- 學位論文
加熱式葡萄糖感測電極－訊號增益與去干擾探討
Heating based glucose sensing electrode-studies of signal enhancement and interference exclusion
摘要
本研究主要目的為研發加熱式葡萄糖感測電極，以增大感測訊號暨排除干擾物質之影響。其加熱來源為以聚亞醯胺製成之加熱電熱片。運用電源供應器施加加熱電熱片5 V電壓，以驅使感測電極表面溫升至40 oC，至此加速葡萄糖擴散速率，使電極反應訊號得以倍增。首先，將加熱電熱片與白金片組合成加熱式感測電極。後運用電化學方法聚合普魯士藍於白金電極表面，用以輔助感測電極反應訊號之增強；於葡萄糖氧化酶酵素溶液中添加維生素C氧化酶，藉以降低維生素C對感測訊號之影響；運用葡萄糖氧化酶與維生素C氧化酶之酵素溶液滴覆於中間介質普魯士藍表面，最後覆蓋半透薄膜熱塑性聚氨酯，即完成本研究加熱式葡萄糖感測電極之製備。電極於加熱情形下偵測葡萄糖訊號，其線性範圍為1-25 mM葡萄糖濃度，線性相關係數R2為0.99335；電極偵測極限為0.14 mM葡萄糖濃度。其感測電極於pH值7.5之檢測環境有較大感測電流值；將電極於磷酸鹽緩衝溶液中重複進行量測，感測訊號未見衰減，顯示本研究之電極具有良好之再現性。電極於血清環境偵測時，表面受到蛋白質及其他物質吸附而汙染，於加熱狀態下，反應訊號可達3倍之增益。將感測電極保存於血清環境，並每日進行檢測，其感測訊號隨著天數增加而降低，半衰期為8天。以加熱輔助雖然可以增強其反應訊號，但是如何延長其電極之使用壽命仍然是將來研究之重要課題。由實驗結果證明，本研究成功製備加熱式葡萄糖感測電極，其具有增大感測訊號並降低干擾物質影響之效用。
並列摘要
The purpose of this study is to develop a heating based glucose sensing electrode to increase the sensor signal and to exclude interference. The heated electrode is a combination of a polyimide (PI) film flexible heater and a thin Pt slice. The purpose of the PI film flexible heater is for heating the Pt working electrode. By putting into use 5 V of PI film flexible heater, the temperature of the electrode rose to 40 oC. In the fabrication, Prussian blue (PB) was first electro-deposited on a Pt working electrode. A solution containing glucose oxidase (GOx) and ascorbate oxidase (AOx) was then dropped onto the Pt/PB electrode. The final step for fabricating the heated electrode involved coating the unit with a semi-permeable membrane of thermoplastic polyurethane (TPU). The glucose sensing performance of this heated electrode was excellent. When performing a glucose measurement at an operating potential of +0.5 V, the glucose concentration linear response range was from 1 to 25 mM with a correlation coefficient of 0.99335 under the heating condition. The detection limit was estimated to be 0.14 mM at a signal to noise ratio of 3. In studying the pH effect, the biosensor showed maximum responses at pH 7.5. Amperometric signals at elevated temperatures were stable upon prolonged operation involving repetitive measurements. When performing the detection in a serum environment, the electrode encounters protein adsorption on its surface, which led to biofilm formation or biofouling. By providing the heater with an electric source, the surface temperature of the electrode increased. As a result, signal detection is enhanced up to 300%. According to a study on electrode functional stability, the half-life of a heated electrode is 8 days.