一次性酶免疫传感电极快速检测福氏志贺氏菌的研究

Rapid Detection of Shigella Flexneri with Multi-Wall Carbon Nanotubes/Chitosan Modified Screen-Printed Electrode

为研究快速检测福氏志贺氏菌的电化学免疫传感电极,将羧基化多壁碳纳米管(MWCNT)与壳聚糖(chitosan)制备成复合物,应用此复合物将辣根过氧化物酶标记的福氏志贺氏菌抗体(HRP-anti-S.flexneri)一步直接固定在四通道丝网印刷碳电极表面,制成快速检测福氏志贺氏菌的酶免疫传感电极。采用原子力显微镜表征不同修饰电极的表面形态,循环伏安法考察不同电极的电化学特性和监测酶促反应,利用还原峰峰电流的减小来测定福氏志贺氏菌。在优化的测定条件下,免疫电极对福氏志贺氏菌的检测范围为104～1010cfu/mL,检出限为2.3×104cfu/mL(S/N=3)。而且该酶免疫传感电极具有较好的特异性、重现性、稳定性和准确性,该方法还具有快速、简便、易于操作和价格低廉等优点,具有用于福氏志贺氏菌快速筛检的潜力。

A disposable Shigella flexneri （S. flexneri） immunoelectrode based on MWCNT/chitosan/HRP- anti-S, flexneri biocomposite on screen-printed electrode without other cross-linked reagents has been developed. The MWCNT/chitosan matrix provided a congenial microenvironment for the immobilization of HRP-anti-S. flexneri and promoted the electron transfer. Due to the strong electrocatalytic properties of HRP and MWCNT toward H2O2, the current signal was significantly amplified. The atomic force microscope （AFM） technology was used to characterize the surface morphologies of different modified films. And cyclic voltammetry （CV） was carried out to characterize the electrochemical properties of different electrodes and detecte S. flexneri. Under optimal conditions, concentrations of S. flexneri from 10^4 to 10^10cfu/ mL could be detected, with a detection limit of 2.3× 10^4 cfu/mL （S/N= 3）. The proposed immunoelectrode displayed a satisfactory stability, reproducibility and accuracy. Moreover, the immunoelectrode was inexpensive,relatively simple to fabricate and had a potential possibility for early assessment of S. flexneri.