In this work, we developed a novel and sensitive label-free sensor for the detection of biological threat-agent anthrax biomarker of dipicolinic acid (DPA) by "off-on" fluorescent carbon dots (CDs)-Cu(II) system. Fluorescent CDs with quantum yield of 24.7% were prepared by a simple one-pot hydrothermal treatment of dopamine in acid condition (pH 5.0) under nitrogen gas. As the prepared CDs have two fluorescent center under a single-wavelength excitation of 315 nm at low concentration, a novel ratiometric fluorescent sensor for the determination of DPA was designed to facilitate self-calibration by using one center as internal reference and another center as signal reporter. The fluorescence of CDs was found to be effectively quenched by Cu(II), and subsequently restored with high sensitivity in the presence of DPA via an “off–on” fluorescence response due to the strong chelate-conjugation between Cu(II) and DPA. Under the optimal conditions, good linearity for DPA detection was obtained over the concentration range from 0.25-20 μmoL/L, with detection limit of 0.079 μmoL/L. The proposed simple, fast and convenient method was applied for DPA detection in different types of environmental water samples and fetal bovine serum sample, and the results are in agreement with results of standard additions in an acceptable recovery range.

Rapid detection of anthrax biomarker based on recovered fluorescence of carbon dots-Cu(II) system

255th National Meeting (2018)

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