Manipulating co-continuous polymer blends to create PCL scaffolds with fully interconnected and anisotropic pore architecture.

Purpose: Polymer blending is an attractive route to obtain new materials with superior properties. Control of their characteristics may be initially achieved by manipulating the phase morphology with different aspects (i.e, lamellar, dispersed or fibrillar) to form tailored architectures for different application fields. In particular, co-continuous microstructures due to the interpenetration of two different polymer phases in three dimensions are particularly interesting because they are able to offer a fully interconnected network with improvement of mechanical properties and fluid permeability for tissue engineering applications.

Materials and methods: Macro/microporous substrates with controlled architecture were obtained by blending hydrophylic and hydrophobic polymers, i.e, polycaprolactone (PCL) and poly(ethylene oxide)(PEO) respectively, in a co-continuous state by a twin-screw extruder.

Results: In accordance with the leaching-based approaches traditionally used in scaffold manufacturing, the removal of water soluble phases (i.e., PEO and sodium chloride (NaCl) crystals) enables a fully interconnected porous network to be formed, whereas post-extrusion stretching of the melt blend allows a desired elongation of polymer phases to be imparted before the polymer leaching, thus providing a controlled pore alignment.

Conclusion: the proposed investigation confirms that polymer blending is a promising approach to realize structurally organized platforms able to guide the regeneration processes of hierarchically organized tissues (i.e, tendons, muscles, ligaments and nerves).