Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10430097 | Biosensors and Bioelectronics | 2005 | 9 Pages |
Abstract
The current study was undertaken to fabricate a small micro-electrode on-chip to rapidly detect and quantify human CD4+ cells in a minimal volume of blood through impedance measurements made with simple electronics that could be battery operated implemented in a hand held device. The micro-electrode surface was non-covalently modified sequentially by incubation with solutions of protein Gâ², human albumin, monoclonal mouse anti-human CD4, and mouse IgG. The anti-human CD4 antibody served as the recognition and capture molecule for CD4+ cells present in human blood. The binding of these biomolecules to the micro-electrodes was verified by impedance and cyclic voltammetry measurements. An increase in impedance was detected for each layer of protein adsorbed onto the micro-electrode surface. This process was shown to be highly repeatable. Increased impedance was measured when CD4+ cells were captured on the micro-electrode, and the impedance also increased as the number of captured cells increased. Fluorescence microscopy of captured cells immunolabeled with anti-human CD4, CD8, and CD19 antibodies, and the nuclear label DAPI, confirmed that only CD4+ cells were captured. The results were highly dependent on the specimen preparation method used. We conclude that the on-chip capture system can efficiently quantify the number of CD4+ cells.
Related Topics
Physical Sciences and Engineering
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Authors
Nirankar N. Mishra, Scott Retterer, Thomas J. Zieziulewicz, Michael Isaacson, Donald Szarowski, Donald E. Mousseau, David A. Lawrence, James N. Turner,