NIR-responsive TiO2 Biometasurface: Towards in situ Photodynamic Antibacterial Therapy for Biomedical Implants.

The implant-related microbial infection is a challenging clinical problem and its treatment requires efficient eradiation of the biofilm from the implant surface. NIR-responsive strategies have been proposed as an emerging efficient antibacterial therapy. However, the utilization of photosensitizer or photocatalytic/photothermal nanomaterials in the available approach likely induces high potential risks of interfacial deterioration and biosafety compromise. Herein, TiO2 /TiO2-X metasurface with potent NIR-responsive antibacterial activity was produced on Ti alloy implant by a newly invented topochemical conversion-based alkaline-acid bidirectional hydrothermal method (aaBH). Electromagnetic simulations proved that NIR absorption and near-field distribution of the metasurface can be tuned by the dimension and arrangement of the nanostructural unit. Promising antibacterial efficacy was proved by both in vitro and in vivo tests, with low power NIR irradiation for 10 mins. Besides, the designed nanostructure in the metasurface itself also showed excellence in enhancing the adhesion-related gene expression of human gingival fibroblasts that were exposed to 10 mins NIR irradiation, proving the potent nanostructure-induced biological effects. This work provides a biosafe and upscalable metasurfacing approach with extraordinary capacity of manipulating light adsorption, photocatalysis, and biological properties. This article is protected by copyright. All rights reserved.