Surface Measurement Related on Surface Pasmon Resonance Sensing

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A surface plasmon resonance (SPR) sensor is a useful analytical device that can measure a surface reaction between an analyte and a sensor chip using a gold thin film. Our research purpose is to develop practically useful SPR sensors for wider applications for the analysis of mostly biological samples. For this purpose, highly sensitive measurements are required that can be realized based on the two methods as listed below.1) For realizing high sensitivity in SPR sensor response by physical methods, two new types of SPR sensors were developed.i) Micro-fiber SPR sensor:A germanium-doped optical silica fiber was chemically attached and a thin gold layer of 50nm thickness was placed on the fiber surface by vapor deposition. This micro-SPR sensor can measure down to one picoliter volume sample with reflective index value changes at the 10-3 order level.ii) Slab optical waveguide (SOWG) SPR sensor:Multiple optical reflections are a useful way to reach a highly sensitive detection limit. A5 … More to 10mm SOWG-SPR sensor was made using a glass film as the sensor chip. The sensor chip has a 50nm thin gold layer that can also be used as an electrode for voltammetric measurements. A ferrocene-containing self-assembled monolayer (FC-SAM) was immobilized on the sensor chip surface and the redox reaction was measured by both SPR sensing and voltammetric methods. In this case, real time analysis can be performed to measure redox reactions by both methods. The redox reaction products can be accurately determined with the SPR method.2) Realizing high sensitivity in SPR sensor response by a chemical method:Aconventional commercialized SPR sensor is normally measuring the real part of the reflective index (RI) value. On the other hand, we have clarified the usefulness of measuring the imaginary part of the RI value in the SPR measurement. An absorption-based SPR sensor was prepared relying on the theoretical understanding of the methodology based on imaginary part RI measurements. Consequently, the method was applied to determine low molecular weight substances, such as glucose, which are normally difficult to detect with a conventional SPR sensor. Furthermore, a polymer nanoparticle, which can amplify the SPR response, was prepared as a chemical amplification labeling reagent for a SPR sensor, that is useful for immuno-sensing with high sensitivity Less