Standard and hybrid polymer nanocomposites based on poly(ɛ-caprolactone) (PCL), hydroxyapatite (HAp) and graphene oxide (GO). The GO synthetized here is made up of multilayer graphene oxide (mGO), in which up to five layers are stacked and lateral size around of 1 µm. The nanocomposites (PCL/Hap, PCL/mGO and PCL/HAp/mGO) were prepared by melt mixing in a twin-screw extruder and characterized by mechanical test, transmission electron microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), contact angle (CA), surface zeta potential by streaming and cell proliferation. The HAp content was maintained at 20% (w/w) while mGO was used at three levels of content (0.05, 0.1, and 0.3 w/w). In terms of bulk properties, the presence of mGO even in very low content (0.05 to 0.3%) was very effective in order to increase mechanical properties of PCL (stress and strain at beak and tenacity) while HAp tends to decrease them. When the two fillers are inserted mGO act to recover the properties lost by the presence of HAp. TEM images showed single GO sheets very well dispersed alone or combined with HAp. For surface properties, significant changes have been achieved by the presence of mGO, HAp and mGO/HAp. The water contact angle drops to values below 90° for all nanocomposites making the material hydrophilic, but again by the presence of only 0.05% of mGO it was reached easily. Surface ξ-potential for all nanocomposite was lower than neat PCL. As a consequence of surface modifications improvements in cell proliferation ability could be also observed. All modification by the presence of GO point out these materials as excellent candidates to resorbable suture, drug delivery system, and bone graft substitutes.

中文翻译：

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基于聚ε-己内酯，羟基磷灰石和氧化石墨烯的聚合物纳米复合材料

基于聚（ε-己内酯）（PCL），羟基磷灰石（HAp）和氧化石墨烯（GO）的标准和杂化聚合物纳米复合材料。此处合成的GO由多层氧化石墨烯（mGO）组成，其中最多堆叠五层，横向尺寸约为1 µm。通过在双螺杆挤出机中熔融混合制备纳米复合材料（PCL / Hap，PCL / mGO和PCL / HAp / mGO），并通过机械测试，透射电子显微镜（TEM），红外光谱（FTIR），X射线表征衍射（XRD），接触角（CA），通过流动和细胞增殖的表面ζ电势。HAp含量保持在20％（w / w），而mGO以三种含量水平（0.05、0.1和0.3 w / w）使用。就整体性质而言，即使含量非常低（0.05至0，也存在mGO）。3％）对于提高PCL的机械性能（喙和强度时的应力和应变）非常有效，而HAp则倾向于降低它们。当插入两种填料时，mGO起作用以恢复由于存在HAp而丧失的特性。TEM图像显示单个GO片单独或与HAp结合时非常分散。对于表面性质，通过存在mGO，HAp和mGO / HAp已经实现了重大变化。所有纳米复合材料的水接触角均降至90°以下，从而使该材料具有亲水性，但再次由于仅存在0.05％的mGO，很容易达到。所有纳米复合材料的表面ξ电位均低于纯PCL。作为表面修饰的结果，还可以观察到细胞增殖能力的提高。