Influence of Photocatalysis on antibacterial properties and Osseointegration of polymeric implant poly (ether–ether–ketone)

To investigate the influence of photocatalysis induced by nanoscale strontium titanate (SrTiO₃) and ultraviolet (UV) C photofunctionalization on the antibacterial properties and osseointegration of implant-grade polymer poly (ether ether ketone) (PEEK). Magnetron sputtering was utilized to prepare a nanoscale SrTiO₃ coating on the surface of PEEK specimens. Subsequently, the photocatalyst SrTiO₃ performed a photocatalytic reaction under the induction of UV–C photofunctionalization. The specimens were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X–ray spectroscopy (EDX), and X–ray diffraction (XRD). The antibacterial properties were investigated by plate colony counting, bacterial adhesion observation, and live/dead bacteria staining for Streptococcus gordonii. In vivo osseointegration was evaluated by Micro-CT and histology using the Wistar rat femur implant model. One–hundred nm thickness SrTiO₃ photocatalyst was constructed on PEEK after magnetron sputtering, the three–dimensional morphology of the specimens was changed, and strontium (Sr) and titanium (Ti) elements were introduced into the PEEK surface after photocatalyst coating. UV–C photofunctionalization did not change the three-dimensional morphology of specimens but increased their surface oxygen (O) content, especially photocatalyst coated PEEK. In addition, the crystal structure of each group did not change. Bacterial experiments showed that UV–C photofunctionalization improved the PEEK's antibacterial activity, and SrTiO₃ photocatalyst amplified the modification performance of UV–C light. In vivo experiments demonstrated that under the synergistic effect of SrTiO₃ photocatalyst and UV–C photofunctionalization, implants had the best osseointegration. This investigation indicated that photocatalysis induced by nano SrTiO₃ coating and UV–C photofunctionalization elevated PEEK's antibacterial activity in vitro and osseointegration in vivo.