Easy synthesis, characterization and cell cytotoxicity of green nano carbon dots using hydrothermal carbonization of Gum Tragacanth and chitosan bio-polymers for bioimaging

Two environmentally friendly biopolymers, Gum Tragacanth and Chitosan, were used for one-step synthesis of photo-luminescent nano carbon dots using hydrothermal carbonization technique. In this study, free Gum Tragacanth and also in combination with chitosan are used as the carbon sources for preparing of nano carbon dots. The morphological aspects and chemical compositions of prepared carbon dots were characterized using various techniques such as Fourier transform infrared, dynamic light scattering, UV-visible, X-ray diffraction method, atomic force microscope and cyclic voltammetry. The Gum Tragacanth /chitosan and Gum Tragacanth based carbon dots have favorable luminescent properties and exhibited good photo-stability. As indicated by different spectroscopic and microscopic methods, the GT and GT/chitosan based carbon dots possesses excellent solubility as a result of many hydrophilic groups on the surface and good photo-stability. The obtained nano carbon dots include a large number of surface functionalized groups. Their excellent biocompatibility and low cytotoxicity has been confirmed using MTT assay. Also, the cellular uptake studies show that the Gum Tragacanth/chitosan based carbon dots were directly internalized into the cells more than other nano carbon dot. These results indicated that owing to the excellent features of the generated carbon dots based on bio-polymer, they can be used, as ideal non-toxic markers, in bio-sensing, biological labeling, medical diagnostics, optoelectronic devices and bio-imaging.