A novel surface plasmon resonance imaging interferometry for protein array detection

A novel surface plasmon resonance (SPR) system based on time domain phase modulation interference is presented. The characteristic of the system is that when light is reflected from the sensing surface and passes through the electro-optical crystal controlled by modulation controller, the phase difference between p- and s-polarized components of the reflected light is modulated to form interference. Synchronizing phase modulation and signal acquisition and using Stoilov algorithm to process data, phase change of the reflected light caused by refractive index variation in each sensing unit can be obtained. It is a complete common-light path detection method that can restrain light noise and improve detection sensitivity. Utilizing the experimental device constructed in this detection method, detection of NaCl solution experiments and biomolecular interaction experiments was performed. Experimental results and analysis show that a resolution higher than 10−6 refractive index unit (RIU) is expected to be achieved, and one single CCD pixel enables sensing a detection unit. To reduce noises, 2 × 2 or 3 × 3 pixels can be used to detect one detection unit and high throughput can also be achieved easily. Thus, time domain phase modulation interferometry is potential to be applied in diagnosis, drug discovery and development.