Shear and Compressive Stiffening of Dual-Cross-Linked Alginate Hydrogels with Tunable Viscoelasticity
Kexin Zhang, Zecheng Li, Yu‐Chang Chen, Il‐Chul Yoon, Adam Graham, Kyle H. Vining
Abstract
Alginate biopolymers were modified with norbornene (Nb) and tetrazine (Tz) functional groups to generate hydrogel networks with tunable ionic and covalent cross-linking for modeling the strain-stiffening behavior of extracellular matrix. The mechanical properties of the hydrogels were investigated by oscillatory shear rheology, axial compression, and stress relaxation analysis. Introducing Nb-Tz irreversible covalent cross-links yielded dual-cross-linked hydrogels with stiffer and more elastic properties compared to purely ionically cross-linked alginate networks. The strain stiffening effect was observed under both shear amplitude sweeps and stepwise axial compression tests for the dual-cross-linked hydrogels. This study provides valuable insights into the structure-property relationship of dual-cross-linked biopolymer hydrogels for designing tunable extracellular matrix mimics of fibrotic tissues.