摘要
将Fe3O4纳米粒子吸附于涂有壳聚糖（CH）膜的铟锡氧化物导电玻璃（ITO）上,获得Fe3O4纳米粒子-壳聚糖膜修饰电极,再将脲酶（Ur）和谷氨酸脱氢酶（GLDH）通过静电吸附固定在复合物膜上制备了尿素传感器。运用红外光谱、电子显微镜对传感膜的结构进行了表征;以制备的双酶电极为工作电极,采用微分脉冲伏安法研究了酶电极对尿素的响应,结果表明Ur-GLDH/CH-Fe3O4/ITO生物电极的峰电流对尿素非常敏感,尿素的质量浓度与峰电流分别在5-40 mg/L和60-100 mg/L范围内呈线性相关,检出限为0.5 mg/L。固定酶的米氏常数Km为0.56 mmol/L,该值较小,表明混合酶（Ur-GLDH）和尿素具有较好的亲和性。在CH-Fe3O4膜中,Fe3O4纳米粒子的引入增加了壳聚糖膜的表面积,增强了电极的电子传递;CH具有生物相容性,有利于保持生物酶活性。
An amperometric urea sensor was developed by immobilizing urease （Ur） and glutamate dehydrogenase （GLDH） on the superparamegnatic iron oxide （ Fe3 On ） nanoparticles - chitosan （CH） - based film deposited onto indium - tin - oxide （ITO） coated glass plate electrodes via physical adsorption. The properties of the nanobiocomposite film were investigated with infrared absorption spectrometry（IR） and scanning electron microscope（SEM）. The electrochemical performance of the enzyme -based biosensors was evaluated using differential pulse voltammetry （DPV）. The results indicate that Ur- GLDH/CH- Fe304/ITO bioelectrode was sensitive for urea, and a good linearity was obtained between peak current and urea concentration in the range of 5 -40 mg/L and 60 -100 mg/L with a detection limit of 0. 5 mg/L. A low value of Michaelis - Menten constant （Km ） of 0. 56 mmol/L was obtained, which showed a high affinity of enzyme mixture （ Ur - GLDH） for urea. Therefore, the presence of Fe3O4 nanoparticles could result in the increasing of active surface area of CH in the CH -Fe3O4 nanobiocomposite for immobilization of enzymes（ Ur and GLDH）, enhancement of electron transfer and improving of shelf - life of bioelectrode.
出处
《分析测试学报》
CAS
CSCD
北大核心
2009年第10期1165-1169,共5页
Journal of Instrumental Analysis
基金
湖南省科技计划资助项目(2008SK3052
2009CK3069)
湖南省教育厅青年基金资助项目(08B04)
