Lysozyme-stabilized gold nanoclusters as a novel fluorescence probe for cyanide recognition

•A novel Lys-AuNCs fluorescence probe for cyanide anion detection was developed.•Lys-AuNCs could be served as a “naked-eye” optical probe for cyanide anion.•The probe was environmentally-friendly and synthesized conveniently.

Lysozyme-stabilized gold nanoclusters (Lys-AuNCs) have been synthesized and utilized as a fluorescent probe for selective detection of cyanide (CN−). Lys-AuNCs had an average size of 4 nm and showed a red emission at 650 nm (λex = 370 nm). The fluorescence of Lys-AuNCs could be quenched by CN−. An excellent sensitivity and selectivity toward the detection of CN− in aqueous solution was observed. The fluorescence intensity was linear with the CN− concentration in the range of 5.00 × 10−6 M–1.20 × 10−4 M with a detection limit as low as 1.9 × 10−7 M. Also, the addition of CN− to Lys-AuNCs could induce an obvious color change from light yellow to colorless. Correspondingly, a bright red fluorescence disappeared and a blue fluorescence appeared. The results indicated that Lys-AuNCs could be applied in detection of cyanide on environmental aspects.

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