Bio-Inspired Fiber Reinforcement for Aortic Valves: Scaffold Production Process and Characterization

Figures

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  Figure 1. Design of the fiber-reinforced scaffold and mandrel of the commissure side is towards the top of the images: (A) Geometrical alignment of anchor points on the mandrel; (B) mandrel with one layer of polycarbonate polyurethane (PCU) and polyvinylidene fluoride (PVDF)-reinforcement fibers; (C) finished fiber-reinforced scaffold; (D) scanning electron microscopy (SEM) image e-spun PCU with fabrication settings (10 wt%, 26 kV and 10 cm distance between needle and mandrel); (E) section of the fiber-reinforced scaffold at the end of the production process.

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  Figure 2. Biaxial test of the polycarbonate polyurethane (PCU) and fiber-reinforced scaffold: (A) schematic test procedure of the biaxial test; (B) leaflet cut from the tubular fiber-reinforced scaffold to be tested; (C) simulated mechanical stress in closed position; (D) fiber-reinforced scaffold cut open in radial direction, all three leaflets are visible; (E) failed non-reinforced PCU sample after destructive test; (F) failed fiber-reinforced scaffold leaflet after destructive test. The direction shown in A applies to all other images as well.

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  Figure 3. (A) Mechanical test results of the native leaflet in circumferential direction; (B) mechanical test results of the non-reinforced polycarbonate polyurethane (PCU) in circumferential direction; (C) mechanical test results of the scaffold in circumferential direction; (D) mechanical test results of the native leaflet in radial direction; (E) mechanical test results of the non-reinforced PCU in radial direction; (F) mechanical test results of the scaffold in radial direction; x-axis strain [%] y-axis membrane tension [N/m].

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  Figure 4. (A) Membrane Tension of the native heart valve, non-reinforced polycarbonate polyurethane (PCU) and fiber-reinforced scaffold at physiological strains (10% in circumferential direction and 30% in radial direction) at the end of the cyclic tests; (B) Membrane Tension of the native heart valve, non-reinforced PCU and fiber-reinforced scaffold at the point of destruction. (C) Young modulus of the native heart valve, non-reinforced polycarbonate polyurethane (PCU) and fiber-reinforced scaffold at physiological strains (10% in circumferential direction and 30% in radial direction) at the end of the cyclic tests; (D) Young modulus of the native heart valve, non-reinforced PCU and fiber-reinforced scaffold at the point of destruction. * marks a significant difference compared to the native heart valve (9 samples each were tested).

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  Figure 5. Hemodynamic characterization of a fashioned valve: (A–E) typical opening and closing cycle of the heart valve under aortic conditions with simulated mechanical stress; (F) aortic and ventricular pressure over two cycles at 70 BPM; (G) fashioned valve in silicon aorta.