Biomimetic Blood-Brain Barrier Model Engineered via Cell Sheet Technology and Microfluidics

The blood-brain barrier (BBB) is a selectively permeable interface essential for preserving brain homeostasis, which also presents a major obstacle to drug delivery in central nervous system (CNS) disorders such as Alzheimer’s disease and brain tumors. Due to the limitations of traditional in vivo studies and the high costs of clinical trials, there is growing interest in high-fidelity in vitro BBB models for early-stage drug screening and development. In this study, we developed a physiologically relevant BBB model by integrating cell sheet engineering with a microfluidic dynamic culture system. To establish the model, we used human brain microvascular endothelial cells (HBMECs), human brain vascular pericytes (HBVPs), and human astrocytes (HAs) grown in a layered fashion to enable cell-cell communication. We optimized the culture and maintenance conditions to obtain an in vitro platform that comprises essential elements of the BBB such as multicellularity, specific cellular order, three-dimensionality, and differentiated basement membrane. Moreover, we demonstrate that the CSE-BBB is handleable and convenient to use in different setups - we assessed the model in static conditions and in a microfluidic device where the exposure to flow resulted in a lower permeability, adjustment of cell morphology and expression of cell-specific genes and proteins needed for the BBB function. Finally, the use of the CSE-BBB model in the glioblastoma scenario was also demonstrated and validated. 

Cell sheet technology enabled the co-culture of endothelial cells, pericytes, and astrocytes, replicating the native BBB architecture, enhancing cell–cell interactions, and eliminating the need for synthetic membranes by promoting endogenous extracellular matrix (ECM) production. On the other hand, incorporation of microfluidics provided physiological shear stress, which promoted tight junction formation, decreased barrier permeability, and improved the model's responsiveness to drug cytotoxicity. Together, these innovations offer a robust and dynamic platform for CNS drug testing, advancing the development of more effective therapies for neurological diseases.