Photodynamic Therapy by Diaryl-Porphyrins to Control the Growth of Candida albicans

Abstract

Candida albicans is an opportunistic pathogen that often causes skin infections such as oral thrush, nail fungus, athlete’s foot, and diaper rash. Under particular conditions, C. albicans alters the natural balance of the host microbiota, and as a result, the skin or its accessory structures lose their function and appearance. Conventional antimycotic drugs are highly toxic to host tissues, and long-lasting drug administration induces the arising of resistant strains that make the antimycotic therapy ineffective. Among new antimicrobial approaches to combine with traditional drugs, light-based techniques are very promising. In this study, a panel of dyes was considered for photodynamic therapy (PDT) applications to control the growth of the model strain C. albicans ATCC 14053. The chosen photosensitizers (PSs) belong to the family of synthetic porphyrins, and in particular, they are diaryl-porphyrins. Among these, two monocationic PSs were shown to be particularly efficient in killing C. albicans upon irradiation with light at 410 nm, in a light-dose-dependent manner. The elicited photo-oxidative stress induced the loss of the internal cellular architecture and death. The photodynamic treatment was also successful in inhibiting the biofilm formation of clinical C. albicans strains. In conclusion, this study supports the great potential of diaryl-porphyrins in antimicrobial PDT to control the growth of yeasts on body tissues easily reachable by light sources, such as skin and oral cavity.

Photoinactivation of Pseudomonas aeruginosa Biofilm by Dicationic Diaryl-Porphyrin

“…Moreover, the eukaryotic microorganism Candida albicans showed to be sensitive in the dark to most cationic and dicationic diaryl-porphyrins tested in this study, irrespective of Soret band height [32]. Cormick reported that tri-and tetracationic porphyrins were more tightly bound to C. albicans cells than anionic porphyrins, supporting the requirement of positive charge on porphyrins to promote the electrostatic interaction with the yeast cell wall [41].…”

“…A panel of novel diaryl-porphyrins, synthetized by our group and previously tested as antimicrobials [33] antifungals [32] and antitumorals [31,34], was investigated for anti-Pseudomonas activity (Table 1). The neutral and asymmetrical P1 and P2 bear in mesopositions (positions 5 and 15) a pentafluorophenyl group, associated with a C4 or C8 para-bromoalkyloxy-phenyl group, respectively.…”

“…Among synthetic porphyrins, diaryl-porphyrins, bearing two substituents in two meso-positions, were shown to be efficient PSs both in antitumoral and in antifungal applications [31,32]. In the present study a panel of 5,15 meso-substituted diaryl-porphyrins was assayed for anti-biofilm activity.…”

Nitric Oxide Photo-Donor Hybrids of Ciprofloxacin and Norfloxacin: A Shift in Activity from Antimicrobial to Anticancer Agents

“…The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed on all the cell lines tested as previously described 52 with minor modifications. Briefly, according to the growth profiles previously defined for each cell line, adequate numbers of cells were plated in each well of a 96-well plate in 0.1 mL of complete culture medium.…”

Bodipy-Loaded Micelles Based on Polylactide as Surface Coating for Photodynamic Control of Staphylococcus aureus

“…After overnight incubation at 37 °C, coverslip glasses were irradiated under light at 520 nm for 2 h in a humid chamber. Upon irradiation, adherent cells were stained for 30 min with 2 μM fluorochrome 4,4-difluoro-1,3,5,7-tetramethyl-8-(2-methoxyphenyl)-4-bora-3a,4a-diaza-s-indacene [26]. Then, the coverslips were transferred on microscope glass slides for confocal microscopy analysis.…”