| The study is to develop a new technology to construct a collagen/chitosan scaffold for dermal regeneration, which has the similar microstructure to extracellular matrix of dermis, suitable degradation degree and good biocompatibility. Further, the sterilization method and the package design of the product were considered. Finally, a model was constructed to study the influence of the compressive force on the cells’ behaviors in scaffold.In this study, a facile method to prepare the glutaraldehyde (GA) cross-linked collagen/chitosan porous scaffold(S2) was reported. The properties of S2were compared with the scaffolds prepared by the previous method (S1-0.25%).Firstly, the macroscopic shapes and microstructures of the collagen/chitosan scaffolds fabricated by different methods were illustrated.Compared to the rough surface and collapsed inner structure of S1-0.25%,S2showed a smooth surface and controlled size. The swelling ratios of the scaffolds were investigated by the phosphate buffered saline (PBS)-immersion test. It was found that, when treated by GA with same concentration, S1-0.25%and S2showed the similar swelling ratios.Moreover, the swelling ratios of all the scaffolds are big enough to ensure the nutrients supply in the early stage of wound healing. The effects of the fabrication methods as well as the GA concentration on the cross-linking degree and in vitro degradation degree of the scaffolds were studied. When the concentration of the treating GA is same, the cross-linking degree of S2-0.25%is much higher than that of S1-0.25%,resulting in a lower degradation degree. Investigation of the tensile and compression properties of the scaffolds found that the mechanical property of S2-0.04%is closest to that of S1-0.25%.High Performance Liquid Chromatography (HPLC)was applied to determine the residual GA of the scaffolds fabricated by different methods.The results proved that, compared to water washing in S1-0.25%fabrication, oven drying is a feasible and effective method to remove the residual GA of S2.Finally, the cytocompatibility of S2was evaluated by in vitro culture of fibroblasts.The results of cell morphology and cell viability proved that S2-0.04%could retain the original good cytocompatibility compared with S1-0.25%and can accelerate cell infiltration and proliferation effectively. All these results indicate the facile method is a feasible method for the preparation of the GA cross-linked collagen/chitosan scaffold.To accelerate the industrialization of the collagen/chitosan dermal regenerating materials, issues about the production design such as sterilization method and package design were studied. The sterilization method was taken by EO (ethylene oxide) and y-ray with lOKGy,15KGy and25KGy dose. The result showed that EO sterilization destroyed the microstructure of scaffold. There still were bacteria in the scaffold, which was sterilized by γ-ray with10KGy and15KGy. The product sterilized by γ-ray with25KGy can achieve the medical sterilization standard only. The package of the collagen/chitosan dermal regenerating materials was consisted of the inner part and the outer part. The outer package was made of paper, on which the information of product property, instructions and the other relevance introduction were printed.The inner package contained PVC groove and adhesive paper, which can isolate the outside impurity effectively and avoid bacteria invading. It was improved that the sterilized scaffold in the package kept sterility state at60℃for one month.Finally, the influence of the compressive force on the morphology and viability of the cells in the scaffold was investigated.The SEM and CLSM images of the cell-seeded scaffold indicated that no obvious influence under the stress was found on the cell morphology. However, the stress can affect the viability of the cells in the scaffold.With the increase of the stress,the cell viability reached to a platform earlier. |
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