Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/53339
Title: Force Spectroscopy with Dual-Trap Optical Tweezers: Molecular Stiffness Measurements and Coupled Fluctuations Analysis
Author: Ribezzi-Crivellari, M.
Ritort Farran, Fèlix
Keywords: Biofísica
ADN
Polímers
Elasticitat
Aparells i instruments científics
Molècules
Espectroscòpia
Biophysics
DNA
Polymers
Elasticity
Scientific apparatus and instruments
Molecules
Spectrum analysis
Issue Date: 7-Nov-2012
Publisher: Biophysical Society
Abstract: ABSTRACT Dual-trap optical tweezers are often used in high-resolution measurements in single-molecule biophysics. Such measurements can be hindered by the presence of extraneous noise sources, the most prominent of which is the coupling of fluctuations along different spatial directions, which may affect any optical tweezers setup. In this article, we analyze, both from the theoretical and the experimental points of view, the most common source for these couplings in dual-trap optical-tweezers setups: the misalignment of traps and tether. We give criteria to distinguish different kinds of misalignment, to estimate their quantitative relevance and to include them in the data analysis. The experimental data is obtained in a, to our knowledge, novel dual-trap optical-tweezers setup that directly measures forces. In the case in which misalignment is negligible, we provide a method to measure the stiffness of traps and tether based on variance analysis. This method can be seen as a calibration technique valid beyond the linear trap region. Our analysis is then employed to measure the persistence length of dsDNA tethers of three different lengths spanning two orders of magnitude. The effective persistence length of such tethers is shown to decrease with the contour length, in accordance with previous studies.
Note: Reproducció del document publicat a: http://dx.doi.org/10.1016/j.bpj.2012.09.022
It is part of: Biophysical Journal, 2012, vol. 103, num. 9, p. 1919-1928
Related resource: http://dx.doi.org/10.1016/j.bpj.2012.09.022
URI: http://hdl.handle.net/2445/53339
ISSN: 0006-3495
Appears in Collections:Articles publicats en revistes (Física de la Matèria Condensada)

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