3D-printed GEL/dbPTs composite scaffolds. Scaffolds display an increasing dbPTs content in figures A, B, and C from left to right. (A) Light microscopy images of the GEL, GEL/1% dbPTs, GEL/3% dbPTs and GEL/5% dbPTs scaffolds (from left to right) after freeze-drying. Scale bars: 1000 μm. (B) SEM images of the GEL/dbPTs scaffolds showing the surface morphology of the scaffolds on the top view and pore structure in the cross-sectional area of the scaffolds. Scale bars: 500 μm. (C) μCT images of the GEL/dbPTs scaffolds with increasing dbPTs content. Images display the dbPTs distribution in the scaffolds by (i) visual analysis of cross-sectional area and (ii) volume rendering images of GEL/1%dbPTs, GEL/3%dbPTs and GEL/5%dbPTs scaffolds. Scale bars: 1000 μm (i) and 500 μm (ii). (D) Polymer-particle interaction and dbPTs bond in the GEL/1%dbPTs scaffold. Asterisk, red arrows and white arrows indicate polymer, particles and the GEL/particle interaction, respectively. Scale bars: 50 μm (first), 20 μm (second), 10 μm (third and fourth).