Graphene Oxide Thin Film with Dual Function Integrated into a Nanosandwich Device for in Vivo Monitoring of Interleukin‑6
journal contributionposted on 09.11.2017, 00:00 by Meng Qi, Jiawei Huang, Hui Wei, Chaomin Cao, Shilun Feng, Qing Guo, Ewa M. Goldys, Rui Li, Guozhen Liu
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.