Development of a stereo dip-coating system for fabrication of tube-shaped blood vessel models

Figures

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  Figure 1. Geometries of the substrate. (A) ideal geometry and measuring points of wall thickness for 1-directional dip-coating, (B) ideal geometry for stereo dip-coating, (C) the relationship between angles at measuring points from two views and length from the top in the centerline. Left panel shows the frontal view (view A*) and right panel shows the lateral view (view B*). The drawings are not to scale (unit: mm).

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  Figure 2. Angular control dip-coating (ACDC) system. (A) Outline image of the system, right panel, (B) Working process of the program, (C) Mechanism of the detection at the edges of substrate. The edge is detected from the binarization of the image.

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  Figure 3. Influence of the substrate angle on the wall thickness. This figure is edited from ref. 27.

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  Figure 4. Measurement process of wall thickness in the PVA-H model. (A) Substrate geometry from micro CT image, (B) centerline from the substrate geometry, (C)PVA-H geometry from micro CT image, (D) getting the segment using the PVA-H geometry (C) and vertical cutting planes of the centerline (B), (E) Measuring points of the cutting planes in the substrate for stereo dip-coating in Fig. 1 (B) (O; original point, E; end point, I; inflection point), (F) wall thickness measurement on the segment of the cutting planes to evaluate the uniformity. A* and B* indicate the front and lateral view points in each curve and the numbers indicate the angle in the curves.

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  Figure 5. Micro CT images and thickness of the PVA-H tube-shaped models deposited on the curvature substrate. Each experiment was performed thrice (n = 3). (A) micro CT images of no ACDC, (B) micro CT images with 1-directional angular control, (C) averaged thickness of no ACDC (mean + SD), (D) averaged thickness of 1-directional ACDC and no ACDC (mean + SD), (E) boxplots of averaged wall thickness in whole section (mean ± SD). In (A,B), the left panel shows images of the vertical-sectional view and the right panel shows images of the cross-sectional view. The thickness was measured every 90° (in, out, left, and right) in each cross section.

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  Figure 6. Substrate angle from the vertical line during pull-up to evaluate the ACDC behavior. The angle range on the vertical axes should be different based on the stability of the motors. ((A) with ACDC, (B) no ACDC, F; frontal view of the substrates, L; lateral view of the substrates).

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  Figure 7. Example of cutting plane images in the substrates to measure the wall thickness on the cutting planes and to evaluate uniformity of wall thickness. (A) ACDC substrate, (B) no ACDC substrate, (C) Color contours of ACDC model for the relationship between wall thickness and centerline, (D) Color contours of no ACDC model for the relationship between wall thickness and centerline. The scales in (A,B) are 1 mm square each.

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  Figure 8. Distribution of wall thickness in each cutting plane. Each experiment was performed thrice (n = 3) and the averages of the results were plotted. (A) mean wall thickness, (B) maximum wall thickness, (C) standard deviation of the wall thickness. (D) boxplots of averaged wall thickness in whole section.