Study On Glucose Sensing Film Based On Surface Plasmon Resonance Sensor

One of the key devices in optical glucose sensor is glucose sensitive membrane owing a specific effect on glucose molecules,which is composed of sensitive material with specific catalytic function to glucose molecules and matrix material having good biological compatibility and adsorption properties.In the optical glucose sensor,the physical and chemical properties of glucose sensitive membrane have a direct influence on the performance of optical glucose sensor.Glucose sensitive membrane with good optical properties and adsorption properties,has an important significance for the development of optical glucose sensor which has high sensitivity,wide detection range,short response time,high stability.This paper mainly includes the following aspects:?1?The glucose oxidase?GOD?was immobilized on the surface of SiO₂nanospheres by covalent linkage method to form the immobilized glucose oxidase?GOD/SiO₂?,and then the GOD/SiO₂ was coated by PAM gel to form nanocomposite glucose sensitive materials.Subsequently,the XRD,SEM and FTIR were used to characterize their features.?2?Based on the four-layer model--prism?or optical fiber?/gold film/sensitive membrane/sample,the characteristics of the prism SPR sensing and the terminal reflective optical fiber SPR sensing have been discussed.And the results show that the characteristic parameters of the two SPR sensors,the resonance angle and the resonance wavelength,are in good linear relationship with the refractive index?RI?of the glucose sensitive membrane in a certain range of glucose concentration.?3?For the prism SPR sensor system,the forming method of nanocomposite membrane materials in flat glass gold substrate has been explored,the resonance angle of sensing system under different glucose concentration has been detected and the effect of GOD content and sample pH value and other factors on the sensitivity of the sensor has been investigated.The results show that when the content of GOD is 4 mg/mL and the solution pH is 7.0,the sensitivity of the sensor is up to 0.019degree/?mg/dL?,and when the glucose concentration is in the range of 0-80 mg/dL,the resonance angle of the sensor has a good linear relationship with the RI of the glucose sensitive membrane and glucose concentration.?4?For the terminal reflective optical fiber SPR sensor,the forming method of nanocomposite glucose sensitive materials in optical fiber probe with gold film has been explored,the resonance wavelength of sensing system under different glucose concentrations has been detected and the influence of the thickness,content of GOD,pH value and temperature on the sensitivity of the sensor has been investigated.The results also show that when the glucose concentration is in the range of 0-80 mg/dL,the resonance wavelength of the sensor has a good linear relationship with the RI of the glucose sensitive membrane and glucose concentration and under the optimum conditions,the sensitivity of the optimized fiber optic gold probe reaches 0.13 nm/?mg/dL?.?5?The adsorption isotherm model was used to understand the sensing mechanism of the nanocomposite glucose sensitive membrane.Both of the SPR calculated data show that in the range of 0-80 mg/dL,the concentration of the glucose has a good linear relationship with the volume fraction of the glucose in the glucose sensitive membrane,which can be explained by Freundlich adsorption isotherm model,and when the glucose concentration is more than 120 mg/dL,the Langmuir adsorption isotherm model will be more suitable to describe the adsorption.