Facile Hydrothermal Synthesis of Nitrogen, Phosphorus-doped Fluorescent Carbon Dots for Live/Dead Bacterial Differentiation, Cell Imaging and Two Nitrophenols Detection

Abstract The blue fluorescent nitrogen, phosphorus carbon dots (Tg N,P-CDs) deriving from Thelephora ganbajun Zang were successfully obtained by hydrothermal method. Tg N,P-CDs possessed excellent fluorescence features and displayed strong blue fluorescence emission at 444 nm under 356 excitation with good water solubility. Tg N,P-CDs exhibited low biotoxicity and excellent biocompatibility by live/dead bacterial differentiation, cell imaging and onion epidermal staining. Furthermore, the nanoprobes showed high selectivity and sensitivity in detecting 2,4-dinitrophenol (2,4-DNP) and 4-nitrophenol (4-NP), and excellent linear range of 0-50 μM (R2=0.9923) and 0-50 μM (R2=0.9926) with low detection limits of 35.09 nM and 78.62 nM for 2,4-DNP and 4-NP, respectively. The Tg N,P-CDs was successfully applied to determine the 4-NP and 2,4-DNP in real water and soil samples. It revealed that the inner filter effect quenching mechanism dominated in quenching of Tg N,P-CDs fluorescent by 2,4-DNP and 4-NP. It provides a new insight on the bioimaging application and environmental pollutant detection.