Porous Poly(ε-caprolactone)–Poly(<scp>l</scp>-lactic acid) Semi-Interpenetrating Networks as Superior, Defect-Specific Scaffolds with Potential for Cranial Bone Defect Repair

The treatment of irregular cranial bone defects is currently limited due to the graft resorption that can occur when an ill-fitting interface exists between an autograft and the surrounding tissue. A tissue engineering scaffold able to achieve defect-specific geometries could improve healing. This work reports a macroporous, shape memory polymer (SMP) scaffold composed of a semi-interpenetrating network (semi-IPN) of thermoplastic poly(l-lactic acid) (PLLA) within cross-linked poly(ε-caprolactone) diacrylate (PCL-DA) that is capable of conformal fit within a defect. The macroporous scaffolds were fabricated using a fused salt template and were also found to have superior, highly controlled properties needed for regeneration. Specifically, the scaffolds displayed interconnected pores, improved rigidity, and controlled, accelerated degradation. Although slow degradation rates of scaffolds can limit healing, the unique degradation behavior observed could prove promising. Thus, the described SMP semi-IPN scaffolds overcome two of the largest limitations in bone tissue engineering: defect "fit" and tailored degradation.