Cohen Lab

Building new tools to study biomolecules

Our effort is split between developing new physical tools to probe biological molecules, and using our tools to make new measurements. We choose problems by looking in unexplored regimes of time and space; we combine nanofabrication, lasers, microfluidics, electronics, biochemistry, and computers to generate data; and we apply statistics and physical modeling to understand the data.

Research Areas


Trapping Single Molecules	Control of Molecules with Sculpted Electromagnetic Fields

Microbial and Molecular Motion in Mucus	Spectral Shift FRET to Probe Photoactive Proteins

Dynamics of DNA	Nanoparticles in Arbitrary Force Fields

Nonequilibrium van der Waals Forces	Science Education in Liberia

Previous projects

Biological solitons, twisting instability in fibrillar nanomaterials, carbon nanotube electronics at low temperature and high magnetic field, Langmuir-Blodgett monolayers of magnetic nanocrystals, redox cycling in self-assembled molecular junctions, Mesoamerican archaeoastronomy, feedback-induced oscillations in the Tiger Salamander eye, iterated complex polynomials and fractals, electrochemical detection of TNT, homebuilt STM, computer control with eye movements.

News

Nanomagnetic control of intersystem crossing (9/3/09)

Adam wrote a theoretical paper showing how magnetic nanostructures can enhance the rate of intersystem crossing in spin-correlated radical pairs, published in J. Phys. Chem. A. The point is that nanoscale magnetic fields can affect chemistry in ways that macroscale fields can't.

Spectroscopy in sculpted fields (6/31/09)

Nan, Yiqiao, and Adam wrote a paper on spectroscopy in sculpted fields, published in Nano Today. The premise is that molecules do interesting tricks when exposed to electromagnetic fields that vary significantly over the extent of a single molecule.

Launch of The Liberian Scientist (7/31/09)

Gillie's website, The Liberian Scientist, has gone live. This online journal provides a forum to publish scientific research originating in Liberia, as well as articles about science education in Liberia. Please have a look! See also this article in The Liberian Times and this one in The Daily Observer.

Gillie and Binny depart (7/31/09)

Gillie Collins and Binny Cherayil have returned to their academic home institutions (Hunter College High School, and the Indian Institute of Science, respectively). Thanks to both for a great summer! See some action shots of the going away party.

DARPA Young Faculty Award (7/9/09)

Adam was awarded a DARPA Young Faculty Award to work on magnetic field effects in chemical reactions. Hooray! Magnetic field effects in chemistry are a beautiful example of room temperature quantum coherence.

Teaching Science in Liberia (6/22/09)

Adam spent two weeks teaching science in cities and towns in Liberia. A brief trip report and plans for future work are given here.

I Spy a Postdoc (5/25/09)

We were awarded an Intelligence Community Postdoctoral Fellowship to develop new approaches to bioimaging. Great news!

No FDCD in single helicenes (5/13/09)

Yiqiao and Tim Cook tried to replicate reports of fluorescence detected circular dichroism in single helicene molecules. We found good evidence that the earlier signals were an artifact. So we wrote a paper, and it just got published. Here is a comment from the authors of the original paper, and our comment on their comment.

Welcome Binny Cherayil (4/28/09)

Binny comes from the Indian Institute of Science in Bangalore. He will be spending the summer working on the theory of chemically propelled nanostructures. Welcome Binny!

ONR YIP (3/20/09)

Adam was awarded the Young Investigator Prize from the Office of Naval Research. This will support research on "Molecular Spintronics: Nanomagnetic Control of Electronic Spins." Hooray!!

Asumana Randolph Speaks on Teaching Science In Liberia (3/16/09)

Asumana Randolph visited from Hunter College High School and gave an impassioned talk about his work teaching science in Liberia, and the iHelp Liberia Project. Here are some photos of his visit.