title: Assessing the effect of different natural dissolved organic matters on the cytotoxicity of titanium dioxide nanoparticles with bacteria.
abstract: Titanium dioxide nanoparticles (TiO2NPs) are among the most widely manufactured nanomaterials on a global scale. However, prudent and vigilant surveillance, incumbent upon the scientific community with the advent of new technologies, has revealed potentially undesirable effects of TiO2NPs on biological systems and the natural environment during their application and discharge. Such effects are likely best evaluated by first assessing the fate of the TiO2NPs in natural environments. In this study, the effects of terrestrial humic acid (HA) and tannic acid (TA), two major members of the collective: dissolved organic matter (DOM), on the cytotoxicity of TiO2NPs to Escherichia coli were investigated in the presence and absence of natural sunlight. Qualitative (transmission electron microscopy (TEM)) and quantitative (LC50) analyses were employed in this study. In addition, the production of reactive oxygen species (ROS) in the form of OH was further assessed-as HA or TA increased the production of ROS decreased. The inhibition of bacterial viability in the light treatment groups, with respective treatment organics at concentrations of 10 ppm, was less in TA than in terrestrial HA. SAS was used to analyze the treatment effect of individual factors of light irradiation, DOM, and concentration of TiO2NPs.
authors.affiliation: Department of Biology, Jackson State University, Jackson, MS 39217, USA. Electronic address: xiaojia.he25@uga.edu.
authors.forename: Xiaojia
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Biology, Jackson State University, Jackson, MS 39217, USA.
authors.forename: Donee'
authors.initials: D
authors.lastname: McAlliser
authors.affiliation: Environmental Science Ph.D. Program, Jackson State University, Jackson, MS 39217, USA.
authors.forename: Winfred G
authors.initials: WG
authors.lastname: Aker
authors.affiliation: Department of Biology, Jackson State University, Jackson, MS 39217, USA.
authors.forename: Huey-Min
authors.initials: HM
authors.lastname: Hwang
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D004785:Environmental Pollutants / Q000737:chemistry / Q000633:toxicity*; D006812:Humic Substances; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D046529:Microscopy, Electron, Transmission; D017382:Reactive Oxygen Species; D013472:Sunlight; D013634:Tannins / Q000737:chemistry; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*
chemical_list: D004785:Environmental Pollutants; D006812:Humic Substances; D017382:Reactive Oxygen Species; D013634:Tannins; C009495:titanium dioxide; D014025:Titanium
keywords: Cytotoxicity; Humic acid; ROS; Tannic acid; TiO(2) nanoparticles