Interaction of silver nanoparticles with model membranes: Possible role in the antibacterial activity.

FERREYRA MAILLARD, ANIKE PV; DALMASSO, PABLO R; DISALVO, ANIBAL,; HOLLMANN, AXEL

Santiago del Estero

Congreso; Reunión XLIV Sociedad Argentina de Biofisica; 2015

Sociedad Argentina de Biofisica

Silver and its compounds have shown strong bactericidal effects since ancient times. In recent years, nanotechnology has re-explored these biological properties by manipulating its size to alter the effects1. Thus, silver nanoparticles (SNPs) may be one of the approaches for overcoming bacterial resistance playing a key role in pharmacotherapeutics. However, the mechanism of the SNPs-mediated bactericidal effect remains still unknown. While several studies propose that the action of this nanomaterial could be related with membrane damage2 , the interaction between SNPs and the membrane is still unclear. In this context, the aim of this work was to characterize the interaction of SNPs with lipid layers as a membrane-mimetic model.The interactions were evaluated studying the surface pressure changes on both PC and PC:PG monolayers. Our results showed that SNPs can interact with these monolayers inducing an increase in the surface pressure. Despite the net negative charge of SNPs, it was surprisingly found that the negatively charged monolayers showed the highest changes. Since the surface charge density of SNPs may play a key role, zeta potential experiments were conducted finding that PC:PG liposomes became more negatives with the addition of SNPs. These results confirmed the interaction between SNPs and the membrane. Furthermore, the increased net negative charge of the liposomes indicates an interfacial interaction between SNPs and the membranes where the SNPs or at least a portion of them should keep adsorbed to the membrane. In this study, we probe that SNPs are able to interact with lipid membranes which allows to suggest that the SNPs-membrane interaction should be an essential step in the antibacterial activity either if the membrane is the main target or by increasing the local concentration of silver via SNPs accumulation that could cause the bactericidal effect.1Hajipour MJ et al.,Trends Biotechnol 30 (2012)499.2Eckhardt S, et al.,Chem Rev 113 (2013)4708.