Multistep deformation of helical fiber electrospun scaffold toward cardiac patches development.

The scaffolds used for cardiac patches must mimic the viscoelastic behavior of the native tissue, which expands up to high deformation levels of its sedentary size during the systole segment of pumping blood. In our study, we exposed fabricated electrospun samples to repeated multistep tension by applying and removing deformation to mimic the mechanical behavior of helical fibered cardiac scaffolds. Since the fiber-based specimens exhibit viscoelastic behavior, the transient responses to constant deformation caused stress relaxation and stress recovery. However, these transient viscoelastic operations performed at high strain enable unpredictable phenomena, usually hidden behind stress softening and folding (plasticity) phenomena; the material significantly reduces the required stress, and remaining deformation occurs. Thus, by regulating the fabrication (electrospinning parameters) process and preconditioning before setting, the actual viscoelastic behavior of the electrospun scaffolds will be evident, as well as their limitations towards their application to cardiac patches development.