A Novel Molecularly Imprinting Biosensor Including Graphene Quantum Dots/Multi-Walled Carbon Nanotubes Composite for Interleukin-6 Detection and Electrochemical Biosensor Validation

Abstract

Interleukin-6 (IL-6) as a pro-inflammatory cytokine demonstrate a critical role in the inflammatory response. Especially, the high levels of IL-6 measured in plasma have been associated with pathological inflammation. In this report, new molecularly imprinting biosensor on graphene quantum dots (GQDs)/functionalized multi-walled carbon nanotubes (f-MWCNTs) composite were prepared for IL-6 protein detection. The structures of GQDs, f-MWCNTs and GQDs/f-MWCNTs composite were highlighted by scanning electron microscope (SEM), transmission electron microscopy (TEM), raman spectroscopy, UV-vis spectroscopy, fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and X-ray diffraction (XRD) method. Surface morphology characterization shows the nanoporous cavities as an effective biosensing area. IL-6 protein imprinted electrode was prepared on GQDs/f-MWCNTs composite in the presence of 100.0 mM pyrrole containing 25.0 mM IL-6 protein. 0.01-2.0 pg ml(-1) and 0.0030 pg ml(-1) were found as linearity range and the detection limit (LOD) for analytical application in plasma samples. Finally, the validated biosensor was examined in terms of stability, repeatability and reproducibility.