| Summary: | 碩士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 102 === Heart failure is a major cardiovascular disease with high mortality. Via the application of cardiac tissue engineering, damaged myocardium can be replaced by cardiac scaffold. The cardiac scaffold can not only enhance cardiac function but also improve cardiac remodeling. In cardiac tissue engineering, scaffolds must be porous, resilient, biodegradable, biocompatible and similar mechanical properties matching with native tissue. Electrospin is a promising technique to fabricate nanofibrous scaffold which is mimic the structure of extracellular matrix (ECM) and provides high surface area with interconnecting pores. Polyurethane urea have been considered good candidates with its elasticity and toughness for utilizing in cardiac tissue engineering. Ethyl cellulose(EC) as a kind of chemically modified cellulose exhibits excellent plasticity, good solubility in organic solvents, biocompatibility and high mechanical intensity. Therefore, combination of polyurethane urea and ethyl cellulose as a composite biomaterial possesses promising potential in realistic application of cardiac tissue engineering.
In this study, we have synthesized biodegradable polyurethane urea from polycaprolactone diols (PCL), isophorone diisocyanate (IPDI) and 1,4-diaminobutane (DAB) by reacting PCL diols with IPDI first then with DAB. Polyurethane urea were further fabricated into fibrous scaffolds by electrospinning using dimethylacetamide (DMAc) as a solvent. We investigated the effect on H9C2 cells growth by changing fiber width, the blending ratio of ethyl cellulose and alignment of fibrous scaffold. The chemical structure of synthesized polyurethane urea was confirmed by IR and its molecular weight was determined by GPC. The molecular weight of polyurethane urea and ethyl cellulose were 68kDa and 61kDa respectively. Their thermal, mechanical, and viscoelastic properties were also investigated to exhibit high elasticity and strength.
The scaffold with wider fibers have higher tensile strength and degradation rate. More increasing cell amount rate was discovered on the scaffold with width fibers. We also blended polyurethane urea with ethyl cellulose which enhance its mechanical properties and biocompatibility. In three different blending ratio(5:5, 7:3 and 9:1), H9C2 cells exhibit better morphology and growing rate on the scaffold with 9:1 blending. In addition, we fabricated scaffold with aligned fibers by employing a rolling collector. Aligned scaffold show higher Young’s modulus and tensile strength as compared to isotropic one. The H9C2 cells cultured on aligned fibers showed more pronounced elongation and better alignment compared to those cultured on random fibers. In summary, aligned electrospun biodegradable polyurethane urea/EC scaffold has potential for the repair of damaged heart tissue.
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