Biomimetic Polyelectrolyte Complexes as Delivery Systems for Phytic Acid

In this study, different chitosan–alginate polyelectrolyte complexes (PECs) were investigated as a biomimetic delivery system for phytic acid (PA), a natural antioxidant with potential anticancer activity. Physicochemical characterization, including ATR-FTIR, SEM/EDX, swelling analysis, and PA release profile, demonstrated that the polymer ratio strongly influenced film morphology, stability, and PA binding. Crosslinking generally produced smoother, more compact surfaces and resulted in reduced swelling capability, particularly in alginate-rich systems. PA release in normal saline varied significantly across formulations, with the 5:1 and 1:2 ratios releasing the highest amounts after seven days as a result of higher PA content. The stability tests exhibited strong ratio-dependent degradation, with the 1:1 films remaining the most stable across all tested media. Chitosan-rich films showed moderate mass loss (up to ~25%), whereas alginate-rich films, such as the 1:5 films, disintegrated due to excessive swelling and possibly weak interactions between polymer chains. PA-crosslinked samples exhibited similar trends; alginate-rich films lost up to 60–65% of their mass, while chitosan-rich samples demonstrated that a higher chitosan content produces more stable complexes, indicating a preferable interaction between PA and chitosan. Cytotoxicity assays using MG-63 osteosarcoma and HDFa fibroblast cells revealed dose-dependent effects. While PA-free materials did not affect the viability of either cell type, extracts of PA-crosslinked films at the highest concentration reduced the viability of MG-63 and HDFa cells. Importantly, moderate concentration of PA-crosslinked film extracts affected only MG-63 cells without harming fibroblasts, potentially suggesting mild preferential activity. Overall, the results demonstrate that PA-crosslinked PEC films provide a tunable, biomimetic platform with structural, physicochemical, and biological properties that can be modulated by adjusting the polymer ratio. The combination of enhanced stability, controlled PA release, and dose-dependent cytotoxicity offers potential for further development as antitumor materials.