A new palm-sized surface plasmon resonance (SPR) biosensor based on modulation of a light source by a rotating mirror

A novel surface plasmon resonance (SPR) sensing scheme was devised to develop a palm-sized SPR biosensor device. In this system, the beam from a diode laser (as the incident light source) is modulated using a rotating mirror. The reflected light from the gold chip is then captured using a CMOS image sensor, controlled by a notebook PC via a USB interface This provides a portable POCT SPR sensor device which enables label-free and real-time analyses This method can also eliminate the deterioration in image quality of the reflected laser light, originating from the coherency of the laser source. The sensing response of the system to the bulk refractive index was calibrated using various concentrations of glycerol solution As a result, the SPR sensor was able to detect a similar to 2 5 x 10(-6) RIU change in the refractive index of the solution without implementing any of data processing techniques The performance of the sensor was tested by monitoring the binding of PSA to its antibody in real-time to verify its potential applicability in analyzing biomolecular interactions The results obtained from a series of tests confirmed the practicality of the sensor for the on-site detection of a variety of substances in biology, diagnosis, the environment, and defense. (C) 2010 Elsevier B.V. All rights reserved