Using Feedback Control of Microflows to Independently Steer Multiple Particles

Armani, M.; Chaudhary, Satej; Probst, Roland; Shapiro, Benjamin

doi:10.1109/jmems.2006.878863

Cited by 98 publications

(94 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Experimental demonstrations of closed-loop, singleparticle tracking have included two-dimensional [1,2,3,4] and three-dimensional [5,6] tracking with piezo-electric actuation and two-dimensional control of individual [7,8,9] and multiple [10,11] particles with electrophoretic actuation. Concurrently, theoretical results have been developed for understanding the statistics and performance limits of these new control systems [3,4,12,13,14,15,16,10,11,17]. However, a comprehensive theory has not been previously available.…”

Section: Introductionmentioning

confidence: 99%

Fluctuations in closed-loop fluorescent particle tracking

Berglund¹,

McHale²,

Mabuchi³

2007

Opt. Express

View full text Add to dashboard Cite

Abstract:We present a comprehensive theory of closed-loop particle tracking for calculating the statistics of a diffusing fluorescent particle's motion relative to the tracking lock point. A detailed comparison is made between the theory and experimental results, with excellent quantitative agreement found in all cases. A generalization of the theory of (open-loop) fluorescence correlation spectroscopy is developed, and the relationship to previous results is discussed. Two applications of the statistical techniques are given: a method for determining a tracked particle's localization and an algorithm for rapid particle classification based on real-time analysis of the tracking control signal.

show abstract

Section: Introductionmentioning

confidence: 99%

Fluctuations in closed-loop fluorescent particle tracking

Berglund¹,

McHale²,

Mabuchi³

2007

Opt. Express

View full text Add to dashboard Cite

show abstract

“…One tracks the Brownian motion of a molecule and then imposes a body force that counteracts this motion. A variety of schemes have been proposed (16)(17)(18) and implemented (19)(20)(21)(22), differing in the method of tracking and the source of the restoring force. Here we apply our anti-Brownian electrokinetic (ABEL) trap that uses video tracking and electrokinetic feedback and is capable of trapping objects as small as individual proteins in solution (23).…”

Section: Experimental Methodsmentioning

confidence: 99%

Principal-components analysis of shape fluctuations of single DNA molecules

Cohen

Moerner

2007

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Thermal fluctuations agitate molecules in solution over a broad range of times and distances. By passively watching the shape fluctuations of a thermally driven biomolecule, one can infer properties of the underlying interactions that determine the motion. We applied this concept to single molecules of fluorescently labeled -DNA, a key model system for polymer physics. In contrast to most other single-molecule DNA experiments, we examined the unstretched, equilibrium state of DNA by using an anti-Brownian electrokinetic trap to confine the center of mass of the DNA without perturbing its internal dynamics. We analyze the longwavelength conformational normal modes, calculate their spring constants, and measure linear and nonlinear couplings between modes. The modes show strong signs of nonlinear hydrodynamics, a feature of the underlying equations of polymer dynamics that has not previously been reported and is neglected in the widely used Rouse and Zimm approximations.DNA dynamics ͉ single molecule ͉ hydrodynamic interactions ͉ polymer physics T he simplest model of a linear polymer is a chain of beads joined by springs. In the Rouse model (1), each bead is a Brownian diffuser with the same drag and diffusion coefficients it would have in the absence of other beads. This model neglects the fact that each bead is subject to the time-varying flow fields produced by the other diffusing beads. This hydrodynamic interaction (HI) renders the underlying dynamics nonlinear. The Zimm model (2) includes hydrodynamics but restores linearity through a mean-field approximation: each bead is made to interact with the average conformation of its neighbors. Subsequent work has applied sophisticated mathematical techniques to calculate corrections resulting from fluctuating hydrodynamics (3-5), but the overall significance of internal HIs to polymer dynamics remains unresolved (6).The HI is the dominant long-range force for biomolecules in aqueous buffers: it couples motion of one part of a molecule to motion of possibly remote parts of the same molecule. Thus, understanding HIs is crucial to understanding the rates of molecular events that involve large-scale conformational change such as folding of proteins and RNA, packaging of DNA, motion of molecular motors, and motion of DNA-binding proteins.Long before polymers were studied at the single-molecule level, many clever experiments applied light scattering and neutron scattering as indirect probes of polymer dynamics (7,8). However, these experiments were (i) limited to probing only the lowest one or two internal relaxations and (ii) only yielded second-order ensemble-averaged correlation functions without measuring the entire distribution of underlying states. This second property of scattering techniques makes them insensitive to deviations from the linearized Zimm theory.Higgins and Benoit (9) and Quake et al. (10) used laser tweezers to study the dynamics of partially extended DNA in solution yet failed to find deviations from the Zimm theory. This negative result is not s...

show abstract

“…As a result, the particle velocity is not expected to be uniform or constant. Control of particle velocity and trajectory can be adjusted with a feedback control based on video monitoring of the particle location with each time and then correcting the motion by adjustments into the actuation protocol [13,14]. This procedure is rather complex and it requires the use of transparent reactor materials which are not always compatible with chemical environment.…”

Section: Introductionmentioning

confidence: 99%

Magnetic actuation of catalytic microparticles for the enhancement of mass transfer rate in a flow reactor

Lisk

Bonnot

Rahman

et al. 2016

Chemical Engineering Journal

View full text Add to dashboard Cite

Permanent WRAP URL:http://wrap.warwick.ac.uk/81857 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. AbstractThe effect of periodic changes in particle velocity on mass transfer to the reacting surface of a magnetic particle with a diameter 225 m in laminar flow has been investigated in a microfluidic reactor. The periodic particle motion in a fluid was investigated under a sinusoidal magnetic field generated by a quadrupole arrangement of electromagnets around the reactor. The effect of operating frequency of the rotating magnetic field, intensity of the magnetic field, and phase shift between the two sets of magnets on particle dynamics has been studied. Three particle motion modes have been observed depending on the frequency of the applied field. The mass transfer rate was estimated under steady velocity and variable velocity of the particle using a mass transfer correlation by Feng and Michaelides (Int. J. Heat Mass Transfer 44 (2001) 4445). The validity of this correlation for the case of variable particle velocity has been confirmed with a 2D numerical model, describing actual hydrodynamics and mass transfer towards the particle surface. The mass transfer coefficient *Revised Manuscript (clean for typesetting) Click here to view linked References 2 depends both on the mean particle velocity and the deviation of velocity from the mean value.The periodic movement with variable particle velocity reduces the mass transfer coefficient by 7.6% as compared to steady state motion with the same mean velocity.

show abstract

Using Feedback Control of Microflows to Independently Steer Multiple Particles

Cited by 98 publications

References 38 publications

Fluctuations in closed-loop fluorescent particle tracking

Fluctuations in closed-loop fluorescent particle tracking

Principal-components analysis of shape fluctuations of single DNA molecules

Magnetic actuation of catalytic microparticles for the enhancement of mass transfer rate in a flow reactor

Contact Info

Product

Resources

About