Supramolecular assembly of enzyme on functionalized graphene for electrochemical biosensing

The self-assembly of cyclodextrin (CD) functionalized graphene (GR) and adamantane-modified horseradish peroxidase (HRP-ADA) by host–guest supramolecular interaction into novel nanostructures in aqueous solution is reported in the present study. Electrochemical impedance spectroscopy and cyclic voltammetry were applied to characterize the self-assembly process and study the electrochemical behaviors of the immobilized proteins. UV–vis spectra indicated that the native structure of HRP was maintained after the assembly, implying good biocompatibility of CD-functionalized GR (CD-GR). Furthermore, the HRP-ADA/CD-GR composites were utilized for the fabrication of enzyme electrodes (HRP-ADA/CD-GR electrodes). The proposed biosensor showed good reproducibility and high sensitivity to H2O2 with the detection limit of 0.1 μM. In the range of 0.7–35 μM, the catalytic reduction current of H2O2 was proportional to H2O2 concentration.

► Cyclodextrin-graphene nanocomposite was synthesized by a simple chemical strategy. ► HRP was immobilized on the nanocomposite matrix by host–guest supramolecular interactions. ► Immobilized HRP can communicate electrons with electrode efficiently. ► Biosensor exhibited good analytical performance toward the quantification of H2O2. ► Biosensor can be successfully applicable for practical H2O2 detection.