| In nature,specific microstructure and nanostructure of organism endows its specific surface properties.Excellent mechanical properties and biological properties of natural bone is closely related to its nano/micro multiscale structure.When biomaterials implanted into an organism,the interface between implant and bone tissue can be affected by its surface nano/micro structure.The surface topological structure of the implant biomaterials is considered to be one of the key factors of the biological characteristics.Nano/micro multiscale structures on the surface of biomaterials can directly(interaction between cell and biomaterials)and indirectly(interaction between proteins and biomaterials)alter the growth behavior of cells to a certain extent,such as cells adhesion,migration,proliferation,and differentiation.In order to regulate the interaction of materials and the organism,and optimize the biological performance of implant materials,the construction of the surface nano/micro scale bionic structure of the implant materials is very important.It is recognized as one of core research subjects in the field of tissue engineering and biomaterials.In the present thesis,based on the views of bionics,we developed a electrochemical deposition technique to construct nano/micro multiscale structured octacalcium phosphate(OCP)/silk fibroin(SF)composite coating and porous OCP coating.By research systematically the effect of silk fibroin molecules on electrochemical deposition process to achieve the controllable preparation of surface nano/micro structure,the effect of the surface nano/micro multiscale structure of OCP/SF composite coatings on the interaction of materials and the organism,and the the materials surface structure on protein adsorption behavior and cell growth behavior are discussed.We developed a construction technique of ordered sphere structure,and used as template to construct highly ordered porous structure silk fibroin scaffold successfully.The design and optimization of ordered template fabrication process was explored to achieve the controllable preparation of the pore size and structure of silk fibroin scaffold.The regulation effect of the pore size?interconnectivity and the ordered structure characteristics on cell adhesion?proliferation and migration was studied by in vitro cell culture experiment.The inner connection of the ordered porous structure and cell growth behavior is discussed.We developed a three-dimension(3D)bioprinting technique,specific three-dimensional structured silk-based scaffolds biomaterials were constructed successfully.It provides theoretical basis and technical support for the design and application of tissue engineering biomaterials.The main results of this thesis are outlined as following:(1)The OCP/SF composite coating with nano/micro multiscale structure were constructed successfully on the Ti substrate by using the electrochemical deposition technique.It indicates that the OCP crystal size decreased significantly from hundreds of nanometers to tens of nanometers and the microporous size decreased from tens of micrometers to several micrometers by adding silk fibroin component.The nano/micro multiscale structure is more mimetic to the natural bone.(2)The influence of silk fibroin concentration variation on nano/micro structure and biological performance of the OCP/SF composite coating was investigated systematically.It indicated that the average pore diameter and width of OCP crystalline ribbons of OCP/SF coatings kept decreasing significantly with the increase of SF concentration in electrolyte and levelled off when the SF concentration is higher than 1.0 mg/mL.(3)The hydrogen bubble template was proposed.The formation mechanism of nano/micro multi-level structure OCP/SF composite coating was explored.It demonstrated that the size of OCP crystal was limit in nano scale by adding silk fibroin.(4)The result of in vitro cell culture experiment indicate that,compared to the pure OCP coating and the mechanical mixture of CaP/SF,the OCP/SF composite coating can enhanced significantly cells(MC3T3-E1 and HUMSCs)adhesion,growth and proliferation.The nano/micro multiscale porous structure within the OCP/SF composite coatings may promote the cells adhesion,growth and proliferation,allowing more cells to grow in a congenial environment.The phenomenon is increasingly obvious with the SF concentration increasing,associated with the larger surface area of the composite coatings.(5)The result of protein adsorption test indicated that the amount of both BSA and Fn adsorption on pure OCP coating and OCP/SF composite coatings was significantly higher than that on bare Ti substrate.The amount of protein adsorption on the OCP/SF composite coatings increased with the higher SF concentrations.Compared to the pure OCP coating,the OCP/SF composite coatings can enhance selectively the specific Fn adsorption.(6)A highly ordered structured microsphere template was constructed successfully by using ordered microsphere template fabrication technique.The influence of some key experiment parameters on ordered porous structured silk fibroin scaffold was investigated systematically to achieve the controllable preparation of the highly ordered porous silk fibroin scaffolds.(7)The result of cell culture test indicated that the highly ordered porous silk fibroin scaffolds can control significantly the cell growth behavior,such as cell adhesion?proliferation and cell migration.It provides the research foundation and technical support for the model to study the effect of ordered structure on cell growth behavior.(8)We developed a 3D bioprinting technique.Using the riboflavin as the photoinitiator,the silk-based scaffold biomaterials with specific 3D structure were constructed successfully by using the photocurable 3D printer.It provides theoretical basis and technical support for the design and construction of high-performance biomedical scaffold materials with individualized nano/micro bionic structure. |
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