Engineered Human Skin Fabricated Using Electrospun Collagen–PCL Blends: Morphogenesis and Mechanical Properties

TLDR

Engineered human skin is commonly fabricated using collagen scaffolds that often have poor mechanical properties. The study aims to improve the strength of collagen‑based skin scaffolds by blending poly(caprolactone) (PCL) with collagen. The blended scaffolds were fabricated into submicron fibers via electrospinning. Adding up to 10 % PCL evenly distributed within collagen improved scaffold strength and stiffness without compromising cell stratification, proliferation, or differentiation, whereas 30 % PCL caused phase separation, reduced cell viability, and weaker engineered skin, indicating that minimal PCL additions enhance scaffold mechanical properties but higher concentrations do not translate into stronger engineered skin due to impaired epidermal development.

Abstract

Engineered human skin is commonly fabricated using collagen scaffolds that often have poor mechanical properties. To improve the strength of collagen-based scaffolds, poly(caprolactone) (PCL) was blended with collagen and formed into submicron fibers using electrospinning. At concentrations < 10% PCL (M(PCL)/[M(Collagen) + M(PCL)] x 100), the PCL component was evenly distributed within the collagen matrix. Increasing the PCL component to 30% caused separation of the collagen and PCL phases forming local domains of PCL within the collagen matrix. Tensile testing indicated that 10-100% PCL concentrations significantly improved the strength and stiffness of the acellular scaffolds. Engineered skin (ES) made with blended collagen-PCL at a concentration of up to 10% PCL did not significantly alter the stratification of the cells, cell proliferation, or epidermal differentiation compared to the 100% collagen group. Ultimate tensile strength of ES fabricated with the collagen-PCL blends was not significantly greater than that of ES made with 100% collagen scaffolds (0% PCL). The 30% PCL group had the least amount of mechanical strength likely caused by poor epidermal formation and reduced cell viability. These results indicate that minimal additions of PCL can be blended with collagen to produce scaffolds suitable for tissue engineering of human skin. However, the increase in scaffold strength with higher PCL concentrations did not result in significantly stronger ES, indicating that high cell viability and proper development of the epidermis are important factors for developing ES with high strength.