Preparation And Biological Assessment Of Strontium-substituted Nanohydroxyapatite Coating On Sandblasted-dual Acid Etched Titanium Surface

The main purpose of surface modification of dental implant is to shorten the time of osseointegration, and as to reach immediate or early loading. This study focused on the fabrication of strontium-substituted nanohydroxyapatite coating on sandblasted-dual acid etched titanium surface using electrochemical deposition technique and the detailed biological assessment of this coating.The electrochemical deposition technique was used to fabricate of strontium-substituted nanohydroxyapatite coating and nanohydroxyapatite coating on the prepared titanium surface. The surface topography of titanium disks were determined by Field Scanning Electron Microscopy.Mouse MC3t3-E1preosteblasts and bone marrow stromal cells obtained from newborn male SD rat were cultured on electrochemically deposited strontium-substituted hydroxyapatite(EDSHA) coating, electrochemically deposited pure hydroxyapatite(EDHA) coating and roughened titanium surface respectively after measuring the purity by flow cytometer, so as to observe the changes of cell cytoskeleton and morphology and calculate the cell shape factor for evaluating the effect on cell spreading. Moreover, cell proliferation, alkaline phosphatase(ALP) activity, osteocalcin secretion and extracellular matrix calaium mineralization were measured at various periods. BMSCs and MC3t3-E1preosteblasts cultured on EDSHA coating showed increased ALP activity, osteocalcin secretion, and extracellular matrix calaium mineralization compared with the other two groups. And cells cultured on EDHA coating also showed increased biological activity compared with the roughened group.Obviously, from this study we can get a conclusion that strontium-substituted nanohydroxyapatite coated surface by electrochemical deposition can promote the attachment, proliferation, osteogenic differentiation of BMSCs and MC3t3-E1preosteblasts on titanium surfaces in vitro and has the potential to improve implant integration at the early stage of bone healing compared to pure HA coated surface.