Absence of genotoxicity in mouse brain and hepatic cells following administration of carbon quantum dots derived from the mucilage of Opuntia ficus-indica (L.) Mill.

Abstract

Carbon quantum dots (CQDs) are important nanoparticles because of their fluorescent properties and applications in biomedicine, optronics, and catalysis. In the present report, we synthesized CQDs from the mucilage of Opuntia ficus-indica using the hydrothermal carbonization method. The CQDs showed strong fluorescence a property that may be associated with the presence of hydroxyl, carbonyl, and alkyl groups and electronic transitions including n–π* and π–π*. The size of the CQDs was 4 ± 1.25 nm. In the second step, we determined their genotoxic potential by applying the comet assay on mouse hepatic and brain cells. For this purpose, we administered a single intravenous injection of each of the four tested doses of CQDs (0.02, 0.2, 2.0, and 20.0 mg kg⁻¹), and examined the DNA damage at 3, 6, 12, and 24 h after administration. Besides, we also examined the DNA effect by a visual classification of comets according to their length increase. Our results showed no DNA damage in the brain and liver cells along the experiment, whereas the positive control (methyl methane sulfonate) strongly increased DNA damage in both tissues. Our report supports the use of plant resources to synthetize CQDs, and the suitability of the hydrothermal method for using Opuntia-ficus indica mucilage to obtain non-genotoxic nanoparticles. A finding that upon confirmation of with other genotoxicity assays in other tissues, may suggest the safe application of these nanoparticles for nanobiomedicine and nanotechnology purposes.