A method of treating trauma-induced hemorrhage, comprising administering a hydrogel to a subject in need thereof the hydrogel comprising a cross-linked polymer, the cross-linked polymer comprising cross-links between at least two monomer backbones, wherein at least one monomer comprises a primary, secondary, tertiary or quaternary amine with a pKa of at least 7.4, and capable of displaying a positive electrostatic charge at the pH of blood or plasma (7.4), and wherein the polymer is capable of activating the blood coagulation cascade by inducing fibrin formation,
- wherein the monomer backbones are cross-linked with cross-linkers selected from the group consisting of N—N′-methylene bisacrylamide, N—N′-bisacrylylcystamine, bisacrylyl piperazine, ethylene glycol diglycidyl ether, epichlorohydrin, N—N′-diallyltartardiamide, ethylene glycol dimethacrylate and ethylene glycol diacrylate.