Evanescent imaging ellipsometry based microarray readers

Srivatsa Venkatasubbarao, Neil Beaudry, Yanming Zhao, Russell Chipman

Research output: Contribution to journalConference articlepeer-review


Microarrays are being widely used in genomic, proteomic, and diagnostic applications. The binding events to the microarrays are measured with fluorescent labels. Fluorescent microarray readers offer high sensitivity and normalization of the reference and test samples. The use of labels increases the number of steps involved in array testing, concerns about storage labels, and cost of additional labeling steps. This paper describes an alternative approach that does not require the use of fluorescent or other labels. The binding events on the microarray introduce changes in polarization of the illuminated light which is measured to determine the concentrations of biomolecules bound to the microarray. Oligonucleotide microarrays were synthesized and tested on the imaging microarray reader. The refractive index changes of 0.006 and changes in thickness of 1 nm are demonstrated at a spatial resolution of 20 μm over a field of view of 1 cm 2. This ellipsometric technique offers an attractive alternative to fluorescence-based measurement and could be very valuable in some of the genomic, proteomic, diagnostic, and sensing applications.

Original languageEnglish (US)
Article number26
Pages (from-to)1-12
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2004
EventAdvanced Environmental, Chemical, and Biological Sensing Technologies II - Philadelphia, PA, United States
Duration: Oct 25 2004Oct 26 2004


  • Diagnostics
  • Fluorescence
  • Labelless
  • Polarization
  • Retardance
  • Sensors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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