D-Penicillamine and bovine serum albumin co-stabilized copper nanoclusters with remarkably enhanced fluorescence intensity and photostability for ultrasensitive detection of Ag+

Copper nanoclusters (CuNCs) have become promising nanomaterials due to their excellent electronic conductivity and biocompatibility. In this study, we reported a facile synthesis of D-penicillamine and bovine serum albumin co-stabilized copper nanoclusters (BSA/DPA-CuNCs) and the use as optical probe for the detection of Ag+. Herein, Cu2+ was reduced into Cu-0 by D-penicillamine, further leading to form DPA-CuNCs. Then, BSA was introduced into DPA-CuNCs to obtain BSA/DPA-CuNCs by their electrostatic attraction. The as-prepared BSA/DPA-CuNCs exhibit remarkably enhanced fluorescence intensity and photostability. The peak fluorescence intensity is more than 2-fold that of DPA-CuNCs. Due to the synergistic effect between DPA and BSA, the nanosensor based on BSA/DPA-CuNCs gives ultrasensitive fluorescence response towards Ag+. Its peak fluorescence intensity linearly decreases with the increase of Ag+ concentration in the range of 1.0 x 10(-8) to 1.0 x 10(-16) M with the detection limit of 4.3 x 10(-17) M (S/N = 3). The method provides the advantage of sensitivity, repeatability and stability. It has been successfully applied in the detection of Ag+ in water samples. The study also opens a new avenue for the fabrication of functional metal nanoclusters that hold great promise in potential applications such as nanosensors, biocatalysts and molecular carriers.