When we suffer a wound, our body initiates the clotting cascade at the wound site, which ultimately results in a clot, i.e., a protein gel, that immobilizes blood cells and thereby achieves hemostasis. Gelation of blood is thus critical to hemostasis, and the need for an effective hemostat is particularly important in the case of soldiers on the battlefield. Here, we demonstrate the ability to gel blood using a self-assembling biopolymer. The biopolymer is a hydrophobically modified (hm) derivative of the polysaccharide, chitosan. When hm-chitosan is contacted with heparinized human blood, it rapidly transforms the liquid into an elastic gel. In contrast, the native chitosan (without hydrophobes) does not gel blood. Gelation occurs because the hydrophobes on hm-chitosan insert into the membranes of blood cells and thereby connect the cells into a sample-spanning three-dimensional network. We are currently evaluating hm-chitosan as an effective, yet low-cost hemostat for use by trauma centers and the military. Several embodiments of hm-chitosan have been tested, including solutions, bandages, and foams. Preliminary tests with small and large animal injury models show the efficacy of these hm-chitosan-based systems at achieving rapid hemostasis, even for severe life-threatening injuries. [Reference: Dowling et al., Biomaterials, 32, 3351 (2011).]

Designing a new generation of polymeric hemostats that can rapidly stop bleeding from serious wounds

245th National Meeting (2013)

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