Sensitivity of bacteria to diamond nanoparticles of various size differs in gram-positive and gram-negative cells

• Published in: FEMS microbiology letters 2014-02, Vol.351 (2), p.179-186
• Main Authors: Beranová, Jana, Seydlová, Gabriela, Kozak, Halyna, Benada, Oldřich, Fišer, Radovan, Artemenko, Anna, Konopásek, Ivo, Kromka, Alexander
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; antibacterial properties; Bacillus subtilis; Bacillus subtilis - cytology; Bacillus subtilis - drug effects; Bacillus subtilis - physiology; Chemical Phenomena; Colony Count, Microbial; Diamond; diamond nanoparticles; DLS; E coli; Escherichia coli; Escherichia coli - cytology; Escherichia coli - drug effects; Escherichia coli - physiology; Light scattering; Microbial Viability - drug effects; Microbiology; Microscopy, Electron, Transmission; Nanoparticles; X-ray diffraction; XPS
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/1574-6968.12373

Abstract In this study, the influence of the size and surface termination of diamond nanoparticles (DNPs) on their antibacterial activity against Escherichia coli and Bacillus subtilis was assessed. The average size and distribution of DNPs were determined by dynamic light scattering and X-ray diffraction techniques. The chemical composition of the DNPs studied by X-ray photoelectron spectroscopy showed that DNPs > 5 nm and oxidized particles have a higher oxygen content. The antibacterial potential of DNPs was assessed by the viable count method. In general, E. coli exhibited a higher sensitivity to DNPs than B. subtilis. However, in the presence of all the DNPs tested, the B. subtilis colonies exhibited altered size and morphology. Antibacterial activity was influenced not only by DNP concentration but also by DNP size and form. Whereas untreated 5-nm DNPs were the most effective against E. coli, the antibacterial activity of 18–50-nm DNPs was higher against B. subtilis. Transmission electron microscopy showed that DNPs interact with the bacterial surface, probably affecting vital cell functions. We propose that DNPs interfere with the permeability of the bacterial cell wall and/or membrane and hinder B. subtilis colony spreading. The antibacterial activity of diamond nanoparticles depends both on the size and surface termination of the nanoparticles and also on the structure of the bacterial cell wall.