Strategies to Improve the Antimicrobial Efficacy of Photodynamic, Sonodynamic, and Sonophotodynamic Therapies

Background and Objectives This work evaluated antimicrobial photodynamic therapy (PDT), sonodynamic therapy (SDT), and the association of both therapies (sonophotodynamic therapy [SPDT]), mediated by curcumin (Cur) against Staphylococcus aureus biofilm. Next, additional strategies for these treatments were assessed. Materials and Methods S. aureus biofilms received PDT, SDT, and SPDT, mediated by Cur (80 µM), LED light (450 nm), and 1 MHz ultrasound. The same treatments were also performed adding a strategy: Cur with sodium dodecyl sulfate (SDS), Cur with potassium iodide (KI) or a pre‐treatment with ultrasound. Cell viability was determined and biofilm architecture was evaluated under confocal microscopy. Results SPDT was more effective to inactivate the bacteria than PDT and SDT. SDS achieved the greatest viability reductions, followed by KI and ultrasound pre‐treatment. Confocal images revealed biofilm disruption and a reduced number of cells in all treatments. However, SPDT exhibited a pronounced effect and it was greater using SDS. Conclusion SPDT was more effective and additional strategies potentiated its effectiveness. Lasers Surg. Med. © 2021 Wiley Periodicals LLC