Multi-nanomaterial electrochemical biosensor based on label-free graphene for detecting cancer biomarkers

• An electrochemical biosensor based on a graphene (GR) platform, combined with magnetic beads (MBs) and enzyme-labeled antibody-gold nanoparticle bioconjugate was developed for detecting cancer biomarkers.
• Sensitivity of the biosensor was enhanced by modifying the gold nanoparticles (AuNPs) with horseradish peroxidase (HRP) and the detection antibody (Ab2).
• The multi-nanomaterial electrode allows the biosensor to detect the model protein carcinoembryonic antigen (CEA) with high sensitivity and specificity.

Developing a rapid, accurate and sensitive electrochemical biosensor for detecting cancer biomarkers is important for early detection and diagnosis. This work reports an electrochemical biosensor based on a graphene (GR) platform which is made by CVD, combined with magnetic beads (MBs) and enzyme-labeled antibody-gold nanoparticle bioconjugate. MBs coated with capture antibodies (Ab1) were attached to GR sheets by an external magnetic field, to avoid reducing the conductivity of graphene. Sensitivity was also enhanced by modifying the gold nanoparticles (AuNPs) with horseradish peroxidase (HRP) and the detection antibody (Ab2), to form the conjugate Ab2–AuNPs–HRP. Electron transport between the electrode and analyte target was accelerated by the multi-nanomaterial, and the limit of detection (LOD) for carcinoembryonic antigen (CEA) reached 5 ng mL−1. The multi-nanomaterial electrode GR/MBs–Ab1/CEA/Ab2–AuNPs–HRP can be used to detect biomolecules such as CEA. The EC biosensor is sensitive and specific, and has potential in the detection of disease markers.