Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA.
Acta Biomater. 2010 Jan;6(1):90-101. doi: 10.1016/j.actbio.2009.07.028. Epub 2009 Jul 23.
Biodegradable polymer-ceramic composite scaffolds have gained importance in recent years in the field of orthopedic biomaterials and tissue engineering scaffolds for improving the rate of degradation and limited mechanical properties of bioactive ceramics. This study sought to create composites using the electrospinning process to achieve fibrous scaffolds with uniform fiber morphologies and uniform ceramic dispersions. Composites consisting of 20% hydroxyapatite/80% beta-tricalcium phosphate (20/80 HA/TCP) and poly (epsilon-caprolactone) (PCL) were fabricated. The 20/80 HA/TCP composition was chosen as the ceramic component because of previous reports of greater bone tissue formation in comparison with HA or TCP alone. For electrospinning, PCL was dissolved in either methylene chloride (Composite-MC) or a combination of methylene chloride (80%) and dimethylformamide (20%) (Composite-MC + DMF). Composite-MC mats contained a bimodal distribution of fiber diameters with nanofibers between larger, micron-sized fibers with an average pore size of 79.6 + or - 67 microm, whereas Composite-MC + DMF fibers had uniform fiber diameters with an average pore size of 7.0 + or - 4.2 microm. Elemental mapping determined that the ceramic was distributed throughout the mat and inside the fiber for both composites. However, physical characterization using differential scanning calorimetry (DSC) and mechanical testing revealed that the ceramic in the mats produced with MC + DMF were more uniformly dispersed than the ceramic in the mats produced with MC alone. Maximum tensile stress and strain were significantly higher for Composite-MC + DMF mats compared with Composite-MC mats and were comparable with the mechanical properties of mats of PCL alone. For both composites, there was molecular interaction between the PCL and the ceramic, as demonstrated by a maximum increase of approximately 10 degrees C in the glass transition values with the addition of the ceramic, as confirmed by Fourier transform infrared analysis. In addition, the crystallization behavior of the composites suggested that the ceramic was acting as a nucleating agent. Cell viability studies using human mesenchymal stem cells (MSC) showed that both composite scaffolds supported cell growth. However, cell numbers at early time points in culture were significantly higher on mats produced from MC + DMF compared with mats prepared with MC alone. Further examination revealed that cells were able to infiltrate the pores of the Composite-MC mats, but remained on the outer surface of the Composite-MC + DMF and unfilled PCL mats during the culture period. The results of this study demonstrate that the solvent or solvent combination used in preparing the electrospun composite mats plays a critical role in determining its properties, which may, in turn, affect cell behavior.
可生物降解的聚合物-陶瓷复合材料支架在骨科生物材料和组织工程支架领域的重要性日益增加，可提高生物活性陶瓷的降解率和有限的机械性能。本研究旨在通过静电纺丝工艺制造复合材料，以获得具有均匀纤维形态和均匀陶瓷分散的纤维状支架。制备了由 20%羟基磷灰石/80%β-磷酸三钙（20/80HA/TCP）和聚己内酯（PCL）组成的复合材料。选择 20/80HA/TCP 作为陶瓷成分，因为先前的报告表明与单独的 HA 或 TCP 相比，它可以形成更多的骨组织。对于静电纺丝，将 PCL 溶解在二氯甲烷（复合材料-MC）或二氯甲烷（80%）和二甲基甲酰胺（20%）的混合物（复合材料-MC+DMF）中。复合材料-MC 垫包含纤维直径的双峰分布，具有较大的纳米纤维和微米级纤维之间的纳米纤维，平均孔径为 79.6+/-67μm，而复合材料-MC+DMF 纤维具有均匀的纤维直径，平均孔径为 7.0+/-4.2μm。元素映射确定陶瓷分布在整个垫子和纤维内部对于两种复合材料都是如此。然而，使用差示扫描量热法（DSC）和机械测试进行的物理特性分析表明，与单独使用 MC 制备的垫子相比，MC+DMF 制备的垫子中陶瓷的分散更均匀。与单独的 PCL 垫的机械性能相比，复合材料-MC+DMF 垫的最大拉伸应力和应变显着更高。对于两种复合材料，PCL 和陶瓷之间都存在分子相互作用，如通过添加陶瓷最大增加约 10°C 的玻璃化转变值所示，这通过傅里叶变换红外分析得到证实。此外，复合材料的结晶行为表明陶瓷充当成核剂。使用人骨髓间充质干细胞（MSC）进行细胞活力研究表明，两种复合支架均支持细胞生长。然而，在培养早期，在使用 MC+DMF 制备的垫子上细胞数量明显高于单独使用 MC 制备的垫子。进一步的检查表明，细胞能够渗透到复合材料-MC 垫的孔中，但在培养期间仍然留在复合材料-MC+DMF 和未填充的 PCL 垫的外表面上。这项研究的结果表明，用于制备静电纺丝复合垫的溶剂或溶剂组合在确定其性能方面起着关键作用，这反过来又可能影响细胞行为。
