Open Access Nano Express

Thermal noise in aqueous quadrupole micro- and nano-traps

Jae Hyun Park and Predrag S Krstić*

Author Affiliations

Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA

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Nanoscale Research Letters 2012, 7:156  doi:10.1186/1556-276X-7-156

Published: 27 February 2012


Recent simulations and experiments with aqueous quadrupole micro-traps have confirmed a possibility for control and localization of motion of a charged particle in a water environment, also predicting a possibility of further reduction of the trap size to tens of nano-meters for trapping charged bio-molecules and DNA segments. We study the random thermal noise due to Brownian motion in water which significantly influences the trapping of particles in an aqueous environment. We derive the exact, closed-form expressions for the thermal fluctuations of position and velocity of a trapped particle and thoroughly examine the properties of the rms for the fluctuations as functions of the system parameters and time. The instantaneous signal transferring mechanism between the velocity and position fluctuations could not be achieved in the previous phase-average approaches.

aqueous quadrupole trap; Brownian motion; random thermal noise; rms fluctuation; charged bio-molecule; DNA sequencing