Preparation of novel fluorescent probe based on carbon dots for sensing and imaging Fe(III) and pyrophosphate in cells and zebrafish.

Ferric ions (Fe3+) and pyrophosphate anions (PPi) are involved in many physiological processes and play important roles in biological systems. The abnormal level of Fe3+ and PPi will cause serious damage to the environment and life. At present, the application of such probes in life, especially in vivo, is still very scarce. So, the development of a fluorescent probe to simultaneously detect Fe3+ and PPi has great significance to the health of the environment and organisms. Herein, nitrogen-doped carbon quantum dots (N-CDs) were synthesized via solvothermal treatment, using biuret and citric acid as precursors. The synthesized N-CDs showed highly selective and sensitive detection of Fe3+ through a photoluminescence quenching effect. The fluorescence of N-CDs quenched by Fe3+ could be restored with PPi, rendering the N-CDs/Fe3+ sensor promising for PPi detection ('OFF-ON'). The linear ranges of detection for Fe3+ and PPi were 3-30 and 2-12 μM, and the limits of detection were 2.71 and 1.12 μM, respectively. The practical applications of N-CDs were tested using tap water samples. Furthermore, N-CDs can be used for the detection and imaging of Fe3+ and PPi in HeLa cells and zebrafish owing to their excellent optical properties.