Novel blue fluorescent carbon dots (CDs-CP) deriving from yeast Cryptococcus podzolicus 5–2 were successfully prepared via a facile and green hydrothermal synthesis method. It exhibited uniform particle size and possessed good excitation-dependent characteristic. The dead bacterial cells were selectively labled by the CDs-CP, but the live ones not, indicating good potential for the live/dead bacterial differentiation. It was found that the prepared CDs-CP showed low biotoxicity and excellent biocompatibility with multicolour fluorescence emission properties, which provided a new insight on the bioimaging application. In addition, the prepared CDs-CP exhibits high selectivity and sensitivity in Ag(I), 2,4-dinitrophenol (2,4-DNP) and 4-nitrophenol (4-NP) detection with excellent linear ranges of 0–15 μM (R² = 0.9945), 0–30 μM (R² = 0.9959) and 0–37.5 μM (R² = 0.9982), respectively. The low detection limits of Ag(I), 2,4-DNP and 4-NP were 113.57 nM, 73.36 nM and 86.47 nM, respectively. It revealed that static quenching mechanism dominated in Ag(I) quenching of the CDs-CP fluorescent, while those of 2,4-DNP and 4-NP were inner filter effect. The fluorescent CDs-CP was successfully applied to determine the Ag(I), 2,4-DNP and 4-NP in real water samples with satisfactory results. Therefore, it is a good candidate for bioimaging application and environmental pollutant detection.

通过简便且绿色的水热合成方法成功制备了源自酵母隐球菌5-2的新型蓝色荧光碳点（CDs- CP）。它表现出均匀的粒径，并具有良好的激发依赖性。死细菌细胞被CDs- CP选择性标记，而活细胞则没有，表明活/死细菌分化的潜力很大。发现制备的CD- CP显示出低的生物毒性和优异的生物相容性以及多色荧光发射特性，这为生物成像应用提供了新的见识。另外，准备好的CD- CP在Ag（I），2,4-二硝基苯酚（2,4-DNP）和4-硝基苯酚（4-NP）的检测中具有很高的选择性和灵敏度，线性范围为 0-15μM （R ² = 0.9945），0 -30μM（R ²  = 0.9959）和0-37.5μM（R ²  = 0.9982），分别。Ag（I），2,4-DNP和4-NP的低检测限分别为113.57 nM，73.36 nM和86.47 nM。结果表明，静态猝灭机理在CDs- CP荧光的Ag（I）猝灭中占主导地位，而2,4-DNP和4-NP的猝灭机理是内滤作用。荧光CD- CP已成功应用于测定实际水样中的Ag（I），2,4-DNP和4-NP，结果令人满意。因此，它是生物成像应用和环境污染物检测的良好候选者。