Versatile Nano‐Crosslinker Enhanced Injectable Hydrogel Toward Rapid Hemostasis and Efficient Trauma Repair

Uncontrolled traumatic hemorrhage, often complicated by infection and poor healing, accounts for over 30% of trauma‐related deaths worldwide. Injectable hydrogels with robust multi‐bond crosslinked networks, integrating fluidity and in situ stability, are promising for efficient hemostasis, but their crosslinkers’ relatively single structures limit the multifunctionality required for effective trauma management in resource‐scarce environments. Herein, a new class of versatile ε‐polylysine grafted manganese dioxide (EPL‐ g ‐MnO 2 ) nano‐crosslinkers is synthesized to construct an injectable hydrogel (i.e., OSEG hydrogel). Driven by EPL‐ g ‐MnO 2 , OSEG hydrogel rapidly achieves stable wet adhesion and efficient hemostasis in critical injuries (e.g., 24.9 s in a rabbit model of cardiac hemorrhage) via imine, hydrogen, and ionic bonds, which form a robust and multifunctional crosslinked network upon full gelation. In the microenvironment of traumatic wounds, OSEG hydrogel undergoes accelerated degradation to further expose EPL‐ g ‐MnO 2 and spermidine, thereby providing sufficient antibacterial and pro‐healing effects. As a result, OSEG hydrogel achieves a bone volume/total volume 3.3 times that of commercial hemostat SURGIFLO in a rat model of infected cranial defect. This work may inspire the design of advanced injectable hydrogels for synergistic trauma management.