Ultrasound-Controlled Blood-Brain Barrier (BBB) Opening in a BBB-Glioblastoma Microfluidic Chip for Drug Delivery Studies.

The blood-brain barrier (BBB) is a major obstacle to treating glioblastoma (GBM) by restricting the entry of most therapeutic molecules into the brain. Interspecies differences in BBB structure and function complicate the clinical translation of animal models, highlighting the need for human-relevant in vitro BBB platforms for assessing drug permeability in GBM therapy. Here, a protocol is described for constructing a microfluidic BBB-GBM chip model. This model establishes a tri-culture system comprising human cerebral microvascular endothelial cells (HCMECs), primary astrocytes (ACs), and U87-MG cells within a Matrigel-embedded microfluidic platform. BBB integrity is verified through continuous zonula occludens-1 (ZO-1) immunostaining and FITC-dextran permeability assay. Low-intensity ultrasound (US) (1 MHz, 1 W/cm2, 30 s) is then employed to induce transient and largely reversible BBB opening, allowing tumor-targeting nanomicelles (SFN@RB@SPMs) to efficiently traverse the barrier and accumulate in GBM cells. A key feature of this protocol is the integration of real-time BBB permeability and drug delivery measurements within a single ultrasound-responsive chip, providing a powerful platform to dissect the mechanisms of ultrasound-augmented drug delivery in GBM.