Surface plasmon resonance (SPR) phase-shift interferometry, (PSI) is a novel technique which combines SPR and modified Machzehnder PSI to measure the spatial phase variation caused by biomolecular interactions upon a sensing chip. The SPR-PSI imaging system offers high resolution and high-throughout screening capabilities for microarray DNA hybridization without the need for additional labeling, and provides valuable quantitative information. The SPR-PSI imaging system has an enhanced detection limit of 2.5 × 10T7 refraction index change, a long-term phase stability of π/100 in 30 min, and a spatial phase resolution of π/300 with 100×100 μm2 detection area. This study successfully demonstrates the label-free observation of 15-mer DNA microarray.
- DNA hybridization
- Imaging system
- Phase-shifting interferometry
- Surface plasmon resonance