Viscoelastic modeling of the stress relaxation behavior for the bionic extracellular matrix polymer scaffold

Viscoelasticity of the extracellular matrix (ECM) plays a critical part in controlling cell behavior. However, the structure-related viscoelasticity of the synthetic ECM and its mechanism are rarely reported. Due to its high tissue similarity, synthetic ECM with structural anisotropy and viscoelasticity holds a great promise for structure and function correlation studies. Here, we reported a series of synthetic composite hydrogel-based ECM with different levels of anisotropic orientation and viscoelastic properties through recently developed post-treatment procedures (the confined pre-strain stretching and drying procedure, the soaking salt solution procedure, and the synergetic sequences of two procedures). Further, by establishing a multimode Maxwell viscoelastic mechanic model, the stress relaxation behavior of the bionic ECM with different levels of anisotropic orientation and viscoelastic properties was simulated successfully. The characteristic viscoelastic parameters of the bionic ECM could also be calculated exactly. This study presented a novel viscoelastic mechanic model for mimicking the key ECM features of the synthetic ECM with anisotropic structure and viscoelasticity properties.