Imaging technique for the screening of protein-protein interactions using scattered light under surface plasmon resonance conditions.

We propose a novel technique to detect protein-protein interactions in microarray format. The technique involves measuring scattered light under surface plasmon resonance (SPR) conditions. We have shown that the maximum scattering angle correlates with the traditionally employed reflection minimum. Panoramic scanning of scattered light under SPR conditions has all the functional advantages of the SPR technique. In addition, the proposed technique simplifies device design, increases the dynamic range of analysis, and integrates data with those from surface-plasmon field-enhanced fluorescence spectroscopy. We demonstrate the technique by showing direct protein-protein interaction between protein A and either rabbit antibodies or human serum.