Icariin-Functionalized Coating on TiO2 Nanotubes Surface to Improve Osteoblast Activity In Vitro and Osteogenesis Ability In Vivo

Surface modification of titanium is encouraged to facilitate early osseointegration in dental and orthopedic fields. Icariin is the main active constituents of Herba Epimedii, which has good bone-promoting ability. We established an icariin-functionalized coating composed of icariin and poly (lactic-co-glycolic acid) (PLGA) on TiO2 nanotubes surface (NT-ICA-PLGA) to promote osteoblast cell activity and early osseointegration. Surface topography, wettability and drug release pattern of the established NT-ICA-PLGA surface were characterized by scanning electron microscopy (SEM), contact angle test and drug release test. MC3T3-E1 osteoblast cell activity tests were performed using SEM, immunofluorescent staining, cell counting kit-8 and alkaline phosphatase assays. The osteogenic effects of different surfaces were observed using a rat model. Surface characterization proved the successful fabrication of the icariin-functionalized coating on the TiO2 nanotube structure, with increased wettability. The NT-ICA-PLGA substrate showed sustained release of icariin until two weeks. Osteoblast cells grown on the NT-ICA-PLGA substrate displayed improved cell adhesion, proliferation and differentiation ability than the control Ti surface. The in vivo experiment also revealed superior bone forming ability on the NT-ICA-PLGA surface, compared to the pure Ti control. These results imply that the developed NT-ICA-PLGA substrate has a promising future use as functionalized coating for implant surface modification.