3D printed tubulointerstitium chip as an in vitro testing platform

Chronic kidney disease (CKD) ranks as the twelfth leading cause of death worldwide and represents a major global health problem with still rather limited treatment options. The development of new in vitro models replicating defined segments of the kidney functional units, i.e., the nephrons, in a physiologically relevant and reproducible manner could facilitate drug testing and development. We aimed at producing an in vitro organ-on-a-chip platform with extrusion-based 3D printing approach with sacrificial components. We optimized the manufacturing of the tubular platform produced by printing sacrificial fibers in varying diameters, which provide a suitable structure for cell adhesion and proliferation. The manufactured chip platform was seeded with primary murine tubular epithelial cells and human umbilical vein endothelial cells. The effect of channel geometry, its reproducibility, coatings for optimal cell adhesion, and specific cell markers were investigated. The developed chip presents single and dual channels, mimicking segments of a renal tubule and the capillary network. Together with an extracellular matrix gel analogue placed in the middle of the two channels we aimed at mimicking the renal tubulointerstitium in vitro. The proposed 3D printed platform enables perfusable circular cross-section channels with fully automated, rapid and reproducible manufacturing processes at low costs. In conclusion, this kidney tubulointerstitium on-a-chip provides the first step toward the production of more complex in vitro models for drug testing and identification. This article is protected by copyright. All rights reserved.