The Effect Of Copper-doped Nanotubes On Diffenent Stem Cells And Its Regulaton On Vascular Mature Cells

Surface modification of biomaterials can provide diversified functions for different clinical environments.Conventional surface modification methods(such as micro-nano patterning,functional group/molecule grafting,protein/peptide immobilization,etc.)usually respond to one or several specific functional requirements,and it is difficult to adjust in the complex body environment.Mesenchymal stem cells can be used for tissue damage repair,targeted therapy and so on.For one aspect,it can realize tissue engineering reconstruction through self-differentiation,for another aspect,it also can regulate other cells to realize tissue damage repair by secreting related factors.In vivo repair,behavior of stem cells depends on the regulation of the surrounding microenvironment.Thus,stem cells can be regulated by readjusting the physical and chemical factors of their surrounding microenvironment,which can promote the realization of the specific differentiation and secretion functions.The copper-doped titanium dioxide nanotube,as a promising surface modification method for cardiovascular biomaterials,can be endowed with the antibacterial function and the catalytic release capability of nitric oxide by loading copper.However,its application limitation has still existed in in vivo endothelialization of cardiovascular implants with larger surfaces.In this study,the techniques of stem cell regulation and surface modification have been used for designing and constructing a copper-doped titanium dioxide nanotubes surface equipped with mesenchymal stem cells to realize differentiation/secretion regulation and catalytically releasing nitric oxide,which will provide a new way for surface modification of cardiovascular biomaterials.In this paper,a series of titanium dioxide nanotube surfaces doped with copper of different concentration have been designed and constructed,the effect of these surfaces on different sources mesenchymal stem cells carried on them and the influence of the above complex surface of copper-doped titanium dioxide nanotubes equipped with mesenchymal stem cells on vascular environment mature cells,such as macrophage,endothelial cells,have been also researched.The main contents include:1.In this paper,we have designed and prepared copper-doped Ti O₂ nanotube surface with different copper concentration.The surfaces of copper-doped Ti O₂ nanotubes have been proved to be successfully prepared by the results of characterizations analysis of water contact angle,scanning electron microscope and X-ray energy spectrum.The copper content per unit area of the copper-doped Ti O₂ nanotubes has been calculated in the range of10-100?g/cm².The release of copper ions determined by atomic absorption spectrophotometer has been proved within a safe range.The catalytic release of nitric oxide determined by Griess reagent method has been also proved within the physiological concentration range.(Chapter 2).2.Because the copper-doped Ti O₂nanotubes can release copper ions to the solution in the process of catalytic release of nitric oxide,the effects of copper ions(free copper)of different concentrations,copper doped titanium dioxide nanotubes(copper compounds)with different copper concentrations and catalytic release of nitric oxide on the adhesion and proliferation of mesenchymal stem cells from different sources(adipose derived mesenchymal stem cells,bone marrow mesenchymal stem cells)have been discussed.The results have showed that the two kinds of mesenchymal stem cells exhibited better proliferation behavior in the solution with physiological concentration of copper ions and on the surface of the sample(TNTCu3)containing 25.57?g/cm² of copper per unit area in presence of catalytic release of nitric oxide.(Chapter 3 and Chapter 4)3.The influences of the above complex surface of copper-doped titanium dioxide nanotubes equipped with mesenchymal stem cells on vascular environment mature cells(macrophages,endothelial cells)have been also tentatively explored by means of non-contact co-culture in transwell.It has been proved that the complex structure mentioned above can regulate the perivascular mature cells by readjusting the secretion of stem cells,and have shown the potential capability of anti-inflammatory,anti-coagulation and promoting endothelialization by the determination of inflammatory factors(TNF-?and IL-10)and endothelial function factors(PGI2,E-selectin,TM and TFPI).(Chapter 5)In this paper,a composite surface of copper-doped titanium dioxide nanotube equipped with mesenchymal stem cells has been designed and constructed,the appropriate copper content has also been screened out.It has been proved that this composite structure can regulate the vascular environment mature cells by readjusting the secretion of stem cells.Thus,a new effective strategy for surface modification of cardiovascular materials has been proposed.