Fig. 1 | npj Regenerative Medicine

Fig. 1

From: Biomimetic heterogenous elastic tissue development

Fig. 1

Architectural and mechanical biomimetic design flexibility with direct 3D printed thermoplastic polyurethane. a (i). 3D hollow tubular CAD (20 mm height × 15 mm diameter) was sliced (Slic3r) to have a range of infill densities in two different infill patterns (hexagonal and linear). Corresponding 3D printed structures were obtained with TPU90 with clear morphological definition. (n = 6) (ii). A range of 3D printed tubular structures were obtained by varying the basic code (indicated in supplementary methods) for (the wall thickness, infill density and diameter) of the tubular hollow CAD structure for a (i). b (i). The ‘pore’ size is significantly greater in the hexagonal constructs than linear. The increase in infill density decreased ‘pore’ size, but an exception observed between 60 to 80% in the hexagonal infill (P > 0.05). (ii). Compression strength of 3D printed structures corresponding to morphological details described in a (i). The hexagonal infill was significantly more compliant than the linear infill at 40, 60, 80% (P < 0.001) but not 20% (P > 0.05). Overall the linear infill requires significantly more force to compress (P < 0.05). c (i) The surface architecture of 3D printed TPU90 scaffolds (15 × 15 × 1.5 mm) with significantly different fibre thickness in opposite directions. (ii) Biaxial test demonstrating a density dependant increase in elastic modulus of scaffolds, as well as material anisotropy with significantly higher compressive stress in y-axis, and greater elongation in x-axis. (p < 0.05). (iii) The pore size of the scaffolds is inversely related to the infill density (p < 0.05). d (i) a SEM of a 3D printed TPU90 as a ligament structure that mimics collagen fibre morphology b with an infill gradient (indicated with double headed arrows) to modulate varying tissue interphases. (ii) SEM of Porolay (PVA + TPU) biomimicking fibrous morphology as potential substitutes for connective tissue

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