Using animal cells as sensors for xenobiotics: Monitoring phenotypic changes by multimodal impedance assays

Cell-based assays are valuable in vitro tools to screen for the impact of environmental pollutants on human health. Fostered by the recent progress on induced pluripotent stem cells, the collection of in vitro models for human tissues is continuously increasing. Noninvasive, label-free readout approaches to monitor cell-based assays, in particular those that are based on electrochemical impedance measurements, have paved the way to a time-resolved observation of various phenotypic assays that report on changes in cell spreading, migration, proliferation, or differentiation upon exposure to xenobiotics. This review summarizes the state of the art. It stresses the need for a more in-depth analysis of biological harm that goes beyond simple cytotoxicity testing.