Immobilization of antibodies on aldehyde-functionalized polymer/graphene films for the fabrication of a label-free electrochemical immunosensor

• A novel aldehyde-functionalized polymer was synthesized.
• Aldehyde-functionalized polymer was used to immobilize antibodies.
• Graphene was used to improve the conductivity of sensing interface.
• The proposed immunosensor is simple, label-free and specific.

Using poly-(epichlorohydrin) and 4-pyridinecarboxaldehyde, we synthesized a new aldehyde-functionalized polymer, which was applied to simplify antibody immobilization on the electrode surface, in which no additional chemical cross-linking is required. Combined with the advantages of graphene, a label-free electrochemical immunosensor based on graphene/aldehyde-containing polymer film for α-fetoprotein detection was fabricated. α-Fetoprotein was detected within the range from 0.05 to 35 ng mL− 1 with a detection limit of 0.02 ng mL− 1 obtained by 3 S/N. The proposed immunosensor is easy, label-free, specific and thus provides a good diagnostic tool for detection of α-fetoprotein and other cancer markers.