Study of the ecotoxicity of gold nanoparticles in marine ecosystems with <em>Aliivibrio fischeri</em> (ES114) and <em>Symbiodinium microadriaticum</em> as model organisms

Abstract

As the frontier of nanotechnology expands, it reshapes materials science with innovative synthesis and characterization techniques that promise far-reaching applications. Despite their rapid proliferation in various ecosystems, the environmental impacts of nanomaterials are frequently overlooked. Nanomaterials are not regularly tracked and have been identified as emerging pollutants due to their potential to cause adverse ecological and human health effects. Special interest has arisen in marine ecosystem assessments of environmental risk due to the vulnerability and recent biodiversity loss from climate change and pollution. <em>Aliivibrio fischeri</em> and <em>Symbiodinium microadriaticum</em> are studied together to have a coerced understanding of the ecotoxicity of gold nanoparticles in marine ecosystems. This thesis explored the development of environmentally sustainable gold nanoparticles using algal biopolymers as stabilizing agents and introduces a comprehensive methodological framework combining traditional toxicity tests and untargeted metabolomics for assessing the ecotoxicity of these nanoparticles in marine environments, thereby providing critical insights into minimizing their ecological impact. Surface modification of gold nanoparticles with biopolymers such as peptides and polysaccharides seems to improve the material's stability overall. The antioxidant capacity of the peptide-stabilized gold nanoparticles was enhanced while the bacterial test demonstrated decreased toxicity for the nanoparticles. The algal polysaccharides negatively affected the antioxidant capacity of the gold nanoparticles. This diminishing of the antioxidant capacity of the polysaccharide-modified gold nanoparticles is consistent with the increased toxicity observed with the bacterial model. However, gold nanoparticles affected all the metabolic parameters tested for both model organisms compared to the control groups.