Nano zero-valent iron driven sodium alginate/poly (acrylic acid) composite hydrogel powder for rapid hemostasis and wound healing

Uncontrollable bleeding resulting from warfare, traffic accidents, and various high-risk industries poses a serious issue. In this study, we develop a nano-zero-valent iron (nZVI)-driven sodium alginate (SA)/polyacrylic acid (PAA) composite hydrogel (SA/PAA/nZVI, SPI), which is subsequently fabricated into a powder to achieve rapid hemostasis and promote wound healing. The redox system comprising nZVI/ammonium persulfate (APS) efficiently generates significant quantities of free radicals and Fe³⁺ under both room and low temperatures (4 °C), thereby significantly accelerating hydrogel formation. The SPI hydrogel exhibits excellent mechanical properties and adhesion due to its interpenetrating network structure, enabling it to resist various degrees of bending and folding. Notably, the SPI hydrogel powder, obtained through drying and grinding processes, possesses self-gelling properties and can effectively adhere to wet tissues. This is attributed to the strong hygroscopic properties of the hydrogel and the abundant dynamic bonds within its structure. These powders can rapidly absorb significant volumes of blood, including blood cells and coagulation factors, and demonstrate superior hemostatic efficacy over commercial chitosan powders (CCS) in diverse bleeding scenarios. Furthermore, the SPI hydrogel powder markedly improved skin wound healing compared to CCS in a rat full-thickness skin wound model. In conclusion, the SA/PAA composite hydrogel, driven by nZVI, demonstrates significant potential for facilitating hemostasis and wound healing.