DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056, Aachen, Germany.
Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
Adv Biol (Weinh). 2021 Aug;5(8):e2000427. doi: 10.1002/adbi.202000427. Epub 2021 May 13.
Alveolar-capillary basement membrane (BM) is ultra-thin (<2 µm) extracellular matrix that maintains integral epithelial-endothelial cell layers. In vitro reconstructions of alveolar-capillary barrier supported on synthetic scaffolds closely resembling the fibrous and ultra-thin natural BM are essential in mimicking the lung pathophysiology. Although BM topology and dimensions are well known to significantly influence cellular behavior, conventionally used BM mimics fail to recreate this natural niche. To overcome this, electrospun ultra-thin 2 µm poly(caprolactone) (PCL) nanofibrous mesh is used to establish an alveolar-capillary barrier model of lung endothelial/epithelial cells. Transepithelial electrical resistance (TEER) and permeability studies reveal integral tight junctions and improved mass transport through the highly porous PCL meshes compared to conventional dense membranes with etched pores. The chemotaxis of neutrophils is shown across the barrier in presence of inflammatory response that is naturally impeded in confined regions. Conventional requirement of 3 µm or larger pore size can lead to barrier disruption due to epithelial/endothelial cell invasion. Despite high porosity, the interconnected BM mimic prevents barrier disruption and allows neutrophil transmigration, thereby demonstrating the physiological relevance of the thin nanofibrous meshes. It is envisioned that these bipolar cultured barriers would contribute to an organ-level in vitro model for pathological disease, environmental pollutants, and nanotoxicology.
肺泡毛细血管基底膜 (BM) 是超薄膜(<2 µm)，是维持完整上皮-内皮细胞层的细胞外基质。在体外，使用类似于纤维和超薄天然 BM 的合成支架来重建肺泡毛细血管屏障，对于模拟肺生理学至关重要。尽管 BM 的拓扑结构和尺寸对细胞行为有显著影响，但传统的 BM 模拟物无法再现这种自然生态位。为了克服这一问题，我们使用静电纺丝超薄膜(<2 µm)聚己内酯 (PCL) 纳米纤维网来建立肺内皮/上皮细胞的肺泡毛细血管屏障模型。跨上皮电阻 (TEER) 和通透性研究表明，与具有蚀刻孔的传统致密膜相比，高度多孔的 PCL 网具有完整的紧密连接和改善的质量传输。在存在炎症反应的情况下，中性粒细胞在屏障上表现出趋化性，而在受限区域，炎症反应会自然受到阻碍。由于上皮/内皮细胞的侵袭，传统的 3 µm 或更大孔径的要求可能导致屏障破坏。尽管具有高孔隙率，但互连的 BM 模拟物可防止屏障破坏并允许中性粒细胞迁移，从而证明了超薄纳米纤维网的生理相关性。可以预见的是，这些双极培养的屏障将有助于建立用于病理性疾病、环境污染物和纳米毒理学的器官水平体外模型。
