Preparation And Properties Of Novel Collagen Dermal Scaffold Material

Human skin is a soft outer covering of the body, which plays a key role in protecting the body against damage from the environments. Slightly damaged skin will get healed based on the regenerative ability of human body, while any loss of full-thickness skin of more than 4 cm in diameter will not heal well without surgical intervention. Allografts and autografts have been employed for wound healing of large dermal defects; however, constraints on obtainable quantities, antigenicity and risk of disease transmission limit their use. Therefore, many studies are turning toward the skin tissue engineering approach to promote skin tissue regeneration. Skin tissue engineering is the emerging discipline of design and construction of spare parts for human skin to restore function based on principles of molecular developmental biology and morphogenesis governed by bioengineering.Dermal scaffold material is one of the three factors of skin tissue engineering. Following the guidance of the performance standards of dermal scaffold materials in skin tissue engineering, a novel collagen dermal scaffold material with native three-dimensional structure and ideal microstructure was prepared using a low-cost and simple preparation technology. The parameters of the preparation were optimized and the properties of the scaffold material were characterized.(1) The preparation technology was designed based on the traditional methods of ADM preparation and the mature pretreatments of leather technology using porcine skin as the raw material which was structurally and immunologically similar to human skin. The preparative scaffold material contained no porcine cells and bore ideal microstructure based on retaining native collagen three-dimensional structure. Pretreatments removed fine fair, sweat gland, subcutaneous tissue and so on. The combined treatments with enzyme, alkali, sodium dodecyl sulfonate and sodium chloride solution contributed to the final easy operation, low cost and ideal properties of the scaffold. After optimizations by adjusting concentrations and time and analyzing microstructure, mechanical properties, porosities, amino acid compositions and so on, the final technological parameters were chosen as follows,2.0 g·L-1 sodium hydroxide and 0.8 g·L-1 SDS solution for 15 h,3.0 g·L-1 trypsin-3.0 g·L-1 1398 enzyme-2.0 g-L-1 SDS solution for 6 h,4.0 g-L-1 SDS for 4 h, and 60 g·L-1 NaCl solution for 24 h.(2) The preparative scaffold material was analyzed containing HE staining observation, FTIR analysis, UV-VIS examination, amino acids analysis, SEM observation, porosity analysis, mechanical property measurement, biodegradation analysis in vitro, CLSM observation and so on to characterize its physical, chemical and biological properties, such as components, microstructure, tensile strength, biodegradation, cell growth and so on. The result indicated that no cells were observed, FTIR and UV spectra showed the typical collagen peaks, the content of collagen was 81.47%-87.34%, the scaffold material possessed porous structure with interconnected pore channels which diameter was about 100μm and porosity was about 89.00%, it could be completely degraded in vitro after 72 h in collagenase solution, mouse embryonic fibroblasts (3T3) cultured on the scaffold material proliferated well and distributed evenly.The preparation method is simple, low-cost. The preparative collagen dermal scaffold material combines advantages of both ADM and collagen sponge. It satisfies performance standards of dermal scaffold material in skin tissue engineering and is expected to have great possibilities for application in tissue engineering.