Absolute negative particle mobility: Brownian motion

Noise effects in technological applications, far from being a nuisance, can be exploited with advantage — for example, unavoidable thermal fluctuations have found application in the transport and sorting of colloidal particles 1 , 2 , 3 and biomolecules 4 , 5 , 6 . Here we use a microfluidic system...

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Bibliographic Details
Published in:Nature (London) 2005-08, Vol.436 (7053), p.928-928
Main Authors: Ros, Alexandra, Eichhorn, Ralf, Regtmeier, Jan, Duong, Thanh Tu, Reimann, Peter, Anselmetti, Dario
Format: Article
Language:English
Subjects:
brief-communication
Humanities and Social Sciences
multidisciplinary
Science
Science (multidisciplinary)
Online Access:Get full text
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Summary:Noise effects in technological applications, far from being a nuisance, can be exploited with advantage — for example, unavoidable thermal fluctuations have found application in the transport and sorting of colloidal particles 1 , 2 , 3 and biomolecules 4 , 5 , 6 . Here we use a microfluidic system to demonstrate a paradoxical migration mechanism in which particles always move in a direction opposite to the net acting force (‘absolute negative mobility’) as a result of an interplay between thermal noise, a periodic and symmetric microstructure, and a biased alternating-current electric field. This counterintuitive phenomenon could be used for bioanalytical purposes, for example in the separation and fractionation of colloids, biological molecules and cells.
ISSN:0028-0836
1476-4687
DOI:10.1038/436928a