A human iPSC-based perfusable and membrane-free neurovascular unit-on-chip connecting brain organoids to the blood-brain barrier.

Abstract

The blood-brain barrier (BBB) protects the central nervous system by restricting entry of harmful blood-borne factors, but this selectivity actively limits delivery of therapeutics to the brain. Because BBB function is shaped by dynamic interactions within the neurovascular unit (NVU), particularly between brain endothelial cells, pericytes, and astrocytes, there is a need for human-relevant models that capture both barrier properties and neurovascular crosstalk in a controlled setting. Here, we present a novel human induced pluripotent stem cell (iPSC)-based NVU-on-chip that couples a perfusable, vessel-like BBB compartment to an adjacent open-top chamber housing a human brain organoid (hBO) via a membrane-free, hydrogel-based interface. This design enables co-culture of BBB and parenchymal components in close proximity while allowing direct cell-cell interactions at the barrier-tissue boundary without an artificial porous membrane. Using this platform, we demonstrate stable on-chip co-culture and show that hBO-derived astrocytes can sprout, migrate toward the BBB compartment and establish direct contact with endothelial cells, recapitulating the NVU structure. This system offers a human-specific framework for modeling NVU biology in health and disease and for evaluating BBB penetration together with downstream effects of candidate therapeutics on hBO.