Membrane composition modulates podocyte-renal endothelial cell interactions in a humanized glomerular basement...

Reconstructing the glomerular filtration barrier in vitro remains a major challenge in kidney research due to the complexity of cellular interactions and membrane properties that regulate glomerular function. In this study, we developed and characterized a human glomerulus-on-a-chip model that recapitulates podocyte-glomerular endothelial cell (ciGEnC) interactions across a membrane resembling the native glomerular basement membrane (GBM). Using polyethersulfone (PES) and polyethylene terephthalate (PET) membranes with distinct physicochemical characteristics, we systematically evaluated how membrane composition modulates cellular attachment, spatial organization, and extracellular matrix (ECM) accumulation and cellular organization at the podocyte-endothelial interface under static and dynamic conditions. PES membranes promoted enhanced adhesion, spreading, and confluence of both podocytes and ciGEnCs. Quantitative fluorescence image analysis revealed significantly higher total cell areas for both cell types on PES compared to PET, with a more balanced endothelial-to-podocyte area ratio (1.77 for PES vs. 3.11 for PET), suggesting improved co-culture equilibrium. The broader pore size distribution, higher equilibrium water content, and elevated nonfreezable water content in PES membranes contributed to stable hydration layers that facilitated cell migration, interaction, and ECM deposition. Confocal imaging demonstrated the formation of continuous, opposing monolayers on PES membranes and ECM accumulation at the interface between the two cell layers. Under physiologically scaled flow rates, both membranes sustained cell attachment and morphology, but PES provided greater resistance to shear-induced detachment, further confirming its suitability for perfusion-based glomerular models. This study highlights the critical role of membrane material properties especially non-freezable hydration capacity and pore morphology in guiding glomerular cell behavior and tissue architecture formation. Our findings establish PES-based GBM microfluidic chips as a promising platform for modeling glomerular filtration, representing an important step toward the development of more physiologically relevant glomerular microfluidic models.