This paper reports the development and performance of an electrochemical immunosensor using magnetic multiwalled carbon nanotubes (m-MWCNTs) as nanocarrier tags for the determination of human fetuin A (HFA), a relevant biomarker of obesity, insulin resistance, and type-2 diabetes as well as for pancreatic and liver cancers and inflammatory processes. Screen-printed carbon electrodes were grafted with p-aminobezoic acid and streptavidin was covalently immobilized on the electrode surface. A biotinylated capture antibody was immobilized through streptavidin-biotin interaction and a sandwich assay configuration was implemented using m-MWCNTs conjugated with HRP and anti-HFA antibodies as the detection label. The determination of HFA was accomplished by measuring the current produced by the electrochemical reduction of benzoquinone at −200 mV upon addition of H₂O₂ as HRP substrate. The prepared m-MWCNTs were characterized by SEM, TEM, XRD and EDS. All the steps involved in the immunosensor preparation were monitored by electrochemical impedance spectroscopy and cyclic voltammetry. A linear calibration plot for HFA was found between 20 and 2000 pg/mL with a LOD value of 16 pg/mL. This performance is notably better than that reported for an ELISA kit and a chronoimpedimetric immunosensor. The favorable contribution of m-MWCNTs in comparison with MWCNTs without incorporated magnetic particles to this excellent analytical performance is also highlighted. The immunosensor selectivity against other proteins and potentially interfering compounds was excellent. In addition, the usefulness of the immunosensor was demonstrated by the analysis of HFA in saliva with minimal sample treatment.

本文报道了使用磁性多壁碳纳米管（m -MWCNTs）作为纳米载体标签的电化学免疫传感器的开发和性能，该标签可用于测定人胎球蛋白A（HFA），肥胖，胰岛素抵抗和2型糖尿病的相关生物标志物。以及胰腺癌，肝癌和炎症过程。将丝网印刷的碳电极接枝对氨基苯甲酸，并将抗生蛋白链菌素共价固定在电极表面。通过链霉亲和素与生物素的相互作用固定了生物素化的捕获抗体，并使用m与HRP和抗HFA抗体缀合的-MWCNTs作为检测标记。通过添加H ₂ O ₂作为HRP底物，通过测量在-200 mV下苯并醌的电化学还原所产生的电流来完成HFA的测定。用SEM，TEM，XRD和EDS对制备的m- MWCNTs进行了表征。免疫传感器制备中涉及的所有步骤均通过电化学阻抗谱和循环伏安法进行监测。发现HFA的线性校准图介于20和2000 pg / mL之间，LOD值为16 pg / mL。该性能明显优于ELISA试剂盒和计时阻抗免疫传感器的报告性能。m-的有利贡献与未掺入磁性颗粒的MWCNT相比，MWCNT具有出色的分析性能。对其他蛋白质和潜在干扰化合物的免疫传感器选择性非常好。此外，通过最少的样品处理即可分析唾液中的HFA，从而证明了免疫传感器的实用性。