3D-printed biodegradable composite scaffolds with significantly enhanced mechanical properties via the combination of binder jetting and capillary rise infiltration process

Abstract For hard tissue engineering applications, biodegradable composite scaffolds have been extensively investigated because of their satisfactory mechanical properties and biocompatibility. Recently, 3D printing processes have received substantial attention in the tissue engineering field because of their ability to be customized for tissues that have suffered different types of loss or damage for each patient. However, previous studies on material extrusion-based techniques lack flexibility in the filler loading amount and cannot fulfill requirements that aim to enhance mechanical properties and biocompatibility. Herein, we propose a biodegradable polymer-based composite scaffolds with high ceramic loadings fabricated using the binder jetting (BJ) technique conjugated with capillary rise infiltration. A calcium sulfate hemihydrate (CSH) scaffold was fabricated using BJ-based 3D printing. Thereafter, CSH was transformed into biphasic calcium phosphate (BCP) using hydrothermal treatment, followed by heat treatment. Melted polycaprolactone (PCL) was infiltrated in the resulting BCP scaffold. BCP was then completely dispersed in the PCL matrix, and the calculated PCL loading in the BCP matrix exceeded 40 vol%. The PCL/BCP composite scaffold demonstrated the highest compressive strength, moduli, and toughness with the fracture mode shifted from brittle to less brittle. Moreover, a stable PCL/BCP surface promotes initial cell responses and shows sufficient proliferation and differentiation of pre-osteoblast cells.