A three‐layered fibrous scaffold composed of fibers of different diameters in each layer was fabricated in correspondence with the structure of the blood vessels. Effect of solution and electrospinning parameters on morphology and diameters of the fibers were investigated by scanning electron microscopy (SEM), for each layer. The SEM images showed that 18% poly (lactic‐co‐glycolic acid) (PLGA)‐gelatin‐chitosan in 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP)/acid acetic solution resulted in bead‐free fibers for the outer layer. For the middle layer, 18% PLGA‐gelatin in HFIP at 13 kV with 13 cm needle to collector distance was chosen as the optimum condition. SEM imaging demonstrated that by increasing graphene content from 0.5 to 2 wt% in the inner layer (as an electrically conductive/platelet anti‐adhesion material), the fiber diameter decreased from 324.01 ± 58.90 to 288.59 ± 70.77 nm. The effect of gelatin crosslinking on the microstructure of the fibers was also examined. Shrinkage ratio decreased from 57 to below 21% upon crosslinking of the three‐layered scaffold in exposure to vapor of 50% glutaraldehyde solution for 2 hours. Mechanical test showed that tensile strength of the crosslinked three‐layer scaffold in the longitudinal direction was 2.90 MPa which is comparable to that of the vein and artery. The MTT [3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] assay displayed cell viability of above 96% for the PLGA‐gelatin containing 2 wt% graphene. SEM analysis revealed that the addition of graphene to PLGA‐gelatin (up to 2%) causes a remarkable improvement in cell adhesion.

中文翻译：

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工程PLGA-明胶-壳聚糖/ PLGA-明胶/ PLGA-明胶-石墨烯三层支架对HUVEC黏附/增殖的影响

根据血管的结构，制作了由三层不同直径的纤维组成的三层纤维支架。通过扫描电子显微镜（SEM）研究每一层的溶液和电纺丝参数对纤维形态和直径的影响。SEM图像显示，在1,1,1,3,3,3-六氟-2-丙醇（HFIP）/酸性乙酸溶液中的18％聚（乳酸-乙醇酸）（PLGA）-明胶-壳聚糖外层无珠子纤维。对于中间层，选择13kV的HFIP中18％PLGA-明胶，针距收集器的距离为13 cm作为最佳条件。SEM成像表明，通过将内层中的石墨烯含量从0.5 wt％增加到2 wt％（作为导电/血小板抗粘材料），纤维直径从324.01±58.90 nm减小到288.59±70.77 nm。还检查了明胶交联对纤维微结构的影响。在暴露于50％戊二醛溶液的蒸气中2小时使三层支架交联后，收缩率从57％降至21％以下。力学测试表明，交联的三层支架的纵向拉伸强度为2.90 MPa，与静脉和动脉的拉伸强度相当。MTT [3-（4,5-二甲基噻唑-2-基）-2-，5-二苯基四唑溴化物]测定显示，含2 wt％石墨烯的PLGA-明胶的细胞活力高于96％。SEM分析表明，向PLGA-明胶中添加石墨烯（最多2％）可显着改善细胞粘附性。还检查了明胶交联对纤维微结构的影响。在暴露于50％戊二醛溶液的蒸气中2小时使三层支架交联后，收缩率从57％降至21％以下。力学测试表明，交联的三层支架的纵向拉伸强度为2.90 MPa，与静脉和动脉的拉伸强度相当。MTT [3-（4,5-二甲基噻唑-2-基）-2-，5-二苯基四唑溴化物]测定显示，含2 wt％石墨烯的PLGA-明胶的细胞活力高于96％。SEM分析表明，向PLGA-明胶中添加石墨烯（最多2％）可显着改善细胞粘附性。还检查了明胶交联对纤维微结构的影响。在暴露于50％戊二醛溶液的蒸气中2小时使三层支架交联后，收缩率从57％降至21％以下。力学测试表明，交联的三层支架的纵向拉伸强度为2.90 MPa，与静脉和动脉的拉伸强度相当。MTT [3-（4,5-二甲基噻唑-2-基）-2-，5-二苯基四唑溴化物]测定显示，含2 wt％石墨烯的PLGA-明胶的细胞活力高于96％。SEM分析表明，向PLGA-明胶中添加石墨烯（最多2％）可显着改善细胞粘附性。在暴露于50％戊二醛溶液的蒸气中2小时使三层支架交联后，收缩率从57％降至21％以下。力学测试表明，交联的三层支架的纵向拉伸强度为2.90 MPa，与静脉和动脉的拉伸强度相当。MTT [3-（4,5-二甲基噻唑-2-基）-2-，5-二苯基四唑溴化物]测定显示，含2 wt％石墨烯的PLGA-明胶的细胞活力高于96％。SEM分析表明，向PLGA-明胶中添加石墨烯（最多2％）可显着改善细胞粘附性。在暴露于50％戊二醛溶液的蒸气中2小时使三层支架交联后，收缩率从57％降至21％以下。力学测试表明，交联的三层支架的纵向拉伸强度为2.90 MPa，与静脉和动脉的拉伸强度相当。MTT [3-（4,5-二甲基噻唑-2-基）-2-，5-二苯基四唑溴化物]测定显示，含2 wt％石墨烯的PLGA-明胶的细胞活力高于96％。SEM分析表明，向PLGA-明胶中添加石墨烯（最多2％）可显着改善细胞粘附性。90 MPa，与静脉和动脉相当。MTT [3-（4,5-二甲基噻唑-2-基）-2-，5-二苯基四唑溴化物]测定显示，含2 wt％石墨烯的PLGA-明胶的细胞活力高于96％。SEM分析表明，向PLGA-明胶中添加石墨烯（最多2％）可显着改善细胞粘附性。90 MPa，与静脉和动脉相当。MTT [3-（4,5-二甲基噻唑-2-基）-2-，5-二苯基四唑溴化物]测定显示，含2 wt％石墨烯的PLGA-明胶的细胞活力高于96％。SEM分析表明，向PLGA-明胶中添加石墨烯（最多2％）可显着改善细胞粘附性。