Hydrothermal synthesis of Auricularia auricula derived nitrogen, phosphorus-doped carbon dots and application in Ag(I) and 4-nitrophenol detection and bioimaging

Novel fluorescent nitrogen and phosphorus-doped carbon dots (Aa N,P-CDs) derived from Auricularia auricula were successfully prepared via a simple hydrothermal method. The Aa N,P-CDs showed high selectivity and sensitivity in detection of 4-nitrophenol (4-NP) and Ag(I) and good linear ranges of 4-NP (0–37.5 μM, R2 = 0.9967) and Ag(I) (0–25 μM, R2 = 0.9934). The low detection limits were 198 nM and 74.35 nM, respectively. This showed that static quenching dominated in Ag(I) quenching of the Aa N,P-CD fluorescence, while that of 4-NP was the inner filter effect. The Aa N,P-CDs were successfully used to detect 4-NP and Ag(I) in real water and soil samples. Cell imaging indicated that Aa N,P-CDs showed low biotoxicity and good biocompatibility, which provided a new insight into bioimaging application and environmental pollutant detection.