Elegans-Inspired Magnetic Polyurethane Soft Robot (MPSR) for Closed Visceral Secondary Hemostasis In Situ.

Secondary hemorrhage is inevitable during the transportation of casualties in harsh environments, and reoperative treatment entails severe adverse effects that inflicts cumulative traumatic damage on the body. Inspired by elegans, we engineered a magnetic polyurethane soft robot (MPSR) that exhibited excellent timely and secondary hemostatic efficacy for closed visceral injuries and possessed the unique capability to address the aforementioned challenges. These superior performances were attributed to the switchable dormant and active states of MPSR, which endowed it with outstanding long-distance injectability and deformability. For closed hemostasis, contrast-enhanced ultrasound (CEUS)-guided percutaneous puncture technology was employed, through which MPSR achieved hemostasis via an 18G puncture needle under the synergistic action of heat and shear force. In the secondary hemorrhage, the transition of MPSR between its dormant and active states was regulated by the magnetothermal effect. The MPSR in the active state can be non-contactly driven to undergo in situ deformation and movement, re-diffuse and fill the bleeding site, and then revert to the dormant state for stable maintenance. These findings highlighted the advantages of MPSR in the nonsurgical management of secondary hemorrhage and underscored its great potential for clinical application.