Constitutive Effects of Hydrolytic Degradation in Electro-Spun Polyester-Urethane Scaffolds for Soft Tissue Regeneration

In tissue regenerative implants, porosity allowing the ingrowth of cells and tissue is a key factor for the long-term success. While vital for healing and tissue regeneration, the use of highly porous structures may adversely affect the mechanical properties of the scaffold, in particular when viscoelastic polymeric materials are used. In the case of biodegradable scaffold materials, the effect of the degradation process on mechanical and structural properties of the scaffold is yet another aspect to be considered. Both tissue ingrowth and biodegradation are concurrent transient processes which change the mechanical and structural properties of the implanted device over time. Ingrowth of cells and tissue typically results in an increase in structural stiffness whereas scaffold degradation leads to loss of mechanical properties and potentially to structural disintegration. The aim of the research presented in this chapter was the investigation of the change of mechanical properties of a biodegradable, electro-spun polyester-urethane scaffold for soft tissue regeneration during hydrolytic degradation and the development of a constitutive model that is suitable for capturing these changes.