Armoring a liposome-integrated tissue factor with sacrificial CaCO3 to form potent self-propelled hemostats

Durable and biocompatible low adhesion wound dressing material based on interfacial behaviors for wound management

Wound-dressing adhesion is a problem that has not been effectively addressed in the field of wound care for bleeding or burn wounds. Design of low adhesion wound dressing materials by leveraging interfacial behaviors has been an effective solution to this problem. However, previously reported superhydrophobic low adhesion materials either had durability or biocompatibility issue. To bridge this gap, this study presents a durable and biocompatible superhydrophobic low adhesion wound dressing material, which is designed on a normal gauze substrate with biocompatible components using a hybrid coating strategy. Outstanding low adhesion properties have been verified in vivo with bleeding wound or burn wound, with a peeling force that is only 0.3 %-14.5 % of the conventional non-woven gauze. Prepared low adhesion materials can robustly retain their superhydrophobicity and blood-repelling properties against harsh tests. Moreover, their biocompatibility has been confirmed through a series of tests including cell biocompatibility, hemolysis and skin irritation tests. With these demonstrated merits, the durable and biocompatible low adhesion material developed in this study will provide an effective solution to the wound adhesion problem in the practice of wound management.

Nanofiber-based Multifunctional Microspheres for Rapid Hemostasis and Microorganism Removal of Water

Constructing hemostats capable of effectively controlling severe hemorrhage from irregular wounds presents significant challenges and imperatives. In this study, a novel approach is introduced using nanofibrous chitin microspheres (NCM) that are compressed to 60% strain (NCM-60%) to amplify their water-initiated expansion performance. This unique capacity allows NCM-60% to efficiently conform to and fill irregular bleeding cavities, even those of varying depths and curvatures, thereby promoting rapid blood coagulation at deep hemorrhage sites. NCM-60% exhibits effective control of severe femoral artery and "J"-shaped liver hemorrhages in 151 ± 6 s and 68 ± 15 s, respectively, revealing its exceptional hemostatic efficacy. Furthermore, NCM-60% exhibited promising capabilities in removing microbes from water, achieving removal rates of over 96% of bacteria. Blood compatibility assessments and cytotoxicity tests further confirmed the favorable biocompatibility of NCM-60%. Importantly, NCM-60% is found to biodegrade and be absorbed in vivo within 12 weeks. This study represents the first instance of leveraging chitin nanofiber-based biomaterials to design water-initiated expansion micro-hemostat, and integrate hemostatic functions with waterborne microorganism removal, thereby expanding the potential applications of micro-nanostructural materials in emergency first-aid scenarios.

A thermal cross-linking approach to developing a reinforced elastic chitosan cryogel for hemostatic management of heavy bleeding

Uncontrolled hemorrhage stands as the primary cause of potentially preventable deaths following traumatic injuries in both civilian and military populations. Addressing this critical medical need requires the development of a hemostatic material with rapid hemostatic performance and biosafety. This work describes the engineering of a chitosan-based cryogel construct using thermo-assisted cross-linking with α-ketoglutaric acid after freeze-drying. The resulting cryogel exhibited a highly interconnected macro-porous structure with low thermal conductivity, exceptional mechanical properties, and great fluid absorption capacity. Notably, assessments using rabbit whole blood in vitro, as well as rat liver volume defect and femoral artery injury models simulating severe bleeding, showed the remarkable hemostatic performance of the chitosan cryogel. Among the cryogel variants with different chitosan molecular weights, the 150 kDa one demonstrated superior hemostatic efficacy, reducing blood loss and hemostasis time by approximately 73 % and 63 % in the hepatic model, and by around 60 % and 68 %, in the femoral artery model. Additionally, comprehensive in vitro and in vivo evaluations underscored the good biocompatibility of the chitosan cryogel. Taken together, these results strongly indicate that the designed chitosan cryogel configuration holds significant potential as a safe and rapid hemostatic material for managing severe hemorrhage.

Chitosan thermogelation and cascade mineralization via sequential CaCO3 incorporations for wound care

Physically crosslinked hydrogels have shown great potential as excellent and eco-friendly matrices for wound management. Herein, we demonstrate the development of a thermosensitive chitosan hydrogel system using CaCO3 as a gelling agent, followed by CaCO3 mineralization to fine-tune its properties. The chitosan hydrogel effectively gelled at 37 °C and above after an incubation period of at least 2 h, facilitated by the CaCO3-mediated slow deprotonation of primary amine groups on chitosan polymers. Through synthesizing and characterizing various chitosan hydrogel compositions, we found that mineralization played a key role in enhancing the hydrogels' mechanical strength, viscosity, and thermal inertia. Moreover, thorough in vitro and in vivo assessments of the chitosan-based hydrogels, whether modified with mineralization or not, demonstrated their outstanding hemostatic activity (reducing coagulation time by >41 %), biocompatibility with minimal inflammation, and biodegradability. Importantly, in vivo evaluations using a rat burn wound model unveiled a clear wound healing promotion property of the chitosan hydrogels, and the mineralized form outperformed its precursor, with a reduction of >7 days in wound closure time. This study presents the first-time utilization of chitosan/CaCO3 as a thermogelation formulation, offering a promising prototype for a new family of thermosensitive hydrogels highly suited for wound care applications.

Development of alginate macroporous hydrogels using sacrificial CaCO3 particles for enhanced hemostasis

Polymeric hydrogels have increasingly garnered attention in the field of hemostasis. However, there remains a lack of targeted development and evaluation of non-dense polymeric hydrogels with physically incorporated pores to enhance hemostasis. Here, we present a facile route to macroporous alginate hydrogels using acid-induced CaCO3 dissolution to provide Ca2+ for alginate gelation and CO2 bubbles for subsequent macropore formation. The as-prepared pore structure in the hydrogels and its formation mechanisms were characterized through microscopic imaging and nitrogen adsorption/desorption tests. Functional analyses revealed that the macroporous hydrogels exhibited improved rheology, blood absorption, coagulation factor delivery, and platelet aggregation. Ultimately, the introduction of pores significantly enhanced the hemostatic effectiveness of alginate hydrogels in vivo, as demonstrated in rat tail amputation and liver injury models, leading to a reduction in blood loss of up to 77 % or a decrease in bleeding time of up to 88 %. Notably, hydrogels with higher porosity achieved with a CaCO3 to alginate ratio of 40 % outperformed those with lower porosity in the aforementioned properties. Furthermore, these improvements were found to be biocompatible and elicited minimal inflammation. Our findings underscore the potential of a simple porous hydrogel design to enhance hemostasis efficacy by physically incorporating macropores.

A peptide-engineered alginate aerogel with synergistic blood-absorbing and platelet-binding capabilities to rapidly stop bleeding

Polysaccharide matrix infused with hemostasis-stimulating chemistry represents a critical medical need of bleeding management. Herein, we describe the development of a polysaccharide-peptide conjugate platform, an alginate engineered with fibrinogen-derived platelet-binding peptides (APE). The alginate backbone was found to allow for multivalent grafting of the peptides. Processing APE conjugate into crosslinked aerogels promoted platelet accumulation, leading to a significant reduction in the coagulation time of whole rabbit blood and improving the stability of the formed clot. The APE aerogels also exhibited a high porosity and fluid uptake capacity (>90 in weight ratio) as well as good biocompatibility in hemostasis. Furthermore, in vivo studies conducted in rat models of tail cut and hepatic hemorrhage showed that APE aerogels reduced bleeding time by >58 % and blood loss by >61 %. The platelet-enrichment capacity of the APE construct synergized by high absorbency in its aerogel form offers a prototype for customized polysaccharide hemostats.

Trojan-horse mineralization of trigger factor to impregnate non-woven alginate fabrics for enhanced hemostatic efficacy

Uncontrolled hemorrhage remains a leading cause of mortality after trauma. This work describes a facile mineralization strategy for enhancing hemostatic efficacy of alginate non-woven fabrics, involving the precipitation of amorphous CaCO3 induced by alginate fibers, along with Trojan-horse-like tissue factor (TF) encapsulation. The amorphous CaCO3 served as a transient carrier, capable of releasing Ca2+ and TF upon contact with blood. Coagulation test and rat tail cut and hemorrhaging liver models all revealed superior hemostatic capability of mineralized TF-in-alginate fabrics compared to bare fabrics, solely mineralized form, or commercial zeolite-modified gauze, benefiting from the combined hemostatic properties of alginate matrix and released Ca2+ and TF. Meanwhile, comprehensive biocompatibility and mechanical stability evaluations demonstrate the ternary composite's good biosafety. These results along with the extension study with chitosan- and cellulose-based dressings underline the great potential and versatility of polysaccharide-hemostat-mediated CaCO3 mineralization with TF integration for achieving rapid hemorrhage control.