title: Sensitivity of bacteria to diamond nanoparticles of various size differs in gram-positive and gram-negative cells.
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.
authors.affiliation: Institute of Physics v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Beranová
authors.forename: Gabriela
authors.initials: G
authors.lastname: Seydlová
authors.forename: Halyna
authors.initials: H
authors.lastname: Kozak
authors.forename: Oldřich
authors.initials: O
authors.lastname: Benada
authors.forename: Radovan
authors.initials: R
authors.lastname: Fišer
authors.forename: Anna
authors.initials: A
authors.lastname: Artemenko
authors.forename: Ivo
authors.initials: I
authors.lastname: Konopásek
authors.forename: Alexander
authors.initials: A
authors.lastname: Kromka
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D055598:Chemical Phenomena; D015169:Colony Count, Microbial; D018130:Diamond; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D050296:Microbial Viability / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles
chemical_list: D000900:Anti-Bacterial Agents; D018130:Diamond
keywords: Bacillus subtilis; DLS; Escherichia coli; XPS; antibacterial properties; diamond nanoparticles