Objective To review the application of genipin for the modification of natural biomaterials as a crosslinking agent and progress in research. Methods Domestic and foreign literature on application of genipin for the modification of natural biomaterials as a crosslinking agent was thoroughly reviewed. Results Genipin is an effective natural crosslinking agent with a very low level of cytotoxicity compared with conventional synthetic crosslinking agents. Tissues fixed with genipin can maintain a high level of stability as well as resistance to enzymatic degradation. Conclusion Genipin is a promising substitute for conventional synthetic crosslinking agents, which has offered an alternative for modification of natural biomaterials for tissue engineering.
ObjectiveTo explore a simple and rapid pathological slices method to observe the porous structure and the composition distribution of composite materials. MethodsTaking polyurethane/small intestinal submucosa (PU/SIS) composite as an example, PU/SIS was OCT-embedded and sliced into sections by frozen section technology, after which general observation of the section integrity was carried out. After dyed with water-soluble eosin in alcoholic solution, the staining effect and the porous structure of the composite were observed under light field microscope. Sections were sealed with five different sealing methods. Group A: sealing piece using glycerogelatin method; group B: anhydrous alcohol dehydration→transparency using TO transparent reagent→sealing piece using neutral quick drying glue; group C: color separation using deionized water→air-drying→sealing piece using neutral quick drying glue; group D: air-drying→transparency using TO transparent reagent→sealing piece using neutral quick drying glue; group E: air-drying→sealing piece using neutral quick drying glue. Then, the morphology and the components distribution of the composite were observed under light field microscope, and the simple and feasible method was selected as optimum method. ResultsFrom general observation, the frozen section of the PU/SIS composite, which was 6 μm in thickness, was complete and continuous. Although the outline of the material and the porous structure in the sections could be observed clearly under light field microscope, the two components still could not be identified by using eosin staining method. After sealing piece, the material components in groups A, B, and C still could not be identified or be dissolved and deformed; the morphology of the material in groups D and E were preserved and the two components in the composite were clearly visible. ConclusionThe morphology and the components distribution of PU/SIS frozen sections can be characterized after soluble eosin staining and neutral quick drying glue sealing.