Scaffold for tissue engineering fabricated by non-isothermal supercritical carbon dioxide foaming of a highly crystalline polyester

Porous scaffolds of a random co-polymer of ω-pentadecalactone (PDL) and ε-caprolactone (CL) (poly(PDL–CL)), synthesized by biocatalysis, were fabricated by supercritical carbon dioxide (scCO2) foaming. The co-polymer, containing 31mol.% CL units, is highly crystalline (Tm=82°C, ΔHm=105Jg−1) thanks to the ability of the two monomer units to co-crystallize. The co-polymer can be successfully foamed upon homogeneous absorption of scCO2 at T>Tm. The effect of soaking time, depressurization rate and cooling rate on scaffold porosity, pore size distribution and pore interconnectivity was investigated by micro X-ray computed tomography. Scaffolds with a porosity in the range 42–76% and an average pore size of 100–375μm were successfully obtained by adjusting the main foaming parameters. Process conditions in the range investigated did not affect the degree of crystallinity of poly(PDL–CL) scaffolds. A preliminary study of the mechanical properties of the scaffolds revealed that poly(PDL–CL) foams may find application in the regeneration of cartilage tissue.