Abstract
The employment of photoluminescent carbon nanodots (PL-CNDs) in biomedical applications is a new trend of research, specifically in delivering and tracking the drug of interest at the target site. On the other hand, the determination of in vitro and in vivo biocompatibility of the highly utilized nanomaterial is of utmost priority. In the present work, we described the synthesis, optical and surface morphological characterization, and determination of toxicity of PL-CNDs derived from egg white on the in vitro Human Corneal Epithelial (HCE) cells, and in vivo Drosophila melanogaster (D. melanogaster) model. The in-house developed PL-CNDs were blue photoluminescent under excitation at 365 nm and showed an emission peak at 420 nm. Further, HR-TEM analysis suggests the spherical shape of PL-CNDs with a lattice space of 0.26 nm, having a size of 2 nm determined from particle size analysis. The Tauc plot analysis calculated from absorption spectra suggests a band gap of ∼1.8 eV and ∼4.9 eV. The biocompatibility assay (20-250 μg/mL), cell apoptosis (20, 60, 100 μg/mL), and cell morphological (20, 60, 100 μg/mL) studies on HCE cells highlight the cytocompatibility of the PL-CNDs at various concentrations. The toxicity of PL-CNDs was evaluated using an in vivo genetic animal model, D. melanogaster. The oral treatment of 20-250 μg/mL concentrations of PL-CNDs did not induce any significant mortality and climbing defect in flies. In addition, dietary supplementation with PL-CNDs elicits a dose-dependent enhancement of antioxidant defense mechanisms confirmed by SOD and CAT, and the elevation of total antioxidant capacity. The measurement of Reactive Oxygen Species (ROS) in the brain and the gastrointestinal (GI) tract region suggests the non-toxic properties of PL-CNDs (50-100 μg/mL). In summary, PL-CNDs are non-toxic and have good bioavailability, they can be used for delivering drugs in conjugations due to their nano size.
