Mutually reinforced multicomponent polysaccharide networks

Networks made from chitosan and alginate have been utilized as prospective tissue engineering scaffolds due to material biocompatibility and degradability. Calcium (Ca 2+ ) is often added to these networks as a modifier for mechanical strength enhancement. In this work, we examined changes in the bulk material properties of different concentrations of chitosan/alginate mixtures (2, 3, or 5% w/w) upon adding another modifier, chondroitin. We further examined how material properties depend on the order the modifiers, Ca 2+ and chondroitin, were added. It was found that the addition of chondroitin significantly increased the mechanical strength of chitosan/alginate networks. Highest elastic moduli were obtained from samples made with mass fractions of 5% chitosan and alginate, modified by chondroitin first and then Ca 2+ . The elastic moduli in dry and hydrated states were (4.41 ± 0.52) MPa and (0.11 ± 0.01) MPa, respectively. Network porosity and density were slightly dependent on total polysaccharide concentration. Average pore size was slightly larger in samples modified by Ca 2+ first and then chondroitin and in samples made with 3% starting mass fractions. Here, small‐angle neutron scattering (SANS) was utilized to examine mesh size of the fibrous networks, mass‐fractal parameters and average dimensions of the fiber cross‐sections prior to freeze‐drying. These studies revealed that addition of Ca 2+ and chondroitin modifiers increased fiber compactness and thickness, respectively. Together these findings are consistent with improved network mechanical properties of the freeze‐dried materials. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 840–851, 2011.