Abstract: Carbon quantum dots (CQDs) formed during food processing may cause potential health risks. In this study, CQDs from boiled scallop were characterized systematically. The CQDs were roughly spherical in appearance and well dispersed as observed in transmission electron microscopic images. The average diameter of the CQDs was around 3.7 nm. The presence of hydroxyl, amino, and carboxyl groups on the CQDs surface was demonstrated by Fourier transform infrared and X-ray photoelectron spectroscopy. The interaction of the CQDs with cadmium was investigated by isothermal titration calorimetry (ITC), and the results revealed electrostatic interaction to be the predominant driving force for the binding between cadmium and the CQDs. In addition, the combined toxicity of the CQDs and cadmium was investigated. The results suggested combination with the CQDs increased the toxicity of cadmium by enhancing reactive oxygen species production and mitochondrial membrane damage, disturbing the cell cycle. This study provides useful information for understanding the properties of foodborne nanoparticles.

Key words: carbon quantum dots; cadmium; scallop; combined toxicity