Targeted delivery of hemostats to complex bleeding wounds with magnetic guidance for instant hemostasis

Abstract

Precise and instant hemorrhage control of complex bleeding wounds (narrow, perforating, and irregular) remains a challenge as existing hemostats halt bleeding at the wound surface rather than at the injured vessels. In this study, a hemostat (MS@Fe4-BT) guided by magnetic fields (MFs) is developed to deliver therapy into a targeted site. MS@Fe4-BT employs microporous starch particle as the base substrate, Fe3O4 as the driving system, bovine serum albumin as the medium for drug loading, and thrombin as the hemostatic drug. According to self-assembly experiments and animal tests, MS@Fe4-BT can spontaneously assemble into microparticle chains to move under the application of MFs and can be directed into narrow and bent wound channels to halt bleeding instantly, which cannot be realized with existing hemostats. The hemostatic times for the “V”- and “J”-shaped wounds in the liver and the V-shaped wounds in the femoral artery are 37, 44, and 152 s, respectively. Moreover, the excellent biosafety of MS@Fe4-BT is demonstrated with systematic assessments (hemolysis, cytotoxicity, biodegradation). Therefore, this study provides a new thought for the hemorrhage control of bleeding wounds in complex environments. To our knowledge, this is the first reported study on the MF-guided delivery of hemostats to injured vessels.