Max-Planck Institute for Immunobiology und Epigenetics 1 article published in JoVE Biology LED Thermo Flow — Combining Optogenetics with Flow Cytometry Kathrin Brenker1,2,3, Kerstin Osthof1,4, Jianying Yang1,3, Michael Reth1,3,5 1Max-Planck Institute for Immunobiology und Epigenetics, 2Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 3Centre for Biological Signaling Studies, BIOSS, University of Freiburg, 4Albert-Ludwigs-Universität, 5Institute for Biology III (Mol. Immunology), Albert-Ludwigs-Universität Optically controlled substances are powerful tools to study signaling pathways. To expand the spectrum of possible experiments, we developed a device for studying optically controlled substances in real time using flow cytometry: the LED Thermo Flow.