2025 AIChE Annual Meeting

Vascular-Perfusable 3D Human Brain-on-Chip to Model the Blood-Brain Barrier

The blood-brain barrier (BBB) regulates the transport of molecules into the brain and is adversely affected in many neurological diseases. The extreme selective permeability of the BBB, while crucial to its protective function, is also a significant obstacle to the delivery of therapeutics for treating neurological diseases. Our current understanding of the mechanisms governing human BBB function and transport is limited by the in vitro models used to study them. Insights from in vivo rodent model studies of the BBB are not consistently translatable to the human BBB, which exhibits different transcriptional signatures, greater cellular complexity, and more restrictive transport activity compared to other species. Human cell-based in vitro brain models have the potential to capture aspects of human physiology and genetics relevant to human neurological diseases with greater fidelity.

Here we present an in vitro, vascular-perfusable Brain-Chip model building upon our previously established miBrain platform: a 3D co-culture of induced pluripotent stem cell (iPSC)-derived brain microvascular endothelial cells (BMECs), astrocytes, pericytes, oligodendroglia, microglia, and neurons within a hydrogel engineered to support all six cell types. The Brain-Chip model consists of a microfluidic platform to support the formation of lumenized human BBB-mimetic vessel networks and to enable perfusion of solutes across the vasculature of this hydrogel-encapsulated co-culture. We employ an image analysis pipeline to quantify vessel parameters including vessel diameter, branch length, and cross-network permeability from perfusion assays. The Brain-Chip model addresses the challenge of replicating the structural and functional complexity of the human BBB more closely than previously established 2D monolayer, non-perfusable cultures and previously established 3D cultures comprising only a subset of the major brain cell types incorporated in the Brain-Chip.

The generation of cell types within the Brain-Chip model from patient-derived iPSCs enables systematic experimental control and inquiry into genotype-modulated disease pathology across these cell types. We leverage the Brain-Chip platform to study the role of APOE4, the strongest known genetic risk factor for Alzheimer’s disease, on human BBB function. We demonstrate alterations in vascular networks within Brain-Chip systems constructed using APOE4-positive cell types consistent with observations of BBB dysfunction in human APOE4 carriers, further validating the Brain-Chip as a useful model for investigating biological mechanisms involved in human BBB function and assessing potential therapeutic avenues for neurological diseases.