Harnessing micrometer-scale tPA beads for high plasmin generation and accelerated fibrinolysis

Rapid restoration of blood flow is critical in treating acute ischemic stroke. Current fibrinolytic therapies using tissue plasminogen activator (tPA) are limited by low recanalization rates and risks of off-target bleeding. Here, we present a strategy using tPA immobilized on micrometer-scale beads to enhance local plasmin generation. We synthesized tPA-functionalized beads of varying sizes (0.1 μm and 1.0 μm) and evaluated their efficacy. In vitro assays demonstrated that 1.0 μm tPA-beads generated higher plasmin generation compared to free tPA and 0.1 μm beads, overcoming antiplasmin inhibition and promoting a self-propagating wave of fibrinolysis. In a murine model of acute ischemic stroke, intravenous administration of 1.0 μm tPA-beads at doses nearly two orders of magnitude lower than the standard free tPA dose led to rapid and near-complete thrombus removal within minutes. This approach addresses kinetic and transport limitations of current therapies and may reduce the risk of hemorrhagic complications.