Receptor-mediated delivery of berberine via folic acid-based carbon dots: A novel strategy for targeted ovarian cancer therapy

The folic acid (FA) receptor is frequently overexpressed in ovarian cancer cells, making it an attractive target for receptor-mediated drug delivery. Carbon dots (CDs), a class of fluorescent nanoparticles, offer strong potential as nanocarriers due to their biocompatibility, high solubility, ease of functionalization, and traceability of cellular uptake. Berberine (BBR), an isoquinoline alkaloid with known anticancer properties, suffers from poor solubility and limited cellular uptake. This study aimed to develop FA-based CDs (FA-CDs) as a targeted delivery system for BBR to enhance its therapeutic efficacy against ovarian cancer cells. FA-CDs were synthesized via a solvothermal method using folic acid and citric acid in dimethylformamide (DMF). The nanoparticles were characterized for size, surface charge, topology, and functional groups using FTIR, H-NMR, DLS, and Raman spectroscopy. BBR was electrostatically loaded onto FA-CDs (designated FA-CD-BBR), and drug loading efficiency/content were quantified spectrophotometrically. Cytotoxicity was assessed by MTT assay on OVCAR3 (human) and ID8 (mouse) ovarian cancer cell lines. Human foreskin fibroblasts (HFF) and mouse embryonic fibroblasts served as normal controls, while A549 lung cancer cells lacking FA receptors were used to test targeting specificity. Cellular uptake was evaluated using confocal microscopy. The synthesized FA-CDs were under 5 nm in size, blue-emitting, and negatively charged. FTIR and H-NMR confirmed the presence of key functional groups—particularly carboxyl and aromatic groups—that are critical for folate receptor binding. Raman spectroscopy revealed an amorphous carbon structure. MTT assays showed that FA-CD-BBR exhibited significantly greater cytotoxicity compared to free BBR in OVCAR3 cells (IC?? = 33.7 μM vs. 70 μM) and ID8 cells (IC?? = 9.1 μM vs. 502 μM). Moreover, FA-CD-BBR exhibited lower toxicity in normal cells and no cytotoxic effect on FA receptor-negative A549 cells, confirming receptor-specific targeting. Confocal microscopy showed strong uptake of the FA-CDs in cancer cells. Our results showed that FA-based CDs efficiently enhanced the targeted delivery and cytotoxic effect of BBR in ovarian cancer cells expressing FA receptors, while minimizing off-target toxicity. These results support FA-CDs as a promising nanocarrier system for selective anticancer drug delivery.

Dr. Ghamartaj Hossein studied Biology and earned her Ph.D. in the field of reproductive biology in 1997 working on heparin sulfate proteoglycans role in ovulation events at the Geneva University and performed a Postdoc in cancer biology in the Department of Morphology, C.M.U, Geneva, Switzerland. Then worked as a medical advisor in an international pharmaceutical company in the field of fertility. She works as an Associate Professor of Developmental Biology at the School of Biology, College of Science, University of Tehran, Iran since 2005. Dr. Hossein’s research interests are deciphering the role cancer related-signaling pathways involved in ovarian cancer progression.