Ratiometric Fluorescence Detection Of Cu2+ Based On Carbon Dots/Bovine Serum Albumin-Au Nanoclusters

A ratiometric fluorescence sensor for Cu2+ detection was developed by employing carbon dots (CDs) as the reference fluorophore, and bovine serum albumin (BSA)-Au nanoclusters (AuNCs) both as specific recognition element and as response signal. The CDs were prepared by heating an acetic acid solution of chitosan at 180 degrees C. The proposed nanoprobe was prepared by simply mixing the CDs and BSA-AuNCs. Here, the CDs were associated with BSA-AuNCs to form CDs/BSA-AuNCs nanoprobes based on electrostatic interaction and hydrogen bonds. In the hybrid fluorescent CDs/BSA-AuNCs nanoprobe, the emission of BSA-AuNCs at 640nm was quenched by Cu2+, whereas the emission of CDs at 424nm was maintained. The fluorescence changes of I-640/I-424 had good linearity with Cu2+ concentration in the range 1.5-600nM, and the detection limit of the nanoprobe was 0.5nM for Cu2+ detection, almost 4x10(4) times lower than the maximum allowable amount of Cu2+ in drinking water. The proposed method for detecting Cu2+ also had high selectivity and feasibility.