Repairing cartilage defect is always an intractable problem in joint surgery field. Tissue engineering, in the industry, is universally considered as a decent solution for overcoming this challenge. Especially the three-dimensional (3D) scaffolds play a significant role in cartilage repair. Thereinto, the electrospinning has become a very attractive method for the preparation of scaffolds. In recent years. However, these scaffolds are limited in terms of their three-dimensional (3D) applications due to their two-dimensional (2D) structure and pore size which are smaller than a cartilage cellular diameter and thus limit the cellular migration in these structures. To address this issue, this study will present an promising post electrospinning approach that can transform two-dimensional scaffolds into three-dimensional scaffolds via the way of insitu gas foaming within the pores of the nanofiber membranes as the driving force. Our previous study reported that agelatin/polycaprolactone (GT:PCL) ratio of 7:3 might be suitable for the cartilage regeneration [Zheng R, et al The influence of Gelatin/PCL ratio and 3D construct shape of electrospun membranes on cartilage regeneration. Biomaterials 2014;35:152-164]. Therefore, in the present experiment, we chose the above ratio (GT:PCL=7:3) to realize two types of scaffolds (2D and 3D scaffolds) transition via the gas-foaming technique and investigated whether the three-dimensional structure was more conducive to cartilage regeneration than 2D.The experiment results have revealed that 3D scaffolds can achieve a larger pore size, higher porosity and higher biocompatibility than 2D scaffolds. In addition, both scaffolds which were implanted with chondrocytes all had formed mature cartilage-like tissues after 8 weeks of culturing in rabbits, and the 3D scaffold formed a three-dimensional structure, whereas the 2D scaffold only formed a thin layer of cartilage. As the macroscopic and histological results showed after 12 weeks postoperation, in the 2D scaffold group, the defect was full of fibrillar connective tissue, and as shown by HE staining, obviously there is no staining with Saf-O/FG and toluidine blue on the surface of repaired site. On the contrary, in the 3D scaffold group, homogeneous and mature cartilaginous tissue were found in the defect area. The defect was filled with numerous new chondrocytes, and the histologicalstaining revealed a large amount of regenerated cartilage tissue which was perfectly integrated with normal cartilage tissue. The results distinctly indicated that the 3D scaffold led to better cartilage repair effects than the 2D scaffold. Generally speaking, the current study demonstrated that a gas-foaming three-dimensional electrospun nanofiber scaffold would be a potential platform for cartilage regeneration and might provide a potential treatment option for repairing articular cartilage defects.

修复软骨缺损一直是关节外科领域的难题。行业内的组织工程被普遍认为是克服这一挑战的不错的解决方案。特别是三维 (3D) 支架在软骨修复中发挥着重要作用。其中，静电纺丝已成为制备支架的一种非常有吸引力的方法。最近几年。然而，这些支架在其三维 (3D) 应用方面受到限制，因为它们的二维 (2D) 结构和孔径小于软骨细胞直径，因此限制了这些结构中的细胞迁移。为了解决这个问题，这项研究将提出一种很有前景的后静电纺丝方法，该方法可以通过纳米纤维膜孔内的原位气体发泡作为驱动力将二维支架转化为三维支架。我们之前的研究报告称，7:3 的明胶/聚己内酯 (GT:PCL) 比例可能适合软骨再生 [Zheng R,等明胶/PCL 比率和电纺膜的 3D 构建形状对软骨再生的影响。生物材料 2014；35:152-164]。因此，在本实验中，我们选择上述比例（GT:PCL=7:3）通过气体发泡技术实现两种支架（2D和3D支架）的过渡，并研究三维结构是否更实验结果表明，3D支架比2D支架具有更大的孔径、更高的孔隙率和更高的生物相容性。此外，两种植入软骨细胞的支架在兔体内培养8周后均已形成成熟的软骨样组织，3D支架形成三维结构，而2D支架仅形成一层薄薄的软骨。术后 12 周宏观和组织学结果显示，2D 支架组中，缺损处充满纤维状结缔组织，HE染色可见修复部位表面明显未见Saf-O/FG和甲苯胺蓝染色。相反，在3D支架组中，在缺损区域发现了均质和成熟的软骨组织。缺损处充满了大量新的软骨细胞，组织学染色显示大量再生软骨组织与正常软骨组织完美融合。结果清楚地表明，3D 支架比 2D 支架具有更好的软骨修复效果。通常来说，一般来说，