Fabrication, Characterization and Evaluation of Gallic Acid-Encapsulated Curdlan Gum Nanoparticles with Potential Application for Breast Cancer Treatment

Curdlan gum (CG) is a β-(1→3)-linked glucan insoluble exopolysaccharide produced by marine bacteria Enterobacter cloacae subsp. dissolvens RSW2n. In this study, CG was used to fabricate gallic acid-encapsulated curdlan gum nanoparticles (GA-CG NPs) for effectively delivering the drug into breast cancer cells (MCF-7) using glutaraldehyde as the crosslinking agent and a modified desolvation method was adopted. The fabricated GA-CG NPs were characterized by UV–Visible spectra, FT-IR, XRD, particle size analyzer and HR-TEM. The stability of GA-CG NPs was evaluated at various pH and simulated body fluids. In vitro drug release and its kinetics were examined through the dissolution mechanism using mathematical prediction models. The encapsulation efficiency and loading capacity of gallic acid was 88.215 ± 3.242% and 8.26 ± 0.021%, respectively. The antioxidant and cytotoxic potential of GA-CG NPs were evaluated through in vitro assays. The IC₅₀ of GA-CG NPs against MCF-7 cells was found to be 16.75 µg × mL⁻¹. The induction of apoptosis in MCF-7 cells was confirmed through flow cytometry. Nuclei condensation, loss of mitochondrial membrane potential, and deformed cell membranes were visualized by staining. Curdlan gum effectively controls the release of gallic acid as the gel matrix slowly degrades and releases the encapsulated gallic acid. Hence, the curdlan gum produced by E. cloacae could be considered as promising candidate for drug delivery application for degenerative disorder.