The Impact of Bacteria Exposure on the Plasmonic Response of Silver Nanostructured Surfaces

TL;DR

This study investigates how bacteria exposure alters the plasmonic properties of silver nanostructures, revealing changes in spectral and dynamical features due to bacteria-induced oxidative dissolution, with implications for bio-responsive material applications.

Contribution

It provides the first detailed analysis of bacteria-induced plasmonic response changes in silver nanostructures using ultrafast pump-probe measurements.

Findings

Bacteria exposure causes significant changes in plasmon spectral features.

Oxidative dissolution from bacteria alters nanoparticle size, shape, and crystallinity.

Plasmonic responses can serve as biophysical signatures of bacterial interaction.

Abstract

Silver, especially in the form of nanostructures, is widely employed as an antimicrobial agent in a large range of commercial products. The origin of the biocidal mechanism has been elucidated in the last decades, and most likely originates from silver cation release due to oxidative dissolution followed by cellular uptake of silver ions, a process that causes a severe disruption of bacterial metabolism and eventually leads to eradication. Despite the large number of works dealing with the effects of nanosilver shape/size on the antibacterial mechanism and on the (bio)physical chemistry pathways that drive bacterial eradication, little effort has been devoted to the investigation of the silver NPs plasmon response upon interaction with bacteria. Here we present a detailed investigation of the bacteria-induced changes of the plasmon spectral and dynamical features after exposure to one of the most studied bacterial models, Escherichia Coli. Ultrafast pump-probe measurements indicate that the dramatic changes on particle size/shape and crystallinity, which stem from a bacteria-induced oxidative dissolution process, translate into a clear modification of the plasmon spectral and dynamical features. This study may open innovative new avenues in the field of biophysics of bio-responsive materials, with the aim of providing new and reliable biophysical signatures of the interaction of these materials with complex biological environments.