Preparation Of Proportional Gold Nanoclusters And Detection Of Biomolecules And Metal Ions

As a new type of fluorescent nanomaterial,gold nanoclusters have been widely used in biochemical,environmental,medical and food fields for their superior biocompatibility,fluorescent properties and small size.However,it still faces the problem that single-emission fluorescent probes are easily affected by the probe concentration or external environment,so it is especially important to construct a ratiometric fluorescent probe by combining gold nanoclusters with other fluorescent materials.The easy preparation and modification of gold nanoclusters also allow them to be easily modified to improve their luminescence properties and use in detection.Based on this,we constructed two ratiometric fluorescent probes based on GSH-Au NCs and BSA-Au NCs,and detected phenylalanine,Fe3+and uric acid in human blood,respectively.A novel dual-emissive gold nanoclusters（d-Au NCs）was prepared based on GSH-Au NCs,which show two unique emission peaks at 420 nm and 600 nm under single-wavelength excitation.d-Au NCs have completely different spectral responses to phenylalanine and Fe³⁺with high contrast.The d-Au NCs have completely different spectral responses to phenylalanine and Fe³⁺with high contrast,well avoiding signal fluctuations.Phenylalanine turns on the red emission of the probe,while Fe³⁺turns on its yellow emission and turns off the red emission.The d-Au NCs showed good selectivity for phenylalanine and Fe³⁺by detecting a wide range of amino acids and metal ions.Finally,the method was applied to the determination of phenylalanine and Fe³⁺in lake water,human urine and milk,which has promising applications in biological and environmental fields.Ag was doped onto BSA-Au NCs to prepare BSA-Au/Ag NCs ratiometric fluorescent probes for the highly sensitive detection of H₂O₂ and uric acid.The oxidation of o-phenylenediamine（OPD）by H₂O₂ to its corresponding oxidation product（OX OPD）catalyzed by horseradish peroxidase（HRP）reduced the fluorescence peak of BSA-Au/Ag NCs at 625 nm and accompanied by a new fluorescence peak at 580 nm.This method can be further applied to the detection of uric acid,both with good selectivity,since uric acid is specifically generated by the catalytic action of uricase as H₂O₂.The spiked recovery of uric acid in blood samples was also investigated,demonstrating the great potential of the method for the detection of uric acid in clinical blood samples.The sensing strategy provides a high-throughput detection platform for reactants involving the generation of H₂O₂.It provides a good theoretical basis and methodological guidance for further clinical analysis.