Fabrication And Biological Evaluation Of The Co-doped Strontium And Zinc Nanorods Coating On Porous Pure Titanium Surface By Hydrothermal Synthesis

For dental implants,early infection and peri-implantitis after implant restoration are major reasons for implant failure.Plaque biofilm formation is the initiator for implant-related infection.Therefore,it's urgent to develop a new antibacterial implant materials or treatment methods.It is found that nanostructured titanium surface can resist bacterial adherence and promote bactericidal capability.Zinc(Zn)not only exhibits excellent antibacterial behavior with broad spectrum and limits drug-resistance bacteria induction,but also is active in osteogenesis.Strontium(Sr)has various effects of improving immunologic reaction,promoting osteogenesis and inhibiting osteoclastic differentiation.In this study,Zn-and Sr-incorporated micro/nano-structured titanium surface with nanorods was fabricated by a two-step hydrothermal process,aiming to improve osseointegration and reduce implant failure caused by implant-related infection and broaden new ideas for the future research on the antibacterial properties of biological materials.Materials & Methods1.The Mod Ti surfaces were used as a control.The characterization of different surfaces was detected by a field emission scanning electron microscope,X-ray diffractometer,X-ray photoelectron spectroscopy and electrochemical analysis.2.S.aureus and P.gingivalis were selected to evaluate antibacterial properties through Live/Dead Staining and watching the adhesive bacterial morphology under a field emission scanning electron microscope.3.The rat bone mesenchymal stem cells(r BMSCs)were cultured on different surfaces to detect their initial adhesion,proliferation,alkaline phosphatase activity and the expressions of osteogenesis related genes in vitro.Results1.In characterization,the results revealed that nanorod-like particles with a diameter of 30-50 nm were evenly distributed on this novel surface and was composed of well-crystallized Sr Ti O3 and Zn Ti O3 phases.The release of Zn2+ and Sr2+ was a controlled and long-term process for up to 21 days.With sufficient interface bonding strength(42.00 ± 3.00 MPa),SLA-Zn/Sr enhanced the corrosion resistance of titanium.2.In antibacterial test,Zn-containing nanorod-like particles and the morphology could work together,decreasing adhesion of S.aureus and P.gingivalis,compared with the controlled group.More importantly,we found that this novel surface could reduce the biofilm formation of S.aureus by inhibiting the secretion of polysaccharide intercellular adhesin.3.Osteogenesis experiments in vitro revealed that,this novel surface performed a good cytocompatibiliy with r BMSCs and enhanced the cellular initial adhesion,proliferation and the expressions of alkaline phosphatase and osteogenesis related genes.Conclusions This research provides a new surface modification method on titanium substrate for multi-functional implant material development.Due to the co-doping of Sr and Zn in the coating,biomechanical stability,antibacterial capability and early osteogenic inductive effect are enhanced,which has the potential to be applied in dental implantation in the future.