Porous Scaffold Fabrication For Tissue Engineering Heart Valve And Design Of A Pulsatile Reactor In Animal

Tissue engineered heart valve is an inovative heart valve that constructed with live cells by applying the principle of life science and engineering. It overcomes the shortcomings of the mechanical valve and biological valve, has longevity, good biocompatibility and has no thrombosis and hymolysis issues.The principle and process of gelation of the PVA for tissue engineering heart valve were studied using thermodynamics and kinetics, and a theory of gelatin and processes of the PVA hydrogel was proposed using above-mentioned methods. With decreases of temperature, the aqueous PVA solution has a phase separation process and large PVA molecules aggregate into 3D network. However, because the PVA molecules are large and their interactions are relatively strong, their propagation rate is very small, thus the gelation process is limited by these factors. At room temperature, PVA would take over ten days or even longer time to gelate.Because of the difficulty of the gelation process at room temperature, a process of fast freezing and thawing was applied in alcohol. The PVA mixture was filled into a mold and then placed in the temperature controlled machine starting at a temperature of -20 C to prevent melting of the soldium chloride. The mixing of the PVA with soldium chloride particles would also promote the gelation process by form nucleations. Each freezing and thawing process enhanced the mechanical strength of the PVA hydrogel. After several cycles of this process, the PVA hydrogel was fully gelated and then was socked in water until the soldium chloride was fully disolved with water. The drying rate, tensile strength, strain at break and Young's modulus were obtained by testing the PVA samples. The biocompatibility of the materials was also studied using bone marrow mesenchymal stem cell (BMSCs) and promising results were obtained. The test results showed that the PVA material meet the requirement of tissue engineering a heart valve. An inovative concept of tissue engineering a heart valve in-vivo with dynamic strain on the scaffold was proposed and a in vivo device was designed to show the feasibility of the concept.