Poster O2 - Stopping Bleeding via Sandcastles: Biopolymer Granules form a Sandcastle-Like Gel Around a Wound by Capillary Adhesion

Introduction: Effective bleeding control is crucial in surgical and trauma settings as it can significantly reduce mortality and improve recovery outcomes. Here, we explore granules of a modified chitosan derivative, hydrophobically modified chitosan (hmC), to facilitate this crucial need [1-4]. Upon contact with blood, these granules transition into a gel-like state by capillary adhesion. This is akin to common granular structures found in nature, such as sandcastles on a beach. The resulting granular gel is sufficiently robust that it forms a seal around the wound, thereby stopping the bleeding.

Materials and

Methods: hmC was synthesized by modifying chitosan with hydrophobic n-alkyl tails. Both the degree of hydrophobic modification as well as the chain length of the hydrophobes were varied. Subsequently, the hmC was dried to granular powders and sieved to specific sizes. Mechanical properties of the granular gels were assessed by dynamic rheology studies. Burst-pressure testing was conducted to evaluate gel adhesion to tissue. Finally, degradation of the gels was tested in vitro using chitosanase, a hydrolytic enzyme that cleaves chitosan chains.

Results, Conclusions, and Discussions: Granules of hmC form a gel upon contact with blood at the site of a wound (Figure 1). The hmC granules are applied to the bleeding injury and, after 3 min compression with gauze, the bleeding has stopped due to the formation of the granular gel. This gel exhibits robust mechanical properties, thereby achieving hemostasis. Burst-pressure testing revealed strong adhesion of the gel to the tissue, indicating its potential for stopping bleeding during surgical applications. In vitro degradation studies demonstrated tunable degradation times, offering versatility in clinical use.

Our research highlights the mechanism and promising properties of hmC granules as a new and innovative hemostat.

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