The synergistic effect of photodynamic and sonodynamic inactivation against Candida albicans biofilm.

Candida albicans biofilm can cause diseases that are resistant to conventional antifungal agents. Photodynamic (PDI), sonodynamic (SDI), and sonophotodynamic (SPDI) inactivation have arisen as promising antimicrobial strategies. This study evaluated these treatments mediated by curcumin against C. albicans biofilms. For this, C. albicans biofilms were submitted to PDI, SDI, or SPDI with different light and ultrasound doses, then, the viability assay was performed to measure the effectiveness. Finally, a mathematical model was suggested to fit acquired experimental data and understand the synergistic effect of light and ultrasound in different conditions. The results showed that SPDI, PDI, and SDI reduced the viability in 6 ± 1; 1 ± 1; and 2 ± 1 log, respectively, using light at 60 J/cm2, ultrasound at 3 W/cm2, and 80 μM of curcumin. The viability reduction was proportional to the ultrasound and light doses delivered. These results encourage the use of SPDI for the control of microbial biofilm.