Detection of HIV-1 p24 Gag in plasma by a nanoparticle-based bio-barcode-amplification method

Eun Young Kim, Jennifer Stanton, Bette T.M. Korber, Kendall Krebs, Derek Bogdan, Kevin Kunstman, Samuel Wu, John P. Phair, Chad A. Mirkin, Steven M. Wolinsky*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


Background: Detection of HIV-1 in patients is limited by the sensitivity and selectivity of available tests. The nanotechnology-based bio-barcode-amplification method offers an innovative approach to detect specific HIV-1 antigens from diverse HIV-1 subtypes. We evaluated the efficacy of this protein-detection method in detecting HIV-1 in men enrolled in the Chicago component of the Multicenter AIDS Cohort Study (MACS). Methods: The method relies on magnetic microparticles with antibodies that specifically bind the HIV-1 p24 Gag protein and nanoparticles that are encoded with DNA and antibodies that can sandwich the target protein captured by the microparticle-bound antibodies. The aggregate sandwich structures are magnetically separated from solution, and treated to remove the conjugated barcode DNA. The DNA barcodes (hundreds per target) were identified by a nanoparticle-based detection method that does not rely on PCR. Results: Of 112 plasma samples from HIV-1 -infected subjects, 111 were positive for HIV-1 p24 Gag protein (range: 0.11-71.5 ng/ml of plasma) by the bio-barcode-amplification method. HIV-1 p24 Gag protein was detected in only 23 out of 112 men by the conventional ELISA. A total of 34 uninfected subjects were negative by both tests. Thus, the specificity of the bio-barcode-amplification method was 100% and the sensitivity 99%. The bio-barcode-amplification method detected HIV-1 p24 Gag protein in plasma from all study subjects with less than 200 CD4+ T cells/μl of plasma (100%) and 19 out of 20 (95%) HIV-1 -infected men who had less than 50 copies/ml of plasma of HIV-1 RNA. In a separate group of 60 diverse international isolates, representative of clades A, B, C and D and circulating recombinant forms CRF01Æ and CRF02_AG, the bio-barcode-amplification method identified the presence of virus correctly. Conclusions: The bio-barcode-amplification method was superior to the conventional ELISA assay for the detection of HIV-1 p24 Gag protein in plasma with a breadth of coverage for diverse HIV-1 subtypes. Because the bio-barcode-amplification method does not require enzymatic amplification, this method could be translated into a robust point-of-care test.

Original languageEnglish (US)
Pages (from-to)293-303
Number of pages11
Issue number3
StatePublished - Jun 2008


  • Bio-barcode-amplification method
  • HIV-1
  • Major core protein of HIV-1 (p24 Gag)

ASJC Scopus subject areas

  • Bioengineering
  • Medicine (miscellaneous)
  • Biomedical Engineering
  • Materials Science(all)


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