A novel approach to the automation of clinical chemistry by controlled manipulation of magnetic particles

Ostergaard, Steen; Blankenstein, Gert; Dirac, H.; Leistiko, Otto

doi:10.1016/s0304-8853(98)00572-1

Cited by 41 publications

(21 citation statements)

References 3 publications

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“…A theoretical modeling of the assays shown here suggested that analytes at low concentration (≤ 1 nM) could be detected within seconds if all capture Abs were active and the flow rate of sample in the microchannel kept large enough to prevent depletion of analyte. [277] Strategies to pattern proteins inside microchannels [278] or to engineer binding sites using beads, [279,280] magnetic particles, [281][282][283] thermally responsive polymers, [284] oriented receptors, [285,286] conjugated proteins, [287] or self-assembly [288][289][290] would certainly augment the bioanalytical functionality of microfluidic systems. Table 1 puts the characteristic dimensions of the main functional units of a CS into perspective with the characteristic timescale for diffusion in these units, and it enunciates the number of analyte molecules that can be accommodated in each unit.…”

Section: Low-volume and High-sensitivity Assaysmentioning

confidence: 99%

Microfluidics for Processing Surfaces and Miniaturizing Biological Assays

2005

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This review is an account of our efforts to develop a versatile and flexible microfluidic technology for surface‐processing applications and miniaturizing biological assays. The review is presented in the context of current trends in microfluidic technology and addresses some of the major challenges for confining chemical and biochemical processes on surfaces: the sealing of a microchannel with a surface, the world‐to‐chip interface, the displacement of liquids in small conduits, the sequential delivery of multiple solutions, the accurate patterning of surfaces, the coincident detection of various analytes, and the detection of analytes in a small and dilute sample. Our solutions to these problems include the use of reversible sealing, capillary phenomena for powering and controlling liquid transport, and non‐contact microfluidics for spotting and drawing (on surfaces) with flow conditions. These solutions offer many advantages over conventional techniques for handling minute amounts of liquids and may find applications in lithography, biopatterning (e.g., the patterning of biomolecules), diagnostics, drug discovery, and also cellular assays.

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Section: Low-volume and High-sensitivity Assaysmentioning

confidence: 99%

Microfluidics for Processing Surfaces and Miniaturizing Biological Assays

2005

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“…This explains why, mostly, the large field of (mechanically moving) permanent magnets has been used for the separation, transport, and positioning of the magnetic microbeads (Miltenyi et al 1990). In an approach towards miniaturization and automation of analytical applications, a system has been proposed in which liquid movement is substituted with magnetically induced movement of magnetic particles (Ostergaard et al 1999). Fluidic channels were realized on a plastic cartridge of centimeters in size and the magnetic transport was induced by mechanically moving external permanent magnets.…”

Section: Transport Of Magnetic Beadsmentioning

confidence: 99%

Magnetic bead handling on-chip: new opportunities for analytical applications

Gijs

2004

Microfluid Nanofluid

497

555

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This review describes recent advances in the handling and manipulation of magnetic particles in microfluidic systems. Starting from the properties of magnetic nanoparticles and microparticles, their use in magnetic separation, immuno-assays, magnetic resonance imaging, drug delivery, and hyperthermia is discussed. We then focus on new developments in magnetic manipulation, separation, transport, and detection of magnetic microparticles and nanoparticles in microfluidic systems, pointing out the advantages and prospects of these concepts for future analysis applications.

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“…Envisioned applications of nanoparticles include, but are not limited to, cell labeling, magnetic separation, targeted drug delivery, hyperthermic cell treatment, and MRI contrast enhancement [1]. Significant study has been performed regarding these concepts and is available in references [2], [3], [4], [5]. A second novel application of a magnetically reactive device being introduced to the internal workings of a living body and being manipulated by an applied ex vivo magnetic field is magnetic implant guidance.…”

Section: Introductionmentioning

confidence: 97%

Modeling and Analysis of a Permanently Magnetized Sphere's Motion Facilitated by Field Manipulation

Duvall

Pagilla

Misawa

2006

Proceedings of the 45th IEEE Conference on Decision and Control

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A model describing the motion of a magnetized sphere in a fluid medium subject to an applied field is developed. The inspiration for this system is rooted in technologies and procedures being explored in the biomedical community. In these systems, the accepted approximation of Stokes' flow about the sphere is discussed and limitations to this are identified with drag force relations accounting for wall effects presented. For this system, the sphere is approximated as a point dipole and the resulting electromagnetic force model is presented. For motion of the sphere using static electromagnets, a reduced coil set technique is proposed. The technique consists of utilizing the minimum number of coils for generation of the desired force on the sphere. This approach is in contrast to the existing solutions which use the full coil set for parallel and anti-parallel motion and single out a solution for the underdetermined system. A technique for determining the proper coil combination is developed from examining the definiteness of the geometric field functions. A coil array configuration consisting of a four coil assembly is investigated to facilitate planar motion of a magnetized spherical particle in a fluid medium. For this configuration, the reduced coil set consists of only two adjacent coils being active at any given time. The exact inverse current solution for the minimized coil set is derived and presented. The system dynamic model is formulated and represented in a nonlinear state space system.

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A novel approach to the automation of clinical chemistry by controlled manipulation of magnetic particles

Cited by 41 publications

References 3 publications

Microfluidics for Processing Surfaces and Miniaturizing Biological Assays

Microfluidics for Processing Surfaces and Miniaturizing Biological Assays

Magnetic bead handling on-chip: new opportunities for analytical applications

Modeling and Analysis of a Permanently Magnetized Sphere's Motion Facilitated by Field Manipulation

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