Dual assaying of breast cancer biomarkers by using a sandwich–type electrochemical aptasensor based on a gold nanoparticles–3D graphene hydrogel nanocomposite and redox probes labeled aptamers

A sandwich–type electrochemical aptasensor for the individual and simultaneous detection of CEA and CA 15–3 biomarkers based on a gold nanoparticles–3D graphene hydrogel nanocomposite and redox probes labeled aptamers [Display omitted] •A sandwich aptasensor was introduced for the simultaneous determination of CA 15–3 and CEA.•Gold nanoparticles 3D graphene hydrogel was used as a sensing substrate.•Redox probe-labeled aptamers were used as biosensing probes.•The duplexed aptasensor was useful for the simultaneous determination of two biomarkers in human serum samples. The present study was conducted to fabricate a sandwich–type electrochemical aptasensor for the simultaneous determination of two important biomarkers in breast cancer, namely carcinoembryonic antigen (CEA) and cancer antigen 15–3 (CA 15–3). Gold nanoparticles three–dimensional graphene hydrogel (AuNPs/3DGH) nanocomposite was used as a biosensing substrate. CEA and CA 15–3 aptamers linked to gold nanoparticles/redox probe/graphene nanocomposite were used as biosensing probes. Herein, hemin and ferrocene had the role of redox probes for CEA and CA 15–3 respectively and provided electrochemical signals for dual biomarker detection. CEA and CA 15–3 aptamers were immobilized on the surface of an AuNPs/3DGH–modified electrode. The peak currents and the potentials in differential pulse voltammograms reflected the concentration and the nature of the biomarkers. The detection limits of CEA and CA 15–3 at the surface of the duplexed aptasensor were found to be 11.2 pg mL–1 and 11.2 × 10–2 U mL–1, respectively. The duplexed aptasensor was also used to analyze clinical serum samples. The results were in good agreement with the ELISA method, indicating the good reliability of the aptasensor.