National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, D09 V209, Ireland.
National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, D09 V209, Ireland.
Anal Chim Acta. 2022 Sep 8;1225:340226. doi: 10.1016/j.aca.2022.340226. Epub 2022 Aug 11.
An immunosensor for label-free electrochemical detection of MiniChromosome Maintenance Protein 5, MCM5, a protein overexpressed in cervical cancer, based on a gold electrode is reported. The electrode was first modified with a submonolayer (capture layer) of 11-mercaptoundecanoic acid (11-MUA) and then activated with N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to immobilize the capture antibody. The change in electrode surface properties (wettability) during the formation of the 11-MUA layers was determined using the static water contact angle (WCA). The binding of MCM5 antigens to the capture antibody was monitored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using 5 mM [Fe(CN)] in 0.1 M LiClO(aq) as an electroactive probe. AC Impedance was used to measure charge transfer resistance (R), which reflects impeded electron transfer when the antigen is bound to the antibody functionalized surface. After exposing the antibody-functionalized surface to MCM5 antigens, R increases linearly with the logarithmic value of MCM5 antigen concentration, with a linear dynamic range of 10 to 10 g/mL, a correlation coefficient of 0.99, and a detection limit of 2.9 pM (10 g/mL). This excellent sensitivity was achieved with simple preparation steps and minimal reagent consumption, without the need for complicated procedures such as enzymatic amplification, fluorescent labeling, or nanoparticle modification.
一种基于金电极的免标记电化学检测微小染色体维持蛋白 5（MCM5）的免疫传感器，MCM5 是宫颈癌中过表达的一种蛋白质。该电极首先用 11-巯基十一酸（11-MUA）的亚单层（捕获层）进行修饰，然后用 N-（3-二甲基氨基丙基）-N-乙基碳二亚胺盐酸盐（EDC）和 N-羟基琥珀酰亚胺（NHS）激活，以固定捕获抗体。通过静态水接触角（WCA）确定在 11-MUA 层形成过程中电极表面性质（润湿性）的变化。使用 5 mM [Fe（CN）]在 0.1 M LiClO（aq）中作为电活性探针通过循环伏安法（CV）和电化学阻抗谱（EIS）监测 MCM5 抗原与捕获抗体的结合。交流阻抗用于测量电荷转移电阻（R），当抗原结合到抗体功能化表面时，R 反映了电子转移的阻碍。将抗体功能化表面暴露于 MCM5 抗原后，R 随 MCM5 抗原浓度的对数线性增加，线性动态范围为 10 至 10 g/mL，相关系数为 0.99，检测限为 2.9 pM（10 g/mL）。这种优异的灵敏度具有简单的制备步骤和最小的试剂消耗，无需复杂的程序，如酶放大、荧光标记或纳米颗粒修饰。
