Issue 22, 2016

Silver nanoparticles with different size and shape: equal cytotoxicity, but different antibacterial effects

Abstract

The influence of silver nanoparticle morphology on the dissolution kinetics in ultrapure water as well as the biological effect on eukaryotic and prokaryotic cells was examined. Silver nanoparticles with different shapes but comparable size and identical surface functionalisation were prepared, i.e. spheres (diameter 40–80 and 120–180 nm; two different samples), platelets (20–60 nm), cubes (140–180 nm), and rods (diameter 80–120 nm, length > 1000 nm). All particles were purified by ultracentrifugation and colloidally stabilized with poly(N-vinyl pyrrolidone) (PVP). Their colloidal dispersion in ultrapure water and cell culture medium was demonstrated by dynamic light scattering. Size, shape, and colloidal stability were analysed by scanning electron microscopy, atomic force microscopy, dynamic light scattering, and differential centrifugal sedimentation. The dissolution in ultrapure water was proportional to the specific surface area of the silver nanoparticles. The averaged release rate for all particle morphologies was 30 ± 13 ng s−1 m−2 in ultrapure water (T = 25 ± 1 °C; pH 4.8; oxygen saturation 93%), i.e. about 10–20 times larger than the release of silver from a macroscopic silver bar (1 oz), possibly due to the presence of surface defects in the nanoparticulate state. All particles were taken up by human mesenchymal stem cells and were cytotoxic in concentrations of >12.5 μg mL−1, but there was no significant influence of the particle shape on the cytotoxicity towards the cells. Contrary to that, the toxicity towards bacteria increased with a higher dissolution rate, suggesting that the toxic species against bacteria are dissolved silver ions.

Graphical abstract: Silver nanoparticles with different size and shape: equal cytotoxicity, but different antibacterial effects

Supplementary files

Article information

Article type
Paper
Submitted
27 Dec 2015
Accepted
08 Feb 2016
First published
09 Feb 2016
This article is Open Access
Creative Commons BY license

RSC Adv., 2016,6, 18490-18501

Silver nanoparticles with different size and shape: equal cytotoxicity, but different antibacterial effects

J. Helmlinger, C. Sengstock, C. Groß-Heitfeld, C. Mayer, T. A. Schildhauer, M. Köller and M. Epple, RSC Adv., 2016, 6, 18490 DOI: 10.1039/C5RA27836H

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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