Near-Infrared Triggered Black Phosphorus/Zinc Oxide Nanocoatings Are Used to Resist Bacterial Infections in Additively Manufactured NiTi Alloy Implants

Additive manufacturing of NiTi alloys has emerged as a promising option for bone implants. However, the bioinertness and poor corrosion resistance of the alloy limit its clinical applications. More critically, the absence of antibacterial properties increases the risk of postoperative biofilm infections. To address this pressing issue, we have developed a bacteriostatic phototherapy protocol in which black phosphorus (BP) and zinc oxide (ZnO) nanoparticles are deposited on the surface of a polydopamine (PDA)-based additive manufacturing NiTi alloy. Under near-infrared (NIR) light irradiation, the synergistic photothermal action of PDA and BP exhibits remarkable phototherapeutic capabilities. Concurrently, the photothermal effect enhances the release capacity of Zn²⁺, establishing a synergistic strategy for biofilm elimination with an antibacterial rate of up to 93.8%. Furthermore, the coating demonstrates excellent interface adhesion, which improves the biocompatibility of the alloy. The synergistic antimicrobial regimen induced by NIR is conducive to the clinical application of NiTi alloy implants.