葡萄糖氧化酶在氧化铋纳米多晶膜中的固定及生物传感

Immobilization and biosensing of glucose oxidase in bismuth oxide nanoparticles polycrystalline films

以实验室合成的纳米氧化铋(BiOx)为载体,经戊二醛交联,将葡萄糖氧化酶(GOD)固定于铂盘电极表面,从而构筑新型葡萄糖生物传感器.所得修饰电极利用扫描电镜(SEM)、红外光谱(IR)和电化学交流阻抗(EIS)等方法进行了详细表征.扫描电镜显示纳米氧化铋由大量具有二维片状纳米结构和一维纳米线组成;氧化铋纳米片厚度为80～110nm,并具有亚微米和微米级别的横向尺寸;氧化铋纳米棒、线的直径约为40～50nm.实验结果表明,构筑传感器的最佳条件为:GOD与BiOx的质量比为2∶1,酶固载量为30μg.同时还考察了溶液pH以及操作电位对传感器响应电流的影响.该传感器在0.5V(vs.SCE)电位下检测葡萄糖,线性范围为1×10-3～1.5mmol/L,检出限为0.4μmol/L(信噪比为3),酶催化反应的表观米氏常数为2.88mmol/L.同时该传感器还表现出响应迅速(5s)?重现性好、使用寿命长等优点.

A novel glucose biosensor was achieved by casting the biocomposite on the surface of platinum disk electrode via the cross-linking step by glutaraldehyde,with the laboratory-prepared bismuth oxide nanoparticles as enzyme immobilization matrix.The modified electrode has been characterized by scanning electron microscopy（SEM）,infrared spectroscopy（IR） and electrochemical impedance（EIS） etc.SEM shows that the prepared nano-bismuth oxide is composed by two-dimensional nano-bismuth oxide sheet and one-dimensional nano-rod.The nano-bismuth oxide sheet thickness is about 80 to 110 nm with sub-micron-micron-level horizontal dimensions,and the diameter of bismuth oxide nanorods is about 40 to 50 nm.Experimental results show that the optimal conditions to fabricate biosensor are： GOD and BiOx mass ratio of 2∶1,enzyme immobilized amount of 30 μg.The pH and the detection potential effects were also investigated.The biosensor has a wide linear range from 1×10-3 to 1.5 mmol/L with detection limit of 0.4 mmol/L（SNR=3） at 0.5 V vs.SCE.The apparent Michaelis constant is 2.88 mmol/L.And the biosensor presents fast response（5 s）,good repeatability and excellent long-term stability.