Regulation The Morphology Of Mineralization Nano-Particles Based On Collagen Composite Template And The Biological Assessment

Hydroxyapatite,with good bio-compatibility and osteoinductivity,is the main inorganic constituent of nature bone and to be used bone repair material widely.The natural bone is not formed with the regulation of a single template molecules but a common regulation of a variety of template molecules.Many proteins and macromolecules inclued many biological molecules were used as template to mediate and regulate the growth of inorganic crystals in the process of mineralization.In this project,we studied on preparing collagen-based biomineralized nanoparticles with different shapes,by introduing a secondary template(namely chondroitin sulfate,sodium alginate,polyacrylic acid)to form a composite template by hydrogen bond interaction.The properties of surface morphology and crystalline were explored by the SEM and TEM.They all showed that Col-CS/HA particles that had parallel arrangement with large area along the long axis and present long rod and highest crystallinity,while Col-SA/HA particles had stacked lamellar structure and Col-PAA/HA particles present spherical and lowest crystallinity.Furthermore,the results of XRD,FTIR and TGA showed that the inorganic phase of nanoparticles were hydroxyapatite and the introduction of the second different molecular template had certain influence for mineralization system,which produced different morphology of nanoparticles.At present,there are a number of studies focused on the interaction of nanoparticles and cell to understand the transportation and internalization of particles into the cells,and its influence on the biochemical and molecular level.Cell proliferation experiments for evaluating the influence on the behaviors of BMSCs by different morphology nanomaterials confirmed that cell proliferation rate of Col-PAA/HA group was higher than the other two groups,and this group was more suitable for cell growth and proliferation.Besides,the spherical particles Col-PAA/HA more easily entered into the cell to be captured and absorbed by lysosome to affect cell growth,proliferation,differentiation through a series of experiments like the cell swallowed experiments,fluorescent tags,the co-localization of nanoparticle and lysosome,flow cytometry.Furthermore,different shapes nanoparticles could influence the osteogenesis of BMSCs and have the different ability of bone repairing.Many experients were found that the Col-PAA/HA particles could better promote the differentiation of BMSCs to osteogenesis direction than the other two groups,which included the protein produced in the process of osteogenesis differentiation.Finally,the biocompatibliy in vivo were estimated by hypodermic implantation,the capacity of bone repairing was investigated by skull repair experments.The results suggested that comparing with other groups,the Col-PAA/HA had best degradation and most powerful bone repair effect.In addition,each kind of materials exhibited great biocpmatibiliy,nice degradation capability and good ability of bone repairing,which could be induced into blood vessels to promote bone matrix secretion and mineralization.