Co-continuous calcium phosphate/polycaprolactone composite bone scaffolds fabricated by digital light processing and polymer melt suction

Abstract

Innovative scaffolds consisting of a cartesian mesh of interpenetrated composite struts of polycaprolactone (PCL) and β-tricalcium phosphate (β-TCP) in a core/shell configuration are developed. Photocurable slurries with high solid-loading (40 vol% TCP) and reduced viscosity were produced by adding camphor and used to fabricate ceramic preforms with hollow struts through Digital Light Processing (DLP). After sintering the structures were suction-infiltrated by molten PCL, resulting in co-continuous composite scaffolds. Their mechanical performance was evaluated in compressive and bending tests and analyzed under the light of stress fields calculated by finite element numerical simulations. Toughness of the scaffolds was notably increased after incorporating the polymeric core. The new co-continuous architecture facilitates impregnation and improves the isotropy of the reinforcement provided by the polymeric core over other reported alternatives but increases the stresses in the ceramic. This was compensated, however, by the increased intrinsic strength associated to using a more concentrated feedstock.