Study On SPR Glucose Sensor Based On Mesoporous Silica

Glucose sensitive membrane is composed of sensitive material,inorganic carrier materials and organic inbedding materials,is one of key factors affecting the performance of an optical glucose sensor.Therefore,it is an important work to research and prepare glucose sensitive membrane with good performance.In this paper,by choosing glucose oxidase with specific catalytic function to glucose molecules as sensitive material,and matrix material having good biological compatibility as inbedding material,mesoporous silica foams（MCF）with large pore size,three-dimensional thermal stability as the matrix material of immobilized enzyme has been prepared.A series of studies in this paper has an important value for the preparation of optical glucose sensor which has wide detection range,high sensitivity and high stability.The main work of this paper is in the following:（1）The mesocellular silica foams with three-dimensional mesoporous foam was prepared,which is characterized by TEM,XRD and FTIR.Glucose oxidase（GOD）was immobilized on the MCF,the optical immobilization conditions were achieved with APTES concentration of 2.5%vol,EDC&NHS concentration of0.15 M&0.0375 M,GOD concentration of 4 mg/mL and pH of 6.5.The GOD/MCF nanoparticles showed maximal catalytic activity at pH 7.0 and 50℃.The thermal,storage and operational stability of GOD were improved greatly after its immobilization.（2）The GOD/MCF was coated by PAM gel to form nanocomposite glucose sensitive materials.Then XRD and FTIR were used to characterize their features.For the prism SPR sensor system,the resonance angle of sensing system under different glucose concentration has been detected and the effect of reactants and sample pH value and other factors on the sensitivity of the sensor has been investigated.The results show that when the content of APTES is 2.5%vol,the content of EDC&NHS is 0.15 M&0.0375 M,the content of GOD is 4 mg/mL,the solution pH is 7.0 and the content of GOD/MCF is 20 mg/dL,the sensitivity of the sensor is up to 0.013 degree/（mg/dL）,and when the glucose concentration is in the range of 0-160 mg/dL,the resonance angle of the sensor has a good linear relationship with glucose concentration.（3）The GOD/SiO₂NP@PAM sensitive membrane was prepared by using SiO₂nanospheres.The results show that when the glucose concentration is in the range of0-80 mg/dL,the resonance angle of the sensor has a good linear relationship with glucose concentration for the sensing chip prepared by GOD/SiO₂NP@PAM sensitive membrane.GOD/SiMCF@CA sensitive membrane was prepared by cellulose acetate（CA）.The results show that 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 glucose concentration,and the sensitivity of the sensor is 0.026degree/（mg/dL）.