一次性免疫传感器快速检测阪崎肠杆菌的研究

Rapid Detection of Enterobacter Sakazakii with [BMIM] PF_6 /Multi-Wall Carbon Nanotube Modified Electrode

为改善基于多壁碳纳米管/Nafion生物传感器电化学信号及储存稳定性,采用[BMIM]PF6/Nafion复合物将辣根过氧化物酶标抗体包埋固定于MWCNT/Nafion修饰的丝网印刷碳电极上,构建了一种新的免疫传感器。用原子力显微镜表征电极各层修饰后的表面形态,用循环伏安法(CV)和交流阻抗法(EIS)考察修饰电极的电化学特性,利用还原峰电流变化对被检物进行测定。本实验选用阪崎肠杆菌为目标抗原,在优化的检测条件下,该方法检测阪崎肠杆菌的线性范围为103～109 cfu/mL,检出限为3.4×102 cfu/mL(S/N=3)。该免疫传感器的储存稳定性有明显改善,4℃放置30 d后电流响应值仍为初始值的95.50%,且具有较高的灵敏度,较好的重现性(RSD<6%)、特异性(非目标抗原的ΔIpc<0.3μA)和准确性(与GB/T 4789.40—2010符合率为100%,出现假阴性概率为5.56%),操作简便、成本低,有很好的潜在应用价值。

For the purpose of improving the electrochemical signal and stability of the biosensor based on MWCNT/Nafion composite,[BMIM]PF6/Nafion/horseradish peroxidase labeled antibody biocomposite film was droped onto screen-printed carbon electrode modified by multi-wall carbon nanotubes（MWCNTs）,a novel immunosensor had been developed for the rapid detection of antigen.The surface morphologies of modified films were characterized by atomic force microscope（AFM）.The assemble procedure was characterized by cyclic voltammetry（CV）and electrochemical impedance spectroscopy（EIS）.Cyclic voltammetry was carried out to quantify the antigen.Using E Sakazakii as a model,under optimal conditions,concentration of E Sakazakii from 103~109 cfu/mL could be detected with a detection limit of 3.4×102 cfu/mL（S/N=3）.The proposed immunoelectrode presented a satisfactory storage stability（the current response was 95.50% of the initial response after being stored at 4 ℃ for a month）,reproducibility（RSD6%）,selectivity（the current changes of non-target antigen ΔIpc0.3 μA）,accuracy（100% of the results obtained by the immunosensor were in agreement with those obtained by GB/T 4789.40—2010,the probability of false negative is 5.56%）,and high sensitivity.Furthermore,the immunoelectrode was inexpensive,relatively simple to fabricate and had potential application for rapid detection.