Real-time quantification of nanoplastics-induced oxidative stress in stretching alveolar cells

Nanoplastics from air pollutants can be directly inhaled into the alveoli in the lungs and further enter blood circulation, and numerous studies have revealed the close relation between internalized nanoplastics with many physiological disorders via intracellular oxidative stress. However, the dynamic process of nanoplastics-induced oxidative stress in lung cells under breath-mimicked conditions is still unclear, due to the lack of methods that can reproduce the mechanical stretching of the alveolar and simultaneously monitor the oxidative stress response. Here, we describe a biomimetic platform by culturing alveoli epithelial cells on a stretchable electrochemical sensor and integrating them into a microfluidic device. This allows reproducing the respiration of alveoli by cyclic stretching of the alveoli epithelial cells and monitoring the nanoplastics-induced oxidative stress by the built-in sensor. By this device, we prove that cyclic stretches can greatly enhance the cellular uptake of nanoplastics with the dependencies of strain amplitude. Importantly, oxidative stress evoked by internalized nanoplastics can be quantitatively monitored in real time. This work will promote the deep understanding about the cytotoxicity of inhaled nanoplastics in the pulmonary mechanical microenvironment.