One-step fabrication of wavelength-tunable luminescence of gold-silver bimetallic nanoclusters: Robust performance for α-glucosidase assay

• DOI: 10.1016/j.snb.2021.130407
• Publication Date: 2021-07-06T03:59:46Z
• Authors: Mengjun Wang; Xiaobin Zhou; Xiyang Wang; Mengke Wang; Xingguang Su
• Keywords: Nanoclusters; Bimetallic strip

Abstract Herein, wavelength-tunable gold/silver bimetallic nanoclusters (Au/Ag NCs) were firstly prepared by using 5-methyl-2-thiouracil (5-MTU) as the reducing and capping agent. Notably, we found that regulating the concentration of 5-MTU could change the emission peak position of Au/Ag NCs. Green-emitting nanoclusters (Au/Ag (g) NCs) were achieved at a relatively low concentration of 5-MTU, whereas continuously increasing the 5-MTU concentration was beneficial to the formation of nanoclusters with intense red-emission (Au/Ag (r) NCs). Owing to the excellent water-solubility and superior stability of the Au/Ag (r) NCs, a sensitive ratiometric fluorescent platform for quantitative analysis of α-glucosidase was developed. In this strategy, a glycine-NaOH buffer was ingeniously adopted to trigger the dopamine (DA) self-polymerize process, which could rapidly generate polydopamine (PDA) with bright fluorescence at 470 nm and efficaciously quench the fluorescence of Au/Ag (r) NCs at 600 nm through photoinduced electron-transfer (PET) effect. By measuring the emission ratio F600/F470, this “off-on-off” sensing strategy exhibited good selectivity and sensitivity toward α-glucosidase ranging from 0.01 to 0.5 U mL−1 with quite a low detection limit (LOD) of 0.007 U mL-1. Additionally, this Au/Ag (r) NCs/PDA-based fluorometric system was utilized for α-glucosidase assay in serum samples with impressively results.