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posted Mar 4, 2011, 8:38 AM by rajesh gk

Title

Application of recombinant fusion proteins for tissue engineering.

Authors

Nagaoka M, Jiang HL, Hoshiba T, Akaike T, Cho CS.

Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.

Journal

Ann Biomed Eng. 2010 Mar;38(3):683-93. Epub 2010 Feb 4.

Abstract

Extracellular matrix (ECM) plays important roles in tissue engineering because cellular growth and differentiation, in the two-dimensional cell culture as well as in the three-dimensional space of the developing organism, require ECM with which the cells can interact. Also, the development of new synthetic ECMs is very important because ECMs facilitate the localization and delivery of cells to the specific sites in the body. Therefore, the development of synthetic ECMs to replace the natural ECMs is increasingly essential and promising in tissue engineering. Recombinant genetic engineering method has enabled the synthesis of protein-based polymers with precisely controlled functionalities for the development of new synthetic ECMs. In this review, the design and construction of structure-based recombinant fusion proteins such as elastin-like polymers (ELPs) and silk-like polymers (SLPs), cell-bound growth factor-based recombinant fusion proteins such as basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF), hybrid system composed of recombinant protein and synthetic polymer, and E-cadherin-based fusion protein by recombinant genetic engineering were explained for application of the synthetic ECMs. Modulation of mechanical properties, stimuli-sensitivity, biodegradation and cell recognition can be achieved through precise control of sequence, length, hydrophobicity and cell binding domain by recombinant genetic engineering.

Citation

http://www.ncbi.nlm.nih.gov/pubmed/20131097 PMID: 20131097 [PubMed - indexed for MEDLINE]

 

Title

Animal silks: their structures, properties and artificial production.

Authors

Fu C, Shao Z, Fritz V.

Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Advanced Materials Laboratory, Department of Macromolecular Science, Fudan University, Shanghai 200433, PR China.

Journal

Chem Commun (Camb). 2009 Nov 21;(43):6515-29. Epub 2009 Sep 8.

Abstract

This feature article reviews recent progress in the understanding of the hierarchically organized structures, the perfectly balanced mechanical properties and the structure-property relationship of the natural animal silk fibres, as well as the experimental attempts to fabricate man-made silk fibres by means of wet spinning, dry spinning, electrospinning and transgenosis.

Citation

http://www.ncbi.nlm.nih.gov/pubmed/19865641 PMID: 19865641 [PubMed - indexed for MEDLINE]

 

Title

The effect of sericin from various extraction methods on cell viability and collagen production. Free PMC Article

Authors

Aramwit P, Kanokpanont S, Nakpheng T, Srichana T.

Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.

 

Journal

Int J Mol Sci. 2010 May 20;11(5):2200-11.

 

Abstract

Silk sericin (SS) can accelerate cell proliferation and attachment; however, SS can be extracted by various methods, which result in SS exhibiting different physical and biological properties. We found that SS produced from various extraction methods has different molecular weights, zeta potential, particle size and amino acid content. The MTT assay indicated that SS from all extraction methods had no toxicity to mouse fibroblast cells at concentrations up to 40 mug/mL after 24 h incubation, but SS obtained from some extraction methods can be toxic at higher concentrations. Heat-degraded SS was the least toxic to cells and activated the highest collagen production, while urea-extracted SS showed the lowest cell viability and collagen production. SS from urea extraction was severely harmful to cells at concentrations higher than 100 mug/mL. SS from all extraction methods could still promote collagen production in a concentration-dependent manner, even at high concentrations that are toxic to cells.

Citation

http://www.ncbi.nlm.nih.gov/pubmed/20559510 PMID: 20559510 [PubMed - in process]PMCID: PMC2885102

 

 

Title

Low molecular weight silk fibroin increases alkaline phosphatase and type I collagen expression in MG63 cells.

Authors

Kim JY, Choi JY, Jeong JH, Jang ES, Kim AS, Kim SG, Kweon HY, Jo YY, Yeo JH.

Department of Oral and Maxillofacial Surgery, Hallym University, Chuncheon 200-702, Korea.

Journal

BMB Rep. 2010 Jan;43(1):52-6.

Abstract

Silk fibroin, produced by the silkworm Bombyx mori, has been widely studied as a scaffold in tissue engineering. Although it has been shown to be slowly biodegradable, cellular responses to degraded silk fibroin fragments are largely unknown. In this study, silk fibroin was added to MG-63 cell cultures, and changes in gene expression in the MG-63 cells were screened by DNA microarray analysis. Genes showing a significant (2-fold) change were selected and their expression changes confirmed by quantitative RT-PCR and western blotting. DNA microarray results showed that alkaline phosphatase (ALP), collagen type-I alpha-1, fibronectin, and transforming growth factor-beta1 expressions significantly increased. The effect of degraded silk fibroin on osteoblastogenic gene expression was confirmed by observing up-regulation of ALP activity in MG-63 cells. The finding that small fragments of silk fibroin are able to increase the expression of osteoblastogenic genes suggests that controlled degradation of silk fibroin might accelerate new bone formation. [BMB reports 2010; 43(1): 52-56].

Citation

PMID: 20132736 [PubMed - indexed for MEDLINE] Free Article

 

Title

Biodegradation of silk biomaterials. Free PMC Article

Authors

Cao Y, Wang B.

Jiangsu University of Science and Technology, Zhenjiang Jiangsu, P R China. bestmancy@163.com

Journal

Int J Mol Sci. 2009 Mar 31;10(4):1514-24.

Abstract

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.

Citation

PMID: 19468322 [PubMed]PMCID: PMC2680630Free PMC Article

 

Title

Enhancing effects of sericin on corneal wound healing in rat debrided corneal epithelium. Free Article

Authors

Nagai N, Murao T, Ito Y, Okamoto N, Sasaki M.

School of Pharmacy, Kinki University, Osaka, Japan.

Journal

Biol Pharm Bull. 2009 May;32(5):933-6.

Abstract

The protein sericin is the main constituent of silk. We demonstrate the effects of sericin on corneal wound healing in rat debrided corneal epithelium. We also determined the effects of sericin on cell adhesion and proliferation in a human cornea epithelial cell line (HCE-T). Epithelium was removed from the corneas of rats with a BD Micro-Sharp, and wounded corneas were dyed with a 1% fluorescein solution. The corneal wounds were monitored using a fundus camera TRC-50X equipped with a digital camera. The corneal wound of rats instilled with saline was approximately 10% healing at 12 h, and approximately 65% healing at 24 h after corneal epithelial abrasion. The corneal wounds of rats instilled with saline showed almost complete healing by 36 h after corneal epithelial abrasion. On the other hand, the corneal healing rate of rats instilled with sericin solution was higher than that of rats instilled with saline, and the corneal healing rate constant increased with increasing sericin concentration. In addition, the adhesion and proliferation of HCE-T cells treated with 0.01-0.5% sericin solutions were enhanced, reaching a maximum at treatments with 0.2 and 0.1% sericin solutions, respectively. The present study demonstrates that the instillation of sericin solution has a potent effect in promoting wound healing and wound-size reduction in rats, probably caused by increasing cell movement and proliferation.

Citation

PMID: 19420767 [PubMed - indexed for MEDLINE]

 

Title

Biomedical applications of chemically-modified silk fibroin.

Authors

Murphy AR, Kaplan DL.

Department of Biomedical Engineering, 4 Colby Street, Tufts University, Medford, MA 02155. Email: david.kaplan@tufts.edu.

Journal

J Mater Chem. 2009 Jun 23;19(36):6443-6450.

Abstract

Silk proteins belong to a class of unique, high molecular weight, block copolymer-like proteins that have found widespread use in biomaterials and regenerative medicine. The useful features of these proteins, including self-assembly, robust mechanical properties, biocompatibility and biodegradability can be enhanced through a variety of chemical modifications. These modifications provide chemical handles for the attachment of growth factors, cell binding domains and other polymers to silk, expanding the range of cell and tissue engineering applications attainable. This review focuses on the chemical reactions that have been used to modify the amino acids in silk proteins, and describes their utility in biomedical applications.

Citation

PMID: 20161439 [PubMed]PMCID: PMC2790051 Free PMC Article

 

 

Title

Silk-based materials for biomedical applications.

Authors

Leal-Egaña A, Scheibel T.

Lehrstuhl für Biomaterialien, Fakultät für Angewandte Naturwissenschaften, Universität Bayreuth, 95440 Bayreuth, Germany.

Journal

Biotechnol Appl Biochem. 2010 Mar 12;55(3):155-67.

Abstract

Since the beginning of civilization, humans have exploited nature as an extraordinary source of materials for medical applications. Most natural materials comprise biopolymers such as nucleic acids and protein-polysaccharides. For biomedical applications, proteins such as collagens have been traditionally employed. Other proteins are silk fibres produced by arthropods (e.g. silkworms and spiders), which provide interesting mechanical properties and the absence of toxicity. Silks present almost all characteristics desirable for biomedical applications, but the research on the underlying proteins has only recently commenced. In the present review, we summarize the current research related to silk being used as a material for cell culture and tissue engineering, particularly focusing on cell-surface adherence, mechanical and textural properties, toxicity, immunogenicity and biodegradability.

Citation

PMID: 20222871 [PubMed - indexed for MEDLINE]

 

Title

The silk proteins, sericin and fibroin in silkworm, Bombyx mori Linn., - a review

Authors

Mondal, M.*, Trivedy, K., Nirmal Kumar, S.,

Journal

Caspian J. Env. Sci., 5, 63-76. ( 2007 )

Abstract

The domesticated silkworm, Bombyx mori Linn., a lepidopteran molecular model and an important economic insect that are emerging as an ideal molecular genetic resource for solving a broad range of biological problems. The silkworm, B. mori produces massive amount of silk proteins during the final stage of larval development. These proteins are stored in the middle silk gland and they are discharged through the anterior duct and spinneret, at the end of the fifth instar. Two kinds of silk proteins have been distinguished as major components of silk cocoons, the first being fibroin, a fibrous protein composed of heavy (H) chain, Light (L) chain and glycoprotein linked by disulfide bonds and the second being sericin a natural macromolecular protein, serving as an adhesive to unite fibroin for making silk cocoons of silkworm, B. mori. Recently, silkworm is being used as biofactory for the production of useful protein using the silk gland, which has promoted the technological development in sericulture. With the above background silkworm can be classified as a value added biomaterial for medical application, application of silk protein fibroin and sericin as a biomaterial and other seri-byproducts. The present paper overviews some important studies carried out on sericin and fibroin of silkworm, Bombyx mori Linn.

Citation

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Title

Silk Fibroin Based Porous Materials

Authors

Qiang Zhang ; Shuqin Yan ; Mingzhong Li

Journal

Materials, 2009; 2(4)

Abstract

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.

Citation

FULL TEXT

 

Title

Silk film biomaterials for cornea tissue engineering.

Authors

Lawrence BD, Marchant JK, Pindrus MA, Omenetto FG, Kaplan DL.

Department of Biomedical Engineering, Tufts University, 4 Colby St., Medford, MA 02155, USA.

Journal

Biomaterials. 2009 Mar;30(7):1299-308. Epub 2008 Dec 6.

Abstract

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

Citation

PMID: 19059642 [PubMed - indexed for MEDLINE]PMCID: PMC2670567 Free PMC Article

 

Title

Silk: a potential medium for tissue engineering.

Authors

Sobajo C, Behzad F, Yuan XF, Bayat A.

Plastic & Reconstructive Surgery Research, Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, M1 7DN, UK.

Journal

Eplasty. 2008;8:e47. Epub 2008 Oct 10.

Abstract

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

Citation

PMID: 18997857 [PubMed]PMCID: PMC2567119 Free PMC Article

 

Title

Protective effect of sericin peptide against alcohol-induced gastric injury in mice.

Authors

Li YG, Ji DF, Lin TB, Zhong S, Hu GY, Chen S.

Sericultural Research Institute, Zhejiang Academy of Agricultural Science, Hangzhou, Zhejiang 310021, China.

Journal

Chin Med J (Engl). 2008 Oct 20;121(20):2083-7.

Abstract

BACKGROUND: Sericin peptide (SP) has shown a powerful anti-oxidant property in a host of studies. The present study was designed to investigate the possible protective effects of SP against alcohol-induced gastric lesions in mice and to explore the potential mechanisms. METHODS: Animals were randomly divided into 5 groups: control, alcohol (56%, 14.2 ml/kg), SP-treated mice (0.2, 0.4, 0.8 g/kg). Mice were pretreated with SP before administering alcohol, the concentration of ethanol in serum and urine, the contents of malondialdehyde (MDA), glutathione (GSH) and the glutathione peroxidase (GSH-PX), catalase (CAT) and superoxide dismutase (SOD) activities in the gastric mucosa were measured, subsequently, the pathological evaluation of stomach was also observed. RESULTS: Of the animals pre-treated with SP (0.4, 0.8 g/kg), the concentration of ethanol in serum was significantly decreased, while increased in urine as compared to the alcohol-administered alone animals. Alcohol administration caused severe gastric damage as indicated by markedly increased MDA levels and decreased antioxidants, such as reduced GSH, GSH-PX and SOD in the gastric tissue while the CAT activity was not altered. On SP administration there was a reversal in these values towards normal. Histopathological studies confirmed the beneficial role of SP, which was in accordance with the biochemical parameters. CONCLUSIONS: SP could protect gastric mucosa from alcohol-induced mucosal injury. These gastroprotective effects might be due to increasing 'first-pass metabolism' in the stomach and hastening ethanol elimination directly through the urine. SP might also play an important role in the protection of the structure and function of gastric mitochondria, at least partly based on their anti-oxidant effect.

Citation

PMID: 19080280 [PubMed - indexed for MEDLINE] Free Article

 

Title

Preparation of gel film from Bombyx mori silk sericin and its characterization as a wound dressing.

Authors

Teramoto H, Kameda T, Tamada Y.

Division of Insect Sciences, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan. teramoto@affrc.go.jp

Journal

Biosci Biotechnol Biochem. 2008 Dec;72(12):3189-96. Epub 2008 Dec 7.

Abstract

Sericin is a highly hydrophilic protein family acting as the glue in Bombyx mori silk. In order to apply sericin as a wound dressing, a novel sericin film named gel film was prepared by a simple process without using any chemical modifications: sericin solution was gelled with ethanol into a sheet shape and then dried. Infrared analysis revealed that the sericin gel film contained water-stable beta-sheet networks formed in the gelation step. This structural feature rendered the gel film morphologically stable against swelling and gave it good handling properties in the wet state. The sericin gel film rapidly absorbed water, equilibrating at a water content of about 80%, and exhibited elastic deformation up to a strain of about 25% in the wet state. A culture of mouse fibroblasts on the gel film indicated that it had low cell adhesion properties and no cytotoxicity. These characteristics of sericin gel film suggest its potential as a wound dressing.

Citation

PMID: 19060395 [PubMed - indexed for MEDLINE] Free Article

 

Title

Peptide-based Biopolymers in Biomedicine and Biotechnology.

Authors

Chow D, Nunalee ML, Lim DW, Simnick AJ, Chilkoti A.

Department of Biomedical Engineering, Duke University, Box 90281, Durham, North Carolina 27708-0281.

Journal

Mater Sci Eng R Rep. 2008 Jan;62(4):125-155.

Abstract

Peptides are emerging as a new class of biomaterials due to their unique chemical, physical, and biological properties. The development of peptide-based biomaterials is driven by the convergence of protein engineering and macromolecular self-assembly. This review covers the basic principles, applications, and prospects of peptide-based biomaterials. We focus on both chemically synthesized and genetically encoded peptides, including poly-amino acids, elastin-like polypeptides, silk-like polymers and other biopolymers based on repetitive peptide motifs. Applications of these engineered biomolecules in protein purification, controlled drug delivery, tissue engineering, and biosurface engineering are discussed.

Citation

PMID: 19122836 [PubMed]PMCID: PMC2575411 Free PMC Article

 

Title

Biofunctionalized electrospun silk mats as a topical bioactive dressing for accelerated wound healing.

Authors

Schneider A, Wang XY, Kaplan DL, Garlick JA, Egles C.

Division of Cancer Biology and Tissue Engineering, Department of Oral and Maxillofacial Pathology, Tufts University, School of Dental Medicine, 55 Kneeland Street, Boston, MA 02111, USA.

Journal

Acta Biomater. 2009 Sep;5(7):2570-8. Epub 2008 Dec 31.

Abstract

Materials able to deliver topically bioactive molecules represent a new generation of biomaterials. In this article, we describe the use of silk mats, made of electrospun nanoscale silk fibers containing epidermal growth factor (EGF), for the promotion of wound healing processes. In our experiments, we demonstrated that EGF is incorporated into the silk mats and slowly released in a time-dependent manner (25% EGF release in 170h). We tested these materials using a new model of wounded human skin-equivalents displaying the same structure as human skin and able to heal using the same molecular and cellular mechanisms found in vivo. This human three-dimensional model allows us to demonstrate that the biofunctionalized silk mats, when placed on the wounds as a dressing, aid the healing by increasing the time of wound closure by the epidermal tongue by 90%. The preservation of the structure of the mats during the healing period as demonstrated by electronic microscopy, the biological action of the dressing, as well as the biocompatibility of the silk demonstrate that this biomaterial is a new and very promising material for medical applications, especially for patients suffering from chronic wounds.

Citation

PMID: 19162575 [PubMed - indexed for MEDLINE]PMCID: PMC2810481 Free PMC article

 

posted Jul 5, 2010, 2:04 AM by rajesh gk

Title

Interaction of recombinant analogs of spider silk proteins 1F9 and 2E12 with p hospholipid membranes.

Authors

Antonenko YN, Perevoshchikova IV, Davydova LI, Agapov IA, Bogush VG.

 

A.N.Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia. antonen@genebee.msu.ru

Journal

Biochim Biophys Acta. 2010 Jun;1798(6):1172-8. Epub 2010 Mar 7.

Abstract

Recombinant analogs of spider dragline silk proteins 1F9 and 2E12 are characterized by numerous repeats consisting of hydrophobic poly-Ala blocks and Gly-rich sequences with a substantial number of positively charged amino acid residues which suggest a pronounced ability to interact with negatively charged phospholipid membranes. Actually both proteins displayed substantial binding affinity towards lipid vesicles formed of acidic lipids as measured by fluorescence correlation spectroscopy (FCS) using rhodamine-labeled conjugates of the proteins. Both proteins did not induce liposome leakage, fusion or breakdown, but were able to bring about liposome aggregation. 1F9 was more active in the induction of liposome aggregation compared to 2E12. Interestingly, 2E12 markedly decreased the rate of calcium-induced liposome fusion. Circular dichroism data showed that binding of the proteins to negatively charged phosphatidylserine liposomes provoked transition from the left-handed helix of polyproline II (PPII) type to beta-structures and alpha-helices. The data suggested predominantly surface location of membrane bound proteins without significant perturbation of their hydrophobic core.

Citation

PMID: 20214876 [PubMed - indexed for MEDLINE]

 

Title

Morphology and tensile properties of silk fibers produced by uncommon Saturniidae.

Authors

Reddy N, Yang Y.

 

Department of Textiles, University of Nebraska-Lincoln, 68583-0802, United States.

Journal

Int J Biol Macromol. 2010 May 1;46(4):419-24. Epub 2010 Mar 6.

Abstract

Silk fibers produced by undomesticated wild insects belonging to the Saturniidae family have unique properties compared to the commonly used silks. Insects belonging to the Saturniidae family are one of the largest moths found throughout the world, produce large cocoons and are easier to rear than B. mori. In this research, we have characterized the morphology and tensile properties of silks produced by eight wild insects that belong to the Saturniidae family. Fibers produced by Saturniidae insects such as C. hercuels have properties similar to that of B. mori silk whereas fibers produced by Copaxa multifenestrata have inferior properties than B. mori or the common wild silks. In addition, the tensile properties of the fibers vary considerably between insects. Fibers with fineness ranging from 1.5 to 7.8denier and breaking tenacity ranging from 0.9 to 5g per denier are produced by the Saturniidae insects. Identifying the unique properties of Saturniidae silks such as tensile properties, yield of silk from the cocoons and ability to grow under different environments will help to evaluate the potential of rearing the wild insects for commercial production of silk for textile, medical and other applications. 2010 Elsevier B.V. All rights reserved.

Citation

PMID: 20211646 [PubMed - indexed for MEDLINE]

 

Title

Mulberry Diels-Alder adducts: synthesis of chalcomoracin and mulberrofuran C methyl ethers.

Authors

Gunawan C, Rizzacasa MA.

 

School of Chemistry, The Bio21 Institute, The University of Melbourne, Victoria 3010, Australia.

Journal

Org Lett. 2010 Apr 2;12(7):1388-91.

Abstract

The synthesis of each of the heptamethyl ethers of the mulberry Diels-Alder adducts chalcomoracin (1) and mulberrofuran J (2) is described. The key steps in each approach involved a biomimetic intermolecular [4+2]-cycloaddition between a dehydroprenylphenol diene derived from an isoprenoid-substituted phenolic compound and an alpha,beta-unsaturated alkene of a chalcone as the dienophile. Critical to the success of the Diels-Alder reaction was the presence of the free phenol in the 2'-hydroxychalcone.

Citation

PMID: 20196580 [PubMed - indexed for MEDLINE]

 

Title

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

Authors

Wang X, Sun L, Maffini MV, Soto A, Sonnenschein C, Kaplan DL.

 

Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA.

Journal

Biomaterials. 2010 May;31(14):3920-9. Epub 2010 Feb 24.

Abstract

Epithelial-stromal interactions play a crucial role in normal embryonic development and carcinogenesis of the human breast while the underlying mechanisms of these events remain poorly understood. To address this issue, we constructed a physiologically relevant, three-dimensional (3D) culture surrogate of complex human breast tissue that included a tri-culture system made up of human mammary epithelial cells (MCF10A), human fibroblasts and adipocytes, i.e., the two dominant breast stromal cell types, in a Matrigel/collagen mixture on porous silk protein scaffolds. The presence of stromal cells inhibited MCF10A cell proliferation and induced both alveolar and ductal morphogenesis and enhanced casein expression. In contrast to the immature polarity exhibited by co-cultures with either fibroblasts or adipocytes, the alveolar structures formed by the tri-cultures exhibited proper polarity similar to that observed in breast tissue in vivo. Only alveolar structures with reverted polarity were observed in MCF10A monocultures. Consistent with their phenotypic appearance, more functional differentiation of epithelial cells was also observed in the tri-cultures, where casein alpha- and -beta mRNA expression was significantly increased. This in vitro tri-culture breast tissue system sustained on silk scaffold effectively represents a more physiologically relevant 3D microenvironment for mammary epithelial cells and stromal cells than either co-cultures or monocultures. This experimental model provides an important first step for bioengineering an informative human breast tissue system, with which to study normal breast morphogenesis and neoplastic transformation. Copyright 2010 Elsevier Ltd. All rights reserved.

Citation

PMCID: PMC2847607 [Available on 2011/5/1] ,PMID: 20185172 [PubMed - indexed for MEDLINE]

 

Title

Application of recombinant fusion proteins for tissue engineering.

Authors

Nagaoka M, Jiang HL, Hoshiba T, Akaike T, Cho CS.

 

Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.

Journal

Ann Biomed Eng. 2010 Mar;38(3):683-93. Epub 2010 Feb 4.

Abstract

Extracellular matrix (ECM) plays important roles in tissue engineering because cellular growth and differentiation, in the two-dimensional cell culture as well as in the three-dimensional space of the developing organism, require ECM with which the cells can interact. Also, the development of new synthetic ECMs is very important because ECMs facilitate the localization and delivery of cells to the specific sites in the body. Therefore, the development of synthetic ECMs to replace the natural ECMs is increasingly essential and promising in tissue engineering. Recombinant genetic engineering method has enabled the synthesis of protein-based polymers with precisely controlled functionalities for the development of new synthetic ECMs. In this review, the design and construction of structure-based recombinant fusion proteins such as elastin-like polymers (ELPs) and silk-like polymers (SLPs), cell-bound growth factor-based recombinant fusion proteins such as basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF), hybrid system composed of recombinant protein and synthetic polymer, and E-cadherin-based fusion protein by recombinant genetic engineering were explained for application of the synthetic ECMs. Modulation of mechanical properties, stimuli-sensitivity, biodegradation and cell recognition can be achieved through precise control of sequence, length, hydrophobicity and cell binding domain by recombinant genetic engineering.

Citation

PMID: 20131097 [PubMed - indexed for MEDLINE]

 

Title

Recombinant silk-elastinlike protein polymer displays elasticity comparable to elastin.

Authors

Teng W, Cappello J, Wu X.

 

Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona 85721, USA.

Journal

Biomacromolecules. 2009 Nov 9;10(11):3028-36.

Abstract

We evaluated the mechanical properties of the genetically engineered, recombinant silk-elastinlike protein copolymer, SELP-47K. In tensile stress-strain analysis, methanol-treated non-cross-linked SELP-47K films exceeded the properties of native aortic elastin, attaining an ultimate tensile strength of 2.5 +/- 0.4 MPa, an elastic modulus of 1.7 +/- 0.4 MPa, an extensibility of 190 +/- 60%, and a resilience of 86 +/- 4% after 10 cycles of mechanical preconditioning. Stress-relaxation and creep analysis showed that films substantially maintained their elastic properties under sustained deformation. Chemical cross-linking of SELP-47K films doubled the elastic modulus and ultimate tensile strength and enhanced the extensibility and resilience. The underlying conformational and microstructural features of the films were examined. Raman spectroscopy revealed that the silklike blocks of SELP-47K existed in antiparallel beta-sheet crystals in the films, likely responsible for the robust physical cross-links. Scanning electron microscopy (SEM) revealed that the various processing treatments and the mechanical deformation of the films induced changes in their surface microstructure consistent with the coagulation and alignment of polymer chains. These results demonstrate that films with excellent elasticity, comparable to native aortic elastin, are obtainable from SELP-47K, a protein copolymer combining both silk- and elastin-derived sequences in a single polymer chain.

Citation

PMID: 19788307 [PubMed - indexed for MEDLINE]

 

Title

Surface modification of silk fibroin with poly(ethylene glycol) for antiadhesion and antithrombot ic applications.

Authors

Vepari C, Matheson D, Drummy L, Naik R, Kaplan DL.

 

Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts 02155, USA.

Journal

J Biomed Mater Res A. 2010 May;93(2):595-606.

Abstract

Silk fibroin film surfaces were PEGylated by reaction with cyanuric chloride-activated poly(ethylene glycol) (PEG). Reactions with different concentrations of activated PEG generated films with PEG graft densities from 0.02 to 0.4 mg per square cm of silk fibroin. Increased PEGylation resulted in increased hydrophilicity as analyzed by contact angle, and a smoother morphology based on scanning electron microscopy. Increased PEGylation decreased human IgG adsorption and decreased the attachment and proliferation of human fibroblasts over two weeks. Increased concentration of PEG on the silk fibroin surfaces also decreased the proliferation of human mesenchymal stem cells and inhibited human platelet attachment. Surface PEGylated silk fibroin films could be useful antiadhesion and antithrombotic materials for biomedical applications when considered along with the unique mechanical and tailorable degradation profiles of silk fibroin. Copyright 2009 Wiley Periodicals, Inc.

Citation

PMID: 19591236 [PubMed - indexed for MEDLINE]

 

Title

Morphology and tensile properties of silk fibers produced by uncommon Saturniidae.

Authors

Reddy N, Yang Y.

 

Department of Textiles, University of Nebraska-Lincoln, 68583-0802, United States.

Journal

Int J Biol Macromol. 2010 May 1;46(4):419-24. Epub 2010 Mar 6.

Abstract

Silk fibers produced by undomesticated wild insects belonging to the Saturniidae family have unique properties compared to the commonly used silks. Insects belonging to the Saturniidae family are one of the largest moths found throughout the world, produce large cocoons and are easier to rear than B. mori. In this research, we have characterized the morphology and tensile properties of silks produced by eight wild insects that belong to the Saturniidae family. Fibers produced by Saturniidae insects such as C. hercuels have properties similar to that of B. mori silk whereas fibers produced by Copaxa multifenestrata have inferior properties than B. mori or the common wild silks. In addition, the tensile properties of the fibers vary considerably between insects. Fibers with fineness ranging from 1.5 to 7.8denier and breaking tenacity ranging from 0.9 to 5g per denier are produced by the Saturniidae insects. Identifying the unique properties of Saturniidae silks such as tensile properties, yield of silk from the cocoons and ability to grow under different environments will help to evaluate the potential of rearing the wild insects for commercial production of silk for textile, medical and other applications. 2010 Elsevier B.V. All rights reserved.

Citation

PMID: 20211646 [PubMed - indexed for MEDLINE]

 

Title

Hierarchical, multilayered cell walls reinforced by recycled silk cocoons enhance the structural integrity of honeybee combs.

Authors

Zhang K, Duan H, Karihaloo BL, Wang J.

 

State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871, China. KarihalooB@cardiff.ac.uk

Journal

Proc Natl Acad Sci U S A. 2010 May 25;107(21):9502-6. Epub 2010 May 3.

Abstract

We reveal the sophisticated and hierarchical structure of honeybee combs and measure the elastic properties of fresh and old natural honeycombs at different scales by optical microscope, environmental scanning electron microscope, nano/microindentation, and by tension and shear tests. We demonstrate that the comb walls are continuously strengthened and stiffened without becoming fragile by the addition of thin wax layers reinforced by recycled silk cocoons reminiscent of modern fiber-reinforced composite laminates. This is done to increase its margin of safety against collapse due to a temperature increase. Artificial engineering honeycombs mimic only the macroscopic geometry of natural honeycombs, but have yet to achieve the microstructural sophistication of their natural counterparts. The natural honeycombs serve as a prototype of truly biomimetic cellular materials with hitherto unattainable improvement in stiffness, strength, toughness, and thermal stability.

Citation

PMID: 20439765 [PubMed - indexed for MEDLINE]

 

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