Advances in haemostatic sponges: Characteristics and the underlying mechanisms for rapid haemostasis

Smart design in biopolymer-based hemostatic sponges: From hemostasis to multiple functions

Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care, posing a major threat to human life. To achieve effective bleeding control, many hemostatic materials have emerged. Among them, nature-derived biopolymers occupy an important position due to the excellent inherent biocompatibility, biodegradability and bioactivity. Additionally, sponges have been widely used in clinical and daily life because of their rapid blood absorption. Therefore, we provide the overview focusing on the latest advances and smart designs of biopolymer-based hemostatic sponge. Starting from the component, the applications of polysaccharide and polypeptide in hemostasis are systematically introduced, and the unique bioactivities such as antibacterial, antioxidant and immunomodulation are also concerned. From the perspective of sponge structure, different preparation processes can obtain unique physical properties and structures, which will affect the material properties such as hemostasis, antibacterial and tissue repair. Notably, as development frontier, the multi-functions of hemostatic materials is summarized, mainly including enhanced coagulation, antibacterial, avoiding tumor recurrence, promoting tissue repair, and hemorrhage monitoring. Finally, the challenges facing the development of biopolymer-based hemostatic sponges are emphasized, and future directions for in vivo biosafety, emerging materials, multiple application scenarios and translational research are proposed.

Self-expanding cellulose sponge with enhanced hemostatic ability by tannic acid/metal ion composite coating for highly effective hemostasis of difficult-to-control bleeding wounds

Refractory bleeding presents a critical, life-threatening challenge, and the goal of medical professionals and researchers has always been to achieve safe and effective hemostasis for bleeding wounds. In this study, we utilized the benefits of a self-expanding cellulose sponge to control incompressible bleeding, which is achieved this by creating a tannic acid/metal ion coating on the surface and within the pores of the sponge to improve its hemostatic effectiveness. The effects of various types and concentrations of metal ions (calcium, magnesium, iron, and zinc) on hemostatic efficiency and biosafety is systematically investigated. The results from bacteriostasis and in vitro coagulation experiments identified 0.3 wt% Fe3+ as the optimal metal ion coating. Scanning electron microscope energy spectrum analysis confirmed the uniform distribution of Fe3+ within the cellulose sponge. Furthermore, the in vivo and in vitro results demonstrated that the prepared tannic acid/Fe3+ coated composite hemostatic sponge exhibits excellent coagulation ability and biocompatibility. Both the bleeding time and theblood loss in two bleeding models are significantly reduced, showing promising potential for treating extensive surface bleeding and deep penetrating wounds. Furthermore, the straightforward preparation method for this composite hemostatic sponge facilitates additional research towards market application.

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.

Rapid preparation of bioadhesive hydrogels containing catechol moieties at room temperature with reproducible adhesion to wet tissues, antimicrobial, antioxidant capacity for noncompressive hemostasis

In order to cope with the massive tissue bleeding caused by sudden trauma and the demand for bioengineering materials with adjustable wet adhesion properties, this study formed the first layer of network by adding galactomannan (GG) and collagen (Col) structure, and then use the Fe3+-urushiol (UH) redox system to activate free radicals to initiate the polymerization of acrylic acid (AA) to quickly form an interpenetrating double network hydrogel. The cis hydroxyl group in GG and the hydroxyl group of UH form dynamic covalent borate ester bonds with borate ions in the borax solution, and use their responsiveness to pH to control the catechol group to achieve controllable adhesion. UH and Fe3+ endowed the hydrogel with excellent antibacterial ability, while adding Col enhanced the mechanical properties of the hydrogel. The elastic modulus and toughness increased from 4.32 kPa and 92.9 kJ/m3 to 18.90 kPa and 264.54 kJ/m3. In addition, due to the joint action of UH and Col, the hydrogel dressing can achieve rapid hemostasis within 20 s. In short, this hydrogel dressing has good biocompatibility, inherent antibacterial ability, adjustable moist tissue adhesion properties and rapid hemostatic ability, and is expected to become a candidate for wound hemostasis dressing.

Engineering collagen-based biomaterials for cardiovascular medicine

Cardiovascular diseases have been the leading cause of global mortality and disability. In addition to traditional drug and surgical treatment, more and more studies investigate tissue engineering therapeutic strategies in cardiovascular medicine. Collagen interweaves in the form of trimeric chains to form the physiological network framework of the extracellular matrix of cardiac and vascular cells, possessing excellent biological properties (such as low immunogenicity and good biocompatibility) and adjustable mechanical properties, which renders it a vital tissue engineering biomaterial for the treatment of cardiovascular diseases. In recent years, promising advances have been made in the application of collagen materials in blood vessel prostheses, injectable cardiac hydrogels, cardiac patches, and hemostatic materials, although their clinical translation still faces some obstacles. Thus, we reviewed these findings and systematically summarizes the application progress as well as problems of clinical translation of collagen biomaterials in the cardiovascular field. The present review contributes to a comprehensive understanding of the application of collagen biomaterials in cardiovascular medicine.

Graphical abstract

Developing a multifunctional chitosan composite sponge for managing traumatic injuries

Developing porous hemostatic sponges that are both biosafe and multifunctional remains a complex challenge. Conventional hemostatic techniques often fall short in managing bleeding effectively, leading to severe critical cases such as suboptimal hemostasis, increased infection risk, and complications arising from profuse bleeding. To address these deficits, our study introduces a novel multifunctional nanocomposite sponge that synergistically incorporates chitosan (CS), cellulose (Cel), graphene oxide (GO), and silver (Ag) nanoparticles. The resulting CS/Cel/GO/Ag developed demonstrates a swelling rate exceeding 3000 %, an absorption rate of over 2100 %, and the lowest stress surpassing 20 kPa at an initial 80 % strain. In vitro analyses reveal that the CS/Cel/GO/Ag sponge has excellent cytocompatibility, non-hemolytic nature, and competence in blood cell adherence and bacterial inhibition. In vivo evaluations further demonstrate that compared to conventional hemostatic methods, the sponge substantially enhances hemostatic efficacy, as evidenced by the marked reductions in clotting times and diminished blood loss compared to conventional hemostatic methods. Specifically, the test results of the CS/Cel/GO/Ag sponge across three different models are as follows: for the rat tail amputation model, the clotting time was 99 s, while blood loss was 222 mg; for the rat liver injury model, the clotting time was 129 s. while blood loss was 812 mg; for the rat femoral artery laceration model, the clotting time was 96 s, while blood loss was 758 mg. The compelling attributes of the CS/Cel/GO/Ag sponges position them as a promising solution for the acute management of bleeding. Their excellent performance indicates they have potential role to play in trauma care.

A randomized comparison of an adhesive gelatin sponge and a plain collagen sponge for hemostatic control during canine liver surgery

OBJECTIVE

To compare the effectiveness of a modified surface gelatin sponge to a plain collagen sponge for hemostasis of parenchymal hepatic bleeding.

STUDY DESIGN

Prospective, randomized trial of two hemostatic agents.

ANIMALS

A total of 45 dogs undergoing elective liver surgery were randomly allocated into two groups: 22 in the adhesive gelatin (AG) group and 23 in the plain collagen (PC) group. A total of 20 patients per group underwent liver biopsy to create a uniformly sized bleeding surface, with the remaining patients (AG = 2, PC = 3) undergoing liver lobectomy.

METHODS

Evaluation of hemostatic effectiveness and tissue adhesion of each sponge type was performed by the operating surgeon using structured scoring systems. Hemostatic parameters were primarily evaluated at the liver biopsy site to maintain homogeneity of bleeding surface size.

RESULTS

For the liver biopsy group (n = 40), 5 min after hemostatic sponge application, 10/20 dogs were bleeding in the PC group, compared to 2/20 in AG group (p = .0138). The PC bleeding was significantly higher than AG across the 3 to 6 min evaluation period (p < .001). When surgeons tested the adhesion of the sponge across the whole cohort (n = 45), AG scored 2 (of 3) against 1 for PC (p < .001). In group PC, 5/23 sponges dislodged during abdominal lavage and preparations for closure and had to be replaced due to recurrence of bleeding, compared with no AG sponges dislodging (p = .042). There were no further complications related to the use of either sponge.

CONCLUSION

In the dogs with hepatic parenchymal incision, use of an adhesive gelatin sponge improved intraoperative attachment and haemostatic effectiveness, compared to a collagen sponge.

CLINICAL SIGNIFICANCE

Based on our clinical experience in these cases, adhesive gelatin sponges could be considered an effective option when selecting a hemostatic agent for liver surgery in dogs.

Advancements in wound management: integrating nanotechnology and smart materials for enhanced therapeutic interventions

Wound management spans various techniques and materials tailored to address acute and chronic non-healing wounds, with the primary objective of achieving successful wound closure. Chronic wounds pose additional challenges, often necessitating dressings to prepare the wound bed for subsequent surgical procedures like skin grafting. Ideal dressing materials should not only expedite wound healing but also mitigate protein, electrolyte, and fluid loss while minimizing pain and infection risk. Nanotechnology has emerged as a transformative tool in wound care, revolutionizing the landscape of biomedical dressings. Its application offers remarkable efficacy in accelerating wound healing and combating bacterial infections, representing a significant advancement in wound care practices. Integration of nanotechnology into dressings has resulted in enhanced properties, including improved mechanical strength and controlled drug release, facilitating tailored therapeutic interventions. This review article comprehensively explores recent breakthroughs in wound healing therapies, with a focus on innovative medical dressings such as nano-enzymes. Additionally, the utilization of smart materials, like hydrogels and electroactive polymers, in wound dressings offers dynamic functionalities to promote tissue regeneration. Emerging concepts such as bio-fabrication, microfluidic systems, bio-responsive scaffolds, and personalized therapeutics show promise in expediting wound healing and minimizing scarring. Through an in-depth exploration of these advancements, this review aims to catalyze a paradigm shift in wound care strategies, promoting a patient-centric approach to therapeutic interventions.

Local and Systemic Hemostatic Agents: A Comprehensive Review

Traumatic hemorrhage is the leading preventable cause of death worldwide. Systemic administration of hemostatic agents requires trained personnel and preparation, limiting their use in combat environments and prehospital settings. However, local administration of hemostatic agents may ameliorate these challenges. Currently available hemostatic products are limited by risk of infection, immunogenicity, tissue damage, limited usage and efficacy, high costs, short shelf life, and storage requirements under specific conditions. Future studies should be considered to overcome these limitations and develop effective, multifunctional hemostatic materials for widespread usage. In this review, we will provide an overview of the most commonly used systemic and local hemostatic agents in hemorrhage control.

Superhydrophobic Cellulose Nanofiber Aerogels for Efficient Hemostasis with Minimal Blood Loss

Reducing unnecessary blood loss in hemostasis is a major challenge for traditional hemostatic materials due to uncontrolled blood absorption. Tuning the hydrophilic and hydrophobic properties of hemostatic materials provides a road to reduce blood loss. Here, we developed a superhydrophobic aerogel that enabled remarkably reduced blood loss. The aerogel was fabricated with polydopamine-coated and fluoroalkyl chain-modified bacterial cellulose via a directional freeze-drying method. Primarily, the hydrophobic feature prevented blood from uncontrolled absorption by the material and overflowing laterally. Additionally, the aerogel had a dense network of channels that allowed it to absorb water from blood due to the capillary effect, and fluoroalkyl chains trapped the blood cells entering the channels to form a compact barrier via hydrophobic interaction at the bottom of the aerogel, causing quick fibrin generation and blood coagulation. The animal experiments reveal that the aerogel reduced the hemostatic time by 68% and blood loss by 87 wt % compared with QuikClot combat gauze. The study demonstrates the superiority of superhydrophobic aerogels for hemostasis and provides new insights into the development of hemostatic materials.

A macromolecular cross-linked alginate aerogel with excellent concentrating effect for rapid hemostasis

Alginate-based materials present promising potential for emergency hemostasis due to their excellent properties, such as procoagulant capability, biocompatibility, low immunogenicity, and cost-effectiveness. However, the inherent deficiencies in water solubility and mechanical strength pose a threat to hemostatic efficiency. Here, we innovatively developed a macromolecular cross-linked alginate aerogel based on norbornene- and thiol-functionalized alginates through a combined thiol-ene cross-linking/freeze-drying process. The resulting aerogel features an interconnected macroporous structure with remarkable water-uptake capacity (approximately 9000 % in weight ratio), contributing to efficient blood absorption, while the enhanced mechanical strength of the aerogel ensures stability and durability during the hemostatic process. Comprehensive hemostasis-relevant assays demonstrated that the aerogel possessed outstanding coagulation capability, which is attributed to the synergistic impacts on concentrating effect, platelet enrichment, and intrinsic coagulation pathway. Upon application to in vivo uncontrolled hemorrhage models of tail amputation and hepatic injury, the aerogel demonstrated significantly superior performance compared to commercial alginate hemostatic agent, yielding reductions in clotting time and blood loss of up to 80 % and 85 %, respectively. Collectively, our work illustrated that the alginate porous aerogel overcomes the deficiencies of alginate materials while exhibiting exceptional performance in hemorrhage, rendering it an appealing candidate for rapid hemostasis.

3D Printing of Naturally Derived Adhesive Hemostatic Sponge

Hydrogel hemostatic sponges have been recognized for its effectiveness in wound treatment due to its excellent biocompatibility, degradability, as well as multi-facet functionalities. Current research focuses on optimizing the composition and structure of the sponge to enhance its therapeutic effectiveness. Here, we propose an adhesive hydrogel made from purely natural substances extracted from okra and Panax notoginseng. We utilize 3-dimensional (3D) printing technology to fabricate the hemostatic hydrogel scaffold, incorporating gelatin into the hydrogel and refining the mixing ratio. The interaction between gelatin and okra polyphenols contributes to successful injectability as well as stability of the printed scaffold. The okra in the scaffold exhibits favorable adhesion and hemostatic effects, and the total saponins of Panax notoginseng facilitate angiogenesis. Through in vitro experiments, we have substantiated the scaffold's excellent stability, adhesion, biocompatibility, and angiogenesis-promoting ability. Furthermore, in vivo experiments have demonstrated its dual functionality in rapid hemostasis and wound repair. These features suggest that the 3D-printed, natural substance-derived hydrogel scaffolds have valuable potential in wound healing and related applications.

Antibacterial sponge for rapid noncompressible hemostatic treatment: spatiotemporal studies using a noninvasive model

Hemorrhage is one of the leading causes of preventable death. While minor injuries can be treated mainly by conventional methods, deep and irregular wounds with profuse bleeding present significant challenges, some of which can be life-threatening and fatal. This underscores the need to develop easily applicable FDA-approved hemostatic treatments that can effectively stanch blood loss at the point of care before professional medical care. A silicone-based bandage system (SilFoam), a non-compressible, self-expanding, antibacterial hemostatic treatment, is reported here. Its two-component system reacts in situ upon mixing to form a stretchable sponge that acts as a 'tamponade' by expanding within seconds with the evolution of oxygen gas from the interaction of the reactive components present in the formulation. This generates autogenous pressure on the wound that can effectively arrest heavy bleeding within minutes. Possessing optimal adhesive properties, the expanded sponge can be easily removed, rendering it optimal for hemostatic wound dressing. With recent advances in biotechnological research, there is a growing awareness of the potential issues associated with in vivo trials, spanning ethical, psychological, economic, and physiological concerns like burnout and fatigue. Bearing this in mind, a unique manikin system simulating a deep abdominal wound has been employed to investigate SilFoam's hemostatic efficacy with different blood-flow rates using a non-invasive model that aims to provide an easy, fast, and economical route to test hemostatic treatments before in vivo studies. This is the first time an Ag2O-based oxygen-induced foaming system has been reported as a hemostatic agent.

Additive-free Absorbable Keratin Sponge With Procoagulant Activity for Noncompressible Hemostasis

The development of a natural, additive-free, absorbable sponge with procoagulant activity for noncompressible hemostasis remains a challenging task. In this study, we extracted high molecular weight keratin (HK) from human hair and transformed it into a hemostatic sponge with a well-interconnected pore structure using a foaming technique, freeze-drying, and oxidation cross-linking. By controlling the cross-linking degree, the resulting sponge demonstrated excellent liquid absorption ability, shape recovery characteristics, and robust mechanical properties. The HK10 sponge exhibited rapid liquid absorption, expanding up to 600% within 5 s. Moreover, the HK sponge showed superior platelet activation and blood cell adhesion capabilities. In SD rat liver defect models, the sponges demonstrated excellent hemostatic performance by sealing the wound and expediting coagulation, reducing the hemostatic time from 825 to 297 s. Furthermore, HK sponges have excellent biosafety, positioning them as a promising absorbable sponge with the potential for the treatment of noncompressible hemostasis.

Cryogel wound dressings based on natural polysaccharides perfectly adhere to irregular wounds for rapid haemostasis and easy disassembly

Skin injuries can have unexpected surfaces, leading to uneven wound surfaces and inadequate dressing contact with these irregular surfaces. This can decrease the dressing's haemostatic action and increase the healing period. This study recommends the use of sticky and flexible cryogel coverings to promote faster haemostasis and efficiently handle uneven skin wounds. Alginate cryogels have a fast haemostatic effect and shape flexibility due to their macroporous structure. The material demonstrates potent antibacterial characteristics and enhances skin adherence by adding grafted chitosan with gallic acid. In irregular defect wound models, cryogels can cling closely to uneven damage surfaces due to their amorphous nature. Furthermore, their macroporous structure allows for quick haemostasis by quickly absorbing blood and wound exudate. After giving the dressing a thorough rinse, its adhesive strength reduces and it is simple to remove without causing any damage to the wound. Cryogel demonstrated faster haemostasis than gauze in a wound model on a rat tail, indicating that it has considerable potential for use as a wound dressing in the biomedical area.

Enhancing Wound Recovery: A Self-Gelling Powder for Improved Hemostasis and Healing

A novel self-gelatinizing powder was designed to accelerate wound healing through enhanced hemostasis and tissue recovery. Significantly, this research addresses the critical need for innovative wound management solutions by presenting a novel approach. Carboxymethylcellulose calcium (CMC-Ca) was synthesized using an ion exchange method, and lysine (Lys) was integrated through physical mixing to augment the material's functional characteristics. The prepared powder underwent comprehensive evaluation for its self-gelling capacity, gelation time, adhesion, swelling rate, coagulation efficiency, hemostatic effectiveness, and wound healing promotion. Results indicate that the self-gelatinizing powder exhibited remarkable water absorption capabilities, absorbing liquid up to 30 times its weight and achieving rapid coagulation within 3 min. The inclusion of Lys notably enhanced the powder's gel-forming properties. The gelation time was determined to be within 4 s using a rotational rheometer, with the powder rapidly forming a stable gel on the skin surface. Furthermore, in a mouse skin injury model, near-complete skin recovery was observed within 14 days, underscoring the powder's impressive self-healing attributes and promising application prospects in wound management.

A 3D-Printed Cuttlefish Bone Elastomeric Sponge Rapidly Controlling Noncompressible Hemorrhage

Developing a self-expanding hemostatic sponge with high blood absorption and rapid shape recovery for noncompressible hemorrhage remains a challenge. In this study, a 3D-printed cuttlefish bone elastomeric sponge (CBES) is fabricated, which combined ordered channels and porous structures, presented tunable mechanical strength, and shape memory potentials. The incorporation of cuttlefish bone powder (CBp) plays key roles in concentrating blood components, promoting aggregation of red blood cells and platelets, and activating platelets, which makes CBES show enhanced hemostatic performance compared with commercial gelatin sponges in vivo. Moreover, CBES promotes more histiocytic infiltration and neovascularization in the early stage of degradation than gelatin sponges, which is conducive to the regeneration and repair of injured tissue. To conclude, CBp loaded 3D-printed elastomeric sponges can promote coagulation, present the potential to guide tissue healing, and broaden the hemostatic application of traditional Chinese medicine.

Kaolin loaded gelatin sponges for rapid and effective hemostasis and accelerated wound healing

Severe trauma with massive active blood loss, including liver and spleen rupture, arterial bleeding and pelvic fracture, will lead disability, malformation and even death. Therefore, it is very important to develop new, fast and efficient hemostatic materials. In this study, a novel Gelatin/Kaolin (GE/KA) composite sponge was developed. Meanwhile, to further investigate the effect of kaolin content on sponge properties, we prepared four types of sponges: GE/5% KA, GE/10% KA, GE/15% KA and GE/20% KA. The results of coagulation test in vitro showed that compared to the other groups, there were more activated adhered platelets and red blood cells on the surface of GE/15% KA. The results of hemostasis test in vivo showed that compared to other experimental groups, the GE/15% KA group had significantly less hemostasis time (liver hemostasis model: 69.50 ± 2.81 s; femoral artery hemostasis model: 75.17 ± 3.06 s) and bleeding volume (liver hemostasis model: 219.02 ± 10.39 mg; femoral artery hemostasis model: 948.00 ± 50.69 mg), and was similar to the commercial hemostasis material group. Additionally, the material properties of the sponge were characterized and its biocompatibility was verified as well through cell experiments and in vivo embedding experiments. All these results indicate that the optimal content of kaolin is 15%, which provides a theoretical basis for subsequent research. All in all, the novel GE/KA composite sponge prepared in this study can be used as a multifunctional hemostatic wound dressing for the treatment of complex wounds under various trauma scenes.

Revolutionizing Wound Healing: Exploring Scarless Solutions through Drug Delivery Innovations

Human skin is the largest organ and outermost surface of the human body, and due to the continuous exposure to various challenges, it is prone to develop injuries, customarily known as wounds. Although various tissue engineering strategies and bioactive wound matrices have been employed to speed up wound healing, scarring remains a significant challenge. The wound environment is harsh due to the presence of degradative enzymes and elevated pH levels, and the physiological processes involved in tissue regeneration operate on distinct time scales. Therefore, there is a need for effective drug delivery systems (DDSs) to address these issues. The objective of this review is to provide a comprehensive exposition of the mechanisms underlying the skin healing process, the factors and materials used in engineering DDSs, and the different DDSs used in wound care. Furthermore, this investigation will delve into the examination of emergent technologies and potential avenues for enhancing the efficacy of wound care devices.

Nanoengineered Supramolecular Adhesive Sponge for Rapid Hemostasis and Abdominal Wall Wound Healing

Multifunctional dressing biomaterials that can promote tissue adhesion, hemostasis, and soft-tissue wound healing are of great clinical significance. Here, we report a nanocomposite supramolecular sponge constructed by an air-in-water emulsion template composed of methacrylated gelatin (GelMA), Laponite nanoclay, and branched supramolecular polymer (PAMU). The sponge has an interconnected macroporous structure and exhibits tunable mechanical properties with varying Laponite concentration. The nanoengineered sponge is endowed with tissue adhesion by intermolecular hydrogen bonds and ionic interactions contributed by the supramolecular polymer and the Laponite nanoclay. The biocompatible sponge facilitates cell proliferation and blood coagulation in both in vitro and in vivo experiments. In addition, the results of the rat external abdominal wall defect model show that the sponge can promote angiogenesis, collagen deposition, and granulation tissue formation to accelerate wound repair. These findings suggest that the unique air-in-water templated sponge is a promising candidate for applications in hemostasis and wound healing.

Unravelling Surface Modification Strategies for Preventing Medical Device-Induced Thrombosis

The use of biomaterials in implanted medical devices remains hampered by platelet adhesion and blood coagulation. Thrombus formation is a prevalent cause of failure of these blood-contacting devices. Although systemic anticoagulant can be used to support materials and devices with poor blood compatibility, its negative effects such as an increased chance of bleeding, make materials with superior hemocompatibility extremely attractive, especially for long-term applications. This review examines blood-surface interactions, the pathogenesis of clotting on blood-contacting medical devices, popular surface modification techniques, mechanisms of action of anticoagulant coatings, and discusses future directions in biomaterial research for preventing thrombosis. In addition, this paper comprehensively reviews several novel methods that either entirely prevent interaction between material surfaces and blood components or regulate the reaction of the coagulation cascade, thrombocytes, and leukocytes.

Platelet Rich Plasma Loaded Multifunctional Hydrogel Accelerates Diabetic Wound Healing via Regulating the Continuously Abnormal Microenvironments

Continuous oxidative stress and cellular dysfunction caused by hyperglycemia are distinguishing features of diabetic wounds. It has been a great challenge to develop a smart dressing that can accelerate diabetic wound healing through regulating abnormal microenvironments. In this study, a platelet rich plasma (PRP) loaded multifunctional hydrogel with reactive oxygen species (ROS) and glucose dual-responsive property is reported. It can be conveniently prepared with PRP, dopamine (DA) grafted alginate (Alg-DA), and 6-aminobenzo[c][1,2]oxaborol-1(3H)-ol (ABO) conjugated hyaluronic acid (HA-ABO) through ionic crosslinks, hydrogen-bond interactions, and boronate ester bonds. The hydrogel possesses injectability, moldability, tissue adhesion, self-healing, low hemolysis, and hemostasis performances. Its excellent antioxidant property can create a low oxidative stress microenvironment for other biological events. Under an oxidative stress and/or hyperglycemia state, the hydrogel can degrade at an accelerated rate to release a variety of cytokines derived from activated blood platelets. The result is a series of positive changes that are favorable for diabetic wound healing, including fast anti-inflammation, activated macrophage polarization toward M2 phenotype, promoted migration and proliferation of fibroblasts, as well as expedited angiogenesis. This work provides an efficient strategy for chronic diabetic wound management and offers an alternative for developing a new-type PRP-based bioactive wound dressing.

Rational Design of Bioactive Materials for Bone Hemostasis and Defect Repair

Everyday unnatural events such as trauma, accidents, military conflict, disasters, and even medical malpractice create open wounds and massive blood loss, which can be life-threatening. Fractures and large bone defects are among the most common types of injuries. Traditional treatment methods usually involve rapid hemostasis and wound closure, which are convenient and fast but may result in various complications such as nerve injury, deep infection, vascular injury, and deep hematomas. To address these complications, various studies have been conducted on new materials that can be degraded in the body and reduce inflammation and abscesses in the surgical area. This review presents the latest research progress in biomaterials for bone hemostasis and repair. The mechanisms of bone hemostasis and bone healing are first introduced and then principles for rational design of biomaterials are summarized. After providing representative examples of hemostatic biomaterials for bone repair, future challenges and opportunities in the field are proposed.

Nanofiber Scaffolds as Drug Delivery Systems Promoting Wound Healing

Nanofiber scaffolds have emerged as a revolutionary drug delivery platform for promoting wound healing, due to their unique properties, including high surface area, interconnected porosity, excellent breathability, and moisture absorption, as well as their spatial structure which mimics the extracellular matrix. However, the use of nanofibers to achieve controlled drug loading and release still presents many challenges, with ongoing research still exploring how to load drugs onto nanofiber scaffolds without loss of activity and how to control their release in a specific spatiotemporal manner. This comprehensive study systematically reviews the applications and recent advances related to drug-laden nanofiber scaffolds for skin-wound management. First, we introduce commonly used methods for nanofiber preparation, including electrostatic spinning, sol-gel, molecular self-assembly, thermally induced phase separation, and 3D-printing techniques. Next, we summarize the polymers used in the preparation of nanofibers and drug delivery methods utilizing nanofiber scaffolds. We then review the application of drug-loaded nanofiber scaffolds for wound healing, considering the different stages of wound healing in which the drug acts. Finally, we briefly describe stimulus-responsive drug delivery schemes for nanofiber scaffolds, as well as other exciting drug delivery systems.