3D printing of Pickering emulsion inks to construct poly(D,L-lactide-co-trimethylene carbonate)-based porous bioactive scaffolds with shape memory effect

Abstract

Biocompatible and bioactive scaffolds with multiscale porosity, shape memory effect and drug delivery performance are highly promising in bone tissue engineering applications within the approach of minimally invasive surgical implantation. In this study, we report an effective method to fabricate multiscale porous bioactive (MPB) scaffolds with shape memory effect by freeze drying of 3D printed high internal phase Pickering emulsion (Pickering HIPE) templates stabilized by hydrophobically modified hydroxyapatite and silica nanoparticles. MPB scaffolds containing a shape memory polymer matrix of poly(D,L-lactide-co-trimethylene carbonate) display high porosity and fully interconnected filament networks with multiscale pore structures. The in vitro biomineralization study verifies that MPB scaffolds are bioactive with the apatite formation ability. The thermal property testing shows that the glass transition temperature of MPB scaffolds is easily tuned to fall between 45.9 and 49.1 °C by varying the HIPE composition. Moreover, MPB scaffolds exhibit observable shape memory properties with fast shape recovery. The antibacterial drug enrofloxacin can be efficiently loaded into MPB scaffolds and then released in a sustained manner displaying effective antimicrobial effect. Furthermore, cell culture assays confirm that MPB scaffolds could sustain the cell growth, proliferation and osteogenic differentiation, indicating the cytocompatibility and osteoinduction activity of MPB scaffolds. Therefore, combining freeze drying with 3D printing of Pickering HIPE templates paves the way towards MPB scaffolds with shape memory effect, which are promising as minimally invasive implantation scaffolds in bone tissue engineering applications.