Gold nanocluster-based ratiometric fluorescent probes for hydrogen peroxide and enzymatic sensing of uric acid.
A method is described for ratiometric fluorometric assays of H2O2 by using two probes that have distinct response profiles. Under the catalytic action of ferrous ion, the 615 nm emission of protein-stabilized gold nanoclusters (under 365 nm photoexcitation) is quenched by H2O2, while an increased signal is generated with a peak at 450 nm by oxidizing coumarin with the H2O2/Fe(II) system to form a blue emitting fluorophore. These decrease/increase responses give a ratiometric signal. The ratio of the fluorescences at the two peaks are linearly related to the concentration of H2O2 in the range from 0.05 to 10 μM, with a 7.7 nM limit of detection. The detection scheme was further coupled to the urate oxidase catalyzed oxidation of uric acid which proceeds under the formation of H2O2. This method provides an simple and effective means for the construction of ratiometric fluorometric (enzymatic) assays that involve the detection of H2O2. Graphical abstract Under catalysis by ferrous ion, hydrogen peroxide quenches the luminescence of gold nanoclusters (AuNCs) and oxidizes coumarin into a fluorescent derivative, which rendered fluorescence ON and OFF at two distinct wavelengths for ratiometric measurements.
['Yang|Dongqin|D|', 'Luo|Minchuan|M|', 'Di|Junwei|J|', 'Tu|Yifeng|Y|', 'Yan|Jilin|J|']
D055162:Biocatalysis D015374:Biosensing Techniques D005456:Fluorescent Dyes D006046:Gold D006801:Humans D006861:Hydrogen Peroxide D057230:Limit of Detection D053768:Metal Nanoparticles D014503:Urate Oxidase D014527:Uric Acid
Oxidation Coumarin Urate oxidase Catalysis Fenton reaction Hydroxy radical