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Tissue-engineered skin with mechanical and biological properties that match the native tissue could be a valuable graft to treat non-healing chronic wounds. Fibroblasts grown on a suitable biodegradable scaffold are a feasible strategy for the development of a dermal substitute above which epithelialization may occur naturally. Cell growth and phenotype maintenance are crucial to ensure the functional status of engineered tissue. In this study, an electrospun biodegradable polymer scaffold composed of a terpolymer PLGC [poly(lactide-glycolide-caprolactone)] with appropriate mechanical strength was used as a scaffold so that undesirable contraction of the wound could be prevented when it was implanted. To enhance cell growth, synthetic PLGC was incorporated with a fibrin-based biomimetic composite. The efficacy of the hybrid scaffold was evaluated by comparing it with bare PLGC in terms of fibroblast growth potential, extracellular matrix (ECM) deposition, polymer degradation, and mechanical strength. A significant increase was observed in fibroblast attachment, proliferation, and deposition of ECM proteins such as collagen and elastin in the hybrid scaffold. After growing fibroblasts for 20 d and 40 d, immunochemical staining of the decellularized scaffolds showed deposition of insoluble collagen and elastin on the hybrid scaffold but not on the bare scaffold. The loss of mechanical strength consequent to in vitro polymer degradation seemed to be balanced owing to the ECM deposition. Thus, tensile strength and elongation were better when cells were grown on the hybrid scaffold rather than the bare samples immersed in culture medium. Similar patterns of in vivo and in vitro degradation were observed during subcutaneous implantation and fibroblast culture, respectively. We therefore postulate that a hybrid scaffold comprising PLGC and fibrin is a potential candidate for the engineering of dermal tissue to be used in the regeneration of chronic wounds.

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A replaceable wound cover which absorbs moisture and resist infection can be used to prevent development of chronic wounds. A major criterion for a replaceable wound dressing is nonadherence to cells to prevent pain upon removal. A major limitation of water absorbing hydrogels used in wound dressing applications is their poor mechanical strength. In this study, gelatin methacrylate (GelMA) was synthesized by reacting Type A porcine skin gelatin with methacrylic anhydride at 50 8C. Resultant GelMA monomer containing polyethylene glycol (PEG) protected silver nanoparticles were subsequently copolymerized with 2-hydroxypropyl methacrylate (HPMA) at room temperature by redox mechanism. This resulted in a hydrogel copolymer with optimum mechanical stability and moisture retention while inhibiting microbial contamination and FT-IR spectroscopy was used to confirm copolymer formation. Antimicrobial properties of the hydrogel using agar diffusion showed zone of inhibition against Staphylococcus aureus. Surface morphology was observed using scanning electron microscopy (SEM) and elemental analysis was carried out using energydispersive spectroscopy (EDS). Micro-computed tomography (micro-CT) analysis of the hydrogel showed enhancement in the pore size from around 32 m to 48-64 m after incorporation of silver nanoparticles. Degradation of the hydrogel was observed after 48 h when stored in PBS containing collagenase enzyme. In vitro cell culture experiments established absence of cytotoxicity in the hydrogel and nonadherence character to dermal fibroblasts.

Concentration of camphorquinone initiator, exposure time of the light source and particle size of a radiopaque glass filler have been varied for an indigenously developed light-curing dental composite and the changes in the microhardness, compressive strength and diametral tensile strength studied. Higher initiator concentration and exposure times are found to improve the microhardness values while a concentration above 0.25% does not signify any drastic improvement in compressive and diametral strength. Changes in properties are found to be statistically significant at low initiator concentrations. A filler particle size around 1 microm is found to give better properties compared with larger sizes.