Effects of TiO2 Nanoparticles on Fish Upper Thermotolerance

Titanium dioxide (TiO2) nanoparticles can be found in a wide variety of products such as sunscreen, soap, and even foods such as Mandamp;Ms. Due to their widespread use, these nanoparticles often find their way to aquatic environments making them a potential threat to aquatic organisms, which has stimulated a surge in research efforts toward understanding the environmental implications of nanotechnology. Our initial objective was to see if TiO2 inhibited fish’s ability to cope with increasing aquatic temperatures as this could present a dual threat when considering the effects of climate change on water temperature. To perform the experiment, we subjected four groups of fish separated into control, saline-injected, polyacrylic acid capsule injected, and TiO2 injected treatments to a critical thermal maximum (CTMax) test and sampled them after loss of equilibrium (LOE). The LOE temperatures for each fish were recorded and an ANOVA test comparing each treatment group to the control group revealed that the TiO2-injected fish demonstrated a significantly reduced thermal maximum compared to control fish. We now seek to find through what mechanisms TiO2 harms fish, and towards that end, we conducted histological analysis of two gill samples from each fish which revealed significantly higher interlamellar cell mass (ILCM) lengths than normal for all treatments, though there was no difference between treatments. We now plan to conduct molecular analysis of the heart, gills, spleen, kidney, and muscle samples to identify if gene expression was altered, and if so, then which genes are affected