A 3D microfluidic model of exchange between perfused blood and lymphatic microvascular networks.

Blood and lymphatic microvascular networks function as integrated systems within tissues, exchanging fluid, molecules, and cells to regulate homeostasis and immune responses, yet current in vitro models primarily study these systems in isolation. Existing blood-lymphatic culture models either lack in vivo-like network architecture or cannot achieve independent perfusion of the two vascular compartments, preventing their use in modeling cross-network transport interactions. Here, we present a novel microfluidic platform that supports the formation of independently perfusable, self-assembled blood and lymphatic microvascular networks with physiologically relevant architecture, surface area, and spatial organization. This model was created using a tape-based laminated microfluidic device and sequential gel casting approach to spatially pattern blood and lymphatic endothelial cells within a continuous matrix environment, allowing the two networks to co-develop and become independently perfusable without compromising cross-network transport capacity. High-resolution imaging confirmed that both networks matured progressively over 5 days, maintaining distinct identities, morphology, and barrier integrity under optimized growth factor conditions. Functional validation demonstrated size-selective transport between networks and physiologically relevant T-cell migration from blood to lymphatic vessels, with enhanced trafficking under inflammatory (TNF-α), chemoattractant (SDF-1α), and activation conditions. These studies establish a new experimental platform for the investigation of molecular and cellular transport and signaling across the blood-lymphatic interface under diverse physiological and pathological conditions.