Influence of photodynamic therapy combined with antimicrobial peptides on Candida albicans biofilm and 3D cell culture

Abstract

Antifungal resistance to conventional drugs is currently a challenge to control fungal infections. In this context, Antimicrobial Photodynamic Therapy (aPDT) has been investigated to control Candida albicans biofilms in order to inactivate microbial cells and weaken the Extracellular Matrix (ECM). Photodithazine (PDZ) is a Photosensitizer (PS), a second-generation e6 chlorin used in photodynamic inactivation with promising results. Antimicrobial Peptides (AMPs) also stand out in controlling the spread of infection, mainly for being of local application and act on multiple cellular targets, similar to aPDT. In order to develop a protocol to enhance the action of aPDT, the objective of this study will be to investigate the effect of PDZ-mediated aPDT combined with AMP(s) on susceptible (ATCC 90028; CaS) and resistant to fuconazole (ATCC 96901; CaR) C. albicans biofilm and human cells (Nok-si and FGH). The specific objectives will be: 1- analysis of the antimicrobial efficacy and mechanism of action of AMPs on planktonic cultures and CaS and CaR biofilms and their biocompatibility on human cells (NOK-si and FGH); 2- to evaluate the effect of aPDT (mediated by PDZ associated with LED light) with and without a combination of AMP(s) on CaS and CaR biofilms and their ECM; 3- analysis of gene expression of C. albicans cells surviving aPDT treatments (mediated by PDZ associated with LED light) combined with AMP(s); 4- to evaluate the effect of aPDT (mediated by PDZ associated with LED light) combined with AMP(s) on human cells (NOK-si and FGH) in a 3D co-culture model infected with C. albicans (CaS and CaR). All experiments will be performed using four replicates on three different occasions (n=12). The most appropriate statistical test will be applied respecting the assumptions established in the experimental design, considering a significance level of 5%. (AU)