Histidine capped-gold nanoclusters mediated fluorescence detection of glucose and hydrogen peroxide based on glucose oxidase-mimicking property of gold nanoparticles via an inner filter effect mechanism

Here we reported an inner filter effect (IFE)-based simple assay system for the detection of glucose and hydrogen peroxide in the absence of glucose oxidase (GOx) enzyme, taking the advantage of the intrinsic GOx-like catalytic activity of gold nanoparticles (AuNPs). In this assay, the AuNPs were applied as GOx-mimicking catalysts to oxidation of glucose for in-situ production of H2O2, which in turn, can react with HAuCl4 to produce Au0 for deposition on the AuNPs core and result in the enlargement of self-catalyzed AuNPs and alteration of its absorption spectrum. The intensity of the surface Plasmon resonance (SPR) absorption of enlarged AuNPs was found to increase proportional to increasing concentration of H2O2 or glucose. Because of the relatively strong overlap between the SPR absorption of AuNPs (as absorber) and the fluorescence emission of histidine-protected gold nanoclusters (His-AuNCs) (as fluorophore), the fluorescence intensity of His-AuNCs decreased via IFE of AuNPs as the concentrations of H2O2 or glucose increased. This IFE based assay exhibited good performance towards the detection of hydrogen peroxide (over 5–135 μM) and glucose (over 5–125 μM) with detection limits of 3.6 μM and 3.4 μM for H2O2 and glucose, respectively. The method was finally applied to highly selective detection of glucose in urine sample of a diabetes patient.