Mechanical Strengthening and Degradation Regulation of Iron Foam-Polycaprolactone Interpenetrating Composite Scaffolds

Abstract

Porous materials, owing to their unique pore networks, are expected to positively influence the enhancement of mechanical properties and modulation of degradation behavior. Herein, composite scaffolds were fabricated by a combination of triply periodic minimal surfaces (TPMS) design, selective laser sintering (SLS), and hot-pressing technology, in which iron foam (FFe) and polycaprolactone (PCL) were the reinforcing phase and matrix, respectively. Mechanical strengthening was achieved by forming an interpenetrating structure between the continuously porous FFe and TPMS structure PCL. Regarding degradation regulation, a catalytic degradation microcirculation system (CDMS) was constructed through acid-base neutralization reactions between FFe and PCL degradation products. The results indicated that the compressive and tensile moduli of composite scaffolds were increased by an astonishing 1758.8% and 466.0% compared with the PCL scaffold, which is attributed to the synergistic load sharing and stress transmission efficiency of the interpenetrating structures. In addition, the weight loss of the composite scaffold was 3.6 times higher than that of the PCL scaffold, indicating that the constructed CDMS is expected to achieve degradation regulation. Encouragingly, the composite scaffold also exhibited a good apatite induction ability during in vitro culture. Therefore, the constructed composite scaffold realizes the regulation of mechanical and degradation properties, so that it has potential applications in bone tissue engineering.

Keywords: TPMS design; combined technology; degradation regulation; interpenetrating structure; mechanical strengthening.