Towards a stackable kidney-on-a-chip model with morphogen patterning for nephron segment differentiation

Abstract

Recapitulating multiple regions of the nephron remains a challenge with current organ-on-a-chip strategies. However, patterned nephron systems can provide insight into mechanisms of disease and induce spatially regulated differentiation of stem cells and organoids into tissues with nephron segments. We have created three kidney-on-a chip devices with physical and chemical nephron patterning. In Aim 1, we developed a stackable nephron-on-a-chip with hydrogel layers open on both sides of the device. This enables the integration of multiple cell types and tissue structures by adding layers to the system. In Aim 2, we created an external gradient generator to apply morphogenetic gradients using source-sink diffusion to collagen-based microphysiological systems, such as the model developed in Aim 1. In Aim 3, we established a nephron-on-a-chip with interstitial flow patterning to apply growth factor concentrations to defined regions along a lumenized microchannel. These systems require optimization for longer-term cell culture, hydrogel stability, and perfusion at incubation temperatures. Future work includes coculturing nephron cell types through stacked tissues in the Aim 1 device. Moreover, spatially-directed nephron progenitor cell (NPC) differentiation can be studied within the Aim 2 and Aim 3 systems.