Molecular interferometric imaging for biosensor applications

Published in:

Ieee Journal of Selected Topics in Quantum Electronics 13,6 (2007) 1680-1690;


Molecular interferometric imaging (MI2) is a common-path interferometric imaging technique for detecting protein binding to surfaces. The experimental metrology limit is 10 pm/pixel longitudinal resolution at 0.4-mu m diffraction-limited lateral resolution, corresponding to 1.7 attogram of protein, which is only 8 antibody molecules per pixel, near to single-molecule detection. The scaling mass sensitivity at the metrology limit is 5 fg/mm. We demonstrate a protein microarray application in a 128-multiplex immunoassay. Assay applications include prostate specific antigen (PSA) at a detection limit of 60 pg/mL and the cytokine interieukin-5 (IL-5) at a detection limit of 50 pg/mL. Real-time binding assays using MI2 enable the study of reaction kinetics of antibodies exposed to antigen, and the binding of antibody Fc regions to protein G.


biomedical optics;; biosensor;; immunoassay;; interferometry;; label-free;; protein microarray;; Engineering, Electrical & Electronic;; Optics

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