Research Of Fast Wavelength Interrogation Imaging SPR Biosensor

Surface Plasmon Resonance(surface plasmon resonance, SPR) sensing technology attracted increasing attention in the field of biological research. It has a broad application prospect in drug discovery, biochemical monitoring, environmental monitoring and food security and other fields, because of its label-free, high temporal resolution, non-invasive, high sensitivity, no background noise, etc. The principle of SPR technique is the incident wave excites surface plasma waves, the energy of the incident beam(p polarized light) will be transferred to the surface plasmon wave when the evanescent wave vector is equal to surface plasmon wave vector,as causes the change of the energy and the phase of p-wave. Therefore, small changes of the refractive index on the surface of the gold film were obtained with the intensity and the phase of reflected light. Then, characteristic information of sample is achieved.We propose a rapid imaging SPR technique based on spectral imaging methods in this paper. Wavelength scanning period can be reduced to within 1s by combining wavelength modulation technology and feedback algorithm. The intensity information of interest region by CCD is acquired within the wavelength scanning range. The data graph was built through the intensity information at different wavelengths. After the data fitting, the lowest point of curve is considered to the resonance wavelength of sample. When the concentration of the sample changes, it will lead to the change of refractive index on gold surface, and cause the change of the resonance wavelength. The dynamic changes of resonance wavelength will be detected quickly and automatically by fast wavelength scanning through the feedback algorithm. The feedback algorithm was applied into the wavelength scanning SPR imaging system, which improve the time resolution without compromising the sensitivity of our system.We measured the SPR ladder curves at different concentration NaCl solution based on our rapid spectral interrogation SPR imaging system, we get the sensitivity of our instrument is 3.869X10-5RIU, dynamic range 0.004625 RIU. The feasibility of our system for monitoring of protein specific binding reactions is demenstrated. The above experiment shows that the system has a good prospect in biological detections.