基于HDT自组装金纳米粒子修饰电极的微囊藻毒素-LR电化学免疫传感器研究

Study on Electrochemical Immunosenor for Microcystin-LR Based on HDT Self-assembly Au Nanoparticle Modified Electrode

构建了一种新型的基于金纳米粒子（AuNPs）修饰金电极的微囊藻毒素-亮氨酸-精氨酸（MCLR）电化学免疫传感器。采用柠檬酸钠还原法制备了AuNPs溶胶，分别用透射电子显微镜和紫外-可见吸收光谱对其进行表征。将AuNPs组装到1，6-己二硫醇（HDT）自组装单分子层修饰的金电极表面，再将MCLR抗体（anti-MCLR）固定于该修饰电极上，利用扫描探针显微镜法、循环伏安法和电化学交流阻抗法（EIS）表征了自制化学修饰电极表面的形貌特征和电化学免疫传感器的电化学特征。通过辣根过氧化物酶标记的MCLR（MCLR-HRP）与MCLR竞争结合抗体，建立了检测MCLR的差分脉冲伏安法（DPV）。在最佳实验条件下，用DPV对MCLR检测的线性范围为0.01~25μg/L，检出限为0.005μg/L。对构建的免疫传感器的重现性、稳定性和选择性进行了考察。该方法对实际水样中MCLR的加标回收率为100%~102%，测定结果与高效液相色谱法的测定结果一致。

A novel electrochemical immunosensor for microcystin-（leucine-arginine）（MCLR） was developed based on gold electrode modified with Au nanoparticles（AuNPs）.The AuNPs were prepared by the sodium citrate reduction method,and characterized by transmission electron microscopy（TEM） and UV-vis absorption spectroscopy.1，6-hexanedithiol（HDT） molecules were modified onto the surface of a gold electrode to form self-assembly monolayer, and then the AuNPs were assembled on the self-assembly monolayer of HDT. The immunosensor was constructed by immobilizing the antibody of microcystin-（leucine-arginine）（anti-MCLR） on the modified electrode. The surface morphology of the AuNPs modified electrode and the electrochemical behaviour of the immunosensor were characterized by scanning probe microscopy，cyclic voltammetry and electrochemical impedance spectroscopy（EIS），respectively.MCLR and horseradish peroxidase conjugated MCLR（MCLR-HRP） competitively combined with immobilizing anti-MCLR. The determination of MCLR using the immunosensor was investigated by differential pulse voltammetry（DPV）.Under the optimized conditions，a linear range from 0.01μg/L to 25μg/L and a detection limit of 0.005μg/L were obtained by DPV method.The reproducibility，stability and selectivity of the immunosensor for MCLR were investigated. The proposed method was applied in the determination of MCLR in real water samples with recoveries of 100%-102%,and the determination results of MCLR were consistent with those obtained by HPLC method.