AbstractThe 6-kDa early secretory antigenic target referred to as ESAT-6 is a virulence factor secreted by Mycobacterium tuberculosis (MTB). This work describes a voltammetric aptasensor for ultrasensitive detection of ESAT-6. Reduced graphene oxide doped with metal-organic framework (MOF-rGO) was deposited on a glassy carbon electrode (GCE). This increases the immobilization of electroactive Toluidine Blue (TB) and facilitates the electron transfer from TB to the modified GCE. Platinum/gold core/shell (Pt@Au) nanoparticles were used to assemble thiolated ESAT-6 binding aptamer (EBA) on a modified electrode and to further amplify the response to TB. The modified GCE, typically operated at −0.36 V (vs. SCE), has a linear response in 1.0 × 10−4 to 2.0 × 102 ng⋅mL-1 ESAT-6 concentration range, and the limit of detection (LOD) for ESAT-6 is as low as 3.3 × 10−5 ng⋅mL-1. It exhibits satisfactory specificity and reproducibility when analyzing spiked human serum. Graphical abstractSchematic presentation of a voltammetric aptasensor for Mycobacterium tuberculosis antigen ESAT-6 using a glassy carbon electrode modified with reduced graphene oxide (rGO) and a metal-organic framework (MOF). The limit of detection for ESAT-6 is as low as 3.3 × 10−5 ng/mL.

中文翻译：

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基于适配体的结核分枝杆菌抗原 ESAT-6 伏安生物传感器使用由还原氧化石墨烯和金属有机框架组成的纳米杂化材料

摘要 6-kDa 早期分泌抗原靶标 ESAT-6 是一种由结核分枝杆菌 (MTB) 分泌的毒力因子。这项工作描述了一种用于 ESAT-6 超灵敏检测的伏安适体传感器。掺杂有金属有机骨架的还原氧化石墨烯 (MOF-rGO) 沉积在玻璃碳电极 (GCE) 上。这增加了电活性甲苯胺蓝 (TB) 的固定化，并促进了电子从 TB 转移到修饰的 GCE。铂/金核/壳（Pt@Au）纳米颗粒用于在修饰电极上组装硫醇化 ESAT-6 结合适体（EBA）并进一步放大对 TB 的响应。改进的 GCE 通常在 -0.36 V（相对于 SCE）下运行，在 1.0 × 10−4 至 2.0 × 102 ng⋅mL-1 ESAT-6 浓度范围内具有线性响应，ESAT-6 的检测限 (LOD) 低至 3.3 × 10−5 ng⋅mL-1。在分析加标人血清时，它表现出令人满意的特异性和重现性。图解摘要使用还原氧化石墨烯 (rGO) 和金属有机框架 (MOF) 修饰的玻璃碳电极，用于检测结核分枝杆菌抗原 ESAT-6 的伏安适体传感器的示意图。ESAT-6 的检测限低至 3.3 × 10−5 ng/mL。