GOLD NANOPARTICLES: ANTIFUNGAL EFFECT AGAINST SESSIL AND PERSISTENT BIOFILMS CELLS

MARÍA A DA SILVA; PAULINA L PÁEZ.; IVANA L GALERA; MELISA A QUINTEROS; MARÍA G PARAJE

Workshop; 77th New England Workshop Complex Fluids; 2018

Centro de Ciencia e Ingeniería de Investigación de Materiales Universidad de Harvard

The recalcitrance exhibit by biofilm-associated infections, with sessile persister cells (PC) surviving in the presence of high concentrations of antifungal drugs (ATF), leads to treatment failure and infection recurrence. Novel strategies are necessary to achieve the complete eradication of biofilms and one promising approach to combating is based on nanotechnology. In this context, ATF activity of metallic nanoparticles (NP) was studied. Gold (Au) NP showed a percentage of biofilm reduction (% R) up to 90%, with an overproduction of reactive metabolites, mainly ROS. Antioxidant systems activation was not enough to avoid oxidative imbalance and biomass reduction. Comparison with Au NP conjugated to the antioxidant molecule cysteine (Au-cis NP), which showed a lower activity than the Au NP, evidenced a direct relationship between the observed ATF effect and the oxidative stress induction as a mechanism of action of NP. Finally, biomass and EPS matrix reduct ion and the impact on cellular morphology, was demonstrated by Scanning Electron Microscopy (SEM), observing multiple cell wall protuberances of sessile cells treated with Au NP.