Application Of Long-range Surface Plasmon Resonance Technology In Biological Field

Since the surface plasmon resonance (SPR) phenomenon was recognized, it has been receiving increasing attention continuously. The technique offers several advantages, such as little material, fast response and real time analysis. Although the technology of SPR biosensor has made significant progress, higher resolution for detection of biological molecules is urgently desired. One method to improve the resolution of the SPR biosensor is the application of the multilayer configuration known as long-range surface plasmon resonance (LSPR) biosensor.In this paper, propagation characteristics of surface plasmon wave in the dielectric buffer layer/metal interface is introduced firstly. Further, the long-range surface plasmon wave vector based on three-layer structure is discussed and the excitation structure and excitation condition is described. A four-phase numerical model based on prism couple is generated from Fresnel equation and multilayer reflection.A home-built apparatus based on the Kretschmann configuration was constructed for this study. The SPR biosensor comprises three basic parts, the optical system, the mechanical rotating system and the optical detection system. The entire instrument can detect biological solutions rapidly and achieve line continuous monitoring.The sensor chip of conventional surface plasmon resonance biosensor and long-range surface plasmon resonance biosensor is optimized, respectively. Performance of the LSPR-based biosensor was compared to that of the conventional surface plasmon resonance (CSPR) biosensor in series of experiments.A multilayer sensor chip and sensor set-up supporting LSPR have been prepared. To see whether the LSPR-based biosensor has a better performance, we do series of experiments to detect concentrations of two biological solutions and compared results with those obtained by CSPR- based biosensor. The results show the sensitivity of LSPR-based biosensor was up to 2-fold greater than that of CSPR-based biosensor. Finally, standard curves of two biological solutions are established based on single-layer configuration and multilayer configuration, respectively.