Development and evaluation of osteogenesis and antibacterial properties of strontium/silver-functionalized hierarchical micro/nano-titanium implants

Abstract

Promoting implant osseointegration while preventing infection is one of the major challenges in the development of dental implants. In this study, nano-needle-like structures were prepared on titanium by hot alkali treatment and then coated with uniform silver (Ag) and strontium titanate (SrTiO3) through magnetron sputtering. The results of ion release showed that the SrTiO3 outer coating reduced the release of Ag ions by 30% and 15% respectively on the 4th and 7th days, thus effectively improving the bioactivity of the Ag-modified substrates. In vitro experiments demonstrated that the Ag/SrTiO3-coated specimens (AH-Ti/Ag/Sr) had an excellent effect on the osteogenic differentiation of MC3T3-E1 cells and exhibited antibacterial function against Staphylococcus aureus and Escherichia coli (percentage of dead/total bacteria: ∼93% and ∼88%). Moreover, the in vivo results further confirmed that the Ag/SrTiO3 bilayer coating significantly promoted osteogenesis around the AH-Ti/Ag/Sr implant (the new bone volume and the number of trabeculae: 1.5 and 1.4 fold of the control group) and enhanced the bonding strength between implant and surrounding bone (about 1.9 fold of the control group). All these findings indicate that AH-Ti/Ag/Sr can substantially improve osteogenesis in complex oral microenvironment, and thus has potential applications in oral implantology.