Facile synthesis of orange fluorescence multifunctional carbon dots for label-free detection of vitamin B12 and endogenous/exogenous peroxynitrite

In this work, orange emission fluorescent multifunctional carbon dots (O-CDs) were designed for the label-free detection of vitamin B-12 (VB12),endogenous/exogenous peroxynitrite (ONOO) sensing, cell imaging, and fluorescent flexible film preparation. The O-CDs with excitation-independent were prepared using safranine T and ethanol as precursors via one-step hydrothermal process. VB12 was utilized as a quencher to quench the fluorescence of O-CDs due to the internal filtration effect (IFE). Two-segment linear ranges are 1-65 mu M and 70-140 mu M, and the detection limit was calculated as 0.62 mu M. Besides, ONOO can reduce the fluorescence intensity of O-CDs based on static quenching (SQ). The linear ranges are 0.3-9 mu M and 9-48 mu M, and the detection limit was 0.06 mu M. Moreover, the O-CDs were exploited as a cellular imaging reagent for intracellular VB12 and endogenous/exogenous ONOO imaging owing to its great biocompatibility, low toxicity and strong photostability. These results indicate that O-CDs have the potential to be used as a sensitive fluorescence probe to rapidly monitor VB12 and endogenous/exogenous ONOO with high selectivity in living cells. Also, the as-proposed O-CDs can be employed to fabricate O-CDs/PVA composites as fluorescent flexible films. All of the above prove that the O-CDs present great prospect in multiple applications such as biosensing, cellular labeling, biomedical optical imaging, and fluorescent films.

Automated summary

In this work, orange emission fluorescent multifunctional carbon dots (O-CDs) were designed for label-free detection of VB12, ONOO sensing, cell imaging, and fluorescent flexible film preparation. O-CDs showed high detection sensitivity and biocompatibility, presenting great potential for various applications.