Numerical model of hydrogel mechanics, fluid flow, and enzyme diffusion and degradation

Cartilage tissue engineering relies on the use of scaffolds to provide a temporary three dimensional environment for cells to grow into functional tissue that can be used to replace damaged tissue within the body. To effectively assist in the production of functional tissue, the scaffold needs to provide mechanical strength to the cells but still allow for extracellular matrix production through degradation. There are two main types of degradation methods: hydrolytic and enzymatic. The dynamics and kinetics of hydrolytically degradable scaffolds are fairly simple because they degrade in a bulk manner whereas the dynamics and kinetics of enzymatically degradable scaffolds is much more complicated due to the heterogeneous nature of localized degradation.;The present work develops a numerical model to be able to both analyze the dynamics of cell mediated enzymatic degradation of hydrogels, and guide development of new enzymatically degradable hydrogels. This model is a nonlinear, triphasic poromechancal model which solves for the solid hydogel matrix displacement, fluid pore pressure, enzyme concentration and cross-linking density using the finite element method. This model is able to incorporate the changes to the mechanical, permeation, and diffusive properties that occur during enzymatic degradation through the use of rubber elasticity and equilibrium swelling theories.;This model is qualitatively validated by evaluating the model using an example polymer and examining how changes in parameters effect the diffusive and degradation characteristics of the hydrogel. In addition to this validation, a sensitivity analysis was performed.