Adsorption of Cd to TiO₂-NPs Forms Low Genotoxic Aggregates in Zebrafish Cells

Abstract

The aquatic environment is involved in the pollutants spreading mechanisms, including nanomaterials and heavy metals. The aims of this study were to assess the in vivo genotoxicity of Cd (1 mg/L) and to investigate the genomic effects generated by its co-exposure with TiO2-NPs (10 µg/L). The study was performed using zebrafish as a model for 5, 7, 14, 21, and 28 days of exposure. The genotoxic potential was assessed by three experimental approaches: DNA integrity, degree of apoptosis, and molecular alterations at the genomic level by genomic template stability (% GTS) calculation. Results showed an increased in DNA damage after Cd exposure with a decrease in % GTS. The co-exposure (TiO2-NPs + Cd) induced a no statistically significant loss of DNA integrity, a reduction of the apoptotic cell percentage and the recovery of genome stability for prolonged exposure days. Characterization and analytical determinations data showed Cd adsorption to TiO2-NPs, which reduced free TiO2-NPs levels. The results of our study suggest that TiO2-NPs could be used for the development of controlled heavy metal bioremediation systems.

Keywords

• DNA damage
• apoptotic cells
• genome instability
• titanium dioxide nanoparticles
• cadmium
• zebrafish