Research On Fabrication Of Bionic Composite Materials With Hierarchical Structure By Using Ice-Templating

Natural organisms' hard tissue such as bones and shells have hierarchical structure from the micro to the macro scale. How to simulate the hierarchical structure on bionic manufacturing, is the major challenge of the designing of tissue engineering scaffolds.In order to obtain a new multi-level layered composites and produce biomimetic materials not only have biological composition but also have a bionic structure, our study will be the combination of microsphere synthesis technology and Ice-Templating (IT) technology. Our experiments fabricated the biomaterials by unidirectional freezing the slurry of collagen, chitosan and nano-HA, nano-HA /PLA microsphere compound, and have created natural nacre-like lamellar structure with well mechanical response. To determine the appropriate combination of the research process, we study the characteristics of each cooling baths,salt-ice mixtures,the composite ratio of different ice slurry, etc. We also do the researches about the component, crystallinity, two-phase composite bonding, hydrogen bonding and material changes in the structure at all levels, morphology and other aspects of research, by using FTIR, XPS, SEM and other testing methods. At last but not least, the MSCs were co-cultured with the extracts of the multi-level layered composites to test the composite's cytotoxicity preliminary.The results show that: Multi-layered material can be produced by Ice-Templating method combined with microsphere technology; and layer thickness is controllable, different materials led to the different lamellar thickness; With different amount of the solvent the layer spacing varies; SEM observations confirmed the internal pore structure has good connectivity, a bridge similar to mineral bridge formed between Layers enhanced fracture toughness of the material; proportion method measured that the porosity is about 90% ; co-cultured the MSCs with material extracts, the results of MTT indicating the material has good biocompatibility. It is a potential new method for preparation engineering materials of ideal structure, good biocompatibility and with both the economy and environmental friendliness.