Magnetic nanoparticles for mature biofilm disruption

DIEGO PISSINIS; CAROLINA VERICAT; CAROLINA DIAZ; MARIANO FONTICELLI; GABRIEL LAVORATO; PATRICIA L. SCHILARDI

Quimes (virtual)

Jornada; 1st zooming into preclinal nanomedicines in the era of Covid 19; 2020

Asociación Argentina de Nanomedicinas

Healthcare-associated infections (HAIs) are a serious global public health problem. Biofilms are responsible of the majority of medical device related HAIs. Biofilms are communities of microorganisms protected by self-produced extracellular polymeric substances (EPSs). The matrix of EPS is the main reason for the tolerance of biofilm against many antimicrobial agents. Penetration of biofilms remains a challenge at the moment of treating biofilms: standard antibiotics and disinfectants are often ineffective in eradicating biofilms. Recently, several research groups have used magnetic iron-oxide nanoparticles (MNPs) as a tool to penetrate and disrupt mature biofilms. This innovative strategy still need to be exhaustively investigated to unravel penetration and disruption biofilm mechanisms. In the present work we have used 20 nm MNPs prepared by an organic phase synthesis route and functionalized to provide a stable aqueous suspension with negatively charged surfaces. We have combined the MNPs treatment on mature biofilms with subsequent employment of conventional antibiotics and silver nanoparticles (AgNPs). The complete procedure has been investigated by atomic force microscopy, confocal microscopy, microbiological methods and magnetophoretic experiments. The results of this research confirmed that the interaction of MNPs with EPS works as an exfoliative treatment, removing bacterial layers from the biofilms structure. As a consequence, biofilm turns out to be more labile and antimicrobial agents can now improve their efficacy.