Oblique-Incidence Reflectivity Difference Microscope for Label-Free High-Throughput Detection of Biochemical Reactions in Microarray Format

摘要

We recently developed an 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 PCSA scheme and under the off-null condition, a polarization-modulated OI-RD microscope is inherently more sensitive by at least one order of magnitude to thickness changes on a solid surface. Compared to 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; (3) easily covers a field of view as large as the entire surface of a 1” × 3” microscope slide.