Chitosan/β-cyclodextrin nanocarriers enhance 5-fluorouracil efficacy against colorectal cancer via pH-responsive release and apoptosis modulation

Figures

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  Fig. 1. Schematic illustration of the preparation of (A) 5-fluorouracil/β-cyclodextrin (5-FU/β-CD) via co-evaporation method, (B) chitosan/β-cyclodextrin (Chs/β-CD) pseudopolyrotaxane complex via physical mixing method and (C) ternary 5-fluorouracil/chitosan/β-cyclodextrin (5-FU/Chs/β-CD) formulation via solvent evaporation/co-precipitation method. Created with BioRender.com .

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  Fig. 2. XRD patterns of pure 5-FU, 5-FU/β-CD inclusion complex, and 5-FU/Chs/β-CD pseudopolyrotaxane.

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  Fig. 3. Dynamic light scattering (DLS) characterization of free 5-FU, binary 5-FU/β-CD inclusion complex, and ternary 5-FU/Chs/β-CD formulation. (A) Intensity-based particle size distribution profiles of free 5-FU, binary 5-FU/β-CD complex and ternary 5-FU/Chs/β-CD formulation. (B) Zeta potential distributions of free 5-FU, binary 5-FU/β-CD complex and ternary 5-FU/Chs/β-CD formulation. All measurements were performed in triplicate at 25 °C. Data represent mean ± SD (n = 3).

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  Fig. 4. Scanning electron micrographs of (A) pure 5-fluorouracil (5-FU), (B) binary 5-FU/β-cyclodextrin (β-CD) inclusion complex, and (C) ternary 5-FU/β-CD/chitosan (Chs) nanocarrier complex. The images taken at the same scale (1 μm) and magnification (10,000×).

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  Fig. 5. FTIR spectra of pure 5-FU, 5-FU/β-CD inclusion complex, and 5-FU/Chs/β-CD pseudopolyrotaxane.

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  Fig. 6. Phase solubility study of 5-FU at 25 °C after 72 h equilibration. (A) Phase solubility diagram of 5-FU in β-CD solutions. (B) Phase solubility diagram of 5-FU in Chs/β-CD pseudopolyrotaxane solutions.

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  Fig. 7. In vitro Cumulative release profiles of 5-FU from the 5-FU/Chs/β-CD ternary formulation at 37 °C in PBS (pH 7.4) and acetate buffer (pH 5.5).

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  Fig. 8. Dose–response cytotoxicity curves of free 5-FU, 5-FU/β-CD inclusion complex, and 5-FU/Chs/β-CD pseudopolyrotaxane against HCT-116 colorectal cancer cells after 72 h of treatment.

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  Fig. 9. Microscopic images of HCT-116 colorectal cancer cells after 72 h of treatment with 5-FU, 5-FU/β-CD inclusion complex, and 5-FU/Chs/β-CD pseudopolyrotaxane with two concentrations (0.05 and 500 µM).

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  Fig. 10. Fold‑change expression of Caspase‑3 (A), P53 (B), BCL2 (C), and VEGF (D) in HCT‑116 colorectal cancer cells treated with 5‑FU, 5‑FU/β‑CD, or 5‑FU/Chs/β‑CD compared to untreated control. Different superscript letters indicate significant differences between groups (p < 0.05).

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  Fig. 11. Differential gene expression analysis of GSE183977 (control vs. treated). (A) Volcano plot. (B) MA plot. (C) Boxplots of normalized expression values.

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  Fig. 12. Protein–protein interaction (PPI) network of 250 dysregulated genes from STRING analysis, comprising 112 nodes and 170 edges (P < 1.0 × 10− 16).