Combined application of silica particles and zirconium hydrogen phosphate coating to improve the friction resistance and osteogenic/anti-inflammatory properties of micro-arc oxidation-treated titanium

Titanium (Ti) oral implants, as foreign bodies, can easily trigger an inflammatory response, and the metal ions/nanoparticles released by friction/corrosion in the body can also damage soft and hard tissues, leading to implant failure. To make up for deficiencies, a multifunctional composite coating composed of silica (SiO2) particles and zirconium hydrogen phosphate (ZrP) on the surface of Ti was prepared by combining micro-arc oxidation (MAO) and sol-gel technology. The characterization results of the surface physicochemical properties confirmed that a series of SiO2/ZrP-modified MAO coatings were successfully constructed. Compared with the control group, the doping of SiO2 particles effectively improved the friction resistance of the surface MAO coating, but worsened its corrosion resistance. After the surface was further covered with ZrP coating, the corrosion resistance defect caused by SiO2 particles was eliminated. With the increase of the ZrP thickness, the friction resistance of the target sample increased gradually. In addition, the specimens coated by ZrP coatings also presented better anti-inflammatory and osteogenic capabilities than the samples subjected to pure/SiO2-doped MAO treatment. Based on these advantageous properties, this novel composite coating may project good application prospects in promoting early osseointegration.