Dry-Type Glucose Sensor Using MOS Structure with GOD+BSA as The Sensing Layer

• Main Authors: Bei-Rong Chang, 張倍榮
• Other Authors: Dr.You-Lin Wu
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/78906552179398000361

碩士 === 國立暨南國際大學 === 生物醫學科技研究所 === 93 === ABSTRACT This thesis is based on the MOSC using the mixed BSA (Albumin serum Bovine ) and GOD(Glucose Oxidase) to be a sensitive layer and cross-linking the oxidase layer by using the immobilization technique to product a dry Glucose sensor. We measured different concentration of Glucose solution and used the MOSC characteristic, I-V and Low Frequency C-V respectively, to research different Glucose concentration measurements. According to experiment results, in the I-V measurement of different Glucose concentration, sensitivities of the sensitive layer are 0.72PA/M and 0.8PA/M respectively in the condition of Vg=+4V and Vg=+5V when we titrate the solution 20 minis later. Otherwise, we also found that if we increased the concentration of the Glucose solution, its amount of the current shift would become greater. This maybe the higher concentration of Glucose solution has more Hydrogen ion concentration and these Hydrogen ions adsorb on the interface of the SiO2 sensitive layer to increase the shift amount. We could get similar results in the C-V measurement. When titrated Glucose solution make the surface of SiO2 sensitive layer get more Hydrogen ions absorption and this situation would make the Low-Frequency C-V curve shift to the left. This thesis experiments appeared that C-V curves with different Glucose concentration were order in displays. Because the C-V curve exhibitions are phenomena of shift into the negative voltage, we think that those Hydrogen ions , reacting through the enzyme layer, adsorbing on the SiO2 sensitive film is a major reason. We could calculate from its Flat-Band voltage variations and mole concentration that the approximate sensitivity of the sensor is 1.074V/M. Owing to experiment data of high Glucose concentration (0.5M-2M) we could find the sensor was available and stable for measuring Glucose. So we further measured low Glucose concentration range which was below 0.5M. We clearly observed that different Glucose concentration would cause Flat-Band variations indeed. We could calculate from the Flat-Band voltage and mole concentration that the sensitivity was 34.4mV/100mM under low Glucose concentration. According the experiment data we thought this simple MOSC structure with GOD+BSA enzyme layer we proposed could be used to measure different Glucose concentration solution via its I-V and C-V measurement. Although the change amount of I-V was extreme small, it was very regular and arranged in order, and furthermore C-V variations had good response and expressed stably. Comparing with the PH-sensor which was designed by predecessors of our lab, using the GOD+BSA enzyme layer has quite improvement about the part of stability substantially.