Mechanical, microstructural, and rheological characterization of gelatin-dialdehyde starch hydrogels constructed by dual dynamic crosslinking

Novel gelatin/dialdehyde starch (GDS) hydrogels based on gelatin were prepared using dialdehyde starch as a macromolecular crosslinking agent. Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction showed that the dynamic hydrogel network was formed by covalent imine bonds and hydrogen bonds between dialdehyde starch and gelatin. The synergistic physical and chemical cross-linking endowed the hydrogels with excellent mechanical properties (maximum compressive stress was 0.55 MPa), fatigue resistance (they maintained their shape after ten compression cycles), toughness (54.6 kN/m2), and self-recoverability of the polymeric network. In the rheological tests, all the storage modulus were higher than loss modulus, indicating that they are elastic gels and not viscous sols. The polymer network of GDS hydrogels could recover rapidly when subjected to oscillating shear strain. In addition, with increasing dialdehyde starch concentration, the hydrogels had higher swelling stability and a denser microstructure. Given these excellent properties, the hydrogels have potential application prospects as cell culture scaffolds and carriers of bioactive substance.