In vitro characterization of alginate-chitosan hydrogels prepared with pH modification

Hydrogels are biomaterials frequently used as carrier systems for wound care, tissue engineering, and local drug applications. Our study aimed to prepare and characterize hydrogels using chitosan and sodium alginate through pH modification. Mechanical properties (hardness, adhesiveness, cohesiveness, compressibility, and elasticity), viscosity, surface morphology, and cytotoxicity of polyion complex hydrogels containing different ratios of sodium alginate and chitosan were investigated. Mechanical properties were determined with a texture analyzer. The viscosity values of hydrogels varied between 12235 and 40743.3 cP. Hydrogel samples absorbed water up to 1000 - 1400% of their weight. The effect of pH and polymer concentration on the structural and mechanical properties of alginate-chitosan hydrogels was demonstrated. The findings showed that the decrease in pH improved the mechanical properties of alginate-chitosan hydrogels and increased the viscosity. The concentrations of chitosan and sodium alginate also altered the properties of hydrogels depending on pH. The formulation H5, which had the highest polymer ratio (3%) and lower pH, showed the highest hardness (0.285 +/- 0.018 N), adhesiveness (0.824 +/- 0.042 N. s), and compressibility (1.334 +/- 0.020 N.mm) values. The results showed that the prepared alginate-chitosan hydrogels are not cytotoxic (cell viability of over 80% in L-929 cell line) and safe for use in living organisms.