Bionic Calcium Carbonate Nanocomposite Controllable Fabrications And Biocompatibility Research

As the problems like severe trauma, tumor resection, bone infection, senile osteoporosis and congenital defects are increasingly serious, which cause the major health problems like bone damage and bone loss in real life, they greatly influence people’s survival ability and the quality of life; Owing to the demand surge of bone graft material for bone tissue repair, spinal fusion, artificial false body replacement surgery clinical, the autogeneous bone and allograft bone source become very scarce. However, traditional polymer and metal alloy bone graft substitute materials are difficult to degrade, which make them no longer satisfy human psychological and physiological requirements. Therefore, to prepare the synthetic materials with biological activity and biocompatibility is becoming a key issue. It has been recognized that the biomineralized materials with controllable morphology are more suitable for bone tissue repair and replacement in the combination of material science, biology and tissue engineering.Based on the above knowledge, the main contents of this thesis are as follows:1. Chi-CaCO3mineralization composite has been fabricated by a one-step co-electrodeposition method. In this experiment we fully explained the bionic theory, By changing the precursors concentration, deposition potential and time, various chitosan-based composites were prepared with controllable morphologies, including nanowires, nanosheets, nanoflowers, and irregular cluster aggregates. And because the nanostructured chitosan-calcium carbonate mineralization complex posses a good biocompatibility, biological activity, and diversity well, it will be a promising candidate for the preparation of biological mimic materials.2. The detailed studies were perfomed by using carbon-based materials, including functional ized carbon nanotubes (fCNTs), and graphene (G) as the mineralized nanostructure-directing agent. By a simple and facile electrodepositon approach, the nanostructured compound composed of chitosan-fCNTs were sysnthesized. By the modified hydrothermal synthesis approach, the composite of G-CaCO3was prepared. It was found that nanosized CaCO3particles were uniformally distributed onto the surface of graphene nanosheets. The cell culturing experiments display that the as-prepared carbon-based nanomaterial have good biological activity, and can promote cell attachment and growth, exhibiting excellent cytocompatibility.3. Nano fibrous network-like CaCO3-chi (CaCO3-Chi NFs) composite has been successfully fabricated in a simple and controllable approach based on one-step electrodeposition. Results confirm that chitosan can behave as a structure-directing agent during the formation of CaCO3-chi composite coating, playing an important role. The as-formed CaCO3-chi NFs were observed to be covered by multiple small nanoparticles (NPs) with an average diameter of～25nm. These uniform NPs were aligned along the surface of NFs, constructing a3D hierarchically interlaced network. Cytocompatibility of these NFs was evaluated by cells morphology and MTT assay by culturing MC3T3cells. The results show that the composite coating of CaCO3-chi NFs featuring with interconnected pores, loosing3D assemble, large surface area, and high mechanical strength, possess excellent cytocompatibility, greatly facilitating cell adhesion and proliferation. Our research demonstrates that the composite of CaCO3-chi NFs can be fabricated in an easy manner, i.e. electrolysis induced biomineralization, and act as a promising scaffold for tissue engineering applications.