Issue 8, 2014

Size-controlled silver nanoparticles synthesized over the range 5–100 nm using the same protocol and their antibacterial efficacy

Abstract

A systematic and detailed study for size-specific antibacterial efficacy of silver nanoparticles (AgNPs) synthesized using a co-reduction approach is presented here. Nucleation and growth kinetics during the synthesis process was precisely controlled and AgNPs of average size 5, 7, 10, 15, 20, 30, 50, 63, 85, and 100 nm were synthesized with good yield and monodispersity. We found the bacteriostatic/bactericidal effect of AgNPs to be size and dose-dependent as determined by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of silver nanoparticles against four bacterial strains. Out of the tested strains, Escherichia coli MTCC 443 and Staphylococcus aureus NCIM 5201 were found to be the most and least sensitive strains regardless of AgNP size. For AgNPs with less than 10 nm size, the antibacterial efficacy was significantly enhanced as revealed through delayed bacterial growth kinetics, corresponding MIC/MBC values and disk diffusion tests. AgNPs of the smallest size, i.e., 5 nm demonstrated the best results and mediated the fastest bactericidal activity against all the tested strains compared to AgNPs having 7 nm and 10 nm sizes at similar bacterial concentrations. TEM analysis of AgNP treated bacterial cells showed the presence of AgNPs on the cell membrane, and AgNPs internalized within the cells.

Graphical abstract: Size-controlled silver nanoparticles synthesized over the range 5–100 nm using the same protocol and their antibacterial efficacy

Supplementary files

Article information

Article type
Paper
Submitted
20 Aug 2013
Accepted
22 Oct 2013
First published
01 Nov 2013
This article is Open Access
Creative Commons BY license

RSC Adv., 2014,4, 3974-3983

Size-controlled silver nanoparticles synthesized over the range 5–100 nm using the same protocol and their antibacterial efficacy

S. Agnihotri, S. Mukherji and S. Mukherji, RSC Adv., 2014, 4, 3974 DOI: 10.1039/C3RA44507K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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