Facile hydrothermal synthesis of nitrogen, phosphorus-doped fluorescent carbon dots for live/dead bacterial differentiation, cell imaging and two nitrophenols detection

The blue fluorescent nitrogen, phosphorus doped 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 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. Schematic of the synthetic route for fluorescent Tg N,P-CDs and the applications in live/dead microbial differentiation, cell imaging, 2,4-DNP and 4-NP detection. [Display omitted] •The novel nitrogen, phosphorus-doped CDs deriving from Thelephora ganbajun Zang were prepared by hydrothermal method.•The Tg N,P-CDs possessed a good potential for live/dead bacterial differentiation and cell imaging.•The Tg N,P-CDs exhibited high selectivity and sensitivity in 2,4-DNP and 4-NP detection.