基于氧化锌纳米花的心肌肌钙蛋白I夹心式电化学免疫传感器构建研究

Zincoxide Nanoflower Labeled Sandwich Electrochemical Sensor for Detection of Cardiac Troponin I

目的结合氧化锌纳米花及夹心法信号放大策略,构建高灵敏心肌肌钙蛋白I(cTnI)电化学免疫传感器。方法采用直接沉淀法合成氧化锌纳米花,在其表面标记硫堇与cTnI抗体。另外,采用恒电位溶出法在电极表面沉积纳米金,通过金-氮共价键捕获cTnI抗体作为传感平台,识别检测抗体,构成夹心式、高灵敏cTnI电化学免疫传感器。采用扫描电子显微镜(SEM)表征材料的形貌结构,采用循环伏安法和示差脉冲伏安法(DPV)探究传感界面的构建过程、实验条件以及响应性能。结果功能化氧化锌纳米花与纳米金呈现出良好的信号放大性能。在最优实验条件下,免疫传感器DPV响应电流与cTnI抗原浓度呈正比,线性范围为0.05~0.25μg/L和0.50~8.00μg/L,检测限为0.0143μg/L(S/N=3)。构建的电化学免疫传感器具备良好的选择性、重现性及准确度。结论结合氧化锌纳米花优异的催化性能,成功构建一种双抗夹心式cTnI电化学免疫传感器,提高了cTnI检测的灵敏度与特异度。

Objective To construct a highly sensitive cardiac troponin I(cTnI)electrochemical immunosensor based on zinc oxide nanoflowers and sandwich signal amplification strategy.Methods Zinc oxide nanoflowers were prepared by direct precipitation method and labeled with thionine and cTnI antibodies.In addition,gold nanoparticles were deposited on the electrode surface by potentiostatic stripping method,cTnI antibody was trapped by gold-nitrogen covalent bond to form a sensing platform for antibody identification and detection,and thus a sandwich,highly sensitive cTnI electrochemical immunosensor was constructed.The scanning electron microscope structure was characterized by scanning electron microscopy(SEM).And the construction process of the sensing interface,experimental conditions and the response performance of the sensor were investigated by cyclic voltammetry(CV)and differential pulse voltammetry(DPV).Results Functional zinc oxide nanoflowers and nano-gold showed good signal amplification performance.Under optimal conditions,the DPV current response value of the sensor and cTnI concentration showed a good linear relationship in the range of 0.05-0.25μg/L and 0.50-8.00μg/L,respectively,with the detection limit of 0.0143μg/L(S/N=3).The constructed immune sensor had good selectivity,reproducibility and accuracy.Conclusion A sandwich,electrochemical immunosensor for cTnI is successfully constructed based on the excellent catalytic properties of zinc oxide nanoflowers,which improves the sensitivity and specificity of cTnI detection.