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Size-dependent antimicrobial properties of sugar-encapsulated gold nanoparticles synthesized by a green method

Vivek D Badwaik1, Lakshmisri M Vangala1, Dillon S Pender1, Chad B Willis1, Zoraida P Aguilar2, Matthew S Gonzalez1, Rammohan Paripelly1 and Rajalingam Dakshinamurthy1*

Author Affiliations

1 Department of Chemistry, Western Kentucky University, Bowling Green, KY 4210, USA

2 Ocean Nano Tech, Springdale, AR 72764, USA

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Nanoscale Research Letters 2012, 7:623  doi:10.1186/1556-276X-7-623

Published: 12 November 2012

Abstract

The antimicrobial properties of dextrose-encapsulated gold nanoparticles (dGNPs) with average diameters of 25, 60, and 120 nm (± 5) and synthesized by green chemistry principles were investigated against both Gram-negative and Gram-positive bacteria. Studies were performed involving the effect of dGNPs on the growth, morphology, and ultrastructural properties of bacteria. dGNPs were found to have significant dose-dependent antibacterial activity which was also proportional to their size. Experiments revealed the dGNPs to be bacteriostatic as well as bactericidal. The dGNPs exhibited their bactericidal action by disrupting the bacterial cell membrane which leads to the leakage of cytoplasmic content. The overall outcome of this study suggests that green-synthesized dGNPs hold promise as a potent antibacterial agent against a wide range of disease-causing bacteria by preventing and controlling possible infections or diseases.

Keywords:
Gold nanoparticles; Green synthesis; Antibacterial activity; Propidium iodide; Outer membrane vesicles