Super-expandable dual-crosslinking all-cellulose sponge: a physical and chemical solution for hemostasis in severe hemorrhage.

Uncontrolled hemorrhages pose severe threats to life, especially in the case of deep cavity wounds. To address these challenges, we developed an injectable and super-expandable all-cellulose based sponge by dual-crosslinking of needle-leaf pulp fiber (Pulp) with carboxymethyl cellulose (CMC) through a double pore generation strategy. When addressing severe hemorrhage, Pulp-CMC sponge with high porosity can rapidly expand to ∼3900 % of itself in height, applying extra physical pressure to the wounds to stop bleeding, which is highest expansion ratio that ever reported in hemostasis materials. Moreover, the carboxyl groups in CMC can bind with Fe ions in blood, thereby providing a chemical hemostatic effect. In pig femoral artery bleeding and stab wound models, the Pulp-CMC5 sponge reduced bleeding volume by 81 % and 86 %, compared with gauze, respectively. When buried in soil, the sponge can fully degrade within 30 days. The benign strategy retains the biochemical property of biomass to large extent, and the outstanding performance of these sponges provides an alternative "green" hemostasis material for managing uncontrollable bleeding in clinical applications.