Controlled drug release and antibacterial enhancement via NIR-activated CuS-modified TiO2 nanotubes arrays

Two primary obstacles impede the longevity of implants: bacterial infection and fixation loosening. This research introduces an innovative near-infrared (NIR) light-activated drug delivery system tailored to enhance the antimicrobial efficacy and bone integration of titanium-based implants. Titanium dioxide nanotube arrays (TNTs) were modified with epoxy for covalent bonding of therapeutic agents, and copper sulfide nanoparticles (CuS NPs) were added for regulated drug release. Alendronate sodium (ALN), an osteoporosis medication, was successfully bonded to the nanotubes. In vitro experiments showed that the release rate of ALN from TNTs-ALN reached 94 % within 36 h. In contrast, minimal release was observed in TNTs-ECH-ALN-CuS, which effectively addresses the prevalent issue of abrupt drug discharge typical in conventional delivery systems. In the context of NIR light exposure, the TNTs-ECH-ALN-CuS exhibited a notable ALN release efficacy of 48 %, demonstrating effective control over drug delivery. Additionally, the generation of ROS, coupled with temperature elevation under NIR exposure, endowed the modified TNTs with exceptional antibacterial efficacy, exceeding 99 % inhibition against E.coli and S.aureus . We observed a pronounced enhancement in the drug delivery mechanism, characterized by a reduction in the initial burst release and a sustained, controlled release, coupled with robust antibacterial action and notable biological performance.