RuO₂/rGO heterostructures as mimic peroxidases for colorimetric detection of glucose

The successful synthesis of ruthenium oxide/reduced graphene oxide (RuO₂/rGO) heterostructures by one-pot hydrothermal method using graphene oxides and RuCl₃ as precursors is reported. The heterostructures had high peroxidase-like (POD-like) activities, which catalyzes the oxidation of classical peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H₂O₂ to create a blue colored reaction product. The catalytic activity was significantly enhanced by the synergistic effect between RuO₂ nanoparticles and rGO. RuO₂/rGO had a low K_m of 0.068 mM and a high v_max of 1.228 × 10^-7 M·s^-1 towards TMB in the TMB-H₂O₂ catalytic oxidation system. In addition, the POD-like activity originating from the electron transfer mechanism was confirmed by cytochrome C (Cyt C) oxidation experiment. A colorimetric method based on RuO₂/rGO heterostructures was developed with good sensitivity and selectivity for glucose detection with a limit of detection of 3.34 μM and a linear range of 0-1500 μM. The RuO₂/rGO heterostructures have potential applications in the biomedical areas, such as biosensor and diagnostics.