Gold Nanoparticles/Graphdiyne as Sensing Substrate Coupled with UiO-66/ferrocene as Signaling-Amplifier for Sandwich-Type Electrochemical Immunosensing of Interleukin-6

Interleukin-6 (IL-6) is a common proinflammatory cytokine and can be adopted as an important biomarker for several diseases including nasopharynx cancer, pancreatitis, infections, and cardiovascular. It is thus necessary to design an effective method for monitoring IL-6. Herein, by preparing gold nanoparticles/graphdiyne (Au/GRD) nanohybrid with simple electroless deposition as the sensing substrate and UiO-66 metal–organic frameworks/ferrocene (UiO/Fc) as the signaling-amplifier, a highly efficient sandwich-type electrochemical immunosensing (SEI) platform was proposed for IL-6 determination. The superior electrical properties, easy preparation, high surface area, and stability of Au/GRD make it a desirable substrate to immobilize the primary antibody of IL-6. Meanwhile, the unique structure of UiO-66 is beneficial to immobilizing the Fc probe and the secondary antibody. By optimizing experimental conditions, the Fc current obtained at the as-designed SEI platform increases along with IL-6 increase, and the related linearity is 0.5 pg ml −1 –1200.0 pg ml −1 coupled with a low detection limit of 0.2 pg ml −1 . It is expected the as-designed SEI platform based on Au/GRD and UiO/Fc shows potential applications for IL-6 analysis.