1：Experimental Design and Method Selection:

The study aimed to evaluate the synergistic effects of low-power density laser light and naked gold nanoparticles on bacterial inactivation. Methods included photodynamic inactivation assays, singlet oxygen detection using DPBF bleaching, and characterization of nanoparticles.

2：Sample Selection and Data Sources:

Escherichia coli ATCC 25922 was used as the model microorganism. Gold nanoparticles were purchased from PNF company, and various concentrations were prepared by dilution.

3：List of Experimental Equipment and Materials:

Equipment included a TEM microscope (Philips CM30), DLS instrument (Cordouan Technology), UV-visible spectrophotometer (Spekol 2000, Analyticjena CO), CW Nd:Yag laser (CNI Laser, model MGL-III-532), beam expander, infrared thermometer, shaker incubator (FF-81, ParsAzma Co.), and statistical software (SigmaPlot 12.0). Materials included gold nanoparticles, DPBF (Sigma-Aldrich), nutrient broth, saline solution, and deionized water.

4：0). Materials included gold nanoparticles, DPBF (Sigma-Aldrich), nutrient broth, saline solution, and deionized water. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Gold nanoparticles were characterized using TEM and DLS. Singlet oxygen generation was assessed by monitoring DPBF absorbance changes under laser illumination. Bacterial cultures were prepared and exposed to laser light with and without gold nanoparticles at various concentrations and exposure times. Viability was assessed through colony counting after serial dilution and incubation.

5：Data Analysis Methods:

Statistical analysis was performed using one-way ANOVA and Tukey post hoc test with SigmaPlot software, considering results with P < 0.05 as significant.