Design, characterization and evaluation of homogeneous oxidized sodium alginate/polyacrylamide–gelatin composite hydrogels constructed via interpenetrating network technology

To improve the bio-applicability of alginate hydrogels, a combination of interpenetrating network technology, oxidation of alginate, surface coverage of gelatin and endogenous crosslinking of hydroxyapatite/ d -glucono- δ -lactone complex was designed to construct homogeneous oxidized sodium alginate/polyacrylamide–gelatin (OSA/PAM-GT) composite hydrogels. The effects of mass ratio of PAM chemical crosslinked networks and OSA ionic crosslinked networks on the microscopic morphology, mechanical properties, swellability, biodegradability and biocompatibility of the composite hydrogels were comparatively studied. Experimental results showed that porous OSA/PAM-GT composite hydrogels with regular morphology can be prepared through the interpenetration of OSA ionic crosslinked network and PAM chemical crosslinked network via hydrogen bonds and Schiff bases, which not only enhanced the mechanical properties and thermal stability of the composite hydrogels, but also regulated their swelling and in vitro biodegradability. When the mass ratio of OSA to PAM was 1:2, the cell proliferation activity on OSA/PAM-GT composite hydrogels was the best, but excessive PAM reduced the living space of cells and hindered their growth due to the reduction of porosity. Considering the results obtained, interpenetrating network technology in combination with surface coverage of GT would be a useful method for alginate hydrogels to broaden their applications in the field of biomedicine. © 2022 Society of Industrial Chemistry.