基于四氧化三铁磁性纳米粒子的微囊藻毒素免疫传感器研究

Electrochemical Immunosensor for Microcystins Based on Magnetic Ferriferrous Oxide Nanoparticles Modified Electrode

采用化学共沉淀法制备四氧化三铁（Fe_3O_4）磁性纳米粒子（MNPs）,依次用3-氨基丙基三乙氧基硅烷（APTS）、丁二酸酐（SAH）对Fe_3O_4MNPs表面进行修饰,得到羧基功能化的核壳型磁性纳米粒子（Fe_3O_4@APTS·SAH MNPs）,分别采用透射电镜（TEM）、磁滞回线、X射线光电子能谱（XPS）和傅里叶红外光谱（FTIR）对其进行了表征。将此纳米粒子修饰在自制的磁性玻碳电极（MGCE）表面,用1-（3-二氨基丙基）-3-乙基碳二亚胺盐酸盐（EDC）和N-羟基琥珀酰亚胺（NHS）活化纳米粒子表面的羧基,通过与氨基的共价交联,将抗微囊藻毒素-（亮氨酸-精氨酸）（MCLR）抗体（anti-MCLR）固定于该修饰电极上,用牛血清白蛋白（BSA）封闭非特异性吸附位点,构建了一种检测MCLR的电流型免疫传感器。采用直接竞争免疫反应模式,在标记物辣根过氧化物酶（HRP）的MCLR（MCLR-HRP）存在下,利用差分脉冲伏安法（DPV）测定溶液中的微囊藻毒素。在优化的实验条件下,免疫传感器对MCLR的线性测定范围为0.05~100μg/L,检出限为0.01μg/L（S/N=3）。构建的免疫传感器呈现出良好的重现性、稳定性和特异性。将本传感器用于实际水样的测定,加标回收率为94.3%~99.5%。

An immunosensor for detection of microcystin-（leucine-arginine） （MCLR） was constructed. Chemical co-precipitation method was used to synthesize ferriferrous oxide magnetic nanoparticles （Fe304 MNPs）. The Fe3 04 MNPs were modified with 3-aminopropyltriethoxysilane （APTS） and succinic anhydride （SAH） in turn to generate carboxyl-functionalized core-shell MNPs （ F%O4@ APTS · SAH MNPs）, which were characterized by transmission electron microscope （TEM）, hysteresis loop, X-ray photoelectron spectroscopy （XPS） and Fourier transform infrared spectroscopy （FTIR） , respectively. The Fe3 04 @ APTS · SAH MNPs were modified onto the surface of a home-made magnetic glassy carbon electrode （MGCE）. Anti- MCLR antibody （anti-MCLR） was immobilized on the modified MGCE by coupling reaction with ethyl-3- （dimethyl aminopropyl ） carbodiimide （ EDC ） and N-hydroxysuccinimide （ NHS ）. Subsequently, bovine serum albumin （BSA） was used to block the non-specific adsorption sites of the electrode. Direct competitive immunoassay format was adopted. In the presence of horseradish peroxidase-conjugated MCLR （MCLR- HRP）, MCLR in solution was determined by differential pulse vohammetry （DPV）. Under the optimized conditions, MCLR could be detected within a wide linear range of 0.05-100 μg/L with a detection limit of 0.01 μg/L （S/N=3）. Moreover, the immunosnssoe exhibited good reproducibility, stability and selectivity. The immunosensor was applied for the determination of MCLR in real water samples with the recoveries from 94.3% to 99.5%.