Infectious pathogens cause severe threats to public health due to their frightening infectivity and lethal capacity. Rapid and accurate detection of pathogens is of great significance for preventing their infection. Gold nanoparticles have drawn considerable attention in colorimetric biosensing during the past decades due to their unique physicochemical properties. Colorimetric diagnosis platforms based on functionalized AuNPs are emerging as a promising pathogen-analysis technique with the merits of high sensitivity, low-cost, and easy operation. This review summarizes the recent development in this field. We first introduce the significance of detecting pathogens and the characteristics of gold nanoparticles. Four types of colorimetric strategies, including the application of indirect target-mediated aggregation, chromogenic substrate-mediated catalytic activity, point-of-care testing (POCT) devices, and machine learning-assisted colorimetric sensor arrays, are systematically introduced. In particular, three biomolecule-functionalized AuNP-based colorimetric sensors are described in detail. Finally, we conclude by presenting our subjective views on the present challenges and some appropriate suggestions for future research directions of colorimetric sensors.

Bacterial infections have become a major problem threatening public health, and it is of great significance to treat wound infections in biological systems caused by bacteria. However, traditionally used bacteriostatic agents usually cause additional pollution. Herein a mushroom-shaped clean and Green BiFeO₃/g-C₃N₄ composite is employed for the first time for photocatalytic antibacterial activity and for the further promotion of wound healing. The ratio between BiFeO₃ and g-C₃N₄ was delicately regulated to control the generated amount of ˙OH and ˙O₂ ⁻ by catalyzing the decomposition of hydrogen peroxide (H₂O₂) under illumination. Results show that 10%BFO/CN demonstrates the best performance for ˙OH and ˙O₂ ⁻ production, resulting in the highest antibacterial ability against E. coli and S. aureus. In addition, the catalytic mechanism of BiFeO₃/g-C₃N₄ towards antibacterial activity is disclosed by a combination of ESR monitoring and analysis of the Mott–Schottky diagram. Furthermore, in vivo experiments prove that 10%BFO/CN can effectively promote anti-infection and wound healing in nude mice. This work sheds deep scientific insight on the synergistic effect of photocatalysis and photo-Fenton degradation as well as their application in antibacterial and wound therapeutic activity.