Synthesis of cationic carbon dots and their effects on human serum proteins and in vitro blood coagulation

Cationic carbon dots (CCDs) are a promising alternative to gene-delivery systems, and good biosafety levels are crucial for their in vivo use. In this study, spherical and monodispersed CCDs with an average surface potential of +28.7 mV were prepared using sucrose and glutamate (denoted SG-CCDs) using a one-pot autoclave-assisted method. Molecular interactions between the SG-CCDs and four major human serum proteins (albumin, immunoglobulin G, fibrinogen, and transferrin) were investigated. The results were further verified on human serum, and the effect of the SG-CCDs on in vitro blood coagulation was examined. The results showed that the fluorescence of human serum was clearly quenched by the SG-CCDs through a dynamic collision mechanism. Moreover, SG-CCDs at a concentration of 20 μM exhibited minor effects on the secondary structure of human serum. The activated partial thromboplastin and prothrombin time as well as the fibrinogen concentration were not changed, indicating that the SG-CCDs did not interfere with the coagulation process. This study provided an understandable background on the behaviour of CCDs in clinical applications.