Plasmon-enhanced photothermal properties of Au@TiCT nanosheets for antibacterial applications.

Antibiotic-resistant bacterial strains have become an ever-increasing public concern due to their significant threats to health safety. Nanomaterial-based photothermal treatment has shown potential in antibacterial applications, but many nanomaterials exhibited limited photothermal activity that may compromise their antibacterial efficacies. Herein, we report a novel strategy based on efficient photothermal ablation and physical contact over a supported nanostructure by loading Au nanoparticles (NPs) on few-layered TiCT nanosheets (NSs) for antibacterial treatment. TiCT NSs are delaminated etching and sonication, and act as a reductant for the reduction of HAuCl·HO, producing "naked" Au NPs without any stabilizers. Meanwhile, by adjusting the Au/Ti ratio, the size and loading of the Au NPs are finely regulated, thereby providing an ideal model of a surface-clean Au@TiCT heterostructure for probing the composition-performance relationship. Upon irradiation with visible light, it exhibits synergistically enhanced photothermal conversion efficiency and stability, owing to the localized surface plasmonic resonance effect of Au NP and Au-NS interactions. Moreover, under visible light irradiation for 10 min, the Au@ TiCT heterostructure exhibits excellent antibacterial activity for Gram-positive and Gram-negative , and kills over 99% bacteria with a low dose of the nanomedicine suspension (50 μg mL). The work demonstrates that the incorporation of transition metal carbides with plasmonic metal nanostructures is an effective strategy to enhance the photothermal antibacterial efficacy.