Scaling mass sensitivity of the BioCD at 0.25 pg/mm

David D. Nolte, Ming Zhao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations


The BioCD is a class of self-referencing interferometric optical biosensor that measures phase modulation from proteins on a spinning disk. The optical detection of the patterns at high speed yields low noise floors far from 1/f noise. Two scans of a disk before and after a 20 hour buffer wash are differenced yielding an rms surface height measurement error of 45 pm corresponding to 5 femtograms of protein within a focal spot diameter. Simple area scaling relations are derived that predict the performance of immunoassays as a function of well area. The scaling mass sensitivity of the BioCD is determined to be 0.25 pg/mm under the conditions of an assay, with a metrology limit of the technique between 0.05 to 0.1 pg/mm. The BioCD sensitivity is equivalent to the best reported surface mass sensitivity of surface plasmon resonance sensors, and is achieved without resonant structures and hence is easy to fabricate and operate.

Original languageEnglish (US)
Title of host publicationSmart Medical and Biomedical Sensor Technology IV
StatePublished - Dec 1 2006
EventSmart Medical and Biomedical Sensor Technology IV - Boston, MA, United States
Duration: Oct 3 2006Oct 4 2006

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherSmart Medical and Biomedical Sensor Technology IV
Country/TerritoryUnited States
CityBoston, MA


  • Area scaling
  • BioCD
  • Common-path interferometer
  • Immunoassay
  • Interferometry
  • Optical biosensor
  • SPR
  • Surface metrology
  • Surface sensitivity

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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