Electrospun bead free silk fibroin biology essay

Fibers with nanoscale diameters supply a benefit because of the high surface area for biomaterial scaffolds. Electrospun silk fibroin-based fibers prepared from aqueous silkworm silk solutions. The ability of electrospun silk matrices to support BMSC attachment, growth and spreading, combined with a biocompatibility and biodegradable properties of the silk protein matrix, result shown suitable biomaterial matrices as scaffolds for tissue engineering [3]. Scaffold configuration, composition, and resulting properties which it is effects into tissue development. The influence of silk fibroin concentration processing method and three-dimensional scaffold structure on bone tissue formation by osteogenic differentiation of human adipose tissue derived stem cells (hASC). It is resulted in a very similar to bone tissue that was formed in all silk fibroin scaffold groups. [4]A silk-fiber matrix studied as a suitable material for tissue engineering anterior cruciate ligaments (ACL). The matrix designed to match the complex and demanding mechanical requirements of a native human ACL, involving adequate fatigue performance. The results support the conclusion that properly prepared silkworm fiber matrices, aside from giving unique benefits in terms of biocompatibility and slow degradability as well as mechanical properties , can provide suitable biomaterial matrices for the support of adult stem cell differentiation toward ligament lineages. These results point toward this matrix as a new option for ACL repair to overcome current limitations with synthetic and other degradable materials. [5] Silk fibroin (SF) and elastin (EL) scaffolds were produced for the first time for the treatment of burn wounds. The self-assembly properties of SF, together with the excellent chemical and mechanical stability and biocompatibility, were combined with elastin protein to produce scaffolds with the ability to mimic the extracellular matrix (ECM). Porous scaffolds were obtained by lyophilization and were further crosslinked with genipin (GE). All results indicated that the composition of the scaffolds had a significant effect on their physical properties, and that can easily be tuned to obtain scaffolds suitable for biological applications. Wound healing was assessed through the use of human full-thickness skin equivalents (EpidermFT. The cytocompatibility demonstrated with human skin fibroblasts together with the healing improvement make these SF/EL scaffolds suitable for wound dressing applications. [6]This study describes the developmental physicochemical properties of silk fibroin scaffolds derived from 26 high-concentration aqueous silk fibroin solutions. The silk fibroin scaffolds were prepared by leaching and freeze- 28 drying methodologies. The results indicated that the antiparallel b-pleated sheet (silk-II) conformation 29 was present in the silk fibroin scaffolds. All the scaffolds possessed a macro/microporous structure. Based on these results, the scaffolds developed in this study are proposed to be suitable 39 for use in meniscus and cartilage tissue-engineered scaffolding. [7] Bone morphogenetic protein (BMP)-2 has a very important role in bone regeneration and formation. So, the ability to immobilize this molecule in certain matrices in bone tissue engineering. Using carbodimide chemistry, BMP-2 was immobilized on silk fibroin films. Whereas human bone marrow stromal cells cultured on unmodified silk fibroin films in the presence of osteogenic stimulants exhibited little if any osteogenesis, the same cells cultured on BMP-2 decorated films in the presence of osteogenic stimulants differentiated into an osteoblastic lineage as assessed by their significantly elevated alkaline phosphatase activity, calcium deposition, and higher transcript levels of collagen type I, bone sialoprotein, osteopontin, osteocalcin, BMP-2, and cbfa1. The results explain that BMP-2 covalently coupled on silk biomaterial matrices retains biological function in vitro based on the induction of osteogenic markers in seeded bone marrow stromal cells.[8] Silks are reassessed as biomaterial scaffolds. We report on the covalent decoration of silk films with integrin recognition sequences (RGD) as well as parathyroid hormone (PTH, 1–34 amino acids) and a modified PTH 1–34 (mPTH) involved in the induction of bone formation. Calcification was also significantly elevated on RGD compared to the other substrates with an increase in number and size of the mineralized nodules in culture. Thus, RGD covalently decorated silk appears to stimulate osteoblast-based mineralization in vitro. [9] This study was to check biocompatibility effect on bone regeneration, and to reform the biocompatibility of the SF Nano fiber membrane. The SF Nano fiber membrane was shown to have a suitable biocompatibility with enhanced bone regeneration and no evidence of any inflammatory reaction. The results shown that the SF membrane very important for bone regeneration and should be useful like guider for bone regeneration.[10] the influence of silk fibroin concentration has an adjusted (6 or 17%) and three-dimensional scaffold structure (lamellar or porous, with distinct pore size) on bone tissue formation by osteogenic differentiation of human adipose tissue derived stem cells (hASC) and correspondent processing method (aqueous or HFIP-derived). The result was shown that very similar bone tissue was formed in all silk fibroin scaffold groups, evaluated by alkaline phosphatase activity, calcium production, collagen type I deposition and scaffold bone volume fraction.[11]A novel biomimetic design of the SF-based nerve graft (SF graft) was developed which was composed of a SF-nerve guidance conduit (NGC) inserted with oriented SF filaments. The examined functional and morphological parameters show that SF grafts could promote peripheral nerve regeneration with effects approaching those produced by nerve auto grafts which are generally considered as the gold standard for treating large peripheral nerve defects, thus raising a potential possibility of using these newly developed nerve grafts as a promising alternative to nerve auto grafts.[12] Rat dorsal root ganglia (DRG) was cultured on the substrate made up of silk fibroin fibers and observed the cell outgrowth from DRG during culture by using light and electron microscopy coupled with immunocytochemistry. On the other hand, we cultured Schwann cells from rat sciatic nerves in the silk fibroin extract fluid and examined the changes of Schwann cells after different times of culture these data indicate that silk fibroin has good biocompatibility with DRG and is also beneficial to the survival of Schwann cells without exerting any significant cytotoxic effects on their phenotype or functions, thus providing an experimental foundation for the development of silk fibroin as a candidate material for nerve tissue engineering applications.[13] Nerve conduits (NC) for peripheral nerve repair should guide the sprouting axons and physically protect the axonal cone from any damage. The NC should also degrade after completion of its function to obviate the need of subsequent explanation and should optionally be suitable for controlled drug release of embedded growth factors to enhance nerve regeneration. Silk fibroin (SF) is a biocompatible and slowly biodegradable biomaterial with excellent mechanical properties that could meet the above stated requirements. SF material (films) supported the adherence and metabolic activity of PC12 cells and in combination with nerve growth factor (NGF), supported neurite outgrowth during PC12 cell differentiation. This study encourages the further exploitation of SF-NC for growth factor delivery and evaluation in peripheral nerve repair. [14]The potential of silk fibroin and chitosan blend (SFCS) biological scaffolds was investigated for the purpose of applications in tracheal tissue reconstruction with cartilage tissue engineering. cartilage generation on engineered chondrocyte–scaffold constructs with and without a perichondrium wrapping was tested and The capability of these scaffolds as cell carrier systems for chondrocytes was determined . Result shown in a tracheal transplant with properties which it is similar to those of the fully functional native trachea. [15]Biodegradable polymer, poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), used to fabricate the tissue engineering as cardiovascular scaffolds because of its suitable mechanical properties and also controllable. Silk fibroin (SF) with no blood clotting, low inflammation and good cell and tissue compatibility in vitro and vivo is adopted as a surface modificator to improve the biocompatibility of PHBHHx. The adhesion of SF on PHBHHx surface was investigated. Silk fibrion modified PHBHHx scaffolds have very good biocompatibility with cardiovascular related cells, that is mean its potential help for the extensive applications of PHBHHx in the cardiovascular regeneration.[16] Cell affinity is one of the important issues required for developing tissue engineering materials. Although the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) has been attractive for its controllable mechanical properties recent years, its cell affinity is still necessary to be improved for the requirements. For this purpose, the regenerated silk fibroin (SF) was coated on the PHBHHx films and its porous scaffolds the SF modified PHBHHx material is maybe a potential material applicable in the cardiovascular tissue engineering.[17] Currently synthetic grafts demonstrate moderate success at the macro vascular level, but fail at the micro vascular scale (<6 mm inner diameter). we report on the development of silk fibroin microtubes for blood vessel repair with several advantages over existing scaffold materials designs. these were prepared by dipping straight lengths stainless steel wire into aqueous fibroin, where addition poly(ethylene oxide) (peo) enabled control microtube porosity. results suggest that microtubes, either implanted directly or preseeded cells, are an attractive biomaterial micro vascular grafts.[18 ] core fibers have a high biocompatibility in vitro and vivo comparable other most commonly used biomaterials such as collagen polylactic acid . well , unique mechanical properties fibers, variety side chain chemistries ‘ decoration’ adhesion factors growth, additional rationale supported genetically tailor protein provide exploration this family fibrous proteins applications. studies about silks to address matrix focused silkworm silk. silk-like from spiders insects, range native bioengineered variants can be expected application different junctions clinical needs. [19]color dye-doped nanoparticles fabricated using emulsion method. yielding color nanoparticles, 167 nm diameter. secondary structure showed β-sheet conformation. size distribution measured, morphology was determined. observed stability loaded fluorescent molecules it new important devices molecular imaging bioassays. slow degradation combined its biocompatibility, because nano-scale size, their capacity encapsulate dye, they may great impact more use various biological [20] obtaining microspheres submicronic particles spray dryer method developed completed transition random coil b-sheet during treatment. defined ph sfmp_s swelling ratio is dependent solution, not occurred gelation. morphologically, sfmp spherical shape, particles, average 2 _ 10 lm size. characteristic might applied immobilization drugs. would skin affinity, superior [21] cross-linked non-cross-linked (sf) simple water-in-oil solvent diffusion studied. sf microparticles shape smooth surface. microsphere sizes found depend upon process parameters. both genipin-cross-linked contained porous structures.. genipin cross-linking induced conformational form but change. suitable microcarriers hydrophilic drug delivery.[22]a novel solution-enhanced dispersion supercritical co2 (seds) employed prepare nanoparticles. resulting exhibited surface, narrow particle mean diameter approximately 50 before after ethanol treatment indicated conformation thus water insolubilityimposed no toxicity. (indomethacin) idmc–sf significantly sustained release days. shown suitability seds biocompatible carrier deliver drugs also feasibility arrive goal co-precipitation composite controlled delivery. [23]biologically derived (100 nm) local therapeutic curcumin delivery cancer cells. sf-derived show higher efficacy against breast cells potential treat tumors local, sustained, long-term biodegradable system. [24] biologically systems offer promise regard owing minimization adverse effects while increasing entrapped therapeutic. overcome barriers set synthetic non degradable made silicone, polyethylene glycol acid–polyglycolic polymers. fibroin-mediated has demonstrated targeting associated specificity diseased fibroin-derived enhance intracellular uptake retention down modulation than one pathway due longer availability mechanism nanoparticle based composition, self-assembly b-barrels. [25]drug-loaded spheres without diglycidyl ether (pegde) crosslinking homogenizing speed pegde characteristics behaviors suggested desired profiles design adjusting ratio. [26] conjugated methoxypoly(ethylene glycol) derivatives nanoparicles. conjugation peg examined instrumental analyses. nuclear magnetic resonance spectrometry amino analysis serine tyrosine residues reacted resulted weight. shapes transmission electronmicroscope ranged 150-400 morphology. uv vis outer structure. [27] proof-of-concept study fabrication drug-loaded under very mild processing conditions. laminar jet break-up which nozzle vibrating at frequency amplitude. determined sem diameters 101 µm 440 µm, depending induce sf. favor further investigation platform sensitive biologicals. [28]the objective present investigate possibility preparing pure regenerated (rsf). rsf microspheres, predictable controllable ranging 0. 1. 5 via self-assembling chains. greatly affected amount additive, freezing temperature concentration fibroin. finally, formation discussed our experimental results.[29]we investigated pharmaceutical utility possible separation, sephadex g-25 gel filtration chromatography simply (sfmp) dryer. also, some physicochemical investigated. accelerated identified basic fourier transform infrared spectroscopy sfmp. sfmps gelation.. weight (mw) dissolved calcium chloride 61, 500 g mol measured permeation chromatography.[30] work application. tailored ratio.[31] films solutions polymer crystallinity methanol dextrans weights, proteins, physically device films. kinetics evaluated function dextran weight, film crystallinity. conclusion, interesting polysaccharides bioactive level ability fashion ambient conditions avoid damage labile compounds delivered. [32] fluorescein-iso-thio-cyanate (fitc)-labeled methanol-treated untreated modeled characterize mechanisms. linear regression fit relationship between percent fitc-dextran particles. relationships, updated version model simulating varied weights [33]

Films

Robust ultrathin multilayer films of silk fibroin were fabricated by spin coating and spin-assisted layer-by-layer assembly and their mechanical properties were studied both in tensile and compression modes. The superior toughness is many times higher than that usually observed for usual polymer composites. These exceptional properties are caused by the highly crystalline b-sheets, serving as reinforcing Fillers and physical crosslinks, a process that is well known for bulk silk materials but it is shown here to occur in ultrathin Films as well, even with their limited dimensions. However, the confined state within films thinner than the lengths of the extended domains causes a significantly reduced elasticity which should be considered in the design of nanosized films from silk Materials. Such regenerated silk fibroin films with exceptional mechanical strength have potential applications in microscale Biodevices, biocompatible implants, and synthetic coatings for artificial skin. [34]