Macroporous photocrosslinked elastomer scaffolds containing microposity: preparation and in vitro degradation properties.

The engineering of soft tissue would benefit from the development of effective biodegradable scaffolds capable of dynamic, elastic loading. For this purpose, highly porous, elastomeric scaffolds containing microporous struts were prepared using a dual porogen approach and a photocrosslinkable elastomer. The combination of paraffin microbeads distributed through a water-in-[star-poly(lactide-co-epsilon-caprolactone) triacrylate dissolved in ethyl acetate] emulsion followed by photocrosslinking generated a macroporous foam scaffold of average porosities between 90% to 93%, with an average pore diameter of 104 +/- 31 microm with struts containing micropores of 3.1 +/- 2 microm average diameter. The mechanical properties of the scaffolds were readily manipulatable by altering the molecular weight of the star-poly(lactide-co-epsilon-caprolactone) triacrylate prepolymer used. The elastomer scaffolds degraded at the same rate as nonporous polymer samples of the same molecular weight, and exhibited similar changes in mass loss, mechanical properties, and sol fraction during in vitro degradation as found with the nonporous scaffolds. The modulus and stress at break of the scaffolds decreased continuously during degradation while the strain at break remained constant. These scaffolds show potential for use in the engineering of soft tissues.