基于镍-金属有机框纳米酶活性的氯霉素核酸适配体传感器构建和应用

Construction and application of chloramphenicol aptasensor based on the nanozyme activity of nickel-metal-organic framework

中文关键词:  电化学传感器  金属有机材料  氯霉素  核酸适配体  鲜虾

英文关键词:electrochemical sensor  metal-organic framwork  chloramphenicol  aptamer  fresh shrimp

中文摘要:

      目的 构建新型的免标记核酸适配体电化学传感器, 并应用于海鲜产品中氯霉素(chloramphenicol, CAP)残留的检测分析。方法 以NiCl2、2,3,6,7,10,11-六羟基三亚苯(2,3,6,7,10,11-hexahydroxytriphenyl, HHTP)为原料, 通过原位法在羧基化玻碳电极(glassy carbon electrode, GCE)表面合成Ni-HHTP金属-有机框架材料(metal-organic framework, MOF), 得到Ni-HHTP修饰电极(Ni-HHTP/GCE)。采用X射线衍射(X-ray diffraction, XRD)、扫描电镜(scanning electron microscopy, SEM)和衰减全反射-傅里叶变换红外光谱法(attenuated total reflection-Fourier transform infrared spectroscopy, ATP-FTIR)对电极表面的Ni-HHTP形貌和结构进行表征。将CAP核酸适配体(c-APT)通过滴涂法非共价吸附在Ni-HHTP/GCE表面, 构建新型的免标记c-APT电化学传感界面, 并应用于市售鲜虾中CAP残留的检测。结果 通过原位组装法, 在羧基化GCE表面制备了均匀分布的直径约为40 nm的Ni-HHTP纳米颗粒。电化学实验表明, Ni-HHTP具有过氧化物酶特征, 能催化H2O2氧化, 且通过π-π堆积吸附了c-APT后, 催化活性进一步增强。当c-APT与目标物CAP结合并从电极表面脱落后, 催化性能减弱。在最佳实验条件下, 计时安培催化电流值(I, μA)与CAP浓度负对数(?logCCAP, CCAP单位为: mol/L)在0.30 pmol/L~3.00 μmol/L范围内呈现良好的线性关系, 线性方程为I=?0.0385logCCAP+2.75, 相关系数为0.9951, 检出限为0.029 pmol/L。传感器对CAP具有良好的特异性识别; 4℃保存7 d后, Ni-HHTP/GCE电极对H2O2催化活性仍能保持95.7%, 说明该传感器具有良好的稳定性。市售鲜虾肉萃取液CAP加标回收率为94.0%~108.0%。结论 以Ni-HHTP为传感材料、c-APT为识别元件的电化学免标记传感界面可应用于水产品中CAP残留的快速和灵敏检测。

英文摘要:

      Objective To construct a novel lable-free electrochemical aptasensor for the determination of chloramphenicol (CAP) residues in seafood products. Methods With NiCl2, 2,3,6,7,10,11-hexahydroxytriphenyl (HHTP) as raw materials, the metal-organic framework (MOF) material of Ni-HHTP had been in-situ prepared on the surface of the carboxylated glassy carbon electrode (GCE) to obtain the Ni-HHTP modified electrode (Ni-HHTP/GCE). The morphology and structure of Ni-HHTP on electrode surface were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). A novel sensing interface for CAP was constructed by non-covalent adsorption of CAP aptamer (c-APT) onto Ni-HHTP/GCE, which was applied for the analysis of CAP in fresh shrimp products purchased from the market. Results The Ni-HHTP nanoparticles with the diameter of 40 nm were uniformly coated on the surface of carboxylated GCE by in-situ assembly method. Electrochemical experiments showed that Ni-HHTP had peroxidase characteristics to catalyze the oxidation of H2O2, and the catalytic performance was further enhanced after the π-π stacking adsorption of c-APT. When the c-APT bonded with the target of CAP and fell off from the electrode surface, the catalytic performance was weakened. Under the optimal experimental conditions, the catalytic current value (I, μA) had a good linear relationship with the logarithm value of CAP concentration (?logCCAP, CCAP unit: mol/L) in the concentration range from 0.30 pmol/L to 3.00 μmol/L, the linear equation was expressed as I=?0.0385logCCAP+2.75 with a correlation coefficient of 0.9951, the limit of detection was 0.029 pmol/L. The sensor showed good response specificity for CAP, and the catalytic activity of Ni-HHTP/GCE electrode remained 95.7% after storage in 4℃ for 7 days, indicating that the sensor had good stability. The standard recoveries were in the range of 94.0%?108.0% for the commercially available fresh shrimp meat extract. Conclusion The electrochemical label-free sensing interface with Ni-HHTP as sensing material and c-APT as the recognition element can be applied to the rapid and sensitive detection of CAP residues in aquatic products.