Fig. 3 | npj Regenerative Medicine

Fig. 3

From: Biomimetic heterogenous elastic tissue development

Fig. 3

Structural, mechanical biomimicry of heterogenous tissue; trachea as an exemplar. a Structural biomimicry of an adult trachea: (i) Trachea is relatively static, longitudinally flexible but radially rigid with intermittent cartilage ‘c’ shaped rings, which maintains luminal structure, with a softer trachealis muscle in the posterior providing the compliance for optimal ventilation.13, 18, 19, 24,25,26 (ii) 3D CAD model of trachea generated using Blender software. (iii) STL of the CAD (ii) was sliced in slic3r (SI) and 3D printed with a dual extrusion FDM printer with TPU 90 to mimic cartilaginous rings and TPU 80 for softer trachaelis muscle and connective tissue. (iv) 3D printed TPU biomimetic tracheal structure. (v) Ultrastructure of the 3D printed biomimetic tracheal construct; SEM images of respective cross sectional and surface images. a luminal surface post processed with L-AME and collagen b cross sectional view illustrating the structure to potentially facilitate blood vessel infiltration. b (i) SimplewareTM software modelling of generic CAD of a trachea to match a patient trachea (CT scan) as a potential stent. c Mechanical and functional biomimicry. (i) Tracheal segements (n = 12) demonstrated greater strength radially (p < 0.01) and greater longitudinal elongation (p < 0.05) resulting in significantly lower, elastic modulus (p < 0.05) for longitudinal segments (n = 12) compared to circumferential segments (n = 10) with no significant difference of elastic modulus between anterior and posterior longitudinal segments (p > 0.05) but significantly higher elastic modulus for anterior circumferential segments compared to that of posterial circumferential segments. (ii) Greater force (p = 0.05) was required to compress tracheal segments (25/23) (n = 8) with anterior compression than required to compress laterally. (iii) Flexibility in bending; the constructs were bent in the anterior plane with ease without causing luminal closure and returned to their original shape upon removal of the force. Constructs (n = 5) were laterally bent with even greater ease (p = 0.05). (iv) Compliance under a range of pressures monitored with ultrasoundscans, with the probe placed a across and b along the 3D printed tracheal construct. Double headed arrows on scans indicate maximum distension at a given pressure

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