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Journal of Chemistry
Volume 2016, Article ID 4143560, 8 pages
Research Article

Ultrasmall, Ligand-Free Ag Nanoparticles with High Antibacterial Activity Prepared by Pulsed Laser Ablation in Liquid

1Research Institute for Viticulture and Oenology, University of Pécs, Pázmány Péter Utca 4, Pécs 7634, Hungary
2Department of Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova, Italy
3Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros Utca 2, Pécs 7632, Hungary

Received 27 January 2016; Revised 9 April 2016; Accepted 11 April 2016

Academic Editor: Chellappan R. Raj

Copyright © 2016 László Kőrösi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Since ancient times, silver and its compounds have been known to have a broad spectrum of antimicrobial activities for bacteria, fungi, and viruses. Due to the increasing bacterial resistance to classic antibiotics, the investigations of Ag NPs have increased. Herein, we present the preparation of ligand-free Ag NPs with 3 and 20 nm sizes by applying picosecond laser ablation in liquid at 355 and 1065 nm. Our laser processing system allows a high control on particle sizes. The produced nanoparticles were characterized by means of transmission electron microscopy, UV-Vis spectroscopy, and X-ray diffraction. The size effect on the antibacterial activity of Ag NPs was tested against E. coli and S. aureus. The growth curves of bacteria were monitored at 0–5 mg/L of Ag NPs by a multimode microplate reader. The size effects as well as the concentration of Ag NPs on their antibacterial activity are discussed.