Kiwi juice stabilized gold nanoclusters for fluorescence turn-on detection of copper ions

Abstract

Gold nanoclusters (AuNCs)-based fluorescent probes with fluorescence turn-on property are necessary to address the challenges in fluorescence turn-off processes for sensing of copper ions (Cu2+) in present. Herein, we described a simple one-step method for fabrication of [email protected] with kiwi juice as both a reducing reagent and a capping ligand, and demonstrated its fluorescent probe's role. With addition of Cu2+, the fluorescence intensity of [email protected]2+ was enhanced obviously. The sensing principle was explored. The charge transfer between surface ligand and Cu2+, and the rigid structure of [email protected]2+ served important roles for monitoring of Cu2+. Then, a fluorescence turn-on protocol was successfully developed for highly selective detection of Cu2+ with a good linear relationship (R2 = 0.992) between the fluorescence intensity and the Cu2+ concentration, ranging from 5.0 µM to 35.0 µM. The limit of detection was 1.6 µM. Furthermore, after intraperitoneal injection, the Cu2+ metabolism process in rats was investigated with the proposed [email protected] as the fluorescent probes. It provides a feasible strategy for preparation of fruit juice protected AuNCs and opens an avenue to realize Cu2+ detection in real bio-samples with the AuNCs as the fluorescence turn-on probes.