Synthesis, characterization and photodynamic effects of polymeric nanoparticle-encapsulated curcumin on in vitro biofilms of Candida albicans and on a murine model of oral candidosis

Abstract

The aim of this study is to formulate and evaluate the photodynamic effect of curcumin (CUR) encapsulated in polymeric nanoparticles (NP) on in vitro biofilms of Candida albicans and on a murine model of oral candidosis. CUR-NP will be synthesized using poly-lactic acid (PLA), and dextran sulfate (DEX). To characterize this solution, the physicochemical properties (size, polydispersity and zeta potential) will be determined and tests of encapsulation efficiency, absorption spectrum, photostability (photodegradation of CUR) and photodynamic activity (photobleaching of singlet oxygen reagent and scavenger) will be also performed. Next, the effects of CUR-NP-mediated Photodynamic Therapy (PDT) against monospecies biofilms of C. albicans and polymicrobial biofilm of C. albicans associated with Streptococcus mutans and methicillin-resistant Staphylococcus aureus, cultured in vitro for 48 hours, will be assessed by quantification of colonies (CFU/mL), total biomass (crystal violet staining), scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). On CLSM, penetration of photosensitizer into the biofilm, cell viability, and structure of biofilm polymeric matrix will be analyzed. Each evaluation will be carried out in triplicate on three separate occasions and compared to free CUR. Additionally, the effectiveness of CUR-NP-mediated PDT will be evaluated in a murine model of oral candidiasis. Female mice (n = 35) will be immunosuppressed and inoculated with C. albicans to induce oral candidosis. After PDT, the fungal viability (CFU/mL) will be determined, the animals will be sacrificed and histological analysis of the tongue will be performed. Data will be statistically analyzed. (AU)