Unilateral thermosensitive Janus hemostatic dressing for matching coagulation physiological processes

Hemostatic dressings are a simple and effective method for managing bleeding emergencies. Based on the blood coagulation process, hemostatic dressings work optimally by aggregating hemocytes and releasing coagulation factors, sealing blood in a sequential manner. Janus materials, which have different compartmentalized components, have the ability to independently perform multiple functions. In this study, a Janus nonwoven fabric with thermo-sensitivity on one side, is designed to be consistent with the physiological process of coagulation. When utilized for hemostasis, the poly(<i>N</i>-isopropylacrylamide) (PNIPAM) side of the Janus material undergoes a phase transition within 1 minute. Prior to this, it adsorbs blood at the injured site and aggregates hemocytes to form a primary thrombus; afterwards, it helps sealing the site to decrease blood loss. During this process, the bioactive glass (BG) side continuously releases SiO₄^4- and Ca²⁺ to activate coagulation factors and accelerate the cascade reaction. The phase transition and hydrophilic/hydrophobic transition of the material are triggered by body temperature and are rapidly completed, just like clicking a switch. In a rat femoral artery model, the blood loss using Janus BG-PNIPAM was only 0.15 g, which is 17.4% and 20.0% the blood loss level achieved by CN and QuikClot® gauze, respectively. Furthermore, the biosafety profile of Janus BG-PNIPAM provides assurance for potential clinical applications.