Fabrication and Modeling of an Electrospun Tri-Polymer Composite for the Engineering of Fibrous Tissues

Aligned, electrospun scaffolds are a useful tool for the engineering of fiber-reinforced tissues (such as tendon, meniscus, and muscle) as they mimic the topography and anisotropy of the native tissue extracellular matrix (ECM) [1]. We have shown that fiber-alignment of slow-degrading poly(ε-caprolactone) (PCL) enhances the organization of newly-formed ECM and improves construct properties [2]. However, one significant drawback to these 3D templates is their small pore size, resulting from tight fiber packing, which hampers cell infiltration. To increase scaffold porosity and thereby accelerate cell ingress, we have recently reported on the fabrication of dual polymer composite scaffolds containing both water-soluble poly(ethylene oxide) (PEO) and PCL fibers [3]. Removal of the sacrificial PEO fibers before seeding improved cell infiltration, but did so at the cost of the overall structural integrity. To further expand the potential properties (mechanics and degradation) of these composite scaffolds, this study introduced a third component (50:50 poly(lactic-co-glycolic acid) (PLGA)) using a newly constructed tri-polymer electrospinning device. We evaluated each polymer singly and when combined into a tri-polymer (3P) fibrous network. To better understand the mechanical response of these composites, we used a hyperelastic, constrained mixture model to assess and predict the response of these composite nanofibrous meshes for a range of compositions.