Biofabrication of a glomerular filtration barrier model through a biomimetic fibrous membrane to mimic functional core components

Abstract text (incl. figure legends and references)

The kidney is a highly dynamic organ involved in blood ultrafiltration, hence prone to failure mainly arising from the glomerulus. Filtration occurs through the glomerular filtration barrier (GFB), a tri-layer interface composed of glomerular endothelial cells (GEC), podocytes, and the glomerular basement membrane. Hence, damage to any component of GFB could result in failure of the barrier function, causing proteinuria and kidney disease. This study is aimed at designing a biomimetic artificial basement membrane exploited for the cross-membrane culture of GECs and podocytes and establishing a tri-layer barrier to investigate cell behavior under static and dynamic culture conditions. Firstly, we electrospun nanofibers with random and aligned morphology. Then, the fibers were functionalized with gelatin using polydopamine chemistry to improve cell adhesions. The nanofibers were characterized using SEM, microBCA, and Raman analysis. Thereafter, we established a monolayer of GECs and podocytes on either side of the membranes. Later the membrane was tested under dynamic conditions of flow in a bioreactor. The electrospun mat presents an average thickness of 7 µm, average fiber diameter of 0.6 µm; alignment was present in 86% of the fibers. Porosity of the mat was 43% and 37% for random and aligned. Gelatin release quantified over 21 days was 40 µg/cm². Cells spread and attached on all tested membranes but indicate an elongated morphology and the formation of a monolayer on the aligned nanofibers. After culturing under flow, filtration is tested in terms of barrier function to albumin. These results confirmed that a surface functionalized artificial GBM can support a co-culture of glomerular cells to model the glomerular functions.