Synthesis and Characterization of 2-Aminoethylphosphonic Acid-Functionalized Graphene Quantum Dots: Biological Activity, Antioxidant Activity and Cell Viability

Abstract

A facile, environmentally friendly one-step reaction for the preparation of luminescent N-doped graphene quantum dots (GQDs) involving a hydrothermal reaction between citric acid and 2-aminoethylphosphonic acid was designed. Graphene quantum dots were characterized by UV-Vis, FT-IR spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS). Furthermore, the biological activity of the GQDs was studied. UV-Vis spectroscopy studies of the interactions between the GQDs and calf thymus DNA (CT-DNA) showed that the compound interacts with CT-DNA via intercalative binding. DNA cleavage study showed that the GQDs cleaved DNA oxidatively. In addition, antioxidant activity of N-doped GQDs was measured using the DPPH method. As the concentration of the compound increased, the antioxidant activity also increased. According to cell viability analyses results, the N-doped GQDs showed cell viability (70 %) when the concentration reached 228 μg/mL for A549, 200 μg/mL for MDA-MB-231 and 140 μg/mL for NIH-3T3 cell lines with 24 h incubation.