We have developed a microfabricated biochip that enumerates CD4+ T lymphocytes from leukocyte populations obtained from human blood samples using electrical impedance sensing and immunoaffinity chromatography. T cell counts are found by obtaining the difference between the number of leukocytes before and after depleting CD4+ T cells with immobilized antibodies in a capture chamber. This differential counting technique has been validated to analyze physiological concentrations of leukocytes with an accuracy of ∼9 cells per L by passivating the capture chamber with bovine serum albumin. In addition, the counter provided T cell counts which correlated closely with an optical control (R2 = 0.997) for CD4 cell concentrations ranging from approximately 100 to 700 cells per L. We believe that this approach can be a promising method for bringing quantitative HIV/AIDS diagnostics to resource-poor regions in the world.

Original languageEnglish (US)
Pages (from-to)1437-1447
Number of pages11
JournalLab on a chip
Issue number8
StatePublished - Apr 21 2011

ASJC Scopus subject areas

  • Bioengineering
  • Biochemistry
  • General Chemistry
  • Biomedical Engineering


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