Label-free optical detection of molecular interactions by molecular interferometric imaging

Ming Zhao, Xuefeng Wang, Davi D.D. Nolte

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


Molecular interferometric imaging (MI2) is a label-free optical biosensor that combines common-path interferometry with shot-noise limited characteristics of a CCD array detector to detect protein binding to surfaces. In the metrology limit, it has achieved roughness-limited surface height resolution of 15 pm per 0.4 micron pixel, corresponding to a scaling mass sensitivity of 7 fg/mm, and a molecular resolution of about 15 IgG molecules per pixel. We have applied MI2 to detect cytokine interleukin-5 at a concentration detection limit of 50 pg/mL with a sandwich immunoassay. Real-time binding assays with MI2 enable the study of reaction kinetics, with a scaling mass sensitivity of 2 pg/mm under 7x magnification. Real-time MI2 measurements of anti-rabbit IgG against rabbit IgG were compared with results from surface plasmon resonance, with identical association rate constants at 5xl03 M-1sec-1.

Original languageEnglish (US)
Title of host publicationMaterials for Optical Sensors in Biomedical Applications
Number of pages6
StatePublished - Dec 1 2008
Event2008 MRS Fall Meeting - Boston, MA, United States
Duration: Dec 1 2008Dec 5 2008

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2008 MRS Fall Meeting
Country/TerritoryUnited States
CityBoston, MA

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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