Design of catechin-based carbon nanodots as facile staining agents of tumor cells

Carbon nanodots (CNDs) have widely received great attention as a result of favorable optical, electrical, optoelectrical, biocompatible, and non-toxic properties that these nanoparticles possess. However, the exploration of nanoparticles from natural raw material is still limited. In the present work, carbon dots were produced from catechin isolated from Uncaria gambir through a simple and facile process. Carbon nanodots were produced by the pyrolysis process of catechin, which allowed it for carbonization. Owing to its unique properties, such as photoluminescence with an emission peak at 500 nm (λ_ex = 380 nm), average size diameter of about 5 nm and non-toxic properties, Cat-CNDs were incredibly potential for staining targeted tumor cells. The staining ability shown by confocal microscopy observations showed their green fluorescence images which meant that the CNDs easily penetrated HeLa cells via endocytosis. The resulting CNDs which were analyzed using several significant techniques proved that the prepared Cat-CNDs were tremendously dispersible and water-soluble, had good colloidal stability, excellent biocompatibility, favorable hydrophilicity, high photostability, and were non-toxic.