Fabrication of Porous Poly(ε-caprolactone) Scaffolds Containing Chitosan Nanofibers by Combining Extrusion Foaming, Leaching, and Freeze-Drying Methods

Abstract

Biomimetic porous poly(ε-caprolactone) (PCL) scaffolds containing chitosan nanofibers (CSNF) were produced by using a hybrid process that combines extrusion foaming, water-soluble phase leaching, and freeze-drying. The high porosity and interconnectivity of the scaffolds were achieved by supercritical fluid foaming and the addition of water-soluble poly(ethylene oxide) (PEO) and sodium chloride (NaCl) as porogens. The porosity of the scaffolds after leaching was over 78%. The structure of the chitosan nanofibers introduced into the micropores of the scaffolds was similar to the collagen bundles in the extracellular matrix (ECM). The chitosan nanofibers enhanced the compressive modulus of the scaffolds slightly and improved the water uptake ability by as much as 35% compared to the scaffolds without chitosan. A 3T3 fibroblast cell culture was performed to investigate the biocompatibility of the scaffolds, which revealed that the cells proliferated better on the PCL/chitosan scaffolds than on the PCL scaffolds. Regarding cell morphology, cells on the PCL scaffolds were rounded in the form of tumoroids, suggesting poor cell adhesion and poor cell–scaffold interactions. In contrast, cells on the PCL/chitosan scaffolds were elongated and spindle-shaped, indicating favorable cell–scaffold interactions. Therefore, the highly porous PCL scaffolds containing chitosan nanofibers fabricated in this study have the potential to be used in tissue engineering applications.