BSA nanoparticles loaded-methylene blue for photodynamic antimicrobial chemotherapy (PACT): effect on both growth and biofilm formation byCandida albicans

It has been demonstrated an increase in resistance ofCandida albicansto conventional therapies, probably, due the indiscriminate use of the conventional antifungal drugs. In this aspect, the nanotechnology generates the possibility of creating new therapeutic agents. Thus, the objective of this paper was to produce and characterize a bovine serum albumin (BSA) nanoparticle encapsulated with Methylene Blue (MB). In addition, the effect of BSA nanoparticles encapsulated with MB (BSA-MB) was evaluated on both growth and biofilm formation byC. albicansby Photodynamic Antimicrobial Chemotherapy (PACT) protocols. The BSA-MB nanoparticles were prepared by the desolvation process. The nanoparticulate system was studied by steady-state techniques, scanning electron microscopy and their biological activity was evaluatedin vitroboth growth and biofilm formation byC. albicans. The synthetized BSA-MB nanoparticles were spherical in shape exhibiting a 100-200 nm diameter with a low tendency to aggregate (PDI values < 0.2). MB photophysical properties were shown to be preserved after BSA encapsulation. A significant reduction inC. albicansgrowth, after PACT was observed, in a dependent manner on MB-loaded in BSA nanoparticles concentration used. It was observed an inhibition of 23, 65 and 83% in the presence of MB-loaded in BSA nanoparticles 0.1, 0.5 and 1.0 mu g.mL(-1), respectively. In addition, MB-loaded BSA nanoparticles 0.5 mu g.mL(-1)were able to reduce both biofilm formation (80%) and the transition from yeast to filamentous form byC. albicans. The results presented here demonstrated a potentiation of the phototoxic effect of MB after BSA encapsulation, since the concentrations of MB-loaded BSA nanoparticles necessary to inhibits similar to 50% ofC. albicansdevelopment was 10 times minor than that observed for free MB. Taken together, these results suggest the potential of PACT, using MB-loaded BSA nanoparticles in inhibitingC. albicansdevelopment. The synthesis and design of BSA nanoparticles can be successfully applied for MB encapsulation and offer the possibility to drive the toxicity effect to a specific target, as an evaluation on both growth and biofilm formation byCandida albicans.