%0 Book Section %1 statphys23_0423 %A Levi, P. %A Mecke, K. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K biomolecules confined fluctuations microfluidics polymers semiflexible statphys23 topic-7 %T Confined Thermal Fluctuations of Biomolecules - A Self-Consistent Theory %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=423 %X Biomolecules and membranes are always subject to thermal fluctuations which have an influence on their mechanical properties. These fluctuations are spatially constraint by walls in microchannels or by neighbouring polymer networks or binding forces in living cells. For confinement modelled by a parabolic potential an analytic expression is derived for the distribution of the end-to-end distance of a semiflexible polymer 1. It elucidates the mechanical and statistical properties of biomolecules. For more realistic confinement a self-consistent ansatz is developed, that gives the end-to-end distribution explicitly even for hard wall confinement. This result is in good quantitative agreement with fluorescence microscopy data for actin filaments in rectangularly shaped microchannels. This allows for unambiguous determination of the persistence length and the dependence of statistical properties like Odijk's deflection length on the channel width. It is shown that by neglecting the effects of confinement one significantly overestimates bending rigidities of filaments 1. For a wedge-shaped microchannel we make quantitative predictions of an entropic drag force pulling the polymer towards the broader side. We also apply the self-consistent theory to bundle formation processes mediated by linker molecules and find a tightly bound state when the linker strength exceeds a critical value. We confirm previous simulation results on the dependence of this value on system properties like linker length 2. In addition our analytic theory allows studying bundle formation in confining environments like microchannels and provides an explicit expression for the partition function necessary to analyze the near-equilibrium dynamics of bundling processes. itemize ıtem1 P. Levi and K. Mecke, Radial distribution function for semiflexible polymers confined in microchannels, Europhysics Letters in press (2007), see also cond-mat/0612596 ıtem2 J. Kierfeld, T. Kuehne and R. Lipowsky, Discontinuous unbinding transition of filament bundles, Physical Review Letters 95:038102 (2005) itemize

@incollection{statphys23_0423, abstract = {Biomolecules and membranes are always subject to thermal fluctuations which have an influence on their mechanical properties. These fluctuations are spatially constraint by walls in microchannels or by neighbouring polymer networks or binding forces in living cells. For confinement modelled by a parabolic potential an analytic expression is derived for the distribution of the end-to-end distance of a semiflexible polymer [1]. It elucidates the mechanical and statistical properties of biomolecules. For more realistic confinement a self-consistent ansatz is developed, that gives the end-to-end distribution explicitly even for hard wall confinement. This result is in good quantitative agreement with fluorescence microscopy data for actin filaments in rectangularly shaped microchannels. This allows for unambiguous determination of the persistence length and the dependence of statistical properties like Odijk's deflection length on the channel width. It is shown that by neglecting the effects of confinement one significantly overestimates bending rigidities of filaments [1]. For a wedge-shaped microchannel we make quantitative predictions of an entropic drag force pulling the polymer towards the broader side. We also apply the self-consistent theory to bundle formation processes mediated by linker molecules and find a tightly bound state when the linker strength exceeds a critical value. We confirm previous simulation results on the dependence of this value on system properties like linker length [2]. In addition our analytic theory allows studying bundle formation in confining environments like microchannels and provides an explicit expression for the partition function necessary to analyze the near-equilibrium dynamics of bundling processes. \begin{itemize} \item[[1]] P. Levi and K. Mecke, {\sl Radial distribution function for semiflexible polymers confined in microchannels}, Europhysics Letters {\sl in press} (2007), {\sl see also cond-mat/0612596} \item[[2]] J. Kierfeld, T. Kuehne and R. Lipowsky, {\sl Discontinuous unbinding transition of filament bundles}, Physical Review Letters {\bf 95}:038102 (2005) \end{itemize}}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Levi, P. and Mecke, K.}, biburl = {https://www.bibsonomy.org/bibtex/24d748302e7a43c211561d1c2f43a989f/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {89c26cc868033692b568165f3bb8d738}, intrahash = {4d748302e7a43c211561d1c2f43a989f}, keywords = {biomolecules confined fluctuations microfluidics polymers semiflexible statphys23 topic-7}, month = {9-13 July}, timestamp = {2007-06-20T10:16:20.000+0200}, title = {Confined Thermal Fluctuations of Biomolecules - A Self-Consistent Theory}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=423}, year = 2007 }