Hierarchically porous 3D-printed ceramic scaffolds for bone tissue engineering
Shareen S. L. Chan, J. Roy Black, George V. Franks, Daniel E. Heath
Abstract
Sacrificial templating offers the ability to create interconnected pores within 3D printed filaments and to control pore morphology. Beta-tricalcium phosphate (TCP) bone tissue engineering (BTE) scaffolds were fabricated with multiscale porosity: (i) macropores from direct ink writing (DIW, a material extrusion 3D printing technique), (ii) micropores from oil templating, and (iii) smaller micropores pores from partial sintering. The hierarchically porous scaffolds possessed a total porosity of 58–70 %, comprising 54–63 % interconnected open pores. The in vitro results demonstrated that scaffolds with macroporosity promoted human osteoblast growth more than scaffolds with only microporosity. The elongated pores from the capillary suspension filament microstructure induced greater cell spreading than the sphere-like pores from the emulsion. Overall, the hierarchically porous scaffold with capillary suspension TCP filaments provided a superior microenvironment for significantly higher cell viability and proliferation than the other scaffolds, including a poly(ε-caprolactone) (PCL) control, a material currently used clinically as porous BTE scaffolds. The cellular response was further enhanced when macropore size was in the range of 570–590 μm. Therefore, the hierarchically porous scaffolds in this study are promising as BTE scaffolds, and the reported process of DIW of oil-templated colloidal pastes is a feasible strategy with potential for further customization. • Hierarchically porous ceramic scaffolds with macropores from 3D printing and micropores from oil-templating were fabricated. • Spherical micropores were formed from emulsions and elongated pores from capillary suspensions. • Elongated channels promote greater cell spreading than spherical pore morphology. • Macro- and elongated microporosity enhanced cell proliferation above PCL control. • Interconnected porosity enabled cell infiltration into filaments of some scaffolds.