Height resolution of antibody spots measured by spinning-disk interferometry on the BioCD

Kevin O'Brien, Ming Zhao, David Nolte

Research output: Contribution to journalArticle


Spinning-disc interferometry (SDI) is a high-speed laser scanning approach to surface metrology that uses common-path interferometry to measure protein spots on a BioCD disk. The measurement sensitivity depends on the scanning pitch and on the time-base. Based on high-resolution laser scanning images of printed antibody spots, we quantify the protein sensitivity as a function of the scan parameters. For smoothly printed antibody spots scanned with a transverse spatial resolution of 1 μm, the surface height precision for a single 100 μm diameter protein spot is approximately 1 pm. This detection sensitivity sets the fundamental limit of detection for label-free BioCD biosensors performing immunoassays.

Original languageEnglish (US)
Article number31
Issue number2
Publication statusPublished - 2016
Externally publishedYes



  • Common-path interferometry
  • Differential phase contrast
  • Molecular interferometry
  • Protein immobilization
  • Silicon metrology

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Mechanical Engineering

Cite this