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)(PF6)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/cm2) and 525 nm (green light, 25.2 J/cm2) 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 106 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.

Evaluation of vascular effect of Photodynamic Therapy in chorioallantoic membrane using different photosensitizers.

Photodynamic Therapy (PDT) is a local treatment that requires a photosensitizing agent, light and molecular oxygen. With appropriate illumination, the photosensitizer is excited and produces singlet oxygen that is highly reactive and cytotoxic. Tumor vascular network is essential for the tumor growth and the understanding of vascular response mechanisms enables an improvement in the PDT protocol for cancer treatment. Compounds of porphyrin (Photogem®) and chlorin (Photodithazine®) were the photosensitizers tested. The incubation times varied from 20 to 80 min and the concentration ranged between 0.1 and 100 µg/cm(2). Different light doses were used between 4.8 and 40 J/cm(2) with irradiance varying between 80 and 100 mW/cm(2). The light dose of 30 J/cm(2) was used in the intravenous photosensitizer application. The membrane images were made from 0 to 300 min after treatment. The vascular response was evaluated by the average vessel area. Different responses was observed depending on the photosensitizer concentration and administration form. Intravenous application has been more efficient to produce vessel constriction and the most pronounced effect was observed for the chlorin.