Dose-response Relationships Of Copper Ions And Its Regulations On The Surface Properties Of Medical Titanium

Copper?Cu?is an essential trace element in human bodies.It is widely used to modify biomaterials due to its multiple biological functions including good antibacterial ability,osteogenic and angiogenic activities.However,high copper content could inhibit the effective biofunctions of cells or induce cytotoxicity due to its multifunctions.In this work,the behaviors of cells and bacteria responding to Cu²⁺solution were explored.Cu modified layers were produced on titanium surface by plasma immersion ion implantation?PIII?technology and then were further processed by heating treatment?HT?.Then,the physicochemical properties and biological behaviors of modified layers were studied.The main research results were as follows:1.Three kinds of cells,human umbilical vein endothelial cells?HUVECs?,mouse osteoblastic cells?MC3T3-E1?,and rat bone marrow mesenchymal stem cells?rBMSCs?,were chosen to evaluate cellular behaviors.S.aureus and E.coli were chosen to evaluate antibacterial ability.Results showed that the HUVECs exhibited significantly higher tolerance to copper ions than MC3T3-E1 and rBMSCs,and rBMSCs was most sensitive to copper ions.Cu²⁺could significantly promote HUVECs migration in low concentration,but the advantage of Cu²⁺for HUVECs migration was slowed down in high concentrations.Moreover,Cu²⁺was beneficial to early osteogenic differentiation and relative genes expression of rBMSCs.There was a threshold concentration for Cu²⁺solution to exhibit effective inhibition against to both S.aureus and E.coli.When the concentration of Cu²⁺exceeded the threshold value,antibacterial activity could increase dramatically.2.Cu was introduced into the titanium surface by PIII technology.The anticorrosion ability of the modified layer was enhanced and the Cu²⁺had a steady release ratio from the modified layer.The results showed that the sample with low Cu content at the surface promotes the proliferation of rBMSCs and HUVECs but can not inhibit the growth of E.coli and S.aureus.The antibacterial ability of the samples with higher Cu content at surface was significantly enhanced,and no obvious cytotoxicity was observed.Therefore,it is possible to acquire a balance between antibacterial ability and biocompatibility of Ti by controlling the contents of Cu in the modified layer.3.Cu-doped titanium dioxide(TiO₂)was acquired from Cu-PIII modified layer postprocessing with heating treatment.The results showed that rutile phase TiO₂ was formed on the surface of titanium.The increase of heat treatment temperature and Cu content were beneficial to the growth of TiO₂ grains.Cu-2h-HT800 performed good antibacterial ability to E.coli in visible light in vitro.