Silver nanoparticle-protein interactions and the role of lysozyme as an antagonistic antibacterial agent

DORADO, RITA D.; ESPECHE TURBAY, M. BEATRIZ; SOSA, MARCELO C.; REY, VALENTINA; BORSARELLI, CLAUDIO D.

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Año: 2021 vol. 208

0927-7765

The photoreductive synthesis and antibacterial activity of silver nanoparticles (AgNP) prepared in the presence of bovine serum albumin (BSA) and lysozyme (LZ) were evaluated. AgNP@BSA showed similar antibacterial activity to those stabilized with citrate (AgNP@CIT) and to an AgNO3 solution, suggesting the releases of Ag+ as the mechanism of death. In contrast, AgNP@LZ solutions showed no activity, although LZ behaves as a moderately antibacterial peptide. Furthermore, the addition of LZ to the AgNP@CIT or AgNP@BSA solutions induced their agglomeration and suppressed their original antibacterial efficacy. This antagonistic antibacterial effect exerted by LZ on AgNPs is associated with electrostatic interactions exerted by LZ. Specific metal-LZ interactions produce a harder protein corona on AgNP@LZ that retains Ag+, while LZ acts as a glue for AgNP@CIT or AgNP@LZ due to its opposite electrical charge, besides strong binding to Ag+avoiding the bactericide effect. Therefore, bactericidal effects of AgNP in biological media may be modulated by specific protein interactions.