Graphene oxide (GO), with its exceptional physical and chemical properties and biocompatibility, holds a tremendous potential for sensing applications. In this study, GO, acting both as the electron-transfer bridge and the signal reporter, was attached on the interface to develop a label-free electrochemical nanosandwich device for detection of interleukin-6 (IL-6). First, a single layer of GO was covalently modified on gold electrodes, followed by attachment of anti-IL-6 capture antibody to form the sensing interface. The 4-aminophenyl phosphorylcholine was further attached to the surface of GO to minimize nonspecific protein adsorption. For reporting the presence of analyte, the anti-IL-6 detection antibody was covalently modified to the GO, which has been integrated with the redox probe Nile blue (NB). Finally, a nanosandwich assay was fabricated on gold surfaces for detection of IL-6 on the basis of the electrochemical signal of NB. The prepared nanosandwiches demonstrated high selectivity and stability for detection of IL-6 over the range of 1–300 pg mL^–1 with the lowest detectable concentration of 1 pg mL^–1. The device was successfully used for monitoring of IL-6 secretion in RAW cells and live mice. By tailoring the GO surface with functional components, such devices were able to detect the analyte in vivo without causing inflammatory response.

中文翻译：

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纳米三明治装置中集成双重功能的氧化石墨烯薄膜，用于白细胞介素6的体内监测

氧化石墨烯（GO）具有出色的物理和化学特性以及生物相容性，在传感应用中具有巨大的潜力。在这项研究中，GO既充当电子传输桥又充当信号报告器，被连接到界面上，以开发用于检测白介素6（IL-6）的无标记电化学纳米夹心设备。首先，在金电极上共价修饰单层GO，然后附着抗IL-6捕获抗体以形成传感界面。将4-氨基苯基磷酸胆碱进一步连接到GO的表面，以最大程度地减少非特异性蛋白质的吸附。为了报告分析物的存在，将抗IL-6检测抗体共价修饰为GO，该GO已与氧化还原探针尼罗蓝（NB）整合在一起。最后，在NB表面的电化学信号的基础上，在金表面上制备了纳米三明治测定法以检测IL-6。制备的纳米三明治对1-600 pg mL范围内的IL-6的检测具有很高的选择性和稳定性^–1的最低可检测浓度为1 pg mL ^–1。该设备已成功用于监测RAW细胞和活小鼠中IL-6的分泌。通过使用功能组件定制GO表面，此类设备能够在体内检测分析物而不会引起炎症反应。