Prof. Jens-Christian D. Meiners Profile

Prof. Jens-Christian D. Meiners

Professor of Physics at Univ of Michigan

SPIE Involvement:

Author

Proceedings Article | 21 February 2017 Paper

Quantitative fluorescence correlation spectroscopy on DNA in living cells

Cameron Hodges, Rudra Kafle, Jens-Christian Meiners

Proceedings Volume 10071, 1007102 (2017) https://doi.org/10.1117/12.2251409

KEYWORDS: Fluorescence correlation spectroscopy, Quantitative analysis, Systems modeling, Microscopy, Complex systems, Macromolecules, Microscopes, Correlation function, Photons, Particles, Computer simulations

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Proceedings Article | 25 August 2015 Paper

Artifacts from photobleaching and dye-dissociation in fluorescence correlation spectroscopy

Rudra Kafle, Molly Liebeskind, Julia Bourg, Elizabeth White, Jens-Christian Meiners

Proceedings Volume 9548, 95481M (2015) https://doi.org/10.1117/12.2191402

KEYWORDS: Fluorescence correlation spectroscopy, Photons, Molecules, Environmental sensing, Particles, Solids, MATLAB, Spectroscopy, Correlation function, Molecular spectroscopy

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Proceedings Article | 10 October 2012 Paper

Using DNA looping to measure sequence dependent DNA elasticity

Alan Kandinov, Krishnan Raghunathan, Jens-Christian Meiners

Proceedings Volume 8458, 845816 (2012) https://doi.org/10.1117/12.945930

KEYWORDS: Optical tweezers, Particles, Molecules, Glasses, Microscopy, Data modeling, Proteins, Microscopes, Biophysics, Physics

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Proceedings Article | 9 September 2011 Paper

Mechanics of DNA: sequence dependent elasticity

Krishnan Raghunathan, Yih-Fan Chen, Justin Blaty, Benjamin Arthur Juliar, Joshua Milstein, Jens-Christian Meiners

Proceedings Volume 8097, 80970C (2011) https://doi.org/10.1117/12.895297

KEYWORDS: Optical tweezers, Mechanics, Crystals, Polymers, Data modeling, Genetics, Molecules, 3D modeling, Biomedical optics, Biomedical engineering

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Proceedings Article | 28 August 2010 Paper

Protein-mediated DNA looping in a fluctuating micromechanical environment

J. Milstein, Yih-Fan Chen, Jens-Christian Meiners

Proceedings Volume 7762, 77620B (2010) https://doi.org/10.1117/12.860048

KEYWORDS: Molecules, Proteins, Environmental sensing, Cytoskeletons, Genetics, Stochastic processes, Optical tweezers, Modulation, Solids, Control systems

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Proceedings Article | 20 August 2009 Paper

Boundary-condition dependent elasticity of short double-stranded DNA molecules

Yih-Fan Chen, K. Raghunathan, David Wilson, Jens-Christian Meiners

Proceedings Volume 7400, 740003 (2009) https://doi.org/10.1117/12.827671

KEYWORDS: Molecules, Optical tweezers, Glasses, Calibration, Microscopes, CCD cameras, Beam splitters, Polymers, Objectives, Data modeling

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Proceedings Article | 5 September 2007 Paper

Stretching sub-micron DNA fragments with optical tweezers

Yih-Fan Chen, Gerhard Blab, Jens-Christian Meiners

Proceedings Volume 6644, 664403 (2007) https://doi.org/10.1117/12.736824

KEYWORDS: Optical tweezers, Molecules, Glasses, Diffraction, Optical testing, Microscopes, Molecular lasers, Objectives, Calibration, Telescopes

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Proceedings Article | 8 June 2007 Paper

Understanding the role of thermal fluctuations in DNA looping

David Wilson, Todd Lillian, Sachin Goyal, Alexei Tkachenko, Noel Perkins, Jens-Christian Meiners

Proceedings Volume 6602, 660208 (2007) https://doi.org/10.1117/12.724717

KEYWORDS: Proteins, Crystals, Physics, Biophysics, Mechanical engineering, Genetics, Polymers, Biomedical optics, Energy efficiency, Differential equations

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Proceedings Article | 18 August 2005 Paper

Dynamics of single DNA molecules under femtonewton forces

Rajalakshmi Nambiar, Jens-Christian Meiners

Proceedings Volume 5930, 593010 (2005) https://doi.org/10.1117/12.615985

KEYWORDS: Molecules, Optical tweezers, Microscopes, Particles, Bragg cells, Polymers, Optical spheres, Modulation, Objectives, Signal detection

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Studying the thermal fluctuations of DNA molecules reveals not only a wealth of interesting equilibrium and nonequilibrium statistical mechanics, but is also of importance for understanding the dynamics of DNA in vivo. An instance of the latter is in the context of regulatory functions that require collaborative interactions of distant operator sites on the DNA molecule. These thermal fluctuations are extremely sensitive to mechanical constraints, such as supercoiling or mechanical tension in the DNA. The natural force scale fc on which these fluctuations are sensitive to tension is related to the persistence length l_p by f_c = k_BT/l_p = 80 fN, which is generally considered small for a crowded cellular environment. We are studying the dynamics of single DNA molecules under tension under equilibrium and non-equilibrium conditions using a modified scanning-line laser trap. This technique allows us to apply a constant force between 20 fN and 3 pN to a λ-DNA molecule while we study its behavior under two different conditions: 1) nonequilibrium studies in which we observe the relaxation trajectory of a highly extended DNA molecule as it returns to its equilibrium conformation against an applied optical force, and 2) equilibrium studies which measure fluctuations in the extension of the molecule about its mean with sub-millisecond time resolution as a function of its extension. In the nonequilibrium studies we find a marked deviation from predictions derived from the wormlike-chain (WLC) model for extended DNA molecules. In the equilibrium studies we compute the time-correlation functions of the fluctuations to determine their time constants, and model them with a simple bead-and-spring model. We observe a decrease of the fundamental time constant with increasing extension of the molecule. This suggests that the change in spring constant dominates changes in the intra-chain hydrodynamic coupling between segments as the Gaussian coil unravels into an extended conformation.