1：Experimental Design and Method Selection:

The study involved preparing Au/TiO2 nanoparticles via photocatalytic reduction, characterizing them using spectroscopy and microscopy, and conducting femtosecond laser spectroscopy to observe electron injection. Bacterial inactivation experiments were performed under visible light irradiation, and the effects of Au ions on bacterial growth and biofilms were assessed using microbiological methods.

2：Sample Selection and Data Sources:

Samples included Au/TiO2 nanoparticles, various Gram-negative bacterial strains (E. coli AB1157, P. aeruginosa PAO1, S. proteamaculans 94), and chemicals like HAuCl4. Data were sourced from laboratory experiments and measurements.

3：Data were sourced from laboratory experiments and measurements. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included femtosecond laser setup (Spectra-Physics), spectrophotometer, electron microscopes (Zeiss SEMs, LEO TEM), LED light sources (Nichia), tungsten-halogen lamp, centrifuges, microplate reader (Bio-Rad), confocal microscope (Zeiss LSM 510). Materials included TiO2 P25, HAuCl4, methanol, PEG4000, bacterial culture media, and chemicals for nanoparticle synthesis.

4：0). Materials included TiO2 P25, HAuCl4, methanol, PEG4000, bacterial culture media, and chemicals for nanoparticle synthesis. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Procedures involved nanoparticle synthesis, irradiation with light sources, measurement of transient absorption spectra, bacterial culture and inactivation kinetics, biofilm formation assays, and statistical analysis. Steps included centrifugation, washing, irradiation, and data collection at specified time points.

5：Data Analysis Methods:

Data were analyzed using statistical methods (mean, standard deviation, Student's t-test) with Microsoft Excel software, and spectral data were corrected for group delay dispersion.