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.