Background. Tissue engineering of cartilage requires the selection of an appropriate artificial scaffold. Polylactic acid (PLA) honeycomb films are expected to be highly biodegradable and cell adhesive due to their high porosity. The purpose of this study was to determine the optimal pore size of honeycomb PLA films for in vitro cartilage formation using synovial mesenchymal stem cells (MSCs). Methods. Suspensions of human synovial MSCs were plated on PLA films with different pore sizes (no pores, or with 5 μm or 20 μm pores) and then observed by scanning electron microscopy. The numbers of cells remaining in the film and passing through the film were quantified. One day after plating, the medium was switched to chondrogenic induction medium, and the films were time-lapse imaged and observed histologically. Results. The 5 μm pore film showed MSCs with pseudopodia that extended between several pores, while the 20 μm pore film showed MSC bodies submerged into the pores. The number of adhered MSCs was significantly lower for the film without pores, while the number of MSCs that passed through the film was significantly higher for the 20 μm pore film. MSCs that were induced to form cartilage peeled off as a sheet from the poreless film after one day. MSCs formed thicker cartilage at two weeks when growing on the 5 μm pore films than on the 20 μm pore films. Conclusions. Honeycomb PLA films with 5 μm pores were suitable for in vitro cartilage formation by synovial MSCs.

中文翻译：

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用于滑膜间充质干细胞体外软骨形成的蜂窝状聚乳酸薄膜的最佳孔径

背景。软骨组织工程需要选择合适的人工支架。聚乳酸 (PLA) 蜂窝膜由于其高孔隙率而有望具有高度的可生物降解性和细胞粘附性。本研究的目的是使用滑膜间充质干细胞 (MSCs) 确定用于体外软骨形成的蜂窝 PLA 薄膜的最佳孔径。方法。将人滑膜 MSC 悬浮液镀在具有不同孔径（无孔，或 5  μm或 20  μm ）的 PLA 薄膜上m 孔），然后通过扫描电子显微镜观察。量化留在薄膜中并穿过薄膜的细胞数量。电镀一天后，将培养基切换到成软骨诱导培养基，并对薄膜进行延时成像和组织学观察。结果。5μm 孔膜显示MSCs具有在多个孔之间延伸的伪足，而 20μm孔膜显示MSC体浸没在孔中。无孔薄膜粘附的 MSCs 数量显着降低，而 20  μm薄膜通过薄膜的 MSCs 数量显着增加m 孔膜。一天后，被诱导形成软骨的MSC从无孔膜上剥落成薄片。MSCs 在 5 μ m 孔膜上比在 20  μ m 孔膜上生长两周时形成更厚的软骨 。结论。具有 5 μ m 孔的蜂窝状 PLA 薄膜 适用于滑膜 MSCs 的体外软骨形成。