Cohen Lab

Physical tools to study molecules, cells, and organisms

We invent new physical tools to probe biological structures. We use our tools to make new measurements. We choose problems by looking in unexplored regimes of time and space. We combine protein engineering, lasers, nanofabrication, microfluidics, electronics, biochemistry, and computers to generate data; and we apply statistics and physical modeling to understand the data.


Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

Optically triggered action potential in a rat hippocampal neuron, mapped at 100,000 frames/s.


Research Areas


Previous projects

Optical chirality, trapping single molecules, microbial and molecular motion in mucus, nonequilibrium van der Waals forces, DNA mechanics, spectral shift FRET, science education in Liberia.



DNA Pulley (9/2015)

Min Ju developed a nanofabricated pulley to profile the locations of proteins bound to DNA. It's like feeling beads on a string. Read about it in Nucleic Acids Research!

2PAC LIVS (9/2015)

Daan evaluated the prospects for 2-photon voltage imaging using genetically encoded voltage indicators. He invented 2P absolute contrast lifetime image voltage sensing (2PAC LIVS). Read about it in Biophysical Journal!

Welcome to Liz Wood (6/2015)

Liz Wood joins the lab after a postdoc in Denmark and a PhD at MIT. Liz will be exploring unusual physical phenomena in living organisms.

Welcome summer undergrads (6/2015)

Eli Weinstein, Elaine Reichert, Jeong Jun (JJ) Kim, Alexander Su, and William Bloxham will be working on all sorts of wild projects. It will be a fun summer!

Rhodopsin patent issued (6/2015)

The first patent on using microbial rhodopsins for voltage imaging just issued from the USPTO. It's patent 9,057,734.

Miao receives LSRF fellowship (6/2015)

Congratulations to Miao on receiving three years of full support from the Life Sciences Research Foundation. This will support her work on optical patterning, selection, and assembly of cellular structures.

A pair of fine Fellows (2/2015)

Congratulations to Daniel on being admitted into the Harvard Society of Fellows! Congratulations to Miao on being a finalist for the LSRF competition!

Will you be mine? (1/2015)

Miao invented a technique to optically select single cells from culture! She photochemically immobilizes the cell on the coverslips. Her paper just came out in Chemical Science. Congratulations, Miao!

Optogenetics with simultaneous imaging of GFP reporters (10/2014)

Veena just published a paper showing how to independently control a blue light-activated channelrhodopsin while simultaneously measuring GFP-based reporters-without optical crosstalk. The trick? Multiwavelength nonlinear control of "stoplight" channelrhodpsins. A fitting finish for a fantastic PhD.

Rub your hands together and do the twist (9/2014)

Dian's paper on chirality-dependent solid-solid friction just came out in Langmuir. He showed that for molecular solids rubbing against each other, the friction force depends on the relative chirality, a consequence of chirality-dependent non-covalent interactions between the molecules on the surfaces. Congratulations, Dian!

CaViar in fish (9/2014)

Jen's paper on simultaneous voltage and calcium imaging throughout development of the embryonic zebrafish heart just came out! The CaViar reporter combines a gCaMP-based calcium indicator and an Arch-based voltage indicator. The supplementary movies will make your heart go pitter-patter.

eFRET GEVIs make a flashing rainbow (8/2014)

Peng and Yongxin's paper describes a new approach to voltage imaging: they use voltage-dependent fluorescence resonance energy transfer (electrochromic FRET) from a fluorescent protein to a microbial rhodopsin to make multicolored genetically encoded voltage indicators (GEVIs). Now we can light up neurons in technicolor!

Pleasant Surprises (8/2014)

Adam won three nice prizes: The Blavatnik Award for Young Scientists, an NIBIB Nagy New Investigator award, and the Pure Chemistry award from the American Chemical Society. Special thanks to the many students and postdocs whose hard work these awards recognize!

All-optical electrophysiology (6/2014)

Congratulations to Daniel, Yongxin, and the whole team for their major paper on all-optical electrophysiology, published in Nature Methods.  Watch supplementary movies 4 - 6 to  make your neurons light up!

Bringing Bioelectricity to Light (6/2014)

Veena and Adam wrote a review in Annual Reviews of Biophysics describing how one should think about electrophysiology measurements when the actuators and reporters are transmembrane proteins rather than physical electrodes.  Bioelectric phenomena are wondrous and varied!

Weintraub Award to Daniel Hochbaum (2/2014)

Daniel Hochbaum has been awarded the Harold M. Weintraub Graduate Student Award for outstanding achievement during graduate studies in the biological sciences.  Not bad for a physicist!

Absolute Voltage (2/2014)

Jen and Veena discovered how to measure absolute membrane voltage via rhodopsin photocycle dynamics.  Read about it in Biophysical Journal.  See also a nice commentary from John Spudich.  Cheers to Jen and Veena!

A flash of memory! (1/2014)

Veena and Daan's paper on Flash Memory came out in JACS.  They showed how one could store a long-lasting photochemical imprint of neuronal activity in a microbial rhodopsin. This suggests a path to whole-brain neural recording, though there's still a lot of work to do.

Spiking HEKs (1/2014)

We made a line of non-fluorescent HEK cells that produce spontaneous electrical spikes in confluent culture.  They produce beautiful waves and spiral patters of electrical activity.  Shocking!  These are great for testing prospective fluorescent voltage indicators.  The paper is in PLoS One. Congratulations Jeehae and Kit!



©2015 Adam E. Cohen