Black phosphorus-incorporated titanium dioxide nanotube arrays for near-infrared–triggered drug delivery

Abstract

Inflammatory reaction after implantation is a serve complication of medical implants. Here, we propose a near-infrared (NIR) light stimulus-responsive drug-eluting platform based on titanium dioxide nanotube (TNT) arrays. Nano-sized black phosphorus (BP) prepared using a liquid exfoliation method served as a photothermal agent and were incorporated with TNTs, imparting TNTs NIR stimulus-responsive activity. The combination of BP and TNTs exhibited excellent photothermal conversion performance. Ibuprofen, a commonly used anti-inflammatory drug, was selected as the model drug and loaded on the NIR-responsive functional TNTs. A coating of 1-tetradecanol (TD) was used as a thermosensitive gatekeeper to prevent drug release at normal body temperature. Upon exposure to NIR light, the NIR-responsive drug delivery system transformed light energy to thermal energy that melted the TD layer and led to drug release from the reservoir. Furthermore, the combination of BP and TNTs showed enhanced biomineralization performance because of the degradation of BP into phosphate. Moreover, BP-modified TNTs showed no obvious cytotoxicity to MC3T3-E1 cells. Thus, this NIR light-responsive drug delivery system shows potential for controlled drug delivery in Ti-based orthopedic implants to overcome the challenges of tissue inflammation after implantation.