Aged Biodegradable Nanoplastics Enhance Body Accumulation Associated with Worse Neuronal Damage in <i>Caenorhabditis elegans</i>

The environmental and health challenges posed by petroleum-based biodegradable plastics, such as polybutylene succinate (PBS) and polybutyleneadipate-co-terephthalate (PBAT), are a significant concern because they are increasingly present in the environment and contribute a substantial proportion of microplastics (MPs) or nanoplastics (NPs). In this study, ultraviolet (UV)-aged PBS-NPs and PBAT-NPs are found to have a higher propensity to accumulate within the body of <i>Caenorhabditis elegans</i> (<i>C. elegans</i>) by prolonging the defecation interval, which could induce severe neuronal damage compared to pristine NPs. The increased accumulation of biodegradable nanoplastics (BNPs) and subsequent impairments of neurobehavior are highly attributed to their reduced particle size and altered surface properties, including changed chemical bonds and functional groups after photoaging. Aged BNPs also cause more severe damage to GABAergic neurons and neurotransmitter receptors, resulting in disrupted neuronal homeostasis and behaviors. Overall, BNPs of both PBS and PBAT components show no significant differences in biological accumulation and mechanisms of neural damage, highlighting the commonalities and characteristics of the adverse effects of petroleum-based BNPs on the nervous system. Our study opens up the exploration of the health impacts of photoaging and the degradation state of BNPs that are increasingly present in the environment.