Ultrasonic Laboratory, National Institute of Standards, Giza, Egypt.
Department of Physics, Faculty of Science, Suez University, Suez, Egypt.
Int J Pharm. 2020 Jul 30;585:119502. doi: 10.1016/j.ijpharm.2020.119502. Epub 2020 Jun 4.
Composite structures are at the frontier of materials science and engineering and polymeric/ceramic composites present one of their most prospective subsets. Prior studies have shown both improvements and deteriorations of properties of polymers upon the addition of ceramic phases to them, but not many studies have dealt with the direct comparison of chemically distinct inorganic additives. The goal of this study was to compare the properties of ε-polycaprolactone (PCL) thin films supplemented with alumina, graphene, carbonated hydroxyapatite or titania particles, individually, in identical amounts (12 wt%). The composite films were analyzed for their phase composition, grain size, morphology, surface roughness, porosity, cell response, mechanical properties and electrochemical performance. Each additive imparted one or more physical or biological properties onto PCL better than others. Thus, alumina increased the microhardness of the films better than any other additive, with the resulting values exceeding 10 MPa. It also led to the formation of a composite with the least porosity and the greatest stability to degradation in simulated body fluid based on open circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS). Titania made the surface of PCL roughest, which in combination with its high porosity explained why it was the most conducive to the growth of human fibroblasts, alongside being most prone to degradation in wet, corrosive environments and having the highest Poisson's ratio. Graphene, in contrast, made the surface of PCL smoothest and the bulk structure most porous, but also most conductive, with the OCP of -37 mV. The OCP of PCL supplemented with carbonated hydroxyapatite had the highest OCP of -134 mV and also the highest mechanical moduli, including the longitudinal (781 MPa), the shear (106 MPa), the bulk (639 MPa), and the elastic (300 MPa). The only benefit of the deposition of multilayered PCL films supplemented with all four inorganic additives was to enable a relatively high resistance to degradation. This study demonstrates that the properties of thin PCL films could be effectively optimized through the simple choice of appropriate inorganic additives dispersed in them. There is no single additive that proves ideal for improving all the properties of interest in PCL thin films, but their choice should be adjusted to the actual application. One such method of compositional optimization could prove crucial in the effort to develop biocomposites for superior performance in tissue engineering applications.
复合材料处于材料科学与工程的前沿，而聚合物/陶瓷复合材料则是最有前途的子集之一。先前的研究表明，向聚合物中添加陶瓷相可以改善或恶化聚合物的性能，但很少有研究涉及对化学性质不同的无机添加剂进行直接比较。本研究的目的是比较单独添加氧化铝、石墨烯、碳酸羟基磷灰石或二氧化钛颗粒的 ε-聚己内酯（PCL）薄膜的性能，添加量相同（12wt%）。对复合薄膜的相组成、晶粒尺寸、形貌、表面粗糙度、孔隙率、细胞反应、力学性能和电化学性能进行了分析。每种添加剂都比其他添加剂赋予 PCL 一种或多种物理或生物性能。因此，氧化铝比任何其他添加剂都能更好地提高薄膜的显微硬度，其结果值超过 10MPa。它还导致在基于开路电位（OCP）测量和电化学阻抗谱（EIS）的模拟体液中形成一种具有最小孔隙率和最大降解稳定性的复合材料。二氧化钛使 PCL 的表面最粗糙，这与它的高孔隙率相结合，解释了为什么它最有利于人类成纤维细胞的生长，同时在潮湿、腐蚀性环境中最容易降解，泊松比最高。相比之下，石墨烯使 PCL 的表面最光滑，块状结构的孔隙率最高，但也最导电，OCP 为-37mV。碳酸羟基磷灰石补充的 PCL 的 OCP 最高，为-134mV，机械模量也最高，包括纵向（781MPa）、剪切（106MPa）、块状（639MPa）和弹性（300MPa）。仅用四种无机添加剂沉积多层 PCL 薄膜的唯一好处是能够相对提高抗降解能力。本研究表明，通过简单选择分散在其中的合适无机添加剂，可以有效地优化 PCL 薄膜的性能。没有一种添加剂可以证明对改善 PCL 薄膜所有感兴趣的性能都是理想的，但应根据实际应用调整其选择。在为组织工程应用开发具有优异性能的生物复合材料方面，这种成分优化方法可能证明是至关重要的。
