尿素酶固载于纳米二氧化钛多孔膜上的尿素生物传感器

A Novel Urea Biosensor Based on the Urease Immobilized on Nanoporous TiO_2 Film

在钛丝基体上沉积一层纳米二氧化钛（TiO2）多孔膜，然后直接将尿素酶吸附在TiO2膜上。基于TiO2膜的pH响应，发展了一种廉价的、易于微型化的pH敏尿素酶传感器。采用石英微天平、红外光谱和紫外可见光谱等手段研究尿素酶在TiO2膜上的物理固载行为。由于纳米TiO2在紫外光下光自洁特性可获得高度洁净的表面，石英微天平研究表明在光自洁后的TiO2膜上尿素酶的吸附具有很好的重复性和稳定性，吸附量为0．22mmol／g，吸附平衡常数k为3．15×10^5L／mol。采用电位法测定了尿素酶／TiO2复合膜电极的性能及其影响因素，在1．0mmol／LpH7-8PBS，35℃，尿素的响应范围为8．5×10^-5-1．5×10^-1mol／L，相关系数r为0．9937，检出限为6×10^-5moL／L。

Based on the pH response of the urease immobilized on the nanoporous TiO2 film, a cheap and miniaturized urease biosensor for urea was developed, The physical immobilization behavior of urease on the TiO2 film was investigated by quartz crystal microbalance（QCM） , FT- IR and UV spectrophotometers, The QCM results showed that the urease adsorbed on the photo self-cleaning nanoporous TiO2 film was very stable and reproducible, The amount adsorbed was O. 22 mmol/g and the adsorption equilibrium constant was 3, 15 × 10^5 L/mol. The performance of the urease/TiO2 electrode and the influencing factors were measured by potentiometry. Under optimum condition, the linear range of the response for urea was 8, 5× 10^-5 - 1.5 ×10^-1 mol/L with a correlation coefficient of 0, 993 7 and a detection limit of 6× 10^-5 mol/L.