Cubic CeO2 implanted reduced graphene oxide-based highly sensitive biosensor for non-invasive oral cancer biomarker detection

Abstract

Herein, we report a cerium oxide nanocubes (ncCeO ₂)–reduced graphene oxide (RGO)-based nanocomposite for the detection of oral cancer biomarker, cytokeratin fragment-21-1 (Cyfra-21-1), using the electrochemical technique.

Abstract

Herein, we report a cerium oxide nanocubes (ncCeO ₂)–reduced graphene oxide (RGO)-based nanocomposite for the detection of oral cancer biomarker, cytokeratin fragment-21-1 (Cyfra-21-1), using the electrochemical technique. Nanocomposite of ncCeO ₂–RGO was prepared by the in situ reduction of graphene oxide (GO), in the presence of ncCeO ₂, using hydrazine hydrate. Raman spectra confirmed the presence of ncCeO ₂ in the matrix of RGO. The chemical composition of the ncCeO ₂–RGO nanocomposite was determined by X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) studies have indicated the presence of crystalline ncCeO ₂ and the amorphous nature of RGO. Thin films of ncCeO ₂–RGO composites were spin coated onto the indium tin oxide (ITO) coated glass surface and used for the co-immobilization of specific antibody of Cyfra-21-1 by N-ethyl- N-(3-dimethyl aminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide (EDC–NHS) coupling chemistry. Electrochemical response studies were monitored by using the differential pulse voltammetry (DPV) technique in the range of 0.625 pg mL ⁻¹ to 15 ng mL ⁻¹. The best linear response was observed in the range of 0.625 pg mL ⁻¹ to 0.01 ng mL ⁻¹, with a low detection limit of 0.625 pg mL ⁻¹. The sensitivity was found to be 14.5 μA ng ⁻¹ mL cm ⁻² with R ² 0.98, which was an improvement compared to the results from previously reported work. This BSA/anti-Cyfra-21-1/ncCeO ₂–RGO/ITO immunosensor shows selectivity towards Cyfra-21-1 in the presence of glucose, sodium chloride (NaCl), mucin 16 (MUC-16) and interleukin 8 (IL-8).