title: Bacterial toxicity comparison between nano- and micro-scaled oxide particles.
abstract: Toxicity of nano-scaled aluminum, silicon, titanium and zinc oxides to bacteria (Bacillus subtilis, Escherichia coli and Pseudomonas fluorescens) was examined and compared to that of their respective bulk (micro-scaled) counterparts. All nanoparticles but titanium oxide showed higher toxicity (at 20 mg/L) than their bulk counterparts. Toxicity of released metal ions was differentiated from that of the oxide particles. ZnO was the most toxic among the three nanoparticles, causing 100% mortality to the three tested bacteria. Al(2)O(3) nanoparticles had a mortality rate of 57% to B. subtilis, 36% to E. coli, and 70% to P. fluorescens. SiO(2) nanoparticles killed 40% of B. subtilis, 58% of E. coli, and 70% of P. fluorescens. TEM images showed attachment of nanoparticles to the bacteria, suggesting that the toxicity was affected by bacterial attachment. Bacterial responses to nanoparticles were different from their bulk counterparts; hence nanoparticle toxicity mechanisms need to be studied thoroughly.
authors.affiliation: Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: Hamid
authors.initials: H
authors.lastname: Mashayekhi
authors.forename: Baoshan
authors.initials: B
authors.lastname: Xing
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects*; D004463:Ecology / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000633:toxicity*; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D011551:Pseudomonas fluorescens / Q000187:drug effects*