Surface plasmon resonance phase-shift interferometry: real-time microarray biomolecular interaction analysis

A novel surface plasmon resonance (SPR) imaging system based on modified Mach-Zehnder phase-shifting interferometry (PSI) measures the spatial phase variation of a resonantly reflected light in biomolecular interaction. In this technique, the SPR DNA microarray can diagnose the target DNA without additional labeling in real-time biomolecular interaction analysis (BIA). Owing to the feasible and swift measurements, the SPR microarray with this SPR imaging system can be extensively applied to the nonspecific adsorption of protein, the membrane-protein interaction, receptor-ligand interaction, DNA hybridization. The detection limitation of the SPR PSI imaging system is improved to about 1 pg/mm 2 surface coverage of biomaterial for each individual spot over that of the conventional SPR imaging system that observe the intensity variation of a resonantly reflected light. The SPR PSI imaging system and its SPR microarray can provide the capability to analyze DNA hybridization or protein interaction in real-time, with high resolution, and at high-throughout screening rates.