Nanoplastics (NPs) have raised global concern owing to their potential health effects. Herein, after simulated and natural solar irradiation, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride) nanoplastics (PVC NPs) were observed to exhibit enhanced fluorescence, particularly PVC NPs. Furthermore, the role of photoaged NPs as a potential fluorescence indicator was evaluated by exposing a model aquatic organism Daphnia magna to these NPs. Our results revealed that photoaged NPs exhibited strong fluorescence owing to the generation of conjugated π bonds, which can achieve π-π* electron transition with low energy consumption. Photogenerated fluorescence also enabled the photoaged NPs to act as efficient fluorescent tracers, which can help track NP migration in various organisms. The results of two-photon laser confocal scanning microscopy revealed that the photoaged NPs could translocate across biological barriers and accumulate in extraintestinal tissues in addition to being ingested and excreted. Moreover, compared with pristine NPs, the photoaged NPs underwent biodegradation more easily, probably because of increased hydrophilicity due to photogenerated oxygen-containing moieties. Therefore, in addition to producing fluorescent NPs without the attachment of external fluorescent dyes, the natural photoaging process can promote the migration and degradation of photoaged NPs in food chains.
Bibliographical noteFunding Information:
This work was financially supported by the National Natural Science Foundation of China (22176092, 22276091, and 22241601), Fundamental Research Funds for the Central Universities (2022300311 and 0211/14380174), the Excellent Research Program of Nanjing University (ZYJH005) and the International Institute for Environmental Studies. We thank the Analytical Center and High Performance Computing Center of Nanjing University for the characterization of samples and the computational study.
© 2023 American Chemical Society.
- aquatic creatures
- fluorescent tracer
- natural photoaging
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry