Effects of TiO2 nanoparticles on ROS production and growth inhibition using freshwater green algae pre-exposed to UV irradiation

Environ Toxicol Pharmacol. 2015 May;39(3):1074-80. doi: 10.1016/j.etap.2015.03.015. Epub 2015 Apr 1.

Abstract

This study investigated the possibility that titanium dioxide nanoparticles (nano-TiO2) toxicity in Pseudokirchneriella subcapitata involves reactive oxygen species (ROS) production, using the dichlorodihydrofluorescein (DCF) assay. Algae were exposed to nano-TiO2 under laboratory fluorescent lamps supplemented with UV irradiation for 3h, with or without a UV filter. Results showed that nano-TiO2 increased ROS production in UV-exposed cells, with or without a UV filter (LOEC values were 250 and 10mg/L, respectively). Sublethal effects of nano-TiO2 on UV pre-exposed algae were also examined. Toxicity studies indicated that exposure to nano-TiO2 agglomerates decreased algal growth following 3h pre-exposure to UV, with or without a UV filter (EC50s were 8.7 and 6.3mg/L, respectively). The present study suggests that the growth inhibitory effects of nano-TiO2 in algae occurred at concentrations lower than those that can elevate DCF fluorescence, and that ROS generation is not directly involved with the sublethal effects of nano-TiO2 in algae.

Keywords: Pseudokirchneriella subcapitata; Reactive oxygen species (ROS); TiO(2) nanoparticle; Toxicity mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chlorophyta / drug effects
  • Chlorophyta / growth & development*
  • Chlorophyta / radiation effects
  • Dose-Response Relationship, Drug
  • Fresh Water
  • Metal Nanoparticles / toxicity*
  • Reactive Oxygen Species / metabolism*
  • Titanium / toxicity*

Substances

  • Reactive Oxygen Species
  • titanium dioxide
  • Titanium