Robust and Wet Adhesive Self-Gelling Powders for Rapid Hemostasis and Efficient Wound Healing

A Polysaccharide-Based Self-Gelling Powder With Antibacterial and Antioxidant Capacities for Acute Hemostasis and Efficient Infected Wound Healing

Traumatic wounds with severe bleeding and heavy contamination present significant challenges, including delayed healing and high infection rates. An ideal wound dressing should achieve rapid hemostasis, provide antibacterial activity, and regulate the microenvironment to facilitate tissue regeneration. To address these needs, this work develops a novel selfgelling powder (COT) comprising carboxymethyl chitosan (CMCS), oxidized konjac glucomannan (OKGM), and tannic acid (TA). The COT powder exhibits rapid gelation upon contact with water, forming a COT hydrogel, making it suitable for controlling hemorrhage across diverse wound sites. In vitro and in vivo studies confirm that the COT possesses broad-spectrum antibacterial activity and potent free radical scavenging capacity. When applied to infected wounds, the COT hydrogel significantly reduces oxidative stress and inflammatory responses while promoting angiogenesis and re-epithelialization. Transcriptomic analysis suggests that COT modulates wound inflammation, likely by suppressing the NF-κB signaling pathway. Given its favorable mechanical properties, strong antibacterial/antioxidant effects, ease of application, and rapid hemostatic performance, the COT emerges as a promising translational wound dressing for managing infected wounds.

Green and Efficient Preparation of Chitosan-Based Sponge with In Situ Synthesized ZnO for Deep Trauma Bleeding and Wound Healing

Deep trauma often leads to acute bleeding and infections, which are major causes of death. It is worth exploring the preparation of hemostatic materials and improving their hemostatic and antibacterial properties applied to deep trauma by green and efficient methods. In this study, porous chitosan/zinc oxide/alkylated chitosan (CS/ZnO/ACS) sponges were prepared by a freezing phase separation method. ACS induced the formation of stable foam, increasing the pore formation during the freezing phase separation process. The porous structure enabled the sponge to rapidly absorb blood and expand to close the wound. The in situ synthesis of ZnO within the sponge enhances its antibacterial properties. In the antibacterial test against S. aureus and E. coli, the CS/ZnO/ACS sponges can effectively inhibit bacterial growth. Besides, compared with CS sponges, the introduction of ACS increases the adhesion of the CS/ZnO/ACS sponges to blood cells and promotes coagulation. In addition, the CS/ZnO/ACS sponges were prepared by physical phase separation, which endows it with increased solubility under acidic conditions and can be quickly removed after hemostasis. Therefore, the CS/ZnO/ACS expandable sponges offer promising clinical applications for the treatment of deep trauma.

A thermosensitive poloxamer hydrogel with ofloxacin and cationic microparticles for antibacterial and hemostatic applications

Traditional hemostatic materials often fall short of meeting clinical demands in terms of both hemostasis and antibacterial efficiency. The use of cationic materials in the antibacterial and hemostatic fields has garnered significant attention. However, designing materials that effectively balance these two properties remains a critical challenge in the development of hemostatic materials. In this context, a dual-functional hydrogel (F-QMS-OX) was developed by incorporating cationic starch microparticles (QMS) and ofloxacin into a thermosensitive poloxamer hydrogel with optimized loading content. After verifying the synergistic antibacterial effect of QMS and ofloxacin, in vitro experiments demonstrated that the concentration of ofloxacin within the hydrogel played a crucial role in determining its hemostatic and antibacterial properties. Among the tested formulations, the F-QMS-OX1 hydrogel, which contained the optimal (lowest) ofloxacin loading, achieved an exceptional balance between hemostasis and antibacterial activity. The underlying mechanism was identified as the regulation of blood cell/protein-hydrogel (surface) interactions for accelerating hemostasis. Furthermore, the F-QMS-OX1 hydrogel exhibited superior hemostatic performance in a femoral-artery-injury model and on-demand removal of hydrogel from wounds due to its thermo-responsive properties. The developed dual-functional hydrogel holds significant promise for future medical applications in clinical hemostasis and anti-infection wound care.

An Antibacterial, Antioxidant Adherent Sponge Constructed for Control of Arterial Bleeding Via Gallic Acid-Mediated Robust Assembly of Fibrous Clay in Collagen

Acute hemorrhage death on battlefields, during clinical surgeries, and in major accidents is a widespread worldwide problem. Clay-based hemostatic materials have received considerable attention for their low cost and reliable clotting activity, especially in cases of severe bleeding, such as QuikClot, which is a kaolin-based hemostatic gauze that is preferred for battlefield resuscitation. However, the easy detachment of clay particles and the associated risk of thrombosis have seriously hindered the development of clay-based hemostatic materials. Here, inexpensive palygorskite (Pal) nanoclay was integrated into the collagen (COL) matrix by loading Ca2+ in the clay and further using gallic acid (GA) to mediate the robust assembly of clay on the COL matrix. This targeted interfacial design is a simple and gentle method that effectively improves the dispersion of the Pal particles and reduces the risk of shedding. Unlike QuikClot where the aqueous solution was significantly turbid after 2 min of ultrasonic washing, the aqueous solution of the composite sponge (Ca-Pal-GA-COL) remained clear and was accompanied by 82.71% of the mass residue after 10 min of ultrasonic washing. The composite sponge also exhibited excellent antibacterial (87.93% inhibition rate of Escherichia coli), antioxidant, and tissue adhesion properties. Importantly, the Ca-Pal-GA-COL sponge exhibited less blood loss (632 mg) and a shorter hemostasis time (151 s) in a rat femoral artery hemorrhage model than the medical gauze (3850 mg and 299 s), pure COL sponge (1627 mg and 201 s), and Pal-COL sponge (1494 mg and 193 s) in a co-mingled mode, which are comparable to those of QuikClot (559 mg and 142 s). Furthermore, certain tissue adhesion properties render the Ca-Pal-GA-COL sponge more suitable than QuikClot for severe femoral artery active bleeding scenarios. Cellular experiments confirmed that the composite dressing has a certain biosafety.

Oxidized hyaluronic acid/ε-polylysine/quaternized chitosan hydrogel with shear thinning injectability and self-healing properties for full-time and multipurpose wound healing

Complex wound closure scenarios necessitate the development of advanced wound dressings that can effectively address the challenges of filling irregularly shaped wounds and managing fatigue failures encountered in daily patient activities. To tackle these issues, we develop a multifunctional hydrogel from natural polysaccharides and polypeptides with injectability and self-healing properties for promoting full-time and multipurpose wound healing. Synthesized through dynamic Schiff base linkages between oxidized hyaluronic acid (OHA), ε-polylysine (ε-PL), and quaternized chitosan (QCS), the OHA/ε-PL/QCS hydrogel can gel rapidly within 50 s. It exhibits notable strong shear-thinning and self-healing behavior, allowing easy injection to fit various wound shapes while maintaining integrity. In rat models of liver and femoral artery injuries, the hydrogel shows significantly reduced bleeding and accelerated hemostasis. The hydrogel can enhance cell proliferation through cell migration and tube formation, stimulate angiogenesis, support collagen deposition, and reduce inflammation. Its superior biocompatibility also supports the safe encapsulation of epidermal growth factor (EGF). In infected full-thickness skin wound models, the OHA/ε-PL/QCS/EGF hydrogel achieves nearly complete wound closure within 10 days. Overall, this study highlights the outstanding therapeutic potentials of the injectable and self-healing OHA/ε-PL/QCS hydrogel as a promising solution for fulfilling the multi-purpose, sophisticated needs in complicated wound closure scenarios.

Rapid Fluid-Induced-Expanding Chitosan-Derived Hemostatic Sponges with Excellent Antimicrobial and Antioxidant Properties for Incompressible Hemorrhage and Wound Healing

Chitosan-based materials are known for their excellent biocompatibility and inherent hemostatic properties. However, their hemostatic efficiency is significantly affected by poor wettability and mechanical strength. Herein, we developed a novel hemostatic super elastic sponge from mussel-inspired chitosan modified with long alkyl and catechol functional groups (HMCC) via a simple freezing-drying procedure. The incorporation of decanal and catechol in the HMCC sponge significantly enhances its antimicrobial and antioxidant properties and facilitates multiple interactions with blood cells, thus promoting their enrichment for rapid hemostasis. Moreover, HMCC sponges exhibit high compressibility and rapid fluid-induced size recovery capacity, enabling wound shape adaptation to ensure minimizing irritation. In vivo experiments revealed that HMCC sponges possessed enhanced procoagulant, hemostasis abilities, and favorable degradability and could promote wound healing in a rat skin wound model. These results highlight the potential of the HMCC sponge as a promising solution for the clinical management of major bleeding.

A Self-Gelling Powder Based on Polyacrylic Acid/Polyethyleneimine/Polyethylene Glycol for High-Performance Hemostasis and Antibacterial Activity

Powder-based hemostatic materials have offered unprecedented opportunities for the effective sealing and repair of irregularly shaped wounds and high-pressure, noncompressible arterial bleeding wounds caused by surgeries, traffic accidents, and wartime injuries. However, inadequate adhesion to bleeding wounds and poor hemostasis in biological tissues remains challenging. Herein, we report a self-gelling hemostatic powder based on polyacrylic acid/polyethyleneimine/polyethylene glycol (named PPG) for rapid hemostasis and effective antibacterial ability. When deposited on bleeding wounds, PPG powder can absorb interfacial liquid and rapidly swell into a physically cross-linked hydrogel in situ within 2 s to form a pressure-resistant physical barrier. Furthermore, the in vivo and in vitro results indicate that, as an effective sealant, the PPG powder possesses ease of use, excellent hemocompatibility, strong antibacterial abilities, and superior blood clotting abilities. The effective hemostatic sealing capability of the PPG powder is demonstrated in a variety of injury models in rats and rabbits. All of these factors show that, with its superior wound treatment abilities, PPG powder is a profound biomaterial for surgical applications.

Epidermal growth factor-incorporated hydrogen bond crosslinked hemostatic microparticles capable of timely response to accidental bleeding for prehospital rescue

Prehospital rescue of accidental massive bleeding is crucial for saving lives. However, currently available hemostatic materials are still in infancy in treating accidental bleeding due to the challenges in fully satisfying the complex outdoor hemostatic requirements. Herein, we designed an epidermal growth factor (EGF)- incorporated, microparticle-formed, high-strength, dynamic environment-stable hemostatic gel system for prehospital rescue. Carboxyl and dimethylamide were employed as the hydrogen bond (H-bond) groups and were carefully engineered into the microparticles (DHMs). We demonstrated that the unique H-bond crosslinked micronized structure enabled the DHM-based gelling system to adequately meet the outdoor hemostatic requirements. The stable H-bond groups allow the DHMs to be stored at room temperature and be easily carried around. The small sizes (150-250 μm) of the DHMs enabled the filling of irregular defects, and upon encountering water, these DHMs integrated into hydrogels (DHMs-gels) with high mechanical strength (1.61 MPa), strong tissue adhesiveness (66.5 kPa) and stable performance under dynamic environments. In vivo results showed that the EGF-incorporated DHMs-gels (DHMs-EGF gel) achieved a 100 % survival rate in a simulated rescue process and promoted wound healing. Simultaneously possessing multiple prehospital rescue-required properties, the hemostatic DHMs-EGF may become an effective tool for emergency rescue.

AESIS-1, a Rheumatoid Arthritis Therapeutic Peptide, Accelerates Wound Healing by Promoting Fibroblast Migration in a CXCR2-Dependent Manner

In patients with autoimmune disorders such as rheumatoid arthritis (RA), delayed wound healing is often observed. Timely and effective wound healing is a crucial determinant of a patient's quality of life, and novel materials for skin wound repair, such as bioactive peptides, are continuously being studied and developed. One such bioactive peptide, AESIS-1, has been studied for its well-established anti-rheumatoid arthritis properties. In this study, we attempted to use the anti-RA material AESIS-1 as a therapeutic wound-healing agent based on disease-modifying antirheumatic drugs (DMARDs), which can help restore prompt wound healing. The efficacy of AESIS-1 in wound healing was assessed using a full-thickness excision model in diabetic mice; this is a well-established model for studying chronic wound repair. Initial observations revealed that mice treated with AESIS-1 exhibited significantly advanced wound repair compared with the control group. In vitro studies revealed that AESIS-1 increased the migration activity of human dermal fibroblasts (HDFs) without affecting proliferative activity. Moreover, increased HDF cell migration is mediated by upregulating chemokine receptor expression, such as that of CXC chemokine receptor 2 (CXCR2). The upregulation of CXCR2 through AESIS-1 treatment enhanced the chemotactic reactivity to CXCR2 ligands, including CXC motif ligand 8 (CXCL8). AESIS-1 directly activates the ERK and p38 mitogen-activated protein kinase (MAPK) signaling cascades, which regulate the migration and expression of CXCR2 in fibroblasts. Our results suggest that the AESIS-1 peptide is a strong wound-healing substance that increases the movement of fibroblasts and the expression of CXCR2 by turning on the ERK and p38 MAPK signaling cascades.