| At present,interventional therapy is still an effective means of treatment of cardiovascular disease,which requires implanted medical materials have a good function to promote endothelial recovery.As a material surface modification technology,Surface patterning can effectively improve the performance of implanted materials.In addition,it was found that mesenchymal stem cells(MSCs)could be induced to differentiate into vascular cells(endothelial cells/smooth muscle cells)by constructing microsatellite topologies or extracellular matrix topologies in the early explorations of this study group,Which provides a new approach for the study of cardiovascular implant materials and the bionic construction of vascular endothelialization.In this study,a large/small diameter titanium dioxide nanotube topology(Nano-TOPO)sample prepared by UV lithography,anodic oxidation and acid etching is used as the experimental group,meanwhile,the large diameter titanium dioxide nanotube topology(B-Nano-TOPO)sample prepared by combining UV lithography and two anodic oxidation、the samples(TiO2-Groove)prepared by acid etching,the samples(TiO2-Nano-S/TiO2-Nano-B)prepared by anodic oxidation of the acidic/neutral electrolyte system and the untreated flat titanium dioxide(TiO2-Flat)samples are used as control group.-Firstly,The morphologies of the samples are imaged by SEM.The surface chemical composition is examined by FTIR.The crystal structure of the TiO2 is detected by XRD,in particular,the mechanical properties of TiO2 nanotube films with different tube lengths are studied.Secondly,Endothelial cell and smooth muscle cell compatibility are evaluated.Finally,the effects of short-term growth behavior and long-term induction on mesenchymal stem cells are studied.The material characterization shows that the trench width of the micrometer-sized trench in the sample is about 20μm,the ridge width is about 10μm;the diameter of TiO2 nanotubes relative to small diameter is about 30nm,and the large diameter is about 100nm;the crystalline structure of the sample is anatase phase,which ensures that the prepared samples meet the experimental requirements.The study of mechanical properties show that the shear stress of the nanotubes can not destroy the structure of TiO2 nanotubes for 28 days,while the tensile experiments show that the TiO2 nanotube films have good tensile properties under 10%strain conditions,The film did not damage.The mechanical properties of TiO2 nanotube films show that,the fluid shear force simulated the blood flow in vivo can not damage the structure of TiO2 nanotubes in 28 days,and the tensile test showe that the TiO2 nanotube films had good tensile properties under the 10%strain condition..The results of endothelial cells and smooth muscle cells compatibility evaluation show that the effect of TiO2 nanotubes prepared by acidic/neutral system on endothelial cells’behavior was not significantly different.TiO2 nanotubes and their topoisomer have inhibitory effect on endothelial/smooth muscle cells,But the inhibition of endothelial cells is weak,and the inhibition of smooth muscle cells is strong;Nano-TOPO and B-Nano-TOPO samples have weak guiding effect on the orientation of endothelial cells,and could significantly promote the growth orientation of smooth muscle cells.The results of mesenchymal stem cells show that TiO2 nanotubes could inhibit the proliferation of MSCs,the presence of micro-nano topological structure could not weaken the inhibitory effect of TiO2 nanotubes on MSCs.Nano-TOPO samples have better effect on elongation and orientation of MSCs,which is significant and more time-bound.The long-term induction experiments show that the surface cells of B-Nano-TOPO and Nano-TOPO samples have a-SMA positive expression,indicating that these two micro-nano topologies could induce MSCs to differentiate into smooth muscle,while Nano-TOPO samples could induced differentiation of MSCs in advance. |
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