Influences of mesoporous zinc-calcium silicate on water absorption, degradability, antibacterial efficacy, hemostatic performances and cell viability to microporous starch based hemostat

Centrifugal Spinning-Derived Biomimetic Aerogel for Rapid Hemostasis with Minimal Blood Loss

For emergency treatment, especially in situations where rapid and effective hemostasis is required beyond the natural clotting mechanisms, advanced materials designed to reduce bleeding time and minimize blood loss have become an urgent need. Herein, a root hair-inspired aerogel is developed, which is characterized by a 99.99% interconnected pore structure and a three-dimensional network constructed by blocked aqueous isocyanates cross-linked grooved cellulose acetate and wrinkled thermoplastic polyurethane fibers via centrifugal spinning. The aerogel exhibits enhanced water absorption and minimal blood adsorption through rapid coagulation cascade activation. In vivo studies using rat tail, hepatic, and renal injury models demonstrate a substantial reduction in blood loss (∼94%) and hemostasis time (∼78%) compared to commercial hemostats. The developed aerogel offers a promising solution for urgent hemorrhage control.

Double Cross-linked Methacrylated Carboxymethyl Pea Starch Cryogels with Highly Compressive Elasticity and Hemostatic Function

As an abundant renewable natural material, starch has attracted unprecedented interest in the biomedical field. Carboxylated starch particles have been investigated for topical hemostasis, but the powder may not provide physical protection or support for wounds. Here, we prepared macroporous cryogel sponges of methacrylated carboxymethyl starch (CM-ST-MA) containing a covalent and a calcium ionic double network. The second ionic cross-linking network enhanced the compressive strength and toughness dramatically but reduced the swelling ratios. Cryogels and sponges exhibited excellent compressive elasticity at low Ca2+ concentrations (0.01 M). Cryogels became more plastic and dry sponges became rigid and brittle at high Ca2+ concentrations. The cryogels have outstanding wet-thermal stability but are still degradable via enzymatic hydrolysis. All CM-ST-MA sponges showed excellent biocompatibility, hemocompatibility, and outstanding hemostasis in in vitro assays. In the in vivo mouse tail amputation model, both CM-ST-MA cryogels without or with Ca2+ (0.01 M) reduced the blood loss and bleeding time significantly.

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.

Spatiotemporally Controlled Release of Etamsylate from Bioinspired Peptide-Functionalized Nanoparticles Arrests Bleeding Rapidly and Improves Clot Stability in a Rabbit Internal Hemorrhage Model

Achieving rapid clotting and clot stability are important unmet goals of clinical management of noncompressible hemorrhage. This study reports the development of a spatiotemporally controlled release system of an antihemorrhagic drug, etamsylate, in the management of internal hemorrhage. Gly-Arg-Gly-Asp-Ser (GRGDS) peptide-functionalized chitosan nanoparticles, with high affinity to bind with the GPIIa/IIIb receptor of activated platelets, were loaded with the drug etamsylate (etamsylate-loaded GRGDS peptide-functionalized chitosan nanoparticles; EGCSNP). Peptide conjugation was confirmed by LCMS, and the delivery system was characterized by DLS, SEM, XRD, and FTIR. In vitro study exhibited 90% drug release till 48 h fitting into the Weibull model. Plasma recalcification time and prothrombin time tests of GRGDS-functionalized nanoparticles proved that clot formation was 1.5 times faster than nonfunctionalized chitosan nanoparticles. The whole blood clotting time was increased by 2.5 times over clot formed under nonfunctionalized chitosan nanoparticles. Furthermore, the application of rheometric analysis revealed a 1.2 times stiffer clot over chitosan nanoparticles. In an in vivo liver laceration rabbit model, EGCSNP spatially localized at the internal injury site within 5 min of intravenous administration, and no rebleeding was recorded up to 3 h. The animals survived for 3 weeks after the injury, indicating the strong potential of the system for the management of noncompressible hemorrhage.

Chitosan/starch based unoxidized tannic acid modified microparticles for rapid hemostasis with broad spectrum antibacterial activity

The development of a rapid hemostat through a facile method with co-existing antibacterial activity and minimum erythrocyte lysis property stands as a major requirement in the field of hemostasis. Herein, a series of novel microparticle hemostats were synthesized using chitosan, different hydrothermally-treated starches, and cross-linked with tannic acid (TA) simultaneously in an unoxidized environment via ionotropic gelation method. Hemostats' comparative functional properties, such as adjustable antibacterial and erythrocyte compatibility upon various starch additions were evaluated. The in vivo hemostatic study revealed that the developed hemostats for mouse liver laceration and rat tail amputation had clotting times (13 s and 38 s, respectively) and blood loss (51 mg and 62 mg, respectively) similar to those of Celox™. The erythrocyte adhesion test suggested that erythrocyte distortion can be lowered by modifying the antibacterial hemostats with different starches. The broad-spectrum antibacterial efficacy of the hemostats remained intact against S. aureus (>90 %), E. coli (>80 %), and P. mirabilis bacteria upon starch modification. They also demonstrated high hemocompatibility (<3 % hemolysis ratio), moderate cell viability (>81 %), in vivo biodegradation, and angiogenesis indicating adequate biocompatibility and wound healing. The developed hemostats hold significant promise to be employed as rapid hemostatic agents for preventing major bleeding and bacterial infection in emergencies.

Tuning zinc content in wollastonite bioceramic endowing outstanding angiogenic and antibacterial functions beneficial for orbital reconstruction

Prosthetic eye is indispensable as filler after enucleation in patients with anophthalmia, whereas there are still many complications including postoperative infection and eye socket depression or extrusion during the conventional artificial eye material applications. Some Ca-silicate biomaterials showed superior bioactivity but their biological stability in vivo limit the biomedical application as long-term or permanent implants. Herein we aimed to understand the physicochemical and potential biological responses of zinc doping in wollastonite bioceramic used for orbital implants. The wollastonite powders with different zinc dopant contents (CSi-Znx) could be fabricated as porous implants with strut or curve surface pore geometries (cubic, IWP) via ceramic stereolithography. The experimental results indicated that, by increasing zinc-substituting-Ca ratio (up to 9%), the sintering and mechanical properties could be significantly enhanced, and meanwhile the bio-dissolution in vitro and biodegradability in vivo were thoroughly inhibited. In particular, an appreciable angiogenic activity and expected antibacterial efficacy (over 90 %) were synergistically achieved at 9 mol% Zn dopant. In the back-embedding and enucleation and implantation model experiments in rabbits, the superior continuous angiogenesis was corroborated from the 2D/3D fibrovascular reconstruction in the IWP-pore CSi-Zn9 and CSi-Zn13.5 groups within very short time stages. Totally, the present silicate-based bioceramic via selective Zn doping could produce outstanding structural stability and bifunctional biological responses which is especially valuable for developing the next-generation implants with vascular insertion and fixation in orbital reconstruction prothesis.

Effect of different drying methods on the structure and properties of porous starch

In order to investigate the effects of different drying methods on the properties of porous starch. The present study used four drying methods, namely hot air drying (HD), spray drying (SPD), vacuum freeze drying (FD) and supercritical carbon dioxide drying (SCD) to prepare maize and kudzu porous starch. Findings indicated that the physicochemical properties (e.g., morphology, crystallinity, enthalpy value, porosity, surface area and water absorption capacity as well as dye absorption capacity, particle size) of porous starch were significantly affected by the drying method. Compared with other samples, SCD-treated porous starch exhibited the highest surface areas of the starch (2.943 and 3.139 m2/g corresponding to kudzu and maize, respectively), amylose content (22.02 % and 16.85 % corresponding to kudzu and maize, respectively), MB and NR absorption capacity (90.63 %, 100.26 % and 90.63 %, 100.26 %, corresponding to kudzu ad maize, respectively), and thermal stability, whereas HD-treated porous starch showed the highest water-absorption capacity (123.8 % and 131.31 % corresponding to kudzu and maize, respectively). The dye absorption of the maize and kudzu porous starch was positively correlated with surface area, according to Pearson's correlation analysis. Therefore, in this study, our aim was to explore the effects of different drying methods on the Structure and properties of porous starch, and provide reference for selecting the best drying method for its application in different fields.

Development of an efficient hemostatic material based on cuttlefish ink nanoparticles loaded in cuttlebone biocomposite

Traumatic hemorrhage is one of the main causes of mortality in civilian and military accidents. This study aimed to evaluate the effectiveness of cuttlefish bone (cuttlebone, CB) and CB loaded with cuttlefish ink (CB-CFI) nanoparticles for hemorrhage control. CB and CB-CFI were prepared and characterized using different methods. The hemostasis behavior of constructed biocomposites was investigated in vitro and in vivo using a rat model. Results showed that CFI nanoparticles (NPs) are uniformly dispersed throughout the CB surface. CB-CFI10 (10 mg CFI in 1.0 g of CB) showed the best blood clotting performance in both in vitro and in vivo tests. In vitro findings revealed that the blood clotting time of CB, CFI, and CB-CFI10 was found to be 275.4 ± 12.4 s, 229.9 ± 19.9 s, and 144.0 ± 17.5 s, respectively. The bleeding time in rat liver injury treated with CB, CFI, and CB-CFI10 was 158.1 ± 9.2 s, 114.0 ± 5.7 s, and 46.8 ± 2.7 s, respectively. CB-CFI10 composite resulted in more reduction of aPTT (11.31 ± 1.51 s) in comparison with CB (17.34 ± 2.12 s) and CFI (16.79 ± 1.46 s) (p < 0.05). Furthermore, CB and CB-CFI10 exhibited excellent hemocompatibility. The CB and CB-CFI did not show any cytotoxicity on human foreskin fibroblast (HFF) cells. The CB-CFI has a negative surface charge and may activate coagulation factors through direct contact with their components, including CaCO3, chitin, and CFI-NPs with blood. Thus, the superior hemostatic potential, low cost, abundant, simple, and time-saving preparation process make CB-CFI a very favorable hemostatic material for traumatic bleeding control in clinical applications.

The characterization and analysis of the compound hemostatic cotton based on Ca2+/poly (vinyl alcohol)/soluble starch-fish skin collagen

Accidental bleeding is an unavoidable problem in daily life. To avoid the risk of excessive blood loss, it is urgent to design a functional material that can quickly stop bleeding. In this study, an efficient wound dressing for hemostasis was investigated. Based on the characteristics that Ca2+ and fish skin collagen (FSC) could activate the coagulation mechanism, hemostatic cotton was prepared by solvent replacement method using CaCl2, FSC, soluble starch (SS), and polyvinyl alcohol (PVA) as raw materials. The cytotoxicity test showed the Ca2+PVA/FSC-SS hemostatic cottons had good biocompatibility. The activated partial thromboplastin time (APTT) of Ca2+PVA/FSC-SS(4) was 35.34 s, which was 22.07 s faster than that of PVA/FSC-SS, indicating Ca2+PVA/FSC-SS mediated the endogenous coagulation system. In vitro coagulation test, Ca2+PVA/FSC-SS(4) could stop bleeding rapidly within 39.60 ± 5.16 s, and the ability of wound healing was higher than commercial product (Celox). This study developed a rapid procoagulant and hemostatic material, which had a promising application in a variety of environments.

Preparation and application of hemostatic microspheres containing biological macromolecules and others

Bleeding from uncontrollable wounds can be fatal, and the body's clotting mechanisms are unable to control bleeding in a timely and effective manner in emergencies such as battlefields and traffic accidents. For irregular and inaccessible wounds, hemostatic materials are needed to intervene to stop bleeding. Hemostatic microspheres are promising for hemostasis, as their unique structural features can promote coagulation. There is a wide choice of materials for the preparation of microspheres, and the modification of natural macromolecular materials such as chitosan to enhance the hemostatic properties and make up for the deficiencies of synthetic macromolecular materials makes the hemostatic microspheres multifunctional and expands the application fields of hemostatic microspheres. Here, we focus on the hemostatic mechanism of different materials and the preparation methods of microspheres, and introduce the modification methods, related properties and applications (in cancer therapy) for the structural characteristics of hemostatic microspheres. Finally, we discuss the future trends of hemostatic microspheres and research opportunities for developing the next generation of hemostatic microsphere materials.

Enhancement of hemostatic properties of Cyclotella cryptica frustule through genetic manipulation

BACKGROUND

The silicified cell wall of diatoms, also known as frustule, shows huge potential as an outstanding bio-nanomaterial for hemostatic applications due to its high hemostatic efficiency, good biocompatibility, and ready availability. As the architectural features of the frustule determine its hemostatic performance, it is of great interest to develop an effective method to modify the frustule morphology into desired patterns to further improve hemostatic efficiency.

RESULTS

In this study, the gene encoding Silicalemma Associated Protein 2 (a silicalemma-spanning protein) of Cyclotella cryptica (CcSAP2) was identified as a key gene in frustule morphogenesis. Thus, it was overexpressed and knocked down, respectively. The frustule of the overexpress lines showed no obvious alteration in morphology compared to the wild type (WT), while the size, specific surface area (BET), pore volume, and pore diameter of the knockdown strains changed greatly. Particularly, the knockdown frustules achieved a more pronounced coagulation effect and in vivo hemostatic performance than the WT strains. Such observations suggested that silicalemma proteins are ideal genetic encoding targets for manipulating frustule morphology associated hemostatic properties. Furthermore, the Mantel test was adopted to identify the key morphologies associated with C. cryptica bleeding control. Finally, based on our results and recent advances, the mechanism of frustule morphogenesis was discussed.

CONCLUSION

This study explores a new strategy for enhancing the hemostatic efficiency of the frustule based on genetic morphology modification and may provide insights into a better understanding of the frustule morphogenesis mechanism.

Recent advances of antibacterial starch-based materials

Starch has attracted a lot of attention because it is biodegradable, renewable, nontoxic and low cost. By adding antibacterial substances to starch, starch-based materials have antibacterial properties. The composite with other materials can improve the comprehensive performance of starch-based materials, thus broadening the application field of the material. In this paper, we focus on antibacterial starch-based materials and review their preparation and applications. It was found that antibacterial starch-based materials were most widely used in packaging, followed by medicine, and the research on smart starch-based materials was relatively less. This review may provide some reference value for subsequent studies of starch-based materials.

A self-gelling starch-based sponge for hemostasis

Uncontrolled bleeding remains one of the direct causes of high mortality. There is an urgent need for developing emergency hemostats capable of coping with uncontrolled bleeding. The commercial starch-based hemostatic powder (PerClot®) requires compression during application, which limits its application in hemostasis of irregular and non-compressed wounds. Herein, a boronic acid-modified thiol starch sponge (St-SP sponge) with self-gelling properties was developed for hemorrhage control. The results show that the St-SP sponge could quickly absorb blood, self-gel and self-heal to seal the bleeding sites. In addition, the St-SP sponge can rapidly initiate the coagulation cascade and promote the adhesion and aggregation of erythrocytes and platelets. The St-SP sponge exhibited significantly improved in vitro and in vivo hemostatic abilities as compared with PerClot. Notably, the St-SP sponge attained complete hemostasis without any compression in 61.5 s and made a great difference compared to PerClot (169 s) for the irregular wound constructed on the rabbit liver. In addition, the St-SP sponge had good hemocompatibility and cytocompatibility. It turns out that the newly developed St-SP sponge is a promising material for first-aid hemostasis of irregular and non-compressed wounds.

Novel resorbable bone wax containing β-TCP and starch microspheres for accelerating bone hemostasis and promoting regeneration

Traditional non-resorbable bone wax has been used in clinical surgery for more than 100 years. However, residual bone wax has been proven to cause numerous complications. In this study, a novel resorbable bone wax was designed to overcome the disadvantages of traditional non-resorbable bone wax. Alkylene oxide copolymers were used as the main component of resorbable bone wax; additionally, β-tricalcium phosphate and starch microspheres were added to enhance bone regeneration and hemostatic ability. This novel resorbable bone wax has a high potential for clinical translation and is expected to be developed as a substitute for traditional bone wax.

Trends of calcium silicate biomaterials in medical research and applications: A bibliometric analysis from 1990 to 2020

Background: Calcium silicate biomaterials (CSB) have witnessed rapid development in the past 30 years. This study aimed to accomplish a comprehensive bibliometric analysis of the published research literature on CSB for biomedical applications and explore the research hotspot and current status.

Methods: Articles related to CSB published in the last three decades (1990–2020) were retrieved from Web of Science Core Collection. The R bibliometrix package and VOSviewer were used to construct publication outputs and collaborative networking among authors, their institutes, countries, journals’ matrices and keywords plus.

Results: A total of 872 publications fulfilling the search criteria were included. CSB is mainly reported for bone tissues and dental applications. Among researchers, Chang J from Chinese Academy of Sciences and Gandolfi MG from the University of Bologna are the most productive author in these two fields, respectively. China was the leading contributor to the research on CSB in the medical field. A total of 130 keywords appeared more ten or more times were identified. The term “mineral trioxide aggregate” ranked first with 268 occurrences. The co-occurrence analysis identified three major clusters: CSB in dentistry, bone tissue and vitro bioactivity.

Conclusion: Calcium silicate biomaterials have a promising scope for various biomedical applications ranging from regeneration of hard tissues (bone and teeth) to skin, tumor, cardiac muscle and other soft tissues. This study may help researchers further understand the frontiers of the field.

Biological Application of Novel Biodegradable Cellulose Composite as a Hemostatic Material

Degradable hemostatic materials have unique advantages in reducing the amount of bleeding, shortening the surgical operation time, and improving patient prognosis. However, none of the current hemostatic materials are ideal and have disadvantages. Therefore, a novel biodegradable cellulose-based composite hemostatic material was prepared by crosslinking sodium carboxymethyl cellulose (CCNa) and hydroxyethyl cellulose (HEC), following an improved vacuum freeze-drying method. The resulting cellulose composite material was neutral in pH and spongy with a density of 0.042 g/cm³, a porosity of 77.68%, and an average pore size of 13.45 μm. The composite's compressive and tensile strengths were 0.1 MPa and 15.2 MPa, respectively. Under in vitro conditions, the composites were degraded gradually through petite molecule stripping and dissolution, reaching 96.8% after 14 days and 100% degradation rate at 21 days. When implanted into rats, the degradation rate of the composite was slightly faster, reaching 99.7% in 14 days and 100% in 21 days. Histology showed a stable inflammatory response and no evidence of cell degeneration, necrosis, or abnormal hyperplasia in the tissues around the embedded material, indicating good biocompatibility. In the hemorrhagic liver model, the time to hemostasis and the total blood loss in the cellulose composite group was significantly lower than in the medical gauze group and the blank control group (P < 0.05). These data indicate that the novel cellulose composite is a promising implantable hemostatic material in clinical settings.

Multi-functional wound dressings based on silicate bioactive materials

Most traditional wound dressings passively offer a protective barrier for the wounds, which lacks the initiative in stimulating tissue regeneration. In addition, cutaneous wound healing is usually accompanied by various complicated conditions, including bacterial infection, skin cancer, and damaged skin appendages, bringing further challenges for wound management in clinic. Therefore, an ideal wound dressing should not only actively stimulate wound healing but also hold multi-functions for solving problems associated with different specific wound conditions. Recent studies have demonstrated that silicate bioceramics and bioglasses are one type of promising materials for the development of wound dressings, as they can actively accelerate wound healing by regulating endothelial cells, dermal fibroblasts, macrophages, and epidermal cells. In particular, silicate-based biomaterials can be further functionalized by specific structural design or doping with functional components, which endow materials with enhanced bioactivities or expanded physicochemical properties such as photothermal, photodynamic, chemodynamic, or imaging properties. The functionalized materials can be used to address wound healing with different demands including but not limited to antibacterial, anticancer, skin appendages regeneration, and wound monitoring. In this review, we summarized the current research on the development of silicate-based multi-functional wound dressings and prospected the development of advanced wound dressings in the future.

Iota-carrageenan/xyloglucan/serine powders loaded with tranexamic acid for simultaneously hemostatic, antibacterial, and antioxidant performance

This study sought to prepare powder hemostats based on iota-carrageenan (ιC), xyloglucan (XYL), l-serine (SER), and tranexamic acid (TA). The powder form was chosen because it enables the hemostat to be used in wounds of any shape and depth. The powder hemostats showed irregular shapes and specific surface areas ranging from 34 to 46 m²/g. Increasing TA amount decreases the specific surface area, bulk density, water and blood absorption, and the antibacterial activities of the powder hemostats, but not the water retention ability. Conversely, in vitro biodegradation was positively impacted by increasing the TA content in the powder hemostats. In both the in vitro and in vivo tests, powder hemostats showed reduced bleeding time, significant adhesion of red blood cells, great hemocompatibility, moderate antioxidant activity, and high biocompatibility. These findings shed new light on designing powder hemostats with intrinsic antibacterial and antioxidant activity and excellent hemostatic performance.

Expandable, biodegradable, bioactive quaternized gelatin sponges for rapidly controlling incompressible hemorrhage and promoting wound healing

Designing expandable sponges with biodegradability and effective antibacterial properties are the urgent challenge for incompressible hemorrhage and wound healing. In the present investigation, based on quaternized gelatin (QG) and oxidized dextran (OD), a series of expandable sponges (ODQG) with high-water absorption capacity and robust mechanical properties were prepared. ODQG had good biodegradability in vitro and in vivo, and had inherent antibacterial activity (90% for E. coli and 99.74% for S. aureus). Due to the synergy effect of electrostatic interaction and blood concentration, ODQG could effectively attract and activate red blood cells/platelets and accelerate the coagulation process. Therefore, ODQG showed better hemostatic performance than Kuaikang® gelatin sponges and gauzes in incompressible hemorrhage model. Furthermore, ODQG could regulate inflammatory factor (TNF-α) and cytokines (TGF-β, VEGF), and greatly promote wound healing process. The biodegradable sponges with excellent antibacterial properties might have potential application prospect for incompressible hemostasis and wound healing in the future.

Properties and digestibility of a novel porous starch from lotus seed prepared via synergistic enzymatic treatment

The objective was to investigate the effect of synergistic enzymatic treatment on the properties and digestibility of a novel C-type lotus seed porous starch (LPS). Scanning electron microscopy showed that the densest and most complete pores were formed on the surface of LPS when the concentration of enzymes added was 1.5% (LS-1.5E). With increases in enzyme addition, the oil and water absorption of the porous starch increased and reached maxima at 1.5% of enzyme. Increased in the specific surface area, total pore volume and average pore diameter of LPS were determined by low-temperature nitrogen adsorption, while when the enzymes exceeded 1.5%, there were no significant changes. Compared to lotus seed starch (LS), the particle size of LPS also decreased. With the increases in enzyme addition, LPS exhibited higher relative crystallinity and ordering structure by XRD and FTIR. The results by SAXS confirmed that LPS had higher ordered semi-crystalline lamellar and denser lamellar structure compared to LS. Low-field ¹H NMR spectroscopy indicated that the proportion of bound water in LPS increased, while the proportion of bulk water decreased. Moreover, the degree of hydrolysis of LPS was lower than that of LS, and the content of rapidly digestible starch decreased, while the content of slowly digestible starch and resistant starch increased with the enzyme addition, which was consistent with the structural properties.

Recent advances in materials for hemostatic management

Traumatic hemorrhage can be a fatal event, particularly when large quantities of blood are lost in a short period of time. Therefore, hemostasis has become a crucial part of emergency treatment. For small wounds, hemostasis can be achieved intrinsically depending on the body's own blood coagulation mechanism; however, for large-area wounds, particularly battlefield and complex wounds, materials delivering rapid and effective hemostasis are required. In parallel with the constant progress in science, technology, and society, advances in hemostatic materials have also undergone various iterations by integrating new ideas with old concepts. There are various natural and synthetic hemostatic materials, including hemostatic powders, adhesives, hydrogels, and tourniquets, for the treatment of severe external trauma. This review covers the differences among the currently available hemostatic materials and comprehensively describes the hemostatic effects of different materials based on the underlying mechanisms. Finally, solutions for current issues related to trauma bleeding are discussed, and the prospects of hemostatic materials are proposed.

Hemostatic materials in wound care

Blood plays an essential role in the human body. Hemorrhage is a critical cause of both military and civilian casualties. The human body has its own hemostatic mechanism that involves complex processes and has limited capacity. However, in emergency situations such as battlefields and hospitals, when the hemostatic mechanism of the human body itself cannot stop bleeding effectively, hemostatic materials are needed for saving lives. In this review, the hemostatic mechanisms and performance of the most commonly used hemostatic materials, (including fibrin, collagen, zeolite, gelatin, alginate, chitosan, cellulose and cyanoacrylate) and the commercial wound dressings based on these materials, will be discussed. These materials may have limitations, such as poor tissue adhesion, risk of infection and exothermic reactions, that may lessen their hemostatic efficacy and cause secondary injuries. High-performance hemostatic materials, therefore, have been designed and developed to improve hemostatic efficiency in clinical use. In this review, hemostatic materials with advanced performances, such as antibacterial capacity, superhydrophobicity/superhydrophilicity, superelasticity, high porosity and/or biomimicry, will be introduced. Future prospects of hemostatic materials will also be discussed in this review.

Application and outlook of topical hemostatic materials: a narrative review

Bleeding complications can cause significant morbidities and mortalities in both civilian and military conditions. The formation of stable blood clots or hemostasis is essential to prevent major blood loss and death from excessive bleeding. However, the body's self-coagulation process cannot accomplish timely hemostasis without the assistance of hemostatic agents under some conditions. In the past two decades, topical hemostatic materials and devices containing platelets, fibrin, and polysaccharides have been gradually developed and introduced to induce faster or more stable blood clot formation, updating or iterating traditional hemostatic materials. Despite the various forms and functions of topical hemostatic materials that have been developed for different clinical conditions, uncontrolled hemorrhage still causes over 30% of trauma deaths across the world. Therefore, it is important to fabricate fast, efficient, safe, and ready-to-use novel hemostatic materials. It is necessary to understand the coagulation process and the hemostatic mechanism of different materials to develop novel topical hemostatic agents, such as tissue adhesives and sealants from various natural and synthetic materials. This review discusses the structural features of topical hemostatic materials related to the stimulation of hemostasis, summarizes the commercially available products and their applications, and reviews the ongoing clinical trials and recent studies concerning the development of different hemostatic materials.

In-vitro and in-vivo evaluation of modified sodium starch glycolate for exploring its haemostatic potential

The control of blood flow from breached blood vessels during surgery or trauma is challenging. With the existing treatment options being either expensive or ineffective, the development of a haemostat that overcome such drawbacks would be beneficial. With an aim to develop an ideal haemostat, the potential of sodium starch glycolate (SSG), a commonly used pharmaceutical disintegrant was modified to obtain porous microparticles (pSSG). The biodegradability, cyto-compatibility and haemo-compatibility of the modified particles were confirmed using appropriate studies. In comparison to starch and SSG, the irregular shaped pSSG demonstrated spontaneous and significant fluid absorption (3500+500 %) and formed a physical barrier to blood flow. In addition, significant blood cells aggregation and platelet activation was observed in the modified micoparticles leading to rapid clot formation. In-vivo studies on liver and abdominal artery injury models in rats indicated the superior haemostatic potential of pSSG over SSG and starch. The results indicated that pSSG can be explored further in clinical evaluation as a hemostat.

Absorbable nanocomposites composed of mesoporous bioglass nanoparticles and polyelectrolyte complexes for surgical hemorrhage control

Absorbable polyelectrolyte complexes-based hemostats are promising for controlling hemorrhage in iatrogenic injuries during surgery, whereas their hemostatic efficacy and other performances require further improvement for clinical application. Herein, spherical mesoporous bioglass nanoparticles (mBGN) were fabricated, and mBGN-polyelectrolyte complexes (composed of carboxymethyl starch and chitosan oligosaccharide) nanocomposites (BGN/PEC) with different mBGN contents were prepared via in situ coprecipitation followed by lyophilization. The effect of various mBGN content (10 and 20 wt%) on morphology, zeta potential, water absorption, degradation behavior and ion release were systematically evaluated. The in vitro degradability was dramatically promoted and a more neutral environment was achieved with the incorporation of mBGN, which is preferable for surgical applications. The in vitro coagulation test with whole blood demonstrated that the incorporation of mBGN facilitated blood clotting process. The plasma coagulation evaluation indicated that BGN/PEC had increased capability to accelerate coagulation cascade via the intrinsic pathway than that of the PEC, while have inapparent influence on the extrinsic and common pathway. The in vivo hemostatic evaluation in a rabbit hepatic hemorrhage model revealed that BGN/PEC with 10 wt% mBGN (10BGN/PEC) treatment group had the lowest blood loss, although its hemostatic time is close to that of 20BGN/PEC treatment group. The cytocompatibility evaluation with MC3T3-L1 fibroblasts indicated that 10BGN/PEC induced a ~25% increase of cell viability compared to the PEC at days 4 and 7, indicating improved biocompatibility. These findings support the promising application of absorbable BGN/PEC with optimized mBGN content as internal hemostats and present a platform for further development of PEC-based hemostats.

Oxidized cellulose-based hemostatic materials

The application of hemostatic agents is essential to prevent significant blood loss and death from excessive bleeding in surgical or emergency scenarios. Oxidized cellulose is an excellent biodegradable and biocompatible derivate of cellulose, which has become one of the most important hemostatic agents used in surgical procedures. However, to date, there has been no comprehensive report assessing oxidized cellulose-based hemostatic materials. Hence, this paper first reviewed the oxidation preparation, cellulose origin and structure, as well as biodegradability and safety of oxidized cellulose. Then a comprehensive review regarding the hemostatic mechanisms, various forms, modification, and current commercially available products of oxidized cellulose is discussed, which emphatically presents the most significant developments in the recent scientific literature. In conclusion, this paper summarizes the latest developments in oxidized cellulose-based hemostatic materials and provides a reference for further research and development in this field.

Peptide-immobilized starch/PEG sponge with rapid shape recovery and dual-function for both uncontrolled and noncompressible hemorrhage

It is challenging for traditional hemostatic sponges to meet the clinic demand for both uncontrolled and noncompressible hemorrhage. With the aim to develop a rapid shape recovery material with both active and passive hemostatic performance, a dual-functional hemostatic sponge (TRAP-Sp) with a macroporous structure and good mechanical properties for controlling massive and noncompressible hemorrhage was prepared by chemically immobilizing thrombin-receptor-agonist-peptide (TRAP) onto a starch/polyethylene glycol (PEG) sponge. The TRAP2-Sp1 showed the best hemostatic performance among all samples in both rat artery uncontrollable hemorrhage and liver defect noncompressible hemorrhage models. When analyzing the hemostatic mechanism of TRAP-Sp, the high water absorption capacity of the sponge contributed to absorbing plasma, concentrating blood cells, and enhancing blood coagulation. After absorbing water, the shape-fixed TRAP-Sp with sufficient mechanical strength and high resilience can rapidly expand and apply pressure to the wound. TRAP immobilized on the sponge could activate the adhered platelets in an active pathway. Additionally, evaluation of cytotoxicity, hemolysis, and histology further highlighted the adequate biocompatibility of TRAP-Sp. With excellent hemostatic performance and biosafety, this sponge could be a potential candidate as a topical hemostatic agent for uncontrolled and noncompressible hemorrhage. STATEMENT OF SIGNIFICANCE: There is a need for innovative hemostatic materials for both uncontrolled and noncompressible hemorrhage. This manuscript describes a rapid shape recovery hemostatic sponge with both active and passive hemostatic performances synthesized by foaming technique, cross-linking reaction, and chemical immobilization of thrombin-receptor-agonist-peptide (TRAP). On contact with blood, the shape-fixed sponge can not only rapidly recover its original shape and concentrate platelets and RBCs but also activate the adhered platelets efficiently. The dual-functional sponge has excellent hemostatic efficacy in rat femoral artery hemorrhage and can control noncompressible hemorrhage in penetrating liver wound. Thus, we believe that this sponge could be a potential candidate as a topical hemostatic agent for uncontrolled and noncompressible hemorrhage.

Influence of the physicochemical characteristics of diatom frustules on hemorrhage control

Diatom frustules are good resources for hemostasis agent production.

Well-ordered mesoporous silica and bioactive glasses: promise for improved hemostasis

Mesoporous silica and bioactive glasses with unique textural properties are new generations of inorganic hemostats with efficient hemostatic ability.

Evaluation of absorbable hemostatic agents of polyelectrolyte complexes using carboxymethyl starch and chitosan oligosaccharide both in vitro and in vivo

CMS/COS PECs with a suitable COS content were promising absorbable hemostatic agents for internal use.

Porous chitosan microspheres containing zinc ion for enhanced thrombosis and hemostasis

Quick hemostats for non-lethal massive traumatic bleeding in battlefield and civilian accidents are important for reducing mortality and medical costs. Chitosan (CS) has been widely used as a clinic hemostat. To enhance its hemostatic efficiency, Zn²⁺ in the form of zinc alginate (ZnAlg) was introduced to CS to make porous CS@ZnAlg microspheres with ZnAlg component on the surface. Such microspheres were prepared by successive steps of micro-emulsion, polyelectrolyte adhesion, and thermally induced phase separation. Their structure and hemostatic performance were analyzed by SEM, FT-IR, XPS and a series of in vitro hemostatic experiments including thromboelastography analysis. The composite microspheres had an outer and internal interconnected porous structure. Their size, surface area, and water absorption ratio were ca. 70μm, 48m²/g, and 1850%, respectively. Compared to the neat chitosan microspheres, the CS@ZnAlg microspheres showed shorter onset of clot formation, much faster in vitro and in vivo whole blood clotting, bigger clot, less blood loss, and shorter hemostatic time in the rat liver laceration and tail amputation models. The synergetic hemostatic effects from (1) the electrostatic attraction between chitosan component and red blood cells, (2) the activation of coagulation factor XII by Zn²⁺ of zinc alginate component, and (3) physical blocking by microsphere matrix, contributed to the enhanced hemostatic performance of CS@ZnAlg microspheres.