Engineering and monitoring 3d cell constructs with time‐evolving viscoelasticity for the study of liver fibrosis in vitro

Liver fibrosis is generally associated with an over‐production and crosslinking of extracellular matrix proteins, causing a progressive increase in both the elastic and viscous properties of the hepatic tissue. We describe a strategy for mimicking and monitoring the mechano-dynamics of the 3D microenvironment associated with liver fibrosis. Cell‐laden gelatin hydrogels were crosslinked with microbial transglutaminase using a purpose‐designed cytocompatible two-step protocol, which allows for the exposure of cells to a mechanically changing environment during culturing. A bioreactor was re‐engineered to monitor the mechanical properties of cell constructs over time. The results showed a shift towards a more elastic (i.e., solid‐like) behaviour, which is likely related to an increase in cell stress. The method effectively mimics the time‐evolving mechanical microenvironment associated with liver fibrosis and could provide novel insights into pathophysiological processes in which both elastic and viscous properties of tissues change over time.