| dcterms.abstract | Alginate-based hydrogels have emerged as a promising biomaterial for applications in tissue engineering because they are biocompatible, mucoadhesive, and non-immunogenic. However, the nanoscale and microscale structure, transport characteristics, and mechanical properties that can be achieved with conventional alginate gels are somewhat limited. Multicomponent hydrogels have been explored as one means to improve the properties of conventional hydrogels, which usually consist of a single polymer network. In this work, we report the structural and mechanical properties of a new type of nanocomposite hydrogel, consisting of varying concentrations of the biopolymer alginate and synthetic silicate nanoparticles, together with a temperature-sensitive poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymer. The gels were prepared using physical association and studied using rheology, differential scanning calorimetry, and small-angle neutron scattering (SANS). The interaction between the components appear to be synergistic; that is, the resulting multicomponent hydrogels are much more elastic than the individual components. For example, the storage modulus, G', of one series of the nanocomposite gels containing the PEO-PPO-PEO copolymer is 96 times that of its respective control containing only alginate and nanoparticles. A 20-40x enhancement in G’ is observed at temperatures between 30°C and 55°C. SANS data are in agreement with rheology data and shows that the block copolymer dominates the nanoscale structure, while alginate concentration does not seem to significantly affect the scattering. The scattering data was analyzed qualitatively and quantitatively fit to the power law and to the Teubner-Strey models to better understand the hydrogel network structure. | |
