3D Lung-on-Chip Model Based on Biomimetically Microcurved Culture Membranes

Abstract

A comparatively straightforward approach to accomplish more physiological realism in organ-on-a-chip (OoC) models is through substrate geometry. There is increasing evidence that the strongly, microscale curved surfaces that epithelial or endothelial cells experience when lining small body lumens, such as the alveoli or blood vessels, impact their behavior. However, the most commonly used cell culture substrates for modeling of these human tissue barriers in OoCs, ion track-etched porous membranes, provide only flat surfaces. Here, we propose a more realistic culture environment for alveolar cells based on biomimetically microcurved track-etched membranes. They recreate the mainly spherical geometry of the cells’ native microenvironment. In this feasibility study, the membranes were given the shape of hexagonally arrayed hemispherical microwells by an innovative combination of three-dimensional (3D) microfilm (thermo)forming and ion track technology. Integrated in microfluidic chips, they separated a top from a bottom cell culture chamber. The microcurved membranes were seeded by infusion with primary human alveolar epithelial cells. Despite the pronounced topology, the cells fully lined the alveoli-like microwell structures on the membranes’ top side. The confluent curved epithelial cell monolayers could be cultured successfully at the air−liquid interface for 14 days. Similarly, the top and bottom sides of the microcurved membranes were seeded with cells from the Calu-3 lung epithelial cell line and human lung microvascular endothelial cells, respectively. Thereby, the latter lined the interalveolar septum-like interspace between the microwells in a network-type fashion, as in the natural counterpart. The coculture was maintained for 11 days. The presented 3D lung-on-a-chip model might set the stage for other (micro)anatomically inspired membrane-based OoCs in the future.

Development and evaluation of a bovine lung-on-chip (bLOC) to study bovine respiratory diseases

“…Other researchers have dramatically changed the micro-landscape of the lung chip through the introduction of micro-curved porous membranes, generating a concave culture surface. Although most applicable to the alveolar region, it is worth exploring this concept for modelling the bronchiolar region of the lung, particularly since the use of a curved surface appears to affect cell density and epithelial layer thickness [ 50 ].…”

The Synergy of Electrospinning and Imprinting for Faithful Replication of Fiber Structures

“…Within biological organisms, nonplanar, curvilinear surfaces are dominating. [ 21 ] The interplay between nonplanar cell substrates and their guidance on morphological and functional cellular response has been highlighted in many studies using, e.g., lung epithelial cells, [ 36 ] bone marrow stromal cells, [ 37 ] and corneal stromal cells. [ 38 ] Therefore, fabricating surface topographies on nonplanar instead of planar substrates is highly relevant.…”

Biomimetic In Vitro Lung Models: Current Challenges and Future Perspective

“…Recently, a new approach using micro‐thermoforming has been utilized to shape the porous PC membrane to microwells. [ 38 ] Another method leveraged sacrificial alginate in a gelatin methacryloyl (GelMA)/alginate hydrogel to generate the geometry of the alveolar sacs. [ 39 ] Although these models have demonstrated a new perspective to manufacture a suitable microenvironment for the pulmonary cells, they also compromised the biological aspects by using a simple monoculture of epithelial cells, mainly cell lines.…”