Now showing items 1-20 of 36

    • All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins 

      Hochbaum, Daniel R.; Zhao, Yongxin; Farhi, Samouil L.; Klapoetke, Nathan; Werley, Christopher A.; Kapoor, Vikrant; Zou, Peng; Kralj, Joel M.; Maclaurin, Dougal; Smedemark-Margulies, Niklas; Saulnier, Jessica L.; Boulting, Gabriella L.; Straub, Christoph; Cho, Yong Ku; Melkonian, Michael; Wong, Gane Ka-Shu; Harrison, D. Jed; Murthy, Venkatesh N.; Sabatini, Bernardo; Boyden, Edward S.; Campbell, Robert E.; Cohen, Adam E. (2014)
      All-optical electrophysiology—spatially resolved simultaneous optical perturbation and measurement of membrane voltage—would open new vistas in neuroscience research. We evolved two archaerhodopsin-based voltage indicators, ...
    • All-Optical Interrogation of Neural Circuits 

      Emiliani, V.; Cohen, Adam Ezra; Deisseroth, K.; Hausser, M. (Society for Neuroscience, 2015)
      There have been two recent revolutionary advances in neuroscience: First, genetically encoded activity sensors have brought the goal of optical detection of single action potentials in vivo within reach. Second, optogenetic ...
    • Anti-Brownian Traps for Studies on Single Molecules 

      Fields, Alexander; Cohen, Adam Ezra (Elsevier BV, 2010)
      Until recently, Brownian motion was seen as an immutable feature of small particles in room-temperature liquids. Molecules, viruses, organelles, and small cells jiggle incessantly due to countless collisions with thermally ...
    • Bright and Fast Multicoloured Voltage Reporters via Electrochromic FRET 

      Zou, Peng; Zhao, Yongxin; Douglass, Adam D.; Hochbaum, Daniel Ron; Brinks, Daan; Werley, Christopher A; Harrison, D. Jed; Campbell, Robert E.; Cohen, Adam Ezra (Nature Publishing Group, 2014)
      Genetically encoded fluorescent reporters of membrane potential promise to reveal aspects of neural function not detectable by other means. We present a palette of multicoloured brightly fluorescent genetically encoded ...
    • Bringing Bioelectricity to Light 

      Cohen, Adam Ezra; Venkatachalam, Veena (Annual Reviews, 2014)
      Any bilayer lipid membrane can support a membrane voltage. The combination of optical perturbation and optical readout of membrane voltage opens the door to studies of electrophysiology in a huge variety of systems previously ...
    • Bringing bioelectricity to light: all-optical electrophysiology using microbial rhodopsins 

      Hochbaum, Daniel Ron (2014-10-21)
      My work has focused on the development and application of fluorescent voltage-sensitive proteins based on microbial rhodopsins. These probes led to the discovery of electrical activity in the bacterium Escherichia coli, ...
    • Chirality of Light and Its Interaction with Chiral Matter 

      Tang, Yiqiao (2013-03-18)
      This thesis conducts a systematic study on the chirality of light and its interaction with chiral matter. In the theory section, we introduce a measure of local density of chirality, applying to arbitrary electromagnetic ...
    • Chirality-Dependent Friction of Bulk Molecular Solids 

      Yang, Dian; Cohen, Adam Ezra (American Chemical Society (ACS), 2014)
      We show that the solid−solid friction between bulk chiral molecular solids can depend on the relative chirality of the two materials. In menthol and 1-phenyl-1-butanol, heterochiral friction is smaller than homochiral ...
    • Chiroptical Hot Spots in Twisted Nanowire Plasmonic Oscillators 

      Tang, Yiqiao; Sun, Li; Cohen, Adam Ezra (AIP Publishing, 2013)
      We image the chiroptical response of crossed nanowire junctions as a function of the vertical offset between the nanowires and the incident wavelength. These samples show chiroptical “hot spots” with strongly localized ...
    • Convex Lens-Induced Confinement for Imaging Single Molecules 

      Leslie, Sabrina R.; Fields, Alexander; Cohen, Adam Ezra (American Chemical Society (ACS), 2010)
      Fluorescence imaging is used to study the dynamics of a wide variety of single molecules in solution or attached to a surface. Two key challenges in this pursuit are (1) to image immobilized single molecules in the presence ...
    • Dynamics in Biological Soft Materials 

      Hou, Jennifer Hsin-I (2014-02-25)
      I present applications of imaging and spectroscopy to understand mechanical, chemical, and electrical dynamics in biological materials. The first part describes the development and characterization of a protein-based ...
    • Electrokinetic Trapping of Single Molecules, and Euler Buckling and Nonlinear Kinking of DNA 

      Fields, Alexander Preston (2013-09-30)
      I present two applications of fluorescence spectroscopy in biophysics. The first is an instrument, the anti-Brownian electrokinetic (ABEL) trap, which is capable of trapping individual small molecules in aqueous solution ...
    • Engineering microbial rhodopsins to expand the optogenetic toolkit 

      Venkatachalam, Veena (2014-10-21)
      Cellular lipid membranes can – and often do – support a transmembrane electric field, serving as biological capacitors that maintain a voltage difference between their two sides. It isn't hard to see why these ...
    • Euler buckling and nonlinear kinking of double-stranded DNA 

      Fields, Alexander P.; Meyer, Elisabeth A.; Cohen, Adam E. (Oxford University Press, 2013)
      The bending stiffness of double-stranded DNA (dsDNA) at high curvatures is fundamental to its biological activity, yet this regime has been difficult to probe experimentally, and literature results have not been consistent. ...
    • Flash Memory: Photochemical Imprinting of Neuronal Action Potentials onto a Microbial Rhodopsin 

      Venkatachalam, Veena; Brinks, Daan; Maclaurin, Dougal; Hochbaum, Daniel; Kralj, Joel; Cohen, Adam E. (American Chemical Society, 2014)
      We developed a technique, “flash memory”, to record a photochemical imprint of the activity state—firing or not firing—of a neuron at a user-selected moment in time. The key element is an engineered microbial rhodopsin ...
    • Genetically Targeted All-Optical Electrophysiology with a Transgenic Cre-Dependent Optopatch Mouse 

      Lou, Shan; Adam, Yoav; Weinstein, Eli Nathan; Williams, E.; Williams, K.; Parot, Vicente Jose; Kavokine, N.; Liberles, Stephen D; Madisen, L.; Zeng, H.; Cohen, Adam Ezra (Society for Neuroscience, 2016)
      Recent advances in optogenetics have enabled simultaneous optical perturbation and optical readout of membrane potential in diverse cell types. Here, we develop and characterize a Cre-dependent transgenic Optopatch2 mouse ...
    • Imaging GFP-Based Reporters in Neurons with Multiwavelength Optogenetic Control 

      Venkatachalam, Veena; Cohen, Adam Ezra (Elsevier BV, 2014)
      To study the impact of neural activity on cellular physiology, one would like to combine precise control of firing patterns with highly sensitive probes of cellular physiology. Light-gated ion channels, e.g., Channelrhodopsin-2, ...
    • In Honor of W.E. Moerner: Confining Molecules for Single-Molecule Spectroscopy 

      Cohen, Adam Ezra; Fields, Alexander; Hou, Jennifer Hsin-I; Leslie, Sabrina R.; Shon, Min Ju Ju (Wiley-Blackwell, 2009)
      Single-molecule spectroscopy provides a wealth of information on the dynamics and interactions of complex biological molecules. Yet these measurements are extremely challenging, partly because Brownian motion prevents ...
    • Limits on Fluorescence Detected Circular Dichroism of Single Helicene Molecules 

      Tang, Yiqiao; Cook, Timothy A.; Cohen, Adam Ezra (American Chemical Society, 2009)
      Fluorescent imaging of single helicene molecules is applied to study the optical activity of chiral fluorophores. In contrast to the previous report by Hassey et al. (Science 2006, 314, 1437), the dissymmetry factors of ...
    • A Low Affinity GCaMP3 Variant (GCaMPer) for Imaging the Endoplasmic Reticulum Calcium Store 

      Henderson, Mark J.; Baldwin, Heather A.; Werley, Christopher A.; Boccardo, Stefano; Whitaker, Leslie R.; Yan, Xiaokang; Holt, Graham T.; Schreiter, Eric R.; Looger, Loren L.; Cohen, Adam E.; Kim, Douglas S.; Harvey, Brandon K. (Public Library of Science, 2015)
      Endoplasmic reticulum calcium homeostasis is critical for cellular functions and is disrupted in diverse pathologies including neurodegeneration and cardiovascular disease. Owing to the high concentration of calcium within ...