Characterizing concentrated, multiply scattering, and actively driven fluorescent systems with confocal differential dynamic microscopy

Citation:

Lu, P. J. ; Giavazzi, F. ; Angelini, T. E. ; Zaccarelli, E. ; Jargstorff, F. ; Schofield, A. B. ; Wilking, J. N. ; Romanowsky, M. B. ; Weitz, D. A. ; Cerbino, R. Characterizing concentrated, multiply scattering, and actively driven fluorescent systems with confocal differential dynamic microscopy. Physical Review Letters 2012, 108. Copy at http://www.tinyurl.com/kbjj7gj
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Abstract:

We introduce confocal differential dynamic microscopy (ConDDM), a new technique yielding information comparable to that given by light scattering but in dense, opaque, fluorescent samples of micron-sized objects that cannot be probed easily with other existing techniques. We measure the correct wave vector q-dependent structure and hydrodynamic factors of concentrated hard-sphere-like colloids. We characterize concentrated swimming bacteria, observing ballistic motion in the bulk and a new compressed-exponential scaling of dynamics, and determine the velocity distribution; by contrast, near the coverslip, dynamics scale differently, suggesting that bacterial motion near surfaces fundamentally differs from that of freely swimming organisms.

Notes:

Times Cited: 10

Last updated on 04/17/2014