From Nanoplastics to Microplastics: Cellular and Whole Animal Dynamics and Interaction in a Model Fish System

Plastic-related products have been involved in almost every aspect of our lives. Massive plastic wastes owing to the lack of regulation and oversight present one of today’s most pressing global environmental issues. Microplastics (MPs) and nanoplastics (NPs) have attracted extensive attention since they are relatively easily ingested, accumulated, and further transferred along food chains, potentially becoming hazardous to humans. Several key parameters have been identified to play vital roles in the toxicity of MPs/NPs, including their type, size, shape, and surface chemistry (functional groups and charge). There are now arguments that NPs should not be regarded as counterparts of MPs given their differential behavior. Despite the many studies on the cellular and animal systems, there are still pressing questions such as the 1) rates and routes at which these nano/microplastics enter and leave the biological systems, 2) their traveling (trafficking) in cellular and whole animal systems as well as the factors controlling their trafficking and transformations, and 3) identification of sensitive subcellular biomarkers linking with plastics bioaccumulation. Novel technologies coupled with classical ecotoxicological theories are indispensable in addressing these key questions. In this project, I propose to develop novel bioimaging techniques to study the dynamics and interaction of micro/nanoplastics with fish systems, both in vivo (whole animal system) andin vitro/ex vivo(cell system). We will synthesize aggregated induced emission (AIE) based fluorescent nano/microplastics of different sizes, charges and surface properties, displaying excellent photostability and biocompatibility. With these novel bioprobes, we will 1) study the cellular biokinetics of NPs and correlate these with cellular toxicity; 2) study the intracellular trafficking of NPs and target organelles; and 3) study the dynamics of MPs in zebrafish and underlying toxic mechanisms. With the application of our novel technique, we will actually quantify the rates and routes at which these nanoplastics are accumulated by the zebrafish cells and whole animals. The bioaccumulation potentials of nano/microplastics will be compared among different physico-chemical properties using a standardized cell line or fish system. Such information is most needed in the real environmental assessments of these plastics in the environment. We will also reveal the trafficking of these plastics across different subcellular compartments or fish tissues, as well as the cellular/animal machinery responses to these plastics. Overall, our project should provide critical knowledge on the dynamics and interactions of nano/microplastics of different natures with fish models, with a wide application in environmental regulation.