Physicochemical properties and cytotoxicity of carbon dots in grilled fish
In recent years, the presence of food-borne nanoparticles during food processing has been a controversial issue. In this paper, we introduced a class of extremely low-cytotoxicity carbon dots (CDs) extracted from grilled pike eel which have been consumed for thousands of years. These CDs are water-soluble, quasi-spherical, and nanosized (approximately 2.75 nm). UV illumination can excite CDs to emit a strong sapphire luminescence with a quantum yield as high as 68.7%. X-ray diffraction (XRD) analysis showed that these nanoparticles are amorphous attributed to the disordered carbon atoms. X-ray photoelectron spectroscopy (XPS) measurements showed that the CDs contain a predominant C1s peak at 284.43 eV and an O1s peak at 531.35 eV accompanied by a pronounced N1s peak at 399.34 eV, with the atomic percentages of 66.58%, 17.5% and 15.91%, respectively. Moreover, the CDs also have excellent biocompatibility and could ease into the cytoplasmic region of MC3T3-E1 cells without any seriously imposed toxicity against cells.