Thermoresponsive shear-thinning hydrogel (T-STH) hemostats for minimally invasive treatment of external hemorrhages

Clotting Blood into an Adhesive Gel by Hemostatic Powder Based on Cationic/Anionic Polysaccharides and Laponite

Hemostatic powder is widely employed for emergency bleeding control due to its ability to conform to irregularly shaped wounds, ease of use, and stable storage. However, current powders exhibit limited tissue adhesion and insufficient support for thrombus formation, making them easily washed away by blood. In this study, a hybrid powder (QAL) was produced by mixing quaternized chitosan (QCS) powder, catechol-modified alginate (Cat-SA) powder, and laponite (Lap) powder. Upon addition of QAL, the blood quickly transformed to a robust and adhesive blood gel. The adhesion strength of the blood gel was up to 31.33 ± 1.56 kPa. When compared with Celox, QAL showed superior performance in promoting hemostasis. Additionally, QAL exhibited effectiveness in eliminating bacteria while also demonstrating outstanding biocompatibility with cells and blood. These favorable properties, including strong coagulation, adhesion to wet tissue, antibacterial activity, biosafety, ease of use, and stable storage, make QAL a promising emergency hemostatic agent.

Recent advances on thermosensitive hydrogels-mediated precision therapy

Precision therapy has become the preferred choice attributed to the optimal drug concentration in target sites, increased therapeutic efficacy, and reduced adverse effects. Over the past few years, sprayable or injectable thermosensitive hydrogels have exhibited high therapeutic potential. These can be applied as cell-growing scaffolds or drug-releasing reservoirs by simply mixing in a free-flowing sol phase at room temperature. Inspired by their unique properties, thermosensitive hydrogels have been widely applied as drug delivery and treatment platforms for precision medicine. In this review, the state-of-the-art developments in thermosensitive hydrogels for precision therapy are investigated, which covers from the thermo-gelling mechanisms and main components to biomedical applications, including wound healing, anti-tumor activity, osteogenesis, and periodontal, sinonasal and ophthalmic diseases. The most promising applications and trends of thermosensitive hydrogels for precision therapy are also discussed in light of their unique features.

Functional hemostatic hydrogels: design based on procoagulant principles

Uncontrolled hemorrhage results in various complications and is currently the leading cause of death in the general population. Traditional hemostatic methods have drawbacks that may lead to ineffective hemostasis and even the risk of secondary injury. Therefore, there is an urgent need for more effective hemostatic techniques. Polymeric hemostatic materials, particularly hydrogels, are ideal due to their biocompatibility, flexibility, absorption, and versatility. Functional hemostatic hydrogels can enhance hemostasis by creating physical circumstances conducive to hemostasis or by directly interfering with the physiological processes of hemostasis. The procoagulant principles include increasing the concentration of localized hemostatic substances or establishing a physical barrier at the physical level and intervention in blood cells or the coagulation cascade at the physiological level. Moreover, synergistic hemostasis can combine these functions. However, some hydrogels are ineffective in promoting hemostasis or have a limited application scope. These defects have impeded the advancement of hemostatic hydrogels. To provide inspiration and resources for new designs, this review provides an overview of the procoagulant principles of hemostatic hydrogels. We also discuss the challenges in developing effective hemostatic hydrogels and provide viewpoints.

An All-In-One Transient Theranostic Platform for Intelligent Management of Hemorrhage

Developing theranostic devices to detect bleeding and effectively control hemorrhage in the prehospital setting is an unmet medical need. Herein, an all-in-one theranostic platform is presented, which is constructed by sandwiching silk fibroin (SF) between two silver nanowire (AgNW) based conductive electrodes to non-enzymatically diagnose local bleeding and stop the hemorrhage at the wound site. Taking advantage of the hemostatic property of natural SF, the device is composed of a shape-memory SF sponge, facilitating blood clotting, with ≈82% reduction in hemostatic time in vitro as compared with untreated blood. Furthermore, this sandwiched platform serves as a capacitive sensor that can detect bleeding and differentiate between blood and other body fluids (i.e., serum and water) via capacitance change. In addition, the AgNW electrode endows anti-infection efficiency against Escherichia coli and Staphylococcus aureus. Also, the device shows excellent biocompatibility and gradually biodegrades in vivo with no major local or systemic inflammatory responses. More importantly, the theranostic platform presents considerable hemostatic efficacy comparable with a commercial hemostat, Dengen, in rat liver bleeding models. The theranostic platform provides an unexplored strategy for the intelligent management of hemorrhage, with the potential to significantly improve patients' well-being through the integration of diagnostic and therapeutic capabilities.

Biomimetic and Multifunctional Hemostatic Hydrogel with Rapid Thermoresponsive Gelation and Robust Wet Adhesion for Emergency Hemostasis: A Rational Design Based on Photo-Cross-Linking Coordinated Hydrophilic-Hydrophobic Balance Strategies

Uncontrolled bleeding in emergency situations is a great threat to both military and civilian lives, and an ideal hemostat for effectively controlling prehospital hemorrhage is urgently needed but still lacking. Although hemostatic hydrogels are promising for emergency hemostasis, they are currently challenged by either the mutual exclusion between a short gelation time and strong adhesive network or the insufficient functionality of ingredients and complicated operations for in situ curing. Herein, an extracellular matrix biopolymer-based and multifunctional hemostatic hydrogel that simultaneously integrates rapid thermoresponsive gelation, robust wet adhesion, and ease of use in emergencies is rationally engineered. This hydrogel can be conveniently used via simple injection and achieves instant sol-gel phase transition at body temperature. Its comprehensive performance could be facilely regulated by tuning the proportions of components, and the optimal performance (gelation time 6-8 s, adhesion strength 125 ± 3.6 kPa, burst pressure 282 ± 4.1 mmHg) is established due to the coordinated enhancement of the photo-cross-linking pretreatment and the hydrophilic-hydrophobic balance among various interactions in the hydrogel system. Additionally, it exhibits significant coagulation effect in vitro and enables effective hemostasis and wound healing in vivo. This work provides a promising platform for versatile applications of hydrogel-based materials, including emergency hemostasis.