title: A critical study: assessment of the effect of silica particles from 15 to 500 nm on bacterial viability.
abstract: The current opinion on the toxicity of nanomaterials converges on a size-dependent phenomenon showing increasing toxicity with decreasing particle sizes. We demonstrate that SiO2 particles have no or only a mild effect on the viability of five bacterial strains, independently from the particle size. A two-hour exposure to 20 mg L(-1) of 15, 50 and 500 nm sized SiO2 particles neither alters bacterial adenosine triphosphate (ATP) levels nor reduces the number of colony forming units (CFU). Additionally, we tested the effect of Al2O3-coated LUDOX-CL (ACS 20) with a primary particle size of 20 nm. In contrast, these particles caused a significant reduction of ATP levels and CFU. Fluorescence microscopy revealed that ACS 20 induced a pronounced agglomeration of the bacteria, which led to underestimated counts in regard of CFU. Bactericide effects as indicated by decreased ATP levels can be explained by bactericide additives that are present in the ACS 20 suspension.
authors: Advanced Ceramics, University of Bremen, Am Biologischen Garten 2, 28359 Bremen, Germany.
authors: Julia
authors: J
authors: Wehling
authors: Eike
authors: E
authors: Volkmann
authors: Tim
authors: T
authors: Grieb
authors: Andreas
authors: A
authors: Rosenauer
authors: Michael
authors: M
authors: Maas
authors: Laura
authors: L
authors: Treccani
authors: Kurosch
authors: K
authors: Rezwan
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D004785:Environmental Pollutants / Q000633:toxicity*; D050296:Microbial Viability; D049329:Nanostructures / Q000633:toxicity*; D010316:Particle Size; D018570:Risk Assessment; D012822:Silicon Dioxide / Q000633:toxicity*
chemical_list: D004785:Environmental Pollutants; D012822:Silicon Dioxide; D000251:Adenosine Triphosphatases