Peroxidase-like activity of palladium nanoparticles on hydrogen-bond supramolecular structures over a broader pH range and their application in glucose sensing

To circumvent the complicated natural peroxidases, palladium nanoparticles embedded in melamine cyanurate (MCA-Pd NPs) were synthesized. MCA-Pd NPs catalyzed the oxidation of ABTS(2-)by H2O2, and the solution turned green, which could be quantified via a typical absorption peak at 420 nm. MCA-Pd NPs had high peroxidase-like activity in a wider pH range than that of natural peroxidases. MCA-Pd NPs were used to develop a colorimetric sensor for H2O2 over the pH range of 7.0 to 11.0, which had same linear range, and their linear regression equations had similar slopes. Moreover, MCA-Pd NPs were applied to establish the biosensor for glucose by using glucose oxidase (GOx); it had a linear range of 5.0-120 mu mol/L, with a linear regression equation of A = 0.04926 + 0.00536C (C: mu mol/L, R = 0.9960) and a detection limit of 0.3 mu mol/L (3 sigma/slope). When we applied it to detect glucose level in human blood, satisfactory results were obtained.