Comparative study of three viscosity-enhancing strategies for chitosan-alginate composite hydrogels

Despite the widespread use of chitosan-alginate hydrogels in biomedicine, their limited adhesive properties hinder wound dressing applications. This study aimed to compare three strategies of viscous chitosan-alginate composite hydrogels preparation. Chitosan-alginate composite hydrogels were prepared by using chitosan and sodium alginate as raw materials. Three approaches were systematically compared: (1) dopamine incorporation, (2) replacing alginate with catechol oxidized sodium alginate, and (3) carrageenan addition. The structure, morphology, and viscosity of the produced hydrogels were also characterized. The comparison of three methods revealed that the dopamine-modified hydrogel exhibited superior viscosity (1500 mPa·s), representing a 3-fold increase over the control. Swelling tests verified that all modified hydrogels had lower equilibrium swelling ratios (837.3% ~ 1047.1%) than the neat C-A hydrogel (1220.9%), proving enhanced crosslinking networks, while contact angle results confirmed that carrageenan incorporation greatly improved the surface hydrophobicity of the hydrogel, which contributed to its superior adhesive performance. This study provides a methodological reference for preparing viscous hydrogels and make it possible for applications in biomedical fields. These findings establish an optimized protocol for fabricating adhesive hydrogels with potential for clinical translation in moist wound management.