F-Doped Micropore/Nanorod Hierarchically Patterned Coatings for Improving Antibacterial and Osteogenic Activities of Bone Implants in Bacteria-Infected Cases.

Advanced titanium (Ti) based bone implants with antibacterial and osteogenic activities are extremely needed in clinics. Herein, biomimetic hierarchical micropore/nanorod patterned coatings (MNRs) on Ti were developed, in which the nanorods revealed a fixed interrod spacing of about 70 nm and consisted of fluorine (F) incorporated CaSr(PO)(OH) (Sr-HA, strontium containing hydroxyapatite) with the fixed Sr but different F content. The incorporation of F was determined by XRD, FTTR, and TEM, revealing the substitution of OH in Sr-HA to F. The topography, surface roughness, and hydrophilic nature of MNRs were not apparently affected by the incorporation of F. The antibacterial and osteogenic activities of MNRs were assessed and in a bacterial-infected rabbit model. Both the and results showed that F-free and ∼1 wt % F doped MNR significantly promoted osteogenic activity compared to that of Ti but showed a lack of antibacterial activity. The incorporation of a higher dose of F led to the significantly improved antibacterial and osteogenic activities, and the effects were related to the incorporated F dose. In total, compared to F-free, ∼1, ∼2, and ∼7 wt % F doped MNRs, ∼5 wt % F doped MNR significantly enhanced antibacterial and osteogenic activities, especially new bone formation and osseointegration in the bacteria-infected case, showing a high potential as the next generation of advanced bone implant.