A novel and convenient near-infrared fluorescence "turn off-on" nanosensor for detection of glucose and fluoride anions.

In this paper, 3-aminobenzeneboronic acid functionalized CuInS2 quantum dots (APBA-CuInS2 QDs) were prepared and utilized as a near-infrared fluorescence nanosensor for the detection of glucose and fluoride anions. The APBA-CuInS2 QDs had a symmetric fluorescence emission centered at 742nm that was in the near-infrared spectral region. The APBA functional groups, which were reactive toward vicinal diols, could covalently bridge the glucose molecule and induced the initial dispersed APBA-CuInS2 QDs aggregate to form a large assembly, leading to the fluorescence of APBA-CuInS2 QDs turned off via the surface quenching states induced mechanism. When fluoride anions were added into the APBA-CuInS2 QDs/glucose system, the assembly was destroyed and as a result the quenched fluorescence dramatically turned on. The proposed nanosensor could be used for glucose detection in the concentration range of 0.005-8mmolL(-1) with a detection limit of 1.2μmolL(-1). The linear range for fluoride anions was 0.1-700μmolL(-1) with a detection limit of 0.029μmolL(-1). Furthermore, the feasibility of the proposed nanosensor in real samples assay was also studied and satisfactory results were obtained.