Synthesis and in vitro Evaluation of Folic Acid-Functionalized Liquid Crystalline Nanoparticles for Enhanced Cytotoxicity in HCT-116 and HT-29 Colorectal Cancer Cells

Background

Colorectal Cancer (CRC) therapy is limited by poor tumor selectivity and systemic toxicity associated with 5-Fluorouracil (5-FU). Liquid Crystalline Nanoparticles (LCNs) offer sustained drug release and improved intracellular delivery, while Folate Receptor (FR)-mediated targeting may further enhance therapeutic specificity. This study aimed to develop and evaluate Folic Acid-Functionalized LCNs (FA-LCNs) loaded with 5-FU, Melatonin (MEL) for improved cytotoxic efficacy against CRC cells.

Materials and Methods

Folic acid was conjugated to Poloxamer 407 (FA-P407) using Carbonyldiimidazole (CDI) mediated coupling and characterized by FT-IR and DSC to confirm amide bond formation. Optimized LCNs and FA-LCNs co-loaded with 5-FU and MEL were prepared using a Design of Experiments (DoE) approach. Physicochemical properties, including particle size, zeta potential, and Polydispersity Index (PDI), were evaluated. In vitro cytotoxicity was assessed in HCT-116 and HT-29 colorectal cancer cells using the MTT assay.

Results

Successful FA conjugation was confirmed by characteristic amide bond formation and altered thermal behavior. LCNs exhibited a particle size of 187.8 nm, which slightly increased to 201.8 nm after folate functionalization, with enhanced surface charge (-48.8 mV) indicating improved stability. FA-LCNs demonstrated significantly enhanced cytotoxicity, reducing IC₅₀ values by approximately 2 to 3 fold compared to free 5-FU, MEL particularly in chemo resistant HT-29 cells.

Conclusion

FA-LCNs significantly enhance the anticancer efficacy of 5-FU, MEL in HCT-116, HT-29 colorectal cancer cells. FA-mediated targeting improves cytotoxic potency against chemo resistant HT-29 cells, suggesting potential utility in overcoming partial drug resistance. However further extensive study warranted to support these findings.