Flow sandwich-type immunoassay in microfluidic devices based on negative dielectrophoresis

Microparticles have been manipulated in a microfluidic channel by means of negative dielectrophoresis (n-DEP), and the approach applied to a heterogeneous immunoassay system. A microfluidic device, with three-dimensional (3-D) microelectrodes fabricated on two substrates, was used to manipulate part...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2007-05, Vol.22 (11), p.2730-2736
Main Authors: Yasukawa, Tomoyuki, Suzuki, Masato, Sekiya, Takashi, Shiku, Hitoshi, Matsue, Tomokazu
Format: Article
Language:English
Subjects:
Biological and medical sciences
Biosensing Techniques - instrumentation
Biosensing Techniques - methods
Biotechnology
Dielectrophoresis
Electrophoresis, Microchip - instrumentation
Electrophoresis, Microchip - methods
Equipment Design
Equipment Failure Analysis
Flow Injection Analysis - instrumentation
Flow Injection Analysis - methods
Fluoroimmunoassay - instrumentation
Fluoroimmunoassay - methods
Fundamental and applied biological sciences. Psychology
Immunoglobulin G - analysis
Immunoglobulin G - immunology
Microelectrodes
Microfluidic device
Microparticles
Reproducibility of Results
Sandwich immunoassay
Sensitivity and Specificity
Separation
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Summary:Microparticles have been manipulated in a microfluidic channel by means of negative dielectrophoresis (n-DEP), and the approach applied to a heterogeneous immunoassay system. A microfluidic device, with three-dimensional (3-D) microelectrodes fabricated on two substrates, was used to manipulate particle flow in the channel and to capture the particles in the caged area that was enclosed by the collector electrodes. Polystyrene microparticles (6 μm diameters) modified with anti-mouse immunoglobulin G (IgG) were manipulated and captured in the caged area when surrounded by intense n-DEP electric fields. Specifically, particles were trapped when AC voltages with amplitudes of 6–15 V peak and frequencies over 500 kHz were applied to the two facing microelectrodes. A heterogeneous sandwich immunoassay was achieved by successively injecting a sample solution containing mouse antigen (IgG), and a solution containing a secondary antibody with a signal source (FITC-labeled anti-mouse IgG antibody), into the channel. The fluorescence intensity from captured particles in the caged area increased with increasing concentrations (10 ng/ml to 10 μg/ml) of mouse IgG. The described system enables mouse IgG to be assayed in 40 min. Thus, the automatic separation of free fractions from desired analytes and labeled antibodies can be achieved using a microfluidic device based on n-DEP.
ISSN:0956-5663
1873-4235
DOI:10.1016/j.bios.2006.11.010