In vitro study on the effects of photodynamic inactivation using methyl pheophorbide a, PhotoMed, PhotoCure, and 660 nm diode laser on Candida albicans

Abstract

Background: Candida albicans (C. albicans) is the most common fungal pathogen that causes clinical infections in humans. This study aimed to evaluate the effects of photodynamic inactivation (PDI) using a 660 nm diode laser along with methyl pheophorbide a, PhotoMed, and PhotoCure as photosensitizer for analyzing the viability of in vitro inactivation of C. albicansMethods: In the PDI group, 20 μL of C. albicans suspension and 20 μL of photosensitizer were inoculated in a 90 mm petri dish (63.6 cm2). The samples were placed in an incubator at 37 °C for 30 min, and then they were irradiated with light (660 nm diode laser, 3 J/cm2). After laser irradiation, the cells were stored for 48 h at 37 °C in an incubator with 5% CO2, and the number of colonies was counted.Results: The highest reduction in the number of colony-forming units per milliliter (CFU/mL) after PDI was observed in the presence of methyl pheophorbide a and PhotoMed, followed by PhotoCure. One-way analysis of variance (ANOVA) demonstrated a significant inhibition (F = 384.717; P < 0.05) for each PDI.Conclusions: In this study, we demonstrated that the application of PDI to C. albicans using methyl pheophorbide a and PhotoMed resulted in 100% death rates.PDI could be a treatment method because conventional antifungals have limited effects, and they may not eliminate C. albicans completely.