National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou, China; Department of Mechanical Engineering, University of Wisconsin-Madison, WI, USA.
Mater Sci Eng C Mater Biol Appl. 2013 Dec 1;33(8):4767-76. doi: 10.1016/j.msec.2013.07.037. Epub 2013 Aug 2.
Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications.
聚乳酸（PLA）和热塑性聚氨酯（TPU）是两种生物相容性和可生物降解的聚合物，可用于生物医学应用。PLA 具有刚性机械性能，而 TPU 具有柔性机械性能。通过双螺杆挤出和微发泡注塑技术，首次制备了不同比例的混合 TPU/PLA 组织工程支架，以实现可调性能。使用多种测试方法对这些材料进行了表征。傅立叶变换红外光谱（FTIR）证实了混合物中两种成分的存在；差示扫描量热法（DSC）和动态力学分析（DMA）证实了 TPU 和 PLA 之间的不混溶性。扫描电子显微镜（SEM）图像证实，在所研究的组成比下，PLA 分散在 TPU 基体中呈球或岛状，这种相形态进一步影响了支架的微观结构和表面粗糙度。该共混物具有广泛的机械性能，涵盖了几种人体组织的要求。3T3 成纤维细胞培养表明，支架能够很好地支持细胞增殖和迁移。最重要的是，这项研究证明了大规模生产具有可调微观结构、表面粗糙度和机械性能的生物相容性 PLA/TPU 支架的可行性，这些支架有可能作为多种组织工程应用中的人工支架。
