Friedrich-Alexander-Universitat (FAU) Erlangen-Nurnberg and Universitatsklinikum Erlangen 1 article published in JoVE Medicine Investigating Intestinal Barrier Breakdown in Living Organoids Marco Bardenbacher1, Barbara Ruder2, Natalie Britzen-Laurent1, Elisabeth Naschberger1, Christoph Becker2, Ralph Palmisano3, Michael Stürzl*1, Philipp Tripal*1,3 1Division of Molecular and Experimental Surgery, Department of Surgery, Translational Research Center, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, 2Department of Medicine 1, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, 3Optical Imaging Centre Erlangen (OICE), Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg Here we describe a technique to quantify the barrier integrity of small intestinal organoids. The fact that the method is based on living organoids enables the sequential investigation of different barrier integrity modulating substances or combinations thereof in a time-resolved manner.