Area-scaling of interferometric and fluorescent detection of protein on antibody microarrays

Xuefeng Wang, Ming Zhao, David D. Nolte

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The sensitivity limits for an in-line interferometric (IL)/fluorescent (FL) dual-channel BioCD are established as a function of spatial averaging. Forward-phase and sandwich assays at 10 ng/ml were performed on large-scale antibody microarrays (6800-spot) and detected using in-line interferometry and fluorescence channels. The interferometric channel has an extrapolated label-free limit-of-detection (LOD) of 250 pg/ml in a forward-phase assay for which the fluorescent channel is inapplicable. In the sandwich assay, the extrapolated limit-of-detection is 70 pg/ml for the interferometric channel, and for the fluorescent channel it is 30 pg/ml. Intrinsic scale-free sensitivities for the detection channels are defined assuming spatially uncorrelated fluctuations with sensitivities of S′ = 13 pg/mm for interferometric detection and 7 pg/mm for sandwich fluorescent detection. The intrinsic sensitivities become weakly scale dependent in the presence of fractal spatial correlations among the antibody spots.

Original languageEnglish (US)
Pages (from-to)981-987
Number of pages7
JournalBiosensors and Bioelectronics
Volume24
Issue number4
DOIs
StatePublished - Dec 1 2008

Keywords

  • Antibody microarray
  • BioCD
  • Fluorescence
  • Immunoassay
  • Interferometry
  • Label-free
  • Scalability

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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