Research On Composite Layer Based Surface Plasmon Resonance Sensing Technique And Its Biosensing Application

Surface plasmon resonance(SPR)is a label-free optical sensing technique with high sensitivity.The SPR sensors permit real-time analysis of molecular interaction between ligand and analyte,which have been widely used in the scientific researches and practical applications.The refractive index resolution is the key characteristic of SPR sensors.In this dissertation,we propose a resolution enhancement approach based on the resonance curve regulation using composition layer,and the performance estimation function for the quantitative performance evaluation of the composition layer based SPR sensors.Based on this method,the SPR sensors using the wave-vector regulation and composition waveguide dielectric layer are designed,and the experimental results indicate that both the composition layer based SPR sensors own higher resolution compared with the conventional SPR sensor with single metallic film,and good application prospect owing to the system compatibility with common SPR sensors.As a sensitive analytical tool,the effect of background fluctuations on the SPR sensing characteristics should be suppressed for robust measurement.The temperature fluctuations have significant deteriorating effects on the measurement accuracy of SPR sensors.In this dissertation,a temperature regulation technique is developed based on thermal circulation principle.The water temperature measurments and thermodynamic process analysis are performed to demonstrate the feasibility of this proposed technique experimentally.The SPR sensors are mainly applied for biomolecular interaction analysis currently.In this application,the surface of SPR sensor chip is usually modified to be conjugated with the probe molecules.In this dissertation,we propose a solution circulation based surface modification method.Then the molecular interaction between human immunoglobulin G and protein A is monitored to demonstrate the feasibility of this surface modification method.Finally,this method is used in the biosensing applications of composition layer based SPR sensors and conventional SPR sensors with single metallic film,and the experimental results indicate that the composition layer based SPR sensors can achieve higher signal-to-noise ratio measuring the molecular dynamic process of specific absorption between the protein A and human immunoglobulin G.