TY - JOUR
T1 - Can disc diffusion susceptibility tests assess the antimicrobial activity of engineered nanoparticles?
AU - Kourmouli, Angeliki
AU - Valenti, Marco
AU - van Rijn, Erwin
AU - Beaumont, Hubertus J.E.
AU - Kalantzi, Olga Ioanna
AU - Schmidt-Ott, Andreas
AU - Biskos, George
PY - 2018
Y1 - 2018
N2 - The use of disc diffusion susceptibility tests to determine the antibacterial activity of engineered nanoparticles (ENPs) is questionable because their low diffusivity practically prevents them from penetrating through the culture media. In this study, we investigate the ability of such a test, namely the Kirby-Bauer disc diffusion test, to determine the antimicrobial activity of Au and Ag ENPs having diameters from 10 to 40 nm on Escherichia coli cultures. As anticipated, the tests did not show any antibacterial effects of Au nanoparticles (NPs) as a result of their negligible diffusivity through the culture media. Ag NPs on the other hand exhibited a strong antimicrobial activity that was independent of their size. Considering that Ag, in contrast to Au, dissolves upon oxidation and dilution in aqueous solutions, the apparent antibacterial behavior of Ag NPs is attributed to the ions they release. The Kirby-Bauer method, and other similar tests, can therefore be employed to probe the antimicrobial activity of ENPs related to their ability to release ions rather than to their unique size-dependent properties. [Figure not available: see fulltext.].
AB - The use of disc diffusion susceptibility tests to determine the antibacterial activity of engineered nanoparticles (ENPs) is questionable because their low diffusivity practically prevents them from penetrating through the culture media. In this study, we investigate the ability of such a test, namely the Kirby-Bauer disc diffusion test, to determine the antimicrobial activity of Au and Ag ENPs having diameters from 10 to 40 nm on Escherichia coli cultures. As anticipated, the tests did not show any antibacterial effects of Au nanoparticles (NPs) as a result of their negligible diffusivity through the culture media. Ag NPs on the other hand exhibited a strong antimicrobial activity that was independent of their size. Considering that Ag, in contrast to Au, dissolves upon oxidation and dilution in aqueous solutions, the apparent antibacterial behavior of Ag NPs is attributed to the ions they release. The Kirby-Bauer method, and other similar tests, can therefore be employed to probe the antimicrobial activity of ENPs related to their ability to release ions rather than to their unique size-dependent properties. [Figure not available: see fulltext.].
KW - Aerosol-based nanoparticle synthesis
KW - Antimicrobial activity
KW - Disc diffusion method
KW - Engineered nanoparticles
KW - Gold nanoparticles
KW - Silver nanoparticles
UR - http://www.scopus.com/inward/record.url?scp=85042879258&partnerID=8YFLogxK
UR - http://resolver.tudelft.nl/uuid:7e2f0498-f4e3-49e3-8c91-23c0118a3f1b
U2 - 10.1007/s11051-018-4152-3
DO - 10.1007/s11051-018-4152-3
M3 - Article
AN - SCOPUS:85042879258
SN - 1388-0764
VL - 20
JO - Journal of Nanoparticle Research: an interdisciplinary forum for nanoscale science and technology
JF - Journal of Nanoparticle Research: an interdisciplinary forum for nanoscale science and technology
IS - 3
M1 - 62
ER -