Efficient photodynamic inactivation ofCandida albicansby porphyrin and potassium iodide co-encapsulation in micelles

摘要

Photodynamic inactivation of bacterial and fungal pathogens is a promising alternative to the extensive use of conventional single-target antibiotics and antifungal agents. The combination of photosensitizers and adjuvants can improve the photodynamic inactivation efficiency. In this regard, it has been shown that the use of potassium iodide (KI) as adjuvant increases pathogen killing. Following our interest in this topic, we performed the co-encapsulation of a neutral porphyrin photosensitizer (designated asP1) and KI into micelles and tested the obtained nanoformulations against the human pathogenic fungusCandida albicans. The results of this study showed that the micelles containingP1and KI displayed a better photodynamic performance towardsC. albicansthanP1and KI in solution. It is noteworthy that higher concentrations of KI within the micelles resulted in increased killing ofC. albicans. Subcellular localization studies by confocal fluorescence microscopy revealed thatP1was localized in the cell cytoplasm, but not in the nuclei or mitochondria. Overall, our results show that a nanoformulation containing a photosensitizer plus an adjuvant is a promising approach for increasing the efficiency of photodynamic treatment. Actually, the use of this strategy allows a considerable decrease in the amount of both photosensitizer and adjuvant required to achieve pathogen killing.