Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
Biosens Bioelectron. 2018 Aug 15;113:88-94. doi: 10.1016/j.bios.2018.04.056. Epub 2018 Apr 30.
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 HO 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.
本文报道了一种电化学免疫传感器的研制及其性能，该传感器采用磁性多壁碳纳米管（m-MWCNTs）作为纳米载体标签，用于测定人胎球蛋白 A（HFA）。HFA 是肥胖、胰岛素抵抗、2 型糖尿病以及胰腺和肝癌和炎症过程的相关生物标志物。丝网印刷碳电极接枝对氨基苯甲酸，链霉亲和素通过共价固定在电极表面。生物素化的捕获抗体通过链霉亲和素-生物素相互作用固定，采用 HRP 偶联的磁性多壁碳纳米管和抗 HFA 抗体作为检测标记，构建三明治免疫分析方法。通过添加 HO 作为 HRP 底物，在-200 mV 电化学还原苯醌产生的电流来测定 HFA。所制备的 m-MWCNTs 通过 SEM、TEM、XRD 和 EDS 进行了表征。通过电化学阻抗谱和循环伏安法监测了免疫传感器制备过程中的所有步骤。在 20 至 2000 pg/mL 范围内，HFA 的线性校准曲线具有 16 pg/mL 的检出限。与 ELISA 试剂盒和计时阻抗免疫传感器相比，该性能有显著提高。与未掺入磁性颗粒的 MWCNTs 相比，m-MWCNTs 对这种优异的分析性能的有利贡献也得到了强调。该免疫传感器对其他蛋白质和潜在干扰化合物具有出色的选择性。此外，通过对经最小样品处理的唾液中 HFA 的分析，验证了该免疫传感器的实用性。
