Heteroatom doping and supramolecular assembly promoted copper nanoclusters to be a stable & high fluorescence sensor for trace amounts of ATP determination

Abstract

The glutathione-capped bimetallic copper and gold nanoclusters (CuAuNCs@GSH) were achieved through Au doping into the unstable copper nanoclusters (CuNCs@GSH), which induced the photoluminescence stabilization time increase from 4 to 7 days. Moreover, the Ce3+ introduction further significantly increased the stable storage time (from 7 to 25 days) and the emission intensity (near 140-fold), accompanying a quantum yields enhancement from 0.30% to 22%. Transmission electron microscopy (TEM) revealed the Ce3+-induced larger assemblies of CuAuNCs-Ce3+ from monodispersive CuAuNCs@GSH nanodots. The fluorescence enhancement was attributed to the aggregation-induced emission (AIE) property of CuAuNCs@GSH, where Ce3+ was bound to the ligands GSH and reduced the non-radiative relation of the excited states. Besides, the strong interaction between ATP and Ce3+ dissociated the CuAuNCs-Ce3+ assembly into monodisperse nanoclusters and recovered the weak luminescence. Therefore, the CuAuNCs-Ce3+ assembly was applied to determine ATP, which exhibited high selectivity and sensitivity with a detection limit of 53 nM. Finally, the method was successfully applied to determine ATP in diluted serum with very high recovery. Therefore, the present study provides an efficient way to improve the fluorescence properties of metal nanoclusters and supplies a selective and sensitive ATP sensor.