Comparison of UV-Photocatalytic and Intrinsic Antifungal Activity of TiO₂ Nanoparticles aganist Candida tropicalis

This study aimed to evaluate the antifungal activity of titanium dioxide nanoparticles (TiO₂ NP) against Candida tropicalis ATCC 750 strain under both dark and UV light activation conditions. For this purpose, anatase phase TiO₂ nanoparticles were applied to C. tropicalis suspensions at four different concentrations (125, 250, 500, and 1000 µg/mL) and for four different durations (15, 30, 45, and 60 min). The experiments were conducted under two conditions: dark environment and UVA (365 nm- 15 cm distance) activation. Antifungal activity was determined by colony counting at the end of the exposure periods. Log reduction and percentage reduction were calculated. The UV+TiO₂ combination exhibited significantly higher antifungal activity compared to the dark condition. With UV activation, complete elimination (100% mortality, >2.48 log reduction) was observed at 45 minutes at a TiO₂ concentration of 1000 µg/mL and at 60 minutes at a concentration of 500 µg/mL. Under dark conditions, a maximum reduction of 0.84 log (85.7% reduction) was observed at 1000 µg/mL after 60 minutes; complete elimination was not observed at any concentration. Only 0.27 log reduction (46.7% reduction) was achieved after 60 minutes in the group treated with UV alone. Photocatalytic activity was found to be approximately 9 times stronger than the effect of UV alone. This study provides valuable evidence that UV-activated TiO₂ nanoparticles exhibit potent photocatalytic antifungal activity against C. tropicalis, with the potential to achieve complete elimination at high concentrations. The results obtained demonstrate that TiO₂ NPs have the potential to serve as an alternative antifungal strategy in the treatment of C. tropicalis infections, where resistance is becoming an increasingly significant problem.