Exclusive liquid repellency isolation (ELRi) microliter scale isolation technique unmasks T-cell migration defects to CCL21 in pediatric asthma.

Exclusive Liquid Repellency Isolation (ELRi) is a novel, chip-free platform designed for efficient microscale immune cell isolation. Leveraging the inherent exclusive liquid repellency (ELR) properties of polypropylene tubes with an oil overlay, ELRi ensures that small sample volumes, as low as 8 μL, have no contact with container walls, preventing cell loss. Here we describe ELRi and demonstrate magnetic bead-based isolation of diverse immune cells, including T cells, and monocytes, from whole blood. The platform's utility is highlighted in its application to pediatric asthma research, where sample volume is highly restricted. It has been reported that the T cell homing receptor CCR7 is downregulated in cells from asthmatic patients, but a direct functional link to impaired cell migration remains unconfirmed (1, 2). Using ELRi-isolated cells, we provide the first functional evidence that T cells from asthmatic children exhibit significantly impaired chemotaxis toward the CCR7 ligand, CCL21. By simplifying RBC depletion and enabling such functional assays alongside RNA sequencing from the same tiny sample, ELRi overcomes the limitations of large-volume flow cytometry or cell-specific sorting methods. Easily integrated into lab workflows and scalable for various needs, ELRi facilitates more frequent, minimally invasive, and functionally informative immune profiling of restricted volume samples.