Differential Effect of Solar Light in Increasing the Toxicity of Silver and Titanium Dioxide Nanoparticles to a Fish Cell Line and Zebrafish Embryos

Abstract

The increasing use of silver (Ag) and titanium dioxide (TiO2) nanoparticles (NPs) in consumer products and their inevitable seepage into the environment prompted us to investigate their potential toxicity to a fish cell line (BF-2) and zebrafish embryos under dark and Simulated Solar Light (SSL) exposure conditions. Using high throughput screening (HTS) platforms, we showed that the oxidative stress-dependent cytotoxicity and embryonic toxicity of NPs were significantly increased upon exposure to SSL. While, the toxicity of TiO2 NPs under SSL exposure could be explained by hydroxyl radical generation, the enhanced toxicity of Ag NPs under SSL exposure was due to surface oxidation and physicochemical modification of Ag NPs and shedding of Ag+, leading to an increased bioavailability of silver. Our observations that solar light could induce physicochemical transformation of TiO2 and Ag NPs and enhance their toxic potential emphasizes the need for conducting future toxicity studies under environmentally relevant exposure conditions to guide decision making on the safe handling of NPs.

Predicting the environmental impact of nanosilver

“…Other studies that addressed the behavior of AgNPs in natural waters in the presence and absence of humic materials and other organic solutes showed condition-and coating-dependent agglomeration or stabilization of AgNPs (Chappell et al, 2011;Li and Lenhart, 2012;Piccapietra et al, 2012). Moreover, two recent studies reported that AgNPs can be regenerated through sunlightdriven reduction of Ag + by organic matter (Hou et al, 2013;Yu et al, 2014), whereas George et al (2014) reported that solar light increased AgNP dissolution and thus its toxicity to a fish cell line and zebrafish embryos further emphasizing the importance of environmental factors in determining the fate of AgNPs.…”

Effect of natural and synthetic surface coatings on the toxicity of multiwalled carbon nanotubes toward green algae

“…0-30 mg/L MWCNTs with 5 mg/L DOM and 10 mg/L MWCNTs with 0-10 mg/L DOM. The last group was to measure the potential contribution of oxidative damage to the algal toxicity of MWCNTs (15 mg/L) as affected by the three DOMs (5 mg/L) in the absence and presence of 0.5 mM N-acetyl cysteine (NAC) (Sigma, USA) which was used as a ROS scavenger [34].…”

Sequential assessment via daphnia and zebrafish for systematic toxicity screening of heterogeneous substances

“…To evaluate the combined toxicities of mixtures with various combination of UV-filters rather than a single UV-filter, two different types of UV-filters, ethylhexyl methoxycinnamate (EHMC) (UVA protection) (Christen et al, 2011;Kaiser et al, 2012a;Sieratowicz et al, 2011) and Benzophenone-3 (BP-3) (UVB protection) Sieratowicz et al, 2011), were chosen based on their toxicities to aquatic organisms. To better understand the interaction between toxic-and non-toxic substances in a mixture, titanium dioxide nanoparticles (TiO 2 NPs) was also chosen in this study, due to the reports that there was no noticeable toxicity of TiO 2 NPs (George et al, 2014;Marcone et al, 2012;Pavagadhi et al, 2014;Strigul et al, 2009;Zhang et al, 2012;Zhu et al, 2010) to aquatic organisms such as Vibrio fischeri, Daphnia magna, and zebrafish embryo (approximately up to 10 mg/L).…”