Issue 21, 2012

On-chip latex agglutination immunoassay readout by electrochemical impedance spectroscopy

Abstract

We describe a new class of impedance-based lab-on-chip immunosensors in which the immunoagglutination of latex is monitored by electrochemical impedance spectroscopy (EIS). Antibody-coated latex microspheres agglutinated in the presence of target antigens are precipitated from solution between interdigitated microsized electrodes on a chip. Impedance spectra are reproducibly measured in the 0.1–1 MHz frequency range within several minutes and are shown to be dependent on the aggregate morphology and the sedimentation rates of the agglutinated particles. An equivalent circuit model of the system suggests that the impedance is governed primarily by the electric double layer interactions close to the electrode surface. The effects of sedimentation time, particle type, particle size, and concentration are characterized. The readout method holds promise for developing sensitive miniaturized sensors for rapid immunotesting.

Graphical abstract: On-chip latex agglutination immunoassay readout by electrochemical impedance spectroscopy

Supplementary files

Article information

Article type
Paper
Submitted
05 Feb 2012
Accepted
18 Jul 2012
First published
18 Jul 2012

Lab Chip, 2012,12, 4279-4286

On-chip latex agglutination immunoassay readout by electrochemical impedance spectroscopy

S. Gupta, P. K. Kilpatrick, E. Melvin and O. D. Velev, Lab Chip, 2012, 12, 4279 DOI: 10.1039/C2LC40127D

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