis. After 14 and 28 days, the in vivo osteogenetic efficiency was evaluated by μCT analysis, hematoxylin and eosin staining, Safranin O staining, tartrate-resistant acid phosphatase staining, and immunohistochemical assessment. Animals with or without critical-sized defects were used as drill or blank controls, respectively. The osteoporotic defect model was well established with significantly decreased μCT parameters of BV/TV, Tb.N and increased Tb.Sp, porosity, combined with changes in histological observations. During the healing process, the critical-sized drill control defects failed to regenerate appreciable bone tissue, while more significantly increased bone formation and mineralization with dynamic scaffold degradation and decreased osteoclastic bone resorption could be detected within defects with hybrid CaP/silk scaffolds compared to pure silk scaffolds. PMID:23674058

  18. Efficacy of Silk Channel Injections with Insecticides for Management of Lepidoptera Pests of Sweet Corn.

    Science.gov (United States)

    Sparks, A N; Gadal, L; Ni, X

    2015-08-01

    The primary Lepidoptera pests of sweet corn (Zea mays L. convar. saccharata) in Georgia are the corn earworm, Helicoverpa zea (Boddie), and the fall armyworm, Spodoptera frugiperda (J. E. Smith). Management of these pests typically requires multiple insecticide applications from first silking until harvest, with commercial growers frequently spraying daily. This level of insecticide use presents problems for small growers, particularly for "pick-your-own" operations. Injection of oil into the corn ear silk channel 5-8 days after silking initiation has been used to suppress damage by these insects. Initial work with this technique in Georgia provided poor results. Subsequently, a series of experiments was conducted to evaluate the efficacy of silk channel injections as an application methodology for insecticides. A single application of synthetic insecticide, at greatly reduced per acre rates compared with common foliar applications, provided excellent control of Lepidoptera insects attacking the ear tip and suppressed damage by sap beetles (Nitidulidae). While this methodology is labor-intensive, it requires a single application of insecticide at reduced rates applied ∼2 wk prior to harvest, compared with potential daily applications at full rates up to the day of harvest with foliar insecticide applications. This methodology is not likely to eliminate the need for foliar applications because of other insect pests which do not enter through the silk channel or are not affected by the specific selective insecticide used in the silk channel injection, but would greatly reduce the number of applications required. This methodology may prove particularly useful for small acreage growers. PMID:26470329

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

    Science.gov (United States)

    Ayutsede, Jonathan Eyitouyo

    In recent years, there has been significant interest in the utilization of natural materials for novel nanoproducts such as tissue engineered scaffolds. Silkworm silk fibers represent one of the strongest natural fibers known. Silkworm silk, a protein-based natural biopolymer, has received renewed interest in recent years due to its unique properties (strength, toughness) and potential applications such as smart textiles, protective clothing and tissue engineering. The traditional 10--20 mum diameter, triangular-shaped Bombyx mori fibers have remained unchanged over the years. However, in our study, we examine the scientific implication and potential applications of reducing the diameter to the nanoscale, changing the triangular shape of the fiber and adding nanofillers in the form of single wall carbon nanotubes (SWNT) by the electrospinning process. The electrospinning process preserves the natural conformation of the silk (random and beta-sheet). The feasibility of changing the properties of the electrospun nanofibers by post processing treatments (annealing and chemical treatment) was investigated. B. mori silk fibroin solution (formic acid) was successfully electrospun to produce uniform nanofibers (as small as 12 nm). Response Surface Methodology (RSM) was applied for the first time to experimental results of electrospinning, to develop a processing window that can reproduce regenerated silk nanofibers of a predictable size (d nature of the silk-SWNT interactions. A new visualization system was developed to characterize the transport properties of the nanofibrous assemblies. The morphological, chemical, structural and mechanical properties of the nanofibers were determined by field emission environmental scanning microscopy, Fourier transform infrared and Raman spectroscopy, wide angle x-ray diffraction and microtensile tester respectively.

  20. The Widespread Prevalence and Functional Significance of Silk-Like Structural Proteins in Metazoan Biological Materials.

    Directory of Open Access Journals (Sweden)

    Carmel McDougall

    Full Text Available In nature, numerous mechanisms have evolved by which organisms fabricate biological structures with an impressive array of physical characteristics. Some examples of metazoan biological materials include the highly elastic byssal threads by which bivalves attach themselves to rocks, biomineralized structures that form the skeletons of various animals, and spider silks that are renowned for their exceptional strength and elasticity. The remarkable properties of silks, which are perhaps the best studied biological materials, are the result of the highly repetitive, modular, and biased amino acid composition of the proteins that compose them. Interestingly, similar levels of modularity/repetitiveness and similar bias in amino acid compositions have been reported in proteins that are components of structural materials in other organisms, however the exact nature and extent of this similarity, and its functional and evolutionary relevance, is unknown. Here, we investigate this similarity and use sequence features common to silks and other known structural proteins to develop a bioinformatics-based method to identify similar proteins from large-scale transcriptome and whole-genome datasets. We show that a large number of proteins identified using this method have roles in biological material formation throughout the animal kingdom. Despite the similarity in sequence characteristics, most of the silk-like structural proteins (SLSPs identified in this study appear to have evolved independently and are restricted to a particular animal lineage. Although the exact function of many of these SLSPs is unknown, the apparent independent evolution of proteins with similar sequence characteristics in divergent lineages suggests that these features are important for the assembly of biological materials. The identification of these characteristics enable the generation of testable hypotheses regarding the mechanisms by which these proteins assemble and direct the

  1. The Widespread Prevalence and Functional Significance of Silk-Like Structural Proteins in Metazoan Biological Materials

    Science.gov (United States)

    McDougall, Carmel; Woodcroft, Ben J.

    2016-01-01

    In nature, numerous mechanisms have evolved by which organisms fabricate biological structures with an impressive array of physical characteristics. Some examples of metazoan biological materials include the highly elastic byssal threads by which bivalves attach themselves to rocks, biomineralized structures that form the skeletons of various animals, and spider silks that are renowned for their exceptional strength and elasticity. The remarkable properties of silks, which are perhaps the best studied biological materials, are the result of the highly repetitive, modular, and biased amino acid composition of the proteins that compose them. Interestingly, similar levels of modularity/repetitiveness and similar bias in amino acid compositions have been reported in proteins that are components of structural materials in other organisms, however the exact nature and extent of this similarity, and its functional and evolutionary relevance, is unknown. Here, we investigate this similarity and use sequence features common to silks and other known structural proteins to develop a bioinformatics-based method to identify similar proteins from large-scale transcriptome and whole-genome datasets. We show that a large number of proteins identified using this method have roles in biological material formation throughout the animal kingdom. Despite the similarity in sequence characteristics, most of the silk-like structural proteins (SLSPs) identified in this study appear to have evolved independently and are restricted to a particular animal lineage. Although the exact function of many of these SLSPs is unknown, the apparent independent evolution of proteins with similar sequence characteristics in divergent lineages suggests that these features are important for the assembly of biological materials. The identification of these characteristics enable the generation of testable hypotheses regarding the mechanisms by which these proteins assemble and direct the construction of

  2. Recycled Polyamide-6/Waste Silk & Cotton Fibre Polymer Composites:Effect of Fibre length

    OpenAIRE

    TAŞDEMİR, Münir; KOÇAK, Dilara; MERDAN, Nigar; USTA, İsmail; AKALIN, Mehmet

    2013-01-01

    Among textile fibres today, cotton is the most commonly used natural fibre. Cotton is being used in almost all areas of textiles. Waste cotton which is produced during the yarn production process is then re-used in yarn production again or as a waste in other uses. Besides this, silk fibres have been used for nearly 5000 years. Silk is one of the most precious fibres among all textile fibres and it has a very wide range of uses like: sewing threads, clothes, home textiles, technical textiles ...

  3. Nanomechanics of silk: the fundamentals of a strong, tough and versatile material

    Science.gov (United States)

    Su, Isabelle; Buehler, Markus J.

    2016-07-01

    Spider silk is a remarkable material that provides a template for upscaling molecular properties to the macroscale. In this article we review fundamental aspects of the mechanisms behind these behaviors, discuss the molecular makeup, chemical designs, and how these integrate in a complex arrangement to form webs, cocoons and other material architectures. Moreover, this review paper explores the unique ability of silk to tolerate various kinds of defects, in a way enabling this material platform to serve as one of the most resilient materials in nature. We conclude the discussion with a summary of key scaling laws, an attempt model and define hierarchical length-scales, and the translation to synthetic materials.

  4. Study of the behaviour of silk pongee used for the consolidation of historical textiles

    OpenAIRE

    ARBUES FANDOS, NATALIA CONCEPCIÓN; Bonet Aracil, María Angeles; Yusa Marco, Dolores Julia; MONLLOR PÉREZ Pablo; Vicente Palomino, Sofía

    2010-01-01

    Consolidation is one of the most delicate and decisive process to preserve any fabric. The addition of new sewed fabrics such as `silk pongee¿ to the original textiles is a common practice nowadays to consolidate, reinforce and compensate losses in historic textiles. Pongee is a plane weave silk used as reinforcement fabric due to its low density of the yarns in both the weft and warp directions that provides a considerable transparency as well. Results obtained from this research focus on th...

  5. Earliest tea as evidence for one branch of the Silk Road across the Tibetan Plateau

    Science.gov (United States)

    Lu, Houyuan; Zhang, Jianping; Yang, Yimin; Yang, Xiaoyan; Xu, Baiqing; Yang, Wuzhan; Tong, Tao; Jin, Shubo; Shen, Caiming; Rao, Huiyun; Li, Xingguo; Lu, Hongliang; Fuller, Dorian Q.; Wang, Luo; Wang, Can; Xu, Deke; Wu, Naiqin

    2016-01-01

    Phytoliths and biomolecular components extracted from ancient plant remains from Chang’an (Xi’an, the city where the Silk Road begins) and Ngari (Ali) in western Tibet, China, show that the tea was grown 2100 years ago to cater for the drinking habits of the Western Han Dynasty (207BCE-9CE), and then carried toward central Asia by ca.200CE, several hundred years earlier than previously recorded. The earliest physical evidence of tea from both the Chang’an and Ngari regions suggests that a branch of the Silk Road across the Tibetan Plateau, was established by the second to third century CE.

  6. Silk Road 2.0 - A Study of Cryptomarkets in a Deleuze-Guattarian Perspective

    OpenAIRE

    Bakken, Silje Anderdal

    2015-01-01

    Over the last few years, Internet has been established as a place for drug markets to expand into a new reality and develop according to new business opportunities. Silk Road is one of many cryptomarkets that have succeeded online, offering a wide selection of drugs on global level. This thesis deals with the structural aspect of Silk Road and how it is organized, with theories of Gilles Deleuze and Felix Guattari as a theoretical perspective to catch the complexity. Data has been collected t...

  7. Laser-Induced Fluorescence and Optical Reflection Spectra of Japanese Natural Dyes on Silk

    Science.gov (United States)

    Miyoshi, Tadaki; Matsuda, Yasunori

    1987-02-01

    Fluorescence spectra under nitrogen-laser excitation were measured for silk cloth dyed with Japanese natural dyes. An identification of the dyes on silk was carried out using a laser-induced fluorescence (LIF) technique since dyed cloth has a characteristic fluorescence spectra. Moreover, it is possible to identify dyes on faded cloth and on cloth prepared by a combination dyeing using two kinds of dyes. The LIF technique can identify dyes on cloth which is difficult to identify using the reflection spectral method.

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

    International Nuclear Information System (INIS)

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

  9. Personal use, social supply or redistribution? Cryptomarket demand on Silk Road 2 and Agora

    DEFF Research Database (Denmark)

    Demant, Jakob Johan; Munksgaard, Rasmus; Houborg, Esben

    2016-01-01

    In 2011, Silk Road became the first black market, or "cryptomarket", for illicit drugs. This study examines two of the largest cryptomarkets which have operated, Silk Road 2.0 and Agora Marketplace. We hypothesize that cryptomarkets cater to buyers who intend to resell or redistribute the products...... 2.0 and Agora Marketplace. The results suggest that cryptomarkets resemble traditional drug markets in terms of the distribution and revenues. As such, it is relevant to include cryptomarkets in discussions about potential reductions of the harmful social consequences of drug markets, as well...... as in general discussions about drug markets and drug trafficking....

  10. Structural characterization of a variety of spider silks from Turkey using different biophysical techniques

    OpenAIRE

    İDE, Semra; Bayarı, Sevgi Haman; TÜRKEŞ, Tuncay; Mergen, Y. Orhan; Çelik, Ömer; Bütün, Vural; Sargon, Mustafa F; Kocatepe, Neslihan; Kriechbaum, Manfred

    2011-01-01

    Various experimental methods (XRD, FTIR, SAXS, DLS and SEM) were used to investigate structures of the silk samples weaved by spiders in Turkey. Silk samples were collected from the natural habitats belonging to the spider species (i.e., Near Salt Lake/şereflikoçhisar, İvriz Dam/Ereǧli-Konya, Karataş Lake/Burdur and several locations in Black Sea Region of Turkey). Among all collected species, Araneidae (Araneus angulatus, Argiope bruennichi, Argiope lobata, Larinoides cornutus), Eresidae (Er...

  11. Identification of Wet-Spinning and Post-Spin Stretching Methods Amenable to Recombinant Spider Aciniform Silk.

    Science.gov (United States)

    Weatherbee-Martin, Nathan; Xu, Lingling; Hupe, Andre; Kreplak, Laurent; Fudge, Douglas S; Liu, Xiang-Qin; Rainey, Jan K

    2016-08-01

    Spider silks are outstanding biomaterials with mechanical properties that outperform synthetic materials. Of the six fibrillar spider silks, aciniform (or wrapping) silk is the toughest through a unique combination of strength and extensibility. In this study, a wet-spinning method for recombinant Argiope trifasciata aciniform spidroin (AcSp1) is introduced. Recombinant AcSp1 comprising three 200 amino acid repeat units was solubilized in a 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)/water mixture, forming a viscous α-helix-enriched spinning dope, and wet-spun into an ethanol/water coagulation bath allowing continuous fiber production. Post-spin stretching of the resulting wet-spun fibers in water significantly improved fiber strength, enriched β-sheet conformation without complete α-helix depletion, and enhanced birefringence. These methods allow reproducible aciniform silk fiber formation, albeit with lower extensibility than native silk, requiring conditions and methods distinct from those previously reported for other silk proteins. This provides an essential starting point for tailoring wet-spinning of aciniform silk to achieve desired properties. PMID:27387592

  12. Silk moths in Madagascar: A review of biology, uses and challenges related to Borocera cajani (Vinson, 1863 (Lepidoptera: Lasiocampidae

    Directory of Open Access Journals (Sweden)

    Razafimanantsoa, TM.

    2012-01-01

    Full Text Available Borocera cajani or "Landibe" (vernacular name is the wild silk moth that is currently used to produce silk textiles in Madagascar. This species is endemic to Madagascar, and is distributed throughout the island, colonizing the Uapaca bojeri or "Tapia" forest of the central highlands. The forest provides food in the form of plants for B. cajani, including U. bojeri leaves. The species secretes silk at the onset of pupation and for making cocoons. Borocera cajani and its natural habitat are threatened by human destruction, such as bush fires, firewood collection, charcoal production, and the over-harvesting of their cocoons. Wild silk production largely disappeared when the silk industry utilized many people on the island as the collectors of cocoons, spinners, dyers, weavers, and artists who transform the silk into clothes, accessories, and objects. Therefore, it is important to study the biology of B. cajani to revitalize silk production in a way that helps conserve this species and the Tapia forest.

  13. Genome editing of BmFib-H gene provides an empty Bombyx mori silk gland for a highly efficient bioreactor.

    Science.gov (United States)

    Ma, Sanyuan; Shi, Run; Wang, Xiaogang; Liu, Yuanyuan; Chang, Jiasong; Gao, Jie; Lu, Wei; Zhang, Jianduo; Zhao, Ping; Xia, Qingyou

    2014-01-01

    Evolution has produced some remarkable creatures, of which silk gland is a fascinating organ that exists in a variety of insects and almost half of the 34,000 spider species. The impressive ability to secrete huge amount of pure silk protein, and to store proteins at an extremely high concentration (up to 25%) make the silk gland of Bombyx mori hold great promise to be a cost-effective platform for production of recombinant proteins. However, the extremely low production yields of the numerous reported expression systems greatly hindered the exploration and application of silk gland bioreactors. Using customized zinc finger nucleases (ZFN), we successfully performed genome editing of Bmfib-H gene, which encodes the largest and most abundant silk protein, in B. mori with efficiency higher than any previously reported. The resulted Bmfib-H knocked-out B. mori showed a smaller and empty silk gland, abnormally developed posterior silk gland cells, an extremely thin cocoon that contain only sericin proteins, and a slightly heavier pupae. We also showed that removal of endogenous Bmfib-H protein could significantly increase the expression level of exogenous protein. Furthermore, we demonstrated that the bioreactor is suitable for large scale production of protein-based materials. PMID:25359576

  14. Microorganisims in Fermented Bio-extract from Irradiated Silk Waste

    International Nuclear Information System (INIS)

    Microbiological characteristics of four samples of bio-extract from gamma irradiated (300 kGy) silk waste fermented for 0, 1, 2, 3 and 4 months were investigated. The results revealed that total bacterial counts in all samples of bio-extract were initially found to be 2.32*107 - 1.69*108 cfu/ml. Four months later, total bacterial counts mainly decreased according to the fermentation time. At the beginning, lactic acid bacteria were found in three samples and ranged from 6.0*106-2.2*108 cfu/ml. Only in one sample that lactic acid bacteria were not found. Four months later, lactic acid bacteria were still found in two samples and ranged from 1.8*102-3.8*107 cfu/ml. Initially, total yeasts were found in all samples and ranged from 1.0*104-3.2*105 cfu/ml which exceeded the standard value of domestic products. In the fourth month, total yeasts were not found in three samples. However, they were found in one sample and still exceeded the standard value of domestic products. Three pathogenic bacteria namely Salmonella spp., Staphylococcus aureus and Clostridium perfringens were not found in any samples after any fermentation length, indicating that the samples were up to standard level of domestic products. At zero month, all samples were contaminated with the Most Probable Number (MPN) of Escherichia coli in the range of 15 - >1.1*103 cfu/ml and exceeded the standard value. However, one month later the MPN of E. coli were not found in all samples and therefore the samples were up to the standard level of domestic products.

  15. 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.

  16. Spray drying as a method of producing silk sericin powders

    Directory of Open Access Journals (Sweden)

    G. Genç

    2009-11-01

    Full Text Available Purpose: The purpose of paper is to analyse Spray drying as a method of producing silk sericin powders.Design/methodology/approach: Aqueous sericin solutions were used as raw material for the production of dry powders using a lab-scale spray dryer. A linear regression analysis of agglomeration was employed, in addition to experimental designs at two levels with three factors for the analysis of three responses: moisture content, particle type and agglomeration degree. The process factors were the drying air temperature (120ºC and 160ºC, the feed rate (1.25 × 10-7 and 2.5 × 10-7 m³/s, and the concentration of sericin solutions of 10% and 30% (w/w fed to the spray dryer.Findings: The three responses were analyzed statistically to determine the effective parameters and it was concluded that moisture content depended on three factors--drying air temperature being the dominant parameter. Particle size and shape depended mainly on feed rate and agglomeration depended on the moisture content of the product.Practical implications: As a result of the growing interest in drug delivery through a pulmonary route for local and systemic effects, the crucial physical characteristics of the spray-dried sericin influencing the dispersion and deposition behaviour including particle size, morphology, moisture content and agglomeration degree were examined for formulation and spray drying variables.Originality/value: The most effective parameters on particle size and morphology were found to be the feed solution concentration and feed rate, while the temperature was an insignificant variable.

  17. Genome editing of BmFib-H gene provides an empty Bombyx mori silk gland for a highly efficient bioreactor

    OpenAIRE

    Ma, Sanyuan; Shi, Run; Wang, Xiaogang; Liu, Yuanyuan; Chang, Jiasong; Gao, Jie; Lu, Wei; Zhang, Jianduo; ZHAO, PING; Xia, Qingyou

    2014-01-01

    Evolution has produced some remarkable creatures, of which silk gland is a fascinating organ that exists in a variety of insects and almost half of the 34,000 spider species. The impressive ability to secrete huge amount of pure silk protein, and to store proteins at an extremely high concentration (up to 25%) make the silk gland of Bombyx mori hold great promise to be a cost-effective platform for production of recombinant proteins. However, the extremely low production yields of the numerou...

  18. Impact of applying edible oils to silk channels on ear pests of sweet corn

    Science.gov (United States)

    The impact of applying vegetable oils to corn silks on ear-feeding insects in sweet corn production was evaluated in 2006 and 2007. Six vegetable oils used in this experiment were canola, corn, olive, peanut, sesame, and soybean. Water and two commercial insecticidal oils (Neemix' neem oil and Sun...

  19. POSITRON LIFETIME STUDY OF THERMALLY INDUCED MICROSTRUCTURAL CHANGES IN NISTARI SILK FIBER

    Institute of Scientific and Technical Information of China (English)

    C. Ranganathaiah

    2003-01-01

    Positron lifetime measurements have been made in natural polymer-Nistari silk fibers as a function of isochronal annealing temperature in the range of 27℃ to 280℃. The variations in the positron results indicate the structural changes occurring in the Nistari silk fibers and determine the glass transition temperature as 170℃. Activation energies were measured separately for the crystalline and amorphous regions indicating the versatility of the technique. These values are close to the N-H bond dissociation energy, suggesting N-H bond dissociation as the most probable process occurring during thermal treatment. As an extension of the positron results, the molecular weight of the Nistari silk fibers was determined to be 10.7 × 105 based on free volume, which lies within the range suggested for the silk fibers. There seems to be an indication that cross-linking changes the spiral structure of cotton fibers to network type. However, this needs to be validated by other techniques.

  20. Dyeing of Silk with Anthocyanins Dyes Extract from Liriope platyphylla Fruits

    Directory of Open Access Journals (Sweden)

    Huayin Wang

    2014-01-01

    Full Text Available A new source of natural anthocyanins dyes, from Liriope platyphylla fruit, is proposed. This paper analyzes the dye extracts, the primary color components of the extracts, the color features of the extracts under different pH conditions, and their application in silk dyeing. The research shows that, nine anthocyanins are found in  L. platyphylla fruits by analyzing the results of the HPLC/DAD, MS, and MS/MS spectra. The five major anthocyanins related to delphinidin, petunidin, and malvidin derivatives take up 91.72% of total anthocyanin contents. The color of the solution is red under acidic condition (pH < 3.0 and stays in yellow under alkaline condition with pH values above 7.0. The dye extracts applied to silk fabric with mordant free dyeing show different color under different pH conditions, changing between purple, blue, green, and yellow. However, the dyed colors is light and the dyeing rate is low. Metal mordant such as Sn in chelation enhances the dye depth and improves the fastness of the dyed silk fabrics, especially in silk fabrics dyed by premordanting and metamordanting.

  1. Conization of the cervix uteri. Complications in connection with plain catgut or silk suturing

    DEFF Research Database (Denmark)

    Holmskov, A; Qvist, N; Møller, A

    1984-01-01

    During a retrospective study on postoperative complications in 213 patients who had undergone conization, a (non-significant) reduction in the bleeding rate from 27.9% to 18.6% was found when using silk sutures (102 patients) instead of plain catgut (111 patients) for adaption of the edges of the...

  2. INTRODUCTORY BACKGROUND FOR LIFE CYCLE ASSESSMENT (LCA OF PURE SILK FABRIC

    Directory of Open Access Journals (Sweden)

    Silvia Mara Bortoloto Damasceno Barcelos

    2013-06-01

    Full Text Available The main goal of this study is to provide an introductory background to development of the Life Cycle Assessment studies of pure silk fabric. There are not studies available on the life cycle of pure silk fabric. In this sense, was developed a scenario model for LCA application, following the methodology established by the Standard BNR ISO 14040:2009, which establishes principles and framework for an LCA study. It was considered one of the first steps in ISO, being the definition of the purpose and scope. The limits considered for the system had as a starting point the wiring step within the company, and as a final limit the stage of the finishing of the fabric, where you get the finished product. The information used in this study was collected directly from the company entitled 'Fio de Seda', a Brazilian industry. In order to construct the scenario proposed, was used the software Umberto® 5.6 v. Acad and through it, it was possible to generate the scenario model for the production of the silk fabric. Based on this scenario, the accomplishment of the later stages is possible, as outlined in ISO 14040, thus obtaining the inventory of the LCA for the pure silk fabric, as well as its life cycle inventory assessment.

  3. Treatment of intracranial aneurysms. Reconstruction of the parent artery with flow-diverting (Silk) stent

    DEFF Research Database (Denmark)

    Wagner, Aase; Cortsen, Marie; Hauerberg, John; Romner, Bertil; Wagner, Mathias Pedersen

    2011-01-01

    periprocedural complications, immediate result, late complications, imaging follow-up at 6 and 12 months and clinical follow-up at 2-23 months. METHODS: Twenty-two patients with 26 wide-necked or blister-like aneurysms had 23 treatments with implantation of a Silk stent. Eleven patients had re-canalizations, and...

  4. Determination of molecular markers associated with anthesis-silking interval in maize

    International Nuclear Information System (INIS)

    Maize lines contrasting in anthesis-silking, interval (ASI), a trait strongly linked to drought tolerance, have been analyzed under different water stress conditions in the field and with molecular markers. Correlation of marker and field data has revealed molecular markers strongly associated with flowering and yield traits. (author)

  5. Development and silk production by silkworm larvae after topical application of methoprene

    Directory of Open Access Journals (Sweden)

    Miranda José Ednilson

    2002-01-01

    Full Text Available Juvenile hormone analogues have been tested as insect growth regulators in silkworm (Bombyx mori, seeking an increment of silk production. These chemical products, when applied in small or moderate rates, promote the extension of the last larval instar. To understand the physiologic consequences on silk production by the silkworm strain C115 x N108, the application of methoprene, a juvenile hormone analogue, was performed to evaluate its effects on larval development and silk production. Methoprene was topically applied 48h after the fourth larval ecdysis, on the dorsal integument of the 2nd thoracic segment of the insects, at seven rates between 0 and 20 ng a.i. Methoprene influenced positively the duration of the fifth instar and the weight gain of the insects. The application of 1ng methoprene resulted in the heaviest silkglands, cocoons, shell cocoons and pupae weights. Comparatively to the control, the increment on silk production (approximately 24% by the use of 1ng methoprene was more accentuated than the corresponding negative effects on the cocooning rate (approximately 12%.

  6. THE USE OF NEAR INFRARED SPECTROSCOPY AS A DIAGNOSTIC TOOL FOR HISTORIC SILK ARTEFACTS

    Directory of Open Access Journals (Sweden)

    Paul Garside

    2009-01-01

    Full Text Available As a prestigious and expensive textile, silk is found in manyhistoric artefacts of cultural importance. However, as silkages it becomes increasingly fragile and thus prone to damagethrough handling, display or even conservation treatment;these problems are exacerbated by some of the processingmethods traditionally applied to such materials.Therefore, in order to minimise the danger to these objects,it is vital to have a good understanding of the physical stateof the silk component. It is shown that near infrared spectroscopy,in combination with multivariate analysis, providesa method of assessing the stresses within a silk artefact,thereby highlighting areas at particular risk and allowinginformed decisions to be made as to the potential dangersof intervention. As near infrared spectroscopy mayreadily be used with a fibre optic probe, these analyses canbe performed in situ, rapidly and in a non-invasive manner,thus allowing assessment to be carried out in collectionsand displays without requiring samples to be taken, limitingthe disturbance to artefacts. Therefore, the technique providesa valuable tool to gain a practical understanding ofthe condition of silk artefacts, and a means of informingconservation, display and storage strategies.

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

    International Nuclear Information System (INIS)

    Natural polymer blend films composed of chitosan and silk fibroin were prepared by varying the ratio of chitosan to silk fibroin, with and without glutaraldehyde as a crosslinking agent. The effects of the ratio of chitosan to silk fibroin and crosslinking agent on swelling behavior of the blend films were studied. For the swelling behavior, the blend films exhibited a dramatic change in the degree of swelling when immersed in acidic solutions. The degree of swelling of the films increased as the chitosan content increased; the blend film with 80% chitosan content had the maximum degree of swelling. It appeared that crosslinking had occurred in the blend films which helped the films to retain their three dimensional structure. In addition, FTIR spectra of the films showed evidence of hydrogen bonding interaction between chitosan and silk fibroin. For the effect of salt type, the films were immersed in various types of aqueous salt solutions, viz NaCl, LiCl, CaCl2, AlCl3, and FeCl3. The films immersed in AlCl3 and FeCl3 aqueous solutions gave the maximum degree of swelling. The effects of AlCl3 and FeCl3 concentrations on swelling behavior were also investigated. It was found that the maximum degree of swelling of the films occurred at 1.0 x 10-2 M of AlCl3 and FeCl3 aqueous solutions. (author)

  8. Effects of sterilization methods on the physical, chemical, and biological properties of silk fibroin membranes.

    Science.gov (United States)

    de Moraes, Mariana Agostini; Weska, Raquel Farias; Beppu, Marisa Masumi

    2014-05-01

    Silk fibroin has been widely explored for many biomedical applications, due to its biocompatibility and biodegradability. Sterilization is a fundamental step in biomaterials processing and it must not jeopardize the functionality of medical devices. The aim of this study was to analyze the influence of different sterilization methods in the physical, chemical, and biological characteristics of dense and porous silk fibroin membranes. Silk fibroin membranes were treated by several procedures: immersion in 70% ethanol solution, ultraviolet radiation, autoclave, ethylene oxide, and gamma radiation, and were analyzed by scanning electron microscopy, Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction, tensile strength and in vitro cytotoxicity to Chinese hamster ovary cells. The results indicated that the sterilization methods did not cause perceivable morphological changes in the membranes and the membranes were not toxic to cells. The sterilization methods that used organic solvent or an increased humidity and/or temperature (70% ethanol, autoclave, and ethylene oxide) increased the silk II content in the membranes: the dense membranes became more brittle, while the porous membranes showed increased strength at break. Membranes that underwent sterilization by UV and gamma radiation presented properties similar to the nonsterilized membranes, mainly for tensile strength and FTIR results. PMID:24259492

  9. Silk as a biocohesive sacrificial binder in the fabrication of hydroxyapatite load bearing scaffolds.

    Science.gov (United States)

    McNamara, Stephanie L; Rnjak-Kovacina, Jelena; Schmidt, Daniel F; Lo, Tim J; Kaplan, David L

    2014-08-01

    Limitations of current clinical methods for bone repair continue to fuel the demand for a high strength, bioactive bone replacement material. Recent attempts to produce porous scaffolds for bone regeneration have been limited by the intrinsic weakness associated with high porosity materials. In this study, ceramic scaffold fabrication techniques for potential use in load-bearing bone repairs have been developed using naturally derived silk from Bombyx mori. Silk was first employed for ceramic grain consolidation during green body formation, and later as a sacrificial polymer to impart porosity during sintering. These techniques allowed preparation of hydroxyapatite (HA) scaffolds that exhibited a wide range of mechanical and porosity profiles, with some displaying unusually high compressive strength up to 152.4 ± 9.1 MPa. Results showed that the scaffolds exhibited a wide range of compressive strengths and moduli (8.7 ± 2.7 MPa to 152.4 ± 9.1 MPa and 0.3 ± 0.1 GPa to 8.6 ± 0.3 GPa) with total porosities of up to 62.9 ± 2.7% depending on the parameters used for fabrication. Moreover, HA-silk scaffolds could be molded into large, complex shapes, and further machined post-sinter to generate specific three-dimensional geometries. Scaffolds supported bone marrow-derived mesenchymal stem cell attachment and proliferation, with no signs of cytotoxicity. Therefore, silk-fabricated HA scaffolds show promise for load bearing bone repair and regeneration needs. PMID:24881027

  10. In the Mountain's Shadow:Japan's Silk Reelers Blazed an Asian Path of Economic Development

    Institute of Scientific and Technical Information of China (English)

    Yoichi Shimatsu

    2004-01-01

    Exploring the history of the silk-reeling industry in Chichibu, Japan, this paper challenges the prevalent representation of mountain communities as marginal economic peripheries of the metropolitan center or as reservoirs of poverty and backwardness. Mountain districts were the cradle of an Asian "industrious" revolution that led to Japan's modernization. The highland-based silk-reeling producers pioneered an autonomous Asian model of industrial development, which competed successfully against the capital-intensive system introduced from the West into coastal cities.The export strength of silk-producing households in upland villages overturns the claim that Japan's economic miracle was based on the introduction of Western technology and administrative systems. To the contrary, the Asian-style management practices and labor standards developed by the silk producers were transferred to a succession of other industries.These indigenous practices account for the rise of Japanese industry in world markets. The clash between the two opposing models of modernization resulted in modern Japan's first major civil conflict,the Chichibu Rebellion of 1884, a legacy that has major implications for today's recession-mired Japan as well as for developing countries striving for an alternative path to economic development.

  11. Temperature-pH Sensitive IPN Hydrogels Composed of Silk Sericin and Poly (N-isopropylacrylamide)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Interpenetrating polymer network (IPN) composed of silk sericin (SS) and poly(N-isopropylacrylamide) (PNIPAAm) was prepared. The morphology of the IPNs, in which the SS phase was stained with ammonium cuprate, was examined with TEM and a relative homogeneous distribution of the two polymers was exhibited. The swelling behavior of the IPN hydrogels showed both temperature and pH dependences.

  12. Spider-silk-like shape memory polymer fiber for vibration damping

    International Nuclear Information System (INIS)

    In this study, the static and dynamic properties of shape memory polyurethane (SMPU) fiber are reported and compared to those of spider dragline silk. Although the polymeric fiber has a lower strength compared to spider dragline silks (0.2–0.3 GPa versus 1.1 GPa), it possesses much higher toughness (276–289 MJ m−3 versus 160 MJ m−3), due to its excellent extensibility. The dynamic mechanical tests reveal that SMPU fiber has a high damping capacity (tan δ = 0.10–0.35) which is comparable to or even higher than that of spider silks (tan δ = 0.15). In addition, we found that, different programming methods change the shape memory and damping properties of the fiber in different ways and cold-drawing programming is more advocated in structural applications. These results suggest that the SMPU fiber has similar vibration damping and mechanical properties as spider silk, and may find applications in lightweight engineering structures. (paper)

  13. Structure and post-translational modifications of the web silk protein spidroin-1 from Nephila spiders.

    Science.gov (United States)

    dos Santos-Pinto, José Roberto Aparecido; Lamprecht, Günther; Chen, Wei-Qiang; Heo, Seok; Hardy, John George; Priewalder, Helga; Scheibel, Thomas Rainer; Palma, Mario Sergio; Lubec, Gert

    2014-06-13

    Spidroin-1 is one of the major ampullate silk proteins produced by spiders for use in the construction of the frame and radii of orb webs, and as a dragline to escape from predators. Only partial sequences of spidroin-1 produced by Nephila clavipes have been reported up to now, and there is no information on post-translational modifications (PTMs). A gel-based mass spectrometry strategy with ETD and CID fragmentation methods were used to sequence and determine the presence/location of any PTMs on the spidroin-1. Sequence coverage of 98.06%, 95.05%, and 98.37% were obtained for N. clavipes, Nephila edulis and for Nephila madagascariensis, respectively. Phosphorylation was the major PTM observed with 8 phosphorylation sites considered reliable on spidroin-1 produced by N. clavipes, 4 in N. madagascariensis and 2 for N. edulis. Dityrosine and 3,4-dihydroxyphenylalanine (formed by oxidation of the spidroin-1) were observed, although the mechanism by which they are formed (i.e. exposure to UV radiation or to peroxidases in the major ampullate silk gland) is uncertain. Herein we present structural information on the spidroin-1 produced by three different Nephila species; these findings may be valuable for understanding the physicochemical properties of the silk proteins and moreover, future designs of recombinantly produced spider silk proteins. Biotechnological significance The present investigation shows for the first time spidroin structure and post-translational modifications observed on the major ampullate silk spidroin-1. The many site specific phosphorylations (localized within the structural motifs) along with the probably photoinduction of hydroxylations may be relevant for scientists in material science, biology, biochemistry and environmental scientists. Up to now all the mechanical properties of the spidroin have been characterized without any consideration about the existence of PTMs in the sequence of spidroins. Thus, these findings for major ampullate silk

  14. Towards Silk Fiber Optics: Refractive Index Characterization, Fiber Spinning, and Spinneret Analysis

    Science.gov (United States)

    Spitzberg, Joshua David

    Of the many biologically derived materials, whose historical record of use by humans underscores an ex-vivo utility, silk is interesting for it's contemporary repurposing from textile to biocompatible substrate. And while even within this category silk is one of several materials studied for novel repurposing, it has the unique character of being evolutionarily developed specifically for fiber spinning in vivo. The work discussed here is inspired by taking what nature has given, to explore the in vitro spinning of silk towards biocompatible fiber optics applications. A common formulation of silk used in biomedical studies for re-forming it into the various structures begins with the silkworm cocoon, which is degummed and dissolved into an aqueous solution of its miscible protein, fibroin, and post-treated to fabricate solid structures. In the first aim, the optical refractive index (RI) of various post-treatment methods is discussed towards determining RI design techniques. The methods considered in this work for re-forming a solid fiber from the reconstituted silk fibroin (RSF) solution borrow from the industrial techniques of gel spinning, and dry-spinning. In the second aim, methods are applied to RSF and quality of the spun fibers discussed. A feature common to spinning techniques is passing the (silk) material through a spinneret of specific shape. In the third aim, fluid flow through a simplified native silkworm spinneret is modeled towards bio-inspired lessons in design. In chapter 1 the history, reconstitution, are discussed towards understanding the fabrication of several optical device examples. Chapter 2 then prefaces the experiments and measurements in fiber optics by reviewing electromagnetic theory of waveguide function, and loss factors, to be considered in actual device fabrication. Chapter 3 presents results and discussion for the first aim, understanding design principles for the refractive index of RSF. From this point, industrial fiber

  15. Effect of microgravity on primordial germ cells (PGCs) in silk chicken offspring ( Gallus gallus domesticus)

    Science.gov (United States)

    Zhou, Zhenming; Li, Zandong

    2011-08-01

    Primordial germ cells (PGCs), precursors of germline cells, display a variety of antigens during their migration to target gonads. Here, we used silk chicken offspring ( Gallus gallus domesticus) embryos subjected to space microgravity to investigate the influence of microgravity on PGCs. The ShenZhou-3 unmanned spaceship carried nine fertilized silk chicken eggs, named the flight group, returned to Earth after 7 days space flight. And the control group has the same clan with the flight group. PGCs from flight and control group silk chicken offspring embryos were examined during migration by using two antibodies (2C9 and anti-SSEA-1), in combination with the horseradish peroxidase detection system, and using periodic acid-Schiff's solution (PAS) reaction. After incubation for about 30 h, SSEA-1 and 2C9 positive cells were detected in the germinal crescent of flight and control group silk chicken offspring embryos. After incubation of eggs for 2-2.5 days, SSEA-1 and 2C9 positive cells were detected in embryonic blood vessels of flight and control group silk chicken offspring embryos. After incubation of eggs for 5.5 days, PGCs in the dorsal mesentery and gonad could also be identified in flight and control group silk chicken offspring embryos by using SSEA-1 and 2C9 antibodies. Based on location and PAS staining, these cells were identified as PGCs. Meanwhile, at the stage of PGCs migration and then becoming established in the germinal ridges, no difference in SSEA-1 or 2C9 staining was detected between female and male PGCs in flight and control group silk chicken offspring embryos. Although there were differences in the profiles of PGC concentration between male and female embryos during the special circulating stage, changing profile of PGCs concentration was similar in same sex between flight and control group offspring embryos. We concluded that there is little effect on PGCs in offspring embryos of microgravity-treated chicken and that PGC development appears

  16. 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

    2014-03-01

    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.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

  17. Indigenous silk moth farming as a means to support Ranomafana National Park

    Directory of Open Access Journals (Sweden)

    Catherine L. Craig

    2006-12-01

    Full Text Available We envisage a world where the rural poor can derive a livelihood from protecting forests instead of cutting them down; where development planners understand that habitat health is the keystone for human health and survival, and where conservation biologists understand that long - term solutions to biodiversity loss must be built around social programs which enable local people to thrive. Our vision, however, can only be achieved when scientists express the role of biodiversity conservation in economic terms (Baird and Dearden 2003, and development planners understand environmental complexity and its role in poverty alleviation. Our long - term goal is to develop a generalized approach to biodiversity conservation that will enable scientists and development professionals to identify, plan and initiate sustainable, small - scale businesses in ecologically important areas. This paper reports on a recent study to expand current production of wild silk and explore new types of silk as one economic means of biodiversity protection in Madagascar. Madagascar is one of the most important centers of world biodiversity and 90% of its species are forest dwelling. Nevertheless, 80% of the population are subsistence farmers (Kistler and Spack 2003, and the predominant agricultural practice is “tavy” or slash and burn. Less than 10 % of the original forest remains. Development and conservation communities can effectively prevent deforestation only when they counter the macroeconomic forces that drive people to clear land. Small-scale farmers cut down forests because national and international policies, market conditions or local institutions do not provide them with reasonable alternatives (Tomich et al. 2005. Furthermore, even when alternatives are made available, results are difficult to achieve in a short time. At least some actions need to be implemented pro-actively, in sites that are currently healthy but near areas of potential population growth. We

  18. Chromosome mapping of dragline silk genes in the genomes of widow spiders (Araneae, Theridiidae.

    Directory of Open Access Journals (Sweden)

    Yonghui Zhao

    Full Text Available With its incredible strength and toughness, spider dragline silk is widely lauded for its impressive material properties. Dragline silk is composed of two structural proteins, MaSp1 and MaSp2, which are encoded by members of the spidroin gene family. While previous studies have characterized the genes that encode the constituent proteins of spider silks, nothing is known about the physical location of these genes. We determined karyotypes and sex chromosome organization for the widow spiders, Latrodectus hesperus and L. geometricus (Araneae, Theridiidae. We then used fluorescence in situ hybridization to map the genomic locations of the genes for the silk proteins that compose the remarkable spider dragline. These genes included three loci for the MaSp1 protein and the single locus for the MaSp2 protein. In addition, we mapped a MaSp1 pseudogene. All the MaSp1 gene copies and pseudogene localized to a single chromosomal region while MaSp2 was located on a different chromosome of L. hesperus. Using probes derived from L. hesperus, we comparatively mapped all three MaSp1 loci to a single region of a L. geometricus chromosome. As with L. hesperus, MaSp2 was found on a separate L. geometricus chromosome, thus again unlinked to the MaSp1 loci. These results indicate orthology of the corresponding chromosomal regions in the two widow genomes. Moreover, the occurrence of multiple MaSp1 loci in a conserved gene cluster across species suggests that MaSp1 proliferated by tandem duplication in a common ancestor of L. geometricus and L. hesperus. Unequal crossover events during recombination could have given rise to the gene copies and could also maintain sequence similarity among gene copies over time. Further comparative mapping with taxa of increasing divergence from Latrodectus will pinpoint when the MaSp1 duplication events occurred and the phylogenetic distribution of silk gene linkage patterns.

  19. The formation of collective silk balls in the spider mite Tetranychus urticae Koch.

    Directory of Open Access Journals (Sweden)

    Gwendoline Clotuche

    Full Text Available Tetranychus urticae is a phytophagous mite that forms colonies of several thousand individuals. These mites construct a common web to protect the colony. When plants become overcrowded and food resources become scarce, individuals gather at the plant apex to form a ball composed of mites and their silk threads. This ball is a structure facilitating group dispersal by wind or animal transport. Until now, no quantitative study had been done on this collective form of migration. This is the first attempt to understand the mechanisms that underlie the emergence and growth of the ball. We studied this collective behaviour under laboratory conditions on standardized infested plants. Our results show that the collective displacement and the formation of balls result from a recruitment process: by depositing silk threads on their way up to the plant apex, mites favour and amplify the recruitment toward the balls. A critical threshold (quorum response in the cumulative flow of mites must be reached to observe the emergence of a ball. At the beginning of the balls formation, mites form an aggregate. After 24 hours, the aggregated mites are trapped inside the silk balls by the complex network of silk threads and finally die, except for recently arrived individuals. The balls are mainly composed of immature stages. Our study reconstructs the key events that lead to the formation of silk balls. They suggest that the interplay between mites' density, plant morphology and plant density lead to different modes of dispersions (individual or collective and under what conditions populations might adopt a collective strategy rather than one that is individually oriented. Moreover, our results lead to discuss two aspects of the cooperation and altruism: the importance of Allee effects during colonization of new plants and the importance of the size of a founding group.

  20. Functional expression of a Bombyx mori cocoonase: potential application for silk degumming

    Institute of Scientific and Technical Information of China (English)

    Prangprapai Rodbumrer; Dumrongkiet Arthan; Utai Uyen; Jirundon Yuvaniyama; Jisnuson Svasti; Pramvadee Y.Wongsaengchantra

    2012-01-01

    Cocoon,a shelter for larva development to silk moth,contains the fibrous protein fibroin,which is coated by the globular protein sericin.Emergence of the silk moth requires the action of cocoonase,a protease secreted by the pupa.The full-length prococoonase cDNA,with 780 bp open reading frame encoding 260 amino acids,was cloned by reverse transcription from total RNA of the head of 6-day-old Thai-silk Bombyx mori pupa.Only the gene fragment lacking the propeptide encoding sequence was successfully expressed in Pichia pastoris,yielding an extracellularly active cocoonase.The recombinant cocoonase was purified to homogeneity by 80% ammonium-suffate fractionation and CM-Sepharose chromatography,and its internal peptide sequences were analyzed by nano liquid chromatographymass spectrometry/mass spectrometry.This monomeric protein has native molecular weight of 26 kDa by gel exclusion analysis and 25 kDa subunit size by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.The enzyme hydrolyses sericin but does not hydrolyse fibroin,as shown by radial diffusion on thin-layer enzyme assay (RD-TEA).Scanning electron microscopy showed that purified recombinant cocoonase could remove sericin from natural silk completely in 24 h,without damaging fibroin,using only 1immobilized sericin unit (ISU) of enzyme as determined by RD-TEA.Natural cocoonase isolated from B.mori pupa could also digest sericin effectively,but required more enzymes (2 ISU) and longer time (48 h).In comparison,a commercial enzyme,alcalase,with the same activity not only showed less complete digestion of sericin but also caused damage of fibroin.These results suggest that recombinant B.mori cocoonase is potentially useful for silk degumming.

  1. Nephroprotective effect of Corn Silk extract on oxalic acid-induced nephrocalcinosis in rabbit model

    Directory of Open Access Journals (Sweden)

    Faruk Hassan Al-Jawad

    2012-04-01

    Full Text Available ABSTRACT Background : Nephrocalcinosis is a state of deposition of calcium phosphate or oxalate in the renal parenchyma. It may occur in patients with renal tubular acidosis, vitamin D intoxication, and hyperparathyroidism. Corn silk was used in traditional Chinese medicine to relieve renal pains. Aim: To evaluate the effect of Corn silk aqueous extract in reducing calcium deposits from renal parenchyma in oxalic acid-induced nephrocalcinosis model. Materials and methods: Fourteen healthy rabbits were allocated to two groups. Two hours before induction of nephrocalcinosis, one group received water and the other received aqueous extract of corn silk and continued feeding for ten days. Blood samples were collected for biochemical analysis before induction and in the fifth and tenth post-induction day. Urine samples were taken to estimate urinary ca+2 levels and crystals. The histopathological examination was carried to check for crystal deposits in renal tissues. Results: Corn silk aqueous extract produced a significant reduction of blood urea nitrogen(5.2+/-0.08 vs 7.3+/-0.2 mmol/l, serum creatinine (85.9+/-0.2 vs 97.3+/-0.5 mmol/l and serum Na+ levels (137+/-0.2 vs 142.16+/-0.7 mmol/l with non-significant reduction in serum K+ (4.0+/-0.02 vs 4.2+/-0.05. There is a significant reduction in calcium deposition in renal parenchyma in comparison to the control group after ten days of treatment. Conclusion: Corn silk had a significant diuretic effect that accelerates the excretion of urinary calcium. [J Intercult Ethnopharmacol 2012; 1(2.000: 75-78

  2. Bio-inspired Silicification of Silica-binding Peptide-Silk Protein Chimeras: Comparison of Chemically and Genetically Produced Proteins

    OpenAIRE

    Canabady-Rochelle, Laetitia L.S.; Belton, David J.; Deschaume, Olivier; Currie, Heather A.; Kaplan, David L; Perry, Carole C.

    2012-01-01

    Novel protein chimeras constituted of ‘silk’ and a silica-binding peptide (KSLSRHDHIHHH) were synthesized by genetic or chemical approaches and their influence on silica-silk based chimera composite formation evaluated. Genetic chimeras were constructed from 6 or 15 repeats of the 32 amino acid consensus sequence of Nephila clavipes spider silk ([SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQG]n) to which one silica binding peptide was fused at the N terminus. For the chemical chimera, 25 equivalents of t...

  3. Effects of different post-spin stretching conditions on the mechanical properties of synthetic spider silk fibers

    OpenAIRE

    Albertson, Amy E.; Teulé, Florence; Weber, Warner; Yarger, Jeffery L.; Lewis, Randolph V.

    2013-01-01

    Spider silk is a biomaterial with impressive mechanical properties, resulting in various potential applications. Recent research has focused on producing synthetic spider silk fibers with the same mechanical properties as the native fibers. For this study, three proteins based on the Argiope aurantia Major ampullate Spidroin 2 consensus repeat sequence were expressed, purified and spun into fibers. A number of post-spin draw conditions were tested to determine the effect of each condition on ...

  4. Tuning Molecular Weights of Bombyx mori (B. mori) Silk Sericin to Modify Its Assembly Structures and Materials Formation

    OpenAIRE

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

    2014-01-01

    Bombyx mori (B. mori) silk sericin is a protein with features desirable as a biomaterial, such as increased hydrophilicity and biodegradation, as well as resistance to oxidation, bacteria, and ultraviolet light. In contrast to other widely studied B. mori silk proteins such as fibroin, sericin is still unexplored as a building block for fabricating biomaterial, and thus a facile technique of processing it into a material is needed. Here, electrospinning technology was used to fabricate it int...

  5. Exploring natural silk protein sericin for regenerative medicine: an injectable, photoluminescent, cell-adhesive 3D hydrogel

    OpenAIRE

    Wang, Zheng; Zhang, Yeshun; Zhang, Jinxiang; Huang, Lei; Liu, Jia; Li, Yongkui; Zhang, Guozheng; Kundu, Subhas C.; Wang, Lin

    2014-01-01

    Sericin, a major component of silk, has a long history of being discarded as a waste during silk processing. The value of sericin for tissue engineering is underestimated and its potential application in regenerative medicine has just begun to be explored. Here we report the successful fabrication and characterization of a covalently-crosslinked 3D pure sericin hydrogel for delivery of cells and drugs. This hydrogel is injectable, permitting its implantation through minimally invasive approac...

  6. X-ray diffraction study of nanocrystalline and amorphous structure within major and minor ampullate dragline spider silks

    Energy Technology Data Exchange (ETDEWEB)

    Sampath, Sujatha; Isdebski, Thomas; Jenkins, Janelle E.; Ayon, Joel V.; Henning, Robert W.; Orgel, Joseph P.R.O.; Antipoa, Olga; Yarger, Jeffery L. (AZU)

    2012-07-25

    Synchrotron X-ray micro-diffraction experiments were carried out on Nephila clavipes (NC) and Argiope aurantia (AA) major (MA) and minor ampullate (MiA) fibers that make up dragline spider silk. The diffraction patterns show a semi-crystalline structure with {beta}-poly(L-alanine) nanocrystallites embedded in a partially oriented amorphous matrix. A superlattice reflection 'S' diffraction ring is observed, which corresponds to a crystalline component larger in size and is poorly oriented, when compared to the {beta}-poly(L-alanine) nanocrystallites that are commonly observed in dragline spider silks. Crystallite size, crystallinity and orientation about the fiber axis have been determined from the wide-angle X-ray diffraction (WAXD) patterns. In both NC and AA, the MiA silks are found to be more highly crystalline, when compared with the corresponding MA silks. Detailed analysis on the amorphous matrix shows considerable differences in the degree of order of the oriented amorphous component between the different silks studied and may play a crucial role in determining the mechanical properties of the silks.

  7. Benefits of size dimorphism and copulatory silk wrapping in the sexually cannibalistic nursery web spider, Pisaurina mira.

    Science.gov (United States)

    Anderson, Alissa G; Hebets, Eileen A

    2016-02-01

    In sexually cannibalistic animals, male fitness is influenced not only by successful mate acquisition and egg fertilization, but also by avoiding being eaten. In the cannibalistic nursery web spider, Pisaurina mira, the legs of mature males are longer in relation to their body size than those of females, and males use these legs to aid in wrapping a female's legs with silk prior to and during copulation. We hypothesized that elongated male legs and silk wrapping provide benefits to males, in part through a reduced likelihood of sexual cannibalism. To test this, we paired females of random size with males from one of two treatment groups-those capable of silk wrapping versus those incapable of silk wrapping. We found that males with relatively longer legs and larger body size were more likely to mate and were less likely to be cannibalized prior to copulation. Regardless of relative size, males capable of silk wrapping were less likely to be cannibalized during or following copulation and had more opportunities for sperm transfer (i.e. pedipalpal insertions). Our results suggest that male size and copulatory silk wrapping are sexually selected traits benefiting male reproductive success. PMID:26911340

  8. Key stress factors and parameters for production optimisation of silk-elastin-like proteins in E. coli BL21(DE3)

    OpenAIRE

    Collins, Tony; Silva, João Azevedo; Costa, André da; Branca, Fernando; Machado, Raul; Casal, Margarida

    2013-01-01

    Silk-elastin-like proteins (SELPs) combining the physicochemical and biological properties of silk and elastin have a high potential for use in the pharmaceutical, regenerative medicine and materials fields. Their development for use is however restrained by their production levels. We have recently synthesised a series of novel silk-elastin-like proteins and here we will describe the optimisation of the production of these with the pET-E. coli BL21(DE3) expression system. Both...

  9. Differential binding of the Bombyx silk gland-specific factor SGFB to its target DNA sequence drives posterior-cell-restricted expression.

    OpenAIRE

    Horard, B; Julien, E; Nony, P; Garel, A; Couble, P

    1997-01-01

    The gene encoding the silk protein P25 in Bombyx mori is expressed in the posterior silk gland (PSG) cells and repressed in the middle silk gland (MSG) cells. To identify the factors involved in this transcription-dependent spatial restriction, we examined the P25 chromatin in PSG and MSG nuclei by DNase I-aided ligation-mediated PCR and analyzed the expression of various P25-lacZ constructs in biolistically treated silk glands. P25 promoter activation depends on two cis-acting elements. One ...

  10. Ovary Apical Abortion under Water Deficit Is Caused by Changes in Sequential Development of Ovaries and in Silk Growth Rate in Maize1[OPEN

    Science.gov (United States)

    Tardieu, François

    2016-01-01

    Grain abortion allows the production of at least a few viable seeds under water deficit but causes major yield loss. It is maximum for water deficits occurring during flowering in maize (Zea mays). We have tested the hypothesis that abortion is linked to the differential development of ovary cohorts along the ear and to the timing of silk emergence. Ovary volume and silk growth were followed over 25 to 30 d under four levels of water deficit and in four hybrids in two experiments. A position-time model allowed characterizing the development of ovary cohorts and their silk emergence. Silk growth rate decreased in water deficit and stopped 2 to 3 d after first silk emergence, simultaneously for all ovary cohorts, versus 7 to 8 d in well-watered plants. Abortion rate in different treatments and positions on the ear was not associated with ovary growth rate. It was accounted for by the superposition of (1) the sequential emergence of silks originating from ovaries of different cohorts along the ear with (2) one event occurring on a single day, the simultaneous silk growth arrest. Abortion occurred in the youngest ovaries whose silks did not emerge 2 d before silk arrest. This mechanism accounted for more than 90% of drought-related abortion in our experiments. It resembles the control of abortion in a large range of species and inflorescence architectures. This finding has large consequences for breeding drought-tolerant maize and for modeling grain yields in water deficit. PMID:26598464

  11. Ovary Apical Abortion under Water Deficit Is Caused by Changes in Sequential Development of Ovaries and in Silk Growth Rate in Maize.

    Science.gov (United States)

    Oury, Vincent; Tardieu, François; Turc, Olivier

    2016-06-01

    Grain abortion allows the production of at least a few viable seeds under water deficit but causes major yield loss. It is maximum for water deficits occurring during flowering in maize (Zea mays). We have tested the hypothesis that abortion is linked to the differential development of ovary cohorts along the ear and to the timing of silk emergence. Ovary volume and silk growth were followed over 25 to 30 d under four levels of water deficit and in four hybrids in two experiments. A position-time model allowed characterizing the development of ovary cohorts and their silk emergence. Silk growth rate decreased in water deficit and stopped 2 to 3 d after first silk emergence, simultaneously for all ovary cohorts, versus 7 to 8 d in well-watered plants. Abortion rate in different treatments and positions on the ear was not associated with ovary growth rate. It was accounted for by the superposition of (1) the sequential emergence of silks originating from ovaries of different cohorts along the ear with (2) one event occurring on a single day, the simultaneous silk growth arrest. Abortion occurred in the youngest ovaries whose silks did not emerge 2 d before silk arrest. This mechanism accounted for more than 90% of drought-related abortion in our experiments. It resembles the control of abortion in a large range of species and inflorescence architectures. This finding has large consequences for breeding drought-tolerant maize and for modeling grain yields in water deficit. PMID:26598464

  12. Sign learning kink-based (SiLK) quantum Monte Carlo for molecular systems

    CERN Document Server

    Ma, Xiaoyao; Loffler, Frank; Kowalski, Karol; Bhaskaran-Nair, Kiran; Jarrell, Mark; Moreno, Juana

    2015-01-01

    The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initio ground state energies for multiple geometries of the H$_{2}$O, N$_2$, and F$_2$ molecules. The method is based on Feynman's path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of other quantum chemical methods and to exact diagonalization. Our findings demonstrate that the SiLK method is accurate and reduces or eliminates the minus sign problem.

  13. Determination of energy dissipation of a spider silk structure under impulsive loading

    Science.gov (United States)

    Alencastre, Jorge; Mago, Carlos; Rivera, Richard

    2015-09-01

    Various researches and studies have demonstrated that spider silk is much stronger and more deformable than a steel string of the same diameter from a mechanical approach. These excellent properties have caused many scientific disciplines to get involved, such as bio-mechanics, bio-materials and bio-mimetics, in order to create a material of similar properties and characteristics. It should be noted that the researches and studies have been oriented mainly as a quasi-static model. For this research, the analysis has taken a dynamic approach and determined the dissipation energy of a structure which is made of spider silk "Dragline" and produced by the Argiope-Argentata spider, through an analytical-experimental way, when being subjected to impulsive loading. Both experimental and analytical results, the latter obtained by using adjusted models, have given high levels of dissipation energy during the first cycle of vibration, which are consistent with the values suggested by other authors.

  14. Sign Learning Kink-based (SiLK) Quantum Monte Carlo for molecular systems.

    Science.gov (United States)

    Ma, Xiaoyao; Hall, Randall W; Löffler, Frank; Kowalski, Karol; Bhaskaran-Nair, Kiran; Jarrell, Mark; Moreno, Juana

    2016-01-01

    The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initio ground state energies for multiple geometries of the H2O, N2, and F2 molecules. The method is based on Feynman's path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of other quantum chemical methods and to exact diagonalization. Our findings demonstrate that the SiLK method is accurate and reduces or eliminates the minus sign problem. PMID:26747795

  15. Sign Learning Kink-based (SiLK) Quantum Monte Carlo for molecular systems

    Science.gov (United States)

    Ma, Xiaoyao; Hall, Randall W.; Löffler, Frank; Kowalski, Karol; Bhaskaran-Nair, Kiran; Jarrell, Mark; Moreno, Juana

    2016-01-01

    The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initio ground state energies for multiple geometries of the H2O, N2, and F2 molecules. The method is based on Feynman's path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of other quantum chemical methods and to exact diagonalization. Our findings demonstrate that the SiLK method is accurate and reduces or eliminates the minus sign problem.

  16. Sign learning kink-based (SiLK) quantum Monte Carlo for molecular systems

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaoyao; Hall, Randall W.; Loffler, Frank; Kowalski, Karol; Bhaskaran-Nair, Kiran; Jarrell, Mark; Moreno, Juana

    2016-01-07

    The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initio ground state energies for multiple geometries of the H2O, N2, and F2 molecules. The method is based on Feynman’s path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of other quantum chemical methods and to exact diagonalization. Our findings demonstrate that the SiLK method is accurate and reduces or eliminates the minus sign problem.

  17. Sign Learning Kink-based (SiLK) Quantum Monte Carlo for molecular systems

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaoyao [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Hall, Randall W. [Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael, California 94901 (United States); Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Löffler, Frank [Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Kowalski, Karol [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Bhaskaran-Nair, Kiran; Jarrell, Mark; Moreno, Juana [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

    2016-01-07

    The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initio ground state energies for multiple geometries of the H{sub 2}O, N{sub 2}, and F{sub 2} molecules. The method is based on Feynman’s path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of other quantum chemical methods and to exact diagonalization. Our findings demonstrate that the SiLK method is accurate and reduces or eliminates the minus sign problem.

  18. Sign Learning Kink-based (SiLK) Quantum Monte Carlo for molecular systems

    International Nuclear Information System (INIS)

    The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initio ground state energies for multiple geometries of the H2O, N2, and F2 molecules. The method is based on Feynman’s path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of other quantum chemical methods and to exact diagonalization. Our findings demonstrate that the SiLK method is accurate and reduces or eliminates the minus sign problem

  19. Central and Eastern European Countries Focus on the Silk Road Economic Belt

    Directory of Open Access Journals (Sweden)

    GEORGE CORNEL DUMITRESCU

    2015-05-01

    Full Text Available The Silk Road Economic Belt, a strategic priority of the Chinese foreign policy in 2015, draws the attention to the countries of Central and Eastern Europe through the multiple benefits that it displays (investments, economic growth, trade between the countries along its corridors, job creation, infrastructure development, the strategic importance of being part of a grandiose multi-continental project. Among these benefits an important one is represented by the opportunities of Chinese investments in infrastructure, since the EU is suffering from a credit restraint. Also, The Silk Road Economic Belt could lead to a potential increase in the bilateral trade. Analyzing the literature in the field and the various official information available online, this paper aims to depict the Chinese project form the Eastern European perspective, identifying local priorities, conflicting interests, possible infrastructure projects, routes, focusing on two strategic countries in the region: Romania and Serbia, both displaying advantages and disadvantages.

  20. The Micropillar Structure on Silk Fibroin Film Influence Intercellular Connection Mediated by Nanotubular Structures

    Directory of Open Access Journals (Sweden)

    Renchuan You

    2014-06-01

    Full Text Available Tunneling nanotubes are important membrane channels for cell-to-cell communication. In this study, we investigated the effect of the microenvironment on nanotubular structures by preparing a three-dimensional silk fibroin micropillar structure. In previous reports, tunneling nanotubes were described as stretched membrane channels between interconnected cells at their nearest distance. They hover freely in the cell culture medium and do not contact with the substratum. Interestingly, the micropillars could provide supporting points for nanotubular connection on silk fibroin films, where nanotubular structure formed a stable anchor at contact points. Consequently, the extension direction of nanotubular structure was affected by the micropillar topography. This result suggests that the hovering tunneling nanotubes in the culture medium will come into contact with the raised roadblock on the substrates during long-distance extension. These findings imply that the surface microtopography of biomaterials have an important influence on cell communication mediated by tunneling nanotubes.

  1. Modification of cotton, rayon and silk fibers by radiation induced graft co-polymerization

    International Nuclear Information System (INIS)

    Methylmethacrylate (MMA) has been grafted onto cotton, rayon and silk yarns by irradiation with 60Co gamma source in the presence of methanol used as swelling solvent at different proportions with the bulk monomer MMA. The highest grafting occurred with silk (35%) followed by rayon (22%) and the least grafting was with cotton yarn (17%). Dose rate 200 krad/h was found to yield the best results at a total dose of 500 krad. Incorporation of minute amount (1%, v/v) of an additive into MMA + MeOH system enhanced both grafting and tensile strength of the grafted yarn. It appears that the coadditive plays a better role in the grafting process for enhancing tensile strength. Water uptake and equilibrium moisture content of the grafted yarns were determined. (author)

  2. Structural characterization of the major ampullate silk spidroin-2 protein produced by the spider Nephila clavipes.

    Science.gov (United States)

    Santos-Pinto, José Roberto Aparecido Dos; Arcuri, Helen Andrade; Lubec, Gert; Palma, Mario Sergio

    2016-10-01

    Major ampullate spidroin-2 (MaSp2) is one of the most important spider silk protein, but up to now no information is available regarding the post-translational modifications (PTMs) of this protein. A gel-based mass spectrometry strategy using collision-induced dissociation (CID) and electron-transfer dissociation (ETD) fragmentation methods was used to sequence Nephila clavipes MaSp2 (including the N- and C-terminal non-repetitive domains, and the great part of the central core), and to assign a series of post-translational modifications (PTMs) on to the MaSp2 sequence. Two forms of this protein were identified, with different levels of phosphorylation along their sequences. These findings provide a basis for understanding mechanoelastic properties and can support the future design of recombinant spider silk proteins for biotechnological applications. PMID:27208434

  3. Thermal Analysis, Structural Studies and Morphology of Spider Silk-like Block Copolymers

    Science.gov (United States)

    Huang, Wenwen

    Spider silk is a remarkable natural block copolymer, which offers a unique combination of low density, excellent mechanical properties, and thermal stability over a wide range of temperature, along with biocompatibility and biodegrability. The dragline silk of Nephila clavipes, is one of the most well understood and the best characterized spider silk, in which alanine-rich hydrophobic blocks and glycine-rich hydrophilic blocks are linked together generating a functional block copolymer with potential uses in biomedical applications such as guided tissue repair and drug delivery. To provide further insight into the relationships among peptide amino acid sequence, block length, and physical properties, in this thesis, we studied synthetic proteins inspired by the genetic sequences found in spider dragline silks, and used these bioengineered spider silk block copolymers to study thermal, structural and morphological features. To obtain a fuller understanding of the thermal dynamic properties of these novel materials, we use a model to calculate the heat capacity of spider silk block copolymer in the solid or liquid state, below or above the glass transition temperature, respectively. We characterize the thermal phase transitions by temperature modulated differential scanning calorimetry (TMDSC) and thermogravimetric analysis (TGA). We also determined the crystallinity by TMDSC and compared the result with Fourier transform infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). To understand the protein-water interactions with respect to the protein amino acid sequence, we also modeled the specific reversing heat capacity of the protein-water system, Cp(T), based on the vibrational, rotational and translational motions of protein amino acid residues and water molecules. Advanced thermal analysis methods using TMDSC and TGA show two glass transitions were observed in all samples during heating. The low temperature glass transition, Tg(1), is related to

  4. One-step synthesis of natural silk sericin-based microcapsules with bionic structures.

    Science.gov (United States)

    Liu, Zhaogang; Cai, Yurong; Jia, Yaru; Liu, Lin; Kong, Xiangdong; Kundu, Subhas C; Yao, Juming

    2014-10-01

    Different techniques are being developed for fabricating microcapsules; it is still a challenge to fabricate them in an efficient and environment-friendly process. Here, a one-step green route to synthesize silk protein sericin-based microcapsules without any assistance of organic solvents is reported. By carefully changing the concentration of calcium ions accompanied with stirring, the morphology of the microcapsules can easily be regulated to form either discoidal, biconcave, cocoon-like, or tubular structures. The chelation of Ca(2+) and shearing force from agitation may induce the conformational transformation of sericin, which possibly results in the formation of microcapsules through the self-assembly of the protein subsequently. The as-prepared cocoon-like microcapsules exhibit pH-dependent stability. A potential application of microcapsules being fabricated from natural water-soluble silk protein sericin for controlled bioactive molecules loading and release system by a pH-triggered manner is quite feasible. PMID:25168858

  5. A Troubleshooting Approach towards the Generation of White Patches on Silk Fabric

    Directory of Open Access Journals (Sweden)

    Prof. S. K. Ghosh

    2015-05-01

    Full Text Available The phenomenon of occurrence of white patches on dyed silk fabric stored for few months, after production, is an intricate matter. There may be many reasons behind this occurrence. The possible sources may be deposition of fatty acid salts or growth of certain fungus or micro-organisms. This study focuses a detailed observation and analysis of white patches occurring in dyed silk fabric that has been stored for some months. An attempt has been made in this study to identify the possible reason behind the occurrence of these patches on the fabric and analyze the surface morphology of the affected areas of the fabric by adopting Scanning Electron Microscope (SEM study, Fourier Transform Infrared Spectroscopy (FT-IR and fungal growth study. The studies have identified the presence of some chemical compounds in this white deposition. Furthermore, the article also discusses the mechanism of deposition of these chemical compounds.

  6. Population, Resources and Female Labor in the Raw Silk Industry of Nagano in Meiji Japan

    Directory of Open Access Journals (Sweden)

    Tim F. Liao

    2013-03-01

    Full Text Available Gendered realities in local regions are a prominent issue in today’s global economy. However, the process of globalization in the late-19th century already involved the local Nagano women in an indispensable role in Japan’s raw silk industry. This paper studies the interplay between population growth and relatively limited resources in Nagano vis-à-vis the demand for female labor during the Meiji era, when Japan became a major raw silk producer. The local/regional constraints in Nagano interacted with economic globalization and gave Nagano its position in the global market. Therefore, we cannot ignore the consequences of local/regional constraints and advantages in global processes on female workers. Population pressure and environmental squeeze are found to have been important forces that integrated the local and regional in the global process of industrialization and trade, and together, they produced social outcomes, such as gender hierarchies in globalization and glocalization processes.

  7. Pressure and temperature dependences of the acoustic behaviors of biocompatible silk studied by using Brillouin spectroscopy

    Science.gov (United States)

    Lee, Byoung Wan; Ryeom, Junho; Ko, Jae-Hyeon; Kim, Dong Wook; Park, Chan Hum; Park, Jaehoon; Ko, Young Ho; Kim, Kwang Joo

    2016-07-01

    The elastic properties of a biocompatible silk film were investigated under temperature and pressure variations by using Brillouin spectroscopy. The Brillouin frequency shift decreased monotonically upon heating and showed a sudden change at the glass transition temperature. The existence of water molecules in the film increased the longitudinal modulus by approximately 10% and induced a relaxation peak in the hypersonic damping at ~60 ◦ C. The pressure dependences of the sound velocities of the longitudinal and the transverse acoustic modes and the refractive index were determined for the first time at pressures up to ~15.5 GPa. All these properties increased upon compression; these changes indicated that the free volume in the silk film collapsed at a pressure of about 3 GPa.

  8. Drug loading and release on tumor cells using silk fibroin–albumin nanoparticles as carriers

    International Nuclear Information System (INIS)

    Polymeric and biodegradable nanoparticles are frequently used in drug delivery systems. In this study silk fibroin–albumin blended nanoparticles were prepared using the desolvation method without any surfactant. These nanoparticles are easily internalized by the cells, reside within perinuclear spaces and act as carriers for delivery of the model drug methotrexate. Methotrexate loaded nanoparticles have better encapsulation efficiency, drug loading ability and less toxicity. The in vitro release behavior of methotrexate from the nanoparticles suggests that about 85% of the drug gets released after 12 days. The encapsulation and loading of a drug would depend on factors such as size, charge and hydrophobicity, which affect drug release. MTT assay and conjugation of particles with FITC demonstrate that the silk fibroin–albumin nanoparticles do not affect the viability and biocompatibility of cells. This blended nanoparticle, therefore, could be a promising nanocarrier for the delivery of drugs and other bioactive molecules. (paper)

  9. Strain Rate and Anisotropic Microstructure Dependent Mechanical Behaviors of Silkworm Cocoon Shells.

    Science.gov (United States)

    Xu, Jun; Zhang, Wen; Gao, Xiang; Meng, Wanlin; Guan, Juan

    2016-01-01

    Silkworm cocoons are multi-layered composite structures comprised of high strength silk fiber and sericin, and their mechanical properties have been naturally selected to protect pupas during metamorphosis from various types of external attacks. The present study attempts to gain a comprehensive understanding of the mechanical properties of cocoon shell materials from wild silkworm species Antheraea pernyi under dynamic loading rates. Five dynamic strain rates from 0.00625 s-1 to 12.5 s-1 are tested to show the strain rate sensitivity of the cocoon shell material. In the meantime, the anisotropy of the cocoon shell is considered and the cocoon shell specimens are cut along 0°, 45° and 90° orientation to the short axis of cocoons. Typical mechanical properties including Young's modulus, yield strength, ultimate strength and ultimate strain are extracted and analyzed from the stress-strain curves. Furthermore, the fracture morphologies of the cocoon shell specimens are observed under scanning electron microscopy to help understand the relationship between the mechanical properties and the microstructures of the cocoon material. A discussion on the dynamic strain rate effect on the mechanical properties of cocoon shell material is followed by fitting our experimental results to two previous models, and the effect could be well explained. We also compare natural and dried cocoon materials for the dynamic strain rate effect and interestingly the dried cocoon shells show better overall mechanical properties. This study provides a different perspective on the mechanical properties of cocoon material as a composite material, and provides some insight for bio-inspired engineering materials. PMID:26939063

  10. Strain Rate and Anisotropic Microstructure Dependent Mechanical Behaviors of Silkworm Cocoon Shells.

    Directory of Open Access Journals (Sweden)

    Jun Xu

    Full Text Available Silkworm cocoons are multi-layered composite structures comprised of high strength silk fiber and sericin, and their mechanical properties have been naturally selected to protect pupas during metamorphosis from various types of external attacks. The present study attempts to gain a comprehensive understanding of the mechanical properties of cocoon shell materials from wild silkworm species Antheraea pernyi under dynamic loading rates. Five dynamic strain rates from 0.00625 s-1 to 12.5 s-1 are tested to show the strain rate sensitivity of the cocoon shell material. In the meantime, the anisotropy of the cocoon shell is considered and the cocoon shell specimens are cut along 0°, 45° and 90° orientation to the short axis of cocoons. Typical mechanical properties including Young's modulus, yield strength, ultimate strength and ultimate strain are extracted and analyzed from the stress-strain curves. Furthermore, the fracture morphologies of the cocoon shell specimens are observed under scanning electron microscopy to help understand the relationship between the mechanical properties and the microstructures of the cocoon material. A discussion on the dynamic strain rate effect on the mechanical properties of cocoon shell material is followed by fitting our experimental results to two previous models, and the effect could be well explained. We also compare natural and dried cocoon materials for the dynamic strain rate effect and interestingly the dried cocoon shells show better overall mechanical properties. This study provides a different perspective on the mechanical properties of cocoon material as a composite material, and provides some insight for bio-inspired engineering materials.

  11. COMPARATIVE STUDY OF HEALTH STATUS BETWEEN COUNTRIES ALONG THE NEW SILK ROAD

    Directory of Open Access Journals (Sweden)

    Ju’e Yan

    2016-04-01

    Full Text Available Using World Statistics Data from the year 2012, health status differences between countries along the “New Silk Road” were compared and analyzed. Life expectancy at birth, life expectancy at age 60, healthy life expectancy, neonatal mortality rate, infant mortality rate, under-five mortality rate, maternal mortality ratio, as well as certain disease incidence rates were used. The study indicated that the 12 countries along the New Silk Road had longer life expectancy at birth. Females had longer life expectancy at birth than males, but life expectancy at age 60 was shorter than the global average, and healthy life expectancy at birth was also shorter. Maternal health status was generally good in each country. China, Russia, and 4 other countries had better children’s health status than India, Tajikistan, Pakistan, and Afghanistan. Non-communicable diseases caused higher mortality than communicable diseases and accidental injuries. However, the age standardized mortality rates of communicable diseases in India, Tajikistan, Pakistan, and Afghanistan were still relatively high. Communicable diseases were also the leading cause of reduction in life expectancy. Tuberculosis had a more significant impact on health status. In conclusion, health status varies among the New Silk Road countries. Countries including China and Iran have relatively better health status, and non communicable diseases were the predominant risk factor impacting health. However, in countries such as India and Afghanistan, mortality caused by communicable diseases is still prominent. Under the current trend of globalization, New Silk Road countries are supposed to collaborate to expand their healthcare systems, and improve the health conditions for their people.

  12. Bioconjugation of neutral protease on silk fibroin nanoparticles and application in the controllable hydrolysis of sericin.

    Science.gov (United States)

    Zhu, Lin; Hu, Ren-Ping; Wang, Hai-Yan; Wang, Yuan-Jing; Zhang, Yu-Qing

    2011-09-28

    Bombyx mori silk fibroin is a protein-based macromolecular biopolymer with remarkable biocompatibility. Silk fiber was degummed and subjected to a series of treatments, including dissolution and dialysis, to yield an aqueous solution of silk fibroin, which was introduced rapidly into excess acetone to produce crystalline silk fibroin nanoparticles (SFNs). The SFNs were conjugated covalently with a neutral protease (NP) using glutaraldehyde as the cross-linking reagent. The objective of this study was to determine the optimal conditions for biosynthesis of the SFN-NP bioconjugates. First, SFN-NP was obtained by covalent cross-linking of SFN and NP at an SFN/NP ratio of 5-8 mg:1 IU with 0.75% glutaraldehyde for 6 h at 25 °C. When adding 50 IU of the enzyme, the residual activity of biological conjugates was increased to 31.45%. Studies on the enzyme activity of SFN-NP and its kinetics showed that the stability of SFN-NP bioconjugates was greater than that of the free enzyme, the optimum reactive temperature range was increased by 5-10 °C, and the optimum pH value range was increased to 6.5-8.0. Furthermore, the thermal stability was improved to some extent. A controlled hydrolysis test using the poorly water-soluble protein sericin as a substrate and SFN-NP as the enzyme showed that the longer the reaction time (within 1 h), the smaller the molecular mass (<30 kDa) is of the sericin peptide produced. The SFN-NP bioconjugate is easily recovered by centrifugation and can be used repeatedly. The highly efficient processing technology and the use of SFN as a novel vector for a protease has great potential for research and the development of food processing. PMID:21846144

  13. Synthesis of silver nanoparticles and antibacterial property of silk fabrics treated by silver nanoparticles

    OpenAIRE

    ZHANG, GUANGYU; Liu, Yan; Gao, Xiaoliang; Chen, Yuyue

    2014-01-01

    A silver nanoparticle solution was prepared in one step by mixing AgNO3 and a multi-amino compound (RSD-NH2) solution under ambient condition. RSD-NH2 was in-house synthesized by methacrylate and polyethylene polyamine in methanol, which has abundant amino and imino groups. However, the characterization of silver nanoparticles indicated that these nanoparticles are easy to agglomerate in solution. Therefore, an in situ synthesis method of silver nanoparticles on the silk fabrics was developed...

  14. The Virtual Silk Highway -- Connectivity for Central Asia and the Caucasus

    Science.gov (United States)

    Frese, Hans

    2007-04-01

    This presentation focuses on Internet for research and education communities in the countries along the Great Silk Road, eight republics of the Former Soviet Union (Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, Turkmenistan, Azerbaijan, Armenia, Georgia) and Afghanistan. When the Internet became a standard science tool in the nineties, connectivity to this area was limited to analog telephone lines. The TAE fiber was installed from Istanbul via Tashkent to Shanghai, but it was based on international ISDN telephone calls at 10 per minute, unaffordable to communities with salaries of 300 per month. Satellites offered connectivity on short notice at better prices but funding by the communities was out of the question. Aid programs stepped in, connecting individual institutes across the area to the outside world. ISPs catered to those who could afford it, such as universities selling MBA courses, but Internet for research and education was lacking. In 2001, the NATO Science Programme added to its grants to institutes a multi-year program of providing a shared satellite service for international connectivity to all the countries above. National connectivity and solving the ``last mile problem'' was also funded, provided that a National Research and Education Network (NREN) organization was created in the country. SILK-1 ran 2002-6 for 3.5m providing 30Mbps west->east and 6Mbps east->west. QOS was implemented for video and audio conferencing. Co-funding by NRENs and others was established, but sustainability is still outstanding. Only recently, affordable fiber (<1k/month for 1 Mbps) is offered in parts of the area, so the RFP of SILK-2 in 2006 was issued in a technology-neutral way. No fiber bids were received, but a cheaper satellite service providing a total of 120/30Mbps for 3.5m in 2007-8. With fiber initiatives under way, it is hoped that part of SILK-2 can switch to fiber in 2009.

  15. Effect of Methanol Treatment on Regenerated Silk Fibroin Microparticles Prepared by the Emulsification-Diffusion Technique

    OpenAIRE

    Yodthong Baimark; Prasong Srihanam

    2009-01-01

    Silk Fibroin (SF) microparticles containing hollow structure were prepared by a water-in-oil emulsion solvent diffusion method without any surfactants. Aqueous SF solution and ethyl acetate were used as water and oil phases, respectively. Influences of SF concentration and post methanol treatment on microparticle characteristics were investigated. All microparticles contained open hollow structures. Microparticle sizes increased with the SF concentration. Conformation of SF microparticles det...

  16. NGOs and gender policy: some issues from the south Indian silk-reeling industry.

    Science.gov (United States)

    Mayoux, L

    1993-10-01

    In India, silk reeling, the middle stage in silk production, is potentially very profitable, and the silk industry has been required to adopt gender-aware policies such as appointing female staff and introducing gender sensitization training. To date, policies designed to encourage women's entrepreneurship in the reeling industry have been unsuccessful. Men have appropriated credit issued in women's names, and no women's cooperatives are currently in operation. The policies designed to encourage female entrepreneurship in reeling woefully overlooked the complexity of this work which involves a substantial investment of capital and significant risk. Women and girls continue to work as unpaid family workers and wage laborers without the benefits of governmental policies to protect their interests. In fact, attempts to introduce labor legislation to protect women have been blocked on the national level by the powerful Reelers' Association. Policies which address gender issues in the family and in the wider context of the silk industry are also lacking, and there is a wide variation in how women are able or unable to manipulate their positions to their advantage. Women's inabilities are the root cause of their inability to become entrepreneurs and improve their labor status. Nongovernmental organizations can enhance entrepreneurship and cooperative development by improving training in all aspects of running a business and in group formation. Women laborers must organize to improve wages and working conditions, and women must be able to increase their control over income and resources and their access to the outside world even as they decrease the time spent on unpaid reproductive labor. PMID:12320732

  17. Seed-specific expression of spider silk protein multimers causes long-term stability

    OpenAIRE

    Nicola eWeichert; Valeska eHauptmann; Christine eHelmold; Udo eConrad

    2016-01-01

    Seeds enable plants to germinate and to grow in situations of limited availability of nutrients. The stable storage of different seed proteins is a remarkable presumption for successful germination and growth. These strategies have been adapted and used in several molecular farming projects. In this study, we explore the benefits of seed-based expression to produce the high molecular weight spider silk protein FLAG using intein-based trans-splicing. Multimers larger than 460 kDa in size are r...

  18. Silk-Fibrin/Hyaluronic Acid Composite Gels for Nucleus Pulposus Tissue Regeneration

    OpenAIRE

    Park, Sang-Hyug; Cho, Hongsik; Gil, Eun Seok; Mandal, Biman B.; Min, Byoung-Hyun; Kaplan, David L.

    2011-01-01

    Scaffold designs are critical for in vitro culture of tissue-engineered cartilage in three-dimensional environments to enhance cellular differentiation for tissue engineering and regenerative medicine. In the present study we demonstrated silk and fibrin/hyaluronic acid (HA) composite gels as scaffolds for nucleus pulposus (NP) cartilage formation, providing both biochemical support for NP outcomes as well as fostering the retention of size of the scaffold during culture due to the combined f...

  19. Cirebon as the Silk Road: A New Approach of Heritage Tourisme and Creative Economy

    OpenAIRE

    Jaelani, Aan

    2016-01-01

    Abstract. The tourism industry and creative economy in Cirebon can not be separated from the historical aspect of the city's growth and development as silk lines in the spread of Islam, trade, and acculturation is very smooth so that the ethnic diversification becomes a major part in tourist activities. With a qualitative approach that emphasizes the phenomenon of ethnic Cirebon with tourist objects that vary in every corner of this city, then this paper confirms that Cirebon is a tourist des...

  20. Effect of freezing methods on the properties of lyophilized porous silk fibroin membranes

    OpenAIRE

    Raquel Farias Weska; Wellington Carlos Vieira Jr.; Grínia Michelle Nogueira; Marisa Masumi Beppu

    2009-01-01

    Silk fibroin is a fibrous protein that has been extensively studied for application in the biomedical field, and has been used as a scaffold for bone tissue engineering. Biomaterials made of proteins are prone to physical and chemical degradation during storage; lyophilization, a drying method that consists of freezing and drying steps, is known to promote minimal changes in structure and biological activity of biomaterials. This study evaluates the effect of freezing methods on the propertie...

  1. Protease inhibitor from insect silk - activities of derivatives expressed in vitro and in transgenic potato

    Czech Academy of Sciences Publication Activity Database

    Kodrík, Dalibor; Kludkiewicz, Barbara; Navrátil, Oldřich; Skoková Habuštová, Oxana; Horáčková, V.; Svobodová, Z.; Vinokurov, Konstantin; Sehnal, František

    2013-01-01

    Roč. 171, č. 1 (2013), s. 209-224. ISSN 0273-2289 R&D Projects: GA MZe QI91A229 Institutional support: RVO:60077344 ; RVO:61389030 Keywords : genetically modified organism * silk protease inhibitor * protease Subject RIV: ED - Physiology Impact factor: 1.687, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs12010-013-0325-9.pdf

  2. Effect of corn silk extract on acetaminophen induced renal damage in mice

    International Nuclear Information System (INIS)

    To evaluate the protective role of Corn Silk extract on Acetaminophen induced nephrotoxicity in albino mice. Study Design: Laboratory based randomized controlled trials. Place and Duration of Study: The study was carried out in experimental research laboratory University of Health Sciences and Anatomy department, Lahore. The study duration was one year from February 2012 to February 2013. Material and Methods: Twenty seven male albino mice, 6-8 weeks old weighing 30 + 5 gm, were used; these animals were randomly divided into three groups having nine mice in each group. Group A served as control and was given 16.6ml/kg normal saline intraperitoneally on first day of experiment and was sacrificed on 10th day of the experiment. Group B was treated with acetaminophen 600 mg/kg dissolved in 16.6 ml of normal saline intraperitoneally on 1st day of experiment and was sacrificed after 48 hours. Group C was given acetaminophen at a dose of 600 mg/kg intraperitoneally on first day of experiment and then corn silk extract was given by oral route at a dose of 400 mg/kg for next 8 days. The animals were sacrificed on 10th day of the experiment, the kidneys were removed; 3mm three tissue pieces were fixed in 10% formaline; processed and stained with H and E for histological study. Results: It was observed on microscopic examination that Corn silk extract reduced deleterious effects of acetaminophen on tubules of kidney as evidenced by reduction of tubular vacuolation and necrosis, absence of protein casts, vascular congestion and inflammation. Conclusion: It is concluded from current results that corn silk extract protects acetaminophen induced nephrotoxicity. (author)

  3. Effect of silk fibroin nanofibers containing silver sulfadiazine on wound healing

    OpenAIRE

    Jeong L; Kim MH; Jung JY; Min BM; Park WH

    2014-01-01

    Lim Jeong,1 Min Hee Kim,1 Ju-Young Jung,2 Byung Moo Min,3 Won Ho Park1 1Department of Advanced Organic Materials and Textile System Engineering, 2College of Veterinary Medicine, Chungnam National University, Daejeon, 3Department of Oral Biochemistry, School of Dentistry, Seoul National University, Seoul, South Korea Background: One of the promising applications of silk fibroin (SF) in biomedical engineering is its use as a scaffolding material for skin regeneration. The purpose of this study...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-03-01

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

  5. Silk fibroin nanoparticles for drug delivery purposes : stabilization, incorporation and release design

    OpenAIRE

    Ferreira, A. V.; Volkov, Vadim; Vasconcelos, Andreia; Abreu, Aana S.; Botelho, C. M.; Paulo, Artur Cavaco

    2014-01-01

    Silk Fibroin (SF) has been extensively studied for various applications due to its impressive mechanical properties and biocompatibility. Recently, SF based-particles have been proposed as controlled drug delivery systems. A new and efficient method was developed to prepare SF nanoparticles (SF-NPs) by high pressure homogenization (HPH) emulsification, in oil-in-water emulsions (o/w). During the NPs production by HPH emulsification process, the secondary SF structure changed from ran...

  6. Enzymatic degradation behavior and cytocompatibility of silk fibroin–starch–chitosan conjugate membranes

    OpenAIRE

    Baran, E. T.; Tuzlakoglu, K.; Mano, J. F.; Reis, R. L.

    2012-01-01

    The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in α-amylase was more ...

  7. Productivity Improvement in the Specialized Industrial Clusters: The Case of the Japanese Silk-Reeling Industry

    OpenAIRE

    Arimoto, Yutaka; Nakajima, Kentaro; Okazaki, Tetsuji

    2011-01-01

    We examine two sources of productivity improvement in the specialized industrial clusters. Agglomeration improves the productivity of each plant through positive externalities, shifting plant-level productivity distribution to the right. Selection expels less productive plants through competition, truncating distribution on the left. By analyzing the data of the early twentieth century Japanese silk-reeling industry, we find no evidence confirming a right shift in the distribution in clusters...

  8. Evaluation of cardioprotective effect of silk cocoon (Abresham) on isoprenaline-induced myocardial infarction in rats

    OpenAIRE

    Ritesh Kumar Srivastav; Hefazat Hussain Siddiqui; Tarique Mahmood; Farogh Ahsan

    2013-01-01

    Objective: The study was conducted to evaluate cardioprotective effect of silk cocoon (Abresham) Bombyx mori (B. mori) on isoprenaline-induced myocardial infarction. This study deals with the cocoons, which is called Abresham in the Unani system of medicine. It is one of the 64 drugs which Avicenna has mentioned in Avicenna’s tract on cardiac drugs and used in the treatment of cardiovascular diseases. Abresham is a chief ingredient of the two very famous Unani formulation viz. Khamira Abresha...

  9. The Effect of Sterilization Methods on the Physical Properties of Silk Sericin Scaffolds

    OpenAIRE

    Siritientong, Tippawan; Srichana, Teerapol; Aramwit, Pornanong

    2011-01-01

    Protein-based biomaterials respond differently to sterilization methods. Since protein is a complex structure, heat, or irradiation may result in the loss of its physical or biological properties. Recent investigations have shown that sericin, a degumming silk protein, can be successfully formed into a 3-D scaffolds after mixing with other polymers which can be applied in skin tissue engineering. The objective of this study was to investigate the effectiveness of ethanol, ethylene oxide (EtO)...

  10. The importance of cigarette packaging in a 'dark' market: the 'Silk Cut' experience.

    Science.gov (United States)

    Moodie, Crawford; Angus, Kathryn; Ford, Allison

    2014-05-01

    In a growing number of countries tobacco companies are severely restricted in how they can legally market their products. In these 'dark' markets the role of packaging as a promotional and communications tool becomes more pronounced. How packaging is used for the most expensive cigarette brands in dark markets has received limited attention however, even though these 'premium' cigarette brands significantly impact upon the profitability of tobacco companies. We outline, using retail trade press journals, how packaging was used for premium brand 'Silk Cut' in the UK from 2004 to 2011, following a comprehensive ban on tobacco advertising, promotions and sponsorship. From 2004 to 2008 packaging was used to help launch two new variants and during this period Silk Cut market share of the premium sector grew by 1.1%. Overall share of the cigarette market for the Silk Cut house (brand family) fell however due to the continuing decline of the premium sector. From 2008 to 2011 changes to the packaging were much more frequent, including the repeated use of limited-edition designs, and modifications to pack shape, texture, style of opening, cellophane, foil and inner frame. Silk Cut's share of the premium sector grew a further 2.9% from 2008 to 2011, and overall cigarette market share increased. That a premium brand can report any level of growth within such a hostile market, where most advertising, promotion and sponsorship is banned, taxation is among the highest in the world, and in the midst of a recession, is testament to the value of packaging. PMID:23152100

  11. Heterogeneous nucleation of hydroxyapatite on protein: structural effect of silk sericin

    OpenAIRE

    Takeuchi, Akari; Ohtsuki, Chikara; Miyazaki, Toshiki; Kamitakahara, Masanobu; Ogata, Shin-ichi; Yamazaki, Masao; Furutani, Yoshiaki; Kinoshita, Hisao; Tanihara, Masao

    2005-01-01

    Acidic proteins play an important role during mineral formation in biological systems, but the mechanism of mineral formation is far from understood. In this paper, we report on the relationship between the structure of a protein and hydroxyapatite deposition under biomimetic conditions. Sericin, a type of silk protein, was adopted as a suitable protein for studying structural effect on hydroxyapatite deposition, since it forms a hydroxyapatite layer on its surface in a metastable calcium pho...

  12. Structure, evolution, and expression of antimicrobial silk proteins, seroins in Lepidoptera.

    Science.gov (United States)

    Dong, Zhaoming; Song, Qianru; Zhang, Yan; Chen, Shiyi; Zhang, Xiaolu; Zhao, Ping; Xia, Qingyou

    2016-08-01

    The silks of silkworm and waxworm contain abundant antimicrobial proteins, including protease inhibitors and seroins. Protease inhibitors have antifungal activities, whereas seroins have antiviral and antibacterial activities. In order to obtain insights into the structure, evolution, and expression of seroins, we performed an extensive survey based on the available genome, transcriptome, and expressed sequence tags datasets. Sixty-four seroins were identified in 32 lepidopteran species. The phylogenetic and structural analyses revealed that seroins can be classified into five subfamilies: seroin 1, seroin 2, seroin 3, seroin 2 + 1, and seroin 3 + 3. It is interesting that seroin 2 + 1 contains two tandem seroin domains, seroin 2 and seroin 1, whereas seroin 3 + 3 has two tandem seroin 3 domains. Each seroin domain contains a proline-rich N-terminal motif and a conserved C-terminal motif. The transcriptome and EST data indicated that seroin 1 and seroin 2 genes were expressed in the silk gland but seroin 3 genes were not. Semi-quantitative RT-PCR and western blot analyses suggested that seroin 1 and seroin 2 were constantly accumulated in the silk gland of silkworm during the fifth instar, and then secreted into cocoon silk during spinning. Immunofluorescence analyses indicated that seroin 1 was secreted into the fibroin and sericin layers, whereas seroin 2 protein was only secreted into the sericin layer. However, the antimicrobial activity of seroin 2 was more effective than that of seroin 1. The presence of seroin 1 in the fibroin layer suggested that this protein not only acts as an antimicrobial protein, but might also play a role in the assembly and secretion of fibroins. Seroin 3, which was first identified here, might be related to pheromone synthesis or recognition, as it was highly expressed in male antennae and in the pheromone gland. PMID:27180727

  13. Ultrasound-Assisted Extraction of Total Flavonoids from Corn Silk and Their Antioxidant Activity

    OpenAIRE

    Ling-Li Zheng; Guan Wen; Min-Yong Yuan; Feng Gao

    2016-01-01

    Object. Ultrasound-assisted extraction of total flavonoids from corn silk and their antioxidant activities were studied. Methods. Response surface methodology was adopted to optimize the extraction conditions and antioxidant activities of the extracted total flavonoids were detected through ferric reducing antioxidant power (FRAP) assay. Results. Through a three-level, three-variable Box-Behnken design of response surface methodology (RSM) adopting yield as response, the optimal conditions we...

  14. Comparison between Silk Sutures and Cyanoacrylate Adhesive in Human Mucosa- A Clinical and Histological Study

    OpenAIRE

    Kumar, M Suresh; Natta, Sreelakshmi; Shankar, Gowri; Reddy, S Hari Krishna; Visalakshi, D; Seshiah, G V

    2013-01-01

    Background: Closing the surgical incision is an important step in the surgical procedures, the success of surgery is sometimes compromised by the defective suturing techniques or improper suturing materials, black silk sutures are more or less most often used materials in the day today surgical procedures, but these suture materials demand more time and effort from the surgeon and there is a need to substitute these materials with more user friendly and more successful wound closing materials...

  15. Chemically cross-linked silk fibroin hydrogel with enhanced elastic properties, biodegradability, and biocompatibility

    OpenAIRE

    Park, Won Ho

    2016-01-01

    Min Hee Kim, Won Ho Park Department of Advanced Organic Materials and Textile Engineering System, Chungnam National University, Daejeon, Korea Abstract: In this study, the synthesis of silk fibroin (SF) hydrogel via chemical cross-linking reactions of SF due to gamma-ray (γ-ray) irradiation was investigated, as were the resultant hydrogel’s properties. Two different hydrogels were investigated: physically cross-linked SF hydrogel and chemically cross-linked SF hydrogel i...

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

    Science.gov (United States)

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

    2008-03-01

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

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

    International Nuclear Information System (INIS)

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH2)-NGIVKAGPAIAVLGEAAL-CONH2, using the carbodiimide chemistry method. In order to avoid the dissolution of films during the modification procedure, the SFFs were first treated with 60% (v/v) ethanol aqueous solution, resulting a structural transition from unstable silk I to silk II. The investigation of modification conditions showed that the surface-modified SFFs had the satisfied antimicrobial activity and durability when they were activated by EDC.HCl/NHS solution followed by a treatment in CB peptide/PBS buffer (pH 6.5 or 8) solution at ambient temperature for 2 h. Moreover, the surface-modified SFFs showed the smaller contact angle due to the hydrophilic antimicrobial peptides coupled on the film surface, which is essential for the cell adhesion and proliferation. AFM results indicated that the surface roughness of SFFs was considerably increased after the modification by the peptides. The elemental composition analysis results also suggested that the peptides were tightly coupled to the surface of SFFs. This approach may provide a new option to engineer the surface-modified implanted materials preventing the biomaterial-centered infection (BCI)

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

    International Nuclear Information System (INIS)

    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)XDR and (CI)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

  19. 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.

  20. Antimicrobial activity of cotton and silk fabric with herbal extract by micro encapsulation

    Institute of Scientific and Technical Information of China (English)

    Saraswathi R; Krishnan PN; Dilip C

    2010-01-01

    Objective:To explore the antimicrobial activity of microcapsules encapsulated with mixture of herbs like neem, tulsi and turmeric, and its application on cellulosic fabric in the form of microcapsules.Methods: The microcapsules were prepared from the mixture of herbs by plain diffusion method, a natural encapsulation technique with yeast and applied on cotton and silk fabric by pad-dry-cure method. The microcapsules were fixed on cotton and silk fabric using the binder UF Silpure FBR-5(PA)B at 120 ℃. The antimicrobial activities of the finished fabric were assessed by using three types of bacteria includingStaphylococcus aureus,Escherichia coli andPseudomonas.Results:The results of antimicrobial activity from the tests including parallel streak method and disc diffusion method showed that activity of the mixture of herbs was very effective among the three types of bacteria selected, and the antimicrobial activity of prepared microcapsule againstPseudomonas was very good.Conclusions:The herbal microcapsule treated fabric could be applied in the field of medicine. The scanning electron microscope photographs ensure the fixing of the microcapsules firmly in the yarn structure of plain woven cotton and silk fabric.