BACKGROUND:Titanium alloys lack biological activity when used as orthopedic implants,which can lead to implant loosening and periprosthetic infection.Therefore,it is of great significance to study a titanium alloy surface modification method that combines osteogenic and anti-infection functions.OBJECTIVE:To study the physical and chemical properties of titanium alloy modified with copper and strontium binary doped calcium silicate composite coating,and to evaluate its bone-promoting and antibacterial potential.METHODS:Ball milling and granulation methods were used to prepare composite powder containing copper oxide(CuO),strontium oxide(SrO),and calcium silicate(CS).A copper-strontium binary doped calcium silicate composite coating was prepared on the surface of titanium alloy(Ti6Al4V)through atmospheric plasma spraying technology.The composite coating was characterized.The titanium alloy extract,calcium silicate coating modified titanium alloy extract,copper-doped calcium silicate composite coating modified titanium alloy extract,and copper-strontium binary doped calcium silicate composite coating modified titanium alloy extract were co-cultured with MC3T3-E1 cells to detect the biosafety and osteogenic properties of the materials.Staphylococcus aureus(or Escherichia coli)were co-cultured with titanium alloy,calcium silicate coating modified titanium alloy,copper-doped calcium silicate composite coating modified titanium alloy,and copper-strontium binary doped calcium silicate composite coating modified titanium alloy.The in vitro antibacterial properties of the materials were detected by scanning electron microscopy and plate counting method.RESULTS AND CONCLUSION:(1)Scanning electron microscopy showed that a large number of nanostructures existed on the rough surface of the copper-strontium binary doped calcium silicate composite coating.The composite coating was successfully sprayed on the surface of titanium alloy.The composite coating could slowly release Sr2+and Cu2+in vitro.The release concentration of Sr2+was greater than that of Cu2+.(2)CCK-8 assay and cell live/dead staining results showed that the copper-doped calcium silicate composite coating modified titanium alloy had certain cytotoxicity.The calcium silicate coating and the copper-strontium binary doped calcium silicate composite coating modified titanium alloy had good biocompatibility.Alkaline phosphatase and alizarin red staining results showed that compared with titanium alloy and calcium silicate coating modified titanium alloy,copper strontium binary doped calcium silicate composite coating modified titanium alloy showed better osteogenic properties.(3)The results of scanning electron microscopy,bacterial coating,and bacterial counting method showed that compared with titanium alloy and calcium silicate coating modified titanium alloy,copper-doped calcium silicate composite coating and copper strontium binary doped calcium silicate composite coating modified titanium alloy can effectively inhibit the growth of Staphylococcus aureus and Escherichia coli,showing antibacterial potential.(4)The results indicate that copper strontium binary doped calcium silicate composite coating modified titanium sheet has good biocompatibility,osteogenic and antibacterial properties.

BACKGROUND:Titanium alloys lack biological activity when used as orthopedic implants,which can lead to implant loosening and periprosthetic infection.Therefore,it is of great significance to study a titanium alloy surface modification method that combines osteogenic and anti-infection functions.OBJECTIVE:To study the physical and chemical properties of titanium alloy modified with copper and strontium binary doped calcium silicate composite coating,and to evaluate its bone-promoting and antibacterial potential.METHODS:Ball milling and granulation methods were used to prepare composite powder containing copper oxide(CuO),strontium oxide(SrO),and calcium silicate(CS).A copper-strontium binary doped calcium silicate composite coating was prepared on the surface of titanium alloy(Ti6Al4V)through atmospheric plasma spraying technology.The composite coating was characterized.The titanium alloy extract,calcium silicate coating modified titanium alloy extract,copper-doped calcium silicate composite coating modified titanium alloy extract,and copper-strontium binary doped calcium silicate composite coating modified titanium alloy extract were co-cultured with MC3T3-E1 cells to detect the biosafety and osteogenic properties of the materials.Staphylococcus aureus(or Escherichia coli)were co-cultured with titanium alloy,calcium silicate coating modified titanium alloy,copper-doped calcium silicate composite coating modified titanium alloy,and copper-strontium binary doped calcium silicate composite coating modified titanium alloy.The in vitro antibacterial properties of the materials were detected by scanning electron microscopy and plate counting method.RESULTS AND CONCLUSION:(1)Scanning electron microscopy showed that a large number of nanostructures existed on the rough surface of the copper-strontium binary doped calcium silicate composite coating.The composite coating was successfully sprayed on the surface of titanium alloy.The composite coating could slowly release Sr2+and Cu2+in vitro.The release concentration of Sr2+was greater than that of Cu2+.(2)CCK-8 assay and cell live/dead staining results showed that the copper-doped calcium silicate composite coating modified titanium alloy had certain cytotoxicity.The calcium silicate coating and the copper-strontium binary doped calcium silicate composite coating modified titanium alloy had good biocompatibility.Alkaline phosphatase and alizarin red staining results showed that compared with titanium alloy and calcium silicate coating modified titanium alloy,copper strontium binary doped calcium silicate composite coating modified titanium alloy showed better osteogenic properties.(3)The results of scanning electron microscopy,bacterial coating,and bacterial counting method showed that compared with titanium alloy and calcium silicate coating modified titanium alloy,copper-doped calcium silicate composite coating and copper strontium binary doped calcium silicate composite coating modified titanium alloy can effectively inhibit the growth of Staphylococcus aureus and Escherichia coli,showing antibacterial potential.(4)The results indicate that copper strontium binary doped calcium silicate composite coating modified titanium sheet has good biocompatibility,osteogenic and antibacterial properties.