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 31 mol.% CL units, is highly crystalline (Tm = 82 °C, ΔHm = 105 J g−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 100-375 μm 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.