Antimicrobial Gold Nanoclusters

Abstract

Bulk gold (Au) is known to be chemically inactive. However, when the size of Au nanoparticles (Au NPs) decreases to close to 1 nm or sub-nanometer dimensions, these ultrasmall Au nanoclusters (Au NCs) begin to possess interesting physical and chemical properties and likewise spawn different applications when working with bulk Au or even Au NPs. In this study, we found that it is possible to confer antimicrobial activity to Au NPs through precise control of their size down to NC dimension (typically less than 2 nm). Au NCs could kill both Gram-positive and Gram-negative bacteria. This wide-spectrum antimicrobial activity is attributed to the ultrasmall size of Au NCs, which would allow them to better interact with bacteria. The interaction between ultrasmall Au NCs and bacteria could induce a metabolic imbalance in bacterial cells after the internalization of Au NCs, leading to an increase of intracellular reactive oxygen species production that kills bacteria consequently.

Gold Nanoclusters for Targeting Methicillin‐Resistant Staphylococcus aureus In Vivo

“…[6,7] Unlike gold nanoparticles (AuNPs), smaller gold nanoclusters (AuNCs) have recently emerged as innovative nanomedicines with interesting properties,s uch as size-dependent fluorescence. [11] However,studies describing the effect of AuNCs on MDR bacteria are scarce,p articularly for combating MDR bacteria in vivo. [11] However,studies describing the effect of AuNCs on MDR bacteria are scarce,p articularly for combating MDR bacteria in vivo.…”

Antimicrobial Nanoparticles: applications and mechanisms of action

“…Gold NPs less than 2nm have shown strong antibacterial activity. 27 It is speculated that the antimicrobial activity of AuNPs reported in some studies may be due to the bactericidal activity of co-existing chemicals not completely removed from AuNPs during synthesis. However, photo thermal therapy (PTT) offers a promising new approach for improving the bactericidal potential of AuNPs.…”

Metal Nanoparticles for Diagnosis and Therapy of Bacterial Infection

“…Increased ROS generation under NIR or UV light irradiation and lightenhanced metal-based NPs will be reviewed in the next section. [78] In this study, when the particle size was reduced down to <2 nm, Au NCs were found to display strong antimicrobial activity toward both Gram-positive and Gram-negative bacteria. Compared with Ag and Cu NPs, Au NPs are much more inert and biocompatible, and therefore potentially more promising therapeutic antimicrobial agents.…”