Applied Physics

Canceling Brownian Motion

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Science  18 Mar 2005:
Vol. 307, Issue 5716, pp. 1695
DOI: 10.1126/science.307.5716.1695a

One problem in trapping small particles or cells in solution for further study is the ever-present jostling caused by Brownian motion. Cohen and Moerner have developed an anti-Brownian electrophoretic, or ABEL, trap that cancels Brownian motion. Particle movement was followed via fluorescence microscopy. Images were acquired and processed in real time, and the resulting analysis was used to apply voltages to a set of four electrodes, which create a gap of 10 to 15 μm around the particle. The applied electric fields create electrophoretic drift that cancels Brownian motion in the plane. Excursions of polystyrene nanospheres of more than 5 μm from the center of the trap were rare. — PDS

Appl. Phys. Lett. 86, 093109 (2005).

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