SBIR Phase II: Sprayable Reversible Hemostat for Treatment of Non-Compressible Hemorrhage

This Small Business Innovation Research (SBIR) Phase II project aims to develop a sprayable foam hemostat for treatment of non-compressible hemorrhage, which is the leading cause of death (~90%) for bleeding-related trauma. The foam material is based on the biopolymer chitosan; a modification to this polymer with novel hydrophobic grafts allows the material to clot blood much more rapidly and adhere to tissue more strongly than the unmodified version. Also, a complementary cyclodextrin-based technology is able to reverse the hemostatic action of the modified chitosan on demand. The biopolymer is packaged into aluminum hand-held canisters with liquefied propellant and expelled via mechanical actuator creating a foam which is able to expand into irregularly shaped cavities. The desired outcome of the project is to develop a working prototype of the canister containing an optimized modified chitosan with respect to hydrophobic grafting density and hydrophobe length. Foam formulations will be tested for clotting and reversibility in vitro via dynamic and steady shear rheology studies in the presence of blood and in vivo using non-compressible bleeding models in pigs. Biocompatibility testing and tissue histology studies will be performed to determine the safety profile of the optimized formulations. The broader impact/commercial potential of this project falls in the arena of battlefield and trauma medicine. Foams are the future of acute wound treatment on the battlefield and in emergency medical services. Severe bleeding, especially internal bleeding, is not easily treated with a spatially contained product, such as a bandage. Furthermore, correct bandage placement on an acute wound requires a great deal of skill and experience. However, a sprayable foam is very user friendly and allows potential for adequate self-application or application by an unskilled 'buddy' for a wide range of hemorrhage types. Thus, we envision our chitosan foam as a necessary supply in the soldier's backpack, the emergency room and the home first aid kit. This vision is a viable economic prospect because the material is low cost, lightweight and highly durable even in extreme ambient conditions. Additionally, the reversibility provided by the complementary cyclodextrin system provides a streamlining tool for the trauma surgeon. Removal of hemostatic material and precise indentification of the injury site are necessary tasks in the operating room which are made much easier by this unique technological feature.