Bio-functionalized graphene–graphene oxide nanocomposite based electrochemical immunosensing

We report a novel in-situ electrochemical synthesis approach for the formation of functionalized graphene–graphene oxide (fG–GO) nanocomposite on screen-printed electrodes (SPE). Electrochemically controlled nanocomposite film formation was studied by transmission electron microscopy (TEM) and Raman spectroscopy. Further insight into the nanocomposite has been accomplished by the Fourier transformed infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and X-ray diffraction (XRD) spectroscopy. Configured as a highly responsive screen-printed immunosensor, the fG–GO nanocomposite on SPE exhibits electrical and chemical synergies of the nano-hybrid functional construct by combining good electronic properties of functionalized graphene (fG) and the facile chemical functionality of graphene oxide (GO) for compatible bio-interface development using specific anti-diuron antibody. The enhanced electrical properties of nanocomposite biofilm demonstrated a significant increase in electrochemical signal response in a competitive inhibition immunoassay format for diuron detection, promising its potential applicability for ultra-sensitive detection of range of target analytes.

Description: Illustration of in-situ electrochemical synthesis of fG–GO nanocomposite on screen printed electrodes and subsequent immunoassay development. The nanocomposite was formed by electrochemical reduction of GO. The immunoassay was performed using alkaline phosphatase (AP) labeled rabbit anti-IgG followed by recording of the electroactive product naphthol.Figure optionsDownload as PowerPoint slideHighlights
► Novel graphene oxide based nanocomposite synthesized by controlled electrochemical synthesis.
► Nanocomposite demonstrated good electronic properties and versatile chemical functionality.
► Nanocomposite modified electrode exhibited detection limit of 0.01 pg mL−1 for herbicide diuron.
► The newly developed sensing platform promised practical usage in ultrasensitive immunosensing.