Assessment of Nanoplastic-Induced Disruption in Cellular Glutathione Metabolism Using a Bubble-Assisted Photothermal Capture SERS Sensor

Nanoplastics (NPs) and their aged counterparts (aNPs) pose growing environmental and health risks; however, their impact on cellular redox homeostasis remains poorly understood due to the difficulty in simultaneously assessing the amounts of cellular glutathione (GSH) and corresponding glutathione disulfide (GSSG) using traditional methods. Here, under NP and aNP postexposure, we introduce a photothermal convective capture SERS strategy to directly assess total glutathione (GSHt) and the GSH/GSSG ratio─critical biomarkers of oxidative stress. This method leverages laser-induced bubble formation on Au nanoisland (AuNIs) substrates to concentrate analytes via convective flow without the need for specific linkers or templates, enabling label-free, one-step detection with high sensitivity. Our results demonstrate that NP exposure dose-dependently depletes GSHt and reduces the GSH/GSSG ratio in cells, indicating exacerbated oxidative damage. Notably, aNPs led to a more pronounced decline in GSHt levels and a faster reduction in the GSH/GSSG ratio than nonaged NPs, with prolonged aging, further amplifying cellular sensitivity. Our findings indicate that aNPs introduce additional oxygenated groups into cells, disrupting key biological processes and highlighting the potential risks associated with NP exposure. In conclusion, this study provides a rapid and direct approach to enhance our understanding of NP toxicity in real-world scenarios.