title: Oblique-incidence reflectivity difference microscope for label-free high-throughput detection of biochemical reactions in a microarray format.
abstract: We describe a recently developed oblique-incidence reflectivity difference (OI-RD) microscope, a form of polarization-modulated imaging ellipsometer, for label-free-high-throughput detection of biomolecular reactions on DNA and protein microarrays. We present examples of application of this technique to end-point and real-time investigations of DNA-DNA hybridization, antibody-antigen capture, and protein-small-molecule binding reactions. Compared to a conventional imaging ellipsometer based on the polarizer-compensator-sample-analyzer scheme and under the off-null condition, a polarization-modulated OI-RD microscope is inherently more sensitive by at least 1 order of magnitude to thickness changes on a solid surface. Compared with imaging surface plasmon resonance microscopes based on reflectance change on falling or rising slopes of the surface plasmon resonance, the OI-RD microscope (1) has a comparable sensitivity, (2) is applicable to conventional microscope glass slides, and (3) easily covers a field of view as large as the entire surface of a 1 in. x 3 in. (2.54 cm x 7.62 cm) microscope slide.
authors.affiliation: Department of Physics, University of California, CA 95616, USA. xdzhu@physics.ucdavis.edu
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Zhu
authors.forename: James P
authors.initials: JP
authors.lastname: Landry
authors.forename: Yung-Shin
authors.initials: YS
authors.lastname: Sun
authors.forename: Jeff P
authors.initials: JP
authors.lastname: Gregg
authors.forename: Kit S
authors.initials: KS
authors.lastname: Lam
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Guo
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D046228:Microarray Analysis / Q000295:instrumentation* / Q000379:methods; D008859:Microscopy, Polarization / Q000295:instrumentation* / Q000379:methods; D010783:Photometry / Q000295:instrumentation* / Q000379:methods; D012680:Sensitivity and Specificity; D013194:Staining and Labeling