In vitro evaluation of the cis-[Ru(phen) 2 (pPDIp)] 2+⁎⁎ complex for antimicrobial photodynamic therapy against Sporothrix brasiliensis and Candida albicans.

Background: Photodynamic therapy (PDT) activates a photosensitizer by visible light to generate cytotoxic oxygen species that lead to cell death. With proper illumination, PDT is often used in applications on superficial and sub-surface lesions. Sporotrichosis infection occurs by Sporothrix fungi which causes a skin wound, worsened by Candida albicans infections. This study investigated the photosensitizing efficiency of the Ru(phen) ₂ (pPDIp)(PF ₆ ) ₂ complex, RupPDIp, against S. brasiliensis and C. albicans.
Material and Methods: RupPDIp efficiency against these fungi was tested using 450 nm (blue light and 36 J/cm ² ) and 525 nm (green light, 25.2 J/cm ² ) at 0.05-20 μM concentrations. To ensure PDT effectiveness, control groups were tested in the absence and in the presence of RupPDIp under light irradiation and in the dark.
Results: RupPDIp eliminated both fungi at ≤5.0 μM. Green light showed the best results, eliminating S. brasiliensis and C. albicans colonies at RupPDIp 0.5 μM and 0.05 μM, respectively.
Conclusion: RupPDIp is a promising photosensitizer in aPDT, eliminating 10 ⁶  CFU/mL of both fungi at 450 nm and 525 nm, with lower light doses and concentrations when treated with the green light compared to the blue light.
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