title: Biotests and Biosensors for Ecotoxicology of Metal Oxide Nanoparticles: A Minireview.
abstract: Nanotechnologies have become a significant priority worldwide. Several manufactured nanoparticles - particles with one dimension less than 100 nm - are increasingly used in consumer products. At nanosize range, the properties of materials differ substantially from bulk materials of the same composition, mostly due to the increased specific surface area and reactivity, which may lead to increased bioavailability and toxicity. Thus, for the assessment of sustainability of nanotechnologies, hazards of manufactured nanoparticles have to be studied. Despite all the above mentioned, the data on the potential environmental effects of nanoparticles are rare. This mini-review is summarizing the emerging information on different aspects of ecotoxicological hazard of metal oxide nanoparticles, focusing on TiO₂, ZnO and CuO. Various biotests that have been successfully used for evaluation of ecotoxic properties of pollutants to invertebrates, algae and bacteria and now increasingly applied for evaluation of hazard of nanoparticles at different levels of the aquatic food-web are discussed. Knowing the benefits and potential drawbacks of these systems, a suite of tests for evaluation of environmental hazard of nanoparticles is proposed. Special attention is paid to the influence of particle solubility and to recombinant metal-sensing bacteria as powerful tools for quantification of metal bioavailability. Using recombinant metal-specific bacterial biosensors and multitrophic ecotoxicity assays in tandem will create new scientific knowledge on the respective role of ionic species and of particles in toxicity of metal oxide nanoparticles.
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia. anne.kahru@kbfi.ee.
authors.forename: Anne
authors.initials: A
authors.lastname: Kahru
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.|Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia.
authors.forename: Henri-Charles
authors.initials: HC
authors.lastname: Dubourguier
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
authors.forename: Irina
authors.initials: I
authors.lastname: Blinova
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
authors.forename: Angela
authors.initials: A
authors.lastname: Ivask
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
authors.forename: Kaja
authors.initials: K
authors.lastname: Kasemets
keywords: 3Rs; Aquatic toxicity; Bioavailability; CuO; Daphnia magna; Pseudokirchneriella subcapitata (Selenastrum capricornutum); Recombinant sensor bacteria; Tetrahymena thermophila; Thamnocephalus platyurus; TiO2; Vibrio fischeri; ZnO