Electrochemical impedance biosensor with electrode pixels for precise counting of CD4+ cells: A microchip for quantitative diagnosis of HIV infection status of AIDS patients

By Jiang, Xingqun & Spencer, Michael G.
Published in Biosensors and Bioelectronics NULL 2010

Abstract

Oriented for the quantitative diagnosis of HIV infection status of AIDS patients, a cell biosensor based on electrochemical impedance spectroscopy has been developed for the precise counting of human CD4+ cells. In this new biosensor, the sensing area was composed of densely packed working electrode pixels, each of which was comparable to a single CD4+ cell in size. CD4+ cells were captured on the chemically modified electrode pixels, and detected individually by monitoring the interfacial impedance changes on each independent pixel. The detection of a single cell was achieved by the “on� and “off� states of electrode pixel, depending on the cell capture status. The cell counting was digitalized by summing the electrode pixels in the “on� state (captured with a single cell). Compared with peer counting methods, the biosensor reported here was featured with a small device dimension, a minimal sample consumption, a finest detection resolution and a highest counting accuracy.

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