State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China.
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, P. R. China.
Environ Sci Technol. 2023 Apr 25;57(16):6626-6635. doi: 10.1021/acs.est.2c07537. Epub 2023 Apr 12.
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 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.
纳米塑料（NPs）因其潜在的健康影响而引起了全球关注。在此，经过模拟和自然太阳辐射后，发现聚乙烯、聚丙烯、聚苯乙烯和聚氯乙烯纳米塑料（PVC NPs）表现出增强的荧光，特别是 PVC NPs。此外，通过将一种模式水生生物暴露于这些 NPs 来评估光老化 NPs 作为潜在荧光指示剂的作用。我们的结果表明，由于共轭π键的生成，光老化 NPs 表现出强荧光，这可以实现低能量消耗的π-π*电子跃迁。光致荧光还使光老化 NPs 能够作为高效荧光示踪剂，有助于跟踪 NP 在各种生物体中的迁移。双光子激光共焦扫描显微镜的结果表明，光老化 NPs 可以穿过生物屏障，并在摄入和排泄之外积累在肠道外组织中。此外，与原始 NPs 相比，光老化 NPs 更容易发生生物降解，这可能是由于光致含氧基团的增加导致亲水性增强所致。因此，除了生产不附着外部荧光染料的荧光 NPs 外，自然光老化过程可以促进食物链中光老化 NPs 的迁移和降解。
