Embedded direct ink writing of 4D printed tracheal scaffold for airway tissue engineering

Purpose This study aims to fabricate a polylactic acid (PLA)/polypropylene carbonate (PPC) composite tracheal scaffold using embedded 3D printing and demonstrate its triple-shape memory functionality. Design/methodology/approach Three tracheal scaffolds of different geometry (cylinder, bellow and spiral-shaped) were investigated using mechanical (radial and longitudinal compression tests) and compared with that of the native goat trachea. As a case study, the bellow-shaped scaffold was implanted inside the lumen of the native goat trachea and the triple-shape memory behavior was demonstrated. To further assess the biocompatibility of the samples, MTT, live/dead and cell adhesion assays were conducted using fibroblast cells. Findings The thermal characterization revealed that the effect of Laponite nano-silicate on the PLA/PPC composite surface had negligible effect on the thermal transitions and shape-memory ratios. Comparative studies between the three scaffolds highlighted that the bellow-shaped scaffold was found to closely mimic the mechanical properties (radial and longitudinal compression) of the native goat trachea. The PLA/PPC composite samples fabricated using embedded 3D printing were found to have a shape-fixity ratio of 96.07 ± 3.06% and a shape-recovery ratio of 95.88 ± 2.61%. The in vitro cytotoxicity of the PLA/PPC composite demonstrated excellent biocompatibility. Originality/value The proposed methodology of embedded 3D printing allows for fabrication of complex geometry structures using a wide variety of polymers by leveraging the solvent–water interaction capability.