Human Sweat-Mediated Aggregation of Nanoplastics as a Driver of Dermal Exposure

The study investigates how human sweat influences the aggregation of polyethylene nanoplastics (PENPs), which affects their dermal exposure risks. Key factors affecting aggregation include nanoplastic concentration (49.8%), photoaging (17.1%), and organic constituents like l-histidine (8.7%). Higher PENP concentrations promote aggregation, reducing penetration through sweat glands and hair follicles, while photoaging increases penetration potential. L-histidine enhances dispersion and penetration of PENPs but promotes aggregation of photoaged PENPs, reducing their penetration. The study predicts higher penetration risks in females, overweight individuals, and certain populations due to factors like lower particle concentration and stronger photoaging. These findings enhance understanding of PENP exposure and associated health risks.