Sterile 24 well polystyrene microplate

After PDI treatment, yeast suspensions were transferred into the wells of a sterile 24-well polystyrene microplate (Corning, USA) that contained sterile glass coverslips and incubated at 37°C for 1 h. The coverslips were gently washed with PBS three times and fixed in 2.5% glutaraldehyde at 4°C for 2 h. Then, the coverslips were washed with PBS three times and fixed in 1% osmium tetroxide at 4°C for 2 h. After dehydration with ethanol gradients, the samples were freeze-dried, sputter-coated with gold, and observed using an SEM (Hitachi TM-1000, Japan).

A bacterial suspension (2 mL; 1 × 10 6 CFU/mL) was inoculated into the wells of a sterile 24-well polystyrene microplate (Corning, USA) that contained sterile glass coverslips and incubated at 37°C for 24 h. The culture medium was removed and the biofilms on coverslips were gently washed twice with PBS to remove loosely adherent bacteria. Then, the coverslips were removed with sterilized forceps and placed into the wells of a new 24-well microplate containing 2 mL 10 mM 5-ALA or MAL. The microplate was incubated at 37°C for 4 h in the dark. After irradiation for 60 min, the coverslips were gently washed twice with PBS and placed into the wells of another 24-well microplate. The biofilms were resuspended in 2 mL of PBS and dislodged by ultrasonication (Hangzhou Front Ultrasoni FRQ-1002T, China) for 10 min, followed by rapid vortexing with a vortex mixer (Haimen Qilinbeier QL-901, China) for 1 min. Bacterial suspensions were serially 10-fold diluted with PBS, and 20 μL of each dilution was plated in triplicate on TSA. Colonies were counted after 24 h incubation at 37°C.