Real-Time Monitoring of the Cytotoxic Effect of Oxygen-Sensitive Fluorescent Poly(styrene-maleic anhydride) Nanoparticles Using Electrical-Substrate Impedance Sensing

Fluorescent poly(styrene-<i>co</i>-maleic anhydride) (SMA) nanoparticle (NP) oxygen sensors show strong potential for visualizing in situ oxygen gradients in biomedical research. To expand their applications, it is essential to understand their cellular interactions. Electrical cell-substrate impedance sensing (ECIS) enables real-time monitoring of cell behavior by measuring the impedance of monolayer cultures with an alternating current. In this study, we used ECIS to assess the cytotoxicity of SMA NP oxygen sensors and further examined their effects through endothelial barrier function analysis and microscopy. The sensors showed no cytotoxicity at any dose, confirming their biocompatibility. However, the NPs incorporated into the extracellular matrix and may disrupt barrier function. These findings support further use of SMA NP oxygen sensors in biomedical research and highlight ECIS as a valuable tool for evaluating nanoparticle biocompatibility when traditional optical assays are limited by optical interference.