PiN Faculty Member - Adam Cohen, PhD

Adam Cohen, PhD

Professor of Chemistry and Chemical Biology and Physics
Howard Hughes Medical Institute Investigator

Harvard University
Depts. of Chemistry and Chemical Biology and of Physics
12 Oxford Street
Cambridge, MA 02138
Tel: 617-496-9466
Visit my lab page here.

The Cohen Lab develops new physical tools to study molecules, cells, and organisms. We combine spectroscopy, protein engineering, nanofabrication, microscopy, and computation to find new ways to visualize the inner workings of biological systems. Recent work in the lab has focused on developing genetically encoded fluorescent reporters of membrane voltage, and the optical instrumentation to map membrane voltage with high resolution in space, time, and voltage.

Every cell is encased in an electrically insulating lipid membrane, bathed in a conducting milieu. The membrane can support an internal electric field, which tugs on charges in the membrane. Membrane voltage modulates the free-energy landscape of all molecules associated with the membrane. This voltage regulates the activity of neurons, cardiac cells, and many other biological structures. A key challenge has been the difficulty of visualizing changes in transmembrane potential. We discovered that a protein derived from a Dead Sea microorganism could function as an exquisitely fast and sensitive fluorescent reporter of membrane voltage. By engineering the photocycles of microbial rhodopsins, we developed fluorescent voltage indicators which could implement new measurement modalities, such as light-gated voltage integration, and measurements of absolute voltage.

We have used all-optical electrophysiology to study neural function in primary neurons in vitro, in human iPSC-derived neurons, in acute brain slice, and in live mice. Measurements in intact tissue pose interesting technical challenges associated with kilohertz-rate imaging through a strongly scattering, autofluorescent medium. Optical electrophysiology in neurons provides insights into diseases such as pain, epilepsy, and ALS.

Last Update: 3/30/2017


For a complete listing of publications click here.



© 2016 President and Fellows
of Harvard College