Biomolecular interaction detection based on SPR interferometric imaging

Proteomics research and medical development require high-throughput, sensitive, label-free and real time detection techniques. A biomolecular interaction detection method was developed based on surface plasmon resonance (SPR) interferometric imaging. Phase differences of 90° or -90° were added between the p- and s-polarized components of the incident light to acquire two interferometric images. The signal distribution which gives the refractive index distribution can be calculated from the two interferometric images. The process is repeated to measure variations of the refractive index of biomolecular interaction sensing spots with time. This method is not affected by non-uniform light distributions and power drift and is very sensitive. Experiments demonstrate that the distributions calculated with this method are consistent with a refractive index resolution of about 2×10 -6 RIU (refractive index unit) and a dynamic range of over 0.005 RIU. Rabbit IgG and goat-anti-rabbit IgG interaction detection experiments demonstrate that this method is suitable for high-throughput detection.