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1

Non-bioengineered silk gland fibroin micromolded matrices to study cell-surface interactions.  

UK PubMed Central (United Kingdom)

Micropatterning/micromolding of protein molecules has played a significant role in developing biosensors, micro arrays, and tissue engineering devices for cellular investigations. Relevantly, there have been ample scopes for silk to be used as natural biomaterial in tissue engineering applications due to its attractive properties such as slow-controllable degradation, mechanical robustness, and inherent biocompatibility. In this paper, we report the fabrication of micromolded silk fibroin matrices, which have essentially been utilized to study cell-surface interactions. Fibroin protein has been isolated from the silk glands of nonmulberry Indian tropical tasar silkworms, Antheraea mylitta. The surface uniformity has been investigated using atomic force microscopy following the fabrication of silk micromolds. Subsequently, cellular interactions in terms of cell attachment, spreading, mitochondrial activity and proliferation have been studied in vitro using feline fibroblasts. Results have indicated a long term stability of patterns in micromolded silk matrices and negligible swelling. The versatility of described silk dissolution method coupled with ability to process large amount of silk protein into micromolded matrices and controllable surface topology may augment the desirability of silk fibroin as a natural biomaterial for bioengineering and biotechnological applications.

Mandal BB; Das T; Kundu SC

2009-04-01

2

Non-bioengineered silk gland fibroin micromolded matrices to study cell-surface interactions.  

Science.gov (United States)

Micropatterning/micromolding of protein molecules has played a significant role in developing biosensors, micro arrays, and tissue engineering devices for cellular investigations. Relevantly, there have been ample scopes for silk to be used as natural biomaterial in tissue engineering applications due to its attractive properties such as slow-controllable degradation, mechanical robustness, and inherent biocompatibility. In this paper, we report the fabrication of micromolded silk fibroin matrices, which have essentially been utilized to study cell-surface interactions. Fibroin protein has been isolated from the silk glands of nonmulberry Indian tropical tasar silkworms, Antheraea mylitta. The surface uniformity has been investigated using atomic force microscopy following the fabrication of silk micromolds. Subsequently, cellular interactions in terms of cell attachment, spreading, mitochondrial activity and proliferation have been studied in vitro using feline fibroblasts. Results have indicated a long term stability of patterns in micromolded silk matrices and negligible swelling. The versatility of described silk dissolution method coupled with ability to process large amount of silk protein into micromolded matrices and controllable surface topology may augment the desirability of silk fibroin as a natural biomaterial for bioengineering and biotechnological applications. PMID:19058012

Mandal, Biman B; Das, Tamal; Kundu, S C

2009-04-01

3

Non-bioengineered silk gland fibroin protein: characterization and evaluation of matrices for potential tissue engineering applications.  

Science.gov (United States)

The possibility of using wild non-mulberry silk protein as a biopolymer remains unexplored compared to domesticated mulberry silk protein. One of the main reasons for this was for not having any suitable method of extraction of silk protein fibroin from cocoons and silk glands. In this study non-bioengineered non-mulberry silk gland fibroin protein from tropical tasar silkworm Antheraea mylitta, is regenerated and characterized using 1% (w/v) sodium dodecyl sulfate (SDS). The new technique is important and unique because it uses a mild surfactant for fibroin dissolution and is advantageous over other previous reported techniques using chaotropic salts. Fabricated fibroin films are smooth as confirmed by atomic force microscopy. Circular dichroism spectrometry along with Fourier transformed infrared spectroscopy and X-ray diffraction reveal random coil/alpha-helix conformations in regenerated fibroin which transform to beta-sheets, resulting in crystalline structure and protein insolubility through ethanol treatment. Differential scanning calorimetry shows an increase in glass transition (Tg) temperature and enhanced degradation temperature on alcohol treatment. Enhanced cell attachment and viability of AH927 feline fibroblasts were observed on fibroin matrices. Higher mechanical strength along with controllable water stability of regenerated gland fibroin films make non-mulberry Indian tropical tasar silk gland fibroin protein a promising biomaterial for tissue engineering applications. PMID:18383269

Mandal, Biman B; Kundu, Subhas C

2008-08-15

4

Non-bioengineered silk gland fibroin protein: characterization and evaluation of matrices for potential tissue engineering applications.  

UK PubMed Central (United Kingdom)

The possibility of using wild non-mulberry silk protein as a biopolymer remains unexplored compared to domesticated mulberry silk protein. One of the main reasons for this was for not having any suitable method of extraction of silk protein fibroin from cocoons and silk glands. In this study non-bioengineered non-mulberry silk gland fibroin protein from tropical tasar silkworm Antheraea mylitta, is regenerated and characterized using 1% (w/v) sodium dodecyl sulfate (SDS). The new technique is important and unique because it uses a mild surfactant for fibroin dissolution and is advantageous over other previous reported techniques using chaotropic salts. Fabricated fibroin films are smooth as confirmed by atomic force microscopy. Circular dichroism spectrometry along with Fourier transformed infrared spectroscopy and X-ray diffraction reveal random coil/alpha-helix conformations in regenerated fibroin which transform to beta-sheets, resulting in crystalline structure and protein insolubility through ethanol treatment. Differential scanning calorimetry shows an increase in glass transition (Tg) temperature and enhanced degradation temperature on alcohol treatment. Enhanced cell attachment and viability of AH927 feline fibroblasts were observed on fibroin matrices. Higher mechanical strength along with controllable water stability of regenerated gland fibroin films make non-mulberry Indian tropical tasar silk gland fibroin protein a promising biomaterial for tissue engineering applications.

Mandal BB; Kundu SC

2008-08-01

5

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

Directory of Open Access Journals (Sweden)

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.

Mingying Yang; Yajun Shuai; Wen He; Sijia Min; Liangjun Zhu

2012-01-01

6

Macroporous silk fibroin cryogels.  

UK PubMed Central (United Kingdom)

Silk fibroin cryogels with remarkable properties were obtained from frozen fibroin solutions (4.2-12.6%) at subzero temperatures between -5 and -22 °C. This was achieved by the addition of ethylene glycol diglycidyl ether (EGDE) into the cryogelation system. EGDE triggers the conformational transition of fibroin from random coil to ?-sheet structure and hence fibroin gelation. One of the unique features of fibroin cryogels is their elasticity that allows them to resist complete compression without any crack development, during which water inside the cryogel is removed. The compressed cryogel immediately swells during unloading to recover its original shape. The scaffolds obtained by freeze-drying of the cryogels consist of regular, interconnected pores of diameters ranging from 50 to 10 ?m that could be regulated by the synthesis parameters. The mechanical compressive strength and the modulus of the scaffolds increase with decreasing pore diameter, that is, with decreasing gelation temperature or, with increasing fibroin or EGDE concentrations in the feed. The scaffolds produced at 12.6% fibroin exhibit a very high compressive modulus (50 MPa) making them good candidates as bone scaffold materials.

Ak F; Oztoprak Z; Karakutuk I; Okay O

2013-03-01

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A novel method for dissolution and stabilization of non-mulberry silk gland protein fibroin using anionic surfactant sodium dodecyl sulfate.  

UK PubMed Central (United Kingdom)

The importance of silk protein has increased because of its potential use as a natural biopolymer for tissue engineering and biomedical applications. In this report we show a novel and ecofriendly method for dissolution of gland silk protein fibroin. Non-mulberry silk fibroin from mature fifth instar larvae of Antheraea mylitta was found to be optimally soluble in 1% (w/v) anionic surfactant sodium dodecyl sulfate (SDS). Regenerated fibroin showed distinct bands of approximately 395 and 197 kDa on electrophoresis in non-reducing and reducing conditions, respectively. Enhanced fibroin dissolution via internalization of hydrophobic amino groups inside a hydrophilic amino acid core in the form of micelles was observed. Prolonged storage stability without gelation of SDS-extracted fibroin was seen. Atomic force microscopy showed micellar aggregation with mean micellar aggregation size of 8 nm. Circular dichroism spectroscopy revealed predominantly helical conformation due to surfactant addition with internal protein conformational changes as revealed by fluorescence spectroscopic studies.

Mandal BB; Kundu SC

2008-04-01

8

A novel method for dissolution and stabilization of non-mulberry silk gland protein fibroin using anionic surfactant sodium dodecyl sulfate.  

Science.gov (United States)

The importance of silk protein has increased because of its potential use as a natural biopolymer for tissue engineering and biomedical applications. In this report we show a novel and ecofriendly method for dissolution of gland silk protein fibroin. Non-mulberry silk fibroin from mature fifth instar larvae of Antheraea mylitta was found to be optimally soluble in 1% (w/v) anionic surfactant sodium dodecyl sulfate (SDS). Regenerated fibroin showed distinct bands of approximately 395 and 197 kDa on electrophoresis in non-reducing and reducing conditions, respectively. Enhanced fibroin dissolution via internalization of hydrophobic amino groups inside a hydrophilic amino acid core in the form of micelles was observed. Prolonged storage stability without gelation of SDS-extracted fibroin was seen. Atomic force microscopy showed micellar aggregation with mean micellar aggregation size of 8 nm. Circular dichroism spectroscopy revealed predominantly helical conformation due to surfactant addition with internal protein conformational changes as revealed by fluorescence spectroscopic studies. PMID:17969177

Mandal, Biman B; Kundu, S C

2008-04-15

9

Osteogenic and adipogenic differentiation of rat bone marrow cells on non-mulberry and mulberry silk gland fibroin 3D scaffolds.  

Science.gov (United States)

This study investigates the potential of 3D silk scaffolds fabricated using tropical tasar non-mulberry, Antheraea mylitta and mulberry, Bombyx mori silk gland fibroin proteins as substrate for osteogenic and adipogenic differentiation of rat bone marrow cells (BMCs). The scaffolds are mechanically robust and show homogenous pore distribution with high porosity and interconnected pore walls. Low immunogenicity of fabricated silk scaffolds as estimated through TNF alpha release indicates its potential as future biopolymeric graft material. Rat bone marrow cells cultured on scaffolds for 28 days under static conditions in osteogenic and adipogenic media respectively led to induction of differentiation. Proliferation and spreading of fibroblasts and bone marrow cells on silk scaffolds were observed to be dependent on scaffold porosity as revealed through confocal microscopic observations. Histological analysis shows osteogenic differentiation within silk scaffolds resulting in extensive mineralization in the form of deposited nodules as observed through intense Alizarin Red S staining. Similarly, adipogenesis was marked by the presence of lipid droplets within scaffolds on staining with Oil Red O. Real-time PCR studies reveal higher transcript levels for osteopontin (Spp1), osteocalcin (Bglap2) and osteonectin (Sparc) genes under osteogenic conditions. Similarly, upregulated adipogenic gene expression was observed within A. mylitta and B. mori scaffolds under adipogenic conditions for Peroxisome proliferator activated receptor gamma (PPARgamma2), lipoprotein lipase (LPL) and adipocyte binding protein (aP2) genes. The results suggest suitability of silk fibroin protein 3D scaffolds as natural biopolymer for potential bone and adipose tissue engineering applications. PMID:19577292

Mandal, Biman B; Kundu, Subhas C

2009-07-03

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Osteogenic and adipogenic differentiation of rat bone marrow cells on non-mulberry and mulberry silk gland fibroin 3D scaffolds.  

UK PubMed Central (United Kingdom)

This study investigates the potential of 3D silk scaffolds fabricated using tropical tasar non-mulberry, Antheraea mylitta and mulberry, Bombyx mori silk gland fibroin proteins as substrate for osteogenic and adipogenic differentiation of rat bone marrow cells (BMCs). The scaffolds are mechanically robust and show homogenous pore distribution with high porosity and interconnected pore walls. Low immunogenicity of fabricated silk scaffolds as estimated through TNF alpha release indicates its potential as future biopolymeric graft material. Rat bone marrow cells cultured on scaffolds for 28 days under static conditions in osteogenic and adipogenic media respectively led to induction of differentiation. Proliferation and spreading of fibroblasts and bone marrow cells on silk scaffolds were observed to be dependent on scaffold porosity as revealed through confocal microscopic observations. Histological analysis shows osteogenic differentiation within silk scaffolds resulting in extensive mineralization in the form of deposited nodules as observed through intense Alizarin Red S staining. Similarly, adipogenesis was marked by the presence of lipid droplets within scaffolds on staining with Oil Red O. Real-time PCR studies reveal higher transcript levels for osteopontin (Spp1), osteocalcin (Bglap2) and osteonectin (Sparc) genes under osteogenic conditions. Similarly, upregulated adipogenic gene expression was observed within A. mylitta and B. mori scaffolds under adipogenic conditions for Peroxisome proliferator activated receptor gamma (PPARgamma2), lipoprotein lipase (LPL) and adipocyte binding protein (aP2) genes. The results suggest suitability of silk fibroin protein 3D scaffolds as natural biopolymer for potential bone and adipose tissue engineering applications.

Mandal BB; Kundu SC

2009-10-01

11

Silk Fibroin Based Porous Materials  

Directory of Open Access Journals (Sweden)

Full Text Available Silk from the Bombyx mori silkworm is a protein-based fiber. Bombyx mori silk fibroin (SF) is one of the most important candidates for biomedical porous material based on its superior machinability, biocompatibility, biodegradation, bioresorbability, and so on. In this paper, we have reviewed the key features of SF. Moreover we have focused on the morphous, technical processing, and biocompatibility of SF porous materials, followed by the application research. Finally, we provide a perspective the potential and problems of SF porous materials.

Qiang Zhang; Shuqin Yan; Mingzhong Li

2009-01-01

12

Silk Gland Factor-2 (SGF-2) Involved in Fibroin Gene Transcription Consists of LIM-homeodomain, LIM-interacting, and Single-Stranded DNA-Binding Proteins.  

UK PubMed Central (United Kingdom)

SGF-2 bound to promoter elements governing posterior silk gland-specific expression of the fibroin gene in Bombyx mori. We purified SGF-2 and showed that SGF-2 contains at least four gene products; the silkworm orthologues of LIM-homeodomain protein Awh, LIM-domain binding protein (Ldb), a sequence-specific single-stranded DNA binding protein (Lcaf), and the silk protein P25/fibrohexamerin (fhx). Using co-expression of these factors in Sf9 cells, Awh, Ldb and Lcaf proteins were co-purified as a ternary complex that bound to the enhancer sequence in vitro. Lcaf interacts with Ldb as well as Awh through the conserved regions to mediate transcriptional activation in yeast. Misexpression of Awh in transgenic silkworms induces ectopic expression of the fibroin gene in the middle silk glands, where Ldb and Lcaf are expressed. Taken together, this study demonstrates that SGF-2 is a multi-subunit activator complex containing Awh. Moreover, our results suggest that the Ldb/Lcaf-protein complex serves as a scaffold to facilitate communication between transcriptional control elements.

Ohno K; Sawada JI; Takiya S; Kimoto M; Matsumoto A; Tsubota T; Uchino K; Hui CC; Sezutsu H; Handa H; Suzuki Y

2013-09-01

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sup 13 C NMR study of silk fibroin synthesis in vitro  

Energy Technology Data Exchange (ETDEWEB)

The posterior silkgland of Bombyx mori, silkworm larvae, produces abundant specific silk fibroin at about 80 {mu}g/cell for one day. In this study, the continuous production of silk fibroin in the posterior silk-gland was monitored by circumfusion cultivation using both C-13 NMR and C-13 labeling techniques in order to quantitatively determined the production of silk fibroin in vitro. The experimental setup is shown. The posterior silkglands of four larvae were collected in a 10 mm NMR sample tube under sterile condition. The C-13 NMR spectra were observed in the culture medium. The time-dependence of the C-13 NMR spectra of the culture medium containing the posterior silkglands are shown. The peak intensity for silk fibroin increased with the lapse of time. Also the peak due to the C{alpha} carbon of the serine residue of silk fibroin slightly increased, which indicates that there is a system which converts glycine to serine in the posterior silkglands. In order to discuss this silk production quantitatively, the relative intensity of the C{alpha} peaks for silk fibroin and glycine in the cultivation medium was plotted. The ability of the posterior silk-glands to produce silk protein was still high in vitro when the circumfusion cultivation technique was used. (K.I.).

Asakura, Tetsuo; Sakaguchi, Ryuji; Demura, Makoto (Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology)

1990-01-01

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?????????? Instantaneous Gelatination of Silk Fibroin Solution  

Directory of Open Access Journals (Sweden)

Full Text Available ?????????????????????????????????????????????????????????????????????????????SEM????????????????????????????????????????????????X?????????????????????????????????????????????????????????????????????????????????????????????Protein solution has a tendency of gelation. For silk fibroin solution, it needs more than ten days to gel at room temperature. This paper proposes an efficient method to promote instant silk fibroin gelatinization. SEM analysis showed that the instantaneous silk hydrogel had a porous three-dimensional network structure with random curves crossed inside. Besides, there are a lot of micro globular structures cross-boned together. The results from X-ray Dif- fraction (XRD) and Fourier Transform Infrared spectrum (FTIR) showed that the molecular structure of silk fibroin has little change and maintains random coils during the rapid gelation process. This kind of instantaneous hydrogel has ex- cellent mechanical properties and moisture retention performance, so it can be used for moisturizing cosmetics and tis- sue engineering material.

???; ??; ??; ???

2013-01-01

15

Production of silk sericin/silk fibroin blend nanofibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 nanofib...

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

16

Silk fibroin in tissue engineering.  

UK PubMed Central (United Kingdom)

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

Kasoju N; Bora U

2012-07-01

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Silk fibroin biomaterials for tissue regenerations.  

UK PubMed Central (United Kingdom)

Regeneration of tissues using cells, scaffolds and appropriate growth factors is a key approach in the treatments of tissue or organ failure. Silk protein fibroin can be effectively used as a scaffolding material in these treatments. Silk fibers are obtained from diverse sources such as spiders, silkworms, scorpions, mites and flies. Among them, silk of silkworms is a good source for the development of biomedical device. It possesses good biocompatibility, suitable mechanical properties and is produced in bulk in the textile sector. The unique combination of elasticity and strength along with mammalian cell compatibility makes silk fibroin an attractive material for tissue engineering. The present article discusses the processing of silk fibroin into different forms of biomaterials followed by their uses in regeneration of different tissues. Applications of silk for engineering of bone, vascular, neural, skin, cartilage, ligaments, tendons, cardiac, ocular, and bladder tissues are discussed. The advantages and limitations of silk systems as scaffolding materials in the context of biocompatibility, biodegradability and tissue specific requirements are also critically reviewed.

Kundu B; Rajkhowa R; Kundu SC; Wang X

2013-04-01

18

Green process to prepare silk fibroin/gelatin biomaterial scaffolds.  

UK PubMed Central (United Kingdom)

A new all-aqueous and green process is described to form three-dimensional porous silk fibroin matrices with control of structural and morphological features. Silk-based scaffolds are prepared using lyophilization. Gelatin is added to the aqueous silk fibroin solution to change the silk fibroin conformation and silk fibroin-water interactions through adjusting the hydrophilic interactions in silk fibroin-gelatin-water systems to restrain the formation of separate sheet like structures in the material, resulting in a more homogenous structure. Water annealing is used to generate insolubility in the silk fibroin-gelatin scaffold system, thereby avoiding the use of organic solvents such as methanol to lock in the beta-sheet structure. The adjusting of the concentration of gelatin, as well as the concentration of silk fibroin, leads to control of morphological and functional properties of the scaffolds. The scaffolds were homogeneous in terms of interconnected pores, with pore sizes ranging from 100 to 600 microm, depending on the concentration of silk fibroin used in the process. At the same time, the morphology of the scaffolds changed from lamellar sheets to porous structures based on the increase in gelatin content. Compared with salt-leaching aqueous-derived scaffolds and hexafluoroisopropanol (HFIP)-derived scaffolds, these freeze-dried scaffolds had a lower content of beta-sheet, resulting in more hydrophilic features. Most of gelatin was entrapped in the silk fibroin-gelatin scaffolds, without the burst release in PBS solution. During in vitro cell culture, these silk fibroin-gelatin scaffolds had improved cell-compatibility than salt-leaching silk fibroin scaffolds. This new process provides useful silk fibroin-based scaffold systems for use in tissue engineering. Furthermore, the whole process is green, including all-aqueous, room temperature and pressure, and without the use of toxic chemicals or solvents, offering new ways to load bioactive drugs or growth factors into the process.

Lu Q; Zhang X; Hu X; Kaplan DL

2010-03-01

19

Silk protein fibroin from Antheraea mylitta for cardiac tissue engineering.  

UK PubMed Central (United Kingdom)

The human heart cannot regenerate after an injury. Lost cardiomyocytes are replaced by scar tissue resulting in reduced cardiac function causing high morbidity and mortality. One possible solution to this problem is cardiac tissue engineering. Here, we have investigated the suitability of non-mulberry silk protein fibroin from Indian tropical tasar Antheraea mylitta as a scaffold for engineering a cardiac patch in vitro. We have tested cell adhesion, cellular metabolic activity, response to extracellular stimuli, cell-to-cell communication and contractility of 3-days postnatal rat cardiomyocytes on silk fibroin. Our data demonstrate that A. mylitta silk fibroin exhibits similar properties as fibronectin, a component of the natural matrix for cardiomyocytes. Comparison to mulberry Bombyx mori silk protein fibroin shows that A. mylitta silk fibroin is superior probably due to its RGD domains. 3D scaffolds can efficiently be loaded with cardiomyocytes resulting in contractile patches. In conclusion, our findings demonstrate that A. mylitta silk fibroin 3D scaffolds are suitable for the engineering of cardiac patches.

Patra C; Talukdar S; Novoyatleva T; Velagala SR; Mühlfeld C; Kundu B; Kundu SC; Engel FB

2012-03-01

20

Silk protein fibroin from Antheraea mylitta for cardiac tissue engineering.  

Science.gov (United States)

The human heart cannot regenerate after an injury. Lost cardiomyocytes are replaced by scar tissue resulting in reduced cardiac function causing high morbidity and mortality. One possible solution to this problem is cardiac tissue engineering. Here, we have investigated the suitability of non-mulberry silk protein fibroin from Indian tropical tasar Antheraea mylitta as a scaffold for engineering a cardiac patch in vitro. We have tested cell adhesion, cellular metabolic activity, response to extracellular stimuli, cell-to-cell communication and contractility of 3-days postnatal rat cardiomyocytes on silk fibroin. Our data demonstrate that A. mylitta silk fibroin exhibits similar properties as fibronectin, a component of the natural matrix for cardiomyocytes. Comparison to mulberry Bombyx mori silk protein fibroin shows that A. mylitta silk fibroin is superior probably due to its RGD domains. 3D scaffolds can efficiently be loaded with cardiomyocytes resulting in contractile patches. In conclusion, our findings demonstrate that A. mylitta silk fibroin 3D scaffolds are suitable for the engineering of cardiac patches. PMID:22240510

Patra, Chinmoy; Talukdar, Sarmistha; Novoyatleva, Tatyana; Velagala, Siva R; Mühlfeld, Christian; Kundu, Banani; Kundu, Subhas C; Engel, Felix B

2012-01-10

 
 
 
 
21

In vivo NMR analysis of incorporation of (2- sup 13 C) glycine into silk fibroin  

Energy Technology Data Exchange (ETDEWEB)

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

Asakura, Tetsuo; Nagashima, Mariko; Demura, Makoto (Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology); Osanai, Minoru

1990-01-01

22

Design and engineering of silk fibroin scaffolds with biomimetic hierarchical structures.  

UK PubMed Central (United Kingdom)

Silk scaffolds having biomimetic hierarchical porous structures were achieved by carefully tuning liquid-liquid separation in regenerated silk fibroin solutions. Such scaffolds show greatly enhanced cellular responses.

Wang H; Liu XY; Chuah YJ; Goh JC; Li JL; Xu H

2013-02-01

23

The effects of different sterilization methods on silk fibroin  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to investigate the changes in the molecular structure and physiological activities of silk fibroin induced by three different sterilization methods (steam, gamma radiation and ethylene oxide) with different dose or time period of sterilization by means of Fourier transform infrared (FT-IR) spec-troscopy, X-ray diffraction, mechanical properties and assessment of molecular weight. The results showed that the steam sterilization darkened the color of silk fibroin and obviously affected the mechanical property; gamma irradiation slightly degraded the molecular weight of silk fibroin and the speed of degradation increased with increasing irradiation dose; and ethylene oxide almost had no influence on silk fibroin expect for some slight hydrolysis on mo-lecular weight. Because ethylene oxide sterilization had the smallest influence on the quality of silk fi-broin with compared to other sterilization methods, it could be used as an efficient method to make fibroin more suitable for the development of functional foods and cosmetics.

Yahong Zhao; Xiaoli Yan; Fei Ding; Yumin Yang; Xiaosong Gu

2011-01-01

24

Protein-protein nanoimprinting of silk fibroin films.  

UK PubMed Central (United Kingdom)

Protein-protein imprinting of silk fibroin is introduced as a rapid, high-throughput method for the fabrication of nanoscale structures in silk films, through the application of heat and pressure. Imprinting on conformal surfaces is demonstrated with minor adjustments to the system, at resolutions comparable to other currently available nonplanar nanoimprint lithography techniques.

Brenckle MA; Tao H; Kim S; Paquette M; Kaplan DL; Omenetto FG

2013-05-01

25

Silk fibroin-based scaffolds for bone regeneration.  

UK PubMed Central (United Kingdom)

Porous scaffolds were prepared using regenerated Bombyx mori silk fibroin dissolved in water or hexafluoroisopropanol (HFIP). The effects of these two preparations on the formation and growth of new bone on implantation into the rabbit femoral epicondyle was examined. The aqueous-based fibroin (A-F) scaffold exhibited significantly greater osteoconductivity as judged by bone volume, bone mineral content, and bone mineral density at the implant site than the HFIP-based fibroin (HFIP-F) scaffold. Micro-CT analyses showed that the morphology of the newly formed bone differed significantly in the two types of silk fibroin scaffold. After 4 weeks of implantation, new trabecular bone was seen inside the pores of the A-F scaffold implant while the HFIP-F scaffold only contained necrotic cells. No trabecular bone was seen within the pores of the latter scaffolds, although the pores of these did contain giant cells and granulation tissue.

Kuboyama N; Kiba H; Arai K; Uchida R; Tanimoto Y; Bhawal UK; Abiko Y; Miyamoto S; Knight D; Asakura T; Nishiyama N

2013-02-01

26

Silk fibroin-based scaffolds for bone regeneration.  

Science.gov (United States)

Porous scaffolds were prepared using regenerated Bombyx mori silk fibroin dissolved in water or hexafluoroisopropanol (HFIP). The effects of these two preparations on the formation and growth of new bone on implantation into the rabbit femoral epicondyle was examined. The aqueous-based fibroin (A-F) scaffold exhibited significantly greater osteoconductivity as judged by bone volume, bone mineral content, and bone mineral density at the implant site than the HFIP-based fibroin (HFIP-F) scaffold. Micro-CT analyses showed that the morphology of the newly formed bone differed significantly in the two types of silk fibroin scaffold. After 4 weeks of implantation, new trabecular bone was seen inside the pores of the A-F scaffold implant while the HFIP-F scaffold only contained necrotic cells. No trabecular bone was seen within the pores of the latter scaffolds, although the pores of these did contain giant cells and granulation tissue. PMID:23125151

Kuboyama, Noboru; Kiba, Hideo; Arai, Kiyoshi; Uchida, Ryoichiro; Tanimoto, Yasuhiro; Bhawal, Ujjal K; Abiko, Yoshimitsu; Miyamoto, Sayaka; Knight, David; Asakura, Tetsuo; Nishiyama, Norihiro

2012-11-02

27

Production of silk sericin/silk fibroin blend nanofibers  

Directory of Open Access Journals (Sweden)

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.

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

2011-01-01

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Production of silk sericin/silk fibroin blend nanofibers  

Science.gov (United States)

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.

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

2011-08-01

29

Non-bioengineered silk fibroin protein 3D scaffolds for potential biotechnological and tissue engineering applications.  

Science.gov (United States)

This paper describes a new source for fabricating high-strength, non-bioengineered silk gland fibroin 3D scaffolds from Indian tropical tasar silkworm, Antheraea mylitta using SDS for dissolution. The scaffolds were fabricated by freeze drying at different prefreezing temperatures for pore size and porosity optimization. Superior mechanical properties with compressive strength in the range of 972 kPa were observed. The matrices were degraded by proteases within 28 d of incubation. Biocompatibility was assessed by feline fibroblast culture in vitro and confocal microscopy further confirmed adherence, spreading, and proliferation of primary dermal fibroblasts. Results indicate nonmulberry 3D silk gland fibroin protein as an inexpensive, high-strength, slow biodegradable, biocompatible, and alternative natural biomaterial. [Figure: see text]. PMID:18702171

Mandal, Biman B; Kundu, Subhas C

2008-09-01

30

Non-bioengineered silk fibroin protein 3D scaffolds for potential biotechnological and tissue engineering applications.  

UK PubMed Central (United Kingdom)

This paper describes a new source for fabricating high-strength, non-bioengineered silk gland fibroin 3D scaffolds from Indian tropical tasar silkworm, Antheraea mylitta using SDS for dissolution. The scaffolds were fabricated by freeze drying at different prefreezing temperatures for pore size and porosity optimization. Superior mechanical properties with compressive strength in the range of 972 kPa were observed. The matrices were degraded by proteases within 28 d of incubation. Biocompatibility was assessed by feline fibroblast culture in vitro and confocal microscopy further confirmed adherence, spreading, and proliferation of primary dermal fibroblasts. Results indicate nonmulberry 3D silk gland fibroin protein as an inexpensive, high-strength, slow biodegradable, biocompatible, and alternative natural biomaterial. [Figure: see text].

Mandal BB; Kundu SC

2008-09-01

31

In vitro studies on the structure and properties of silk fibroin aqueous solutions in silkworm.  

UK PubMed Central (United Kingdom)

The spinning process of silkworm in vivo attracts great attentions. In this work, the structures and properties of the silk fibroin (SF) aqueous solutions from different divisions of silk glands of silkworms were investigated by using polarized microscope, rotational rheometer, Raman spectrometer and dynamic laser light scattering instrument. It was found that only the anterior (A) division and the anterior part of middle division (MA) of silk gland showed birefringence. With flowing from the posterior part (MP) to the MA part in the middle division of silk gland, the SF aqueous solutions was gradually transformed from random coil/?-helix to ?-sheet conformation. Meantime, the elastic and viscous nature of the SF aqueous solution changed, and the mean diameter of SF aggregates increased from 118nm to 331nm. It could be concluded that the structures and properties of the SF aqueous solutions were gradually changed along the silk gland and the liquid crystal structure was initially formed in the MA part of silk gland.

Jin Y; Hang Y; Luo J; Zhang Y; Shao H; Hu X

2013-08-01

32

Microdissection of black widow spider silk-producing glands.  

Science.gov (United States)

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 case threads] and pyriform [produces attachment disc silk]. This approach is based upon anesthetizing the spider with carbon dioxide gas, subsequent separation of the cephalothorax from the abdomen, and microdissection of the abdomen to obtain the silk-producing glands. Following the separation of the different silk-producing glands, these tissues can be used to retrieve different macromolecules for distinct biochemical analyses, including quantitative real-time PCR, northern- and western blotting, mass spectrometry (MS or MS/MS) analyses to identify new silk protein sequences, search for proteins that participate in the silk assembly pathway, or use the intact tissue for cell culture or histological experiments. PMID:21248709

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

2011-01-11

33

Microdissection of black widow spider silk-producing glands.  

UK PubMed Central (United Kingdom)

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 case threads] and pyriform [produces attachment disc silk]. This approach is based upon anesthetizing the spider with carbon dioxide gas, subsequent separation of the cephalothorax from the abdomen, and microdissection of the abdomen to obtain the silk-producing glands. Following the separation of the different silk-producing glands, these tissues can be used to retrieve different macromolecules for distinct biochemical analyses, including quantitative real-time PCR, northern- and western blotting, mass spectrometry (MS or MS/MS) analyses to identify new silk protein sequences, search for proteins that participate in the silk assembly pathway, or use the intact tissue for cell culture or histological experiments.

Jeffery F; La Mattina C; Tuton-Blasingame T; Hsia Y; Gnesa E; Zhao L; Franz A; Vierra C

2011-01-01

34

Gelation of Antheraea pernyi Silk Fibroin Accelerated by Shearing  

Directory of Open Access Journals (Sweden)

Full Text Available The rapid manufacture of silk fibroin gels in mild conditions is an important subject in the field of silk-based biomaterials. In this study, the gelation of Antheraea pernyi silk fibroin (ASF) aqueous solution was induced by shearing, without chemical cross-linking agents. Simple shearing controlled and accomplished the steady and rapid conformational transition to ?-sheets with ease. The conformational transformation and rapid gelation mechanisms of ASF induced by shearing were tracked and analyzed by circular dichroism spectrometry, Fourier transform infrared spectroscopy and X-ray diffractometry, then compared with Bombyx mori silk fibroin (BSF). ASF quickly formed hydrogels within 24 - 48 h after shearing under different shearing rates for 30 - 90 min, resulting in sol-gel transformation when the ?-sheet content reached nearly 50%, which is the minimum content needed to maintain a stable hydrogel system in ASF. The gel structures remained stable once formed. The rapid gelation of ASF through shearing compared with BSF was achieved because of ASF’s alternating polyalanine-containing units, which tend to form ?-helix structures spontaneously. Further, the entropic cost during the conformational transition from the ?-helix to the ?-sheet structure is less than the cost of the transition from the random coil structure. This method is a simple, non-chemical cross-linking approach for the promotion of rapid gelation and the protection of the biological properties of ASF, and it may prove useful for application in the field of biomedical materials.

Yu Liu; Siyong Xiong; Renchuan You; Mingzhong Li

2013-01-01

35

Orientational structure formation of silk fibroin with anisotropic properties in solutions  

International Nuclear Information System (INIS)

Key words:silk fibroin, dissolution, solution's model systems, gelation, orientational crystallization, optical polarization, longitudinal stream, ? - ? transition, structure formation, phase transformations, relaxation, anisotropy of swelling and desorption, thermo- and biodegradation. Subjects of the inquiry: silk fibroin is the main subject of investigation. Fibroin's solutions were obtained on the base of water and organic solvents, containing salts. Comparative investigations were carried out by using biosolution - secretion of silkworm, solutions of silk sericin, cotton cellulose, methylcellulose, polystyrene and (co) polycrylonitrile. Aim of the inquiry: the elucidation of the regularities of silk fibroin anisotropic structures formation in the direct generation of orientational ordering in solutions taking into account of influences of its the molecular structures, configuration information, ? - ? conformational transformations, and development jointly using polarization-optical and hydrodynamic methods to control of structure formation. And also definition of possibility fields for use biopolymers anisotropic structure formation principles. Method of inquiry: birefringence, dispersion optical rotation, circular dichroism, polarization- ultramicroscope, ultracentrifuge, viscosimetry, potentiometry, differential thermal analysis, chromatography, x-ray analysis, spectroscopy. The results achieved and their novelty: the physical regularity amorphous-crystalline fibroin dissolutions in salt-containing solvents based on chains melting, distribution and redistribution were recognized; fibroin statistical parameters, molecular-mass and conformational characteristics were established; It was shown that fibroin molecules turned into fully uncoiled and oriented state with the breakdown decay of ?-spiral chain sections by I type phase transition mechanism, but in oriented state with ?-spiral conservation by II type transition; the presence of longitudinal field on the boundary 'reservoir - withdrawing capillary' of gland, initiating the transition of ?-spiral in ?-structures as well as phase separation of fibroin and sericin in stream were discovered; the phase diagram of liquidus for secret in the framework of polymers orientation crystallization conception were suggested; the mechanism of fibroin orientational crystallization under the longitudinal flow of solutions and gels was conformed experimentally; the scientific principles of oriented-crystallized fibrillar biopolymer materials receipt were established on the base of fibroin model solutions with properties of anisotropy of moisture absorption, swelling, desorption, thermo- and biodegradation; the approach of jointly using polarization-optical and hydrodynamic methods to the investigation of fibrillar biopolymers structure formation and phase transformations in solution was developed. Practical value - the elucidated physical regularities of fibroin solution allow to formulate a new idea on fibrillar biopolymer solutions formation and to get on their late model systems for practical use; the established scientific principles of orientational structure-formation and phase transformation of fibroin will be the base for development of original methods of anisotropic biopolymer materials from solutions of the polarization-optical and developed hydrodynamic methods can be used for the investigation of structure and phase transformations of wide range of fibrillar biopolymer samples. Sphere of usage: physics of anisotropic polymer systems, macromolecular compounds solutions, gels, crystals, biopolymers materials science, optical polarization and hydrodynamics. (author)

2008-01-01

36

Preparation and Characterization of Eri (Philosamia ricini) Silk Fibroin Powder  

Directory of Open Access Journals (Sweden)

Full Text Available Eri (Philosamia ricini) cocoons were dissolved with 9 M Ca(NO3)2 and then dialyzed against distilled water for 3 days. The Silk Fibroin (SF) solution was used as substrate to prepare SF powder by using freeze-drying method. The secondary structure and thermal behavior of SF powder were determined by FT-IR and TGA analyzer, respectively. The SF powder was arranged in micrometer sizes. FT-IR spectra indicated that the SF powder composed of ?-helix and ?-sheet structures and differed from silk cocoon. Thermal properties were studied by thermogravimetric technique. Difference in thermal properties between Eri silk cocoon and SF powder was found. It is a promising that conformational structure and thermal properties were influenced by changing of silk forms.

S. Yaowalak; S. Wilaiwan; S. Prasong

2009-01-01

37

Silk fibroin nanoparticles for cellular uptake and control release.  

Science.gov (United States)

Silk nanoparticles were prepared from silk fibroin solutions of domesticated Bombyx mori and tropical tasar silkworm Antheraea mylitta and investigated in respect to its particle size, surface charge, stability and morphology along with its cellular uptake and release of growth factors. The nanoparticles were stable, spherical, negatively charged, 150-170nm in average diameter and exhibited mostly Silk II (beta-sheet) structure and did not impose any overt toxicity. Cellular uptake studies showed the accumulation of fluorescence isothiocyanate conjugated silk nanoparticles in the cytosol of murine squamous cell carcinoma cells. In vitro VEGF release from the nanoparticles showed a significantly sustained release over 3 weeks, signifying the potential application as a growth factor delivery system. PMID:20060449

Kundu, Joydip; Chung, Yong-Il; Kim, Young Ha; Tae, Giyoong; Kundu, S C

2010-01-08

38

Silk fibroin nanoparticles for cellular uptake and control release.  

UK PubMed Central (United Kingdom)

Silk nanoparticles were prepared from silk fibroin solutions of domesticated Bombyx mori and tropical tasar silkworm Antheraea mylitta and investigated in respect to its particle size, surface charge, stability and morphology along with its cellular uptake and release of growth factors. The nanoparticles were stable, spherical, negatively charged, 150-170nm in average diameter and exhibited mostly Silk II (beta-sheet) structure and did not impose any overt toxicity. Cellular uptake studies showed the accumulation of fluorescence isothiocyanate conjugated silk nanoparticles in the cytosol of murine squamous cell carcinoma cells. In vitro VEGF release from the nanoparticles showed a significantly sustained release over 3 weeks, signifying the potential application as a growth factor delivery system.

Kundu J; Chung YI; Kim YH; Tae G; Kundu SC

2010-03-01

39

Water-ethanol separation by pervaporation through silk fibroin membranes  

Energy Technology Data Exchange (ETDEWEB)

Silk fibroin is a natural polypeptide mainly composed of glycine, alanine and serine, and is a most popular natural fiber. Numerous studies have been made concerning its structure and the properties. In this report, water-ethanol separation was examined by a pervaporation method using a silk-fibroin membrane insolubilized in steam-ethanol. These membranes permeated water selectively, depending on the membrane thickness and the method of insolubilization. In other words, selective permeation of water appeared from 20 micron membrane thickness. Selectivity increased with the thickness, whereas the rate of permeation decreased accordingly. Insolubilization by steaming was effective for enhancing the selectivity. Activation energy for permeation obtained from the Arrhenius plots was between 5 and 8 kcal/mole. Separation factor reduced somewhat on the high temperature side, but it was only little being correlated with the high rate of permeation. (9 figs, 9 refs)

Hirotsu, Toshihiro; Nakajima, Shigeru; Kitamura, Aio; Mizoguchi, Kensaku; Suda, Yoshio

1988-02-10

40

In vivo degradation of three-dimensional silk fibroin scaffolds.  

UK PubMed Central (United Kingdom)

Three-dimensional porous scaffolds prepared from regenerated silk fibroin using either an all-aqueous process or a process involving an organic solvent, hexafluoroisopropanol (HFIP), have shown promise in cell culture and tissue engineering applications. However, their biocompatibility and in vivo degradation have not been fully established. The present study was conducted to systematically investigate how processing method (aqueous vs. organic solvent) and processing variables (silk fibroin concentration and pore size) affect the short-term (up to 2 months) and long-term (up to 1 year) in vivo behavior of the protein scaffolds in both nude and Lewis rats. The samples were analyzed by histology for scaffold morphological changes and tissue ingrowth, and by real-time RT-PCR and immunohistochemistry for immune responses. Throughout the period of implantation, all scaffolds were well tolerated by the host animals and immune responses to the implants were mild. Most scaffolds prepared from the all-aqueous process degraded to completion between 2 and 6 months, while those prepared from organic solvent (hexafluoroisopropanol (HFIP)) process persisted beyond 1 year. Due to widespread cellular invasion throughout the scaffold, the degradation of aqueous-derived scaffolds appears to be more homogeneous than that of HFIP-derived scaffolds. In general and especially for the HFIP-derived scaffolds, a higher original silk fibroin concentration (e.g. 17%) and smaller pore size (e.g. 100-200microm) resulted in lower levels of tissue ingrowth and slower degradation. These results demonstrate that the in vivo behavior of the three-dimensional silk fibroin scaffolds is related to the morphological and structural features that resulted from different scaffold preparation processes. The insights gained in this study can serve as a guide for processing scenarios to match desired morphological and structural features and degradation time with tissue-specific applications.

Wang Y; Rudym DD; Walsh A; Abrahamsen L; Kim HJ; Kim HS; Kirker-Head C; Kaplan DL

2008-08-01

 
 
 
 
41

A pilot study of macrophage responses to silk fibroin particles.  

UK PubMed Central (United Kingdom)

Silk fibroin (SF) shows promise for tissue engineering and other biomedical applications due to its excellent biocompatibility, unique biomechanical properties, and controllable biodegradability. The particulate form of SF materials may have many potential uses, including the use as a filler for tissue defects or as a controlled-release agent for drug delivery. However, many past in vivo and in vitro studies evaluating the biocompatibility and biodegradability of SF have involved bulk implants. It is essential to evaluate the inflammatory effects of SF particles before further use. In this study, two different sizes of SF particles were evaluated to assess their impact on the release of tumor necrosis factor (TNF)-?, interleukin (IL)-1?, and IL-6, in comparison with lipopolysaccharide positive control stimulation. The inflammatory processes were characterized using real-time reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, and light microscopy evaluations. The results indicated that small silk fibroin particles and large silk fibroin particles, in culture with RAW 264.7 murine macrophage cells for 24 h, caused up-regulation of mRNA coding for TNF-?, which indicated that both size of particles have potential inflammatory effects. There was a statistically significant increase in this up-regulation under small silk fibroin stimulation. However, the immunosorbent assay suggested that there was virtually no observed release of IL-1?, IL-6, or TNF-?, relative to the control group. The results suggest that SF particles of the chosen dimensions may have good biocompatibility in culture with RAW 264.7 murine macrophages.

Cui X; Wen J; Zhao X; Chen X; Shao Z; Jiang JJ

2013-05-01

42

A novel growth process of calcium carbonate crystals in silk fibroin hydrogel system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report an interesting finding of calcium carbonate (CaCO3) crystal growth in the silk fibroin (SF) hydrogel with different concentrations by a simple ion diffusion method. The experimental results indicate that the CaCO3 crystals obtained from silk fibroin gels with low and high concentrations ar...

Ma, Yufei; Feng, Qingling; Bourrat, Xavier

43

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

Directory of Open Access Journals (Sweden)

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(NO3)2-methanol, Ca(NO3)2-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 (?-form, type II ?-turn), while the other treatments produced more silk II (?-form, anti-parallel ?-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.

Zhang Hao; Li Ling-ling; Dai Fang-yin; Zhang Hao-hao; Ni Bing; Zhou Wei; Yang Xia; Wu Yu-zhang

2012-01-01

44

Chondrogenic differentiation of rat MSCs on porous scaffolds of silk fibroin/chitosan blends.  

UK PubMed Central (United Kingdom)

Adult bone marrow derived mesenchymal stem cells are undifferentiated, multipotential cells and have the potential to differentiate into multiple lineages like bone, cartilage or fat. In this study, polyelectrolyte complex silk fibroin/chitosan blended porous scaffolds were fabricated and examined for its ability to support in vitro chondrogenesis of mesenchymal stem cells. Silk fibroin matrices provide suitable substrate for cell attachment and proliferation while chitosan are promising biomaterial for cartilage repair due to it's structurally resemblance with glycosaminoglycans. We compared the formation of cartilaginous tissue in the silk fibroin/chitosan blended scaffolds with rat mesenchymal stem cells and cultured in vitro for 3 weeks. Additionally, pure silk fibroin scaffolds of non-mulberry silkworm, Antheraea mylitta and mulberry silkworm, Bombyx mori were also utilized for comparative studies. The constructs were analyzed for cell attachment, proliferation, differentiation, histological and immunohistochemical evaluations. Silk fibroin/chitosan blended scaffolds supported the cell attachment and proliferation as indicated by SEM observation, Confocal microscopy and metabolic activities. Alcian Blue and Safranin O histochemistry and expression of collagen II indicated the maintenance of chondrogenic phenotype in the constructs after 3 weeks of culture. Glycosaminoglycans and collagen accumulated in all the scaffolds and was highest in silk fibroin/chitosan blended scaffolds and pure silk fibroin scaffolds of A. mylitta. Chondrogenic differentiation of MSCs in the silk fibroin/chitosan and pure silk fibroin scaffolds was evident by real-time PCR analysis for cartilage-specific ECM gene markers. The results represent silk fibroin/chitosan blended 3D scaffolds as suitable scaffold for mesenchymal stem cells-based cartilage repair.

Bhardwaj N; Kundu SC

2012-04-01

45

Chondrogenic differentiation of rat MSCs on porous scaffolds of silk fibroin/chitosan blends.  

Science.gov (United States)

Adult bone marrow derived mesenchymal stem cells are undifferentiated, multipotential cells and have the potential to differentiate into multiple lineages like bone, cartilage or fat. In this study, polyelectrolyte complex silk fibroin/chitosan blended porous scaffolds were fabricated and examined for its ability to support in vitro chondrogenesis of mesenchymal stem cells. Silk fibroin matrices provide suitable substrate for cell attachment and proliferation while chitosan are promising biomaterial for cartilage repair due to it's structurally resemblance with glycosaminoglycans. We compared the formation of cartilaginous tissue in the silk fibroin/chitosan blended scaffolds with rat mesenchymal stem cells and cultured in vitro for 3 weeks. Additionally, pure silk fibroin scaffolds of non-mulberry silkworm, Antheraea mylitta and mulberry silkworm, Bombyx mori were also utilized for comparative studies. The constructs were analyzed for cell attachment, proliferation, differentiation, histological and immunohistochemical evaluations. Silk fibroin/chitosan blended scaffolds supported the cell attachment and proliferation as indicated by SEM observation, Confocal microscopy and metabolic activities. Alcian Blue and Safranin O histochemistry and expression of collagen II indicated the maintenance of chondrogenic phenotype in the constructs after 3 weeks of culture. Glycosaminoglycans and collagen accumulated in all the scaffolds and was highest in silk fibroin/chitosan blended scaffolds and pure silk fibroin scaffolds of A. mylitta. Chondrogenic differentiation of MSCs in the silk fibroin/chitosan and pure silk fibroin scaffolds was evident by real-time PCR analysis for cartilage-specific ECM gene markers. The results represent silk fibroin/chitosan blended 3D scaffolds as suitable scaffold for mesenchymal stem cells-based cartilage repair. PMID:22261099

Bhardwaj, Nandana; Kundu, Subhas C

2012-01-17

46

In vitro evaluation of combined sulfated silk fibroin scaffolds for vascular cell growth.  

UK PubMed Central (United Kingdom)

A combined sulfated silk fibroin scaffold is fabricated by modifying a knitted silk scaffold with sulfated silk fibroin sponges. In vitro hemocompatibility evaluation reveals that the combined sulfated silk fibroin scaffolds reduce platelet adhesion and activation, and prolong the activated partial thromboplastin time (APTT), thrombin time (TT), and prothrombin time (PT). The response of porcine endothelial cells (ECs) and smooth muscle cells (SMCs) on the scaffolds is studied to evaluate the cytocompatibility of the scaffolds. Vascular cells are seeded on the scaffolds and cultured for 2 weeks. The scaffolds demonstrate enhanced EC adhesion, proliferation, and maintenance of cellular functions. Moreover, the scaffolds inhibit SMC proliferation and induce expression of contractile SMC marker genes.

Liu H; Ding X; Bi Y; Gong X; Li X; Zhou G; Fan Y

2013-06-01

47

Controllable transition of silk fibroin nanostructures: an insight into in vitro silk self-assembly process.  

UK PubMed Central (United Kingdom)

Silk fiber is one of the strongest and toughest biological materials with hierarchical structures, where nanofibril with size <20nm is a critical factor in determining its excellent mechanical properties. Although silk nanofibrils have been found in natural and regenerated silk solutions, there is no way to actively control nanofibril formation in aqueous solution. This study shows a simple but effective method of preparing silk nanofibrils by regulating the silk self-assembly process. Through a repeated drying-dissolving process, a silk fibroin solution composed of metastable nanoparticles was first prepared and then used to reassemble nanofibrils with different sizes and secondary conformations under various temperatures and concentrations. These nanofibrils have a similar size to that of natural fibers, providing a suitable unit to further assemble the hierarchical structure in vitro. Several important issues, such as the relationships between silk nanofibrils, secondary conformations and viscosity, are also investigated, giving a new insight into the self-assembly process. In summary, besides rebuilding silk nanofibrils in aqueous solution, this study provides an important model for furthering the understanding of silk structures, properties and forming mechanisms, making it possible to regenerate silk materials with exceptional properties in the future.

Bai S; Liu S; Zhang C; Xu W; Lu Q; Han H; Kaplan DL; Zhu H

2013-08-01

48

Silk Fibroin/Starch Blend Films: Preparation and Characterization  

Directory of Open Access Journals (Sweden)

Full Text Available This study was aimed to prepare silk fibroin (SF) of Thai silk (Bombyx mori) and cassava starch blend films by solvent evaporation method. The SF solution was firstly prepared from the cocoons by dissolving pure silk fibroin with tertiary solvent system of CaCl2: Ethanol: H2O (1:2:8 by mol). Cassava starch solution could be prepared by boiling at high temperature. The mixture of the SF and cassava starch solution was then blended and cast on the polystyrene plates. The obtained films were investigated on their morphology, secondary structures and thermal properties by using SEM, FTIR and thermogravimetry, respectively. The results found that SF blended with starch could be formed the higher ratio of ?-sheet. With cross-section images, the blend films showed homogeneously texture. In addition, the blend film gradually increased its thermal properties when the starch blended ratio was increased. In conclusion, the SF/starch blend films could be adjusted their properties by varying the blend ratio.

Prasong Srihanam

2011-01-01

49

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

UK PubMed Central (United Kingdom)

This study discusses the possibilities of liquid silk (Silk gland silk) of Muga and Eri silk, the indigenous non mulberry silkworms of North Eastern region of India, as potential biomaterials. Silk protein fibroin of Bombyx mori, commonly known as mulberry silkworm, has been extensively studied as a versatile biomaterial. As properties of different silk-based biomaterials vary significantly, it is important to characterize the non mulberry silkworms also in this aspect. Fibroin was extracted from the posterior silk gland of full grown fifth instars larvae, and 2D film was fabricated using standard methods. The films were characterized using SEM, Dynamic contact angle test, FTIR, XRD, DSC, and TGA and compared with respective silk fibers. SEM images of films reveal presence of some globules and filamentous structure. Films of both the silkworms were found to be amorphous with random coil conformation, hydrophobic in nature, and resistant to organic solvents. Non mulberry silk films had higher thermal resistance than mulberry silk. Fibers were thermally more stable than the films. This study provides insight into the new arena of research in application of liquid silk of non mulberry silkworms as biomaterials. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 292-333, 2013.

Dutta S; Talukdar B; Bharali R; Rajkhowa R; Devi D

2013-05-01

50

Tissue response and biodegradation of composite scaffolds prepared from Thai silk fibroin, gelatin and hydroxyapatite.  

Science.gov (United States)

This work aimed to investigate tissue responses and biodegradation, both in vitro and in vivo, of four types of Bombyx mori Thai silk fibroin based-scaffolds. Thai silk fibroin (SF), conjugated gelatin/Thai silk fibroin (CGSF), hydroxyapatite/Thai silk fibroin (SF4), and hydroxyapatite/conjugated gelatin/Thai silk fibroin (CGSF4) scaffolds were fabricated using salt-porogen leaching, dehydrothermal/chemical crosslinking and an alternate soaking technique for mineralization. In vitro biodegradation in collagenase showed that CGSF scaffolds had the slowest biodegradability, due to the double crosslinking by dehydrothermal and chemical treatments. The hydroxyapatite deposited from alternate soaking separated from the surface of the protein scaffolds when immersed in collagenase. From in vivo biodegradation studies, all scaffolds could still be observed after 12 weeks of implantation in subcutaneous tissue of Wistar rats and also following ISO10993-6: Biological evaluation of medical devices. At 2 and 4 weeks of implantation the four types of Thai silk fibroin based-scaffolds were classified as "non-irritant" to "slight-irritant", compared to Gelfoam(®) (control samples). These natural Thai silk fibroin-based scaffolds may provide suitable biomaterials for clinical applications. PMID:20976530

Tungtasana, Hathairat; Shuangshoti, Somruetai; Shuangshoti, Shanop; Kanokpanont, Sorada; Kaplan, David L; Bunaprasert, Tanom; Damrongsakkul, Siriporn

2010-10-07

51

Preparation, characterization and biocompatibility of electrospinning heparin-modified silk fibroin nanofibers.  

UK PubMed Central (United Kingdom)

In this study, the electrospun silk fibroin nanofibrous scaffolds were modified with heparin by grafting after plasma treatment and blending electrospinning. Morphology, microstructure, chemical composition and grafting efficiency of the heparin-modified silk fibroin nanofibrous scaffolds were characterized to evaluate the effect of modification by means of scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectrometer (XPS). The results showed that the heparin was successfully introduced to the silk fibroin nanofibrous scaffolds by both the two kinds of modification, and there was a hydrogen bonding between the silk fibroin and heparin. Moreover, the hydrophilicity, O-containing groups and negative charge density of the heparin-modified scaffolds were enhanced. In vitro coagulation time tests showed that the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) of the heparin-modified scaffolds were much higher than those of the pure silk fibroin scaffolds. L929 fibroblasts and EVCs spread and proliferated better on the heparin-modified scaffolds than on the pure silk fibroin scaffolds. Macrophages, neutrophils and lymphocytes were not observed in the heparin-modified scaffolds, which indicated that the modified scaffolds could induce minor inflammation in vivo. The results indicated that the electrospun heparin-modified silk fibroin nanofibrous scaffolds could be considered as ideal candidates for tissue engineering scaffolds.

Wang S; Zhang Y; Wang H; Dong Z

2011-03-01

52

Nanocomposite of silk fibroin nanofiber and montmorillonite: fabrication and morphology.  

Science.gov (United States)

The purpose of our research is creating a new nanocomposite material. Generally silk fibroin (SF) is regarded as a promising base material for biomedical uses. The incorporation of montmorillonite (MMT) into SF fibers would improve physical properties of the SF fibers. We investigated a new method of combining electospun SF with MMT. Specifically, electrospun silk nanofibers were treated with methanol and dipped in a MMT suspension. We could obtain a nanosheet composite of silk nanofibers and MMT. Their ultrastructures were successfully visualized by high resolution transmission electron microscopy. This compound was comprised of individual silk nanofibers surrounded by thin layers of MMT, each with a thickness of about 1.2 nm. This structure was confirmed by elemental analysis. We also performed IR, NMR and X-ray diffraction analyses in conjunction with morphological data. Conclusively we obtained a new composite of silk nanofiber and MMT, which has never been reported. Using this unique nanocomposite biological tests of its application for a scaffold for tissue engineering are under way. PMID:23500446

Kishimoto, Yuki; Ito, Fuyu; Usami, Hisanao; Togawa, Eiji; Tsukada, Masuhiro; Morikawa, Hideaki; Yamanaka, Shigeru

2013-03-13

53

Silk fibroin-based scaffolds for tissue engineering  

Science.gov (United States)

Silk fibroin (SF) from the Bombyx mori silkworm exhibits attractive potential applications as biomechanical materials, due to its unique mechanical and biological properties. This review outlines the structure and properties of SF, including of its biocompatibility and biodegradability. It highlights recent researches on the fabrication of various SF-based composites scaffolds that are promising for tissue engineering applications, and discusses synthetic methods of various SF-based composites scaffolds and valuable approaches for controlling cell behaviors to promote the tissue repair. The function of extracellular matrices and their interaction with cells are also reviewed here.

Li, Zi-Heng; Ji, Shi-Chen; Wang, Ya-Zhen; Shen, Xing-Can; Liang, Hong

2013-09-01

54

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

55

Stem cell response to multiwalled carbon nanotube-incorporated regenerated silk fibroin films.  

UK PubMed Central (United Kingdom)

Multiwalled carbon nanotubes (MWCNTs) are considered to be the ideal reinforcements for biorelated applications on account of their remarkable structural, mechanical and thermal properties. However, before MWCNTs can be incorporated into new and existing biomedical devices, their toxicity and biocompatibility need to be investigated thoroughly. In this study, regenerated silk fibroin/MWCNT nanocomposite films were prepared using a solvent system with pre-dispersed MWCNTs. Their biocompatibility was examined in vitro using human bone marrow stem cells. Scanning electron microscopy and a WST-1 assay demonstrated that the silk fibroin/MWCN film supported BMSC attachment and growth over 7 days in culture similar to the silk fibroin only film.

Cho SY; Yun YS; Kim ES; Kim MS; Jin HJ

2011-01-01

56

Small-diameter silk vascular grafts (3 mm diameter) with a double-raschel knitted silk tube coated with silk fibroin sponge.  

UK PubMed Central (United Kingdom)

Small-diameter (less than 6 mm in diameter) vascular grafts are highly desirable due to the large demand for surgical revascularization; however, there are no available artificial grafts. Vascular grafts of 1.5 mm diameter prepared by our group with silk fibroin fiber have been proved to be excellent grafts with remarkably high patency and remodeling, based on rat implantation experiment (Enomoto et al., 2010). In this study, a silk fibroin vascular graft with 3 mm diameter which can be used for the coronary arteries or lower extremity arteries is prepared with a double-raschel knitted Bombyx mori silk fiber tube coated with B. mori silk fibroin sponge. Here the silk sponge is prepared from an aqueous solution of the silk fibroin and poly(ethylene) glycol diglycidyl ether as porogen. Sufficient strength, proper elasticity, and protection from loose ends in the implantation process are obtained for the silk fibroin graft; low water permeability and relatively large compliance are also attained. These excellent physical properties make silk fibroin grafts suitable to be implanted in a canine model.

Aytemiz D; Sakiyama W; Suzuki Y; Nakaizumi N; Tanaka R; Ogawa Y; Takagi Y; Nakazawa Y; Asakura T

2013-02-01

57

The degradation behavior of silk fibroin derived from different ionic liquid solvents  

Directory of Open Access Journals (Sweden)

Full Text Available Establishing an appropriate degradation rate is critical for tissue engineering scaffolds. In this study, the degradation rate of silk fibroin three-dimensional scaffolds was regulated by changing the molecular weight (MW) of the silk fibroin. The solubility of silk fibroin depends primarily on the ionic ability of the slovent to dissolve silk fibroin, therefore, we regulated the MW of the silk fibroin using LiBr, Ca(NO3)2 and CaCl2 to dissolve the silk fibers. SDS-PAGE analysis showed that the MW of the CaCl2-derived silk fibroin was lower than the MW produced using LiBr and Ca(NO3)2. In vitro and in vivo degradation results showed that the scaffolds prepared by low-MW silk fibroin were more rapidly degraded. Furthermore, FTIR and amino acid analysis suggested that the amorphous regions were preferentially degraded by Collagenase IA, while the SDS-PAGE and amino acid analysis indicated that the scaffolds were degraded into polypeptides (mainly at 10-30 kDa) and amino acids. Because the CaCl2-derived scaffolds contained abundant low MW polypeptides, inter-intramolecular entanglement and traversing of molecular chains in the crystallites reduced, which resulted in rapid degradation. The in vivo degradation results suggested that the degradation rate of the CaCl2-derived scaffolds was better matched to dermis regeneration, indicating that the degradation rate of silk fibroin can be effectively regulated by changing the MW to achieve a suitable dermal tissue regeneration rate.

Renchuan You; Ying Zhang; Yu Liu; Guiyang Liu; Mingzhong Li

2013-01-01

58

Silk fibroin-polyurethane blends: Physical properties and effect of silk fibroin content on viscoelasticity, biocompatibility and myoblast differentiation.  

UK PubMed Central (United Kingdom)

As a way to modify both the physical and biological properties of a highly elastic and degradable polyurethane (PU), silk fibroin (SF) was blended with the PU at differing ratios. With increasing SF content, the tensile strength decreased as did the strain at break; the stiffness increased to around 35MPa for the highest silk content. C2C12 (a mouse myoblast cell line) cells were used for in vitro experiments and showed significantly improved cell responses with increasing SF content. With increasing SF content the number of non-adherent cells was reduced at both 4 and 8h compared to the sample with the lowest SF content. In addition, muscle marker genes were upregulated compared to the sample containing no SF, and in particular sarcomeric actin and ?-actin.

Park HS; Gong MS; Park JH; Moon SI; Wall IB; Kim HW; Lee JH; Knowles JC

2013-11-01

59

A novel growth process of calcium carbonate crystals in silk fibroin hydrogel system.  

UK PubMed Central (United Kingdom)

We report an interesting finding of calcium carbonate (CaCO3) crystal growth in the silk fibroin (SF) hydrogel with different concentrations by a simple ion diffusion method. The experimental results indicate that the CaCO3 crystals obtained from silk fibroin gels with low and high concentrations are all calcites with unusual morphologies. Time-dependent growth study was carried out to investigate the crystallization process. It is believed that silk fibroin hydrogel plays an important role in the process of crystallization. The possible formation mechanism of CaCO3 crystals is proposed. This study provides a better explanation of the influence of silk fibroin concentration and its structure on CaCO3 crystals growth.

Ma Y; Feng Q; Bourrat X

2013-05-01

60

Will silk fibroin nanofiber scaffolds ever hold a useful place in Translational Regenerative Medicine?  

UK PubMed Central (United Kingdom)

Presently, some view silk fibroin-based biomaterials as obsolete, being outperformed by a host of newly discovered biomaterials. But several lines of evidence support the notion that silk fibroin proteins, especially those from B. mori and spiders and their recombinant forms, particularly in the form of electrospun nanofiber scaffolds, still represent promising tools for human tissue engineering/regeneration. Inevitably, the allure of recently reported biomaterials turns away many scientists and resources from the aim of more deeply elucidating the biological interactions of the various kinds of silk fibroin nanofiber scaffolds in vivo. But, even the biological features of newly reported biomaterials are not investigated in adequate depth. Hence, collaborative efforts among biomaterialists, biomedical experts, and private firms must be undertaken on a much greater scale than hitherto done to assess the real usefulness of silk fibroin proteins, thereby allowing or denying their useful introduction into the fields of Translational Regenerative Medicine.

Ubaldo A; Ilaria DP; Anna C; Giuliano F

2011-01-01

 
 
 
 
61

Effect of Silk Fibroin Content on the Bionic Mineralization and In Vitro Cellular Compatibility of Silk Fibroin/Hydroxyapaptite Nanocomposites  

Directory of Open Access Journals (Sweden)

Full Text Available Silk fibroin and hydroxyapatite nanocomposites (SF/HA) with various SF content were prepared. Effect of Silk fibroin content on the bionic mineralization and cellular compatibility in vitro of HA nanocrystals (n-HA) was investigated. The results show that SF content has an obvious effect on the nucleation and growth of n-HA. However, though SF content does not show obvious difference on the nucleation and growth of n-HA, it has obvious effect on the n-HA aggregation. When SF content is less than 20wt%, n-HA orderly disperses in SF matrix. While the SF content is more than 20wt%, the n-HA aggregation becomes disordered. The in vitro cellular compatibility experiments demonstrate that the SF/HA composites exhibit better cell affinity than pure n-HA. However, SF content has no obvious effect on the cell affinity of n-SF/HA 20wt% SF/HA and 30wt% SF/HA show better osteoblast proliferation.

ZHU Yun-Rong, CHEN Yu-Yun, XU Guo-Hua, YE Xiao-Jian, ZHONG Jian, HE Dan-Nong

2012-01-01

62

Microrheological Studies of Regenerated Silk Fibroin Solution by Video Microscopy  

CERN Multimedia

We have carried out studies on the rheological properties of regenerated silk fibroin (RSF) solution using video microscopy. The degummed silk from the Bombyx mori silkworm was used to prepare RSF solution by dissolving it in calcium nitrate tetrahydrate-methanol solvent. Measurements were carried out by tracking the position of an embedded micron-sized polystyrene bead within the RSF solution through video imaging. The time dependent mean squared displacement (MSD) of the bead in solution and hence, the complex shear modulus of this solution was calculated from the bead's position information. 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. 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. By examining the distribution of MSD of beads at...

Raghu, A; Somashekar, R; Ananthamurthy, Sharath

2007-01-01

63

Porous 3-D scaffolds from regenerated silk fibroin.  

UK PubMed Central (United Kingdom)

Three fabrication techniques, freeze-drying, salt leaching and gas foaming, were used to form porous three-dimensional silk biomaterial matrixes. Matrixes were characterized for morphological and functional properties related to processing method and conditions. The porosity of the salt leached scaffolds varied between 84 and 98% with a compressive strength up to 175 +/- 3 KPa, and the gas foamed scaffolds had porosities of 87-97% and compressive strength up to 280 +/- 4 KPa. The freeze-dried scaffolds were prepared at different freezing temperatures (-80 and -20 degrees C) and subsequently treated with different concentrations (15 and 25%) and hydrophilicity alcohols. The porosity of these scaffolds was up to 99%, and the maximum compressive strength was 30 +/- 2 KPa. Changes in silk fibroin structure during processing to form the 3D matrixes were determined by FT-IR and XrD. The salt leached and gas foaming techniques produced scaffolds with a useful combination of high compressive strength, interconnected pores, and pore sizes greater than 100 microns in diameter. The results suggest that silk-based 3D matrixes can be formed for utility in biomaterial applications.

Nazarov R; Jin HJ; Kaplan DL

2004-05-01

64

Porous 3-D scaffolds from regenerated silk fibroin.  

Science.gov (United States)

Three fabrication techniques, freeze-drying, salt leaching and gas foaming, were used to form porous three-dimensional silk biomaterial matrixes. Matrixes were characterized for morphological and functional properties related to processing method and conditions. The porosity of the salt leached scaffolds varied between 84 and 98% with a compressive strength up to 175 +/- 3 KPa, and the gas foamed scaffolds had porosities of 87-97% and compressive strength up to 280 +/- 4 KPa. The freeze-dried scaffolds were prepared at different freezing temperatures (-80 and -20 degrees C) and subsequently treated with different concentrations (15 and 25%) and hydrophilicity alcohols. The porosity of these scaffolds was up to 99%, and the maximum compressive strength was 30 +/- 2 KPa. Changes in silk fibroin structure during processing to form the 3D matrixes were determined by FT-IR and XrD. The salt leached and gas foaming techniques produced scaffolds with a useful combination of high compressive strength, interconnected pores, and pore sizes greater than 100 microns in diameter. The results suggest that silk-based 3D matrixes can be formed for utility in biomaterial applications. PMID:15132652

Nazarov, Rina; Jin, Hyoung-Joon; Kaplan, David L

65

[Progress and prospect of electrospun silk fibroin in construction of tissue-engineering scaffold].  

UK PubMed Central (United Kingdom)

Silk fibroin is a natural macromolecular fibroin. It has broad prospects in tissue engineering application due to its good physical and mechanical properties and good biocompatibility. This paper reviews its chemistry structure, property, the usage as matrix of tissue-engineering scaffold using electrospinning technology, and the influence on growth, proliferation and function of vascular endothelial cell, smooth muscle cell, keratinocyte and fibroblast. It also addresses the advantages and disadvantages of silk fibroin applied in tissue engineering study like artificial vascular, skin, bone stent etc. The potential applications on esophageal tissue engineering and regenerative medicine were discussed.

Chen L; Zhu Y; Li Y; Liu Y; Yu J

2011-06-01

66

Silk Fibroin Film Loaded Chlorhexidine Diacetate: Interaction and Characteristics  

Directory of Open Access Journals (Sweden)

Full Text Available This study aimed to prepare Silk Fibroin (SF) films with different weight (0.5, 1 and 1.5%) for loading chlorhexidine diacetate as substrate for study their characteristics including morphology, structure and thermal properties. The morphological observation under scanning electron spectroscopy found that all of films have a smooth surface. With cross-section micrographs, the lowest SF content was smoother texture than other. The secondary structures of various films were determined by Fourier transform infrared (FTIR) spectrometer. The results showed that SF film composed of ?-sheet structures in different ratio depending on the SF content. The result suggested that high SF content formed crystalline by interaction between amino acids molecules in higher ratio than other. However, thermal properties of the SF films did not dramatically differ compared between low and high SF content. It was also found that CHX did not affect on the SF characteristics.

N. Noi; S. Yaowalak; B. Yodthong; S. Prasong

2009-01-01

67

Intermolecular interactions between natural polysaccharides and silk fibroin protein.  

UK PubMed Central (United Kingdom)

Fabricating novel functional and structural materials from natural renewable and degradable materials has attracted much attention. Natural polysaccharides and proteins are the right natural candidates due to their unique structures and properties. The polysaccharide-protein composites or blends were widely investigated, however, there are few systematical studies on the interactions between natural polysaccharides and silk fibroin protein at the molecular level. Among various interactions, hydrogen bonding, electrostatic interactions and covalent bonding play important roles in the structure and properties of the corresponding materials. Therefore, the focus is placed on the three interactions types in this review. A future challenge is to create polysaccharide and protein composites or blends with tailored structure and properties for the wide applications.

Shang S; Zhu L; Fan J

2013-04-01

68

Silk fibroin derived polypeptide-induced biomineralization of collagen.  

UK PubMed Central (United Kingdom)

Silk fibroin (SF) is extensively investigated in osteoregenerative therapy as it combines extraordinary mechanical properties and directs calcium-phosphate formation. However, the role of the peptidic fractions in inducing the protein mineralization has not been previously decoded. In this study, we investigated the mineralization of fibroin-derived polypeptides (FDPs), which were obtained through the chymotryptic separation of the hydrophobic crystalline (Cp) fractions and of the hydrophilic electronegative amorphous (Cs) fractions. When immersed in simulated body fluid (SBF), only Cs fragments demonstrated the formation of carbonated apatite, providing experimental evidence that the mineralization of SF is dictated exclusively by its electronegative amino-acidic sequences. The potential of Cs to conceptually mimic the role of anionic non-collagenous proteins in biomineralization processes was investigated via their incorporation (up to 10% by weight) in bulk osteoid-like dense collagen (DC) gels. Within 6 h in SBF, apatite was formed in DC-Cs hybrid gels, and by day 7, carbonated hydroxylapatite crystals were extensively formed. This accelerated 3-D mineralization resulted in a nine-fold increase in the compressive modulus of the hydrogel. The tailoring of the mineralization and mechanical properties of hydrogels through hybridization with FDPs could potentially have a significant impact on cell delivery and bone regenerative medicine.

Marelli B; Ghezzi CE; Alessandrino A; Barralet JE; Freddi G; Nazhat SN

2012-01-01

69

Silk fibroin derived polypeptide-induced biomineralization of collagen.  

Science.gov (United States)

Silk fibroin (SF) is extensively investigated in osteoregenerative therapy as it combines extraordinary mechanical properties and directs calcium-phosphate formation. However, the role of the peptidic fractions in inducing the protein mineralization has not been previously decoded. In this study, we investigated the mineralization of fibroin-derived polypeptides (FDPs), which were obtained through the chymotryptic separation of the hydrophobic crystalline (Cp) fractions and of the hydrophilic electronegative amorphous (Cs) fractions. When immersed in simulated body fluid (SBF), only Cs fragments demonstrated the formation of carbonated apatite, providing experimental evidence that the mineralization of SF is dictated exclusively by its electronegative amino-acidic sequences. The potential of Cs to conceptually mimic the role of anionic non-collagenous proteins in biomineralization processes was investigated via their incorporation (up to 10% by weight) in bulk osteoid-like dense collagen (DC) gels. Within 6 h in SBF, apatite was formed in DC-Cs hybrid gels, and by day 7, carbonated hydroxylapatite crystals were extensively formed. This accelerated 3-D mineralization resulted in a nine-fold increase in the compressive modulus of the hydrogel. The tailoring of the mineralization and mechanical properties of hydrogels through hybridization with FDPs could potentially have a significant impact on cell delivery and bone regenerative medicine. PMID:21982293

Marelli, Benedetto; Ghezzi, Chiara E; Alessandrino, Antonio; Barralet, Jake E; Freddi, Giuliano; Nazhat, Showan N

2011-10-06

70

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-08-15

71

Nucleation of Hydroxyapatite on Antheraea pernyi (A. pernyi) Silk Fibroin Film.  

UK PubMed Central (United Kingdom)

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

Yang M; Shuai Y; Zhou G; Mandal N; Zhu L

2013-01-01

72

Optimization of the silk scaffold sericin removal process for retention of silk fibroin protein structure and mechanical properties  

Energy Technology Data Exchange (ETDEWEB)

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.

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

73

Optimization of the silk scaffold sericin removal process for retention of silk fibroin protein structure and mechanical properties.  

UK PubMed Central (United Kingdom)

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 degrees 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 degrees C.

Teh TK; Toh SL; Goh JC

2010-05-01

74

Chemical, structural and thermal properties of Gonometa postica silk fibroin, a potential biomaterial.  

UK PubMed Central (United Kingdom)

In the present study, chemical, structural and thermal properties of fibroin from Gonometa postica, a wild silkmoth species were investigated. Silk from Gonometa rufobrunnea and Bombyx mori species were included in this study for comparison. The results indicated that G. postica and G. rufobrunnea silk exhibited similar properties whereas distinct differences were observed with B. mori silk. Amino acid analysis showed that glycine, alanine and serine accounted for more than 70% of the total amino acid content in all species. The amount of polar amino acids in Gonometa fibroin was significantly higher than for B. mori fibroin suggesting increased chemical reactivity of the former. The abundance of basic amino acids in Gonometa fibroin makes it a promising biomaterial in cell and tissue culture. Structural analysis revealed a unique ?-sheet structure of Gonometa fibroin which is comprised of both poly-alanine and poly-glycine-alanine sequences. The maximum decomposition temperatures for Gonometa and B. mori fibroin were 350°C and 320°C respectively. The influence of amino acid composition on structural and thermal properties of the silks is also discussed.

Mhuka V; Dube S; Nindi MM

2013-01-01

75

Enhancing the interface in silk-polypyrrole composites through chemical modification of silk fibroin.  

UK PubMed Central (United Kingdom)

To produce conductive, biocompatible, and mechanically robust materials for use in bioelectrical applications, we have developed a new strategy to selectively incorporate poly(pyrrole) (Ppy) into constructs made from silk fibroin. Here, we demonstrate that covalent attachment of negatively charged, hydrophilic sulfonic acid groups to the silk protein can selectively promote pyrrole absorption and polymerization within the modified films to form a conductive, interpenetrating network of Ppy and silk that is incapable of delamination. To further increase the conductivity and long-term stability of the Ppy network, a variety of small molecule sulfonic acid dopants were utilized and the properties of these silk-conducting polymer composites were monitored over time. The composites were evaluated using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), optical microscopy, energy-dispersive X-ray (EDX) spectroscopy, cyclic voltammetry, a 4-point resistivity probe and mechanical testing. In addition, the performance was evaluated following exposure to several biologically relevant enzymes. Using this strategy, we were able to produce mechanically robust polymer electrodes with stable electrochemical performance and sheet resistivities on the order of 1 × 10(2) ?/sq (conductivity ?1 S/cm).

Romero IS; Schurr ML; Lally JV; Kotlik MZ; Murphy AR

2013-02-01

76

Enhancing the interface in silk-polypyrrole composites through chemical modification of silk fibroin.  

Science.gov (United States)

To produce conductive, biocompatible, and mechanically robust materials for use in bioelectrical applications, we have developed a new strategy to selectively incorporate poly(pyrrole) (Ppy) into constructs made from silk fibroin. Here, we demonstrate that covalent attachment of negatively charged, hydrophilic sulfonic acid groups to the silk protein can selectively promote pyrrole absorption and polymerization within the modified films to form a conductive, interpenetrating network of Ppy and silk that is incapable of delamination. To further increase the conductivity and long-term stability of the Ppy network, a variety of small molecule sulfonic acid dopants were utilized and the properties of these silk-conducting polymer composites were monitored over time. The composites were evaluated using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), optical microscopy, energy-dispersive X-ray (EDX) spectroscopy, cyclic voltammetry, a 4-point resistivity probe and mechanical testing. In addition, the performance was evaluated following exposure to several biologically relevant enzymes. Using this strategy, we were able to produce mechanically robust polymer electrodes with stable electrochemical performance and sheet resistivities on the order of 1 × 10(2) ?/sq (conductivity ?1 S/cm). PMID:23320759

Romero, Isabella S; Schurr, Morgan L; Lally, Jack V; Kotlik, Mitchell Z; Murphy, Amanda R

2013-01-15

77

Silk Fibroin as an Organic Polymer for Controlled Drug Delivery  

Energy Technology Data Exchange (ETDEWEB)

The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins, were physically entrapped into the drug delivery device during processing into films. Drug release kinetics were evaluated as a function of dextran molecular weight, and film crystallinity. Treatment with methanol resulted in an increase in {beta}-sheet structure, an increase in crystallinity and an increase in film surface hydrophobicity determined by FTIR, X-ray and contact angle techniques, respectively. The increase in crystallinity resulted in the sustained release of dextrans of molecular weights ranging from 4 to 40 kDa, whereas for less crystalline films sustained release was confined to the 40 kDa dextran. Protein release from the films was studied with horseradish peroxidase (HRP) and lysozyme (Lys) as model compounds. Enzyme release from the less crystalline films resulted in a biphasic release pattern, characterized by an initial release within the first 36 h, followed by a lag phase and continuous release between days 3 and 11. No initial burst was observed for films with higher crystallinity and subsequent release patterns followed linear kinetics for HRP, or no substantial release for Lys. In conclusion, SF is an interesting polymer for drug delivery of polysaccharides and bioactive proteins due to the controllable level of crystallinity and the ability to process the biomaterial in biocompatible fashion under ambient conditions to avoid damage to labile compounds to be delivered.

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

2006-01-01

78

Electrospinning of carboxyethyl chitosan/poly(vinyl alcohol)/silk fibroin nanoparticles for wound dressings.  

UK PubMed Central (United Kingdom)

Composite nanofibrous membranes of water-soluble N-carboxyethyl chitosan/poly(vinyl alcohol)/silk fibroin nanoparticles were successfully fabricated by electrospinning. The composite nanofibers were subjected to detailed analysis by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). SEM results investigated that the morphology and diameter of the nanofibers were affected by silk fibroin nanoparticles content. XRD and DSC demonstrated that there was intermolecular hydrogen bonding among the molecules of carboxyethyl chitosan, silk fibroin and PVA. The crystalline microstructure of the electrospun fibers was not well developed. The indirect cytotoxicity assessments of the nanofibers were studied. The result showed the nanofibers had good biocompatibility. This novel electrospun matrix would be used as potential wound dressing for skin regeneration.

Zhou Y; Yang H; Liu X; Mao J; Gu S; Xu W

2013-02-01

79

Effect of freezing methods on the properties of lyophilized porous silk fibroin membranes  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 met (more) hods on the properties of lyophilized porous silk fibroin membranes. The membranes were obtained from silk fibroin solution, frozen in liquid nitrogen or ultrafreezer, lyophilized, and then characterized by XRD, FTIR, TGA, DSC and SEM. Although the membranes presented similar physical, chemical and microstructural characteristics, quench freezing with liquid nitrogen, followed by lyophilization, promoted collapse of the membranes, while slow cooling performed by ultrafreezer preserved membrane integrity.

Weska, Raquel Farias; Vieira Jr., Wellington Carlos; Nogueira, Grínia Michelle; Beppu, Marisa Masumi

2009-06-01

80

Effect of microtopographic structures of silk fibroin on endothelial cell behavior.  

UK PubMed Central (United Kingdom)

Stent implantation has become the preferred revascularization treatment for occlusive blood vessel disease; however, there are occasionally complications resulting in re-narrowing of the treated artery. One approach to overcoming this problem is to establish a confluent monolayer of endothelial cells (ECs) on the stent, and a coating would facilitate the attachment of ECs. Silk fibroin was reported to be used as an ideal coating applied to stent for the culture of human ECs. The aim of the present study is to gain more insight into the influence of the internal microtopographical structure of silk fibroin on cell behavior, such as attachment and growth, and to further investigate its molecular mechanism using human umbilical vein ECs (HUVECs). Our results evaluated the effect of different microtopographical structures on cell behavior. In addition, we analyzed the cell cycle and investigated relevant molecules involved. The results indicated that the microtopographic structure of silk fibroin was associated with EC morphology, attachment and proliferation.

Tan JY; Wen JC; Shi WH; He Q; Zhu L; Liang K; Shao ZZ; Yu B

2013-01-01

 
 
 
 
81

Effect of freezing methods on the properties of lyophilized porous silk fibroin membranes  

Directory of Open Access Journals (Sweden)

Full Text Available 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 properties of lyophilized porous silk fibroin membranes. The membranes were obtained from silk fibroin solution, frozen in liquid nitrogen or ultrafreezer, lyophilized, and then characterized by XRD, FTIR, TGA, DSC and SEM. Although the membranes presented similar physical, chemical and microstructural characteristics, quench freezing with liquid nitrogen, followed by lyophilization, promoted collapse of the membranes, while slow cooling performed by ultrafreezer preserved membrane integrity.

Raquel Farias Weska; Wellington Carlos Vieira Jr.; Grínia Michelle Nogueira; Marisa Masumi Beppu

2009-01-01

82

Engineered silk fibroin protein 3D matrices for in vitro tumor model.  

Science.gov (United States)

3D in vitro model systems that are able to mimic the in vivo microenvironment are now highly sought after in cancer research. Antheraea mylitta silk fibroin protein matrices were investigated as potential biomaterial for in vitro tumor modeling. We compared the characteristics of MDA-MB-231 cells on A. mylitta, Bombyx mori silk matrices, Matrigel, and tissue culture plates. The attachment and morphology of the MDA-MB-231 cell line on A. mylitta silk matrices was found to be better than on B. mori matrices and comparable to Matrigel and tissue culture plates. The cells grown in all 3D cultures showed more MMP-9 activity, indicating a more invasive potential. In comparison to B. mori fibroin, A. mylitta fibroin not only provided better cell adhesion, but also improved cell viability and proliferation. Yield coefficient of glucose consumed to lactate produced by cells on 3D A. mylitta fibroin was found to be similar to that of cancer cells in vivo. LNCaP prostate cancer cells were also cultured on 3D A. mylitta fibroin and they grew as clumps in long term culture. The results indicate that A. mylitta fibroin scaffold can provide an easily manipulated microenvironment system to investigate individual factors such as growth factors and signaling peptides, as well as evaluation of anticancer drugs. PMID:21167597

Talukdar, Sarmistha; Mandal, Mahitosh; Hutmacher, Dietmar W; Russell, Pamela J; Soekmadji, Carolina; Kundu, Subhas C

2010-12-16

83

Engineered silk fibroin protein 3D matrices for in vitro tumor model.  

UK PubMed Central (United Kingdom)

3D in vitro model systems that are able to mimic the in vivo microenvironment are now highly sought after in cancer research. Antheraea mylitta silk fibroin protein matrices were investigated as potential biomaterial for in vitro tumor modeling. We compared the characteristics of MDA-MB-231 cells on A. mylitta, Bombyx mori silk matrices, Matrigel, and tissue culture plates. The attachment and morphology of the MDA-MB-231 cell line on A. mylitta silk matrices was found to be better than on B. mori matrices and comparable to Matrigel and tissue culture plates. The cells grown in all 3D cultures showed more MMP-9 activity, indicating a more invasive potential. In comparison to B. mori fibroin, A. mylitta fibroin not only provided better cell adhesion, but also improved cell viability and proliferation. Yield coefficient of glucose consumed to lactate produced by cells on 3D A. mylitta fibroin was found to be similar to that of cancer cells in vivo. LNCaP prostate cancer cells were also cultured on 3D A. mylitta fibroin and they grew as clumps in long term culture. The results indicate that A. mylitta fibroin scaffold can provide an easily manipulated microenvironment system to investigate individual factors such as growth factors and signaling peptides, as well as evaluation of anticancer drugs.

Talukdar S; Mandal M; Hutmacher DW; Russell PJ; Soekmadji C; Kundu SC

2011-03-01

84

Fabrication of a corneal-limbal tissue substitute using silk fibroin.  

UK PubMed Central (United Kingdom)

Fibroin extracted from silkworm cocoon silk provides an intriguing and potentially important biomaterial for corneal reconstruction. In this chapter we outline our methods for producing a composite of two fibroin-based materials that support the cocultivation of human limbal epithelial (HLE) cells and human limbal stromal (HLS) cells. The resulting tissue substitute consists of a stratified epithelium overlying a three-dimensional arrangement of extracellular matrix components (principally "degummed" fibroin fibers) and mesenchymal stromal cells. This tissue substitute is currently being evaluated as a tool for reconstructing the corneal limbus and corneal epithelium.

Bray LJ; George KA; Suzuki S; Chirila TV; Harkin DG

2013-01-01

85

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 ?-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.

2012-01-01

86

The Cytocompatibility of Genipin-Crosslinked Silk Fibroin Films  

Directory of Open Access Journals (Sweden)

Full Text Available There is an increasing demand for crosslinking methods of silk fibroin (SF) scaffolds in biomedical applications that could maintain the biocompatibility, bioactivity as well as improve the water resistance and mechanical properties of SF materials. In this study, SF was crosslinked effectively with genipin which is a naturally occurring iridoid glucoside and the crosslinking mechanism was investigated through FTIR and amino acid analysis. The results showed that genipin could react with the -NH2 groups on the side chains of SF macromolecules and to form inter- and intra-molecular covalent bonds, and improved the stability of SF materials significantly. In vitro, the performances of genipin-crosslinked SF films were assessed by seeding L929 cells and compared with ethanol-processed SF films, glutaraldehyde and polyethylene glycol diglycidyl ether crosslinked ones. The genipin-crosslinked SF films showed a similar affinity to cells as ethanol-processed ones, and a higher bioactivity in promoting cell growth and proliferation, inhibition of cell apoptosis, and maintenance of normal cell cycle compared with glutaraldehyde and polyethylene glycol diglycidyl ether crosslinked SF films. These features, combined with the decrease of brittleness of SF films crosslinked with chemical methods, substantiated genipin as an effective and biocompatible agent for the manufacturing of bioactive SF materials which used as tissue engineering scaffolds and drug delivery carriers.

Lingshuang Wang; Yiyu Wang; Jing Qu; Yongpei Hu; Renchuan You; Mingzhong Li

2013-01-01

87

Electrospun regenerated silk fibroin mats with enhanced mechanical properties.  

UK PubMed Central (United Kingdom)

In this paper, a simple and effective method was applied to enhance regenerated silk fibroin (RSF) mats electrospun from aqueous solution. The mats were first mechanically drawn in 90 vol.% ethanol aqueous solution and then immersed in the same solution for 30 min. The morphology, structure, thermal and mechanical properties of the RSF mats with different draw rates and draw ratios were investigated by scanning electron microscope (SEM), Raman spectroscopy, wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and tensile test. Results revealed that the content of ?-sheet conformation, the crystallinity and the number of fibers aligned to the drawing direction increased evidently with the draw ratio. The breaking strength and breaking energy of the post-treated mats at 1.4× draw ratio and 0.1mm/s draw rate were 8.6 MPa and 172.2 J/kg, respectively. However, those of the as-spun mats were only 1.8 MPa and 93.2 J/kg, respectively. The enhanced RSF mats prepared from entirely aqueous solutions may have extensive applications for tissue engineering.

Fan S; Zhang Y; Shao H; Hu X

2013-05-01

88

Preparation of Silk Fibroin Microspheres and Its Cytocompatibility  

Directory of Open Access Journals (Sweden)

Full Text Available The goal of this proof-of-concept study was the fabrication of porous silk fibroin (SF) microspheres which could be used as cell culture carriers under very mild processing conditions. The SF solution was differentiated into droplets which were induced by a syringe needle in the high-voltage electrostatic field. They were collected and frozen in liquid nitrogen and water in droplets formed ice crystals which sublimated during lyophilization and a great quantity of micropores shaped in SF microspheres. Finally, the microspheres were treated in ethanol so as to transfer the molecular conformation into ?-sheet and then they were insoluble in water. SF particles were spherical in shape with diameters in the range of 208.4 ?m to 727.3 ?m, while the pore size on the surface altered from 0.3 ?m to 10.7 ?m. In vitro, the performances of SF microspheres were assessed by culturing L-929 fibroblasts cells. Cells were observed to be tightly adhered and fully extended; also a large number of connections were established between cells. After 5-day culture, it could be observed under a confocal laser scanning microscope that the porous microenvironment offered by SF particles accelerated proliferation of cells significantly. Furthermore, porous SF particles with smaller diameters (200 - 300 ?m) might promote cell growth better. These new porous SF microspheres hold a great potential for cell culture carriers and issue engineering scaffolds.

Jing Qu; Lu Wang; Yongpei Hu; Lingshuang Wang; Renchuan You; Mingzhong Li

2013-01-01

89

Fabrication of silk fibroin nanoparticles for controlled drug delivery  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-03-15

90

Preparation and Characterization of Nanocomposite and Nanoporous Silk Fibroin Films  

Directory of Open Access Journals (Sweden)

Full Text Available Nanocomposite and nanoporous silk fibroin (SF) films were prepared by film casting of SF solution containing surfactant-free colloidal nanoparticles of methoxy poly (ethylene glycol)-b-poly (D, L-lactide) diblock copolymer (MPEG-b-PDLL). Self-condensation and nanophase separation of the nanoparticles from SF film matrix during film drying process gave nanopore structures. The colloidal nanoparticles were prepared in SF solution by modified-spontaneous emulsification solvent diffusion method without any surfactant. The interaction between SF and MPEG-b-PDLL in nanocomposite films was studied by Fourier transform infrared spectroscopy and thermogravimetry. The film transparency of SF nanocomposite films decreased as increasing the MPEG-b-PDLL ratio. Scanning Electron Microscopy (SEM) results indicated that the nanoparticle sizes in the films were in the range of 50-200 nm with spherical shape. Nanopore structures with pore size of less than 150 nm can be observed from SEM images of the film surface and cross-section. The nanopores are interconnected throughout the nanocomposite films. The number and size of nanoparticles and nanopores increased when the MPEG-b-PDLL ratio was increased.

Yaowalak Srisuwan; Mangkorn Srisa-ard; Chaiyasit Sittiwet; Yodthong Baimark; Nual- Anong Narkkong; Chirapha Butiman

2008-01-01

91

Tympanic membrane repair using silk fibroin and acellular collagen scaffolds.  

UK PubMed Central (United Kingdom)

OBJECTIVES/HYPOTHESIS: To evaluate the efficacy of silk fibroin scaffolds (SFS) and acellular collagen scaffolds (ACS) for the repair of tympanic membrane (TM) in a guinea pig acute perforation model. STUDY DESIGN: Experimental animal research. METHODS: Seventy-two albino guinea pigs underwent perforation of the right TM and were divided into four experimental groups (n = 18). The perforations were repaired with SFS, ACS, and paper patch using onlay myringoplasty, or they were allowed to heal spontaneously (control). An additional group of 10 guinea pigs without perforation or scaffold was allocated as a normal TM group. Guinea pigs in each experimental group (n = 6) were evaluated at 7, 14, and 28 days following surgery. TM structural healing was evaluated by otomicroscopy and histology, and functional hearing was analyzed by auditory brainstem responses (ABR). Prior to the study, mechanical properties of SFS and ACS were investigated. RESULTS: Tensile strength and elasticity of SFS and ACS were within the known range for human TM. Based on otologic and histologic evaluation, TMs treated with SFS or ACS showed complete closure of the perforation at an earlier stage, with a trilaminar structure and more uniform thickness compared to paper patch and control treated groups. ABR assessment demonstrated that SFS or ACS treatment facilitated a faster restoration of hearing function compared to paper patch and control groups. CONCLUSION: The results of this study show that SFS and ACS are effective graft materials and may be utilized as alternatives to current grafts for TM repair.

Shen Y; Redmond SL; Teh BM; Yan S; Wang Y; Atlas MD; Dilley RJ; Zheng M; Marano RJ

2013-08-01

92

Fabrication of PLGA scaffolds containing silk fibroin scaffolds for tissue engineering applications.  

UK PubMed Central (United Kingdom)

The present study deals with the fabrication of Poly(lactic-co-glycolic acid) (PLGA) scaffolds modified with silk fibroin for biomedical application. The PLGA solutions were added with salt particles and pressed with high pressures; which were further subjected to salt leaching resulting in the creation of large sized pores in the PLGA scaffolds. To fill up these pores, 2, 4 and 8% of silk solutions were added, however, the addition created extra small sized pores. The scaffolds were characterized by various state of techniques; the scanning electronic microcopy (SEM) revealed the large sized pores in the pristine scaffold can be tailored into smaller architecture by the addition of silk fibroin. The contact angle measurements confirmed the introduction of silk helped to change the hydrophobic nature of PLGA into hydrophilic, which is the main constrain for PLGA. The mechanical properties of scaffold can be easily improved by applying the higher amounts of silk into the scaffolds. The thermal gravimetric analyses (TGA) and fourier transform infrared spectroscopy (FTIR) confirmed the presence of silk fibroin in scaffolds. The cell viability and cell attachment was checked by culturing the scaffolds with NIH 3T3 fibroblasts and chondrocytes. Furthermore, these results revealed the introduction of silk had significant impact on the viability of fibroblast also had a good affinity for cell attachment and infiltration of human chondrocytes in scaffolds after culturing the cells for 2 and 5 weeks of time.

Ju HW; Sheikh FA; Moon BM; Park HJ; Lee OJ; Kim JH; Eun JJ; Khang G; Park CH

2013-09-01

93

In vitro and in vivo release of basic fibroblast growth factor using a silk fibroin scaffold as delivery carrier.  

UK PubMed Central (United Kingdom)

Two different solvents were used to prepare two types of silk fibroin scaffolds via the salt-leaching technique, i.e., hexafluoroisopropanol (HFIP) and water. The in vitro release study suggests that the opposite charge between the silk fibroin and basic fibroblast growth factor (bFGF) at physiological pH rendered them to form a complex, and the difference in the solvents used to produce the silk fibroin scaffold did not affect the affinity of silk fibroin to bFGF. However, a higher degradation rate of the aqueous-derived silk fibroin scaffolds provided faster in vitro release kinetics of the bFGF, as compared to the HFIP-derived scaffolds. From the in vivo studies, the use of silk fibroin scaffolds as the carrier matrix enabled the control of the in vivo release of bFGF in a sustained fashion over two weeks, while the majority of the bFGF disappeared within one day after the injection of the bFGF in soluble form. In addition, the in vivo release of bFGF from the silk fibroin scaffolds was not affected by the mode of processing due to their similar degradation behavior in vivo.

Wongpanit P; Ueda H; Tabata Y; Rujiravanit R

2010-01-01

94

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-04-15

95

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-01

96

Enzymatic degradation behavior and cytocompatibility of silk fibroin–starch–chitosan conjugate membranes  

International Nuclear Information System (INIS)

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 ?-amylase was more notable when the starch concentration was the highest at 30 wt.%. The conjugates were resistant to the degradation by protease and lysozyme except for the conjugates with the lowest starch concentration. After 10 days of cell culture, the proliferation of osteoblast-like cells (SaOS-2) was stimulated significantly by higher fibroin compositions and the DNA synthesis on the conjugate with the highest fibroin (30 wt.%) was about two times more compared to the native chitosan. The light microscopy and the image analysis results showed that the cell area and the lengths were decreased significantly with higher fibroin/chitosan ratio. The study proved that the conjugation of fibroin and starch with the chitosan based biomaterials by the use of non-toxic reductive alkylation crosslinking significantly improved the cytocompatibility and modulated the biodegradation, respectively. - Highlights: ? Silk fibroin, starch and chitosan conjugates were prepared by reductive alkylation. ? The enzymatic biodegradation and the cytocompatibility of conjugates were tested. ? The conjugate with 30% starch composition was degraded by ?-amylase significantly. ? Higher starch composition in conjugates prevented protease and lysozyme degradation. ? Fibroin incorporation effectively increased the cell proliferation of conjugates.

2012-08-01

97

Memory-Enhancing Effects of Silk Fibroin-Derived Peptides in Scopolamine-Treated Mice.  

UK PubMed Central (United Kingdom)

Although enzyme hydrolyzed silk fibroin has been reported to enhance cognitive function before, it has been still unknown which peptides can improve memory. Here we report that amino acid sequences of 3 novel peptides were identified from fibroin hydrolysate. Fibroin hydrolysate was obtained by hydrolyzed with protease after partial hydrolysis with 5M CaCl2. Synthesized peptides derived from these sequences improve scopolamine induced memory impairments in mice. We confirmed this hydrolysate had effects that improved learning and memory abilities by performing Rey-Kim test. From this hydrolysate of silk fibroin, amino acid sequences of 8 peptides were identified by LC-MS/MS. 3 peptides (GAGAGTGSSGFGPY, GAGAGSGAGSGAGAGSGAGAGY, and SGAGSGAGAGSGAGAGSGA) were synthesized to investigate whether these peptides could improve memory. Passive avoidance test and Morris water maze test were performed, and all peptides showed memory enhancing abilities on scopolamine induced memory impairments in mice. In this study, we identified that 3 novel peptides that could improve memory, and that silk fibroin hydrolysate was a mixture of various active peptides that could enhance memory.

Kang YK; Lee W; Kang B; Kang H

2013-09-01

98

Preparation and characterization of ethanol-treated silk fibroin dense membranes for biomaterials application using waste silk fibers as raw material.  

UK PubMed Central (United Kingdom)

The possibility of producing valued devices from low cost natural resources is a subject of broad interest. The present study explores the preparation and characterization of silk fibroin dense membranes using waste silk fibers from textile processing. Morphology, crystallinity, thermal resistance and cytotoxicity of membranes as well as the changes on the secondary structure of silk fibroin were analyzed after undergoing treatment with ethanol. Membranes presented amorphous patterns as determined via X-ray diffraction. The secondary structure of silk fibroin on dense membranes was either random coil (silk I) or beta-sheet (silk II), before and after ethanol treatment, respectively. The sterilized membranes presented no cytotoxicity to endothelial cells during in vitro assays. This fact stresses the material potential to be used in the fabrication of biomaterials, as coatings of cardiovascular devices and as membranes for wound dressing or drug delivery systems.

Nogueira GM; Rodas AC; Leite CA; Giles C; Higa OZ; Polakiewicz B; Beppu MM

2010-11-01

99

Preparation and characterization of ethanol-treated silk fibroin dense membranes for biomaterials application using waste silk fibers as raw material.  

Science.gov (United States)

The possibility of producing valued devices from low cost natural resources is a subject of broad interest. The present study explores the preparation and characterization of silk fibroin dense membranes using waste silk fibers from textile processing. Morphology, crystallinity, thermal resistance and cytotoxicity of membranes as well as the changes on the secondary structure of silk fibroin were analyzed after undergoing treatment with ethanol. Membranes presented amorphous patterns as determined via X-ray diffraction. The secondary structure of silk fibroin on dense membranes was either random coil (silk I) or beta-sheet (silk II), before and after ethanol treatment, respectively. The sterilized membranes presented no cytotoxicity to endothelial cells during in vitro assays. This fact stresses the material potential to be used in the fabrication of biomaterials, as coatings of cardiovascular devices and as membranes for wound dressing or drug delivery systems. PMID:20598877

Nogueira, Grínia M; Rodas, Andrea C D; Leite, Carlos A P; Giles, Carlos; Higa, Olga Z; Polakiewicz, Bronislaw; Beppu, Marisa M

2010-07-03

100

Bombyx mori silk fibroin scaffolds for bone regeneration studied by bone differentiation experiment.  

UK PubMed Central (United Kingdom)

Bombyx mori silk fibroin (SF) shows remarkably earlier calcification than bovine serum albumin, indicating advantage of the SF scaffold for bone regeneration. We provide evidence for the first time, that SF not only activate early differentiation markers of osteoblasts, but also activate expression of the late differentiation markers.

Miyamoto S; Koyanagi R; Nakazawa Y; Nagano A; Abiko Y; Inada M; Miyaura C; Asakura T

2013-05-01

 
 
 
 
101

Preparation of silk fibroin–poly(ethylene glycol) conjugate films through click chemistry  

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Azide silk fibroin (azido SF) and alkyne terminal poly(ethylene glycol) (PEG) 2000 (acetylene-terminal PEG 2000) were synthesized. Azido SF was reacted with acetylene-terminal PEG 2000 to produce films via a copper-mediated 1,3-cycloaddition (‘click’ chemistry) generating a triazole linkage as the n...

Sampaio, Sandra; Miranda, Teresa; Santos, Jorge Gomes; Soares, Graça M. B.

102

Quantitative evaluation of fibroblast migration on a silk fibroin surface and TGFBI gene expression.  

UK PubMed Central (United Kingdom)

Cell migration plays important roles in natural processes involving embryonic development, inflammation, wound healing, cancer metastasis and angiogenesis. Cell migration on various biomaterials is also believed to improve the rate of wound healing and implant therapies in the tissue-engineering field. This study measured the distance traversed, or mileage, of mouse fibroblasts on a silk fibroin surface. Fibroblasts on the fibroin surface moved with better progress during 24 h than cells on collagen or fibronectin surfaces. Results obtained by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) revealed that fibroblasts on the fibroin surface expressed transforming growth factor ?-induced protein (TGFBI), which is an extracellular matrix (ECM) protein, stronger than on other surfaces in the early cell-culture stages. These results demonstrate that the fibroin surface shows higher potential to enhance cell migration and the production of ECM than a collagen or fibronectin surface.

Hashimoto T; Kojima K; Otaka A; Takeda YS; Tomita N; Tamada Y

2013-01-01

103

Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization  

International Nuclear Information System (INIS)

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl2, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the ?-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and ?-helix form (Silk I) into anti-parallel ?-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, 13C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with ?-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk fibroin in aqueous solution. It is possible that the silk protein nanoparticles are potentially useful in biomaterials such as cosmetics, anti-UV skincare products, industrial materials and surface improving materials, especially in enzyme/drug delivery system as vehicle.

2007-01-01

104

Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization  

Energy Technology Data Exchange (ETDEWEB)

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into anti-parallel {beta}-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, {sup 13}C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with {beta}-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk fibroin in aqueous solution. It is possible that the silk protein nanoparticles are potentially useful in biomaterials such as cosmetics, anti-UV skincare products, industrial materials and surface improving materials, especially in enzyme/drug delivery system as vehicle.

Zhang Yuqing, E-mail: yqzhang@public1.sz.js.cn; Shen Weide; Xiang Ruli [Soochow University, Silk Biotechnol. Lab., School of Life Science (China); Zhuge Lanjian; Gao Weijian; Wang Wenbao [Soochow University, Analytical Center (China)

2007-10-15

105

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

Energy Technology Data Exchange (ETDEWEB)

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

Yamada, Kazushi; Tsuboi, Yasuyuki; Itaya, Akira

2003-09-01

106

Development of electrospun beaded fibers from Thai silk fibroin and gelatin for controlled release application.  

UK PubMed Central (United Kingdom)

Thai silk fibroin and gelatin are attractive biomaterials for tissue engineering and controlled release applications due to their biocompatibility, biodegradability, and bioactive properties. The development of electrospun fiber mats from silk fibroin and gelatin were reported previously. However, burst drug release from such fiber mats remained the problem. In this study, the formation of beads on the fibers aiming to be used for the sustained release of drug was of our interest. The beaded fiber mats were fabricated using electrospinning technique by controlling the solution concentration, weight blending ratio of Thai silk fibroin/gelatin blend, and applied voltage. It was found that the optimal conditions including the solution concentration and the weight blending ratio of Thai silk fibroin/gelatin at 8-10% (w/v) and 70/30, respectively, with the applied voltage at 18 kV provided the fibers with homogeneous formation of beads. Then, the beaded fiber mats obtained were crosslinked by the reaction of carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS). Methylene blue as a model active compound was loaded on the fiber mats. The release test of methylene blue from the beaded fiber mats was carried out in comparison to that of the smooth fiber mats without beads. It was found that the beaded fiber mats could prolong the release of methylene blue, comparing to the smooth fiber mats without beads. This was possibly due to the beaded fiber mats that would absorb and retain higher amount of methylene blue than the fiber mats without beads. Thai silk fibroin/gelatin beaded fiber mats were established as an effective carrier for the controlled release applications.

Somvipart S; Kanokpanont S; Rangkupan R; Ratanavaraporn J; Damrongsakkul S

2013-04-01

107

The expression analysis of silk gland-enriched intermediate-size non-coding RNAs in silkworm Bombyx mori.  

UK PubMed Central (United Kingdom)

Small non-protein coding RNAs (ncRNAs) play important roles in development, stress response and other cellular processes. Silkworm is an important model for studies on insect genetics and control of Lepidopterous pests. We have previously identified 189 novel intermediate-size ncRNAs in silkworm Bombyx mori, including 40 ncRNAs that showed altered expression in different developmental stages. Here we characterized the functions of these 40 ncRNAs by measuring their expressions in six tissues of the fifth instar larvae using Northern blot and real-time PCR assays. We identified 9 ncRNAs (4 snoRNAs and 5 unclassified ncRNAs) that were enriched in silk gland, including four ncRNAs that showed silk gland-specific expression. We further showed that 3 of 9 silk gland-enriched ncRNAs were predominantly expressed in the anterior silk gland, whereas another 3 ncRNAs were highly accumulated in the posterior silk gland, suggesting that they may play different roles in fibroin synthesis. Furthermore, an unclassified ncRNA, Bm-152, exhibited converse expression pattern with its antisense host gene gartenzwerg in diverse tissues, and might regulate the expression of gartenzwerg through RNA-protein complex. In addition, two silk gland-enriched ncRNAs Bm-102 and Bm-159 can be found in histone modification complex, which indicated that they might play roles through epigenetic modifications. Taken together, we provided the first expression and preliminary functional analysis of silk-gland enriched ncRNAs, which will help understand the molecular mechanism of silk-gland development and fibroin synthesis. This article is protected by copyright. All rights reserved.

Li D; Liu Z; Huang L; Jiang Q; Zhang K; Qiao H; Jiao Z; Yao L; Liu R; Kan Y

2013-10-01

108

Utilising silk fibroin membranes as scaffolds for the growth of tympanic membrane keratinocytes, and application to myringoplasty surgery.  

UK PubMed Central (United Kingdom)

BACKGROUND: Chronic tympanic membrane perforations can cause significant morbidity. The term myringoplasty describes the operation used to close such perforations. A variety of graft materials are available for use in myringoplasty, but all have limitations and few studies report post-operative hearing outcomes. Recently, the biomedical applications of silk fibroin protein have been studied. This material's biocompatibility, biodegradability and ability to act as a scaffold to support cell growth prompted an investigation of its interaction with human tympanic membrane keratinocytes. METHODS AND MATERIALS: Silk fibroin membranes were prepared and human tympanic membrane keratinocytes cultured. Keratinocytes were seeded onto the membranes and immunostained for a number of relevant protein markers relating to cell proliferation, adhesion and specific epithelial differentiation. RESULTS: The silk fibroin scaffolds successfully supported the growth and adhesion of keratinocytes, whilst also maintaining their cell lineage. CONCLUSION: The properties of silk fibroin make it an attractive option for further research, as a potential alternative graft in myringoplasty.

Levin B; Redmond SL; Rajkhowa R; Eikelboom RH; Atlas MD; Marano RJ

2013-01-01

109

Preparation and characterization of regenerated Bombyx mori silk fibroin fiber with high strength  

Directory of Open Access Journals (Sweden)

Full Text Available Regenerated Bombyx mori silk fibers were spun from hexafluoro-iso- propanol solution of silk fibroin sponge in methanol used as a coagulant solvent and then elongated in water. The stress-strain curves of the regenerated fibers changed dramatically depending on the draw ratio and the structure was studied by 13C CP/MAS NMR and X-ray diffraction methods. The patterns of 13C CP/MAS NMR spectra of two regenerated fibers with different draw ratios (1× and 3×) and native silk fiber are all ?-sheet structure although the fraction of random coil/distorted ?-turn decreases in the order of 1×, 3× and native fiber gradually. On the other hand, azimuthal scans of their X-ray fiber patterns changed remarkably with increasing the draw ratio. This indicates that long-range orientation of the fibroin chain changes remarkably during the drawing process, but the short-range local structure does not change significantly. Regenerated silk fiber with a draw ratio of 3× is a fiber with high strength which is comparable with that of natural silk fiber. The regenerated fiber is also more degradable than natural silk fiber in enzyme solution in vitro.

2008-01-01

110

Silk fibroin film from non-mulberry tropical tasar silkworms: A novel substrate for in vitro fibroblast culture.  

Science.gov (United States)

The silk protein fibroin, isolated from the cocoon of the domesticated mulberry silkworm, Bombyx mori, is used extensively in biomaterial design and in cell and tissue culture. We report here for the first time the potential application of fibroin obtained from the cocoon of non-mulberry tropical silkworm, Antheraea mylitta, as a substrate for in vitro cell culture. The mechanical strength of A. mylitta silk fibers indicates a stronger thread composition. The contact angle of A. mylitta fibroin films suggests that it has lower hydrophilicity and lower solubility in organic solvents compared to B. mori fibroin films. Retention of a secondary structure of fibroin in both A. mylitta and B. mori films is confirmed by Fourier transform infrared analysis. The adherence, growth and proliferation patterns of feline fibroblast cells on A. mylitta fibroin films suggest that this kind of film has a greater ability to support cell growth than B. mori fibroin films and is comparable to that of control. This study demonstrates that, as well as being non-toxic to dermal fibroblast cells, non-mulberry fibroin might be a useful alternative substrate to the more common B. mori fibroin for a variety of biomedical applications. PMID:18676188

Acharya, Chitrangada; Ghosh, Sudip K; Kundu, S C

2008-07-18

111

Silk fibroin film from non-mulberry tropical tasar silkworms: A novel substrate for in vitro fibroblast culture.  

UK PubMed Central (United Kingdom)

The silk protein fibroin, isolated from the cocoon of the domesticated mulberry silkworm, Bombyx mori, is used extensively in biomaterial design and in cell and tissue culture. We report here for the first time the potential application of fibroin obtained from the cocoon of non-mulberry tropical silkworm, Antheraea mylitta, as a substrate for in vitro cell culture. The mechanical strength of A. mylitta silk fibers indicates a stronger thread composition. The contact angle of A. mylitta fibroin films suggests that it has lower hydrophilicity and lower solubility in organic solvents compared to B. mori fibroin films. Retention of a secondary structure of fibroin in both A. mylitta and B. mori films is confirmed by Fourier transform infrared analysis. The adherence, growth and proliferation patterns of feline fibroblast cells on A. mylitta fibroin films suggest that this kind of film has a greater ability to support cell growth than B. mori fibroin films and is comparable to that of control. This study demonstrates that, as well as being non-toxic to dermal fibroblast cells, non-mulberry fibroin might be a useful alternative substrate to the more common B. mori fibroin for a variety of biomedical applications.

Acharya C; Ghosh SK; Kundu SC

2009-01-01

112

Hydrogen-bonded Multilayers of Silk Fibroin: From Coatings to Cell-mimicking Shaped Microcontainers.  

UK PubMed Central (United Kingdom)

We present a novel type of all-aqueous non-ionic layer-by-layer films of silk fibroin with synthetic macromolecules and a natural polyphenol. We found the multilayer growth and stability to be strongly pH-dependent. Silk assembled with poly(methacrylic) and tannic acids at pH=3.5 disintegrated at pH~5; while silk/poly(N-vinylcaprolactam) interactions were stable at low and high pH values but resulting in thinner films at high pH. The results suggest that the intermolecular interactions are primary driven by hydrogen bonding with a considerable contribution of hydrophobic forces. We also demonstrated that cubical, spherical and platelet capsules with silk-containing walls can be constructed using particulate sacrificial templates. This work sets a foundation for future explorations of natural and synthetic macromolecules assemblies as biomimetic materials with tunable properties.

Kozlovskaya V; Baggett J; Godin B; Liu X; Kharlampieva E

2012-02-01

113

Print head design and control for electrohydrodynamic printing of silk fibroin.  

UK PubMed Central (United Kingdom)

This study investigates the effect of print head design on the electrohydrodynamic printed resolution of silk fibroin. Needles with large orifices measuring at 800 ?m were used to build five different print heads. The print heads were manufactured, tested, and optimized using four different silk fibroin solution concentrations of 10 wt.%, 15 wt.%, 20 wt.%, and 22 wt.% at applied voltages that ranged from 10 to 20 kV with two different flow rates of 1.5 ?l/min and 2.0 ?l/min. Each print head design behaved in a unique manner in terms of printed line characteristics as the flow rate, voltage and concentration were varied. The highest printed resolution of the order of 1 ?m was achieved using the pinhole reservoir print head. Possible explanations for each of the observed behaviors and design criteria for future print heads are discussed.

Hashimdeen SH; Miodownik M; Edirisinghe MJ

2013-08-01

114

Drug loading and release on tumor cells using silk fibroin-albumin nanoparticles as carriers.  

UK PubMed Central (United Kingdom)

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.

Subia B; Kundu SC

2013-01-01

115

Print head design and control for electrohydrodynamic printing of silk fibroin.  

Science.gov (United States)

This study investigates the effect of print head design on the electrohydrodynamic printed resolution of silk fibroin. Needles with large orifices measuring at 800 ?m were used to build five different print heads. The print heads were manufactured, tested, and optimized using four different silk fibroin solution concentrations of 10 wt.%, 15 wt.%, 20 wt.%, and 22 wt.% at applied voltages that ranged from 10 to 20 kV with two different flow rates of 1.5 ?l/min and 2.0 ?l/min. Each print head design behaved in a unique manner in terms of printed line characteristics as the flow rate, voltage and concentration were varied. The highest printed resolution of the order of 1 ?m was achieved using the pinhole reservoir print head. Possible explanations for each of the observed behaviors and design criteria for future print heads are discussed. PMID:23706215

Hashimdeen, S H; Miodownik, M; Edirisinghe, M J

2013-04-11

116

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

International Nuclear Information System (INIS)

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

2011-01-01

117

Evaluation of stretched electrospun silk fibroin matrices seeded with urothelial cells for urethra reconstruction.  

UK PubMed Central (United Kingdom)

BACKGROUND: We investigated the feasibility of urethral reconstruction using stretched electrospun silk fibroin matrices. MATERIALS AND METHODS: A novel electrospun silk fibroin matrix was prepared. The structure of the material was assessed by scanning electron microscopy and a porosity test. Canine urothelial cells were isolated, expanded, and seeded onto the material for 1 wk to obtain a tissue-engineered graft. The tissue-engineered graft was assessed using hematoxylin and eosin staining and scanning electron microscopy. A dorsal urethral mucosal defect was created in nine female beagle dogs. In the experimental group, tissue-engineered mucosa was used to repair urethra mucosa defects in six dogs. No substitute was used in the three dogs of the control group. Retrograde urethrography was performed at 1, 2, and 6 mo after grafting. The urethral grafts were analyzed grossly and histologically. RESULTS: Scanning electron microscope and a porosity test revealed that the material had a three-dimensional porous structure. Urothelial cells grew on the material and showed good biocompatibility with the stretched silk fibroin matrices. Canines implanted with tissue-engineered mucosa voided without difficulty. Retrograde urethrography revealed no signs of stricture. Histologic staining showed gradual epithelial cell development and stratified epithelial layers at 1, 2, and 6 mo. The canines in the control group showed difficulty in voiding. Retrograde urethrography showed urethra stricture. Histologic staining showed that no or only one layer of epithelial cells developed. A severe inflammatory reaction was also observed in the control group. CONCLUSIONS: Stretched electrospun silk fibroin matrices have good biocompatibility with urothelial cells, which could prove to be a potential material for use in urethra reconstruction.

Xie M; Song L; Wang J; Fan S; Zhang Y; Xu Y

2013-10-01

118

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

119

Fabrication of Chitosan/Silk Fibroin Composite Nanofibers for Wound-dressing Applications  

Directory of Open Access Journals (Sweden)

Full Text Available Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications.

Zeng-xiao Cai; Xiu-mei Mo; Kui-hua Zhang; Lin-peng Fan; An-lin Yin; Chuang-long He; Hong-sheng Wang

2010-01-01

120

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

UK PubMed Central (United Kingdom)

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

Guan L; Tian P; Ge H; Tang X; Zhang H; Du L; Liu P

2013-10-01

 
 
 
 
121

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

UK PubMed Central (United Kingdom)

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

Guan L; Tian P; Ge H; Tang X; Zhang H; Du L; Liu P

2013-05-01

122

Histochemical and ultrastructural evidence of lipid secretion by the silk gland of the sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae).  

UK PubMed Central (United Kingdom)

The silk gland in Lepidoptera larvae is responsible for the silk production used for shelter or cocoon construction. The secretion of fibroin and sericin by the different silk gland regions are well established. There are few attempts to detect lipid components in the insect silk secretion, although the presence of such element may contribute to the resistance of the shelter to wet environment. This study characterizes the glandular region and detects the presence of lipid components in the secretion of the silk gland of Diatraea saccharalis(Fabricius). The silk gland was submitted to histochemical procedure for lipid detection or conventionally prepared for ultrastructural analyses. Lipid droplets were histochemically detected in both the apical cytoplasm of cell of the anterior region and in the lumen among the microvilli. Ultrastructural analyses of the anterior region showed lipid material, visualized as myelin-like structures within the vesicular Golgi complex and in the apical secretory globules, mixed up with the sericin; similar material was observed into the lumen, adjacent to the microvilli. Lipids were not detected in the cells neither in the lumen of the posterior region. Our results suggest that the silk produced by D. saccharalis has a minor lipid content that is secreted by the anterior region together with the sericin.

Victoriano E; Pinheiro DO; Gregório EA

2007-09-01

123

Histochemical and ultrastructural evidence of lipid secretion by the silk gland of the sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae).  

Science.gov (United States)

The silk gland in Lepidoptera larvae is responsible for the silk production used for shelter or cocoon construction. The secretion of fibroin and sericin by the different silk gland regions are well established. There are few attempts to detect lipid components in the insect silk secretion, although the presence of such element may contribute to the resistance of the shelter to wet environment. This study characterizes the glandular region and detects the presence of lipid components in the secretion of the silk gland of Diatraea saccharalis(Fabricius). The silk gland was submitted to histochemical procedure for lipid detection or conventionally prepared for ultrastructural analyses. Lipid droplets were histochemically detected in both the apical cytoplasm of cell of the anterior region and in the lumen among the microvilli. Ultrastructural analyses of the anterior region showed lipid material, visualized as myelin-like structures within the vesicular Golgi complex and in the apical secretory globules, mixed up with the sericin; similar material was observed into the lumen, adjacent to the microvilli. Lipids were not detected in the cells neither in the lumen of the posterior region. Our results suggest that the silk produced by D. saccharalis has a minor lipid content that is secreted by the anterior region together with the sericin. PMID:18060296

Victoriano, Eliane; Pinheiro, Daniela O; Gregório, Elisa A

124

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-06-01

125

Method for extracting fibroin peptide from mulberry silk  

UK PubMed Central (United Kingdom)

The invention discloses a method for extracting silk peptide from cocoon fiber, which belongs to the technical field of preparation of the silk peptide. The method comprises the following steps: the cocoon fiber is added into a Na2CO3 solution for refining, filtrated and added into a CaCl2 solution for dissolution protease for silk dissolution solution obtained after dissolution undergoes enzymatic hydrolysis reaction after ultrafiltraiotn and nano-filtration separation of digest, a feed liquid is obtained and the silk peptide powder is obtained after spray drying of the feed liquid. The method has the advantages that ACE inhibitory polypeptide is enriched through ultrafiltraiotn and nano-filtration separation of the digest the efficiency of removing CaCl2 salt is high the method has the advantages of large processing capacity, mild separation condition, simple flow, low energy consumption and so on and the industrial production is easy to realize.

FENGJUAN ZHOU; ZHAOHUI XUE; XIAOHONG KOU

126

Differential expression of the fibroin gene in developmental stages of silkworm, Antheraea mylitta (Saturniidae).  

Science.gov (United States)

Fibroin gene expression during the larval developmental stages of the Saturniid silkworm, Antheraea mylitta, was analyzed. Northern blot analysis of larval silk gland total RNA using the fibroin gene as a probe showed that fibroin is expressed in the intermoult stages and repressed during the moulting stages. Abundance of fibroin transcripts gradually increased from the third to fifth intermoult stage, reaching a peak in the fifth intermoult. Transcripts declined during the early spinning stage. Western blot analysis of fibroin protein production with anti-fibroin antibody confirmed the differential fibroin expression, in accordance with fibroin mRNA synthesis. Dot blot hybridization of genomic DNA isolated from each larval developmental stage with the labelled fibroin gene showed that at the genomic level, the relative concentration of the fibroin gene was constant throughout the developmental stages. Our data confirm that fibroin gene expression in A. mylitta, like in B. mori, is transcriptionally controlled and shows differential temporal variations. PMID:11337263

Datta, A; Ghosh, A K; Kundu, S C

2001-05-01

127

Differential expression of the fibroin gene in developmental stages of silkworm, Antheraea mylitta (Saturniidae).  

UK PubMed Central (United Kingdom)

Fibroin gene expression during the larval developmental stages of the Saturniid silkworm, Antheraea mylitta, was analyzed. Northern blot analysis of larval silk gland total RNA using the fibroin gene as a probe showed that fibroin is expressed in the intermoult stages and repressed during the moulting stages. Abundance of fibroin transcripts gradually increased from the third to fifth intermoult stage, reaching a peak in the fifth intermoult. Transcripts declined during the early spinning stage. Western blot analysis of fibroin protein production with anti-fibroin antibody confirmed the differential fibroin expression, in accordance with fibroin mRNA synthesis. Dot blot hybridization of genomic DNA isolated from each larval developmental stage with the labelled fibroin gene showed that at the genomic level, the relative concentration of the fibroin gene was constant throughout the developmental stages. Our data confirm that fibroin gene expression in A. mylitta, like in B. mori, is transcriptionally controlled and shows differential temporal variations.

Datta A; Ghosh AK; Kundu SC

2001-05-01

128

Silk fibroin films are a bio-active interface for neuroregenerative medicine.  

UK PubMed Central (United Kingdom)

Purpose: Biomaterials that enable the control of bioelectrical signals in neural cells have major potential for use in tissue engineering, targeted drug release or stem cell based neuroregenerative medicine. In this rapidly emerging area, particular attention is devoted to the engineering and use of interfaces that could be integrated in biocompatible electronic devices. In recent years, silk fibroin from Bombyx mori cocoon has been extensively studied for new biomedical applications, such as functional tissue engineering and drug delivery and in electronic devices intended for neuroregenerative medicine. However, achieving a thorough biocompatibility can be challenging because of the complex nature of the biological response to interaction with biomaterials. In particular an interface suitable for nerve regeneration should support neurite outgrowth and preserve/promote the functional recovery of neuronal cells (bio-functional interface), by enabling neuronal conduction of action potential. Moreover, attention should be given to modulation of bioelectrical activity of non-excitable (namely glial cells), in view of their central role in the inflammatory reaction occurring upon prothesic implantation at injury sites. ?On this basis our lab's activity was targeted to define the effect of bio-derived biomaterials thin films (as silk fibroin), on the growth and electrophysiologic properties of peripheral neurons and glial cells.?Methods: Silk fibroin was extracted and thin films were prepared by means of previously reported protocols. Primary cultures of dorsal root ganglion (DRG) neurons (1) and cortical astrocytes (2) were plated on those films. Morphometric analyses were performed by optical and confocal imaging. Functional analyses were performed by means of single cell whole cell patch-clamp.?Results: In our work we have demonstrated that SF films are a favorable substrate to support in vitro studies on neuron and astrocytes. In particular, SF 1) promote adhesion and neurite outgrowth of peripheral neuron culture in vitro 2) preserve the capability of these neuronal cells to fire. 3) Preserve bioelectrical properties of astrocytes. By functionalization with specific trophic molecules, we demonstrated that bioelectrical properties of astrocytes could be specifically modulated. Moreover, we showed that NGF-silk films enable increased neurite outgrowth and modulation of firing properties of cultured neurons. ?Conclusions: Silk fibroin is a biomaterial platform with major potential in neuroregenerative medicine, especially the Central and Peripheral Nervous System.

Benfenati V; Pistone A; Sagnella A; Stahl K; Camassa L; Gomis-Perez C; Toffanin S; Torp R; Kaplan DL; Ruani G; Omenetto FG; Zamboni R; Muccini M

2012-12-01

129

The application with tetramethyl pyrazine for antithrombogenicity improvement on silk fibroin surface  

Energy Technology Data Exchange (ETDEWEB)

Chuanxiongqin (tetramethyl pyrazine, TMPZ) is an active ingredient of the Chinese herb and was used to improve the anticoagulant activity of silk fibroin (SF). The side methyl of TMPZ was oxidized, and then linked to polyacrylic acid (PAA) via an ester bond. The prepared conjugate was further mixed with SF solutions at different ratios to make blend films. The resulting products were characterized by FTIR, UV spectrometer and X-ray photoelectron spectroscopy (XPS). The in vitro antithrombogenicity were evaluated by the activated partial thromboplastin time (APTT) and the prothrombin time (PT). It was shown that blend films had longer coagulation time than the pure SF film.

Lian Xiaojie [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Wang Song [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)], E-mail: wangsongbit@126.com; Xu Guoliang; Lin Nini; Li Qian; Zhu Hesun [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2008-11-15

130

In situ deposition of flower-like ZnO on silk fibroin fibers  

Energy Technology Data Exchange (ETDEWEB)

In this paper, a convenient biomineralization technique has been developed to form and assemble flower-like zinc oxide (ZnO) on silk fibroin fiber (SFF). Therein, SFF functions as supporting substrate and reactive sites for the in situ generation of ZnO particles. The photoluminescence (PL) of the resulting nanocomposite ZnO/SFF is investigated extensively. The PL peaks are mainly in the visible region (red), which is different from the usual ZnO region (green and violet). As-prepared ZnO/SFF nanocomposites could be useful in the medical field, photoelectron transfer devices, biomolecular detection, and antibacterial agents. (orig.)

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

2012-07-15

131

Study on the preparation of collagen-modified silk fibroin films and their properties  

Energy Technology Data Exchange (ETDEWEB)

Blended films were prepared from a silk fibroin (SF) solution by adding a small amount of type I collagen (<5%). The mechanical properties of the wet films modified by collagen were improved obviously. The elongation at break reached 42%, and the smaller contact angles revealed that modified films had better hydrophilicity. 1% heparin was also added to modify the SF films to further improve the in vitro antithrombogenecity. The internal structure of the modified SF films was investigated with scanning electron microscopy, x-ray diffraction and Fourier transform infrared attenuated total reflection spectroscopy. The result indicates that the addition of a small amount of collagen and heparin did not change their conformation.

Tang Yin; Cao Chuanbao; Ma Xilan; Chen Chen; Zhu Hesun [Research Center of Material Science, Beijing Institute of Technology, Bejing 100081 (China)

2006-12-01

132

The Dielectric Breakdown Strength of Regenerated Silk Fibroin Films as a Function of Protein Conformation.  

UK PubMed Central (United Kingdom)

Derived from Bombyx mori cocoons, regenerated silk fibroin (RSF) exhibits excellent biocompatibility, high toughness and tailorable biodegradability. Furthermore, RSF materials may be doped with a variety bioactive species, flexible, optically clear and easily patterned with nanoscale features. This unique combination of properties has led to increased interest in the use of RSF in sustainable and biocompatible electronic devices. In order to explore the applicability of this biopolymer to the development of future bioelectronics, the dielectric breakdown strength (Ebd) of RSF thin films was quantified as a function of protein conformation. The application of processing conditions that increased ?-sheet content and produced films in the silk II structure resulted in RSF materials with improved Ebd with values reaching up to 400V/?m.

Dickerson MB; Fillery SP; Singh KM; Martinick K; Drummy LF; Durstock MF; Vaia RA; Omenetto FG; Kaplan DL; Naik RR; Koerner H

2013-08-01

133

Dielectric breakdown strength of regenerated silk fibroin films as a function of protein conformation.  

UK PubMed Central (United Kingdom)

Derived from Bombyx mori cocoons, regenerated silk fibroin (RSF) exhibits excellent biocompatibility, high toughness, and tailorable biodegradability. Additionally, RSF materials are flexible, optically clear, easily patterned with nanoscale features, and may be doped with a variety bioactive species. This unique combination of properties has led to increased interest in the use of RSF in sustainable and biocompatible electronic devices. In order to explore the applicability of this biopolymer to the development of future bioelectronics, the dielectric breakdown strength (Ebd) of RSF thin films was quantified as a function of protein conformation. The application of processing conditions that increased ?-sheet content (as determined by FTIR analysis) and produced films in the silk II structure resulted in RSF materials with improved Ebd with values reaching up to 400 V/?m.

Dickerson MB; Fillery SP; Koerner H; Singh KM; Martinick K; Drummy LF; Durstock MF; Vaia RA; Omenetto FG; Kaplan DL; Naik RR

2013-10-01

134

Variation of the effect of calcium phosphate enhancement of implanted silk fibroin ligament bone integration.  

UK PubMed Central (United Kingdom)

In this article, low crystallinity hydroxyapatite (LHA) is developed and utilized to modify silk fibroin scaffolds which are applied to repair bone/ligament defects successfully. It can promote osteogenesis which is authenticated through in vitro and in vivo tests. The scaffold is an efficient carrier, supporting cell proliferation and differentiation. Meanwhile, cytocompatibility and osteoblastic gene expressions (RUNX2 and osteocalcin, for example) of rabbit's bone marrow derived mesenchymal stem cells (MSCs) are significantly boosted on LHA/silk scaffold. Further, for animal trial, almost 60% of bone volume and 80% of original mechanical strength are recovered after 4 months' bone/ligament regeneration in bone tunnel of rabbit model, where significant amount of bone tissue regeneration is also confirmed by data of histological evaluation and micro computed tomography (?-CT). Hence, the invented scaffold is applicable for ligament/bone regeneration in future lager animal and clinical trials.

Shi P; Teh TK; Toh SL; Goh JC

2013-08-01

135

Silk fibroin protein from mulberry and non-mulberry silkworms: cytotoxicity, biocompatibility and kinetics of L929 murine fibroblast adhesion.  

Science.gov (United States)

Silks fibers and films fabricated from fibroin protein of domesticated mulberry silkworm cocoon have been traditionally utilized as sutures in surgery and recently as biomaterial films respectively. Here, we explore the possibility of application of silk fibroin protein from non-mulberry silkworm cocoon as a potential biomaterial aid. In terms of direct inflammatory potential, fibroin proteins from Antheraea mylitta and Bombyx mori are immunologically inert and invoke minimal immune response. Stimulation of murine peritoneal macrophages and RAW 264.7 murine macrophages by these fibroin proteins both in solution and in the form of films assayed in terms of nitric oxide and TNFalpha production showed comparable stimulation as in collagen. Kinetics of adhesion of L929 murine fibroblasts, for biocompatibility evaluation, monitored every 4 h from seeding and studied over a period of 24 h, reveal A. mylitta fibroin film to be a better substrate in terms of rapid and easier cellularization. Cell viability studies by MTT assay and flow cytometric analyses indicate the ability of fibroin matrices to support cell growth and proliferation comparable to collagen for long-term culture. This matrix may have potential to serve in those injuries where rapid cellularization is essential. PMID:18322779

Acharya, Chitrangada; Ghosh, Sudip K; Kundu, S C

2008-03-06

136

Silk fibroin protein from mulberry and non-mulberry silkworms: cytotoxicity, biocompatibility and kinetics of L929 murine fibroblast adhesion.  

UK PubMed Central (United Kingdom)

Silks fibers and films fabricated from fibroin protein of domesticated mulberry silkworm cocoon have been traditionally utilized as sutures in surgery and recently as biomaterial films respectively. Here, we explore the possibility of application of silk fibroin protein from non-mulberry silkworm cocoon as a potential biomaterial aid. In terms of direct inflammatory potential, fibroin proteins from Antheraea mylitta and Bombyx mori are immunologically inert and invoke minimal immune response. Stimulation of murine peritoneal macrophages and RAW 264.7 murine macrophages by these fibroin proteins both in solution and in the form of films assayed in terms of nitric oxide and TNFalpha production showed comparable stimulation as in collagen. Kinetics of adhesion of L929 murine fibroblasts, for biocompatibility evaluation, monitored every 4 h from seeding and studied over a period of 24 h, reveal A. mylitta fibroin film to be a better substrate in terms of rapid and easier cellularization. Cell viability studies by MTT assay and flow cytometric analyses indicate the ability of fibroin matrices to support cell growth and proliferation comparable to collagen for long-term culture. This matrix may have potential to serve in those injuries where rapid cellularization is essential.

Acharya C; Ghosh SK; Kundu SC

2008-08-01

137

The synergistic effects of 3-D porous silk fibroin matrix scaffold properties and hydrodynamic environment in cartilage tissue regeneration.  

UK PubMed Central (United Kingdom)

Autologous cell-based tissue engineering using three-dimensional porous scaffolds has provided a good option for the repair of cartilage defects. Silk fibroin-based scaffolds are naturally degradable materials with excellent biocompatibility and robust mechanical properties, indicating potential applications in cartilage tissue engineering. In this study, silk fibroin scaffolds prepared by freeze-drying (FD) and salt-leaching (SL300 and SL500) were fully characterized and used to study the effects of silk fibroin scaffold properties on chondrocyte attachment, proliferation and differentiation. The synergistic effects of scaffold properties and hydrodynamic environment generated by in vitro rocking culture were also investigated using static cultures as control. FD scaffolds with small pore size and lower porosity increased cell attachment but inhibited cell penetration and limited cell proliferation and differentiation. In contrast, SL scaffolds displaying a bigger pore size, higher porosity and crystallinity resulted in homogenous cell distribution, increasing cell proliferation and advanced chondrocyte differentiation in terms of their spherical morphology, predominant chondrogenic gene expression and abundant cartilaginous extracellular matrix production. A hydrodynamic environment was beneficial to chondrocyte proliferation, differentiation, and integrin gene expression in a pore size dependent manner with superior cartilage matrix production but limited hypertrophic differentiation obtained using chondrocyte-seeded SL500 scaffolds. Integrin alpha5beta1 might mediate these effects. Chondrocyte/SL500 silk fibroin constructs obtained under in vitro rocking culture might serve as an excellent implant for in vivo cartilage defect reparation.

Wang Y; Bella E; Lee CS; Migliaresi C; Pelcastre L; Schwartz Z; Boyan BD; Motta A

2010-06-01

138

Silk fibroin/hyaluronic acid 3D matrices for cartilage tissue engineering.  

UK PubMed Central (United Kingdom)

In spite of commercially available products, the complete and sustained repair of damaged articular cartilage still presents various challenges. Among biomaterials proposed for cartilage repair, silk fibroin (SF) has been recently proposed as a material template for porous scaffolds cultured with chondrocytes and investigated in static and dynamic conditions. In addition to fibroin-based constructs, literature has reported that the combination of hyaluronic acid (HA) with other scaffold materials can protect the chondral phenotype and the cells in vitro response to the scaffold. In this study, the effect of the addition of HA on the physical properties of SF sponges, with and without cross-linking with genipin, was investigated. Salt-leached scaffolds were characterized in terms of morphology and structural and physical properties, as well as mechanical performance. Un-cross-linked sponges resulted in the physical separation of highly hydrophilic HA from the SF, while cross-linking prevented this phenomenon, resulting in a homogeneous blend. The presence of HA also influenced fibroin crystallinity and tended to decrease the cross-linking degree of the scaffolds when compared to the pure SF material.

Foss C; Merzari E; Migliaresi C; Motta A

2013-01-01

139

Silk fibroin/hyaluronic acid 3D matrices for cartilage tissue engineering.  

Science.gov (United States)

In spite of commercially available products, the complete and sustained repair of damaged articular cartilage still presents various challenges. Among biomaterials proposed for cartilage repair, silk fibroin (SF) has been recently proposed as a material template for porous scaffolds cultured with chondrocytes and investigated in static and dynamic conditions. In addition to fibroin-based constructs, literature has reported that the combination of hyaluronic acid (HA) with other scaffold materials can protect the chondral phenotype and the cells in vitro response to the scaffold. In this study, the effect of the addition of HA on the physical properties of SF sponges, with and without cross-linking with genipin, was investigated. Salt-leached scaffolds were characterized in terms of morphology and structural and physical properties, as well as mechanical performance. Un-cross-linked sponges resulted in the physical separation of highly hydrophilic HA from the SF, while cross-linking prevented this phenomenon, resulting in a homogeneous blend. The presence of HA also influenced fibroin crystallinity and tended to decrease the cross-linking degree of the scaffolds when compared to the pure SF material. PMID:23134349

Foss, Cristina; Merzari, Enrico; Migliaresi, Claudio; Motta, Antonella

2012-12-03

140

In vitro study on silk fibroin textile structure for Anterior Cruciate Ligament regeneration.  

Science.gov (United States)

A novel hierarchical textile structure made of silk fibroin from Bombyx mori capable of matching the mechanical performance requirements of anterior cruciate ligament (ACL) and in vitro cell ingrowth is described. This sericin-free, Silk Fibroin Knitted Sheath with Braided Core (SF-KSBC) structure was fabricated using available textile technologies. Micro-CT analysis confirmed that the core was highly porous and had a higher degree of interconnectivity than that observed for the sheath. The in vivo cell colonization of the scaffolds is thus expected to penetrate even the internal parts of the structure. Tensile mechanical tests demonstrated a maximum load of 1212.4±56.4N (under hydrated conditions), confirming the scaffold's suitability for ACL reconstruction. The absence of cytotoxic substances in the extracts of the SF-KSBC structure in culture medium was verified by in vitro tests with L929 fibroblasts. In terms of extracellular matrix production, Human Periodontal Ligament Fibroblasts (HPdLFs) cultured in direct contact with SF-KSBC, compared to control samples, demonstrated an increased secretion of aggrecan (PG) and fibronectin (FBN) at 3 and 7days of culture, and no change in IL-6 and TNF-? secretion. Altogether, the outcomes of this investigation confirm the significant utility of this novel scaffold for ACL tissue regeneration. PMID:23910255

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

2013-04-20

 
 
 
 
141

Bio-inspired capillary dry spinning of regenerated silk fibroin aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

To biomimic the spinning process of silkworm or spider, a capillary spinning equipment was applied to spin regenerated silk fibroin (RSF) fibers from RSF aqueous solutions in air. This equipment exhibits a wide processing window for various RSF aqueous solutions. The effects of pH, metal ions, RSF concentration and spinning parameters on the spinnability of the spinning dope and the mechanical properties of the obtained fibers were investigated. As a result, spinning dopes with a pH from 5.2 to 6.9 have good spinnability, especially for the dope with a pH of 6.0 and a Ca{sup 2+} concentration of 0.3 M. The RSF concentration of this dope ranges from 44% to 48%. Under optimized conditions of our dry spinning experiments (L/D, 133; take-up speed, 30 mm/s), the obtained as-spun fiber has a breaking strength of 46 MPa, which can be improved up to 359 MPa after a preliminary post-drawing in 80 vol.% ethanol aqueous solution. Highlights: {yields} Regenerated silk fibroin fibers were prepared by using a dry spinning method. {yields} Dope compositions affect dope spinnability. {yields} Spinning parameters affect dope spinnability and fiber properties. {yields} The breaking stress of the post-treated fiber was up to 359 MPa.

Wei Wei; Zhang Yaopeng, E-mail: zyp@dhu.edu.cn; Zhao Yingmei; Luo Jie; Shao Huili; Hu Xuechao

2011-10-10

142

High-affinity integration of hydroxyapatite nanoparticles with chemically modified silk fibroin  

Energy Technology Data Exchange (ETDEWEB)

Hydroxyapatite (HA)-based nanocomposites were prepared by a co-precipitation method with silk fibroin (SF) serving as organic matrix. Silk fibroin was chemically modified with an alkali solution or an enzyme attempting to improve the interface between the mineral and the organic matrix. The influences of the alkali and enzyme pretreatments on microstructure and physicochemical properties of HA-SF composite were examined and compared. The results reveal that both the two kinds of pretreatments facilitate the formation of highly ordered three-dimensional porous network throughout the composites, increase the microhardness of the composite, and promote the preferential growth of HA crystallites along c-axis. Among all the as-prepared samples, the composite containing the enzyme pretreated SF shows desirable hierarchical microstructure with higher degree of organization and more uniform pore size distribution. Due to the enzyme pretreatment, HA crystallites undergo obvious changes in morphology from rod-like to whisker-like and in crystal growth towards more apparent epitaxy along c-axis. The alkali pretreatment induces the stronger chemical interactions between HA and SF and thus to strengthen the inorganic-organic interfacial adhesion. The newly developed HA-SF composites are expected to be attractive biomedical materials for bone repair and remodeling.

Wang Li; Li Chunzhong [East China University of Science and Technology, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China)], E-mail: czli@ecust.edu.cn; Senna, Mamoru [Keio University, Department of Applied Chemistry, Faculty of Science and Technology (Japan)

2007-10-15

143

Preparation and properties of nanometer silk fibroin peptide/polyvinyl alcohol blend films for cell growth.  

UK PubMed Central (United Kingdom)

Nanometer silk fibroin peptide (Nano-SFP) was prepared from silkworm cocoons through the process of dissolution, dialysis and enzymolysis. For comparison, silk fibroin was decomposed with ?-chymotrypsin, trypsin and neutrase, respectively. From the SEM and particle size analysis results, the Nano-SFP prepared by neutrase was found to be the most desirable at about 50-200nm. Nano-SFP/polyvinyl alcohol films (Nano-SFP/PVA) were prepared by blending Nano-SFP and PVA in water with different weight ratios of 10/90, 20/80, 30/70, and 40/60. The films were characterized by IR, SEM, TG, DSC and tensile strength test for investigating their structure, surface morphology, thermostability, and mechanical property. The results showed that Nano-SFP inserted in the PVA films with small linear particles, and Nano-SFP/PVA films exhibited smooth surface, good thermostability and tensile strength. The growth of Chinese hamster ovary (CHO) cells on films with and without Nano-SFP was investigated with MTT colorimetric assay to assess the films' ability to promote cell growth. It was observed that the Nano-SFP improved cell adhesion on the film surface, and the ability of promoting cell growth increased with the increasing content of Nano-SFP in the blend films. Nano-SFP/PVA film with the ratio of 30/70 was concluded to have the best properties.

Luo Q; Chen Z; Hao X; Zhu Q; Zhou Y

2013-10-01

144

Study on Preparation of n-HA and Silk Fibroin Bio-mineral Material  

Directory of Open Access Journals (Sweden)

Full Text Available A new hydroxyapatite (n-HA)ª²Silk fibroin (SF) bio-mineral material was prepared by using a biomimetic method, with Ca(NO3)2 and Na3PO4 used as the starting reagent to synthesize the inorganic phase. In details, SF was dissolved in Ca(NO3)2 solution without desalting procedure, the compound solution was directly dropped into Na3PO4 solution. In this way, HA was synthesized at 37¡?y controlling Ca/P ratio, meanwhile the minerialized HA interacted with SF to form biomineral material. The morphology and structure of this n-HA-SF biomineral material were characterized by XRD, FTIR, XPS and SEM. The results show that there are strong chemical interaction between n-HA and SF. Moreover, in the biomineral material, the inorganic phase is calciumª²deficient hydroxyapatite, containing a small amount of carbonated HA with an average crystal size of 37.6nm. In addition, The particle size of biomineral materials range from 50nm to 200nm.It can be deduced that silk fibroin chain can regulate the growth and morphology of HA crystals. The compressive strength of the biomineral material is 32.21MPa£¬ which is a good potential material for bone tissue engineering and unloadedª²bearing bone defects repairing.

WANG Jiang,ZUO Yi,YANG Wei-Hu,ZHOU Gang,ZHANG Li,LI Yu-Bao

2009-01-01

145

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

UK PubMed Central (United Kingdom)

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

Farè S; Torricelli P; Giavaresi G; Bertoldi S; Alessandrino A; Villa T; Fini M; Tanzi MC; Freddi G

2013-10-01

146

Tissue-engineered mesh for pelvic floor reconstruction fabricated from silk fibroin scaffold with adipose-derived mesenchymal stem cells.  

UK PubMed Central (United Kingdom)

A tissue-engineered mesh fabricated with adipose-derived mesenchymal stem cells (AD-MSCs) cultured on a silk fibroin scaffold is evaluated for use in female pelvic reconstruction. Thirty-five female Sprague Dawley rats were divided into four groups. Group A (n?=?10) were implanted with polypropylene meshes, Group B (n?=?10) with silk fibroin scaffolds and Group C (n?=?10) with tissue-engineered meshes. Group D (n?=?5) acted as the tissue control. The tissue-engineered mesh was produced as follows. AD-MSCs were obtained from adipose tissue of rats designated to Group C. The cells were seeded onto a silk fibroin scaffold, cultured and then observed by scanning electron microscopy (SEM). Histological studies of these meshes were performed at 4 and 12 weeks after implantation and mechanical testing was carried out on all groups before implantation and at 12 weeks after implantation. AD-MSCs displayed fibroblast-like shapes and were able to differentiate into adipocytes or fibroblasts. SEM observation showed that AD-MSCs proliferated and secreted a matrix onto the silk fibroin scaffolds. After implantation of the scaffolds into rats, histological analysis revealed better organized newly formed tissue in Group C than in controls. Group C also had a similar failure force (2.67?±?0.15 vs 2.33?±?0.38 N) and a higher Young's modulus (2.99?±?0.19 vs 1.68?±?0.20 MPa) than a normal vaginal wall, indicating the potential of this tissue-engineered approach. AD-MSCs were validated as seed cells for tissue engineering. The silk fibroin scaffold thus shows promise for application with AD-MSCs in the fabrication of tissue-engineered mesh with good biocompatibility and appropriate mechanical properties for pelvic floor reconstruction.

Li Q; Wang J; Liu H; Xie B; Wei L

2013-08-01

147

Tissue-engineered mesh for pelvic floor reconstruction fabricated from silk fibroin scaffold with adipose-derived mesenchymal stem cells.  

Science.gov (United States)

A tissue-engineered mesh fabricated with adipose-derived mesenchymal stem cells (AD-MSCs) cultured on a silk fibroin scaffold is evaluated for use in female pelvic reconstruction. Thirty-five female Sprague Dawley rats were divided into four groups. Group A (n?=?10) were implanted with polypropylene meshes, Group B (n?=?10) with silk fibroin scaffolds and Group C (n?=?10) with tissue-engineered meshes. Group D (n?=?5) acted as the tissue control. The tissue-engineered mesh was produced as follows. AD-MSCs were obtained from adipose tissue of rats designated to Group C. The cells were seeded onto a silk fibroin scaffold, cultured and then observed by scanning electron microscopy (SEM). Histological studies of these meshes were performed at 4 and 12 weeks after implantation and mechanical testing was carried out on all groups before implantation and at 12 weeks after implantation. AD-MSCs displayed fibroblast-like shapes and were able to differentiate into adipocytes or fibroblasts. SEM observation showed that AD-MSCs proliferated and secreted a matrix onto the silk fibroin scaffolds. After implantation of the scaffolds into rats, histological analysis revealed better organized newly formed tissue in Group C than in controls. Group C also had a similar failure force (2.67?±?0.15 vs 2.33?±?0.38 N) and a higher Young's modulus (2.99?±?0.19 vs 1.68?±?0.20 MPa) than a normal vaginal wall, indicating the potential of this tissue-engineered approach. AD-MSCs were validated as seed cells for tissue engineering. The silk fibroin scaffold thus shows promise for application with AD-MSCs in the fabrication of tissue-engineered mesh with good biocompatibility and appropriate mechanical properties for pelvic floor reconstruction. PMID:23996203

Li, Qi; Wang, Jianliu; Liu, Haifeng; Xie, Bing; Wei, Lihui

2013-08-31

148

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-03-15

149

Fabrication and characterization of novel diopside/silk fibroin nanocomposite scaffolds for potential application in maxillofacial bone regeneration.  

UK PubMed Central (United Kingdom)

Novel freeze-dried porous composite scaffolds were prepared from natural polymer of silk fibroin (SF) as a matrix and from diopside nanoceramic as a bioactive reinforcing agent through a freeze-drying method. Considering the superiority of both diopside and SF in terms of mechanical and biochemical properties (in comparison to similar ceramics and polymers, especially in maxillofacial specific applications), we investigated the effect of diopside nanoparticle contents. Microstructure studies illustrated that the bioactive diopside nanoparticles were distributed throughout the fibroin matrix. Enough porosity, desired surface properties, high mechanical strength and excellent in vitro biocompatibility were achieved during the fabrication of the nanocomposite scaffolds without any extra modifications.

Ghorbanian L; Emadi R; Razavi SM; Shin H; Teimouri A

2013-07-01

150

Preparation of Eri silk fibroin and gelatin blend film loaded chlorhexidine using as model for hydrophilic drug release  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this research was to prepare Eri silk fibroin solution for preparing silk film loaded chlorhexidine drug as model for hydrophilic drug release. The Eri silk cocoons were boiled in 0.5%NaCO3 solution at 90?, and then left in air dried at room temperature. The fibroin was dissolved in 9M (Ca(NO3)2) with ethanol (2 by mole) and heated at 70?. The silk fibroin (SF) solution was then dialyzed to exclude salt in phosphate buffer. The SF and gelatin (G) solutions were mixed for preparation of films in both with and without chlorhexidine. The films were observed their morphology under scanning electron microscope. The results found that all of films were rough of their surfaces, homogeneous texture without phase separation. The native SF film composed of pores throughout the film area but did not observe in native G film. The results also showed that the SF and G can be good interacted to form hydrogen bonds. These were indicated from FTIR spectra and thermal analysis. The chlorhexidine drug has not affect on the changes of film properties. However, the releasing pattern of chlorhexidine from each film was varied. The highest rate of drug releasing was found in the native SF film while the native G film was the lowest. It might be suggested that the drug releasing rate was depended on polarity of each polymer components.

Yaowalak Srisuwan; Nualchai Kotseang; Komsan Namtaku; Wilaiwan Simchuer; Chirapha Butiman; Prasong Srihanam

2012-01-01

151

Preparation of chitosan/silk fibroin blending membrane fixed with alginate dialdehyde for wound dressing.  

UK PubMed Central (United Kingdom)

The objective of this work was to prepare chitosan/silk fibroin (CS/SF) blending membranes crosslinked with alginate dialdehyde (ADA) as wound dressings and to evaluate the physical properties and biocompatibility of the membranes. The morphology of membrane was observed by scanning electron microscopy (SEM) which showed that the well consistency of these two compositions. Further, the stability, water absorption and water vapor permeability of the ADA fixed CS/SF membranes could meet the needs of wound dressing. Furthermore, the biocompatibility of ADA fixed membranes was investigated by MTT assays and SEM in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that ADA fixed CS/SF blending membranes with a suitable ratio could be a promising candidate for wound healing applications.

Gu Z; Xie H; Huang C; Li L; Yu X

2013-07-01

152

Patterning and photoluminescence of CdS nanocrystallites on silk fibroin fiber  

International Nuclear Information System (INIS)

[en] CdS nanocrystallites could be formed and assembled into nanoparticle strings and hexagons on natural silk fibroin fiber (SFF) through a room-temperature bio-inspired process. Herein, the biomaterial SFF served as reactive substrate, not only provides the in situ formation sites for CdS nanocrystallites, but also directs the arrangement of nanocrystalline CdS simultaneously. The photoluminescence (PL) of the resulting nanocomposites CdS/SFF is investigated extensively. The PL peaks observed from CdS nanoparticle strings are similar to those of separate CdS nanoparticles, corresponding to the band-edge emission of their individual building blocks (QD-CdS). Moreover, CdS nanoparticle hexagons perform a red-shifted and broadened emission peak.

2010-01-01

153

The application with protocatechualdehyde to improve anticoagulant activity and cell affinity of silk fibroin  

International Nuclear Information System (INIS)

Protocatechualdehyde (PCA) is one of the effective ingredients extracted from Danshen (Radix Salviae Miltiorrhizae) and was employed to modify the silk fibroin (SF) by graft polymerization and surface adsorption. The surface composition of modified SF was characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and UV spectrophotometer. The anticoagulant activity of modified SF was assessed by in vitro coagulation test and platelet adhesion measurement. The endothelial cell affinity was evaluated by a parallel plate flow chamber. The test results indicated that with the introduction of PCA into SF, the anticoagulant activity has been improved obviously. And the SF surface composition altered by PCA, but did not disturb its ?-sheet conformation. Moreover, the adsorbed PCA on SF surface can enhance the endothelial cell affinity

1000-01-00

154

Effect of Methanol Treatment on Regenerated Silk Fibroin Microparticles Prepared by the Emulsification-Diffusion Technique  

Directory of Open Access Journals (Sweden)

Full Text Available 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 determined from FTIR spectra changed from predominantly random coil to ?-sheet form after methanol treatment. Particle surfaces of methanol-treated SF microparticles were rougher than those of non-treated. The SF concentrations and methanol treatment did not affect open hollow structure of the SF microparticles. Major advantages of this method are the elimination of surfactants and extractable pore templates. These hollow SF microparticles are expected to be potential used as biodegradable microcarriers of cell and protein drug, because their hollow structures should permit cell attachment and enzyme immobilization.

Yodthong Baimark; Prasong Srihanam

2009-01-01

155

The application with protocatechualdehyde to improve anticoagulant activity and cell affinity of silk fibroin  

Energy Technology Data Exchange (ETDEWEB)

Protocatechualdehyde (PCA) is one of the effective ingredients extracted from Danshen (Radix Salviae Miltiorrhizae) and was employed to modify the silk fibroin (SF) by graft polymerization and surface adsorption. The surface composition of modified SF was characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and UV spectrophotometer. The anticoagulant activity of modified SF was assessed by in vitro coagulation test and platelet adhesion measurement. The endothelial cell affinity was evaluated by a parallel plate flow chamber. The test results indicated that with the introduction of PCA into SF, the anticoagulant activity has been improved obviously. And the SF surface composition altered by PCA, but did not disturb its {beta}-sheet conformation. Moreover, the adsorbed PCA on SF surface can enhance the endothelial cell affinity.

Wang Song [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)], E-mail: wangsongbit@126.com; Gao Zhen; Li Erlin; Su Caoning; Zhu Hesun [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2008-11-15

156

Evaluation of electronspun silk fibroin-based transplants used for facial nerve repair.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To study whether regenerated electrospun silk fibroin (SF) nanofibers as nerve conduits could improve nerve regeneration microenvironment and induce the facial nerve regeneration of Sprague-Dawley rats. DESIGN: Electrospun SF nanofibers were prepared to bridge a 5-mm facial nerve defect in Sprague-Dawley rats. Three months after implantation, a comprehensive morphologic and functional evaluation was performed by electrophysiology, histology, Fluorogold retrograde tracing, and transmission electron micrograph. RESULTS: The SF nanofiber tube exhibited good biocompatibility in vivo, and no distinct regional inflammation response and scar formation was observed. After 3 months of operation, the morphologic and functional investigation has shown a positive evaluation on the nerve repair outcome elicited by SF nanofiber graft and autograft. CONCLUSION: Electrospun SF grafts could promote nerve regeneration after facial nerve injury and become a potential possibility of newly developed nerve grafts as an alternative of autografts to peripheral nerve regeneration.

Hu A; Zuo B; Zhang F; Zhang H; Lan Q

2013-02-01

157

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

UK PubMed Central (United Kingdom)

Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 ± 16 MPa and a failure strain of 1.8 ± 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 ± 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets.

Huang L; Li C; Yuan W; Shi G

2013-05-01

158

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

Directory of Open Access Journals (Sweden)

Full Text Available A novel bone-like biomaterial of hydroxyapatite (HAP) and silk fibroin (SF) composite was developed by biomimetic synthesis. The composite was precipitated from drops of Ca(OH)2 suspension and H3PO4 solution with SF. With this method, the HAP nanocrystals were obtained by self-assembling on a SF surface whose c-axis was aligned with the long-axis direction of SF in microstructures; this shares the same misconstrues of collagen and HAP with that in the natural bone. The HAP/SF composite then demonstrated that it could promote osteoblast proliferation in vitro and new bone formation in vivo. The novel biomaterial is a promising material for bone replacement and regeneration.

Lin Niu; Rui Zou; Qida Liu; Quanli Li; Xinmin Chen; Zhiqing Chen

2010-01-01

159

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

Energy Technology Data Exchange (ETDEWEB)

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

Nemoto, Rei; Wang Li [Keio University, Department of Applied Chemistry, Faculty of Science and Technology (Japan); Ikoma, Toshiyuki; Tanaka, Junzo [National Institute for Materials Science (NIMS) (Japan); Senna, Mamoru [Keio University, Department of Applied Chemistry, Faculty of Science and Technology (Japan)], E-mail: senna@applc.keio.ac.jp

2004-06-15

160

Preparation and Characterization of Insoluble Silk Fibroin/Chitosan Blend Films  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to prepare and characterize membranes of silk fibroin (SF) and chitosan (CHI) blends. Moreover, a conformation transition of SF to a more stable form induced by the addition of CHI was verified. Blend membranes were prepared, after pH adjustment, in different ratios, and physical integrity, crystallinity, structural conformation and thermal stability were characterized. The results of crystallographic analysis (XRD) indicated the tendency to higher structural organization caused by the addition of CHI. Fourier transformed infrared spectroscopy (FTIR) showed that SF is present in a more stable form in the presence of a CHI content of only 25 wt%. Thermal analysis indicated that SF is thermally stable and that when its proportion in the blend increases, the temperature at which degradation is initiated also increases.

Mariana Agostini de Moraes; Grinia Michelle Nogueira; Raquel Farias Weska; Marisa Masumi Beppu

2010-01-01

 
 
 
 
161

Conformation Transition and Thermal Properties Study of Silk Fibroin and Poly (?-Caprolactone) Blends  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, influence of intermolecular interactions between Silk Fibroin (SF) and Poly (?-Caprolactone) (PCL) in homogeneous blend form on SF conformation changes and thermal properties of the blends was investigated and discussed. The SF/PCL blends were prepared by solution blending and precipitating method, respectively. Dimethylsulfoxide and isopropanol were used as a solvent and a non-solvent, respectively. The blends were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermo Gravimetry (TG) and Scanning Electron Microscopy (SEM). Conformation transition of SF component from ?-sheet to random coil forms can be induced by blending with PCL. Melting temperature and heat of melting of the PCL decreased as increasing the SF ratio. Thermal stability of the SF can be enhanced by blending with PCL. FTIR, DSC and TG results suggested that intermolecular hydrogen bonds were formed between SF and PCL molecules in the blends. Homogeneous morphology of blends was illustrated by SEM micrographs.

M. Srisa-Ard; Y. Baimark; Y. Srisuwan

2008-01-01

162

Patterning and photoluminescence of CdS nanocrystallites on silk fibroin fiber  

Energy Technology Data Exchange (ETDEWEB)

CdS nanocrystallites could be formed and assembled into nanoparticle strings and hexagons on natural silk fibroin fiber (SFF) through a room-temperature bio-inspired process. Herein, the biomaterial SFF served as reactive substrate, not only provides the in situ formation sites for CdS nanocrystallites, but also directs the arrangement of nanocrystalline CdS simultaneously. The photoluminescence (PL) of the resulting nanocomposites CdS/SFF is investigated extensively. The PL peaks observed from CdS nanoparticle strings are similar to those of separate CdS nanoparticles, corresponding to the band-edge emission of their individual building blocks (QD-CdS). Moreover, CdS nanoparticle hexagons perform a red-shifted and broadened emission peak.

Han Jie; Su Huilan, E-mail: hlsu@sjtu.edu.cn; Dong Qun; Zhang Di, E-mail: zhangdi@sjtu.edu.cn; Ma Xiaoxiao [Shanghai Jiaotong University, State Key Laboratory of Metal Matrix Composites (China); Zhang Chunfu [Shanghai Jiaotong University, Med-X Research Institute (China)

2010-01-15

163

Silk Fibroin/Gelatin Blend Films Crosslinked with Enzymes for Biomedical Applications.  

UK PubMed Central (United Kingdom)

Microbial transglutaminase (mTG) and mushroom tyrosinase (MT) are used to crosslink B. mori silk fibroin/gelatin (SF/G) films. Crosslinked and uncrosslinked SF/G films show no phase separation. The thermal behavior and the conformational structure of SF/G films are strongly affected by blending and enzymatic treatment. Formation of high thermally stable crosslinked macromolecular species is observed, suggesting the occurrence of strong intermolecular interactions between the two polymers as confirmed by FT-Raman spectroscopy. Preliminary in vitro tests show that MT-crosslinked blends with G amounts ?40% and mTG-crosslinked SF/G 60/40 films support C2C12 cardiomyocyte adhesion and proliferation.

Taddei P; Chiono V; Anghileri A; Vozzi G; Freddi G; Ciardelli G

2013-08-01

164

Fabrication and characterization of silk fibroin-derived curcumin nanoparticles for cancer therapy  

Directory of Open Access Journals (Sweden)

Full Text Available Vishal Gupta1, Abraham Aseh1,3, Carmen N Ríos1, Bharat B Aggarwal2, Anshu B Mathur11Department of Plastic Surgery; 2Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA; 3School of Pharmacy, Texas Southern University, Houston, TX, USAAbstract: Biologically derived nanoparticles (<100 nm) were fabricated for local and sustained therapeutic curcumin delivery to cancer cells. Silk fibroin (SF) and chitosan (CS) polymers were blended noncovalently to encapsulate curcumin in various proportions of SF and CS (75:25, 50:50, and 25:75 SF:CS) or pure SF at two concentrations (0.1% w/v and 10% w/v) using the devised capillary-microdot technique. Curcumin-polymer conjugates were frozen, lyophilized, crystallized, suspended in phosphate-buffered saline for characterization, and tested for efficacy against breast cancer cells. All nanoparticle formulations except 0.1% w/v 50:50 SFCS were less than 100 nm in size as determined with the transmission electron microscopy. The entrapment and release of curcumin over eight days was highest for SF-derived nanoparticles as compared to all SFCS blends. The uptake and efficacy of SF-coated curcumin was significantly higher (p < 0.001) than SFCS-coated curcumin in both low and high Her2/neu expressing breast cancer cells. Interestingly, the uptake of curcumin was highest for the high Her2/neu expressing breast cancer cells when delivered with a 10% w/v SF coating as compared to other formulations. In conclusion, SF-derived curcumin nanoparticles show higher efficacy against breast cancer cells and have the potential to treat in vivo breast tumors by local, sustained, and long-term therapeutic delivery as a biodegradable system.Keywords: biodegradable, nanoparticles, curcumin, silk fibroin, breast cancer cells

Vishal Gupta; Abraham Aseh; Carmen N Ríos; Bharat B Aggarwal; et al.

2009-01-01

165

In situ synthesis and photoluminescence of QD-CdS on silk fibroin fibers at room temperature  

Energy Technology Data Exchange (ETDEWEB)

A convenient room-temperature bioinspired technique has been developed to synthesize hybrid nanocomposites consisting of well-dispersed CdS quantum dots (QD) and the substrate silk fibroin fibers (SFF). The biomaterial SFF provides both a supporting substrate and functional sites for the in situ generation of QD-CdS, which is supported by FTIR and PL measurements. The solid QD-CdS/SFF nanocomposites could be useful in photocatalyst, novel luminescence and photoelectron transfer devices. The QD-CdS/silk fibroin (SF) colloid, in which SF acts as both an inherent biocompatibilizer and an efficient passivator of trap sites on the QD-CdS surface, is also available for some potential applications in the biological fields. The bioinspired method and relevant ideas could extend to fabricating other functional hybrid materials.

Su Huilan [State Key Lab of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai 200030 (China); Han Jie [State Key Lab of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai 200030 (China); Dong Qun [State Key Lab of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai 200030 (China); Zhang Di [State Key Lab of Metal Matrix Composites, Shanghai Jiaotong University, Shanghai 200030 (China); Guo Qixin [Department of Electrical and Electronic Engineering, Saga University, Saga 840-8502 (Japan)

2008-01-16

166

Immunosensor based on immobilization of antigenic peptide NS5A-1 from HCV and silk fibroin in nanostructured films.  

UK PubMed Central (United Kingdom)

The peptide NS5A-1 (PPLLESWKDPDYVPPWHG), derived from hepatitis C virus (HCV) NS5A protein, was immobilized into layer-by-layer (LbL) silk fibroin (SF) films. Deposition was monitored by UV-vis absorption measurements at each bilayer deposited. The interaction SF/peptide film induced secondary structure in NS5A-1 as indicated by fluorescence and circular dichroism (CD) measurements. Voltammetric sensor (SF/NS5A-1) properties were observed when the composite film was tested in the presence of anti-HCV. The peptide-silk fibroin interaction studied here showed new architectures for immunosensors based on antigenic peptides and SF as a suitable immobilization matrix.

Moraes ML; Lima LR; Silva RR; Cavicchioli M; Ribeiro SJ

2013-03-01

167

Hydroxyapatite/regenerated silk fibroin scaffold-enhanced osteoinductivity and osteoconductivity of bone marrow-derived mesenchymal stromal cells.  

UK PubMed Central (United Kingdom)

A novel hydroxyapatite/regenerated silk fibroin scaffold was prepared and investigated for its potential to enhance both osteoinductivity and osteoconductivity of bone marrow-derived mesenchymal stromal cells in vitro. Approx. 12.4 ± 0.06 % (w/w) hydroxyapatite was deposited onto the scaffold, and cell viability and DNA content were significantly increased (18.5 ± 0.6 and 33 ± 1.2 %, respectively) compared with the hydroxyapatite scaffold after 14 days. Furthermore, alkaline phosphatase activity in the novel scaffold increased 41 ± 2.5 % after 14 days compared with the hydroxyapatite scaffold. The data indicate that this novel hydroxyapatite/regenerated silk fibroin scaffold has a positive effect on osteoinductivity and osteoconductivity, and may be useful for bone tissue engineering.

Jiang J; Hao W; Li Y; Yao J; Shao Z; Li H; Yang J; Chen S

2013-04-01

168

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

International Nuclear Information System (INIS)

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.

2006-01-01

169

Effects of silk fibroin fiber incorporation on mechanical properties, endothelial cell colonization and vascularization of PDLLA scaffolds.  

Science.gov (United States)

Attainment of functional vascularization of engineered constructs is one of the fundamental challenges of tissue engineering. However, the development of an extracellular matrix in most tissues, including bone, is dependent upon the establishment of a well developed vascular supply. In this study a poly(d,l-lactic acid) (PDLLA) salt-leached sponge was modified by incorporation of silk fibroin fibers to create a multicomponent scaffold, in an effort to better support endothelial cell colonization and to promote in vivo vascularization. Scaffolds with and without silk fibroin fibers were compared for microstructure, mechanical properties, ability to maintain cell populations in vitro as well as to permit vascular ingrowth into acellular constructs in vivo. We demonstrated that adding silk fibroin fibers to a PDLLA salt-leached sponge enhanced scaffold properties and heightened its capacity to support endothelial cells in vitro and to promote vascularization in vivo. Therefore refinement of scaffold properties by inclusion of materials with beneficial attributes may promote and shape cellular responses. PMID:23522374

Stoppato, Matteo; Stevens, Hazel Y; Carletti, Eleonora; Migliaresi, Claudio; Motta, Antonella; Guldberg, Robert E

2013-03-19

170

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

171

Effects of silk fibroin fiber incorporation on mechanical properties, endothelial cell colonization and vascularization of PDLLA scaffolds.  

UK PubMed Central (United Kingdom)

Attainment of functional vascularization of engineered constructs is one of the fundamental challenges of tissue engineering. However, the development of an extracellular matrix in most tissues, including bone, is dependent upon the establishment of a well developed vascular supply. In this study a poly(d,l-lactic acid) (PDLLA) salt-leached sponge was modified by incorporation of silk fibroin fibers to create a multicomponent scaffold, in an effort to better support endothelial cell colonization and to promote in vivo vascularization. Scaffolds with and without silk fibroin fibers were compared for microstructure, mechanical properties, ability to maintain cell populations in vitro as well as to permit vascular ingrowth into acellular constructs in vivo. We demonstrated that adding silk fibroin fibers to a PDLLA salt-leached sponge enhanced scaffold properties and heightened its capacity to support endothelial cells in vitro and to promote vascularization in vivo. Therefore refinement of scaffold properties by inclusion of materials with beneficial attributes may promote and shape cellular responses.

Stoppato M; Stevens HY; Carletti E; Migliaresi C; Motta A; Guldberg RE

2013-06-01

172

An emerging functional natural silk biomaterial from the only domesticated non-mulberry silkworm Samia ricini.  

UK PubMed Central (United Kingdom)

Mulberry silk fibroin is a widely used biomaterial and recent work on non-mulberry silk fibroin also suggests it may have similar uses. We expect silk fibroin from the only domesticated non-mulberry eri silkworm, Samia ricini, to possess useful properties as a biomaterial. Eri silk gland fibroin is a heterodimeric protein of approximately 450?kDa. Cytocompatibility evaluation with fibroblasts and osteoblast-like cells shows good cell attachment, viability and proliferation. The matrices, which have high thermal stability and good swellability, are also haemocompatible. Eri silk production is cost effective as no agronomic practices are required for their host plant cultivation. This fibroin provide new opportunities as an alternative natural functional biomaterial in various biomedical applications.

Pal S; Kundu J; Talukdar S; Thomas T; Kundu SC

2013-08-01

173

Formulation and characterization of silk fibroin films as a scaffold for adipose-derived stem cells in skin tissue engineering.  

UK PubMed Central (United Kingdom)

Skin substitutes are epidermal, dermal or complete bilayered constructs, composed by natural or synthetic scaffolds and by adherent cells such as fibroblasts, keratinocytes or mesenchymal stem cells. Silk fibroin is a promising polymer to realize scaffolds, since it is biocompatible, biodegradable, and exhibits excellent mechanical properties in terms of tensile strength. Moreover, fibroin can be added of others components in order to modify the biomaterial properties for the purpose. The aim of this work is to prepare silk fibroin films for adipose-derived stem cell (ADSCs) culture as a novel feeder layer for skin tissue engineering. Pectin has been added to promote the protein conformational transition and construct strength, while glycerol as plasticizer, providing biomaterial flexibility. Eighteen formulations were prepared by casting method using fibroin, pectin (range 1-10% w/w), and glycerol (range 0-20% w/w); films were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry assay, to select the optimal composition. A stable fibroin conformation was obtained using 6% w/w pectin, and the best mechanical properties were obtained using 12% w/w glycerol. Films were sterilized, and human ADSCs were seeded and cultured for 15 days. Cells adhere to the support assuming a fibroblastic-like shape and reaching confluence. The ultrastructural analysis evidences typical active-cell features and adhesion structures that promote cell anchorage to the film, thus developing a multilayered cell structure. This construct could be advantageously employed in cutaneous wound healing or where the use of ADSCs scaffold is indicated either in human or veterinary field.

Chlapanidas T; Tosca MC; Faragò S; Perteghella S; Galuzzi M; Lucconi G; Antonioli B; Ciancio F; Rapisarda V; Vigo D; Marazzi M; Faustini M; Torre ML

2013-01-01

174

Shear-induced rigidity in spider silk glands  

Science.gov (United States)

We measure the elastic stiffnesses of the concentrated viscous protein solution of the dehydrated Nephila clavipes major ampullate gland with Brillouin light scattering. The glandular material shows no rigidity but possesses a tensile stiffness similar to that of spider silk. We show, however, that with application of a simple static shear, the mechanical properties of the spider gland protein mixture can be altered irreversibly, lowering symmetry and enabling shear waves to be supported, thus, giving rise to rigidity and yielding elastic properties similar to those of the naturally spun (i.e., dynamically sheared) silk.

Koski, Kristie J.; McKiernan, Keri; Akhenblit, Paul; Yarger, Jeffery L.

2012-09-01

175

Preparation and characterization of blends containing silk fibroin and chitosan;Obtencao e caracterizacao de blendas de fibroina de seda e quitosana  

Energy Technology Data Exchange (ETDEWEB)

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)

Moraes, Mariana A. de; Nogueira, Grinia M.; Weska, Raquel F.; Beppu, Marisa M., E-mail: beppu@feq.unicamp.b [Universidade Estadual de Campinas (FEQ/UNICAMP), SP (Brazil). Faculdade de Engenharia Quimica

2009-07-01

176

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

International Nuclear Information System (INIS)

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

2012-08-01

177

Effect of sterilization on structural and material properties of 3D silk fibroin scaffolds.  

UK PubMed Central (United Kingdom)

The development of porous scaffolds for tissue engineering applications requires careful choice of properties as these influence cell adhesion, proliferation and differentiation. Sterilization of scaffolds is a prerequisite for in vitro culture as well as for subsequent in vivo implantation. The variety of methods to provide sterility is as diverse as the possible effects they can have on structural and material properties of the 3D porous structure, especially in polymeric or proteinous scaffold materials. Silk fibroin (SF) has previously been demonstrated to offer exceptional benefits over conventional synthetic and natural biomaterials in generating scaffolds for tissue replacements. This study sought to determine the effect of sterilization methods, such as autoclaving, heat-, ethylene oxide-, ethanol- or antibiotic-antimycotic treatment on porous 3D SF scaffolds. In terms of scaffold morphology, topography, crystallinity and short-term cell viability the different sterilization methods showed only few effects. Nevertheless, mechanical properties were significantly decreased by a factor of two by all methods except for dry autoclaving, which seemed not to affect mechanical properties compared to the native control group. These data suggest that SF scaffolds are in general highly resistant to various sterilization treatments. Nevertheless, care should be taken if initial mechanical properties are of interest.

Hofmann S; Stok KS; Kohler T; Meinel AJ; Müller R

2013-09-01

178

The cultivation of human retinal pigment epithelial cells on Bombyx mori silk fibroin.  

Science.gov (United States)

We have presently evaluated membranes prepared from Bombyx mori silk fibroin (BMSF), for their potential use as a prosthetic Bruch's membrane and carrier substrate for human retinal pigment epithelial (RPE) cell transplantation. Porous BMSF membranes measuring 3 ?m in thickness were prepared from aqueous solutions (3% w/v) containing poly(ethylene oxide) (0.09%). The permeability coefficient for membranes was between 3 and 9 × 10(-5) cm/s by using Allura red or 70 kDa FITC-dextran respectively. Average pore size (±sd) was 4.9 ± 2.3 ?m and 2.9 ± 1.5 ?m for upper and lower membrane surfaces respectively. Optimal attachment of ARPE-19 cells to BMSF membrane was achieved by pre-coating with vitronectin (1 ?g/mL). ARPE-19 cultures maintained in low serum on BMSF membranes for approximately 8 weeks, developed a cobble-stoned morphology accompanied by a cortical distribution of F-actin and ZO-1. Similar results were obtained using primary cultures of human RPE cells, but cultures took noticeably longer to establish on BMSF compared with tissue culture plastic. These findings encourage further studies of BMSF as a substrate for RPE cell transplantation. PMID:22406408

Shadforth, Audra M A; George, Karina A; Kwan, Anthony S; Chirila, Traian V; Harkin, Damien G

2012-03-09

179

The cultivation of human retinal pigment epithelial cells on Bombyx mori silk fibroin.  

UK PubMed Central (United Kingdom)

We have presently evaluated membranes prepared from Bombyx mori silk fibroin (BMSF), for their potential use as a prosthetic Bruch's membrane and carrier substrate for human retinal pigment epithelial (RPE) cell transplantation. Porous BMSF membranes measuring 3 ?m in thickness were prepared from aqueous solutions (3% w/v) containing poly(ethylene oxide) (0.09%). The permeability coefficient for membranes was between 3 and 9 × 10(-5) cm/s by using Allura red or 70 kDa FITC-dextran respectively. Average pore size (±sd) was 4.9 ± 2.3 ?m and 2.9 ± 1.5 ?m for upper and lower membrane surfaces respectively. Optimal attachment of ARPE-19 cells to BMSF membrane was achieved by pre-coating with vitronectin (1 ?g/mL). ARPE-19 cultures maintained in low serum on BMSF membranes for approximately 8 weeks, developed a cobble-stoned morphology accompanied by a cortical distribution of F-actin and ZO-1. Similar results were obtained using primary cultures of human RPE cells, but cultures took noticeably longer to establish on BMSF compared with tissue culture plastic. These findings encourage further studies of BMSF as a substrate for RPE cell transplantation.

Shadforth AM; George KA; Kwan AS; Chirila TV; Harkin DG

2012-06-01

180

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

International Nuclear Information System (INIS)

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

1024-01-00

 
 
 
 
181

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

Directory of Open Access Journals (Sweden)

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

Kui-Hua Zhang; Qiao-Zhen Yu; Xiu-Mei Mo

2011-01-01

182

Modification of human cancellous bone using Thai silk fibroin and gelatin for enhanced osteoconductive potential.  

UK PubMed Central (United Kingdom)

The modification of human cancellous bone (hBONE) with silk fibroin/gelatin (SF/G) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxysuccini-mide (NHS) crosslinking was established. The SF/G solutions at a weight ratio of 50/50 and the solution concentrations of 1, 2, and 4 wt % were studied. SF/G sub-matrix was formed on the surface and inside pore structure of hBONE. All hBONE scaffolds modified with SF/G showed smaller pore sizes, less porosity, and slightly lower compressive modulus than unmodified hBONE. SF/G sub-matrix was gradually biodegraded in collagenase solution along 4 days. The hBONE scaffolds modified with SF/G, particularly at 2 and 4 wt % solution concentrations, promoted attachment, proliferation, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (MSC), comparing to the original hBONE. The highest cell number, ALP activity and calcium production were observed for MSC cultured on the hBONE scaffolds modified with 4 wt % SF/G. The mineralization was also remarkably induced in the cases of modified hBONE scaffolds as observed from the deposited calcium phosphate by EDS. The modification of hBONE with SF/G was, therefore, the promising method to enhance the osteoconductive potential of human bone graft for bone tissue engineering.

Vorrapakdee R; Kanokpanont S; Ratanavaraporn J; Waikakul S; Charoenlap C; Damrongsakkul S

2013-03-01

183

Direct electrochemistry and electrocatalysis of heme-proteins in regenerated silk fibroin film  

Energy Technology Data Exchange (ETDEWEB)

A biocompatible silk fibroin (SF) film provided a feasible microenvironment for heme-proteins to direct electron transfer on graphite electrodes (GE). Myoglobin (Mb), hemoglobin (Hb), horseradish peroxidase (HRP), and catalase (Cat) incorporated in SF films exhibited a pair of well-defined, nearly reversible cyclic voltammetric peaks, corresponding to the reaction of hemeFe (III) + e {sup {yields}} hemeFe (II). The formal potential (E {sup 0}), the apparent coverage ({gamma}) and the electron transfer rate constant (k {sub s}) of four proteins in SF films were evaluated by analyzing the cyclic voltammograms (CVs) of heme-proteins. The formal potential was pH dependent, suggesting that proton ion was involved in the reaction. Ultraviolet visible (UV-vis) spectra and reflectance absorbance infrared (RAIR) spectra indicated that heme-proteins in SF films were not grossly denatured. The structure of heme-proteins-SF films was investigated using scanning electron microscopy (SEM) and RAIR. It indicated that there existed intermolecular interaction between heme-proteins and SF and this governed their different morphology in SF films. Hydrogen peroxide and nitric oxide were catalytically reduced by the heme-proteins in SF films, showing the potential applicability of the heme-proteins-SF films as the new type of biosensors based on the protein film voltammetry.

Wu Yunhua [Department of Chemistry, Wuhan University, Wuhan 430072 (China); State Key Laboratories of Transducer Technology, Chinese Academy of Sciences, Beijing 100080 (China); Shen Qiuchan [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu Shengshui [Department of Chemistry, Wuhan University, Wuhan 430072 (China) and State Key Laboratories of Transducer Technology, Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: sshu@whu.edu.cn

2006-02-03

184

Morphology and thermal stability of silk fibroin/starch blended microparticles  

Directory of Open Access Journals (Sweden)

Full Text Available In the present study biodegradable microparticles of silk fibroin (SF)/starch blends were prepared by a simple water-in-oil emulsion solvent diffusion technique. SF/starch blended solution and ethyl acetate were used as water and oil phases, respectively. The influence of SF/starch ratios on characteristics of the blended microparticles was investigated. The SF conformation of microparticle matrices from FTIR analysis was changed from random coil to ?-sheet form by blending with starch. The blended microparticles had lower dissolution in water than those of SF and starch microparticles. The 1/3 (w/w) SF/starch blended microparticles exhibited the lowest dissolution. The SF and starch microparticles showed irregular and deflated shapes, respectively. The blended microparticles were nearly spherical in shapes and smaller sizes. Thermal stability of the blended microparticles slightly increased with the starch blended ratio. The results suggested that SF conformational transition, thermal stability, morphology and dissolution of the blended microparticles can be adjusted by varying the blended ratio.

2010-01-01

185

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-09-15

186

Effect of polyaspartic acid on hydroxyapatite deposition in silk fibroin blend films  

Directory of Open Access Journals (Sweden)

Full Text Available Polyaspartic acid/silk fibroin/hydroxyapatite (PASP/SF-HA) composites have been synthesized by biomimetic processing. SF solution was mixed with different contents of PASP to prepare the PASP/SF blend membranes. After ethanol treatment and premineralization process, the blend membranes were immersed into 1.5 simulated body fluid (1.5 SBF) for 24 h to induce apatite deposition at 37±0.5°C. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results revealed that a conformation transition of SF occurred after the addition of PASP and ethanol treatment. The FTIR and XRD results also confirmed that the main component of apatite deposition was HA. Scanning electron microscopy (SEM) showed that the content of HA increased with increasing PASP concentration .Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP) results revealed that the Ca/P molar ratio could reach 1.45, which was close to the Ca/P ratio of apatite. It was appropriate to conclude that the increasing content of PASP had a distinct effect on HA deposition in the blend films.

2010-01-01

187

Morphology, Secondary Structure and Thermal Properties of Silk Fibroin/Gelatin Blend Film  

Directory of Open Access Journals (Sweden)

Full Text Available This study aimed to prepare Silk Fibroin (SF) and Gelatin (G) blend film and study its morphology, secondary structure and thermal properties compared to native SF and G films. The films were prepared from the SF solution by casting on the polystyrene plates. They were investigated their secondary structure by fourier transform-infrared (FTIR) spectroscopy, morphology using Scanning Electron Microscope (SEM). In addition, Thermogravimetric Analysis (TG) and Differential TG (DTG) were used for thermal properties investigation. The results found that the SF/G blend film composed of both ?-helix and ?-sheet structures which were similar characteristics of the native SF and G. This result was similar to the TG and DTG analysis according to blending between SF and G is not enhancing thermal stability of the film. However, changes in some absorption bands and temperatures were also observed from the blend film. The result suggested that chemical interaction and hydrogen bonding between SF and G could be formed. The formation could be affected to the uniform of the surface throughout the film under SEM.

Ong-chiari Watcharin; Srisuwan Yaowalak; Simcheur Wilaiwan; Srihanam Prasong

2009-01-01

188

Silk Fibroin/Gelatin Hybrid Films for Medical Applications: Study on Chlorhexidine Diacetate  

Directory of Open Access Journals (Sweden)

Full Text Available This study aimed to prepare silk fibroin (SF)/gelatin (G) hybrid films by a solvent evaporation method for loading chlorhexidine diacetate (CHX). The SF and G solution in different ratios were mixed with CHX and placed on the 5 cm polystyrene plates before drying to obtain hybrid films. The films were determined their secondary structures and thermal properties by using Fourier transform infrared (FT-IR) spectrometer and thermogravimetric analysis (TGA), respectively. The results found that all of film composed of ?-helix and ?-sheet structures. However, differences of the ?-helix and ?-sheet structures were differed according to each component. The hybrid films showed soft texture and decreased of brittle compared to SF film only when the G content increased. Thermal properties of the films indicated that decomposition temperature profiles of all films did not differ dramatically, however, combination of characteristics both SF and G were appeared in hybrid films. The releasing rate of CHX-loaded in the films was found that the CHX has released from the SF film in higher rate than hybrid and G films, respectively. It is a promising that polarity, flexibility as well as component ratio of each polymer play important role on the releasing of CHX.

Simchuer Wilaiwan; Srisuwan Yaowalak; Baimark Yodthong; Srihanam Prasong

2010-01-01

189

Study of synthesis of nano-hydroxyapatite using a silk fibroin template  

Energy Technology Data Exchange (ETDEWEB)

Nano-hydroxyapatite (HA) was directly synthesized on a silk fibroin (SF) template using the property of SF being soluable in a concentrated CaCl{sub 2} solution as a HA source of calcium at pH 7.4 and room temperature. The microstructure and bonding state were investigated by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry-thermogravimetry analysis (DSC-TG) and transmission electron microscopy (TEM). The results indicated that the HA crystals were poorly crystallized with a rod-like shape of 20-60 nm length and 10-20 nm diameter. Strong molecular interactions and chemical bonds might be present between SF and HA. There were other nucleation sites such as carbonyl (-C-O) and amine (-N-H-) groups on SF molecules besides the carboxyl (-COOH) and hydroxyl (-OH) groups previously reported. During the formation of HA, the coordination action between specific functional groups on SF and calcium ions (Ca{sup 2+}) played an important role. The crystallinity of HA was improved and had an orientation growth along (0 0 2) at the presence of SF, resulting in a structure similar to natural bone. It was concluded that SF could regulate the structure and morphology of HA effectively. (communication)

Wang Jing; Yu Feng; Qu Lijie; Meng Xiangcai [Provincial Key Laboratory of Biomaterials, Jiamusi University, Jiamusi 154007 (China); Wen, G [School of Materials Science and Engineering, Harbin Institute of Technology, Heilongjiang Province 150001 (China)

2010-08-01

190

In vitro Degradation Behavior of Bombyx mori Silk Fibroin Films Exposure to Protease XXIII  

Directory of Open Access Journals (Sweden)

Full Text Available Proteolytic activity of protease XXIII on Silk Fibroin (SF) films was studied. The films were prepared from the SF solution by casting on the polystyrene plates and used as substrate for enzymatic degradation. The SF films were incubated with 1.0 mg mL-1 protease XXIII at 37°C up to 21 days. After incubation, those of secondary structure and thermal behavior of the SF films were investigated. FT-IR spectra indicated that the SF films predominantly ?-structure. There was found that secondary structure of the films did not change even at 21 days of incubation times. However, slightly decreased of FTIR spectra were also observed by shoulder absorption peaks. The result suggested that some crystalline regions might be digested by the enzyme. This related to the thermal stability from thermogravimetric analysis since the SF films gradually decreased their thermal stability followed the increasing of time exposure to protease XXIII. It is a promising that protease XXIII could be digested SF and will be used this enzyme as a model system for enzymatic study on SF.

K. Nuanchai; S. Prasong; S. Wilaiwan

2009-01-01

191

Silk fibroin/chondroitin sulfate/hyaluronic acid ternary scaffolds for dermal tissue reconstruction.  

UK PubMed Central (United Kingdom)

The fabrication of new dermal substitutes providing mechanical support and cellular cues is urgently needed in dermal reconstruction. Silk fibroin (SF)/chondroitin sulfate (CS)/hyaluronic acid (HA) ternary scaffolds (95-248?m in pore diameter, 88-93% in porosity) were prepared by freeze-drying. By the incorporation of CS and HA with the SF solution, the chemical potential and quantity of free water around ice crystals could be controlled to form smaller pores in the SF/CS/HA ternary scaffold main pores and improve scaffold equilibrium swelling. This feature offers benefits for cell adhesion, survival and proliferation. In vivo SF, SF/HA and SF/CS/HA (80/5/15) scaffolds as dermal equivalents were implanted onto dorsal full-thickness wounds of Sprague-Dawley rats to evaluate wound healing. Compared to SF and SF/HA scaffolds, the SF/CS/HA (80/5/15) scaffolds promoted dermis regeneration, related to improved angiogenesis and collagen deposition. Further, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) expression in the SF/CS/HA (80/5/15) groups were investigated by immunohistochemistry to assess the mechanisms involved in the stimulation of secretion of VEGF, PDGF and bFGF and accumulation of these growth factors related to accelerated wound process. These new three-dimensional ternary scaffolds offer potential for dermal tissue regeneration.

Yan S; Zhang Q; Wang J; Liu Y; Lu S; Li M; Kaplan DL

2013-06-01

192

Elimination of large particulate units from silk fibroin PLD films by post-treatments  

Energy Technology Data Exchange (ETDEWEB)

After depositing silk fibroin (SF) thin films by pulsed IR-laser deposition, extraordinarily large particulate units up to several micrometers were observed. They include debris from the target and severely agglomerated protein units. Occurrence of those large particles was found to be minimum on the vertical substrate. We tried to eliminate large particulate units by two post-treatment operations, i.e. dry gaseous blow-off (GBO) and rinsing in water under simultaneous ultrasonication (WSU). Change in the surface structure by these post-treatments was observed by optical and electron microscopes with varying area from 1mm square down to 1{mu}m square. GBO turned out to be suitable to eliminate the lightly attached particulates of 1-10{mu}m, mostly those pulled out from the target while preserving morphological and chemical properties of smallest units underneath. WSU, on the other hand, pelt off more strongly attached surface irregularities. However, morphological change with an increase in the surface roughness in the range of 1nm was also observed after WSU. The latter might be associated with possible sonochemical effects.

Nakayama, S [Technofarm Axesz Co., Ltd., 4-4-27-703 Aobadai, Meguro, Tokyo 153-0042 (Japan); Senna, M [Technofarm Axesz Co., Ltd., 4-4-27-703 Aobadai, Meguro, Tokyo 153-0042 (Japan)

2007-04-15

193

Electrospun silk fibroin nanofibers in different diameters support neurite outgrowth and promote astrocyte migration.  

UK PubMed Central (United Kingdom)

Nerve tissue engineering has been one of the promising strategies for regenerative treatment in patients suffering from neural tissue loss, but considerable challenges remain before it is able to progress toward clinical application. It has been demonstrated that transplantation of cells in combination with physically or chemically modified biomaterials provides better environments for neurite outgrowth and further promotes axonal regeneration in animal models of spinal cord injury. In this study, neurons and astrocytes were incorporated into 400-nm, 800-nm, and 1200-nm electrospun Bombyx mori silk fibroin (SF) materials to investigate the effects of scaffold-diameter in regulating and directing cell behaviors. ?-III-tubulin immunofluorescence analyses reveal that SF nanofibers with smaller diameters are more favorable to the development and maturation of subventricular zone-derived neurons than 1200-nm SF scaffolds. In addition, astrocytes exhibited well-arranged glial fibrillary acidic protein (GFAP) expression on SF scaffolds, and a significant increase in cell-spreading area was observed on 400-nm but not 1200-nm SF scaffolds. Moreover, a significantly enhanced migration efficiency of astrocytes grown on SF scaffolds was verified, which highlights the guiding roles of SF nanofibers to the migratory cells. Overall, our results may provide valuable information to develop effective tissue remodeling substrates and to optimize existing biomaterials for neural tissue engineering applications.

Qu J; Wang D; Wang H; Dong Y; Zhang F; Zuo B; Zhang H

2013-09-01

194

Fabrication and characterization of bioactive silk fibroin/wollastonite composite scaffolds  

Energy Technology Data Exchange (ETDEWEB)

Composite scaffolds of silk fibroin (SF) with bioactive wollastonite were prepared by freeze-drying. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy analysis showed that random coil and {beta}-sheet structure co-existed in the SF scaffold. The mechanical performance, surface hydrophilicity and water-uptake capacity of the composite scaffolds were improved compared with those of pure SF scaffold. The bioactivity of the composite scaffold was evaluated by soaking in a simulated body fluid (SBF), and formation of a hydroxycarbonate apatite (HCA) layer was determined by FT-IR and XRD. The results showed that the SF/wollastonite composite scaffold was bioactive as it induced the formation of HCA on the surface of the composite scaffold after soaking in SBF for 5 days. In vitro cell attachment and proliferation tests showed that the composite scaffold was a good matrix for the growth of L929 mouse fibroblast cells. Consequently, the incorporation of wollastonite into the SF scaffold can enhance both the mechanical strength and bioactivity of the scaffold, which suggests that the SF/wollastonite composite scaffold may be a potential biomaterial for tissue engineering.

Zhu Hailin [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Xiasha Higher Education Zone, Zhejiang Sci-Tech University, Hangzhou, 310018 (China); Department of Chemistry, Xiasha Higher Education Zone, Zhejiang Sci-Tech University, Hangzhou, 310018 (China); Shen Jinyu; Feng Xinxing; Zhang Huapeng; Guo Yuhai [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Xiasha Higher Education Zone, Zhejiang Sci-Tech University, Hangzhou, 310018 (China); Chen Jianyong, E-mail: cjy@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Xiasha Higher Education Zone, Zhejiang Sci-Tech University, Hangzhou, 310018 (China)

2010-01-01

195

Tip-induced micropatterning of silk fibroin protein using in situ solution atomic force microscopy.  

UK PubMed Central (United Kingdom)

Silk fibroin (SF) is a promising candidate for a variety of application in the fields of tissue engineering, drug delivery, and biomedical optics. Recent research has already begun to explore the construction of nano- and micropatterned SF films under ambient environment. The structure and biocompatibility of SF are dependent on SF state (solution or solid) and the method of drying the SF solution to prepare various biomaterials such as films, sponges, and fibers. Therefore, it is important to explore the construction of SF nano- and micropatterns under aqueous solution. This paper reports a novel application of atomic force microscopy (AFM) under liquid for direct deposition of the relatively hydrophobic protein SF onto hydrophilic mica. We demonstrate that the AFM tip, in either the contact or the tapping mode, can fabricate SF micropatterns on mica with controlled surface topography. We show that the deposition process requires a mechanical force-induced SF sol-gel transition followed by a transfer to the mica surface at the tip-surface contact, and the efficiency of this process depends on not only AFM operation mode but also the SF bulk concentration, the SF amount on mica, and the AFM tip spring constant.

Zhong J; Ma M; Zhou J; Wei D; Yan Z; He D

2013-02-01

196

Fabrication and intermolecular interactions of silk fibroin/hydroxybutyl chitosan blended nanofibers.  

Science.gov (United States)

The native extracellular matrix (ECM) is composed of a cross-linked porous network of multifibril collagens and glycosaminoglycans. Nanofibrous scaffolds of silk fibroin (SF) and hydroxybutyl chitosan (HBC) blends were fabricated using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and trifluoroacetic acid (TFA) as solvents to biomimic the native ECM via electrospinning. Scanning electronic microscope (SEM) showed that relatively uniform nanofibers could be obtained when 12% SF was blended with 6% HBC at the weight ratio of 50:50. Meanwhile, the average nanofibrous diameter increased when the content of HBC in SF/HBC blends was raised from 20% to 100%. Fourier transform infrared spectra (FTIR) and (13)C nuclear magnetic resonance (NMR) showed SF and HBC molecules existed in hydrogen bonding interactions but HBC did not induce conformation of SF transforming from random coil form to ?-sheet structure. X-ray diffraction (XRD) confirmed the different structure of SF/HBC blended nanofibers from both SF and HBC. Thermogravimetry-Differential thermogravimetry (TG-DTG) results demonstrated that the thermal stability of SF/HBC blend nanofibrous scaffolds was improved. The results indicated that the rearrangement of HBC and SF molecular chain formed a new structure due to stronger hydrogen bonding between SF and HBC. These electrospun SF/HBC blended nanofibers may provide an ideal tissue engineering scaffold and wound dressing. PMID:21731435

Zhang, Kui-Hua; Yu, Qiao-Zhen; Mo, Xiu-Mei

2011-03-30

197

Fabrication and intermolecular interactions of silk fibroin/hydroxybutyl chitosan blended nanofibers.  

UK PubMed Central (United Kingdom)

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

Zhang KH; Yu QZ; Mo XM

2011-01-01

198

Mesenchymal stem cell-seeded multilayered dense collagen-silk fibroin hybrid for tissue engineering applications.  

Science.gov (United States)

Tissue engineering of multilayered constructs that model complex tissues poses a significant challenge for regenerative medicine. In this study, a three-layered scaffold consisting of an electrospun silk fibroin (SF) mat sandwiched between two dense collagen (DC) layers was designed and characterized. It was hypothesized that the SF layer would endow the DC-SF-DC construct with enhanced mechanical properties (e.g., apparent modulus, tensile strength, and toughness), while the surrounding DC layers provide an extracellular matrix-like environment for mesenchymal stem cell (MSC) growth. MSC-seeded DC-SF-DC hybrids were produced using the plastic compression technique and characterized morphologically, chemically, and mechanically. Moreover, MSC viability was assessed for up to 1 wk in culture. Scaffold analyses confirmed compaction and integration of the meso-scaled multilayered DC-SF-DC hybrid, which was reflected in a significantly higher toughness value when compared to DC and SF alone. MSCs directly incorporated into the DC layers remained viable for up to day 7. The ease of multilayered construct fabrication, enhanced biomechanical properties, along with uniformity of cell distribution confirmed the possibility for the incorporation and segregation of different cell types within distinct layers for the regeneration of complex tissues, such as skin, or central nervous system dura mater. PMID:21751393

Ghezzi, Chiara E; Marelli, Benedetto; Muja, Naser; Hirota, Nobuaki; Martin, James G; Barralet, Jake E; Alessandrino, Antonio; Freddi, Giuliano; Nazhat, Showan N

2011-08-26

199

Mesenchymal stem cell-seeded multilayered dense collagen-silk fibroin hybrid for tissue engineering applications.  

UK PubMed Central (United Kingdom)

Tissue engineering of multilayered constructs that model complex tissues poses a significant challenge for regenerative medicine. In this study, a three-layered scaffold consisting of an electrospun silk fibroin (SF) mat sandwiched between two dense collagen (DC) layers was designed and characterized. It was hypothesized that the SF layer would endow the DC-SF-DC construct with enhanced mechanical properties (e.g., apparent modulus, tensile strength, and toughness), while the surrounding DC layers provide an extracellular matrix-like environment for mesenchymal stem cell (MSC) growth. MSC-seeded DC-SF-DC hybrids were produced using the plastic compression technique and characterized morphologically, chemically, and mechanically. Moreover, MSC viability was assessed for up to 1 wk in culture. Scaffold analyses confirmed compaction and integration of the meso-scaled multilayered DC-SF-DC hybrid, which was reflected in a significantly higher toughness value when compared to DC and SF alone. MSCs directly incorporated into the DC layers remained viable for up to day 7. The ease of multilayered construct fabrication, enhanced biomechanical properties, along with uniformity of cell distribution confirmed the possibility for the incorporation and segregation of different cell types within distinct layers for the regeneration of complex tissues, such as skin, or central nervous system dura mater.

Ghezzi CE; Marelli B; Muja N; Hirota N; Martin JG; Barralet JE; Alessandrino A; Freddi G; Nazhat SN

2011-10-01

200

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

Science.gov (United States)

In the present study, we reported fabrication and skin benefit of a novel vitamin E (VE)-loaded silk fibroin (SF) nanofibrous mats. RRR-?-Tocopherol polyethylene glycol 1000 succinate (VE TPGS), a water-soluble derivative of VE, was incorporated into SF nanofiber successfully by aqua solution electrospinning for the first time. Morphology of the composite nanofibers changed with the different amount of VE TPGS: a ribbon-like shape for lower loading dose of VE TPGS, while a round shape for higher loading dose (more than 4% (wt/wt) based on the weight of SF). After treated with 75% (v/v) ethanol vapor, the composite nanofibrous mats showed an excellent water-resistant ability. In vitro study disclosed a sustained release behavior of VE TPGS disassociated from the nanofibrous mats. The mouse skin fibroblasts (L929 cells) cultured on the VE-loaded SF nanofibrous mats spread and proliferated much better than on cover slips. Moreover, the incorporation of VE TPGS was found strengthening the ability of SF nanofibrous mats on protecting the cells against oxidation stress induced by tert-butyl hydroperoxide. Our data presented impressive skin benefits of this VE-loaded SF nanofibrous mats, suggesting a promising applicative potential of this novel product on personal skin care, tissue regeneration and other related area. PMID:23396066

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

2013-02-05

 
 
 
 
201

Synthesis and characterization of dense membranes of silk fibroin with glycerin;Sintese e caracterizacao de membranas densas de fibroina de seda com glicerina  

Energy Technology Data Exchange (ETDEWEB)

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)

Silva, Mariana F.; Moraes, Mariana A. de; Weska, Raquel F.; Nogueira, Grinia M.; Beppu, Marisa M., E-mail: beppu@feq.unicamp.b [Universidade Estadual de Campinas (FEQ/UNICAMP), SP (Brazil). Faculdade de Engenharia Quimica

2009-07-01

202

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

UK PubMed Central (United Kingdom)

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

Cao TT; Wang YJ; Zhang YQ

2013-01-01

203

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-04-01

204

Radiation degradation of silk  

Energy Technology Data Exchange (ETDEWEB)

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)

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

205

Fabrication and characterization of silk fibroin/bioactive glass composite films  

Energy Technology Data Exchange (ETDEWEB)

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

Zhu Hailin [Engineering Research Center for Eco-Dyeing and Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou, 310018 (China); Department of Chemistry, Xiasha Higher Education Zone, Zhejiang Sci-Tech University, Hangzhou, 310018 (China); Liu Na; Feng Xinxing [Engineering Research Center for Eco-Dyeing and Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou, 310018 (China); Chen Jianyong, E-mail: cjy@zstu.edu.cn [Engineering Research Center for Eco-Dyeing and Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou, 310018 (China)

2012-05-01

206

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-06-01

207

Effect of initial cell seeding density on 3D-engineered silk fibroin scaffolds for articular cartilage tissue engineering.  

UK PubMed Central (United Kingdom)

The repair of articular cartilage defects poses a continuing challenge. Cartilage tissue engineering through the culture of chondrocytes seeded in 3D porous scaffolds has the potential for generating constructs that repair successfully. It also provides a platform to study scaffold-cell and cell-cell interactions. The scaffold affects the growth and morphology of cells growing on it, and concomitantly, cells affect the properties of the resultant tissue construct. Silk fibroin protein from Antheraea mylitta, a non-mulberry Indian tropical tasar silkworm, is a potential biomaterial for diverse applications due to its widespread versatility as a mechanically robust, biocompatible, tissue engineering material. Analysis of silk fibroin scaffolds seeded with varying initial densities (25, 50 and 100 million cells/ml) and cultured for 2 weeks showed that thickness and wet weight increased by 60-70% for the highest cell density, and DNA, GAG and collagen content of the cartilaginous constructs increased with increasing cell density. Mechanical characterization of the constructs elucidated that the highest density constructs had compressive stiffness and modulus 4-5 times that of cell-free scaffolds. The present results indicate the importance of cell seeding density in the rapid formation of a functional cartilaginous tissue.

Talukdar S; Nguyen QT; Chen AC; Sah RL; Kundu SC

2011-12-01

208

Effect of initial cell seeding density on 3D-engineered silk fibroin scaffolds for articular cartilage tissue engineering.  

Science.gov (United States)

The repair of articular cartilage defects poses a continuing challenge. Cartilage tissue engineering through the culture of chondrocytes seeded in 3D porous scaffolds has the potential for generating constructs that repair successfully. It also provides a platform to study scaffold-cell and cell-cell interactions. The scaffold affects the growth and morphology of cells growing on it, and concomitantly, cells affect the properties of the resultant tissue construct. Silk fibroin protein from Antheraea mylitta, a non-mulberry Indian tropical tasar silkworm, is a potential biomaterial for diverse applications due to its widespread versatility as a mechanically robust, biocompatible, tissue engineering material. Analysis of silk fibroin scaffolds seeded with varying initial densities (25, 50 and 100 million cells/ml) and cultured for 2 weeks showed that thickness and wet weight increased by 60-70% for the highest cell density, and DNA, GAG and collagen content of the cartilaginous constructs increased with increasing cell density. Mechanical characterization of the constructs elucidated that the highest density constructs had compressive stiffness and modulus 4-5 times that of cell-free scaffolds. The present results indicate the importance of cell seeding density in the rapid formation of a functional cartilaginous tissue. PMID:21906805

Talukdar, Sarmistha; Nguyen, Quynhhoa T; Chen, Albert C; Sah, Robert L; Kundu, Subhas C

2011-09-08

209

Silk Fibroin/Chitosan Blend Films Loaded Methylene Blue as a Model for Polar Molecular Releasing: Comparison between Thai Silk Varieties  

Directory of Open Access Journals (Sweden)

Full Text Available The aims of this study were to prepare Silk Fibroin (SF)/Chitosan (CS) blend films loaded Methylene Blue (MB) and characterize their related properties. The SF was obtained from various Thai silk varieties locally called Nang Lai, Mo and Kaki. The blend films were prepared by mixing the SF, CS and MB solutions before pouring on polystyrene plates. They were then taken to an oven at 40C for 3 days to obtain the films. In addition, each native SF silk variety and CS films were also prepared as control. SEM micrographs showed that native Nang Lai film appeared the bead like particles while other film types were smooth. Comparison between the blend films, Mo variety film has smooth surfaces while Nang Lai and Kaki films composed of flat particles covered their surfaces. FTIR results indicated that all of native SF has similar absorption bands at amide regions which coexisted of a-helix and -sheet structures. Moreover, SF blended with CS showed strong bands at amide II, exhibit -sheet structure. The blend film of Mo variety rapidly decomposed whereas Nang Lai was the lowest. In vitro releasing study indicated that MB released more quickly at the initial 30 min which Mo variety was the slowest.

Srihanam Prasong

2011-01-01

210

Incorporation of Exogenous RGD Peptide and Inter-Species Blending as Strategies for Enhancing Human Corneal Limbal Epithelial Cell Growth on Bombyx mori Silk Fibroin Membranes  

Directory of Open Access Journals (Sweden)

Full Text Available While fibroin isolated from the cocoons of domesticated silkworm Bombyx mori supports growth of human corneal limbal epithelial (HLE) cells, the mechanism of cell attachment remains unclear. In the present study we sought to enhance the attachment of HLE cells to membranes of Bombyx mori silk fibroin (BMSF) through surface functionalization with an arginine-glycine-aspartic acid (RGD)-containing peptide. Moreover, we have examined the response of HLE cells to BMSF when blended with the fibroin produced by a wild silkworm, Antheraea pernyi, which is known to contain RGD sequences within its primary structure. A procedure to isolate A. pernyi silk fibroin (APSF) from the cocoons was established, and blends of the two fibroins were prepared at five different BMSF/APSF ratios. In another experiment, BMSF surface was modified by binding chemically the GRGDSPC peptide using a water-soluble carbodiimide. Primary HLE were grown in the absence of serum on membranes made of BMSF, APSF, and their blends, as well as on RGD-modified BMSF. There was no statistically significant enhancing effect on the cell attachment due to the RGD presence. This suggests that the adhesion through RGD ligands may have a complex mechanism, and the investigated strategies are of limited value unless the factors contributing to this mechanism become better known.

Laura J. Bray; Shuko Suzuki; Damien G. Harkin; Traian V. Chirila

2013-01-01

211

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

Science.gov (United States)

Electrospinning of fibrous scaffolds containing nano-hydroxyapatite (nHAp) embedded in a matrix of functional biomacromolecules offers an attractive route to mimicking the natural bone tissue architecture. Functional fibrous substrates will support cell attachment, proliferation and differentiation, while the role of HAp is to induce cells to secrete extracellular matrix (ECM) for mineralization to form bone. Electrospinning of biomaterials composed of polyhydroxybutyrate-co-(3-hydroxyvalerate) with 2% valerate fraction (PHBV), nano-hydroxyapatite (nHAp), and Bombyx mori silk fibroin essence (SF), Mw=90KDa, has been achieved for nHAp and SF solution concentrations of 2 (w/vol) % each and 5 (w/vol) % each. The structure and properties of the nanocomposite fibrous membranes were investigated by means of Scanning Electron Microscopy in combination with Energy Dispersive X-Ray Analysis (SEM/EDX), Fourier Transformed Infrared Spectroscopy (FT-IR), uniaxial tensile and compressive mechanical testing, degradation tests and in vitro bioactivity tests. SEM images showed smooth, uniform and continuous fibre deposition with no bead formation, and fibre diameters of between 10 and 15?m. EDX and FT-IR confirmed the presence of nHAp and SF. After one month in deionised water, tests showed less than 2% weight loss with the samples retaining their fibrous morphology, confirming that this material biodegrades slowly. After 28days of immersion in Simulated Body Fluid (SBF) an apatite layer was visible on the surface of the fibres, proving their bioactivity. Preliminary in vitro biological assessment showed that after 1 and 3days in culture, cells were attached to the fibres, retaining their morphology while presenting a flattened appearance and elongated shape on the surface of fibres. Young's modulus was found to increase from 0.7kPa (±0.33kPa) for electrospun samples of PHBV only to 1.4kPa (±0.54kPa) for samples with 2 (w/vol) % each of nHAp and SF. Samples prepared with 5 (w/vol) % each of nHAp and SF did not show a similar improvement. PMID:24094204

Pa?cu, Elena I; Stokes, Joseph; McGuinness, Garrett B

2013-08-20

212

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

Science.gov (United States)

We evaluated the use of a combination of human insulin gene-modified umbilical cord mesenchymal stromal cells (hUMSCs) with silk fibroin 3D scaffolds for adipose tissue engineering. In this study hUMSCs were isolated and cultured. HUMSCs infected with Ade-insulin-EGFP were seeded in fibroin 3D scaffolds with uniform 50-60?µm pore size. Silk fibroin scaffolds with untransfected hUMSCs were used as control. They were cultured for 4?days in adipogenic medium and transplanted under the dorsal skins of female Wistar rats after the hUMSCs had been labelled with chloromethylbenzamido-1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (CM-Dil). Macroscopical impression, fluorescence observation, histology and SEM were used for assessment after transplantation at 8 and 12?weeks. Macroscopically, newly formed adipose tissue was observed in the experimental group and control group after 8 and 12?weeks. Fluorescence observation supported that the formed adipose tissue originated from seeded hUMSCs rather than from possible infiltrating perivascular tissue. Oil red O staining of newly formed tissue showed that there was substantially more tissue regeneration in the experimental group than in the control group. SEM showed that experimental group cells had more fat-like cells, whose volume was larger than that of the control group, and degradation of the silk fibroin scaffold was greater under SEM observation. This study provides significant evidence that hUMSCs transfected by adenovirus vector have good compatibility with silk fibroin scaffold, and adenoviral transfection of the human insulin gene can be used for the construction of tissue-engineered adipose. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23509085

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

2013-03-19

213

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

UK PubMed Central (United Kingdom)

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

Li SL; Liu Y; Hui L

2013-03-01

214

Electrospinning-aligned and random polydioxanone-polycaprolactone-silk fibroin-blended scaffolds: geometry for a vascular matrix  

Energy Technology Data Exchange (ETDEWEB)

Extracellular matrices are arranged with a specific geometry based on tissue type and mechanical stimulus. For blood vessels in the body, preferential alignment of fibers is in the direction of repetitive force. Electrospinning is a controllable process which can result in fiber alignment and randomization depending on the parameters utilized. In this study, arterial grafts composed of polycaprolactone (PCL), polydioxanone (PDO) and silk fibroin in blends of 100:0 and 50:50 for both PCL:silk and PDO:silk were investigated to determine if fibers could be controllably aligned using a mandrel rotational speed ranging from 500 to 8000 revolutions per minute (RPM). Results revealed that large- and small-diameter mandrels produced different degrees of fiber alignment based on a fast Fourier transform of scanning electron microscope images. Uniaxial tensile testing further demonstrated scaffold anisotropy through changes in peak stress, modulus and strain at break at mandrel rotational speeds of 500 and 8000 RPM, causing peak stress and modulus for PCL to increase 5- and 4.5-fold, respectively, as rotational speed increased. Additional mechanical testing was performed on grafts using dynamic compliance, burst strength and longitudinal strength displaying that grafts electrospun at higher rotational rates produced stiffer conduits which had lower compliance and higher burst strength compared to the lower mandrel rotational rate. Scaffold properties were found to depend on several parameters in the electrospinning process: mandrel rotational rate, polymer type, and mandrel size. Vascular scaffold design under anisotropic conditions provided interesting insights and warrants further investigation.

McClure, M J; Sell, S A; Bowlin, G L [Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284 (United States); Ayres, C E; Simpson, D G, E-mail: glbowlin@vcu.ed [Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298 (United States)

2009-10-15

215

Bioengineered silk proteins to control cell and tissue functions.  

UK PubMed Central (United Kingdom)

Silks are defined as protein polymers that are spun into fibers by some lepidoptera larvae such as silkworms, spiders, scorpions, mites, and flies. Silk proteins are usually produced within specialized glands in these animals after biosynthesis in epithelial cells that line the glands, followed by secretion into the lumen of the gland prior to spinning into fibers.The most comprehensively characterized silks are from the domesticated silkworm (Bombyx mori) and from some spiders (Nephila clavipes and Araneus diadematus). Silkworm silk has been used commercially as biomedical sutures for decades and in textile production for centuries. Because of their impressive mechanical properties, silk proteins provide an important set of material options in the fields of controlled drug release, and for biomaterials and scaffolds for tissue engineering. Silkworm silk from B. mori consists primarily of two protein components, fibroin, the structural protein of silk fibers, and sericins, the water-soluble glue-like proteins that bind the fibroin fibers together. Silk fibroin consists of heavy and light chain polypeptides linked by a disulfide bond. Fibroin is the protein of interest for biomedical materials and it has to be purified/extracted from the silkworm cocoon by removal of the sericin. Characteristics of silks, including biodegradability, biocompatibility, controllable degradation rates, and versatility to generate different material formats from gels to fibers and sponges, have attracted interest in the field of biomaterials. Cell culture and tissue formation using silk-based biomaterials have been pursued, where appropriate cell adhesion, proliferation, and differentiation on or in silk biomaterials support the regeneration of tissues. The relative ease with which silk proteins can be processed into a variety of material morphologies, versatile chemical functionalization options, processing in water or solvent, and the related biological features of biocompatibility and enzymatic degradability make these proteins interesting candidates for biomedical applications.

Preda RC; Leisk G; Omenetto F; Kaplan DL

2013-01-01

216

Influence of Philosamia ricini Silk Fibroin Components on Morphology, Secondary Structure and Thermal Properties of Chitosan Biopolymer Film  

Directory of Open Access Journals (Sweden)

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

S. Prasong; K. Nuanchai; S. Wilaiwan

2009-01-01

217

Microstructure and Chemical States of Hydroxyapatite/silk Fibroin Nanocomposites Synthesized via A Wet-mechanochemical Route  

Energy Technology Data Exchange (ETDEWEB)

Hydroxyapaptite (HAp)/silk fibroin (SF) nanocomposites were prepared via a wet-mechanochemical route at room temperature. The results reveal that the inorganic phase in the composites is carbonate-substituted HAp containing 2.9-3.1 wt% of carbonate ions. The primary HAp crystals are rod-like in shape with a typical size of 20-30 nm in length and 8-10 nm in width, and lattice parameters a = 9.423 A, c = 6.888 A. The self-assembled HAp crystals along their c-axes aggregate into bundles, which are connected with SF fibrils. Consequently, a three-dimensional porous network is formed in the composite, which is beneficial to inducing new bone formation in practical implantation.

Wang Li; Nemoto, Rei; Senna, Mamoru [Keio University, Department of Applied Chemistry, Faculty of Science and Technology (Japan)], E-mail: senna@applc.keio.ac.jp

2002-12-15

218

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

Energy Technology Data Exchange (ETDEWEB)

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

Kweon, HaeYong; Yeo, Joo-hong; Lee, Kwang-gill [Applied Sericulture and Apiculture Division, National Institute of Agricultural Science and Technology, Suwon 441100 (Korea, Republic of); Lee, Hyun Chul; Na, Hee Sam [Department of Microbiology and Research Institute of Medical Sciences, Chonnam National University Medical School, Kwangju (Korea, Republic of); Won, Young Ho [Department of Dermatology, Chonnam National University Medical School, Kwangju (Korea, Republic of); Cho, Chong Su [School of Agricultural Biotechnology, Seoul National University, Seoul 151742 (Korea, Republic of)], E-mail: chocs@plaza.snu.ac.kr

2008-09-01

219

Three-Dimensional Porous Network Structure Developed in Hydroxyapatite-Based Nanocomposites Containing Enzyme Pretreated Silk Fibroin  

Energy Technology Data Exchange (ETDEWEB)

Chemically modified silk fibroin (SF) with an enzyme, Proteinase K, has been incorporated into hydroxyapatite (HAp)-based nanocomposite attempting to strengthen the interfacial bonding between the mineral phase and the organic matrix. Particular emphasis is laid on the microstructure and microhardness of the composite along with the crystallographic properties of HAp. The whisker-like HAp crystallites of nanometer size show the preferential self-assembly and anisotropic crystal growth along c-axis. There appears porous microstructure with 70% of open porosity and pore size distribution of 10-115 um in the composite. Attributed to the enzyme modification, the crosslinkage between HAp clusters and SF matrix is improved to form an enhanced three-dimensional network extending throughout the composites and an increase of 35% in microhardness of the composite is achieved as well.

Wang Li; Nemoto, Rei; Senna, Mamoru [Keio University, Department of Applied Chemistry, Faculty of Science and Technology (Japan)], E-mail: senna@applc.keio.ac.jp

2004-02-15

220

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-05-25

 
 
 
 
221

Regenerated silk fibroin scaffold and infrapatellar adipose stromal vascular fraction as feeder-layer: a new product for cartilage advanced therapy.  

UK PubMed Central (United Kingdom)

Articular cartilage has limited repair and regeneration potential, and the scarcity of treatment modalities has motivated attempts to engineer cartilage tissue constructs. The use of chondrocytes in cartilage tissue engineering has been restricted by the limited availability of these cells, their intrinsic tendency to lose their phenotype during the expansion, as well as the difficulties during the first cell adhesion to the scaffold. Aim of this work was to evaluate the intra-articular adipose stromal vascular fraction attachment on silk fibroin scaffold to promote chondrocytes adhesion and proliferation. Physicochemical characterization has demonstrated that three-dimensionally organized silk fibroin scaffold is an ideal biopolymer for cartilage tissue engineering; it allows cell attachment, scaffold colonization, and physically cell holding in the area that must be repaired; the use of adipose-derived stem cells is a promising strategy to promote adhesion and proliferation of chondrocytes to the scaffold as an autologous human feeder layer.

Chlapanidas T; Faragò S; Mingotto F; Crovato F; Tosca MC; Antonioli B; Bucco M; Lucconi G; Scalise A; Vigo D; Faustini M; Marazzi M; Torre ML

2011-07-01

222

Silk fibroin/montmorillonite nanocomposites: effect of pH on the conformational transition and clay dispersion.  

UK PubMed Central (United Kingdom)

By adjusting the solution pH value below the isoelectric point (pI) of silk fibroin (SF) protein, the SF was in the cation state and it could interact strongly with unmodified anionic montmorillonite (MMT) surface. In this way, novel SF-MMT nanocomposites with good clay dispersion were successfully obtained, which were confirmed by X-ray diffraction and transmission electron microscopy. Further 1H CRAMPS and 13C CP/MAS NMR experimental results revealed that beta-sheet content of SF was remarkably enhanced for nanocomposite prepared below the pI of SF (SF-MMTA) due to the strong interaction between MMT and SF. In SF-MMTA nanocomposite, clay layers acting as an efficient nucleator could efficiently enhance the beta-sheet crystallization. On the contrary, SF preserved the native random coil conformation in SF-MMTN nanocomposites due to the weak interaction between MMT and SF. A tentative model was suggested and used to explain the mechanism of clay dispersion and conformational transition of silk protein.

Dang Q; Lu S; Yu S; Sun P; Yuan Z

2010-07-01

223

Synthesis and cellular compatibility of Co-doped ZnO particles in silk-fibroin peptides.  

UK PubMed Central (United Kingdom)

Co-doped ZnO particles were successfully prepared via a facile biomineralization process in the template of silk-fibroin (SF) peptides at room temperature, and SF peptides were coated onto the surface of particles. The ratio of Zn/Co in reactive solution could substantially influence the morphology of as-prepared particles, and the rough spherical particles including some nanoparticles of 50 nm diameters could be obtained at 4:1 ratio of Zn/Co. The saturation magnetization of SF-coated Co-ZnO particles was 8.63 emu/g, much larger than that of Co-ZnO without SF. L929 cell test revealed that the Co-doped ZnO particles had a good cellular compatibility at the concentration of less than 0.25 mg/mL due to silk-peptide coating, indicating that the prepared Co-doped ZnO particles have a potential for the biomedical applications.

Zou Y; Huang Z; Wang Y; Liao X; Yin G; Gu J

2013-02-01

224

Isolation of a Clone Encoding a Second Dragline Silk Fibroin. (Reannouncement with New Availability Information).  

Science.gov (United States)

Spider dragline silk is a unique protein fiber possessing both high tensile strength and high elasticity. A partial cDNA clone for one dragline silk protein (Spidroin 1) was previously isolated. However, the predicted amino acid sequence could not account...

M. B. Hinnman R. V. Lewis

1992-01-01

225

Biodegradation of Silk Biomaterials  

Directory of Open Access Journals (Sweden)

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

Yang Cao; Bochu Wang

2009-01-01

226

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

UK PubMed Central (United Kingdom)

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 affinity to SF and their size was inferior to 200 nm when theoretical CaP/silk ratios were between 4 and 16 wt.%, as determined by scanning electron microscopy. The CaP particles displayed a uniform distribution in the scaffolds at both microscopic and macroscopic scales as observed by backscattered scanning electron microscopy and micro-computed tomography, respectively. The prepared scaffolds presented self-mineralization capability and no cytotoxicity confirmed by in vitro bioactivity tests and cell viability assays, respectively. CONCLUSION: These results indicated that the produced silk/nano-CaP scaffolds could be suitable candidates for bone-tissue-engineering applications.

Yan LP; Silva-Correia J; Correia C; Caridade SG; Fernandes EM; Sousa RA; Mano JF; Oliveira JM; Oliveira AL; Reis RL

2013-03-01

227

Creation of macropores in electrospun silk fibroin scaffolds using sacrificial PEO-microparticles to enhance cellular infiltration.  

UK PubMed Central (United Kingdom)

Electrospun scaffolds are widely used in tissue engineering; however, a common problem is the poor cell infiltration because of the small pore size and tightly packed structure of these fibrous scaffolds. To address this issue, a novel technique was developed to fabricate electrospun silk fibroin (SF) scaffolds with rather macropores and high porosity using electrospraying-generated PEO microparticles as porogen. The morphology and pore size of MPES scaffolds were evaluated by scanning electron microscopy. It was revealed that MPES scaffold had a relatively loose structure with an increase of mean pore size (i.e., approx. 30 ?m of MPES vs. approx. 5 ?m of traditional electrospun scaffolds (TES) and porosity (i.e., 95% vs. 84% of TES). Culture of mouse 3T3 fibroblast in TES and MPES scaffold revealed that both scaffolds could support cell attachment, spread and proliferation. Yet, cell inflitration in vitro under the static culture condition only occurred in the MPES scaffold. Subcutaneous implantation of scaffolds in rats further confirmed that the tissue ingrowth was more efficient in the MPES scaffold compared to TES scaffold. Thus, the use of PEO microparticles as porogen was a feasible and effective method for creating macroporous electrospun SF scaffold, which provided an alternative to address the limitation of cell infiltration associated with electrospun fibrous scaffold. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.

Wang K; Xu M; Zhu M; Su H; Wang H; Kong D; Wang L

2013-04-01

228

Preparation and in vitro evaluation of silk fibroin microspheres produced by a novel ultra-fine particle processing system.  

UK PubMed Central (United Kingdom)

The objective of this study was to prepare silk fibroin SF microspheres containing the enhanced green fluorescent protein (EGFP) by using a novel ultra-fine particle processing system (UPPS) and to evaluate the microspheres as possible carriers for long-term delivery of sensitive biologicals. The drug content, encapsulation efficiency, and in vitro release were evaluated by Microplate Absorbance Reader. The particle size distribution and morphology of the microspheres were analyzed by Malvern Master Sizer 2000 and scanning electron microscopy. The distribution of EGFP and the interactions between SF and EGFP were investigated by Confocal Laser Scanning Microscopy, FTIP, Raman and NMR spectroscopy. The results showed that spherical microspheres with narrow size distribution, glossy and dense surface were successfully manufactured by using UPPS technology and over 95% of EGFP encapsulation efficiency and uniform drug distribution in the microspheres were achieved. Furthermore, a burst free and sustained release of encapsulated EGFP for a period of 50 days in deionized water was obtained. In conclusion, the novel UPPS technology could be used to manufacture SF matrix microspheres as a potential long-term protein delivery system to improve patient compliance and convenience.

Wen X; Peng X; Fu H; Dong Y; Han K; Su J; Wang Z; Wang R; Pan X; Huang L; Wu C

2011-09-01

229

Cytotoxicity and endothelial cell adhesion of lyophilized and irradiated bovine pericardium modified with silk fibroin and chitosan.  

UK PubMed Central (United Kingdom)

Grafts of biological tissues have been used since the 1960s as an alternative to the mechanical heart prostheses. Nowadays, the most consolidated treatment to bovine pericardial (BP) bioprostheses is the crosslinking with glutaraldehyde (GA), although GA may induce calcification in vivo. In previous work, our group demonstrated that electron beam irradiation applied to lyophilized BP in the absence of oxygen promoted crosslinks among collagen fibers of BP tissue. In this work, the incorporation of silk fibroin (SF) and chitosan (CHIT) in the BP not treated with GA was studied. The samples were irradiated and then analyzed for their cytotoxicity and the ability of adhesion and growth of endothelial cells. Initially, all samples showed cytotoxicity. However, after a few washing cycles, the cytotoxicity due to acetic acid and ethanol residues was removed from the biomaterial making it suitable for the biofunctional test. The samples modified with SF/CHIT and electron beam irradiated favored the adhesion and growth of endothelial cells throughout the tissue.

Rodas AC; Polak R; Hara PH; Lee EI; Pitombo RN; Higa OZ

2011-05-01

230

Cytotoxicity and endothelial cell adhesion of lyophilized and irradiated bovine pericardium modified with silk fibroin and chitosan.  

Science.gov (United States)

Grafts of biological tissues have been used since the 1960s as an alternative to the mechanical heart prostheses. Nowadays, the most consolidated treatment to bovine pericardial (BP) bioprostheses is the crosslinking with glutaraldehyde (GA), although GA may induce calcification in vivo. In previous work, our group demonstrated that electron beam irradiation applied to lyophilized BP in the absence of oxygen promoted crosslinks among collagen fibers of BP tissue. In this work, the incorporation of silk fibroin (SF) and chitosan (CHIT) in the BP not treated with GA was studied. The samples were irradiated and then analyzed for their cytotoxicity and the ability of adhesion and growth of endothelial cells. Initially, all samples showed cytotoxicity. However, after a few washing cycles, the cytotoxicity due to acetic acid and ethanol residues was removed from the biomaterial making it suitable for the biofunctional test. The samples modified with SF/CHIT and electron beam irradiated favored the adhesion and growth of endothelial cells throughout the tissue. PMID:21595719

Rodas, Andrea C D; Polak, Roberta; Hara, Priscila H; Lee, Emily I; Pitombo, Ronaldo N M; Higa, Olga Z

2011-05-01

231

The robust hydrogel hierarchically assembled from a pH sensitive peptide amphiphile based on silk fibroin.  

Science.gov (United States)

Supramolecular polymers can be formed by self-assembly of designed subunits to yield highly ordered materials. In this paper, hierarchically structured materials, from molecules to nanofibers to macroscopical hydrogel, were fabricated by pH-induced assembly of C(12)-GAGAGAGY, a peptide amphiphile (PA) based on silk fibroin. Due to the different acid dissociation constants of the carboxyl and phenolic hydroxyl groups on tyrosine residue (Y), the PAs showed unique pH sensitive assembly and aggregation behaviors. It was found that not only the molecular-scale assemblies of these PAs gradually changed from cylindrical nanofibers to nanoribbons with the decreasing of pH value from 11 to 8 but also most of nanoribbons aggregated into parallel bundles in such a case. Further decrease of pH value resulted in a hierarchically structured robust and plastic hydrogel, of which the rheological moduli reached around 10(5) Pa. Moreover, noodle-like hydrogel fibers with bundles of nanoribbons aggregated parallel along the long axis in them could be steadily prepared under shear force. Taking the pH-sensitive reversible sol-gel transition, high modulus and plasticity into account, the hydrogel is believed to have significant potential applications in tissue engineering or as the biocompatible adhesives. PMID:23822204

Guo, Hui; Zhang, Jinming; Xu, Tao; Zhang, Zhidong; Yao, Jinrong; Shao, Zhengzhong

2013-07-19

232

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

Energy Technology Data Exchange (ETDEWEB)

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

Tanaka, Toshimitsu [Research Institute for Cell Engineering (RICE), National Institute of Advanced Industrial Science and Technology (AIST) 3-11-46 Nakoji, Amagasaki, Hyogo 661-0974 (Japan); First Department of Oral and Maxillofacial Surgery, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-0063 (Japan); Hirose, Motohiro [Research Institute for Cell Engineering (RICE), National Institute of Advanced Industrial Science and Technology (AIST), 3-11-46 Nakoji, Amagasaki, Hyogo 661-0974 (Japan)]. E-mail: motohiro-hirose@aist.go.jp; Kotobuki, Noriko [Research Institute for Cell Engineering (RICE), National Institute of Advanced Industrial Science and Technology (AIST), 3-11-46 Nakoji, Amagasaki, Hyogo 661-0974 (Japan); Ohgushi, Hajime [Research Institute for Cell Engineering (RICE), National Institute of Advanced Industrial Science and Technology (AIST), 3-11-46 Nakoji, Amagasaki, Hyogo 661-0974 (Japan); Furuzono, Tsutomu [Department of Biomedical Engineering, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565 (Japan); Innovation Plaza Osaka, Japan Science and Technology Agency (JST), 3-1-10 Techno-stage, Izumi, Osaka 594-1144 (Japan); Sato, Junichi [First Department of Oral and Maxillofacial Surgery, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-0063 (Japan)

2007-05-16

233

Influence of the protocol used for fibroin extraction on the mechanical properties and fiber sizes of electrospun silk mats.  

UK PubMed Central (United Kingdom)

Silk fibroin (SF) was regenerated using three of the most common protocols described in the bibliography for the dissolution of raw SF (LiBr 9.3M, CaCl2 50 wt.% or CaCl2:EtOH:H2O 1:2:8 in molar ratio). The integrity of regenerated SF in aqueous solution was analyzed by SDS-PAGE and different profiles of degradation were observed depending on the protocol used. This fact was found to affect also the aqueous solubility of the freeze dried protein. These different SFs were used to produce electrospun mats using SF solutions of SF 17 wt.% in 1,1,1,1',1',1'-hexafluoro-2-propanol (HFIP) and significant differences in fiber sizes, elongation and ultimate strength values were found. This work provides a global overview of the manner that different methods of SF extraction can affect the properties of electrospun SF-mats and consequently it should be considered depending on the use they are going to be made for.

Aznar-Cervantes SD; Vicente-Cervantes D; Meseguer-Olmo L; Cenis JL; Lozano-Pérez AA

2013-05-01

234

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-12-15

235

Cardiac repair using chitosan-hyaluronan/silk fibroin patches in a rat heart model with myocardial infarction.  

UK PubMed Central (United Kingdom)

The cardiac repair of myocardial infarction (MI) hearts of rats using chitosan-hyaluronan/silk fibroin (chitosan-HYA/SF) cardiac patches was examined after eight weeks of implantation. Rats with implantations of chitosan-HYA/SF patches (CHS group) significantly (P<0.05) reduced the dilation of the inner diameter of left ventricle (LV) (4.27 ± 0.29 mm), increased wall thickness of LV (1.5 ± 0.13 mm) and improved the fractional shortening of LV of hearts (LVFS) (42.8 ± 2.4%) compared with those values of LVs of rats without implants (MI group) (e.g., 5.92 ± 0.39 mm, 1.2 ± 0.06 mm and 31.5±1.4%, respectively). Moreover, blood vessel-like structures in MI regions of LVs in the CHS group were widely distributed while none was found in the MI group. The CHS group significantly improved the secretion of paracrine factors, such as VEGF in the MI regions of LVs (P<0.05, n=4), relative to that in the MI group. In conclusion, chitosan-HYA/SF cardiac patches are promising biomaterials for the cardiac repair of MI rat hearts.

Chi NH; Yang MC; Chung TW; Chou NK; Wang SS

2013-01-01

236

Development of micro-structural units in the silk fibroin thin films prepared by near-infrared pulsed laser deposition  

Energy Technology Data Exchange (ETDEWEB)

Development of micro-structural units in a silk fibroin (SF) thin film deposited on Si (100) by using 1064 nm pulsed laser beam was examined. The smallest units ranging ca 10-20 nm were always observed in more or less uniformly dispersed states, which we coined as smallest protein units. At the same time, we frequently observed much larger chunks. Formation of such chunks was suppressed by choosing smaller fluence, shorter deposition time or by sputtering intermittently. When the laser fluence does not appreciably exceed the empirically determined threshold of 1.7 J/cm{sup 2}, the basic secondary structure of SF, i.e. anti-parallel {beta}-sheet, was well preserved, as confirmed by Fourier transform infrared spectroscopy. Since the target material exhibits only very small extent of absorption of 1064 nm beam, we suspected that formation of radicals and free electrons and subsequent optical breakdown are mainly responsible for the deposition process, although a number of mechanistic questions remain open. The present near-infrared pulsed laser deposition technique seems attractive since it is free from appreciable damage of the protein secondary structure and solubility of the protein species, and a compact, relatively inexpensive laser source suffices.

Nakayama, S. [Technofarm Axesz Co., Ltd., 4-4-27-703 Aobadai, Meguro, Tokyo 153-0042 (Japan) and Nara Machinery Co., Ltd., 2-5-7, Jounan-jima, Tokyo 143-0002 (Japan)]. E-mail: nakayama@nara-m.co.jp; Nagare, S. [Technofarm Axesz Co., Ltd., 4-4-27-703 Aobadai, Meguro, Tokyo 153-0042 (Japan); Nara Machinery Co., Ltd., 2-5-7, Jounan-jima, Tokyo 143-0002 (Japan); Senna, M. [Technofarm Axesz Co., Ltd., 4-4-27-703 Aobadai, Meguro, Tokyo 153-0042 (Japan); Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Yokohama 223-8522 (Japan)

2006-12-05

237

The Effect of Temperatures and Incubation Times on Some Properties of Silk Fibroin/Chitosan Blend Films  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this work was to study the effect of temperatures and incubation times on Silk Fibroin (SF)/Chitosan (CS) blend films properties. The films were firstly prepared by mixing the SF and CS solution in homogeneously blended, then cast on the polystyrene culture plates before taking into the oven at 40C for 3 days. The obtained SF/CS blend films were treated at 90 and 120C, each for 30, 60 and 90 min, respectively. All of films were characterized for their morphology and secondary structures by using SEM and FTIR, respectively. The results showed that SF/CS films have homogeneous texture without phase separation. However, they also appeared some particles dispersed and embedded on their surfaces. The surfaces of the films slightly increased smooth texture when increased both temperatures and incubation times. The results were also noted that the characteristics were varied by those different temperatures. FTIR spectra indicated that the absorption bands at amide regions (I, II and III) of the SF were similar profile. Moreover, treatment the blended films with temperatures resulted to changed the secondary structures of the films. This means the ratio of -sheet were increased. It can be expected that water evaporation by increasing temperature resulted to make the molecules of SF and CS close up and help to form H-bonds between them.

Prasong Srihanam

2011-01-01

238

In vivo biodegradation of porous silk fibroin films implanted beneath the skin and muscle of the rat.  

UK PubMed Central (United Kingdom)

Since the bioresorption process has a strong impact not only on the mechanical properties of the biomaterial but also on the extent of tissue regeneration, in vivo biodegradation of absorbable porous biomaterials plays a key role in tissue repair and wound healing. In the present work, porous silk fibroin films (PSFFs) were prepared by a freeze-drying method and then implanted beneath the dorsal skin and the femoral skeletal muscle of the rat. The objective was to study the rate of biodegradation of the PSFFs in different tissues, each with its distinct metabolic rate. In addition we examined the relationship between the biodegradation rate and tissue-regeneration rate semi-quantitatively by incorporating histology, microscopy and image analysis methods. Furthermore, based on our previous findings, we also explored the relationship between in vitro and in vivo rates of biodegradation. The results suggest that the PSFFs experience a similar biodegradation process regardless of the type of tissue in which they are implanted, in spite of the higher metabolic rate of the skeletal muscle. In addition, the in vitro biodegradation rate of the PSFFs was comparable to that of both skin and skeletal muscle, suggesting that an in vitro biodegradation test could be used to predict in vivo performance.

Guan G; Wang L; Li M; Bai L

2013-01-01

239

The robust hydrogel hierarchically assembled from a pH sensitive peptide amphiphile based on silk fibroin.  

UK PubMed Central (United Kingdom)

Supramolecular polymers can be formed by self-assembly of designed subunits to yield highly ordered materials. In this paper, hierarchically structured materials, from molecules to nanofibers to macroscopical hydrogel, were fabricated by pH-induced assembly of C(12)-GAGAGAGY, a peptide amphiphile (PA) based on silk fibroin. Due to the different acid dissociation constants of the carboxyl and phenolic hydroxyl groups on tyrosine residue (Y), the PAs showed unique pH sensitive assembly and aggregation behaviors. It was found that not only the molecular-scale assemblies of these PAs gradually changed from cylindrical nanofibers to nanoribbons with the decreasing of pH value from 11 to 8 but also most of nanoribbons aggregated into parallel bundles in such a case. Further decrease of pH value resulted in a hierarchically structured robust and plastic hydrogel, of which the rheological moduli reached around 10(5) Pa. Moreover, noodle-like hydrogel fibers with bundles of nanoribbons aggregated parallel along the long axis in them could be steadily prepared under shear force. Taking the pH-sensitive reversible sol-gel transition, high modulus and plasticity into account, the hydrogel is believed to have significant potential applications in tissue engineering or as the biocompatible adhesives.

Guo H; Zhang J; Xu T; Zhang Z; Yao J; Shao Z

2013-08-01

240

Silk gland sericin protein membranes: fabrication and characterization for potential biotechnological applications.  

Science.gov (United States)

This study describes the potential use of silk gland sericin protein as a biocompatible natural biopolymer in its native form. The membranes were fabricated using native silk sericin protein extracted from middle silk gland of Antheraea mylitta, a non-mulberry tropical tasar silkworm without using any cross-linking agent. The fabricated membranes were biophysically characterized and optimized for cell culture. Silk sericin protein extracted from gland contained higher amount of beta-sheets, which increased upon treatment with ethanol as observed by FTIR and XRD. The membranes did show robustness, good mechanical strength and high temperature stability. Cytocompatibility of the membranes was evaluated by MTT assay and cell cycle analysis using feline fibroblast cells. Morphology of growing cells was assessed by confocal microscopy that indicated normal spreading and proliferation on the silk sericin membranes. The membranes showed low inflammatory response as observed assaying TNF alpha release. This study reveals the potential of native silk sericin protein from silk gland as biocompatible biopolymer for potential biomedical applications. PMID:19808068

Dash, Biraja C; Mandal, Biman B; Kundu, S C

2009-10-04

 
 
 
 
241

Silk gland sericin protein membranes: fabrication and characterization for potential biotechnological applications.  

UK PubMed Central (United Kingdom)

This study describes the potential use of silk gland sericin protein as a biocompatible natural biopolymer in its native form. The membranes were fabricated using native silk sericin protein extracted from middle silk gland of Antheraea mylitta, a non-mulberry tropical tasar silkworm without using any cross-linking agent. The fabricated membranes were biophysically characterized and optimized for cell culture. Silk sericin protein extracted from gland contained higher amount of beta-sheets, which increased upon treatment with ethanol as observed by FTIR and XRD. The membranes did show robustness, good mechanical strength and high temperature stability. Cytocompatibility of the membranes was evaluated by MTT assay and cell cycle analysis using feline fibroblast cells. Morphology of growing cells was assessed by confocal microscopy that indicated normal spreading and proliferation on the silk sericin membranes. The membranes showed low inflammatory response as observed assaying TNF alpha release. This study reveals the potential of native silk sericin protein from silk gland as biocompatible biopolymer for potential biomedical applications.

Dash BC; Mandal BB; Kundu SC

2009-12-01

242

Morphology and composition of the spider major ampullate gland and dragline silk.  

UK PubMed Central (United Kingdom)

Spider silk is made of unique proteins-spidroins-secreted and stored as a protein solution (dope) in specialized glands. The major ampullate gland, source of the dragline silk, is composed of a tail, a sac and an elongated duct. For this gland, several different types of epithelial cells and granules have been described, but it is largely unknown how they correlate with spidroin production. It is also not settled what parts of the large spidroins end up in the final silk, and it has been suggested that the N-terminal domain (NT) is lacking. Here we show that NT is present in the dope and throughout dragline silk fibers, including the skin layer, and that the major ampullate tail and sac consist of three different and sharply demarcated zones (A-C), each with a distinct epithelial cell type. Finally, we show that spidroins are produced in the A and B zone epithelia, while the C zone granules lack spidroins.

Andersson M; Holm L; Ridderstråle Y; Johansson J; Rising A

2013-08-01

243

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

UK PubMed Central (United Kingdom)

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

Xu S; Yong L; Wu P

2013-02-01

244

Biocompatibility study of a silk fibroin-chitosan scaffold with adipose tissue-derived stem cells in vitro.  

UK PubMed Central (United Kingdom)

The use of tissue engineering technology in the repair of spinal cord injury (SCI) is a topic of current interest. The success of the repair of the SCI is directly affected by the selection of suitable seed cells and scaffold materials with an acceptable biocompatibility. In this study, adipose tissue-derived stem cells (ADSCs) were incorporated into a silk fibroin-chitosan scaffold (SFCS), which was constructed using a freeze-drying method, in order to assess the biocompatibility of the ADSCs and the SFCS and to provide a foundation for the use of tissue engineering technology in the repair of SCI. Following the seeding of the cells onto the scaffold, the adhesion characteristics of the ADSCs and the SFCS were assessed. A significant difference was observed between the experimental group (a composite of the ADSCs with the SFCS) and the control group (ADSCs without the scaffold) following a culture period of 6 h (P<0.05). The differences in the results at the following time-points were statistically insignificant (P>0.05). The use of an MTT assay to assess the proliferation of the cells on the scaffold revealed that there were significant differences between the experimental and control groups following culture periods of 2 and 4 days (P<0.05). However, the results at the subsequent time-points were not statistically significantly different (P>0.05). Scanning electron microscopy (SEM), using hematoxylin and eosin (H&E) staining, was used to observe the cellular morphology following seeding, and this revealed that the cells displayed the desired morphology. The results indicate that ADSCs have a good biocompatibility with a SFCS and thus provide a foundation for further studies using tissue engineering methods for the repair of SCI.

Ji W; Zhang Y; Hu S; Zhang Y

2013-08-01

245

The extraction of fibroin protein from Bombyx mori silk cocoon: Optimization of process parameters  

Directory of Open Access Journals (Sweden)

Full Text Available Optimization of protein extraction using silk cocoon was carried out by the design of experiment(DOE) to obtain the response surface methodology ( RSM ). Box-Behnken rotatable design was used tocreate an experimental program to provide data to model the effects of various factors on protein extractionefficiency. The variables chosen were sodium carbonate concentration ( 1 X ), Lithum bromide concentration( 2 X ) and temperature ( 3 X ). The mathematical relationship between protein extraction efficiency and threesignificant independent variables can be approximated by a second order quadratic model. RSM wasused to describe the individual and interactive effects of three variables at three levels, combined accordingto a Box-Behnken Design. The coefficient of determination (2 R ) for the model is 0.9761. Probability value( P < 0.0001) demonstrates a very high significance for the regression model indicating that Box-BehnkenDesign can be applied to the protein extraction from silk cocoon, and it is an economical way of obtainingthe maximum amount of information with the fewest experiments.

Mahesh Kumar Sah; Arvind Kumar; Pramanik K.

2010-01-01

246

Silk fibroins modify the atmospheric low temperature plasma-treated poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) film for the application of cardiovascular tissue engineering  

Directory of Open Access Journals (Sweden)

Full Text Available Tissue engineered scaffold is one of the hopeful therapies for the patients with organ or tissue damages. The key element for a tissue engineered scaffold material is high biocompatibility. Herein the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) film was irradiated by the low temperature atmospheric plasma and then coated by the silk fibroins (SF). After plasma treatment, the surface of PHBHHx film became rougher and more hydrophilic than that of original film. The experiment of PHBHHx flushed by phosphate buffer solution (PBS) proves that the coated SF shows stronger immobilization on the plasma-treated film than that on the untreated film. The cell viability assay demonstrates that SF-coated PHBHHx films treated by the plasma significantly supports the proliferation and growth of the human smooth muscle cells (HSMCs). Furthermore, the scanning electron microscopy and hemotoylin and eosin (HE) staining show that HSMCs formed a cell sub-monolayer and secreted a large amount of extracellular matrix (ECM) on the films after one week's culture. The silk fibroins modify the plasma-treated PHBHHx film, providing a material potentially applicable in the cardiovascular tissue engi-neering.

Huaxiao Yang; Min Sun; Ping Zhou; Luanfeng Pan; Chungen Wu

2010-01-01

247

Bacterial cellulose nanocrystals-embedded silk nanofibers.  

Science.gov (United States)

Nanofibrous Bacterial cellulose nanocrystals (BCNs)-embedded silk fibroin were successfully fabricated using electrospinning. The morphology, structure and mechanical properties of the silk fibroin nanofibers were investigated at various BCNs concentrations from 0 to 7 wt%. SEM, TEM and XRD analyses were conducted to confirm the incorporation of the BCNs in the electrospun silk fibroin nanofibers. The average diameter of the silk fibroin/BCNs nanofibers increased from 230 to 430 nm according to the increasing of the BCNs ratio due to the rising solute content. The FT-IR spectra confirmed the conformational transition of the silk fibroin, from a random coil to a beta-sheet structure, which shows the enhanced mechanical properties of silk fibroin based nanofibers even with small amounts of the BCNs. Moreover, it was observed that the Young's modulus of the silk fibroin/BCNs nanofibers unexpectedly increased with the formation of BCNs with a percolation structure at a concentration between 3 and 5 wt%. PMID:22966722

Park, Doo Jin; Choi, Youngeun; Heo, Semi; Cho, Se Youn; Jin, Hyung-Joon

2012-07-01

248

Bacterial cellulose nanocrystals-embedded silk nanofibers.  

UK PubMed Central (United Kingdom)

Nanofibrous Bacterial cellulose nanocrystals (BCNs)-embedded silk fibroin were successfully fabricated using electrospinning. The morphology, structure and mechanical properties of the silk fibroin nanofibers were investigated at various BCNs concentrations from 0 to 7 wt%. SEM, TEM and XRD analyses were conducted to confirm the incorporation of the BCNs in the electrospun silk fibroin nanofibers. The average diameter of the silk fibroin/BCNs nanofibers increased from 230 to 430 nm according to the increasing of the BCNs ratio due to the rising solute content. The FT-IR spectra confirmed the conformational transition of the silk fibroin, from a random coil to a beta-sheet structure, which shows the enhanced mechanical properties of silk fibroin based nanofibers even with small amounts of the BCNs. Moreover, it was observed that the Young's modulus of the silk fibroin/BCNs nanofibers unexpectedly increased with the formation of BCNs with a percolation structure at a concentration between 3 and 5 wt%.

Park DJ; Choi Y; Heo S; Cho SY; Jin HJ

2012-07-01

249

New application of silk protein  

Energy Technology Data Exchange (ETDEWEB)

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)

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

2000-03-01

250

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)

2000-01-01

251

Characterization of Tetracycline-loaded Thai Silk Fibroin/Gelatin Blend Films  

Directory of Open Access Journals (Sweden)

Full Text Available This study was aimed to prepare SF/G blend films loaded tetracycline by a solvent evaporation method. Firstly silk cocoons were degummed and then dissolved by CaCl2:Ethanol:H2O (1:2:8 by mole). On another way, Gelatin (G) was prepared from gelatin powder. The mixture solution of SF/G ratios with 3:0, 2:1, 1:1, 1:2 and 0:3 were prepared before casting on the 5 cm polystyrene plates. All of films were investigated their morphology, chemical structures, thermal properties and percent transparency by using Scanning Electron Microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric Analyzer (TA) and UV-Vis spectrometer, respectively. The results found that the surfaces of blend films were gradually smooth without phase separation when the SF component decreased. The FTIR results of SF/G films showed strong regions for amide I, amide II and amide III which were the mixture characteristics of SF and G. The blend films rapidly decomposed in maximum rate after 300°C. The rate of weight lost depending on the content G meanwhile rapidly increased of weight lost when the G content was increased. The heat flow curves indicated that the blend films composed of multiple peaks of maximum decomposition temperatures as well as endo/exo-thermic. Finally, tetracycline could be interacted with G in excellent profile affected to the lowest of percent transparency.

Srihanam Prasong

2010-01-01

252

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

Science.gov (United States)

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

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

2009-07-01

253

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

International Nuclear Information System (INIS)

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

2009-01-01

254

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-15

255

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

Science.gov (United States)

Silk fibroin (SF) has been widely used as a wound dressing material due to its suitable physical and biological characteristics. In this study, a non-adhesive wound dressing which applies to cover the wound surface as an absorbent pad that would absorb wound fluid while accelerate wound healing was developed. The modification of SF fabrics by wax coating was purposed to prepare the non-adhesive wound dressing that is required in order to minimize pain and risk of repeated injury. SF woven fabrics were coated with different types of waxes including shellac wax, beeswax, or carnauba wax. Physical and mechanical properties of the wax-coated SF fabrics were characterized. It was clearly observed that all waxes could be successfully coated on the SF fabrics, possibly due to the hydrophobic interactions between hydrophobic domains of SF and waxes. The wax coating improved tensile modulus and percentage of elongation of the SF fabrics due to the denser structure and the thicker fibers coated. The in vitro degradation study demonstrated that all wax-coated SF fabrics remained up to 90% of their original weights after 7 weeks of incubation in lysozyme solution under physiological conditions. The wax coating did not affect the degradation behavior of the SF fabrics. A peel test of the wax-coated SF fabrics was carried out in the partial- and full-thickness wounds of porcine skin in comparison to that of the commercial wound dressing. Any wax-coated SF fabrics were less adhesive than the control, as confirmed by less number of cells attached and less adhesive force. This might be that the wax-coated SF fabrics showed the hydrophobic property, allowing the loosely adherence to the hydrophilic wound surface. In addition, the in vivo biocompatibility test of the wax-coated SF fabrics was performed in Sprague-Dawley rats with subcutaneous model. The irritation scores indicated that the carnauba wax-coated SF fabric was not irritant while the shellac wax or beeswax-coated SF fabrics were slightly irritant, comparing with the commercial wound dressing. Therefore, SF fabrics coated with waxes, particularly carnauba wax, would be promising choices of non-adhesive wound dressing. PMID:23313451

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

2013-01-09

256

Effect of juvenile hormone analog, methoprene on H-fibroin regulation during the last instar larval development of Corcyra cephalonica.  

UK PubMed Central (United Kingdom)

Juvenile hormone (JH) and 20-hydroxyecdysone (20E), co-ordinately orchestrate insect growth and development. The process of silk synthesis and secretion in lepidopteran insects is known to be under hormonal control. However, the role of JH in this process has not been demonstrated hitherto. The present study is aimed to elucidate the role of JH in H-fibroin regulation in Corcyra cephalonica, a serious lepidopteran pest. Reiterated amino acid stretches and the large molecular weight of H-fibroin render its cloning and characterization cumbersome. To address this, a commercially synthesized short amino acid peptide conjugated with a carrier protein was used to generate antibodies against the N-terminal region of H-fibroin. ELISA and immunoblot experiments demonstrated the sensitivity and specificity of antibody. Further, immunohistochemical analyses revealed the antibody's cross-reactivity with H-fibroins of C. cephalonica and Bombyx mori in the silk gland lumen. Quantitative RT-PCR and Western blot analysis demonstrated the tissue-specificity and developmental expression of H-fibroin. Hormonal studies revealed that JH alone does not alter the expression of H-fibroin. However, in the presence 20E, JH reverses the declined expression caused by 20E administration to normal levels. This study provides molecular evidence for the regulation of H-fibroin by the cumulative action of JH and 20E.

Chaitanya RK; Sridevi P; Senthilkumaran B; Dutta Gupta A

2013-01-01

257

DNA Synthesis in the Giant Nuclei of Insects - Control Machinery and Structures Observed in the Silk-Producing Gland of Bombyx Mori  

International Nuclear Information System (INIS)

The existence in many insect organs of giant nuclei without visible chromosomes raises the question of possible homologies between the chromatin structures of these nuclei and those of polytene nuclei or common euploid cells. Studies have been made of the nuclei in the silk-producing gland of Bombyx mori. The DNA synthesis is cyclic. During the third stage there are three successive synthesis cycles, which appear to be relatively autonomous in the individual nuclei. For more than 24 hours after moulting, however, synthesis is greatly reduced; moulting factors thus cause synchronization of all the nuclei. This leads to the conclusion that the triggering of a synthesis cycle is controlled by general factors external to the cell. At the end of larval development, DNA synthesis is suspended at the moment when large-scale secretion of silk begins. Evaluation of the pool of endogenic precursors of DNA shows that it is considerably reduced at the end of the DNA synthesis period. The hypothesis proposed is that large-scale synthesis of fibroin requires polarization of the metabolism, hence the depletion of the nucleotide pool and the end of DNA synthesis. DNA synthesis within a single nucleus is to some extent asynchronic. In particular, a well-defined, delayed-synthesis structure visible only in the female seems to be a possible homologue of a sex chromosome. Other asynchronisms are also apparent, though less clearly. Functional studies thus allow the supposition that in the giant nucleus replication units retain an individuality comparable to that of a polytene chromosome. These observations together lead to the conclusion that a nucleus in the silk-producing gland has physiological and structural characteristics similar to those of a polytene nucleus, differing from it essentially in the lesser degree of condensation of its structures. (author)

1968-01-01

258

Review structure of silk by raman spectromicroscopy: from the spinning glands to the fibers.  

Science.gov (United States)

Raman spectroscopy has long been proved to be a useful tool to study the conformation of protein-based materials such as silk. Thanks to recent developments, linearly polarized Raman spectromicroscopy has appeared very efficient to characterize the molecular structure of native single silk fibers and spinning dopes because it can provide information relative to the protein secondary structure, molecular orientation, and amino acid composition. This review will describe recent advances in the study of the structure of silk by Raman spectromicroscopy. A particular emphasis is put on the spider dragline and silkworm cocoon threads, other fibers spun by orb-weaving spiders, the spinning dope contained in their silk glands and the effect of mechanical deformation. Taken together, the results of the literature show that Raman spectromicroscopy is particularly efficient to investigate all aspects of silk structure and production. The data provided can lead to a better understanding of the structure of the silk dope, transformations occurring during the spinning process, and structure and mechanical properties of native fibers. PMID:21882171

Lefèvre, Thierry; Paquet-Mercier, François; Rioux-Dubé, Jean-François; Pézolet, Michel

2011-08-31

259

Review structure of silk by raman spectromicroscopy: from the spinning glands to the fibers.  

UK PubMed Central (United Kingdom)

Raman spectroscopy has long been proved to be a useful tool to study the conformation of protein-based materials such as silk. Thanks to recent developments, linearly polarized Raman spectromicroscopy has appeared very efficient to characterize the molecular structure of native single silk fibers and spinning dopes because it can provide information relative to the protein secondary structure, molecular orientation, and amino acid composition. This review will describe recent advances in the study of the structure of silk by Raman spectromicroscopy. A particular emphasis is put on the spider dragline and silkworm cocoon threads, other fibers spun by orb-weaving spiders, the spinning dope contained in their silk glands and the effect of mechanical deformation. Taken together, the results of the literature show that Raman spectromicroscopy is particularly efficient to investigate all aspects of silk structure and production. The data provided can lead to a better understanding of the structure of the silk dope, transformations occurring during the spinning process, and structure and mechanical properties of native fibers.

Lefèvre T; Paquet-Mercier F; Rioux-Dubé JF; Pézolet M

2012-06-01

260

Morphology and composition of the spider major ampullate gland and dragline silk.  

Science.gov (United States)

Spider silk is made of unique proteins-spidroins-secreted and stored as a protein solution (dope) in specialized glands. The major ampullate gland, source of the dragline silk, is composed of a tail, a sac and an elongated duct. For this gland, several different types of epithelial cells and granules have been described, but it is largely unknown how they correlate with spidroin production. It is also not settled what parts of the large spidroins end up in the final silk, and it has been suggested that the N-terminal domain (NT) is lacking. Here we show that NT is present in the dope and throughout dragline silk fibers, including the skin layer, and that the major ampullate tail and sac consist of three different and sharply demarcated zones (A-C), each with a distinct epithelial cell type. Finally, we show that spidroins are produced in the A and B zone epithelia, while the C zone granules lack spidroins. PMID:23837699

Andersson, Marlene; Holm, Lena; Ridderstråle, Yvonne; Johansson, Jan; Rising, Anna

2013-07-23

 
 
 
 
261

Study of the effects of different sterilization methods on the properties of dense and porous silk fibroin membranes;Estudo dos efeitos de diferentes metodos de esterilizacao nas propriedades de membranas densas de fibroina de seda  

Energy Technology Data Exchange (ETDEWEB)

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

Weska, Raquel F.; Moraes, Mariana A. de; Beppu, Marisa M., E-mail: raquelweska@terra.com.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica

2009-07-01

262

A silk fibroin based hepatocarcinoma model and the assessment of the drug response in hyaluronan-binding protein 1 overexpressed HepG2 cells.  

UK PubMed Central (United Kingdom)

Microenvironment around tumor cells plays an important role in its malignancy or invasiveness. Hyaluronan (HA), a major component of extracellular matrix is found to be elevated in most of cancerous niche/microenvironment and performs regulatory role in the progression of tumors and metastasis. Overexpression of the hyaladherin, hyaluronan-binding protein 1 (HABP1) in the hepatocarcinoma cells (HepG2) termed as HepR21 leads to enhanced cell proliferation with increased HA 'pool' associated with HA 'cables' indicating elevated tumorous potential under 2D culture conditions. For in vitro experimentation, scaffold based three dimensional niche modeling may have greater acceptance than conventional 2D culture condition. Thus, we have examined the influence of intrinsic properties of non-mulberry tropical tasar silk fibroin on the HepR21 cells in order to develop a 3D hepatocarcinoma construction to act as model. The scaffold of tasar silk fibroin of Antheraea mylitta when efficiently loaded with transformed hepatocarcinoma cells, HepR21; exhibits enhanced adhesiveness, viability, metabolic activity, proliferation and enlarged cellular morphology in 3D compared to its parent cell line HepG2, supporting the earlier observation made in 2D system. In addition, formation of multicellular aggregates, the indicator of tumor progression is also revealed in silk based 3D culture conditions. Further, the use of 4-MU (a hyaluronan synthase inhibitor) on HepR21 cells reduces the HA level and downregulates the expression of growth promoting factors like pAKT and PKC; while upregulating the expression of the tumor suppressor p53. Thus, 4-MU efficiently reduces the tumor potency associated with increased HA pool as well as HA cables and the effect of 4-MU doubling up as an anticancer agent in 2D and 3D are also comparable. The in vitro 3D multicellular model demonstrates the insight of hepatocarcinoma progression and offers the predictability of cellular response to transfection efficacy, drug treatment and therapeutic intervention.

Kundu B; Saha P; Datta K; Kundu SC

2013-12-01

263

A silk fibroin based hepatocarcinoma model and the assessment of the drug response in hyaluronan-binding protein 1 overexpressed HepG2 cells.  

Science.gov (United States)

Microenvironment around tumor cells plays an important role in its malignancy or invasiveness. Hyaluronan (HA), a major component of extracellular matrix is found to be elevated in most of cancerous niche/microenvironment and performs regulatory role in the progression of tumors and metastasis. Overexpression of the hyaladherin, hyaluronan-binding protein 1 (HABP1) in the hepatocarcinoma cells (HepG2) termed as HepR21 leads to enhanced cell proliferation with increased HA 'pool' associated with HA 'cables' indicating elevated tumorous potential under 2D culture conditions. For in vitro experimentation, scaffold based three dimensional niche modeling may have greater acceptance than conventional 2D culture condition. Thus, we have examined the influence of intrinsic properties of non-mulberry tropical tasar silk fibroin on the HepR21 cells in order to develop a 3D hepatocarcinoma construction to act as model. The scaffold of tasar silk fibroin of Antheraea mylitta when efficiently loaded with transformed hepatocarcinoma cells, HepR21; exhibits enhanced adhesiveness, viability, metabolic activity, proliferation and enlarged cellular morphology in 3D compared to its parent cell line HepG2, supporting the earlier observation made in 2D system. In addition, formation of multicellular aggregates, the indicator of tumor progression is also revealed in silk based 3D culture conditions. Further, the use of 4-MU (a hyaluronan synthase inhibitor) on HepR21 cells reduces the HA level and downregulates the expression of growth promoting factors like pAKT and PKC; while upregulating the expression of the tumor suppressor p53. Thus, 4-MU efficiently reduces the tumor potency associated with increased HA pool as well as HA cables and the effect of 4-MU doubling up as an anticancer agent in 2D and 3D are also comparable. The in vitro 3D multicellular model demonstrates the insight of hepatocarcinoma progression and offers the predictability of cellular response to transfection efficacy, drug treatment and therapeutic intervention. PMID:24016853

Kundu, Banani; Saha, Paramita; Datta, Kasturi; Kundu, Subhas C

2013-09-07

264

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

UK PubMed Central (United Kingdom)

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

Hajer J; Malý J; Reháková D

2013-01-01

265

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

Science.gov (United States)

Scanning electron microscopy and atomic force microscopy were used to study the silk spinning apparatus and silks of Harpactea rubicunda spiders. Three types of silk secretions that are produced by three kinds of silk spinning glands (ampullate, piriform, and pseudaciniform) and released through three types of spigots, were confirmed for both adult and juvenile spiders. Silk secretions for the construction of spider webs for shelter or retreat are produced by the pseudaciniform silk glands. Silk secretions that are released from spigots in the course of web construction are not processed by the legs during the subsequent process of hardening. Pairs of nanofibril bundles seemed to be part of the basic microarchitecture of the web silk fibers as revealed by AFM. These fiber bundles frequently not only overlap one another, but occasionally also interweave. This structural variability may strengthen the spider web. High-resolution AFM scans of individual nanofibrils show a distinctly segmented nanostructure. Each globular segment is ?30-40 nm long along the longitudinal axis of the fiber, and resembles a nanosegment of artificial fibroin described by Perez-Rigueiro et al. (2007). PMID:23034869

Hajer, Jaromír; Malý, Jan; Reháková, Dana

2012-10-04

266

Biospinning by silkworms: silk fiber matrices for tissue engineering applications.  

UK PubMed Central (United Kingdom)

The mechanism of biospinning of natural silk fibers has been an open issue for decades. In this report a natural bio-polymeric matrix based on biospun silk fibers obtained from Antheraea mylitta, a wild non-mulberry tropical tasar silkworm, is put forward for potential applications. This report deals with the conformational transitions of silk fibroin during the biospinning process and its potential to support cell adherence and proliferation. The silk fibers obtained were aligned into linear, mixed or random patterns forming interconnected, macroporous three-dimensional matrices. The matrices were morphologically and functionally characterized with respect to fiber diameter, crystallinity, mechanical strength and biocompatibility using feline fibroblast cells. Drawn silk fibers showed enhanced stability to protease treatment in comparison with naturally occurring native gland fibroin protein. A viability assay suggested biocompatibility of these matrices in vitro. Fluorescence and confocal microscopy indicated normal cell attachment, spreading and proliferation on these biospun silk matrices. The results provided evidence for the use of biospun silk matrices as natural, inexpensive and alternative substrata for tissue engineering applications.

Mandal BB; Kundu SC

2010-02-01

267

Biospinning by silkworms: silk fiber matrices for tissue engineering applications.  

Science.gov (United States)

The mechanism of biospinning of natural silk fibers has been an open issue for decades. In this report a natural bio-polymeric matrix based on biospun silk fibers obtained from Antheraea mylitta, a wild non-mulberry tropical tasar silkworm, is put forward for potential applications. This report deals with the conformational transitions of silk fibroin during the biospinning process and its potential to support cell adherence and proliferation. The silk fibers obtained were aligned into linear, mixed or random patterns forming interconnected, macroporous three-dimensional matrices. The matrices were morphologically and functionally characterized with respect to fiber diameter, crystallinity, mechanical strength and biocompatibility using feline fibroblast cells. Drawn silk fibers showed enhanced stability to protease treatment in comparison with naturally occurring native gland fibroin protein. A viability assay suggested biocompatibility of these matrices in vitro. Fluorescence and confocal microscopy indicated normal cell attachment, spreading and proliferation on these biospun silk matrices. The results provided evidence for the use of biospun silk matrices as natural, inexpensive and alternative substrata for tissue engineering applications. PMID:19716447

Mandal, Biman B; Kundu, Subhas C

2009-08-27

268

Solution structure of eggcase silk protein and its implications for silk fiber formation.  

UK PubMed Central (United Kingdom)

Spider silks are renowned for their excellent mechanical properties and biomimetic and industrial potentials. They are formed from the natural refolding of water-soluble fibroins with alpha-helical and random coil structures in silk glands into insoluble fibers with mainly beta-structures. The structures of the fibroins at atomic resolution and silk formation mechanism remain largely unknown. Here, we report the 3D structures of individual domains of a approximately 366-kDa eggcase silk protein that consists of 20 identical type 1 repetitive domains, one type 2 repetitive domain, and conserved nonrepetitive N- and C-terminal domains. The structures of the individual domains in solution were determined by using NMR techniques. The domain interactions were investigated by NMR and dynamic light-scattering techniques. The formation of micelles and macroscopic fibers from the domains was examined by electron microscopy. We find that either of the terminal domains covalently linked with at least one repetitive domain spontaneously forms micelle-like structures and can be further transformed into fibers at > or = 37 degrees C and a protein concentration of > 0.1 wt%. Our biophysical and biochemical experiments indicate that the less hydrophilic terminal domains initiate the assembly of the proteins and form the outer layer of the micelles whereas the more hydrophilic repetitive domains are embedded inside to ensure the formation of the micelle-like structures that are the essential intermediates in silk formation. Our results establish the roles of individual silk protein domains in fiber formation and provide the basis for designing miniature fibroins for producing artificial silks.

Lin Z; Huang W; Zhang J; Fan JS; Yang D

2009-06-01

269

Solution structure of eggcase silk protein and its implications for silk fiber formation.  

Science.gov (United States)

Spider silks are renowned for their excellent mechanical properties and biomimetic and industrial potentials. They are formed from the natural refolding of water-soluble fibroins with alpha-helical and random coil structures in silk glands into insoluble fibers with mainly beta-structures. The structures of the fibroins at atomic resolution and silk formation mechanism remain largely unknown. Here, we report the 3D structures of individual domains of a approximately 366-kDa eggcase silk protein that consists of 20 identical type 1 repetitive domains, one type 2 repetitive domain, and conserved nonrepetitive N- and C-terminal domains. The structures of the individual domains in solution were determined by using NMR techniques. The domain interactions were investigated by NMR and dynamic light-scattering techniques. The formation of micelles and macroscopic fibers from the domains was examined by electron microscopy. We find that either of the terminal domains covalently linked with at least one repetitive domain spontaneously forms micelle-like structures and can be further transformed into fibers at > or = 37 degrees C and a protein concentration of > 0.1 wt%. Our biophysical and biochemical experiments indicate that the less hydrophilic terminal domains initiate the assembly of the proteins and form the outer layer of the micelles whereas the more hydrophilic repetitive domains are embedded inside to ensure the formation of the micelle-like structures that are the essential intermediates in silk formation. Our results establish the roles of individual silk protein domains in fiber formation and provide the basis for designing miniature fibroins for producing artificial silks. PMID:19458259

Lin, Zhi; Huang, Weidong; Zhang, Jingfeng; Fan, Jing-Song; Yang, Daiwen

2009-05-20

270

Amperometric biosensor based on tyrosinase immobilized onto multiwalled carbon nanotubes-cobalt phthalocyanine-silk fibroin film and its application to determine bisphenol A  

Energy Technology Data Exchange (ETDEWEB)

An amperometric bisphenol A (BPA) biosensor was fabricated by immobilizing tyrosinase on multiwalled carbon nanotubes (MWNTs)-cobalt phthalocyanine (CoPc)-silk fibroin (SF) composite modified glassy carbon electrode (GCE). In MWNTs-CoPc-SF composite film, SF provided a biocompatible microenvironment for the tyrosinase to retain its bioactivity, MWNTs possessed excellent inherent conductivity to enhance the electron transfer rate and CoPc showed good electrocatalytic activity to electrooxidation of BPA. The cyclic voltammogram of BPA at this biosensor exhibited a well defined anodic peak at 0.625 V. Compared with bare GCE, the oxidation signal of BPA significantly increased; therefore, this oxidation signal was used to determine BPA. The effect factors were optimized and the electrochemical parameters were calculated. The possible oxidation mechanism was also discussed. Under optimum conditions, the oxidation current was proportional to BPA concentration in the range from 5.0 x 10{sup -8} to 3.0 x 10{sup -6} M with correlation coefficient of 0.9979 and detection limit of 3.0 x 10{sup -8} M (S/N = 3). The proposed method was successfully applied to determine BPA in plastic products and the recovery was in the range from 95.36% to 104.39%.

Yin Huanshun [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); College of Resources and Environment, Shandong Agricultural University, Taian 271018, Shandong (China); Zhou Yunlei; Xu Jing [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); Ai Shiyun, E-mail: ashy@sdau.edu.cn [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); Cui Lin [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); Zhu Lusheng, E-mail: lushzhu@sdau.edu.cn [College of Resources and Environment, Shandong Agricultural University, Taian 271018, Shandong (China)

2010-02-05

271

The development of silk fibroin scaffolds using an indirect rapid prototyping approach: morphological analysis and cell growth monitoring by spectral-domain optical coherence tomography.  

UK PubMed Central (United Kingdom)

To date, naturally derived biomaterials are rarely used in advanced tissue engineering (TE) methods despite their superior biocompatibility. This is because these native materials, which consist mainly of proteins and polysaccharides, do not possess the ability to withstand harsh processing conditions. Unlike synthetic polymers, natural materials degrade and decompose rapidly in the presence of chemical solvents and high temperature, respectively. Thus, the fabrication of tissue scaffolds using natural biomaterials is often carried out using conventional techniques, where the efficiency in mass transport of nutrients and removal of waste products within the construct is compromised. The present study identified silk fibroin (SF) protein as a suitable material for the application of rapid prototyping (RP) or additive manufacturing (AM) technology. Using the indirect RP method, via the use of a mould, SF tissue scaffolds with both macro- and micro-morphological features can be produced and qualitatively examined by spectral-domain optical coherence tomography (SD-OCT). The advanced imaging technique showed the ability to differentiate the cells and SF material by producing high contrasting images, therefore suggesting the method as a feasible alternative to the histological analysis of cell growth within tissue scaffolds.

Liu MJ; Chou SM; Chua CK; Tay BC; Ng BK

2013-02-01

272

Amperometric biosensor based on tyrosinase immobilized onto multiwalled carbon nanotubes-cobalt phthalocyanine-silk fibroin film and its application to determine bisphenol A  

International Nuclear Information System (INIS)

[en] An amperometric bisphenol A (BPA) biosensor was fabricated by immobilizing tyrosinase on multiwalled carbon nanotubes (MWNTs)-cobalt phthalocyanine (CoPc)-silk fibroin (SF) composite modified glassy carbon electrode (GCE). In MWNTs-CoPc-SF composite film, SF provided a biocompatible microenvironment for the tyrosinase to retain its bioactivity, MWNTs possessed excellent inherent conductivity to enhance the electron transfer rate and CoPc showed good electrocatalytic activity to electrooxidation of BPA. The cyclic voltammogram of BPA at this biosensor exhibited a well defined anodic peak at 0.625 V. Compared with bare GCE, the oxidation signal of BPA significantly increased; therefore, this oxidation signal was used to determine BPA. The effect factors were optimized and the electrochemical parameters were calculated. The possible oxidation mechanism was also discussed. Under optimum conditions, the oxidation current was proportional to BPA concentration in the range from 5.0 x 10-8 to 3.0 x 10-6 M with correlation coefficient of 0.9979 and detection limit of 3.0 x 10-8 M (S/N = 3). The proposed method was successfully applied to determine BPA in plastic products and the recovery was in the range from 95.36% to 104.39%.

2010-02-05

273

Change in silk protein by radiation  

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-03-01

274

A histochemical study of the posterior silk glands of Bombyx mori during metamorphosis from larvae to pupae using frozen sections.  

UK PubMed Central (United Kingdom)

The fine structures of the whole bodies and the posterior silk glands of Bombyx mori during metamorphosis from larvae to pupae in the cocoon were preserved virtually without damage when frozen sections were prepared using an adhesive plastic film. We used frozen sections for histochemical and enzyme histochemistry to characterize the metamorphosis of the posterior silk glands. Frozen sections were stained with DAPI to observe nuclear changes, examined using the TUNEL method to detect DNA fragments, and investigated using in situ hybridization to detect B. mori caspase expression. Both DNA fragments and expression of B. mori caspase increased with progressing metamorphosis. The degeneration of the posterior silk gland during metamorphosis appears to be an apoptotic event.

Kawamoto K; Kawamoto T; Shiba H; Hosono K

2013-09-01

275

The fixation effect of a silk fibroin-bacterial cellulose composite plate in segmental defects of the zygomatic arch: an experimental study.  

UK PubMed Central (United Kingdom)

IMPORTANCE: Bioresorbable fixation systems have been popular for the treatment of facial fractures. However, their mechanical properties are uncertain and complications have been reported. To overcome these problems, we developed a bioresorbable fixation plate using a composite of silk fibroin and bacterial cellulose (SF-BC) with biodegradability and increased biocompatibility. OBJECTIVE: To investigate the regenerative effect of the bioresorbable SF-BC fixation plate on zygomatic arch defects in rats. DESIGN: In vivo animal study. The SF-BC composite plate had a tensile strength similar to that of a polylactic acid plate and a tight, pore-free microstructure. Bilateral segmental bone defects (2 mm in length) were created in the zygomatic arches of adult rats. One side was fixed with the SF-BC composite plate, and the other side was left without fixation. SETTING: Academic research laboratory. PARTICIPANTS: Fifteen adult Sprague-Dawley rats. INTERVENTIONS: Fixation of the zygomatic arch defect with the SF-BC composite plate. MAIN OUTCOMES AND MEASURES: Micro-computed tomography and histological evaluation of bone samples. RESULTS: Gross inspection revealed no specific complication. At 1, 2, 4, and 8 postoperative weeks, the zygomatic arches were explored by micro-computed tomography and histological examination. Control sides did not heal completely and showed bony degeneration and necrosis during the 8-week follow-up. However, we observed new bone formation in sides treated with the SF-BC composite plate, and bony defects were completely healed within 8 weeks. CONCLUSIONS AND RELEVANCE: The SF-BC composite plate is a potential candidate for a new bioresorbable fixation system. Our composite material could considerably shorten bone regeneration time. Additional study of the control of biodegradability and mechanical properties of SF-BC composite plates and a comparative study with the resorbable plates currently in use should be undertaken.

Lee JM; Kim JH; Lee OJ; Park CH

2013-06-01

276

Novel genes differentially expressed between posterior and median silk gland identified by SAGE-aided transcriptome analysis.  

UK PubMed Central (United Kingdom)

Serial analysis of gene expression (SAGE) profiles, from posterior and median cells of the silk gland of Bombyx mori, were analyzed and compared, so as to identify their respective distinguishing functions. The annotation of the SAGE libraries was performed with a B. mori reference tag collection, which was extracted from a novel set of Bombyx ESTs, sequenced from the 3' side. Most of the tags appeared at similar relative concentration within the two libraries, and corresponded with region-specific and highly abundant silk proteins. Strikingly, in addition to tags from silk protein mRNAs, 19 abundant tags were found (? 0.1%), in the median cell library, which were absent in the posterior cell tag collection. With the exception of tags from SP1 mRNA, no PSG specific tags were found in this subset class. The analysis of some of the MSG-specific transcripts, suggested that middle silk gland cells have diversified functions, in addition to their well characterized role in silk sericins synthesis and secretion.

Royer C; Briolay J; Garel A; Brouilly P; Sasanuma S; Sasanuma M; Shimomura M; Keime C; Gandrillon O; Huang Y; Chavancy G; Mita K; Couble P

2011-02-01

277

An Australian webspinner species makes the finest known insect silk fibers  

Energy Technology Data Exchange (ETDEWEB)

Aposthonia gurneyi, an Australian webspinner species, is a primitive insect that constructs and lives in a silken tunnel which screens it from the attentions of predators. The insect spins silk threads from many tiny spines on its forelegs to weave a filmy sheet. We found that the webspinner silk fibers have a mean diameter of only 65 nm, an order of magnitude smaller than any previously reported insect silk. The purpose of such fine silk may be to reduce the metabolic cost of building the extensive tunnels. At the molecular level, the A. gurneyi silk has a predominantly beta-sheet protein structure. The most abundant clone in a cDNA library produced from the webspinner silk glands encoded a protein with extensive glycine-serine repeat regions. The GSGSGS repeat motif of the A. gurneyi silk protein is similar to the well-known GAGAGS repeat motif found in the heavy fibroin of silkworm silk, which also has beta-sheet structure. As the webspinner silk gene is unrelated to the silk gene of the phylogenetically distant silkworm, this is a striking example of convergent evolution.

Okada, Shoko; Weisman, Sarah; Trueman, Holly E.; Mudie, Stephen T.; Haritos, Victoria S.; Sutherland, Tara D. (CSIRO/MSE); (CSIRO)

2009-01-15

278

Cre-mediated targeted gene activation in the middle silk glands of transgenic silkworms (Bombyx mori).  

UK PubMed Central (United Kingdom)

Cre-mediated recombination is widely used to manipulate defined genes spatiotemporally in vivo. The present study evaluated the Cre/loxP system in Bombyx mori by establishing two transgenic lines. One line contained a Cre recombinase gene controlled by a sericin-1 gene (Ser1) promoter. The other line contained a loxP-Stop-loxP-DsRed cassette driven by the same Ser1 promoter. The precise deletion of the Stop fragment was found to be triggered by Cre-mediated site-specific excision, and led to the expression of DsRed fluorescence protein in the middle silk glands of all double-transgenic hybrids. This result was also confirmed by phenotypical analysis. Hence, the current study demonstrated the feasibility of Cre-mediated site-specific recombination in B. mori, and opened a new window for further refining genetic tools in silkworms.

Duan J; Xu H; Ma S; Guo H; Wang F; Zhao P; Xia Q

2013-06-01

279

Production of an active feline interferon in the cocoon of transgenic silkworms using the fibroin H-chain expression system  

International Nuclear Information System (INIS)

We constructed the fibroin H-chain expression system to produce recombinant proteins in the cocoon of transgenic silkworms. Feline interferon (FeIFN) was used for production and to assess the quality of the product. Two types of FeIFN fusion protein, each with N- and C-terminal sequences of the fibroin H-chain, were designed to be secreted into the lumen of the posterior silk glands. The expression of the FeIFN/H-chain fusion gene was regulated by the fibroin H-chain promoter domain. The transgenic silkworms introduced these constructs with the piggyBac transposon-derived vector, which produced the normal sized cocoons containing each FeIFN/H-chain fusion protein. Although the native-protein produced by transgenic silkworms have almost no antiviral activity, the proteins after the treatment with PreScission protease to eliminate fibroin H-chain derived N- and C-terminal sequences from the products, had very high antiviral activity. This H-chain expression system, using transgenic silkworms, could be an alternative method to produce an active recombinant protein and silk-based biomaterials.

2007-04-20

280

Histochemical and ultrastructural evidence of lipid secretion by the silk gland of the sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) Evidências histoquímicas e ultra-estruturais de secreção sipídica pela glândula da seda da broca da cana-de-açúcar, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae)  

Directory of Open Access Journals (Sweden)

Full Text Available The silk gland in Lepidoptera larvae is responsible for the silk production used for shelter or cocoon construction. The secretion of fibroin and sericin by the different silk gland regions are well established. There are few attempts to detect lipid components in the insect silk secretion, although the presence of such element may contribute to the resistance of the shelter to wet environment. This study characterizes the glandular region and detects the presence of lipid components in the secretion of the silk gland of Diatraea saccharalis(Fabricius). The silk gland was submitted to histochemical procedure for lipid detection or conventionally prepared for ultrastructural analyses. Lipid droplets were histochemically detected in both the apical cytoplasm of cell of the anterior region and in the lumen among the microvilli. Ultrastructural analyses of the anterior region showed lipid material, visualized as myelin-like structures within the vesicular Golgi complex and in the apical secretory globules, mixed up with the sericin; similar material was observed into the lumen, adjacent to the microvilli. Lipids were not detected in the cells neither in the lumen of the posterior region. Our results suggest that the silk produced by D. saccharalis has a minor lipid content that is secreted by the anterior region together with the sericin.A glândula da seda de larvas de Lepidoptera é responsável pela produção da seda usada na construção do casulo ou do abrigo. A secreção de fibroína e sericina pelas diferentes regiões da glândula da seda está bem estabelecida. Existem poucos trabalhos tentando identificar componentes lipídicos na secreção de seda de insetos, embora a presença desse componente contribua para a resistência da seda a ambiente úmidos. Este estudo teve como objetivo identificar a presença de componente lipídico na secreção da glândula da seda de larvas de Diatraea saccharalis (Fabricius), bem como caracterizar a região glandular responsável pela secreção. A glândula da seda foi submetida a procedimentos histoquímicos para detecção de lipídeos e convencionalmente preparada para análise ultra-estrutural. Gotas lipídicas foram histoquimicamente detectadas no citoplasma apical de células da região anterior e no lúmen, entre os microvilos. A análise ultra-estrutural da região anterior mostrou material lipídico, visualizado como figuras do tipo mielina dentro do complexo de Golgi vesicular e nos glóbulos secretores apicais, misturados com sericina; material semelhante foi observado dentro do lúmen, adjacente aos microvilos. Nenhum componente secretor lipídico foi detectado nas células ou no lúmen da região posterior. Os resultados sugerem que a seda produzida pela D. saccharalis tem, pelo menos, um discreto componente lipídico, que é secretado pela região anterior, junto com a sericina.

Eliane Victoriano; Daniela O. Pinheiro; Elisa A. Gregório

2007-01-01

 
 
 
 
281

Histochemical and ultrastructural evidence of lipid secretion by the silk gland of the sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae)/ Evidências histoquímicas e ultra-estruturais de secreção sipídica pela glândula da seda da broca da cana-de-açúcar, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae)  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A glândula da seda de larvas de Lepidoptera é responsável pela produção da seda usada na construção do casulo ou do abrigo. A secreção de fibroína e sericina pelas diferentes regiões da glândula da seda está bem estabelecida. Existem poucos trabalhos tentando identificar componentes lipídicos na secreção de seda de insetos, embora a presença desse componente contribua para a resistência da seda a ambiente úmidos. Este estudo teve como objetivo identific (more) ar a presença de componente lipídico na secreção da glândula da seda de larvas de Diatraea saccharalis (Fabricius), bem como caracterizar a região glandular responsável pela secreção. A glândula da seda foi submetida a procedimentos histoquímicos para detecção de lipídeos e convencionalmente preparada para análise ultra-estrutural. Gotas lipídicas foram histoquimicamente detectadas no citoplasma apical de células da região anterior e no lúmen, entre os microvilos. A análise ultra-estrutural da região anterior mostrou material lipídico, visualizado como figuras do tipo mielina dentro do complexo de Golgi vesicular e nos glóbulos secretores apicais, misturados com sericina; material semelhante foi observado dentro do lúmen, adjacente aos microvilos. Nenhum componente secretor lipídico foi detectado nas células ou no lúmen da região posterior. Os resultados sugerem que a seda produzida pela D. saccharalis tem, pelo menos, um discreto componente lipídico, que é secretado pela região anterior, junto com a sericina. Abstract in english The silk gland in Lepidoptera larvae is responsible for the silk production used for shelter or cocoon construction. The secretion of fibroin and sericin by the different silk gland regions are well established. There are few attempts to detect lipid components in the insect silk secretion, although the presence of such element may contribute to the resistance of the shelter to wet environment. This study characterizes the glandular region and detects the presence of lipi (more) d components in the secretion of the silk gland of Diatraea saccharalis(Fabricius). The silk gland was submitted to histochemical procedure for lipid detection or conventionally prepared for ultrastructural analyses. Lipid droplets were histochemically detected in both the apical cytoplasm of cell of the anterior region and in the lumen among the microvilli. Ultrastructural analyses of the anterior region showed lipid material, visualized as myelin-like structures within the vesicular Golgi complex and in the apical secretory globules, mixed up with the sericin; similar material was observed into the lumen, adjacent to the microvilli. Lipids were not detected in the cells neither in the lumen of the posterior region. Our results suggest that the silk produced by D. saccharalis has a minor lipid content that is secreted by the anterior region together with the sericin.

Victoriano, Eliane; Pinheiro, Daniela O.; Gregório, Elisa A.

2007-10-01

282

Involvement of cathepsin B- and L-like proteinases in silk gland histolysis during metamorphosis of Bombyx mori.  

UK PubMed Central (United Kingdom)

To identify proteinases involved in programmed cell death of the silk glands of Bombyx mori, we measured enzyme activities in silk gland homogenates. Several peptidyl-4-methylcoumaryl-7-amides (MCAs) and bovine hemoglobin were used as substrates in the presence and absence of proteinase inhibitors. The hydrolysis of t-butyloxycarbonyl-Phe-Ser-Arg-MCA (Boc-FSR-MCA), benzyloxy-carbonyl-Phe-Arg-MCA (Z-FR-MCA), and Z-Arg-Arg-MCA (Z-RR-MCA) was optimal at pH 5.5, 5.0, and 5.5, respectively. It was stimulated by the sulfhydryl compounds or EDTA and inhibited by both cysteine proteinase inhibitors and a cathepsin B-specific inhibitor, l-3-trans-(propyl-carbamoyl)oxirane-2-carbonyl)-L-isoleucyl-L-prolin (CA-074). The hemoglobin hydrolysis at the optimum pH 3.5 was inactivated by cysteine proteinase inhibitors, but stimulated slightly by pepstatin. The cleavage of Arg-MCA (R-MCA) and Leu-MCA (L-MCA) at optimum pH of 7.0 was strongly inhibited by an aminopeptidase inhibitor, puromycin, and by sulfhydryl compounds. The Boc-FSR-MCA, Z-FR-MCA, Z-RR-MCA, and hemoglobin hydrolyzing activities increased in the silk glands dramatically after cocoon formation, while the R-MCA and L-MCA cleaving activities declined. The results strongly suggest the involvement of cathepsin B- and cathepsin L-like proteinases in the histolysis of the silk gland during metamorphosis.

Shiba H; Uchida D; Kobayashi H; Natori M

2001-06-01

283

Involvement of cathepsin B- and L-like proteinases in silk gland histolysis during metamorphosis of Bombyx mori.  

Science.gov (United States)

To identify proteinases involved in programmed cell death of the silk glands of Bombyx mori, we measured enzyme activities in silk gland homogenates. Several peptidyl-4-methylcoumaryl-7-amides (MCAs) and bovine hemoglobin were used as substrates in the presence and absence of proteinase inhibitors. The hydrolysis of t-butyloxycarbonyl-Phe-Ser-Arg-MCA (Boc-FSR-MCA), benzyloxy-carbonyl-Phe-Arg-MCA (Z-FR-MCA), and Z-Arg-Arg-MCA (Z-RR-MCA) was optimal at pH 5.5, 5.0, and 5.5, respectively. It was stimulated by the sulfhydryl compounds or EDTA and inhibited by both cysteine proteinase inhibitors and a cathepsin B-specific inhibitor, l-3-trans-(propyl-carbamoyl)oxirane-2-carbonyl)-L-isoleucyl-L-prolin (CA-074). The hemoglobin hydrolysis at the optimum pH 3.5 was inactivated by cysteine proteinase inhibitors, but stimulated slightly by pepstatin. The cleavage of Arg-MCA (R-MCA) and Leu-MCA (L-MCA) at optimum pH of 7.0 was strongly inhibited by an aminopeptidase inhibitor, puromycin, and by sulfhydryl compounds. The Boc-FSR-MCA, Z-FR-MCA, Z-RR-MCA, and hemoglobin hydrolyzing activities increased in the silk glands dramatically after cocoon formation, while the R-MCA and L-MCA cleaving activities declined. The results strongly suggest the involvement of cathepsin B- and cathepsin L-like proteinases in the histolysis of the silk gland during metamorphosis. PMID:11368511

Shiba, H; Uchida, D; Kobayashi, H; Natori, M

2001-06-01

284

Hormonal regulation of the death commitment in programmed cell death of the silkworm anterior silk glands.  

UK PubMed Central (United Kingdom)

During larval-pupal transformation, the anterior silk glands (ASGs) of the silkworm Bombyx mori undergo programmed cell death (PCD) triggered by 20-hydroxyecdysone (20E). Under standard in vitro culture conditions (0.3 ml of medium with 1 ?M 20E), ASGs of the fourth-instar larvae do not undergo PCD in response to 20E. Similarly, larvae of the fifth instar do not respond to 20E through day 5 of the instar (V5). However, ASGs of V6 die when challenged by 20E, indicating that the glands might be destined to die before V6 but that a death commitment is not yet present. When we increased the volume of culture medium for one gland from 0.3 to 9 ml, V5 ASGs underwent PCD. We examined the response of ASGs to 20E every day by culturing them in 9 ml of medium and found that ASGs on and after V2 were fully responsive to 20E. Because pupal commitment is associated with juvenile hormone (JH), the corpora allata (a JH secretory organ) were removed on day 3 of the fourth larval instar (IV3), and their ASGs on V0 were cultured with 20E. Removal of the corpora allata allowed the V0 larval ASGs to respond to 20E with PCD. In contrast, topical application of a JH analogue inhibited the response to 20E when applied on or before V5. We conclude that the acquisition of responsiveness to 20E precedes the loss of JH sensitivity, and that the death commitment in ASGs occurs between V5 and 6.

Matsui H; Kakei M; Iwami M; Sakurai S

2012-12-01

285

Characterization of fibroin and PEG-blended fibroin matrices for in vitro adhesion and proliferation of osteoblasts.  

UK PubMed Central (United Kingdom)

Silk fibroin protein, isolated from cocoons of the domesticated mulberry silkworm, Bombyx mori, finds extensive application in biomaterial design. In this study, poly(ethylene glycol) (PEG) 4000 has been used for blending fibroin from both B. mori and Antheraea mylitta, the wild tropical non-mulberry silkworm. PEG-blended films have shown marked changes from the pure fibroin films with respect to thermal properties and mechanical properties. FT-IR spectroscopy confirmed incorporation of new functional groups like quinone oximes. Pure fibroin and PEG-blended fibroin films showed biocompatibility with the HOS osteosarcoma cell line. Von Kossa staining confirmed nodule formation due to mineralization and differentiation of osteoblasts on pure and blended matrices. On account of increased surface roughness, higher elongation percentage, higher thermostability and better activity of osteoblasts in terms of intracellular alkaline phosphatase production, PEG-blended A. mylitta fibroin film shows better potential than PEG-blended B. mori fibroin film for use as potential biomaterial.

Acharya C; Kumary TV; Ghosh SK; Kundu SC

2009-01-01

286

Synthetic spider silk fibers spun from Pyriform Spidroin 2, a glue silk protein discovered in orb-weaving spider attachment discs.  

UK PubMed Central (United Kingdom)

Spider attachment disc silk fibers are spun into a viscous liquid that rapidly solidifies, gluing dragline silk fibers to substrates for locomotion or web construction. Here we report the identification and artificial spinning of a novel attachment disc glue silk fibroin, Pyriform Spidroin 2 (PySp2), from the golden orb weaver Nephila clavipes . MS studies support PySp2 is a constituent of the pyriform gland that is spun into attachment discs. Analysis of the PySp2 protein architecture reveals sequence divergence relative to the other silk family members, including the cob weaver glue silk fibroin PySp1. PySp2 contains internal block repeats that consist of two subrepeat units: one dominated by Ser, Gln, and Ala and the other Pro-rich. Artificial spinning of recombinant PySp2 truncations shows that the Ser-Gln-Ala-rich subrepeat is sufficient for the assembly of polymeric subunits and subsequent fiber formation. These studies support that both orb- and cob-weaving spiders have evolved highly polar block-repeat sequences with the ability to self-assemble into fibers, suggesting a strategy to allow fiber fabrication in the liquid environment of the attachment discs.

Geurts P; Zhao L; Hsia Y; Gnesa E; Tang S; Jeffery F; La Mattina C; Franz A; Larkin L; Vierra C

2010-12-01

287

Synthetic spider silk fibers spun from Pyriform Spidroin 2, a glue silk protein discovered in orb-weaving spider attachment discs.  

Science.gov (United States)

Spider attachment disc silk fibers are spun into a viscous liquid that rapidly solidifies, gluing dragline silk fibers to substrates for locomotion or web construction. Here we report the identification and artificial spinning of a novel attachment disc glue silk fibroin, Pyriform Spidroin 2 (PySp2), from the golden orb weaver Nephila clavipes . MS studies support PySp2 is a constituent of the pyriform gland that is spun into attachment discs. Analysis of the PySp2 protein architecture reveals sequence divergence relative to the other silk family members, including the cob weaver glue silk fibroin PySp1. PySp2 contains internal block repeats that consist of two subrepeat units: one dominated by Ser, Gln, and Ala and the other Pro-rich. Artificial spinning of recombinant PySp2 truncations shows that the Ser-Gln-Ala-rich subrepeat is sufficient for the assembly of polymeric subunits and subsequent fiber formation. These studies support that both orb- and cob-weaving spiders have evolved highly polar block-repeat sequences with the ability to self-assemble into fibers, suggesting a strategy to allow fiber fabrication in the liquid environment of the attachment discs. PMID:21053953

Geurts, Paul; Zhao, Liang; Hsia, Yang; Gnesa, Eric; Tang, Simon; Jeffery, Felicia; La Mattina, Coby; Franz, Andreas; Larkin, Leah; Vierra, Craig

2010-11-05

288

Analysis of Transcripts Expressed in One-Day-Old Larvae and Fifth Instar Silk Glands of Tasar Silkworm, Antheraea mylitta.  

UK PubMed Central (United Kingdom)

Antheraea mylitta is one of the wild nonmulberry silkworms, which produces tasar silk. An EST project has been undertaken to understand the gene expression profile of A. mylitta silk gland. Two cDNA libraries, one from the whole bodies of one-day-old larvae and the other from the silkglands of fifth instar larvae, were constructed and sequenced. A total of 2476 good-quality ESTs (1239 clones) were obtained and grouped into 648 clusters containing 390 contigs and 258 singletons to represent 467 potential unigenes. Forty-five sequences contained putative coding region, and represented potentially novel genes. Among the 648 clusters, 241 were categorized according to Gene Ontology hierarchy and showed presence of several silk and immune-related genes. The A. mylitta ESTs have been organized into a freely available online database "AmyBASE". These data provide an initial insight into the A. mylitta transcriptome and help to understand the molecular mechanism of silk protein production in a Lepidopteran species.

Maity S; Goel SI; Roy S; Ghorai S; Bhattacharyya S; Venugopalan A; Ghosh AK

2010-01-01

289

Analysis of Transcripts Expressed in One-Day-Old Larvae and Fifth Instar Silk Glands of Tasar Silkworm, Antheraea mylitta.  

Science.gov (United States)

Antheraea mylitta is one of the wild nonmulberry silkworms, which produces tasar silk. An EST project has been undertaken to understand the gene expression profile of A. mylitta silk gland. Two cDNA libraries, one from the whole bodies of one-day-old larvae and the other from the silkglands of fifth instar larvae, were constructed and sequenced. A total of 2476 good-quality ESTs (1239 clones) were obtained and grouped into 648 clusters containing 390 contigs and 258 singletons to represent 467 potential unigenes. Forty-five sequences contained putative coding region, and represented potentially novel genes. Among the 648 clusters, 241 were categorized according to Gene Ontology hierarchy and showed presence of several silk and immune-related genes. The A. mylitta ESTs have been organized into a freely available online database "AmyBASE". These data provide an initial insight into the A. mylitta transcriptome and help to understand the molecular mechanism of silk protein production in a Lepidopteran species. PMID:20454581

Maity, Samita; Goel, Sagar I; Roy, Sobhan; Ghorai, Suvankar; Bhattacharyya, Swati; Venugopalan, Aravind; Ghosh, Ananta K

2010-05-04

290

Environmental conditions impinge on dragline silk protein composition.  

Science.gov (United States)

The silk formed in the major ampullate (MA) gland of the orb weaving spider Nephila clavipes is composed of two silk fibroins, which are called major ampullate spidroins 1 (MaSp1) and 2 (MaSp2). Analysis of proteolytic peptides and reactivity to spidroin type specific antibodies indicated that MaSp2 constituted only a minor part in the spinning dope as well as in the spun filaments. Upon starvation, a change in the silk's characteristic features was observed that was concomitant of a decrease in the contribution of MaSp2. The silk became less elastic and stiffer, which will better tailor its usability for the safety line, albeit at the expense of its employment as the web frame threads. In addition, since MaSp2 production requires greater ATP consumption, such a shift in the protein ratio cuts down on the energy costs to produce the silk. From this change in protein composition the spider might therefore benefit twice, by synthesizing 'cheaper' silk that into the bargain has properties that potentially can better support foraging in times of food shortage. PMID:18828841

Guehrs, K-H; Schlott, B; Grosse, F; Weisshart, K

2008-09-01

291

Piriform Spider Silk Sequences Reveal Unique Repetitive Elements.  

UK PubMed Central (United Kingdom)

Orb-weaving spider silk fibers are assembled from very large, highly repetitive proteins. The repeated segments contain, in turn, short, simple, and repetitive amino acid motifs that account for the physical and mechanical properties of the assembled fiber. Of the six orb-weaver silk fibroins, the piriform silk that makes the attachment discs, which lashes the joints of the web and attaches dragline silk to surfaces, has not been previously characterized. Piriform silk protein cDNAs were isolated from phage libraries of three species: A. trifasciata , N. clavipes , and N. cruentata . The deduced amino acid sequences from these genes revealed two new repetitive motifs: an alternating proline motif, where every other amino acid is proline, and a glutamine-rich motif of 6-8 amino acids. Similar to other spider silk proteins, the repeated segments are large (>200 amino acids) and highly homogenized within a species. There is also substantial sequence similarity across the genes from the three species, with particular conservation of the repetitive motifs. Northern blot analysis revealed that the mRNA is larger than 11 kb and is expressed exclusively in the piriform glands of the spider. Phylogenetic analysis of the C-terminal regions of the new proteins with published spidroins robustly shows that the piriform sequences form an ortholog group.

Perry DJ; Bittencourt D; Siltberg-Liberles J; Rech EL; Lewis RV

2010-10-01

292

Piriform Spider Silk Sequences Reveal Unique Repetitive Elements.  

Science.gov (United States)

Orb-weaving spider silk fibers are assembled from very large, highly repetitive proteins. The repeated segments contain, in turn, short, simple, and repetitive amino acid motifs that account for the physical and mechanical properties of the assembled fiber. Of the six orb-weaver silk fibroins, the piriform silk that makes the attachment discs, which lashes the joints of the web and attaches dragline silk to surfaces, has not been previously characterized. Piriform silk protein cDNAs were isolated from phage libraries of three species: A. trifasciata , N. clavipes , and N. cruentata . The deduced amino acid sequences from these genes revealed two new repetitive motifs: an alternating proline motif, where every other amino acid is proline, and a glutamine-rich motif of 6-8 amino acids. Similar to other spider silk proteins, the repeated segments are large (>200 amino acids) and highly homogenized within a species. There is also substantial sequence similarity across the genes from the three species, with particular conservation of the repetitive motifs. Northern blot analysis revealed that the mRNA is larger than 11 kb and is expressed exclusively in the piriform glands of the spider. Phylogenetic analysis of the C-terminal regions of the new proteins with published spidroins robustly shows that the piriform sequences form an ortholog group. PMID:20954740

Perry, David J; Bittencourt, Daniela; Siltberg-Liberles, Jessica; Rech, Elibio L; Lewis, Randolph V

2010-10-18

293

Silk Thread Containing Spider Thread Protein and Silk Worm Producing the Silk Thread  

UK PubMed Central (United Kingdom)

A transgenic silkworm having transferred therein a gene which encodes spider thread protein having desired properties of high strength and high elasticity while leaving the silkworm fibroin H chain gene intact, by means of utilizing a transposon function, is used to produce in the transgenic silkworm a spider thread protein having the desired properties without lowering the strength or elasticity of silk thread produced by the transgenic silkworm, thereby providing hybrid silk of spider and silk threads having the desired properties.

HIRAMATSU SHINGO; MORIYAMA HIROMITSU; ASAOKA RYOTA; MORITA KEN; TANAKA TAKASHI; YAMADA KATSUSHIGE; OBRIEN JOHN PHILIP; FAHNESTOCK STEPHEN R

294

Radiation degradation of silk protein  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-09-01

295

Radiation degradation of silk protein  

Energy Technology Data Exchange (ETDEWEB)

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)

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

296

Pyriform spidroin 1, a novel member of the silk gene family that anchors dragline silk fibers in attachment discs of the black widow spider, Latrodectus hesperus.  

UK PubMed Central (United Kingdom)

Spiders spin high performance threads that have diverse mechanical properties for specific biological applications. To better understand the molecular mechanism by which spiders anchor their threads to a solid support, we solubilized the attachment discs from black widow spiders and performed in-solution tryptic digests followed by MS/MS analysis to identify novel peptides derived from glue silks. Combining matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry and cDNA library screening, we isolated a novel member of the silk gene family called pysp1 and demonstrate that its protein product is assembled into the attachment disc silks. Alignment of the PySp1 amino acid sequence to other fibroins revealed conservation in the non-repetitive C-terminal region of the silk family. MS/MS analysis also confirmed the presence of MaSp1 and MaSp2, two important components of dragline silks, anchored within the attachment disc materials. Characterization of the ultrastructure of attachment discs using scanning electron microscopy studies support the localization of PySp1 to small diameter fibers embedded in a glue-like cement, which network with large diameter dragline silk threads, producing a strong, adhesive material. Consistent with elevated PySp1 mRNA levels detected in the pyriform gland, MS analysis of the luminal contents extracted from the pyriform gland after tryptic digestion support the assertion that PySp1 represents one of the major constituents manufactured in the pyriform gland. Taken together, our data demonstrate that PySp1 is spun into attachment disc silks to help affix dragline fibers to substrates, a critical function during spider web construction for prey capture and locomotion.

Blasingame E; Tuton-Blasingame T; Larkin L; Falick AM; Zhao L; Fong J; Vaidyanathan V; Visperas A; Geurts P; Hu X; La Mattina C; Vierra C

2009-10-01

297

Pyriform spidroin 1, a novel member of the silk gene family that anchors dragline silk fibers in attachment discs of the black widow spider, Latrodectus hesperus.  

Science.gov (United States)

Spiders spin high performance threads that have diverse mechanical properties for specific biological applications. To better understand the molecular mechanism by which spiders anchor their threads to a solid support, we solubilized the attachment discs from black widow spiders and performed in-solution tryptic digests followed by MS/MS analysis to identify novel peptides derived from glue silks. Combining matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry and cDNA library screening, we isolated a novel member of the silk gene family called pysp1 and demonstrate that its protein product is assembled into the attachment disc silks. Alignment of the PySp1 amino acid sequence to other fibroins revealed conservation in the non-repetitive C-terminal region of the silk family. MS/MS analysis also confirmed the presence of MaSp1 and MaSp2, two important components of dragline silks, anchored within the attachment disc materials. Characterization of the ultrastructure of attachment discs using scanning electron microscopy studies support the localization of PySp1 to small diameter fibers embedded in a glue-like cement, which network with large diameter dragline silk threads, producing a strong, adhesive material. Consistent with elevated PySp1 mRNA levels detected in the pyriform gland, MS analysis of the luminal contents extracted from the pyriform gland after tryptic digestion support the assertion that PySp1 represents one of the major constituents manufactured in the pyriform gland. Taken together, our data demonstrate that PySp1 is spun into attachment disc silks to help affix dragline fibers to substrates, a critical function during spider web construction for prey capture and locomotion. PMID:19666476

Blasingame, Eric; Tuton-Blasingame, Tiffany; Larkin, Leah; Falick, Arnold M; Zhao, Liang; Fong, Justine; Vaidyanathan, Veena; Visperas, Anabelle; Geurts, Paul; Hu, Xiaoyi; La Mattina, Coby; Vierra, Craig

2009-08-07

298

Hierarchical biomineralization of calcium carbonate regulated by silk microspheres.  

UK PubMed Central (United Kingdom)

As an analog of the main protein contained in nacre regenerated Bombyx mori silk fibroin has a significant influence on the morphology and polymorphic nature of CaCO3 in the biomineralization process. A number of studies have implied that the self-assembling aggregate structure of silk fibroin is a key factor in controlling CaCO3 aggregation. Further insight into this role is necessary with a particular need to prepare silk fibroin aggregates with homogeneous structures to serve as templates for the mineralization process. Here we have prepared homogeneous silk microspheres to serve as templates for CaCO3 mineralization in order to provide an experimental insight into silk-regulated crystallization processes. CaCO3 particles with different nano- and microstructures, and their polymorphs, were successfully formed by controlling the mineralization process. The key function of silk aggregation in controlling the morphology and polymorphic nature of CaCO3 particles was confirmed. A regulating effect of silk on the spatial features was also observed. A two-step process for silk fibroin-regulated biomineralization was found, with different levels of heterogeneous nucleation and aggregation. A full understanding of silk fibroin-regulated biomineralization mechanisms would help in understanding the function of organic polymers in natural biomineralization, and provide a way forward in the design and synthesis of new materials in which organic-inorganic interfaces are the keys to function, biological interfaces and many related material features.

Zhang X; Fan Z; Lu Q; Huang Y; Kaplan DL; Zhu H

2013-06-01

299

Hierarchical biomineralization of calcium carbonate regulated by silk microspheres.  

Science.gov (United States)

As an analog of the main protein contained in nacre regenerated Bombyx mori silk fibroin has a significant influence on the morphology and polymorphic nature of CaCO3 in the biomineralization process. A number of studies have implied that the self-assembling aggregate structure of silk fibroin is a key factor in controlling CaCO3 aggregation. Further insight into this role is necessary with a particular need to prepare silk fibroin aggregates with homogeneous structures to serve as templates for the mineralization process. Here we have prepared homogeneous silk microspheres to serve as templates for CaCO3 mineralization in order to provide an experimental insight into silk-regulated crystallization processes. CaCO3 particles with different nano- and microstructures, and their polymorphs, were successfully formed by controlling the mineralization process. The key function of silk aggregation in controlling the morphology and polymorphic nature of CaCO3 particles was confirmed. A regulating effect of silk on the spatial features was also observed. A two-step process for silk fibroin-regulated biomineralization was found, with different levels of heterogeneous nucleation and aggregation. A full understanding of silk fibroin-regulated biomineralization mechanisms would help in understanding the function of organic polymers in natural biomineralization, and provide a way forward in the design and synthesis of new materials in which organic-inorganic interfaces are the keys to function, biological interfaces and many related material features. PMID:23518477

Zhang, Xiuli; Fan, Zhihai; Lu, Qiang; Huang, Yongli; Kaplan, David L; Zhu, Hesun

2013-03-19

300

Fibroin and fibroin blended three-dimensional scaffolds for rat chondrocyte culture.  

UK PubMed Central (United Kingdom)

BACKGROUND: In our previous study, we successfully developed 3-D scaffolds prepared from silk fibroin (SF), silk fibroin/collagen (SF/C) and silk fibroin/gelatin (SF/G) using a freeze drying technique. The blended construct showed superior mechanical properties to silk fibroin construct. In addition, collagen and gelatin, contain RGD sequences that could facilitate cell attachment and proliferation. Therefore, in this study, the ability of silk fibroin and blended constructs to promote cell adhesion, proliferation and production of extracellular matrix (EMC) were compared. METHODS: Articular chondrocytes were isolated from rat and cultured on the prepared constructs. Then, the cell viability in SF, SF/C and SF/G scaffolds was determined by MTT assay. Cell morphology and distribution were investigated by scanning electron microscopy (SEM) and histological analysis. Moreover, the secretion of extracellular matrix (ECM) by the chondrocytes in 3-D scaffolds was assessed by immunohistochemistry. RESULTS: Results from MTT assay indicated that the blended SF/C and SF/G scaffolds provided a more favorable environment for chondrocytes attachment and proliferation than that of SF scaffold. In addition, scanning electron micrographs and histological images illustrated higher cell density and distribution in the SF/C and SF/G scaffolds than that in the SF scaffold. Importantly, immunohistochemistry strongly confirmed a greater production of type II collagen and aggrecan, important markers of chondrocytic phenotype, in SF blended scaffolds than that in the SF scaffold. CONCLUSION: Addition of collagen and gelatin to SF solution not only improved the mechanical properties of the scaffolds but also provided an effective biomaterial constructs for chondrocyte growth and chondrocytic phenotype maintenance. Therefore, SF/C and SF/G showed a great potential as a desirable biomaterial for cartilage tissue engineering.

Chomchalao P; Pongcharoen S; Sutheerawattananonda M; Tiyaboonchai W

2013-01-01

 
 
 
 
301

Silver nanoparticles incorporated electrospun silk fibers.  

Science.gov (United States)

We present a simple and mass-producible method of incorporating silver nanoparticles on the surface of electrospun silk non-woven membranes for the fabrication of antimicrobial wound dressings. Nanofibrous silk membranes with fiber diameters of 460 +/- 40 nm were electrospun from an aqueous Bombyx mori fibroin solution. The electrospun membranes incorporating silver nanoparticles were prepared by dipping the membranes in aqueous silver nitrate (AgNO3) solution (0.5 or 1.0 wt%) followed by photoreduction. Field emission scanning and transmission electron microscopy showed that silver nanoparticles were generated on the electrospun silk fibroin nanofibers as well as inside them. The interaction between the silver nanoparticles and amide groups in the silk fibroin molecules was characterized using X-ray photoelectron spectroscopy. PMID:18047081

Kang, Minsung; Jung, Rira; Kim, Hun-Sik; Youk, Ji Ho; Jin, Hyoung-Joon

2007-11-01

302

Silver nanoparticles incorporated electrospun silk fibers.  

UK PubMed Central (United Kingdom)

We present a simple and mass-producible method of incorporating silver nanoparticles on the surface of electrospun silk non-woven membranes for the fabrication of antimicrobial wound dressings. Nanofibrous silk membranes with fiber diameters of 460 +/- 40 nm were electrospun from an aqueous Bombyx mori fibroin solution. The electrospun membranes incorporating silver nanoparticles were prepared by dipping the membranes in aqueous silver nitrate (AgNO3) solution (0.5 or 1.0 wt%) followed by photoreduction. Field emission scanning and transmission electron microscopy showed that silver nanoparticles were generated on the electrospun silk fibroin nanofibers as well as inside them. The interaction between the silver nanoparticles and amide groups in the silk fibroin molecules was characterized using X-ray photoelectron spectroscopy.

Kang M; Jung R; Kim HS; Youk JH; Jin HJ

2007-11-01

303

Ultrastructure of the excretory duct in the silk gland of the sugarcane borer Diatraea saccharalis (Lepidoptera: Pyralidae).  

Science.gov (United States)

The excretory duct in the silk gland of the sugarcane borer Diatraea saccharalis consists of two morphologically distinct regions, recognized by scanning and transmission electron microscopy. The thin posterior region, adjacent to the glandular region, presents a regular surface. Secretory vesicles containing either electron-dense or fibrillar cuticular-like materials are observed in their apical cytoplasm; the same cuticular materials were detected as extracellular deposits among the microvilli. The short anterior region, near the common duct, exhibits surface protrusions; there are no secretory vesicles in their apical cytoplasm. These results show that only the duct cells at the posterior region are involved in the secretion of the cuticular intima elements. Desmosome-like structures were visualized linking together adjacent microvillar membranes only in the cells of anterior duct region, with unknown function. The transition between the duct and the glandular region is abrupt; the cells of the glandular and posterior duct regions present large amounts of microtubules. Nerve fibers can be observed between the duct cells in their two regions, suggesting that control of silk secretion may occur in the excretory duct via neurotransmitter liberation. PMID:18088967

Victoriano, Eliane; Gregório, Elisa A

2002-09-01

304

Ultrastructure of the excretory duct in the silk gland of the sugarcane borer Diatraea saccharalis (Lepidoptera: Pyralidae).  

UK PubMed Central (United Kingdom)

The excretory duct in the silk gland of the sugarcane borer Diatraea saccharalis consists of two morphologically distinct regions, recognized by scanning and transmission electron microscopy. The thin posterior region, adjacent to the glandular region, presents a regular surface. Secretory vesicles containing either electron-dense or fibrillar cuticular-like materials are observed in their apical cytoplasm; the same cuticular materials were detected as extracellular deposits among the microvilli. The short anterior region, near the common duct, exhibits surface protrusions; there are no secretory vesicles in their apical cytoplasm. These results show that only the duct cells at the posterior region are involved in the secretion of the cuticular intima elements. Desmosome-like structures were visualized linking together adjacent microvillar membranes only in the cells of anterior duct region, with unknown function. The transition between the duct and the glandular region is abrupt; the cells of the glandular and posterior duct regions present large amounts of microtubules. Nerve fibers can be observed between the duct cells in their two regions, suggesting that control of silk secretion may occur in the excretory duct via neurotransmitter liberation.

Victoriano E; Gregório EA

2002-09-01

305

Effect of silk protein processing on drug delivery from silk films.  

UK PubMed Central (United Kingdom)

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 degradation of a silk film by protease. Model compounds spanning a range of physical-chemical properties generally show an inverse relationship between degumming time and release rate through a varied degumming time silk coating. Degumming provides a useful control point to manipulate silk's material properties.

Pritchard EM; Hu X; Finley V; Kuo CK; Kaplan DL

2013-03-01

306

SILK THREAD CONTAINING SPIDER THREAD PROTEIN AND SILKWORM PRODUCING THE SILK THREAD  

UK PubMed Central (United Kingdom)

A transgenic silkworm having transferred therein a gene which encodes spider thread protein having desired properties of high strength and high elasticity while leaving the silkworm fibroin H chain gene intact, by means of utilizing a transposon function, is used to produce in the transgenic silkworm a spider thread protein having the desired properties without lowering the strength or elasticity of silk thread produced by the transgenic silkworm, thereby providing hybrid silk of spider and silk threads having the desired properties.

HIRAMATSU Shingo City-Heim 202; MORIYAMA Hiromitsu City-Winds Mizonokuchi; ASAOKA Ryota Toray Dai-ichi Urayasuryo 405; MORITA Ken Lairi ecrin 3B; TANAKA Takashi Atrait Uchidabashi 1101; YAMADA Katsushige; OBRIEN John Philip; FAHNESTOCK Stephen R.

307

SILK THREAD CONTAINING SPIDER THREAD PROTEIN AND SILK WORM PRODUCING THE SILK THREAD  

UK PubMed Central (United Kingdom)

By using a transgenic silkworm having a gene, which encodes a spider thread protein having desired properties (a high strength, a high elongation, etc.), transferred thereinto without injuring silkworm fibroin H-chain gene by a means of, for example, using the transposon function, the spider thread protein having the desired properties is produced by the transgenic silkworm without lowering the strength or elongation of silk thread produced by the transgenic silkworm, thereby providing a hybrid silk of spider thread with silk thread having the desired properties.

HIRAMATSU SHINGO; MORIYAMA HIROMITSU; ASAOKA RYOTA; MORITA KEN; TANAKA TAKASHI; YAMADA KATSUSHIGE; OBRIEN JOHN PHILIP; FAHNESTOCK STEPHEN R

308

Production of fine powder from silk by radiation  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-09-01

309

Negative supercoiling of DNA facilitates an interaction between transcription factor IID and the fibroin gene promoter  

Energy Technology Data Exchange (ETDEWEB)

Transcription of the fibroin gene can be reconstituted with partially purified components from HeLa cells. Transcription factors IIB, IID, and IIE and RNA polymerase II are required for accurate initiation of transcription. Linear and relaxed closed circular DNA show a similar level of template activity. However, transcription of closed circular DNA is stimulated when negative supercoils are introduced by the addition of DNA topoisomerase II and supercoiling factor purified from the posterior silk gland of Bombyx mori. Dissection of transcription into pre- and postinitiation steps by the use of Sarkosyl reveals that DNA supercoiling promotes formation of a preinitiation complex. Furthermore, order of addition experiements suggest that DNA supercoiling facilitates a functional binding of transcription factor IID to the promoter.

Mizutani, Mitsuko; Ohta, Tsutomu; Hirose, Susumu (National Inst. of Genetics, Mishima (Japan)); Watanabe, Hajime; Handa, Hiroshi (Univ. of Tokyo (Japan))

1991-02-01

310

SILK PEPTIDE IMPROVING NEUROPROTECTIVE AND NEUROFUNCTIONAL EFFECTS AND A METHOD OF ITS PREPARATION  

UK PubMed Central (United Kingdom)

The present invention relates to silk peptide having neuroprotective and neurofunctional activitiesand its preparation method, and more particularly relates to a method of preparingsilk protein preferably having neuroprotective activity with weight averagemolecular weight of 200-100,000 by hydrolysis of silk fibroin; a compositionfor preventing or treating brain disease comprising silk peptide and pharmaceuticallyacceptable carrier; and a composition for improving brain function.

KIM Sung Su; KANG Yong Koo 107-404 Hansin Cheonggu Apt.; PARK Cheol Hyoung; LEE Sang-Hyung; JOO Wan-Seok; LEE Won Bok 219-902 Olympic Family Apt.; CHAE Hee Sun 205-904 Sinbanpo Hansin Apt.; NA Hye-Kyung 301-409 Hyundai 3cha Apt.

311

Nongenomic and genomic actions of an insect steroid coordinately regulate programmed cell death of anterior silk glands of Bombyx mori  

Directory of Open Access Journals (Sweden)

Full Text Available The insect steroid hormone 20-hydroxyecdysone (20E) induces programmed cell death of larva-specific tissues at pupal metamorphosis. In the silkworm Bombyx mori, the anterior silk gland undergoes cell death in response to the metamorphic peak titer of ecdysteroids in vivo and also to 20E in vitro. Although 20E elicits early gene activation, an additional 20E stimulus is required for completion of cell death. This additional stimulus involves caspase-3-like protease activation, indicating that 20E also acts through a nongenomic mechanism. Studies using various inhibitors, agonists, and antagonists have shown that cell condensation is under the control of 20E genomic action, and that 20E nongenomic action begins with 20E binding to the putative membrane-bound ecdysone receptor, which is probably a G-protein-coupled receptor. This step is followed by a signaling pathway comprising phospholipase C/inositol 3,4,5-triphosphate/Ca2+/protein kinase C/caspase-3-like protease, which induces DNA and nuclear fragmentation. Nuclear condensation is regulated by signaling of calmodulin/calmodulin-dependent protein kinase II (CaMKII), but CaMKII activation is independent of intracellular Ca2+ elevation. In addition, the genomic action of 20E is indispensable for driving its nongenomic action, indicating that crosstalk between genomic and nongenomic action plays a significant role in 20E-induced cell death.

M Manaboon; M Iga; S Sakurai

2008-01-01

312

Spectral analysis of induced color change on periodically nanopatterned silk films.  

Science.gov (United States)

We demonstrate controllable structural color based on periodic nanopatterned 2D lattices in pure protein films of silk fibroin. We show here periodic lattices in silk fibroin films with feature sizes of hundreds of nanometers that exhibit different colors as a function of varying lattice spacing. Further, when varying the index of refraction contrast between the nanopatterned lattice and its surrounding environment by applying liquids on top of the lattices, colorimetric shifts are observed. The effect is characterized experimentally and theoretically and a simple example of glucose concentration sensing is presented. This is the first example of a functional sensor based on silk fibroin optics. PMID:19997366

Amsden, Jason J; Perry, Hannah; Boriskina, Svetlana V; Gopinath, Ashwin; Kaplan, David L; Dal Negro, Luca; Omenetto, Fiorenzo G

2009-11-01

313

Spectral analysis of induced color change on periodically nanopatterned silk films.  

UK PubMed Central (United Kingdom)

We demonstrate controllable structural color based on periodic nanopatterned 2D lattices in pure protein films of silk fibroin. We show here periodic lattices in silk fibroin films with feature sizes of hundreds of nanometers that exhibit different colors as a function of varying lattice spacing. Further, when varying the index of refraction contrast between the nanopatterned lattice and its surrounding environment by applying liquids on top of the lattices, colorimetric shifts are observed. The effect is characterized experimentally and theoretically and a simple example of glucose concentration sensing is presented. This is the first example of a functional sensor based on silk fibroin optics.

Amsden JJ; Perry H; Boriskina SV; Gopinath A; Kaplan DL; Dal Negro L; Omenetto FG

2009-11-01

314

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

UK PubMed Central (United Kingdom)

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

Mobini S; Hoyer B; Solati-Hashjin M; Lode A; Nosoudi N; Samadikuchaksaraei A; Gelinsky M

2013-08-01

315

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

Science.gov (United States)

We introduce a novel Bombyx mori silk-based composite material developed for bone tissue engineering. Three-dimensional scaffolds were fabricated by embedding of natural degummed silk fibers in a matrix of regenerated fibroin, followed by freeze-drying. Different ratios of fibers to fibroin were investigated with respect to their influence on mechanical and biological properties. For all scaffold types, an interconnected porous structure suitable for cell penetration was proven by scanning electron microscopy. Compressive tests, carried out in static and cyclic mode under dry as well as wet conditions, revealed a strong impact of fiber reinforcement on compressive modulus and compressive stress. Cell culture experiments with human mesenchymal stem cells demonstrated that the fiber/fibroin composite scaffolds support cell attachment, proliferation, as well as differentiation along the osteoblastic lineage. Considering the excellent mechanical and biological properties, novel fiber/fibroin scaffolds appear to be an interesting structure for prospect studies in bone tissue engineering. PMID:23436754

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

2013-02-21

316

Characterization of fibroin and PEG-blended fibroin matrices for in vitro adhesion and proliferation of osteoblasts.  

Science.gov (United States)

Silk fibroin protein, isolated from cocoons of the domesticated mulberry silkworm, Bombyx mori, finds extensive application in biomaterial design. In this study, poly(ethylene glycol) (PEG) 4000 has been used for blending fibroin from both B. mori and Antheraea mylitta, the wild tropical non-mulberry silkworm. PEG-blended films have shown marked changes from the pure fibroin films with respect to thermal properties and mechanical properties. FT-IR spectroscopy confirmed incorporation of new functional groups like quinone oximes. Pure fibroin and PEG-blended fibroin films showed biocompatibility with the HOS osteosarcoma cell line. Von Kossa staining confirmed nodule formation due to mineralization and differentiation of osteoblasts on pure and blended matrices. On account of increased surface roughness, higher elongation percentage, higher thermostability and better activity of osteoblasts in terms of intracellular alkaline phosphatase production, PEG-blended A. mylitta fibroin film shows better potential than PEG-blended B. mori fibroin film for use as potential biomaterial. PMID:19323875

Acharya, Chitrangada; Kumary, T V; Ghosh, Sudip K; Kundu, S C

2009-01-01

317

Characteristics of Silk Fiber with and without Sericin Component: A Comparison between Bombyx mori and Philosamia ricini Silks  

Directory of Open Access Journals (Sweden)

Full Text Available The study aimed to investigate and compare some characteristics of Bombyx mori and Eri (Philosamia ricini) silks in different forms; with and without sericin. The protein contents were measured and find out the composition of the silk fibroin and sericin proteins by Lowry method. The secondary structure and thermal behavior of all kind of silk were determined by FT-IR and TA instrument, respectively. The B. mori composed of more amount of sericin content than that of Eri silk. FT-IR spectra indicated that the Eri silk was similar profile of silk with and without sericin, whereas B. mori silk showed dramatically differed. With sericin, B. mori composed of higher ratio random coil and ?-helix structures than ?-structure. With thermogravimetric analysis, both B. mori and Eri silk fibers without sericin showed higher stability than that silk fiber with sericin. This is due to the crystalline region of hydrophobic amino acid composed in the fibroin core protein. The differential scanning calorimetry thermogram of B. mori was differed from Eri silk fiber. It is a promising that characteristics of the silk were influenced by both silk components and silk varieties.

S. Prasong; S. Yaowalak; S. Wilaiwan

2009-01-01

318

In vivo regeneration of elastic lamina on fibroin biodegradable vascular scaffold.  

UK PubMed Central (United Kingdom)

PURPOSE: There is an increasing need for vascular grafts in the field of surgical revascularization. Artificial grafts offer alternative strategies to autologous tissue, however, small caliber (diameter <6 mm) ?vascular prosthesis are associated with a high incidence of thrombosis and early failure. Despite promising results, vascular tissue engineering is not yet a clinical reality due to the complexity of this approach. We aimed at investigating the use of fibroin, a biodegradable protein derived from silk, as an acellular vascular graft for in vivo recellularization. ? METHODS: We produced small caliber fibroin matrices by electrospinning to replace small arterial segments. Electrospun fibroin scaffolds were implanted into the abdominal aorta of Lewis rats by end-?to-end anastomosis. Seven days after implantation, fibroin matrices were recovered and processed for histological and immunohistochemical analysis.? RESULTS: Fibroin matrices allowed host cell infiltration, extracellular matrix remodeling, and ensured good patency of the grafts in the short term. Endothelial cells and smooth muscle cells were present in the explanted construct. Development of an elastic lamina adjacent to the lumen of the scaffold was observed with organization of intima and media layers. Vasa-vasorum were also present in the outer layer of the fibroin material.? CONCLUSIONS: Our results indicate that formation of vascular tissue containing elastin occurs already ?at 7 days after implantation on fibroin scaffold without in vitro cellularization. The use of an acellular electrospun silk fibroin tubular scaffold could be a promising strategy for in vivo regeneration of vascular tissue in the clinical reality.

Cattaneo I; Figliuzzi M; Azzollini N; Catto V; Farè S; Tanzi MC; Alessandrino A; Freddi G; Remuzzi A

2013-03-01

319

Characterization of Partial Coding Region Fibroin Gene on Wild Silkmoth Cricula trifenestrata Helfer (Lepidoptera: Saturniidae)  

Directory of Open Access Journals (Sweden)

Full Text Available The study was conducted to characterize coding region of wild silkmoth C. trifenestrata partial fibroin gene, and detect these gene potential as molecular marker. A total of six larvae C. trifenestrata were collected from Bogor, Purwakarta and Bantul Regency. Genomic DNA was extracted from silk gland individual larvae, then amplified by PCR method and sequenced. DNA sequenced result was 986 nucleotide partial fibroin gene of C. trifenestrata, which are comprising complete coding region of first exon (42 nucleotide), an intron (113 nucleotide), and partial of second was exon (831 nucleotide). Only coding region was characterized. Results showed that first exon very conserved in C. trifenestrata. These gene consisted of 31%, thymine, 28% guanine, 21% cytosine, and 19% adenine. Cytosine and thymine (sites of 25th and 35th respectively) were marker for C. trifenestrata species. The first exon encoding 14 amino acids. Valine amino acid (12th site) was marker to the species C. trifenestrata. The partial second exon consisted of guanine (32.7%), alanine (26.5%), thymine (21%) and cytosine (19.7%). These region encoded 277 amino acids, which were dominated by the alanine (27.8%) and glycine (21.66%). Alanine formed polyalanine sequence with different motifs namely: AAAAAAASS, AAAAAAAAAAAGSSG, AAAAAAAAAAAAGSGTGFGGYDS, AAAAAAAAAAGSSGRGGYDGVDGGYGSGSS, and AAAAAAAAAAAAGSSGRGLGGYDGWVDDGYGSGSGS.

Suriana; D. D. Solihin; R. R. Noor; A. M. Thohari

2011-01-01

320

Structural Origins of Silk Piezoelectricity.  

UK PubMed Central (United Kingdom)

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

Yucel T; Cebe P; Kaplan DL

2011-02-01

 
 
 
 
321

Structural Origins of Silk Piezoelectricity.  

Science.gov (United States)

Uniaxially oriented, piezoelectric silk films were prepared by a two-step method that involved: (1) air drying aqueous, regenerated silk fibroin solutions into films, and (2) drawing the silk films to a desired draw ratio. The utility of two different drawing techniques, zone drawing and water immersion drawing were investigated for processing the silk for piezoelectric studies. Silk films zone drawn to a ratio of ?= 2.7 displayed relatively high dynamic shear piezoelectric coefficients of d(14) = -1.5 pC/N, corresponding to over two orders of magnitude increase in d(14) due to film drawing. A strong correlation was observed between the increase in the silk II, ?-sheet content with increasing draw ratio measured by FTIR spectroscopy (C(?)? e(2.5) (?)), the concomitant increasing degree of orientation of ?-sheet crystals detected via WAXD (FWHM = 0.22° for ?= 2.7), and the improvement in silk piezoelectricity (d(14)? e(2.4) (?)). Water immersion drawing led to a predominantly silk I structure with a low degree of orientation (FWHM = 75°) and a much weaker piezoelectric response compared to zone drawing. Similarly, increasing the ?-sheet crystallinity without inducing crystal alignment, e.g. by methanol treatment, did not result in a significant enhancement of silk piezoelectricity. Overall, a combination of a high degree of silk II, ?-sheet crystallinity and crystalline orientation are prerequisites for a strong piezoelectric effect in silk. Further understanding of the structural origins of silk piezoelectricity will provide important options for future biotechnological and biomedical applications of this protein. PMID:23335872

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

2011-01-13

322

Precise Patterning of Silk Microstructures Using Photolithography.  

UK PubMed Central (United Kingdom)

Photolithography is used in conjunction with a "silk fibroin photoresist" to form precise protein microstructures directly and rapidly on a variety of substrates. High resolution features in two and three dimensions with line widths down to 1 micrometer are formed. Photo-crosslinked protein structures guide cell adhesion, providing precise spatial control of cells without requiring adhesive ligands.

Kurland NE; Dey T; Kundu SC; Yadavalli VK

2013-08-01

323

Production of fine powder from silk by radiation  

Energy Technology Data Exchange (ETDEWEB)

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)

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

324

SILK THREAD CONTAINING SPIDER THREAD PROTEIN AND SILKWORM PRODUCING THE SILK THREAD  

UK PubMed Central (United Kingdom)

By using a transgenic silkworm having a gene, which encodes a spider thread protein having desired properties (a high strength, a high elongation, etc.), transferred thereinto without injuring silkworm fibroin H-chain gene by a means of, for example, using the transposon function, the spider thread protein having the desired properties is produced by the transgenic silkworm without lowering the strength or elongation of silk thread produced by the transgenic silkworm, thereby providing a hybrid silk of spider thread with silk thread having the desired properties.

HIRAMATSU Shingo; MORIYAMA Hiromitsu; ASAOKA Ryota; MORITA Ken; TANAKA Takashi; YAMADA Katsushige; OBRIEN John Philip; FAHNESTOCK Stephen R.

325

Spinning an elastic ribbon of spider silk.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Sicarid spider Loxosceles laeta spins broad but very thin ribbons of elastic silk that it uses to form a retreat and to capture prey. A structural investigation into this spider's silk and spinning apparatus shows that these ribbons are spun from a gland homologous to the major ampullate gland o...

Knight, David P; Vollrath, Fritz

326

Solubilization of silk protein by radiation  

Energy Technology Data Exchange (ETDEWEB)

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)

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

2002-03-01

327

Functional design of spider's silk  

Science.gov (United States)

The orb-web weaving spiders produce a broad range of high performance structural fibers (i.e. silks) with mechanical properties that are superbly matched to their function. Our interest in these materials stems both from an interest in the biology of the spiders and the design of their webs and also from a desire to discover principles of mechanical design of protein-based structural materials that can guide the development of novel bio-engineered materials. All spiders produce silks, but the orb-web weaving spiders are unique in their ability to produce seven different silks, each from distinct gland/spinneret complexes. Considering the wide diversity of spider species, there is likely to be an enormous range of material properties available in spider silk. However, at present, we only have information on two species of spiders, and only two of their seven silks have been studied in any detail. These are: (1) the silk produced by the major ampullate gland, which forms the safety-line or dragline of the spider and also is used to form the frame of its orb-web, and (2) the viscid silk produced by the flagelliform gland, which forms the glue-covered catching spiral of the web. In this paper we describe several aspects of the mechanical design of the dragline and viscid silks produced by the spider Araneus diadematus.

Gosline, John; Guerette, Paul; Ortlepp, Christine

1996-02-01

328

Silk-mediated synthesis and modification of photoluminescent ZnO nanoparticles  

International Nuclear Information System (INIS)

[en] 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.

2012-01-01

329

Silk-mediated synthesis and modification of photoluminescent ZnO nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

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.

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

330

Conservation of essential design features in coiled coil silks.  

Science.gov (United States)

Silks are strong protein fibers produced by a broad array of spiders and insects. The vast majority of known silks are large, repetitive proteins assembled into extended beta-sheet structures. Honeybees, however, have found a radically different evolutionary solution to the need for a building material. The 4 fibrous proteins of honeybee silk are small ( approximately 30 kDa each) and nonrepetitive and adopt a coiled coil structure. We examined silks from the 3 superfamilies of the Aculeata (Hymenoptera: Apocrita) by infrared spectroscopy and found coiled coil structure in bees (Apoidea) and in ants (Vespoidea) but not in parasitic wasps of the Chrysidoidea. We subsequently identified and sequenced the silk genes of bumblebees, bulldog ants, and weaver ants and compared these with honeybee silk genes. Each species produced orthologues of the 4 small fibroin proteins identified in honeybee silk. Each fibroin contained a continuous predicted coiled coil region of around 210 residues, flanked by 23-160 residue length N- and C-termini. The cores of the coiled coils were unusually rich in alanine. There was extensive sequence divergence among the bee and ant silk genes (<50% similarity between the alignable regions of bee and ant sequences), consistent with constant and equivalent divergence since the bee/ant split (estimated to be 155 Myr). Despite a high background level of sequence diversity, we have identified conserved design elements that we propose are essential to the assembly and function of coiled coil silks. PMID:17703050

Sutherland, Tara D; Weisman, Sarah; Trueman, Holly E; Sriskantha, Alagacone; Trueman, John W H; Haritos, Victoria S

2007-08-16

331

Conservation of essential design features in coiled coil silks.  

UK PubMed Central (United Kingdom)

Silks are strong protein fibers produced by a broad array of spiders and insects. The vast majority of known silks are large, repetitive proteins assembled into extended beta-sheet structures. Honeybees, however, have found a radically different evolutionary solution to the need for a building material. The 4 fibrous proteins of honeybee silk are small ( approximately 30 kDa each) and nonrepetitive and adopt a coiled coil structure. We examined silks from the 3 superfamilies of the Aculeata (Hymenoptera: Apocrita) by infrared spectroscopy and found coiled coil structure in bees (Apoidea) and in ants (Vespoidea) but not in parasitic wasps of the Chrysidoidea. We subsequently identified and sequenced the silk genes of bumblebees, bulldog ants, and weaver ants and compared these with honeybee silk genes. Each species produced orthologues of the 4 small fibroin proteins identified in honeybee silk. Each fibroin contained a continuous predicted coiled coil region of around 210 residues, flanked by 23-160 residue length N- and C-termini. The cores of the coiled coils were unusually rich in alanine. There was extensive sequence divergence among the bee and ant silk genes (<50% similarity between the alignable regions of bee and ant sequences), consistent with constant and equivalent divergence since the bee/ant split (estimated to be 155 Myr). Despite a high background level of sequence diversity, we have identified conserved design elements that we propose are essential to the assembly and function of coiled coil silks.

Sutherland TD; Weisman S; Trueman HE; Sriskantha A; Trueman JW; Haritos VS

2007-11-01

332

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

Energy Technology Data Exchange (ETDEWEB)

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.

Hou Aiqin, E-mail: aiqinhou@dhu.edu.c [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, 3H, 2999 North Renmin Road, Songjiang, Shanghai 201620 (China); Chen Huawei [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, 3H, 2999 North Renmin Road, Songjiang, Shanghai 201620 (China)

2010-03-15

333

Comparative Proteomics Reveal Diverse Functions and Dynamic Changes of Bombyx mori Silk Proteins Spun from Different Development Stages.  

UK PubMed Central (United Kingdom)

Silkworms (Bombyx mori) produce massive amounts of silk proteins to make cocoons during the final stages of larval development. Although the major components, fibroin and sericin, have been the focus for a long time, few researchers have realized the complexity of the silk proteome. We collected seven kinds of silk fibers spun by silkworm larvae at different developmental stages: the silks spun by new hatched larvae, second instar day 0 larvae, third instar day 0 larvae, fourth instar day 0 larvae, and fourth instar molting larvae, the scaffold silk used to attach the cocoon to the substrate and the cocoon silk. Analysis by liquid chromatography-tandem mass spectrometry identified 500 proteins from the seven silks. In addition to the expected fibroins, sericins, and some known protease inhibitors, we also identified further protease inhibitors, enzymes, proteins of unknown function, and other proteins. Unsurprisingly, our quantitative results showed fibroins and sericins were the most abundant proteins in all seven silks. Except for fibroins and sericins, protease inhibitors, enzymes, and proteins of unknown function were more abundant than other proteins. We found significant change in silk protein compositions through development, being consistent with their different biological functions and complicated formation.

Dong Z; Zhao P; Wang C; Zhang Y; Chen J; Wang X; Lin Y; Xia Q

2013-10-01

334

Determining dihedral angles and local structure in silk peptide by 13C-2H REDOR.  

UK PubMed Central (United Kingdom)

13C-2H REDOR NMR experiments were performed on 30-residue (AlaGly)15 silk I mimics of Bombyx mori silk fibroin to gain structural details about the elusive structure of the silk I conformation. 13C,2H-labeling strategies are illustrated for measuring individual dihedral angles in peptides and for determining local structure by REDOR. A major turn of type II character is found in the region Gly(14)-Ala(17).

Gullion T; Kishore R; Asakura T

2003-06-01

335

Development of silk-based scaffolds for tissue engineering of bone from human adipose derived stem cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Silk fibroin is a potent alternative to other biodegradable biopolymers for bone tissue engineering (TE), because of its tunable architecture and mechanical properties, and its demonstrated ability to support bone formation both in vitro and in vivo. In this study, we investigated a range of silk sc...

Correia, Cristina; Bhumiratana, Sarindr; Yan, Leping; Oliveira, A. L.; Gimble, Jeffrey M.; Rockwood, Danielle; Kaplan, David

336

Self-assembly in the major ampullate gland of Nephila clavipes  

CERN Multimedia

We present a tentative interpretation of the origin of nematic liquid crystalline order exhibited by dragline silk fibroin solutions collected from the spider Nephila clavipes. Liquid crystallinity is thought to confer certain rheological properties on the fibroin solution which are exploited during the dragline spinning process. We show that the feasibility of liquid crystallinity under physiological conditions depends critically on parameters characterising the amino-acid sequence of the fibroin molecules.

Braun, F N

2002-01-01

337

Effect of degumming condition on the solution properties and electrospinnablity of regenerated silk solution.  

UK PubMed Central (United Kingdom)

The application of silk on tissue engineering scaffolds has been studied intensively because silk has an electrospinning technique using a good blood compatibility, excellent cytocompatibility and biodegradability. Silk consists of two polymers, fibroin and sericin. In spite of importance of sericin, most studies were focused on the fibroin only and the effect of residual sericin on the electrospinning performance of silk has not been considered. In this study, regenerated silk with different residual sericin contents was prepared by controlling the degumming conditions. The effects of the degumming conditions on the solution properties and electrospinning performance of silk were examined. The fast protein liquid chromatography (FPLC) measurements confirmed that the molecular weight of the regenerated silk decreased slightly with increasing residual sericin content. More molecular aggregation of silk occurred with increasing sericin content, resulting in an increase in the solution turbidity of formic acid. All silk formic acid solutions exhibited almost Newtonian fluid behavior and the viscosity increased with increasing sericin content. Interestingly, the dope solution viscosity of silk increased remarkably at sericin contents <1% (or degumming ratio >25%) leading to significant improvements in electrospinnability and an increase in the fiber diameter of the silk web.

Ko JS; Yoon K; Ki CS; Kim HJ; Bae do G; Lee KH; Park YH; Um IC

2013-04-01

338

Silk ionomers for encapsulation and differentiation of human MSCs.  

UK PubMed Central (United Kingdom)

The response of human bone marrow derived human mesenchymal stem cells (hMSCs) encapsulated in silk ionomer hydrogels was studied. Silk aqueous solutions with silk-poly-L-lysine or silk-poly-L-glutamate were formed into hydrogels via ultrasonication in situ with different net charges. hMSCs were encapsulated within the hydrogels and the impact of matrix charge was assessed over weeks in osteogenic, adipogenic and maintenance growth media. These modified silk charged polymers supported cell viability and proliferative potential, and the hMSCs were able to differentiate toward osteogenic or adipogenic lineages in the corresponding differentiation media. The silk/silk-poly-L-lysine hydrogels exhibited a positive effect on selective osteogenesis of hMSCs, inducing differentiation toward an osteogenic lineage even in the absence of osteogenic supplements, while also inhibiting adipogenesis. In contrast, silk/silk fibroin-poly-L-glutamate hydrogels supported both osteogenic and adipogenic differentiation of hMSCs when cultured under induction conditions. The results demonstrate the potential utility of silk-based ionomers in gel formats for hMSCs encapsulation and for directing hMSCs long term functional differentiation toward specific lineages.

Calabrese R; Kaplan DL

2012-10-01

339

Silk ionomers for encapsulation and differentiation of human MSCs.  

Science.gov (United States)

The response of human bone marrow derived human mesenchymal stem cells (hMSCs) encapsulated in silk ionomer hydrogels was studied. Silk aqueous solutions with silk-poly-L-lysine or silk-poly-L-glutamate were formed into hydrogels via ultrasonication in situ with different net charges. hMSCs were encapsulated within the hydrogels and the impact of matrix charge was assessed over weeks in osteogenic, adipogenic and maintenance growth media. These modified silk charged polymers supported cell viability and proliferative potential, and the hMSCs were able to differentiate toward osteogenic or adipogenic lineages in the corresponding differentiation media. The silk/silk-poly-L-lysine hydrogels exhibited a positive effect on selective osteogenesis of hMSCs, inducing differentiation toward an osteogenic lineage even in the absence of osteogenic supplements, while also inhibiting adipogenesis. In contrast, silk/silk fibroin-poly-L-glutamate hydrogels supported both osteogenic and adipogenic differentiation of hMSCs when cultured under induction conditions. The results demonstrate the potential utility of silk-based ionomers in gel formats for hMSCs encapsulation and for directing hMSCs long term functional differentiation toward specific lineages. PMID:22824008

Calabrese, Rossella; Kaplan, David L

2012-07-21

340

Structural Properties of Silk Electro-Gels  

Science.gov (United States)

The interest in Bombyx Mori silk emerges from its biocompatibility and its structural superiority to synthetic polymers. Our particular interest lies in understanding the capabilities of silk electro-gels because of their reversibility and tunable adhesion. We create an electro-gel by applying a DC electric potential across a reconstituted silk fibroin solution derived directly from Bombyx Mori cocoons. This process leads to the intermolecular self-assembly of fibroin proteins into a weak gel. In this talk we will present our results on the effects of applied shear on electro-gels. We quantify the structural properties while dynamically imaging shear induced fiber formation; known as fibrillogenesis. It is observed that the mechanical properties and microstructure of these materials are highly dependent on shear history. We will also discuss the role of surface modification, through micro-patterning, on the observed gel structure. Our results provide an understanding of both the viscoelastiticity and microstucture of reconstituted silks that are being utilized as tissue scaffolds.

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

2013-03-01

 
 
 
 
341

?????????????? Preparation of Antimicrobial Silk Hydrogels for Surgical Dressings  

Directory of Open Access Journals (Sweden)

Full Text Available ????????????????????????????????????????????????X???????????????zeta????????????????????????zeta????????????????????????????????????????????????????????????-????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Using quaternary ammonium salts (QAS) as initiating agents, silk fibroin aqueous solutions were induced to gel rapidly. The structure, zeta-potential change and thermal stability properties of QAS-induced silk gel were charac- terized by means of X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), zeta- potential measurements and differential thermal analysis (DTA). The results show that QAS-induced silk gelation is accompanied by the formation of ?-sheets and less negative zeta-potential values. With the observation of SEM, the internal morphology of gel exhibited a porous three-dimensional network structure. In vitro degradation and DTA analysis revealed that QAS-induced fibroin gel was not quite stable and disintegrated more easily in the enzyme solu- tion. Also, QAS is amorphous or metastable crystal state in silk gel and thus easy to release and diffuse. The antibacte- rial test in vitro suggested that silk-QAS gel showed distinctly antibacterial activities against both Gram-positive and Gram-negative bacteria. In situ antimicrobial silk hydrogel is expected to be used for a surgical dressing.

???; ???; ??; ??; ???

2012-01-01

342

Nanocomposite gold-silk nanofibers.  

UK PubMed Central (United Kingdom)

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 (SNF(seed)). Following gold reduction, there was a 2-fold increase in particle diameter confirmed by the appearance of a strong absorption peak at 525 nm. AuNPs were dispersed throughout the AuNP-doped silk nanofibers (SNFs(Au)). The Young's modulus of the SNFs(Au) was almost 70% higher than that of SNFs. SNFs(Au) were modified with the arginine-glycine-aspartic acid (RGD) peptide. Human mesenchymal stem cells that were cultured on RGD-modified SNF(Au) had a more than 2-fold larger cell area compared to the cells cultured on bare SNFs; SNF(Au) also increased cell size. This approach may be used to alter the cell-material interface in tissue engineering and other applications.

Cohen-Karni T; Jeong KJ; Tsui JH; Reznor G; Mustata M; Wanunu M; Graham A; Marks C; Bell DC; Langer R; Kohane DS

2012-10-01

343

TOWARDS A ROUTINE METHODOLOGY FOR ASSESSING THE CONDITION OF HISTORIC SILK  

Directory of Open Access Journals (Sweden)

Full Text Available To ensure continued access and long-term preser vation itis essential to understand the condition of an artefact, andthe behaviour of its component materials, in order to setlimits on display and handling. In support of curators andconservators of collections with historic textiles, we aredeveloping rapid and routine technology, involving nearinfrared spectroscopy coupled with multivariate analysis,which, when applied non-invasively on-site, will allow theestimation of the state of deterioration of silk fabrics.Pursuing this aim, we have now carried out further analyticalstudies on silks artificially aged under different regimesfor up to 20 days: dry thermal, high heat and humidity, andsunlight equivalent irradiation. The tensile strengths, yellownessindices, apparent molecular weights of fibroin, andnear infrared spectral sorbed moisture parameters for theaged silks were determined. The mechanical performanceof silk diminished exponentially over each ageing timecourse. For the various silks, the increases in yellownessindices and decreases in fibroin molecular weights andmoisture contents showed similar kinetics to the mechanicalchanges. While each parameter was correlated with thetensile strength, silks exposed to the different acceleratedageing factors exhibited diverse correlations. It is concludedthat, when formulating a general model for characterisingthe condition of silk using chemometrics, the referenceset should include examples of silks which have beenexposed to the full variety of ageing factors.

Jeongjin Kim; Paul Wyeth

2009-01-01

344

Microporous carbon nanoplates from regenerated silk proteins for supercapacitors.  

UK PubMed Central (United Kingdom)

Novel carbon-based microporous nanoplates containing numerous heteroatoms (H-CMNs) are fabricated from regenerated silk fibroin by the carbonization and activation of KOH. The H-CMNs exhibit superior electrochemical performance, displaying a specific capacitance of 264 F/g in aqueous electrolytes, a specific energy of 133 Wh/kg, a specific power of 217 kW/kg, and a stable cycle life over 10000 cycles.

Yun YS; Cho SY; Shim J; Kim BH; Chang SJ; Baek SJ; Huh YS; Tak Y; Park YW; Park S; Jin HJ

2013-04-01

345

Implication of silk film RGD availability and surface roughness on cytoskeletal organization and proliferation of primary rat bone marrow cells.  

Science.gov (United States)

To design and fabricate next-generation tissue engineering materials, the understanding of cell responses to material surfaces is required. Surface topography presents powerful cues for cells and can strongly influence cell morphology, adhesion, and proliferation, but the mechanisms mediating this cell response remain unclear. In this report, we have investigated the effects of nanoroughness assemblies of silk fibroin protein membranes and RGD sequences fabricated from two different silk fibroin sources, that is, mulberry (Bombyx mori) and nonmulberry (Antheraea mylitta), on cytoskeletal organization, proliferation, and viability using primary rat bone marrow cells. To vary surface roughness, silk fibroin substrates were treated with graded ethanol (50%-100% v/v) to produce nanoarchitectures in the range of 1-12 nm height. The graded alcohol treatments have been found to produce nanoscale topographies of reproducible height in a much faster and cheaper way. The results showed no difference in cell proliferation within the same treatment groups for both silk types. However, a change in cell response in terms of good cytoskeleton organization, actin development, cell spreading, and strong binding to substratum using A. mylitta fibroin protein films having RGD sequences was observed. This finding provides the information that the nanoroughness affects cellular processes in a cell-specific manner and may be helpful for the development of smart silk-based biomaterials especially for directing cell differentiation and regenerative therapies. PMID:20214452

Mandal, Biman B; Das, Soumen; Choudhury, Koel; Kundu, Subhas C

2010-07-01

346

Implication of silk film RGD availability and surface roughness on cytoskeletal organization and proliferation of primary rat bone marrow cells.  

UK PubMed Central (United Kingdom)

To design and fabricate next-generation tissue engineering materials, the understanding of cell responses to material surfaces is required. Surface topography presents powerful cues for cells and can strongly influence cell morphology, adhesion, and proliferation, but the mechanisms mediating this cell response remain unclear. In this report, we have investigated the effects of nanoroughness assemblies of silk fibroin protein membranes and RGD sequences fabricated from two different silk fibroin sources, that is, mulberry (Bombyx mori) and nonmulberry (Antheraea mylitta), on cytoskeletal organization, proliferation, and viability using primary rat bone marrow cells. To vary surface roughness, silk fibroin substrates were treated with graded ethanol (50%-100% v/v) to produce nanoarchitectures in the range of 1-12 nm height. The graded alcohol treatments have been found to produce nanoscale topographies of reproducible height in a much faster and cheaper way. The results showed no difference in cell proliferation within the same treatment groups for both silk types. However, a change in cell response in terms of good cytoskeleton organization, actin development, cell spreading, and strong binding to substratum using A. mylitta fibroin protein films having RGD sequences was observed. This finding provides the information that the nanoroughness affects cellular processes in a cell-specific manner and may be helpful for the development of smart silk-based biomaterials especially for directing cell differentiation and regenerative therapies.

Mandal BB; Das S; Choudhury K; Kundu SC

2010-07-01

347

Silk microgels formed by proteolytic enzyme activity.  

UK PubMed Central (United Kingdom)

The proteolytic enzyme ?-chymotrypsin selectively cleaves the amorphous regions of silk fibroin protein (SFP) and allows the crystalline regions to self-assemble into silk microgels (SMGs) at physiological temperature. These microgels consist of lamellar crystals in the micrometer scale, in contrast to the nanometer-scaled crystals in native silkworm fibers. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and zeta potential results demonstrated that ?-chymotrypsin utilized only the non-amorphous domains or segments of the heavy chain of SFP to form negatively charged SMGs. The SMGs were characterized in terms of size, charge, structure, morphology, crystallinity, swelling kinetics, water content and thermal properties. The results suggest that the present technique of preparing SMGs by ?-chymotrypsin is simple and efficient, and that the prepared SMGs have useful features for studies related to biomaterial and pharmaceutical needs. This process is also an easy way to obtain the amorphous peptide chains for further study.

Samal SK; Dash M; Chiellini F; Kaplan DL; Chiellini E

2013-09-01

348

Statistical approaches for investigating silk properties  

Science.gov (United States)

Amino acid repeats or motifs have engendered interest because of their significance for protein physical characteristics as well as folding properties. Spider dragline silk proteins are unique because they are composed of long repetitive sections and relatively short non-repetitive sections that are known to interact to generate the very peculiar mechanical and solubility properties of silk. Computational analysis compared with in vitro measurements suggest that the silks achieve their unique pattern of extreme solubility inside the spider glands/complete insolubility outside by correlating their repetitive hydrophobic regions through a type of stochastic resonance, generated by the addition of the non-repetitive sequences to a basically periodic hydrophobicity pattern.

Zbilut, J. P.; Scheibel, T.; Huemmerich, D.; Webber, C. L., Jr.; Colafranceschi, M.; Giuliani, A.

2006-02-01

349

The role of 3D structure and protein conformation on the innate and adaptive immune responses to silk-based biomaterials.  

Science.gov (United States)

We have investigated monocyte and T cell responsiveness to silk based biomaterials of different physico-chemical characteristics. Here we report that untransformed CD14+ human monocytes respond to overnight exposure to silk fibroin-based biomaterials in tridimensional form by IL-1? and IL-6, but not IL-10 gene expression and protein production. In contrast, fibroin based materials in bidimensional form are unable to stimulate monocyte responsiveness. The elicitation of these effects critically requires contact between biomaterials and responding cells, is not sustained and becomes undetectable in longer term cultures. We also observed that NF-?? and p38 MAP kinase play key roles in monocyte activation by silk-based biomaterials. On the other hand, fibroin based materials, irrespective of their physico-chemical characteristics appeared to be unable to induce the activation of peripheral blood T cells from healthy donors, as evaluated by the expression of activation markers and IFN-? gene. PMID:23896003

Bhattacharjee, Maumita; Schultz-Thater, Elke; Trella, Emanuele; Miot, Sylvie; Das, Sanskrita; Loparic, Marko; Ray, Alok R; Martin, Ivan; Spagnoli, Giulio C; Ghosh, Sourabh

2013-07-26

350

The role of 3D structure and protein conformation on the innate and adaptive immune responses to silk-based biomaterials.  

UK PubMed Central (United Kingdom)

We have investigated monocyte and T cell responsiveness to silk based biomaterials of different physico-chemical characteristics. Here we report that untransformed CD14+ human monocytes respond to overnight exposure to silk fibroin-based biomaterials in tridimensional form by IL-1? and IL-6, but not IL-10 gene expression and protein production. In contrast, fibroin based materials in bidimensional form are unable to stimulate monocyte responsiveness. The elicitation of these effects critically requires contact between biomaterials and responding cells, is not sustained and becomes undetectable in longer term cultures. We also observed that NF-?? and p38 MAP kinase play key roles in monocyte activation by silk-based biomaterials. On the other hand, fibroin based materials, irrespective of their physico-chemical characteristics appeared to be unable to induce the activation of peripheral blood T cells from healthy donors, as evaluated by the expression of activation markers and IFN-? gene.

Bhattacharjee M; Schultz-Thater E; Trella E; Miot S; Das S; Loparic M; Ray AR; Martin I; Spagnoli GC; Ghosh S

2013-11-01

351

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

UK PubMed Central (United Kingdom)

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 ?-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.

An B; Jenkins JE; Sampath S; Holland GP; Hinman M; Yarger JL; Lewis R

2012-12-01

352

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

Science.gov (United States)

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 ?-sheet nanostructures, while MaSp2 proteins form random coil and helical structures. To test if this behavior of natural silk proteins could be reproduced by recombinantly produced spider silk mimic protein, recombinant MaSp1/MaSp2 mixed fibers as well as chimeric silk fibers from MaSp1 and MaSp2 sequences in a single protein were produced based on the variable ratio and conserved motifs of MaSp1 and MaSp2 in native silk fiber. Mechanical properties, solid-state NMR, and XRD results of tested synthetic fibers indicate the differing roles of MaSp1 and MaSp2 in the fiber and verify the importance of postspin stretching treatment in helping the fiber to form the proper spatial structure. PMID:23110450

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

2012-11-08

353

Silk production in a spider involves acid bath treatment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We studied physiological conditions during the spinning of dragline silk by the garden cross spider, Araneus diadematus. Silk is converted from the liquid feedstock in the gland into a solid thread via a tapering tubular duct and exits at a spigot. The distal part of the tubule appears specialized f...

Vollrath, F.; Knight, D. P.; Hu, X. W.

354

Preferential codon usage and two types of repetitive motifs in the fibroin gene of the Chinese oak silkworm, Antheraea pernyi.  

UK PubMed Central (United Kingdom)

In this paper we describe the peculiar structures and preferential codon usage found in wild silkworm fibroin genes. We determined a 1350 bp nucleotide sequence from the Chinese oak silkworm, Antheraea pernyi. The deduced amino acid sequence was partitioned into thirteen polyalanine-containing repetitive motifs, which was one of the characteristics of Antheraea fibroins. Eleven of these arrays can be classified into two types of motifs depending on difference in amino acid sequences following polyalanine. Repetitive motifs structurally similar to those of A. pernyi were detected in a homologue of the Japanese oak silkworm, Antheraea yamamai. The most remarkable feature of this study was preferential codon usage, especially seen in alanine synonymous codons within both homologues of Antheraea: isocodon GCA most frequently occurred in alanine isocodons. In contrast, GCU isocodon was the most abundant in Bombyx mori fibroin heavy chain that lacks polyalanine arrays. This result strongly suggests different modes of selective constraint between the two types of fibroin gene. The similar finding that GCA isocodon was most frequent in two dragline silk sequences of the spider, Nephila clavipes, is consistent with our results because of the repetitive polyalanine-containing arrays seen in spider dragline silk.

Yukuhiro K; Kanda T; Tamura T

1997-02-01

355

Promoter sequence of fibroin gene assigned by in vitro transcription system.  

UK PubMed Central (United Kingdom)

We have shown that the silk fibroin gene from Bombyx mori is faithfully transcribed in an in vitro transcription system of the HeLa cell extract prepared by the method of Manley et al. [Manley, J. L., Fire, A., Cano, A., Sharp, P. A. & Gefter, M. L. (1980) Proc. Natl. Acad. Sci. USA 77, 3855-3859]. Using this system and a series of deletion mutants of fibroin gene, we have assigned the promoter sequence of fibroin gene. The 5' boundary of the promoter is around nucleotide position -29, indicating that most of the T-A-T-A-A-A-A sequence (-30 to -24) is essential for the promoter function, where the transcription initiation point of fibroin gene is assigned as nucleotide position +1 [Tsuda, M., Ohshima, Y. & Suzuki, Y. (1979) Proc. Natl. Acad. Sci. USA 76, 4872-4876]. The 3' boundary is around nucleotide position +6. However, to support the efficient, faithful transcription, some additional (more than 26 but less than 41) nucleotides of nonspecific origin are required at the 5' side of -29. Functions ascribed to the promoter region are discussed.

Tsujimoto Y; Hirose S; Tsuda M; Suzuki Y

1981-08-01

356

Characterization and assembly of a GFP-tagged cylindriform silk into hexameric complexes.  

UK PubMed Central (United Kingdom)

Spider silk has been studied extensively for its attractive mechanical properties and potential applications in medicine and industry. The production of spider silk, however, has been lagging behind for lack of suitable systems. Our approach focuses on solving the production of spider silk by designing, expressing, purifying and characterizing the silk from cylindriform glands. We show that the cylindriform silk protein, in contrast to the commonly used dragline silk protein, is fully folded and stable in solution. With the help of GFP as a fusion tag we enhanced the expression of the silk protein in Escherichia coli and could optimize the downstream processing. Secondary structures analysis by circular dichroism and FTIR shows that the GFP-Silk fusion protein is predominantly ?-helical, and that pH can trigger a ?- to ?-transition resulting in aggregation. Structural analysis by small angle x-ray scattering suggests that the GFP-Silk exists in the form of a hexamer in solution.

Oster C; Bonde JS; Bulow L; Dicko C

2013-08-01

357

Study on cast membranes and electrospun nanofibers made from keratin/fibroin blends.  

UK PubMed Central (United Kingdom)

Keratin regenerated from wool and fibroin regenerated from silk were mixed in different proportions using formic acid as the common solvent. Both solutions were cast to obtain films and electrospun to produce nanofibers. Scanning electron microscopy investigation showed that, for all electrospun blends (except for 100% keratin where bead defects are present), the fiber diameter of the mats ranged from 900 (pure fibroin) to 160 nm (pure keratin). FTIR and DSC analysis showed that the secondary structure of the proteins was influenced by the blend ratios and the process used (casting or electrospinning). Prevalence of beta-sheet supramolecular structures was observed in the films, while proteins assembled in alpha-helix/random coil structures were observed in nanofibers. Higher solution viscosity, thinner filaments, and differences in the thermal and structural properties were observed for the 50/50 blend because of the enhanced interactions between the proteins.

Zoccola M; Aluigi A; Vineis C; Tonin C; Ferrero F; Piacentino MG

2008-10-01

358

Study on cast membranes and electrospun nanofibers made from keratin/fibroin blends.  

Science.gov (United States)

Keratin regenerated from wool and fibroin regenerated from silk were mixed in different proportions using formic acid as the common solvent. Both solutions were cast to obtain films and electrospun to produce nanofibers. Scanning electron microscopy investigation showed that, for all electrospun blends (except for 100% keratin where bead defects are present), the fiber diameter of the mats ranged from 900 (pure fibroin) to 160 nm (pure keratin). FTIR and DSC analysis showed that the secondary structure of the proteins was influenced by the blend ratios and the process used (casting or electrospinning). Prevalence of beta-sheet supramolecular structures was observed in the films, while proteins assembled in alpha-helix/random coil structures were observed in nanofibers. Higher solution viscosity, thinner filaments, and differences in the thermal and structural properties were observed for the 50/50 blend because of the enhanced interactions between the proteins. PMID:18798669

Zoccola, Marina; Aluigi, Annalisa; Vineis, Claudia; Tonin, Claudio; Ferrero, Franco; Piacentino, Marco G

2008-09-18

359

Construction of a functional silk-based biomaterial complex with immortalized chondrocytes in vivo.  

UK PubMed Central (United Kingdom)

Objective: To explore the feasibility of constructing a functional biomaterial complex with regenerated silk fibroin membrane and immortalized chondrocytes in vivo. Methods: RACs (rat auricular chondrocytes) were transfected with the lentivirus vector pGC-FU-hTERT-3FLAG or pGC-FU-GFP-3FLAG, encoding the human telomerase reverse transcriptase (hTERT) or GFP gene. The effects of regenerated silk fibroin film on the adhesion, growth of immortalized chondrocytes and expression of collagen II in vitro were analyzd with immunofluorescent histochemistry. Results: Immortalized RACs were transformed. Induction by nutrient medium promoted higher expression levels of collagen II in transformed chondrocytes. The regenerated silk fibroin film was not cytotoxic to immortalized chondrocytes and had no adverse influence on their adhesion. Collagen II expression was good in the immortalized chondrocytes in vivo. Conclusion: The construction of a silk-based biomaterial complex with immortalized chondrocytes may provide a feasible kind of functional biomaterial for the repair of cartilage defects in clinical applications.

Ni Y; Jiang Y; Wen J; Shao Z; Chen X; Sun S; Yu H; Li W

2013-04-01

360

Tuning chemical and physical cross-links in silk electrogels for morphological analysis and mechanical reinforcement.  

UK PubMed Central (United Kingdom)

Electrochemically controlled, reversible assembly of biopolymers into hydrogel structures is a promising technique for on-demand cell or drug encapsulation and release systems. An electrochemically sol-gel transition has been demonstrated in regenerated Bombyx mori silk fibroin, offering a controllable way to generate biocompatible and reversible adhesives and other biomedical materials. Despite the involvement of an electrochemically triggered electrophoretic migration of the silk molecules, the mechanism of the reversible electrogelation remains unclear. It is, however, known that the freshly prepared silk electrogels (e-gels) adopt a predominantly random coil conformation, indicating a lack of cross-linking as well as thermal, mechanical, and morphological stabilities. In the present work, the tuning of covalent and physical ?-sheet cross-links in silk hydrogels was studied for programming the structural properties. Scanning electron microscopy (SEM) revealed delicate morphology, including locally aligned fibrillar structures, in silk e-gels, preserved by combining glutaraldehyde-cross-linking and ethanol dehydration. Fourier transform infrared (FTIR) spectroscopic analysis of either electrogelled, vortex-induced or spontaneously formed silk hydrogels showed that the secondary structure of silk e-gels was tunable between non-?-sheet-dominated and ?-sheet-dominated states. Dynamic oscillatory rheology confirmed the mechanical reinforcement of silk e-gels provided by controlled chemical and physical cross-links. The selective incorporation of either chemical or physical or both cross-links into the electrochemically responsive, originally unstructured silk e-gel should help in the design for electrochemically responsive protein polymers.

Lin Y; Xia X; Shang K; Elia R; Huang W; Cebe P; Leisk G; Omenetto F; Kaplan DL

2013-08-01

 
 
 
 
361

Ultrastructure of the silk glands in three adult females of sphecid wasps of the genus Microstigmus (Hymenoptera: Pemphredoninae)/ Ultraestructura de las glándulas de seda en hembras adultas de tres especies de avispas del género Microstigmus (Hymenoptera: Sphecidae: Pemphredoninae)  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Se describe la ultraestructura de las glándulas de la seda en tres hembras adultas de avispas Sphecidae del género Microstigmus. Las glándulas individualmente se dispersan en la porción más posterior del metasoma, y cada una de ellas está formada por una unidad secretora grande y un canal que conduce la secreción. Cada célula de la unidad secretora contiene un gran lumen y numerosos gránulos secretores, los que están delimitados por una membrana y repletos de un (more) contenido denso a los electrones de aspecto homogéneo, el que es eliminado hacia el lumen. El citoplasma de la célula está repleto de perfiles del retículo endoplasmático granular, de polirribosomas y de aparatos de Golgi. La membrana plasmática basal presenta muchos repliegues cortos hacia el interior y está revestida por una membrana basal fina. La membrana plasmática apical está invaginada para formar el límite del lumen extracelular, lleva microvellosidades cortas y dispersas. Las células son mononucleadas y el núcleo es de forma variada y contiene cromatina dispersa. El lumen está separado del canal de recep