Control of wall thickness of blood vessel biomodel made of poly (vinyl alcohol) hydrogel by a three-dimensional-rotating spin dip-coating method

To control the thickness of a PVA-H biomodel of human arteries and veins (150 to 800 μm in thickness), a threedimensional-rotating spin dip-coating apparatus was fabricated. A straight aluminum cylinder (Ra = 0.16 μm) was employed as substrate. Spin dip-coating was carried out in a cooling chamber at 10°C for 1 hour, and then the substrate was quenched at -30°C for gelation of PVA. The thickness of the deposited PVA-H was measured by using a confocal laser displacement meter. Under the experimental conditions employed, PVA-H with a thickness over 30 μm was obtained. The thickness linearly increased with repeated dippings. The thickness of PVA-H depends on the dipping withdrawal speed, the viscosity of the PVA solution, and the diameter of the substrate. Furthermore, the thickness of PVA-H was found to be almost the same when the viscosity of the PVA solution was constant, regardless of the concentrations of PVA. These results indicate that a tubeshaped PVA-H biomodel with desired thickness and physical properties can be obtained by using a spin dip-coating technique and that PVA-H can mimic the wall thickness of various arteries and veins.