Physicochemical characterization, biodistribution, and bio‐effects of fluorescent carbon dots from roasted Spanish mackerel

Abstract

Nanoparticles with small sizes formed in the process of food thermal treatment have gained substantial attention due to their safety uncertainty and latent risks to human health. Herein, the physicochemical features of fluorescent carbon dots (CDs) from roasted Spanish mackerel were studied, it was found that the size distribution, fluorescence properties, surface groups, and formation process of CDs were highly dependent on the roasting time of Spanish mackerel. The interaction of CDs with digestive proteases resulted in the structural change and activity inhibition of proteases. When the concentration of CDs was 120 μg mL−1, the enzyme activity of pepsin and trypsin was reduced from 100% to 75.95% and 78.5%, respectively. The CDs caused static fluorescence quenching of pepsin and trypsin as confirmed by the fluorescence analysis. After oral administration, CDs can be transported to the main organs through the blood. The cytotoxicity assessment revealed that the cell viability decreased with the prolonging of roasting time. The CDs roasted at 230°C for 40 min showed a significant hemolytic effect even at a low concentration of 0.5 mg mL−1. Moreover, the cellular uptake level and pathway of CDs were significantly affected by blood protein adsorption. This study helps to evaluate the in vivo biodistribution, the interaction with proteases during gastrointestinal digestion, and the cellular uptake of CDs after transport through the blood, providing a theoretical basis for revealing the potential effects of foodborne nanoparticles.