Biological effects of graphene oxide-induced fluorescent marker perturbation in Caenorhabditis elegans via food chain exposure

Graphene oxide (GO), an oxidized derivative of graphene with broad industrial and biomedical applications, has raised increasing concerns about its potential biological risks, although its impacts on human health remain poorly understood. To investigate the biological impacts of GO visualization under conditions simulating food chain exposure, we used Caenorhabditis elegans as the test organism and Nematode Growth Medium (NGM) as the exposure environment to evaluate GO as an environmental pollutant. Our findings demonstrate that this approach effectively facilitates the behavioral endpoints of organisms' emergency responses to environmental stressors, including their effects on the reproductive system, oxidative stress, DNA damage, and other related impacts. Significant apoptosis was observed within the mitotic and meiotic regions of C. elegans gonad under GO stress. Reactive oxygen species (ROS) production and lipofuscin accumulation increased significantly, indicating heightened oxidative stress and cellular damage. In addition, the accumulation of the HSU-1 protein, which may disrupt cellular functions and lead to irreversible DNA damage, was found in gonad cells, further accelerating cell apoptosis in C. elegans. Furthermore, under environmental stress induced by GO, DAF-16::GFP translocates to the nucleus, and SKN-1 protein is overexpressed in the somatic cells of nematodes, triggering an emergency response that effectively mitigates the toxic effects of GO. The toxic effects associated with food chain exposure were significantly greater than those associated with direct exposure. Our study also demonstrated that the toxicological effects associated with GO visualization intensified with increasing GO concentration, with both exposure routes exhibiting dose-dependent characteristics. Moreover, the amplified toxicity of food chain exposure highlights the heightened risks associated with indirect exposure pathways. This study demonstrates the effectiveness of C. elegans as a model organism for visually assessing the biological effects of nanomaterials and environmental pollutants, providing a rapid and efficient method for detecting environmental contaminants.