Evaluation of Viscoelastic Properties, Blood Coagulation, and Cellular Responses of a Temperature-Sensitive Gel for Hemostatic Application

A facile way to fabricate a thrombin immobilized composite sponge with dual hemostatic effects for acute hemorrhage control

Uncontrolled bleeding and excessive blood loss stand as the leading causes of death in complex surgeries, civilian traumas, and military operations. Sponges have been used for developing efficiency hemostats, but most commonly used hemostatic sponges possess only one single coagulation mechanism or lack inherent blood clotting ability. Herein, we proposed simple yet innovative approaches for creating novel hemostatic composite sponges with dual hemostatic effects. Bacterial cellulose (BC) was first introduced into polyvinyl alcohol (PVA) matrix to develop a BC/PVA (CP) sponge featuring a unique cellulose-embedded porous network structure and desirable properties. Subsequently, thrombin was immobilized on CP through an easy method that combines physical adsorption and covalent binding to fabricate thrombin-carrying CP (TCP) composite sponges. The resulting composites boasted a highly porous structure, outstanding liquid-absorption capacity, low hemolysis rate, and superior biocompatibility. In vitro clotting tests revealed that TCP displayed potent coagulation capabilities, a rapid blood absorption rate, and the ability to stimulate and activate blood components along with the coagulation cascade. In vivo hemostatic assessments further confirmed that TCP offered high hemostatic efficiency and multifaceted hemostatic effects, making it suitable for the management of acute and severe bleeding.

Hemostatic dressings based on poly(vinyl formal) sponges

The development of novel hemostatic agents is related to the fact that severe blood loss due to hemorrhage continues to be the leading cause of preventable death of patients with military trauma and the second leading cause of death of civilian patients with injuries. Herein we assessed the hemostatic properties of porous sponges based on biocompatible hydrophilic polymer, poly(vinyl formal) (PVF), which meets the main requirements for the development of hemostatic materials. A series of composite hemostatic materials based on PVF sponges with different porosities and fillers were synthesized by acetalization of poly(vinyl alcohol) with formaldehyde. Nano-sized aminopropyl silica, micro-sized calcium carbonate, and chitosan hydrogel were used to modify PVF matrixes. The physicochemical properties (pore size, elemental composition, functional groups, hydrophilicity, and acetalization degree) of the synthesized composite sponges were studied by gravimetrical analysis, optical microscopy, scanning electron microscopy combined with energy dispersive x-ray spectroscopy, infrared spectroscopy, and nuclear magnetic resonance. Hemostatic properties of the materials were assessed using a model of parenchymal bleeding from the liver of white male Wistar rat with a gauze bandage as a control. All investigated PVF-based porous sponges showed high hemostatic activity: upon the application of PVF-samples the bleeding decreased within 3 min by 68.4-94.4% (р < 0.001). The bleeding time upon the application of PVF-based composites decreased by 78.3-90.4% (p < 0.001) compared to the application of well-known commercial product Celox™.