Dual-Driven Hemostats Featured with Puncturing Erythrocytes for Severe Bleeding in Complex Wounds.

Achieving rapid hemostasis in complex and deep wounds with secluded hemorrhagic sites is still a challenge because of the difficulty in delivering hemostats to these sites. In this study, a Janus particle, SEC-Fe@CaT with dual-driven forces, bubble-driving, and magnetic field- (MF-) mediated driving, was prepared via in situ loading of Fe 3 O 4 on a sunflower sporopollenin exine capsule (SEC), and followed by growth of flower-shaped CaCO 3 clusters. The bubble-driving forces enabled SEC-Fe@CaT to self-diffuse in the blood to eliminate agglomeration, and the MF-mediated driving force facilitated the SEC-Fe@CaT countercurrent against blood to access deep bleeding sites in the wounds. During the movement in blood flow, the meteor hammer-like SEC from SEC-Fe@CaT can puncture red blood cells (RBCs) to release procoagulants, thus promoting activation of platelet and rapid hemostasis. Animal tests suggested that SEC-Fe@CaT stopped bleeding in as short as 30 and 45 s in femoral artery and liver hemorrhage models, respectively. In contrast, the similar commercial product Celox™ required approximately 70 s to stop the bleeding in both bleeding modes. This study demonstrates a new hemostat platform for rapid hemostasis in deep and complex wounds. It was the first attempt integrating geometric structure of sunflower pollen with dual-driven movement in hemostasis.