Bead-based immunoassays using a micro-chip flow cytometer

Holmes, David; She, Joseph; Roach, Peter L.; Morgan, Hywel

doi:10.1039/b707507n

Cited by 92 publications

(88 citation statements)

References 34 publications

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“…Focusing original random distributed particles into one or several equilibrium positions can be used to enrich or separate particles according to their different equilibrium positions [1]. Also, focusing of particles along a specific path can be employed in flow cytometry for detection and enumeration of bio-particles [2][3].…”

Section: Introductionmentioning

confidence: 99%

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

Zhang

et al. 2013

J. Micromech. Microeng.

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G. (2013). Inertial focusing in a straight channel with asymmetrical expansion-contraction cavity arrays using two secondary flows. Journal of Micromechanics and Microengineering, 23 (8), 1-13. Inertial focusing in a straight channel with asymmetrical expansioncontraction cavity arrays using two secondary flows AbstractThe focusing of particles has a variety of applications in industry and biomedicine, including wastewater purification, fermentation filtration, and pathogen detection in flow cytometry, etc. In this paper a novel inertial microfluidic device using two secondary flows to focus particles is presented. The geometry of the proposed microfluidic channel is a simple straight channel with asymmetrically patterned triangular expansion-contraction cavity arrays. Three different focusing patterns were observed under different flow conditions: (1) a single focusing streak on the cavity side; (2) double focusing streaks on both sides; (3) half of the particles were focused on the opposite side of the cavity, while the other particles were trapped by a horizontal vortex in the cavity. The focusing performance was studied comprehensively up to flow rates of 700 μl min−1. The focusing mechanism was investigated by analysing the balance of forces between the inertial lift forces and secondary flow drag in the cross section. The influence of particle size and cavity geometry on the focusing performance was also studied. The experimental results showed that more precise focusing could be obtained with large particles, some of which even showed a single-particle focusing streak in the horizontal plane. Meanwhile, the focusing patterns and their working conditions could be adjusted by the geometry of the cavity. This novel inertial microfluidic device could offer a continuous, sheathless, and high-throughput performance, which can be potentially applied to high-speed flow cytometry or the extraction of blood cells. (1) single focusing streak on cavity side; (2) double focusing streaks on both sides; (3) half of particles focused on the opposite side of cavity, and other particles trapped by horizontal vortex in cavity. The focusing performance was studied comprehensively up to the flow rates of 700 µl min -1 . The focusing mechanism was investigated by analyzing force balance between inertial lift forces and secondary flow drag in the cross section.The influence of particle size and cavity geometry on the focusing performance was also studied. Experimental results showed that a more pronounced focusing performance can be obtained with large particles, which even showed a single-particle focusing streak in horizontal plane. Meanwhile, focusing patterns and their working conditions were adjustable by the geometry of cavity. The novel inertial microfluidic device was capable of offering a continuous, sheathless, and high-throughput performance, which can be potentially applied to highspeed flow cytometry or extraction of blood cells.

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Section: Introductionmentioning

confidence: 99%

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

Zhang

et al. 2013

J. Micromech. Microeng.

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“…1-3 Several microfluidic devices have recently been reported for single-cell impedance measurement using coplanar 41,42 and parallel [43][44][45][46][47] facing electrodes. Hydrodynamic trapping methods have been employed in conjunction with -EIS for measuring cellular impedance properties over extended periods of time.…”

Section: Introductionmentioning

confidence: 99%

A microfluidic device for simultaneous electrical and mechanical measurements on single cells

et al. 2011

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This paper presents a microfluidic device for simultaneous mechanical and electrical characterization of single cells. The device performs two types of cellular characterization ͑impedance spectroscopy and micropipette aspiration͒ on a single chip to enable cell electrical and mechanical characterization. To investigate the performance of the device design, electrical and mechanical properties of MC-3T3 osteoblast cells were measured. Based on electrical models, membrane capacitance of MC-3T3 cells was determined to be 3.

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“…All of these devices were meant for counting and possibly sizing purposes. Only with the possibility to vary the impedance measurement frequency, however, was it demonstrated that the microfluidic approach has the potential for cell characterization (18,51,(69)(70)(71).…”

Section: Microfluidic Coulter Systems Sensitivitymentioning

confidence: 99%

Microfluidic impedance‐based flow cytometry

Berardino²,

et al. 2010

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Microfabricated flow cytometers can detect, count, and analyze cells or particles using microfluidics and electronics to give impedance-based characterization. Such systems are being developed to provide simple, low-cost, label-free, and portable solutions for cell analysis. Recent work using microfabricated systems has demonstrated the capability to analyze micro-organisms, erythrocytes, leukocytes, and animal and human cell lines. Multifrequency impedance measurements can give multiparametric, high-content data that can be used to distinguish cell types. New combinations of microfluidic sample handling design and microscale flow phenomena have been used to focus and position cells within the channel for improved sensitivity. Robust designs will enable focusing at high flowrates while reducing requirements for control over multiple sample and sheath flows. Although microfluidic impedance-based flow cytometers have not yet or may never reach the extremely high throughput of conventional flow cytometers, the advantages of portability, simplicity, and ability to analyze single cells in small populations are, nevertheless, where chip-based cytometry can make a large impact. ' 2010International Society for Advancement of Cytometry Key terms microfluidics; impedance characterization; label free; single cell analysis; hydrodynamic focusing; sorting MICROFLUIDIC flow cytometers can bring many advantages to the field of flow cytometry (FCM). Compared to typical flow cytometry channel sizes, the miniaturized dimensions permit microfluidic systems to analyze single cells, to identify cellular variability in gene expression, or drug response within a cell population. Chipbased cytometers can have lower size and costs than conventional benchtop instruments, and may be portable. Today, the developmental aim for microfluidic systems is to reach the same sensitivity and capability for multiparametric analyses as delivered by conventional flow cytometers. Many efforts have been made to improve existing devices and to create new miniaturized high-end instruments. Microfluidic chips can incorporate on-chip cell preparation, cell culture, lysis, and modules for optical, electrophoretic, or genomic analysis (1). They are also suitable for analysis of cells in suspension as well as adherent cells.Miniaturized cytometry devices will have high impact in the development of point-of-care devices in developing countries. Accurate CD4 1 T-cell counts are used to monitor human immunodeficiency virus (HIV)-infected patients, and various thresholds of the number of CD4 1 T lymphocytes per ll of whole blood are used to start antiretroviral therapy (2-5). A simple, single-purpose CD4 cell counting device, which does not require standard laboratory equipment or trained laboratory personnel, could help some of the 33 million HIV-infected people worldwide monitor the stage of infection (6)(7)(8). In this application, increased analysis throughput is a secondary concern compared to increased sensitivity and specificity. Portable, miniatu...

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Bead-based immunoassays using a micro-chip flow cytometer

Cited by 92 publications

References 34 publications

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

A microfluidic device for simultaneous electrical and mechanical measurements on single cells

Microfluidic impedance‐based flow cytometry

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