Cohen Lab

News Archive


Welcome to Xin and Yoav (12/2013)

Two new postdocs joined the lab.  Yoav comes from the lab of Adi Mizrahi at Hebrew U.  Yoav will be looking at optical electrophysiology in mouse brains.  Xin Tang comes from the lab of Taher Saif at UIUC.  Xin will study bioelectric and biomechanical effects outside the nervous system.  Welcome both!

Doctor! Doctor! (10/2013)

Congratulations to Jen and Min Ju for defending their PhD theses! Jen's topic was "Dynamics in Biological Soft Materials," and Min Ju's was "Trapping and Manipulating Single Molecules of DNA". We will miss you both! 

New faces in lab (9/2013)

Jonathan Gootenberg joins as a rotation student, continuing the proud tradition of our lab importing our brains from MIT.  Miao-Ping Chien joins as a postdoc from UCSD.  Miao-Ping comes from Nathan Gianneschi's Lab at UCSD, where she worked on stimulus-responsive nanomaterials and drug delivery.  Here she'll be helping us see what we feel.  Shan Lou joins as a postdoc from Qiufu Ma's lab at the Dana Farber Cancer Institute, where she worked on the sense of touch.  Here she will be imaging electrical activity in peripheral nerves.  Welcome all!

Check out our kinky genes! (8/2013)

Alex's paper on Euler buckling and nonlinear kinging in double-stranded DNA was just published in Nucleic Acids Research. Nice work, Alex!

Adam appointed HHMI Investigator (5/2013)

The Howard Hughes Medical Institute selected Adam as one of its new investigators. Thank you Mr. Hughes!

Alex defends thesis (5/2013)

Alex passed his thesis defense with an elegant discussion of the ABEL trap, and also recent work on DNA mechanics. Congratulations Dr. Fields!

Welcome to Vedha Nathan (5/2013)

Vedha Nathan is joining the lab as a Research Assistant. She comes with many years of experience working in Howard Berg's lab. Welcome Vedha!

Arch photophysics (3/2013)

Archaerhodopsin 3 (Arch) acts as a fluorescent reporter of membrane voltage. But how does it work? Dougal, Veena, and Hohjai elucidate the mechanism in PNAS.

Twisty nanowires (1/2013)

Yiqiao's paper on chiroptical effects in twisted nanowire plasmonic oscillators came out in Applied Physics Letter. A nice twist to finish your thesis.

Welcome Maggie! Thank you Jeff! (1/2013)

Maggie Kenar is taking over the administrative management of the lab from Jeff Fosdick. Thank you for all your help Jeff, and welcome to the family, Maggie.

Doctor, Doctor! (12/2012)

Congratulations to Yiqiao and Nan for successfully defending their PhD theses. First two students to graduate from the group. Nice work, guys!!

Popular Scientist (10/2012)

Adam features in this month's issue of Popular Science as one of their "Brilliant 10". I never won a popularity contest before!

Optimal tracking of a Brownian particle (9/2012)

Congratulations to Alex on his recent paper in Optics Express! The paper explains the theory of how to do as good a job as possible tracking a dim, quickly diffusing object.

Nice dimples -- paper in JACS (8/2012)

Min Ju's paper on trapping single molecules in nanoscale dimples will appear as an article in JACS. Nice work Min Ju!

New affiliations (6/2012)

Our lab is now part of the Harvard Stem Cell Institute, and the Harvard Center for Brain Science. Cloned brains, coming right up!

Changing of the Lab Tech guard (6/2012)

Lucy Rosenbaum finished her time as a lab tech and will be starting med school next year. We'll miss you Lucy! Tony Shen started in this job. Welcome Tony!

New postdocs join lab (6/2012)

Welcome to Kit Werley and Daan Brinks. Kit did his PhD with Keith Nelson at MIT. Kit will be working on improved voltage indicators. Daan did his PhD with Niek van Hulst at ICFO in Barcelona. Daan will work on nonlinear optics approaches to voltage imaging. Welcome Kit and Daan!

Camille Dreyfus Teacher-Scholar Award (6/2012)

Adam received this award. Hooray! Thank you, Dreyfus brothers!

New faces in the lab (6/2012)

Dian Yang is a rotation student from SEAS. He is working on development of our SLIM camera. Cameron Myhrvold is a rotation student from Systems Biology. He is working on a SPIM microscope. Welcome Dian and Cameron! Stay tuned to learn about SLIM and SPIM.

Yiqiao wins science prizes (5/2012)

Yiqiao got two prizes. Nice work, Yiqiao!
  • Chinese Government award for outstanding self-financed students abroad, from the Consulate General of China
  • 2012 SPIE Scholarship in Optics & Photonics

Adam gets tenure (3/2012)

Thanks to everyone in the lab whose hard work brought this about.

Degradation-induced motion in biogels, published in Soft Matter (3/2012)

Jen's paper on "Motion Induced by Asymmetric Enzymatic Degradation of Hydrogels" just came out. She showed that enzyme gradients could lead to directional transport of beads embedded in a biogel. And then she showed why this happens. Congratulations, Jen!

New faces in the lab (3/2012)

Elisabeth Meyer is an undergrad and will work with Alex on DNA mechanics. Namrata Anand is also an undergrad, and she is working with Team VIP on Voltage Indicating Proteins. Feng Tian is a rotation student from MCB and is also working on applications of voltage imaging to neuronal stem cells. Welcome all!

Sabrina finishes postdoc, starts new lab at McGill (1/2012)

Congratulations to Sabrina and all the best in the new job!

Blinking Neurons published in Nature Methods (11/2011)

Fluorescence of Archaerhodopsin 3 is very sensitive to membrane potential (and it responds in < 500 microseconds!). Rat neurons expressing Arch emit a flash of fluorescence every time they fire. Here's the paper. Check out Supplementary Movies 1 and 3.

ABEL trap patent issues (11/2011)

Here's the patent on the ABEL trap, joint with W. E. Moerner.

Jeehae Park joins lab (11/2011)

Jeehae did her PhD in the lab of TJ Ha at UIUC on single-molecule studies of protein dynamics. She'll be applying her skills to design better voltage indicating proteins. Welcome Jeehae!

Optical imaging of nanomagnetic fields (11/2011)

Hohjai and Nan's paper came out in Nano Letters: "Mapping Nanomagnetic Fields Using a Radical Pair Reaction." They used a fluorescent chemical indicator of magnetism to look at the fields around microfabricated structures. Visualizing quantum coherence in a room-temperature liquid--pretty cool!

Ultrasensitive measurements of microbial rhodopsin photocycles (10/2011)

Halil's paper came out in Photochemistry and Photobiology: "Ultrasensitive Measurements of Microbial Rhodopsin Photocycles Using Photochromic FRET." Halil attached a fluorophore to a microbial rhodopsin so that only some states in the rhodopsin photocycle quenched the fluorophore (via changes in the spectral overlap between fluorophore emission and rhodopsin absorption). This procedure converts changes in absorption into changes in fluorescence. Well done, Halil!

Adam named John L. Loeb Associate Professor of the Natural Sciences (9/2011)

Thank you Mr. Loeb!

Blinking bacteria published in Science (7/14/2011)

Congratulation to Joel, Daniel, and Adam D. on their paper on Electrical Spiking in Escherichia coli Probed with a Fluorescent Voltage-Indicating Protein. PROPS for a job well done. See also news stories in ScienceNow, LiveScience, Nature, Science Signaling, and Biotechniques.

Markov model Journal Club wheel

Ever have trouble deciding who should present for your lab's journal club? Jen came to the rescue with a Matlab-based Markov model to help make the choice. Feel free to copy and adapt the code.

Perspective on ABEL trapping (June 2011)

Adam and Alex wrote a perspective on a paper by Wang and Moerner in ACS Nano. We discuss the question: Scientists can trap single small molecules in solution. Now what?

Adam talks a lot (June 2011)

Adam recently gave three non-research talks:
  • Commencement address at Hunter College High School, and receipt of 2011 Distinguished Graduate Award. Here's the text of his speech.
  • Keynote address at the United Nimba Citizens Council annual meeting, on the topic of Science Education in Liberia. Pictures.
  • A three-hour workshop on undergraduate science education for ten visiting scientists from Ghana and Mali as part of the Novartis/Seeding Labs Fellows Program.

New faces in the lab (June 2011)

Lucy Rosenbaum joins as a research technician. Lucy just graduated from BU and is taking to the lab like a duck to water. Ariana Mann is spending the summer working with Sabrina on CLIC experiments, and Rohini Shivamoggi is spending the summer in the lab synthesizing magnetically sensitive fluorescent compounds. Welcome Lucy, Ariana, and Rohini!

Physics Today article on Superchiral Light (June 2011)

Here's a nice news story describing the ideas and experiment underlying superchiral light.

Alex's paper published in PNAS (5/11/2011)

Read about Electrokinetic trapping at the one nanometer limit. Alex's ABEL trap can hold a single fluorophore, with a radius less than one nanometer, in water under ambient conditions. Does thinking about this make your molecules jiggle? See also the news story on

Jen garners teaching prizes (5/05/2011)

Jennifer Hou made a clean sweep of Harvard's teaching prizes for graduate students. She recently received: Derek C. Bok Award for Excellence in Graduate Student Teaching of Undergraduates, Harvard University Certificate of Distinction in Teaching from the Bok Center, Harold T. White Prize for Excellence in Teaching from the Physics Dept. Good job, Jen!

Postdocs get jobs (5/05/2011)

Two former and one current postdoc find gainful employment. Prashant Jain will join the Chemistry Department at UIUC. Halil Bayraktar will join the chemistry department at Koc University, Turkey. Sabrina Leslie will join the physics department at McGill. Employment is on the rise!

Yiqiao's paper published in Science (4/14/2011)

Read about Enhanced Enantioselectivity in Excitation of Chiral Molecules by Superchiral Light. This paper puts a new twist on light.

Sloan Fellowship for Adam (2/15/2011)

Thank you to the Sloan Foundation!

Welcome to Dougal MacLaurin (1/25/2011)

Dougal is a new rotation student from physics. He hails from Australian National University. Welcome Dougal!

Halil finishes his postdoc (12/15/2010)

All the best and thank you Halil for contributing so much to the lab!

Adam meets President Obama (12/13/2010)

PECASE ceremony in Washington DC. President Obama says "Congratulations." Adam says "Thank you."

Nan has two papers published (11/22/2010)

Optical imaging through scattering media via magnetically modulated fluorescence is in Optics Express. Check out the movie of a small magnet changing the fluorescence of a solution! Local geometry of electromagnetic fields and its role in molecular multipole transitions will come out in J. Phys. Chem. B. No movies here, but plenty of interesting theory. Nice work Nan!

PECASE (11/05/2010)

Adam received the Presidential Early Career Award for Scientists and Engineers (PECASE). Here is the announcement. Thank you, Mr. President!

Joint Research Grant in Basice Neuroscience (10/19/2010)

Florian Engert's lab and our lab share a research grant for neuroscience. Now we can put our brains together.

NIH New Innovator Award (9/30/2010)

We got an NIH New Innovator Award. Here is the announcement. Hooray! Our lab's bake sale is cancelled until further notice.

Workshop on Science Research and Education in Liberia (7/1/2010)

Adam spent two weeks in Liberia with Ben Rapoport and Liz Wood. We held a workshop on science research and education for faculty at the University of Liberia. About sixty people participated. Here are photos of some of our experiments, and here is our syllabus.

Sabrina gets Best Poster Prize at Single Molecule Gordon Conference (7/1/2010)

Her poster described the wonderful single-molecule images you can take with CLIC. Nice work Sabrina!

Convex Lens Induced Confinement (CLIC) for imaging single molecules (6/17/2010)

Sabrina and Alex had a paper in Analytical Chemistry showing that you can image single molecules much better when you squeeze the molecules between a convex lens and a coverslip. Squish. Here's a story in C&E News on this work. See also this article in Technology Review.

Confining Molecules for Single-Molecule Spectroscopy (5/30/2010)

A review article, in honor of W. E. Moerner's winning the Wolf Prize, just came out in the Israeli Journal of Chemistry. Squeezing molecules by just the right amount can make them much easier to study.

Cover story in Physical Review Letters: Optical Chirality and Its Interaction with Matter (4/23/2010)

Yiqiao's paper just came out and is on the front cover of PRL. We showed that there exist simple solutions to Maxwell's equations with much greater chiral asymmetry, in some regions of space, than is found in circularly polarized light. Here is a story in Science News about this work. Yippee!

Welcome to Veena Venkatachalam (4/15/10)

Veena is in the Harvard-MIT MD-PhD program, and once upon a time helped launch "eau d'e coli", an evocative blend of banana and mint-scented microbes. Now she's working her magic on proteorhodopsin.

Welcome to Aili Klein (4/15/10)

Aili is a first-year undergraduate at Harvard. She will be working with Sabrina on studying molecules in extreme confinement. Welcome Aili!

Mulbah Jackollie visits Harvard and MIT (2/5/10)

Jackollie is the director of Booker Washington Institute, the largest technical and vocational school in Liberia. He spent several days meeting with students and faculty at Harvard and MIT and with local NGOs. Here are some photos of his visit.

Welcome to Daniel Hochbaum (2/1/10)

Daniel was an undergrad at MIT and has made the big move up river. He'll be working on new imaging schemes using microbial rhodopsins. Welcome Daniel!

Welcome to Hohjai Lee (1/4/10)

Hohjai comes to us from Graham Fleming's group at Berkeley, where he worked on coherent energy transfer in photosynthetic systems. Here Hohjai will work on coherent control of chemical reactions using magnetic spin manipulation. Welcome Hohjai!

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.

Welcome Sabrina (3/16/09)

Sabrina Leslie is a new postdoc in the lab. Sabrina did her PhD with Dan Stamper-Kurn at Berkeley. Welcome Sabrina!

Speedy Scientists (3/15/09)

We competed in the Ras na hEireann/Chemistry Department St. Patrick's Day race, with 100% of the lab participating! Jen and Adam clocked the fastest female and male times among the chemists. Rock on! Here are some photos and the results. Special thanks to our Cheerleaders.

Faraday Rotation in Magnetic Nanocrystals (3/14/09)

Prashant's paper on Surface Plasmon Resonance Enhanced Magneto-Optics (SuPREMO) came out in NanoLetters. Supremely Cool!

Students present at Biophysical Society Meeting (3/1/09)

Halil, Jen, Alex, and Joel each presented a poster at BPS. You can read about Spectral Shift FRET as a probe of microbial rhodopsins, microbial motion in mucus, an improved ABEL trap for single molecules, or the spectroscopy of squid rhodopsins.

Welcome Joel (2/15/09)

Joel Kralj joins us from the lab of Ken Rothschild at BU. Joel knows all about microbial rhodopsins, and will be teaching these molecules some nifty new tricks.

Redox Cycling paper published (1/22/09)

This was Adam's undergraduate research project. It took a decade to publish, but it was worth the wait! Here it is, published as an article in JACS. Thanks to all the coauthors for making this happen.

Farewell Prashant, welcome Min Ju (11/30/08)

Prashant has left for his Miller Fellowship at Berkeley. He promises to send us a postcard of the sun. Here are photos of some athletic exploits that accompanied his departure. Min Ju Shon is a first-year student in Chemistry, coming from Seoul National University. Welcome Min Ju!

Pet Elephant!

Check out the newest addition to our family: a pet elephant.

Comings and goings

Welcome to postdoc Halil Bayraktar! Halil just finished his PhD in chemistry at UMass Amherst and will be working on trapping bacteriorhodopsins. Also welcome to undergrads Malcolm Campbell and Arhana Chattopadhyay. Malcolm is building a "biotic camera" (stay tuned to find out what that means), and Arhana is working on using live yeast as a chromatographic separation medium. Orpha Rivera is departing to grad school to study graphic design. Bon Voyage Orpha!

Lab outing (5/18/08)

We took a hike up Mount Monadnock. And then we got some real exercise.

Hardware trap paper published (5/2/08)

Adam's paper with W. E. on an ABEL trap that performs feedback photon-by-photon using hardware tracking was published in Optics Express.

First trapping (4/30/08)

Alex got the ABEL trap working and trapped our first beads. Hooray!

Nan starts rotation (2/4/08)

Nan Yang studied physics at University of Toronto and has a background in optics. Welcome Nan!

Students take the plunge (2/4/08)

Alex and Yiqiao officially joined the lab. Hooray!

Katie is promoted! (2/4/08)

Katie will be working with the Liu Group from now on. Good luck Katie, and thanks!

Labwarming party (1/14/08)

Thanks to the contractors and building staff for making us such beautiful labs! Check out the labs (and the party) here.

Sijia finishes rotation (1/14/08)

Thanks to Sijia for his hard work during the rotation, and for all his help opening Thorlabs packages :)

New photo album up (12/18/07)

A new Picasa album shows some snapshots of good times in the lab.

Welcome undergrads! (12/10/07)

Lin Cong, a physics Junior, and David Gootenberg, a freshman, have started hanging out with us in the lab. Welcome Lin and David!

Prashant Jain joins as first postdoc (11/16/07)

Prashant is finishing his PhD with Mostafa El-Sayed at Georgia Tech. He will start in mid-February. Welcome Prashant!

Rotating rotation students (11/14/07)

Thanks to Stephen for all of his hard work during the rotation, and best of luck in the Park Group. Welcome to Sijia Lu! It's great to have you around.


A patent for putting nanoparticles on scanning probe tips finally issued. This patent was filed in 2002 based on work done in 2000 at the IBM Watson Research Center, with Chuck Black, Chris Murray, and Bob Sandstrom. Hooray!

Group Open House (10/15/07)

We had our Group Open House. Thanks to all who came and helped relieve us of excess beer. There were demos of Brownie-in-Motion, and the future of fashion.

Cleanroom training (10/10/07)

We all got trained in the McKay cleanrooms. The students looked good in their bunnysuits.

Katie O'Brien joins as new Admin. Asst. (9/24/07)

Katie comes to us from a background in publishing and will be taking over from Cheryl Ryder. Thanks to Cheryl for all her hard work and patience in the startup phase, and welcome Katie!

New rotation student (9/24/07)

Jennifer Hou from the physics dept. signed on for a rotation. Welcome Jennifer!

New rotation student (9/14/07)

Yiqiao Tang, a G1 in physics, started his rotation. Welcome Yiqiao!

Group size triples (9/6/07)

In what is likely a unique occurrence, the group size tripled in a single day: Alex and Stephen started their rotations.

Systems Biology PhD program (8/20/07)

We're now part of the Systems Biology Phd Program at Harvard Med School. We like systems, and we like biology--so it's a winning combination!

Technology Review TR35 (8/15/07)

Adam was awarded a TR35 prize by MIT's Technology Review Magazine for young innovators under the age of 35.

Dreyfus award (8/6/07)

Adam received the Camille and Henry Dreyfus Award for New Faculty. This award will support research into the local and nonlinear mechanical properties of DNA.

First equipment arrives (8/1/07)

We got two 4' x 8' x 1' Newport optical tables, an Olympus IX-71 microscope, and, of course, the most essential piece of lab equipment ever created.

©2015 Adam E. Cohen