Construction Of Electricity Microenvironment Based Onelectroactive Polymer Membrane And Study Of Its Interaction With Cells

In view of the problem that bone-formation is slow in bone repair and bone incompatibility with tissue is poor for titanium implantation,there are a lot of researches focused on the biological activity of titanium to promote its combination with bone.However,a few studies are about electrical physiological microenvironment for promoting bone tissue growth.Electrical microenvironment is one of the important microenvironment of bone tissue.Electric signal stimulation is beneficial to bone formation and is closely related to the growth and reconstruction of bone tissue.Bone tissue has piezoelectric properties and can respond to mechanical stress to generate electrical signals,forming electrical microenvironment,thus regulating the bone regeneration and reconstruction.Clinical studies have shown that electrical signal stimulation is conducive to the promotion of bone defect regeneration.Therefore,the microenvironment of bone tissue is simulated,and the electrical microenvironment is constructed on the surface of titanium implant to improve the effect of bone consolidation and promote bone regeneration.It provides new ideas and ways for preparing new implant materials.It has important scientific research value and clinical significance.In this study,the following works were done on the construction of polymer microenvironment:(1)The electrical microenvironment based on the conductive polymer film was constructed on the surface of medical titanium by electrochemical polymerization method,and the biomacromolecule dopant chondroitin sulfate was introduced.The polypyrrole film nanostructures were controlled by changing the dopant concentration.The mechanism of chitosan sulfate as a dopant and structural promoter in the construction of polypyrrole nanostructures was discussed.The biological properties of the nanostructured polypyrrole film were investigated by a series of in vitro experiments.It is proved that the electrical microenvironment has good biocompatibility and is favorable for cell proliferation and osteogenic differentiation.This study provides the basic research for constructing the electrical microenvironment based on conductive polymer film and provides new ideas and ways for constructing new bone implant material.(2)Based on the change of a series of physicochemical properties along with redox reaction of conductive polymer,the electrical microenvironment of conductive polypyrrole films in different state was constructed by using the weak redox potential.The presence or absence of dopant ions is controlled by the opening/closing effect,surface wettability and surface charge distribution of the polypyrrole nanocones array,thus realizing the regulation of bacterial adhesion,protein adsorption and cell adhesion spread to the polypyrrole film electrical microenvironment.The experimental results show that the electrical environment of the conductive polypyrrole film has good biocompatibility and has the important theoretical and practical value to regulate the antibacterial,protein and cell behavior.(3)This study is based on the piezoelectric effect of bone tissue,and further the problem of the need for external power supply for the electrical environment based on the conductive polymer film.The piezoelectric polymer film is used to generate the electrical signal in response to the mechanical stress to form the electrical microenvironment for promoting cell osteogenesis differentiation and bone formation.First,the polyvinylidene fluoride film was prepared by solution casting method,and the polarization of the PVDF was studied.The experimental study shows that the polarized piezoelectric PVDF membrane is enriched with negative charge,which is favorable for the deposition of cell matrix minerals,promoting cell proliferation,osteogenic differentiation and osteogenic gene expression.In this study,the design of electrical microenvironment based on piezoelectric polymer film realized the imitation bone piezoelectric effect and the design concept of bone implant material with electrophysiological microenvironment.(4)In order to solve the problem of electrical signal generation for conductive polymer film and electrical signal transmission in the electrical micro-environment based on the piezoelectric polymer,simulating the piezoelectric effect of the bone and the electrical environment of the bone tissue are further proposed.Combine with conductive polymer and piezoelectric polymer,the research idea of constructing electrical microenvironment based on conductive piezoelectric composite polymer film.Firstly,the polyvinylidene fluoride film was prepared by solution casting method,and then the polypyrrole film was electrochemically constructed on the surface of the polyvinylidene fluoride film to obtain the electrical microenvironment based on the conductive piezoelectric composite polymer film.The microenvironment of the composite polymer film is more favorable for cell adhesion,bone minerals deposition and cell osteogenesis than the single polymer microenvironment.Cell culture experiments under the dynamic stress load show that the microenvironment responds to mechanical stress for enhanceing cell adhesion spread.The idea of constructing the electrical microenvironment based on conductive piezoelectric composite polymer membrane proposed in this study will provide new ideas and methods for improving the osseointegration and design of the bone implant using physiological exercise to promote bone repair.