Exploring Carbon Dot Nanoparticles for Imaging and Cellular Interaction in Triple-Negative Breast Cancer

Introduction: Carbon dot nanoparticles (CNDs) are widely regarded as biocompatible agents for cellular imaging due to their strong fluorescence and ease of synthesis. However, their biological effects remain insufficiently characterized. Methods: We synthesized carbon nanodots (E-CNDs) using a microwave-assisted method with citric acid and ethylenediamine. Their intracellular distribution and potential impact on triple-negative breast cancer (TNBC) cells were investigated. Results: After 16 hours of incubation with E-CNDs (up to 0.8 mg/mL), imaging revealed strong perinuclear localization, moderate mitochondrial presence, and no detectable nuclear signal. These observations supported their use in intracellular imaging and motivated further analysis of their biological effects. While CCK-8 assays showed no significant cytotoxicity across concentrations, molecular analysis revealed dose-dependent downregulation of glucose-6-phosphate dehydrogenase (G6PDH) and upregulation of procaspase 3, aligning with increased apoptotic activity detected by Annexin V/PI staining. Conclusion: These results show that although E-CNDs appear non-toxic by standard viability assays and function effectively as imaging agents, they also trigger measurable molecular and apoptotic responses. This underscores that cell viability alone is insufficient to assume biocompatibility. More detailed molecular and functional assessments are needed to establish reliable safety profiles, which are critical for the safe design and evaluation of nanomaterials in biomedical applications.