Gelatin methacrylate-alginate hydrogel with tunable viscoelastic properties

Although native extracellular matrix (ECM) is viscoelastic, synthetic biomaterials used in biomedical engineering to mimic ECM typically exhibit a purely elastic response when an external strain is applied. In an effort to truly understand how living cells interact with surrounding ECM matrix, new biomaterials with tunable viscoelastic properties continue to be developed. Here we report the synthesis and mechanical characterization of a gelatin methacrylate-alginate (Gel-Alg) composite hydrogel. Results obtained from creep and compressive tests reveal that the alginate component of Gel-Alg composite, can be effectively crosslinked, un-crosslinked and re-crosslinked by adding or chelating Ca²⁺ ions. This work demonstrates that Gel-Alg is capable of tuning its viscoelastic strain and elastic recovery properties, and can be potentially used to design ECMmimicking hydrogels.