2.7. Minimum Bactericidal Concentration (MBC) Assays

S. aureus (10⁶ CFU/mL) was incubated in a copper chloride solution at various concentrations (10 μM - 1 M) in media on a 96-well microtiter plate (100 μL per well) for 24 h. Bacteria was incubated with PBS alone as a control. After incubation, the bacteria were diluted at 1:10¹ to 1:10⁵ with PBS. The number of bacteria was quantified by spotting the dilution (5 μL) on an agar plate supplemented with media for the counting of CFUs.