Synthesis of 1,3-di(4-amino-1-pyridinium)propane ionic liquid functionalized graphene nanosheets and its application in direct electrochemistry of hemoglobin

1,3-Di(4-amino-1-pyridinium)propane tetrafluoroborate (DAPPT) ionic liquid was successfully synthesized, and was used as a modifier to functionalize graphene nanosheets through covalent binding of amino groups and epoxy groups in an alkaline solution. The as-prepared graphene-DAPPT nanosheets (Gr-DAPPT) were confirmed with transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/vis and FTIR spectroscopy. A biocompatible platform based on Gr-DAPPT was constructed for the immobilization of hemoglobin (Hb) through a cross-linking step with chitosan and glutaraldehyde. The direct electron transfer and bioelectrocatalytic reaction of Hb immobilized on Gr-DAPPT surface were achieved. A pair of reversible redox peaks of hemoglobin was observed, and bioelectrocatalytic activity toward the reduction of H2O2 was also demonstrated, displaying a potential application for the fabrication of novel biosensors to sense H2O2. Such results indicated that Gr-DAPPT based interface would be a promising platform for biomacromolecular immobilization and biosensor preparation.

► 1,3-Di(4-amino-1-pyridinium)propane tetrafluoroborate ionic liquid was successfully synthesized.
► Ionic liquid modified graphene nanosheets were successfully prepared and fully characterized.
► Hb was immobilized on the as-prepared graphene–ionic liquid nanosheets.
► Direct electrochemistry of Hb was succeeded.
► Biocatalysis of Hb towards H2O2 was demonstrated, and was used in H2O2 determination.