Photoluminescent C-dots@RGO for sensitive detection of hydrogen peroxide and glucose

We have demonstrated sensitive detections of hydrogen peroxide (H2O2) and glucose using reduced graphene oxide decorated with carbon dots (C-dots@RGO). The C-dots@RGO prepared from catechin (reducing agent and carbon source) and graphene oxide via hydrothermal routes possesses excitation-wavelength-dependence photoluminescence (PL) characteristics, with maximum excitation and emission wavelengths of 365 and 440nm, respectively. The C-dots@RGO is stable in solution containing NaCl up to 350mM, but is quenched by reactive oxygen species (ROS). ROS reacts with H2O2 and thus its PL quenching toward the C-dots@RGO is minimized. When using C-dots@RGO and glucose oxidase (GOx), the PL assay allows detection of glucose in the presence of 10µM of bovine serum albumin, with linearity over a concentration range from 1 to 60µM (r=0.99) and a limit of detection (at a signal-to-noise ratio of 3) of 140nM. The practicality of this assay has been validated by determining the concentrations of glucose in serum and saliva samples, with results of 5.1±0.6mM (n=3) and 117.9±8.1μM (n=3), respectively. Our simple and sensitive assay opens a new avenue of developing assays for various analytes using C-dots@RGO in conjunction with different enzymes. •C-dots@RGO were used for sensitive detections of H2O2 and glucose.•The LOD for glucose in the presence of bovine serum albumin was 140nM.•This assay was highly selective towards glucose.•Glucose concentrations in blood and saliva samples were determined.