PEDOT:PSS OECTs as versatile devices for real-time monitoring of cytotoxicity and viral infection

Semiconducting polymers are promising materials for biomedical application due to their ability to conduct both ions and electrons, their biocompatibility and their flexible and soft mechanical nature. In particular, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has high conductivity and reversible electrochemical properties in acqueous environment making it suitable as smart biointerfaces with biological entities. We present PEDOT:PSS-based Organic Electrochemical Transistors (OECTs) for the electrical continuous monitoring of cell viability, providing fast and real-time outputs which overcome standard optical-based techniques, without the need of toxic substance staining or highly-specialized operators. Cells are directly grown on transparent, PEDOT:PSS-based thin film OECTs: the presence of a cell monolayer slows down ion flux from the electrolyte into the semiconducting polymer, allowing for an electronic readout of cell layer health. We demonstrated that the devices can evaluate in real-time cytotoxicity of external agents, viral infection pathway and titration on cells. Moreover, testing Sars-Cov-2 infected cells, we observed that OECTs can automatically quantifying neutralizing antibodies in human sera in less than 48h. PEDOT:PSS OECTs provide a scalable, low-cost and versatile biosensor for monitoring cell culture stress response, paving the way for high throughput drug discovery screening, toxicology evaluations, and serum neutralization assays.