ABSTRACT
Objective:To investigate the antibacterial and osteogenic properties of biomimetic mineralized iodine-loaded coating with micro-nano topography on the surface of bone implants.Methods:After the fiber network structure of sodium hydrogen titanate was constructed by alkali thermal reaction on the surface of Ti6Al4V (noted as AT), it was biomimetically mineralized in the modified simulated body fluid to form a micro-nano topology with high specific surface area (noted as AT-CaP), and finally loaded with PVPI to construct a novel antibacterial osseointegration coating (noted as AT-CaP-PVPI). The study was conducted in AT, AT-CaP, and AT-CaP-PVPI groups, in each of which 3 parallel experiments were performed. The morphology and colony counting of Staphylococcus aureus on the coating surface were observed to detect the in vitro antibacterial performance of the coating. Fifteen male SD rats were randomly divided into 3 groups ( n=5): AT, AT-CaP, and AT-CaP-PVPI. After intramedullary injection of Staphylococcus aureus into the lower end of the femur in the SD rats, titanium rods coated with AT, AT-CaP, and AT-CaP-PVPI were inserted into the marrow cavity. The osteogenesis, volume ratio of new bone mass and number of trabeculae on the surface of the femoral implants were compared between the 3 groups 4 weeks after operation. Results:In AT and AT-CaP groups, a large number of bacteria grew in their inherent elliptical or spherical shape on the implant surface and a large number of colonies were seen on the plate; in AT-CaP-PVPI group, the bacteria on the coating surface exhibited membrane deformation and depression, some of them were completely broken and dissolved, and a large number died. There was almost no new bone formation around the implants in AT group; new bone scattered around the implants with discontinuous distribution in AT-CaP group; a great amount of new bone was seen around the implants with even distribution but no signs of infection in AT-CaP-PVPI group. The volume ratio of new bone mass and the number of trabeculae on the implant surface in AT-CaP-PVPI group were 0.453±0.206 and 6.055±0.536, respectively, significantly higher than those in AT group (0.046±0.028 and 1.667±1.249) and AT-CaP group (0.188±0.052 and 3.804±0.889) ( P<0.05). Conclusion:Biomimetic mineralized iodine-loaded coating with micro-nano topography on the surface of bone implants shows good antibacterial and osteogenic properties.