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Issue 24, 2011
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Multiplexing superparamagnetic beads driven by multi-frequency ratchets

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Here, we explore the single particle dynamics of superparamagnetic beads exposed to multifrequency ratchets. Through a combination of theory, simulation, and experiment, we determine the important tuning parameters that can be used to implement multiplexed separation of polydisperse colloidal mixtures. In particular, our results demonstrate that the ratio of driving frequencies controls the transition between open and closed trajectories that allow particles to be transported across a substrate. We also demonstrate that the phase difference between the two frequencies controls not only the direction of motion but also which particles are allowed to move within a polydisperse mixture. These results represent a fundamentally different approach to colloidal separation than the previous methods which are based on controlling transitions between phase-locked and phase-slipping regimes, and have a higher degree of multiplexing capabilities that can benefit the fields of biological separation and sensing as well as provide crucial insights into general ratchet behavior.

Graphical abstract: Multiplexing superparamagnetic beads driven by multi-frequency ratchets

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The article was received on 25 Jul 2011, accepted on 04 Oct 2011 and first published on 28 Oct 2011

Article type: Paper
DOI: 10.1039/C1LC20683D
Lab Chip, 2011,11, 4214-4220

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    Multiplexing superparamagnetic beads driven by multi-frequency ratchets

    L. Gao, M. A. Tahir, L. N. Virgin and B. B. Yellen, Lab Chip, 2011, 11, 4214
    DOI: 10.1039/C1LC20683D

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