Institute for Cardiovascular Research, VU University Medical Center 1 article published in JoVE Bioengineering Electric Cell-substrate Impedance Sensing for the Quantification of Endothelial Proliferation, Barrier Function, and Motility Robert Szulcek1, Harm Jan Bogaard1, Geerten P. van Nieuw Amerongen2 1Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, 2Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center This protocol reviews Electric Cell-substrate Impedance Sensing, a method to record and analyze the impedance spectrum of adherent cells for the quantification of cell attachment, proliferation, motility, and cellular responses to pharmacological and toxic stimuli. Detection of endothelial permeability and assessment of cell-cell and cell-substrate contacts are emphasized.