Photothermal Heating‐Assisted Superior Antibacterial and Antibiofilm Activity of High‐Entropy‐Alloy Nanoparticles

Abstract Antibacterial elements and non‐contact heating abilities have been proven effective for antibacterial and antibiofilm activities, but it remains a challenge to integrate both within one material. Herein, assisted by the high‐entropy effect, FeNiTiCrMnCu x high‐entropy alloy nanoparticles (HEA‐NPs) with excellent photothermal heating properties for boosting antibacterial and antibiofilm performances are synthesized. Benefitting from the synergetic effect of copper ions released and thermal damage by the HEA‐NPs, more reactive oxygen species (ROS) are generated, leading to the rupture of the cell membranes and the eradication of the biofilms. As a result, the antibiofilm efficiency (400 µg mL −1 ) of the mostly optimized FeNiTiCrMnCu 1.0 HEA‐NPs in the marine nutrient medium, which is the worst‐case scenario for the antimicrobial material, can be improved from 81% to 97.4% under 30 min solar irradiation (1 sun). The present study demonstrates a new strategy for effectively treating marine microorganisms that cause biofouling and microbial corrosion using HEA‐NPs with photothermal heating characteristics as an antibacterial auxiliary.