Evaluation of biopolymer-derived carbon dots as cancer diagnostic biomarkers for human monocyte cell lines (THP-1)

Abstract

Fluorescent carbon dots (C-dots) were fabricated from Anogeissus latifolia (Gum ghatti) gum extract using direct microwave pyrolysis method. The C-dots are fine-tuned concerning three parameters, viz., NaOH addition (presence and absence), microwave power, and irradiation time. C-dots optical properties were investigated through UV–visible (UV–Vis) and fluorescence spectroscopy. Using field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and Raman Spectroscopy, physiochemical properties of synthesized C-dots were inspected. The average size of C-dots was estimated to be 4.8 ± 2 nm and is amorphous. These C-dots displayed high solubility in an aqueous medium due to oxygen functionality, and showed good fluorescence stability to high-ionic concentration and varied pH. The fluorescence spectra outcomes specified that C-dots exhibited excitation-dependent emission behavior. Furthermore, the C-dots biological function was tested for cell biocompatibility and bioimaging. The cytotoxicity studies were performed on Vero cell lines and compared with THP-1 human monocyte cell lines at different concentrations. The results revealed good biocompatibility app. 80 and 90% for Vero and THP-1 cell lines even after 24 h incubation with the C-dots. Finally, by employing C-dots as the fluorescent tool, THP-1 cells were imaged successfully via a Confocal Laser Scanning Microscope (CLSM) in a concentration-dependent manner.