Development of Metal Ion Binded Oxidized Regenerated Cellulose Powder as Hemostatic Agent: A Comparative Study with in Vivo Performance

Sheet-like Janus hemostatic dressings with synergistic effects of cardanol hemostasis and quaternary ammonium salt antibacterial action

It is of utmost importance that bleeding should be stopped and infection be prevented in people with trauma. In this study, an anisotropic Janus mesoporous silica nanosheet (MSNS) with different functional groups was designed and prepared. In order to endow both sides of the MSNS with independent fast hemostasis and effective antibacterial action, the MSNS was modified with cardanol (CA) and 2,3-epoxypropyltrimethylammonium (GTA). The addition of CA significantly improved the hemostatic property of the MSNS. In a SD rat femoral artery injury model, the hemostatic time of CA-MSNS-GTA was 47% shorter than that of the MSNS, attributed to the sealing of the hydrophobic alkyl side chain and the adhesion of phenolic hydroxyl groups in CA. CA-MSNS-GTA could form a three-dimensional network with fibrin to further accelerate the coagulation process. This Janus material exhibited excellent antibacterial effects (∼90%) against Gram-positive bacteria (S. pneumoniae) and Gram-negative bacteria (E. coli) due to the presence of GTA. The cytotoxicity test showed that CA-MSNS-GTA exhibited biosafety, which provided safety guarantee for clinical applications in the future. This Janus dressing with different functions on two opposite sides provides synergetic multifunctional effects during wound healing.

Recent advances in biopolymer-based hemostatic materials

Hemorrhage is the leading cause of trauma-related deaths, in hospital and pre-hospital settings. Hemostasis is a complex mechanism that involves a cascade of clotting factors and proteins that result in the formation of a strong clot. In certain surgical and emergency situations, hemostatic agents are needed to achieve faster blood coagulation to prevent the patient from experiencing a severe hemorrhagic shock. Therefore, it is critical to consider appropriate materials and designs for hemostatic agents. Many materials have been fabricated as hemostatic agents, including synthetic and naturally derived polymers. However, compared to synthetic polymers, natural polymers or biopolymers, which include polysaccharides and polypeptides, have greater biocompatibility, biodegradability, and processibility. Thus, in this review, we focus on biopolymer-based hemostatic agents of different forms, such as powder, particles, sponges, and hydrogels. Finally, we discuss biopolymer-based hemostats currently in clinical trials and offer insight into next-generation hemostats for clinical translation.

Nanoporous and nano thickness film-forming bioactive composition for biomedical applications

Unmanageable bleeding is one of the significant causes of mortality. Attaining rapid hemostasis ensures subject survivability as a first aid during combats, road accidents, surgeries that reduce mortality. Nanoporous fibers reinforced composite scaffold (NFRCS) developed by a simple hemostatic film-forming composition (HFFC) (as a continuous phase) can trigger and intensify hemostasis. NFRCS developed was based on the dragonfly wing structure's structural design. Dragonfly wing structure consists of cross-veins and longitudinal wing veins inter-connected with wing membrane to maintain the microstructural integrity. The HFFC uniformly surface coats the fibers with nano thickness film and interconnects the randomly distributed cotton gauge (Ct) (dispersed phase), resulting in the formation of a nanoporous structure. Integrating continuous and dispersed phases reduce the product cost by ten times that of marketed products. The modified NFRCS (tampon or wrist band) can be used for various biomedical applications. The in vivo studies conclude that the developed Cp NFRCS triggers and intensifies the coagulation process at the application site. The NFRCS could regulate the microenvironment and act at the cellular level due to its nanoporous structure, which resulted in better wound healing in the excision wound model.

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.

Chitosan-Based Thermo-Sensitive Hydrogel Loading Oyster Peptides for Hemostasis Application

Uncontrolled massive hemorrhage is one of the principal causes of death in trauma emergencies. By using catechol-modified chitosan (CS-C) as the matrix material and β glycerol phosphate (β-GP) as a thermo-sensitive agent, chitosan-based thermo-sensitive hydrogel loading oyster peptides (CS-C/OP/β-GP) were prepared at physiological temperature. The hemostatic performance of CS-C/OP/β-GP hydrogel was tested in vivo and in vitro, and its biological safety was evaluated. The results showed that the in vitro coagulation time and blood coagulation index of CS-C/OP/β-GP hydrogel were better than those of a commercial gelatin sponge. Notably, compared with the gelatin sponge, CS-C/OP/β-GP hydrogel showed that the platelet adhesion and erythrocyte adsorption rates were 38.98% and 95.87% higher, respectively. Additionally, the hemostasis time in mouse liver injury was shortened by 19.5%, and the mass of blood loss in the mouse tail amputation model was reduced by 18.9%. The safety evaluation results demonstrated that CS-C/OP/β-GP had no cytotoxicity to L929 cells, and the hemolysis rates were less than 5% within 1 mg/mL, suggesting good biocompatibility. In conclusion, our results indicate that CS-C/OP/β-GP is expected to be a promising dressing in the field of medical hemostasis.

Recent Advances on Synthetic and Polysaccharide Adhesives for Biological Hemostatic Applications

Rapid hemostasis and formation of stable blood clots are very important to prevent massive blood loss from the excessive bleeding for living body, but their own clotting process cannot be completed in time for effective hemostasis without the help of hemostatic materials. In general, traditionally suturing and stapling techniques for wound closure are prone to cause the additional damages to the tissues, activated inflammatory responses, short usage periods and inevitable second operations in clinical applications. Especially for the large wounds that require the urgent closure of fluids or gases, these conventional closure methods are far from enough. To address these problems, various tissue adhesives, sealants and hemostatic materials are placed great expectation. In this review, we focused on the development of two main categories of tissue adhesive materials: synthetic polymeric adhesives and naturally derived polysaccharide adhesives. Research of the high performance of hemostatic adhesives with strong adhesion, better biocompatibility, easy usability and cheap price is highly demanded for both scientists and clinicians, and this review is also intended to provide a comprehensive summarization and inspiration for pursuit of more advanced hemostatic adhesives for biological fields.

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.

Poly(lactide-co-glycolide) grafted hyaluronic acid-based electrospun fibrous hemostatic fragments as a sustainable anti-infection and immunoregulation material

Poly(lactide-co-glycolide) (PLGA) copolymers are promising synthetic materials in the biomedical field. However, in wound management, their hydrophobic properties limit their further application because of their poor adhesion to the surface of moist wounds. Furthermore, the lack of hemostatic materials with sustainable anti-infection and immunoregulation functions remains a highly significant clinical problem, as commercially available hemostatic products, such as Arista™, Celox™ and QuikClot™, do not have sufficient infection prevention and immunoregulation properties. Herein, we employ electrospinning, ammonia dissociation and surface grafting techniques to develop a series of PLGA-based hemostatic materials, including a PLGA electrospun fibrous membrane, PLGA-NH2 fibrous particles and PLGA-hyaluronic acid fibrous fragments (PLGA-HA FFs). Notably, we load azithromycin on the PLGA-HA FFs to endow them with anti-infection and immunoregulation properties. The hemostatic mechanism analysis demonstrates that the PLGA-HA FFs show superior hemostasis performance compared to traditional gauzes. The results show that the PLGA-HA FFs can act as a versatile platform with high encapsulation of azithromycin (83.03% ± 2.81%) and rapid hemostasis (28 ± 2 s) as well as prominent cytocompatibility towards L929 cells, RAW 264.7 cells and red blood cells. We believe that the current research proposes a possible strategy to synthesize materials that achieve not only safe and effective hemostasis, but also have anti-infection and immunoregulation properties for the development of further hemostatic products.

Oxidized regenerated cellulose cross-linked gelatin microparticles for rapid and biocompatible hemostasis: A versatile cross-linking agent

Effective hemostatic materials are of utmost importance for preventing bleeding in emergencies and critical injuries. Combining biodegradability, good hemostatic properties and biocompatibility, gelatin is one of the most reliable materials clinically used for preventing internal bleeding in surgeries and for stopping external hemorrhage. Cross-linking is a useful method for enhancing the absorption capacity of gelatin and for controlling the degradation process. Existing and commonly used aldehyde-containing cross-linking agents lack reliability with respect to the control of hemostatic effect, solubility and toxicity. In this study; gelatin was cross-linked with sodium oxidized regenerated cellulose (NaORC) to produce hemostatic microparticles. The NaORC was used at different ratios; and the studies on hemostatic efficiency and cytotoxicity under in vitro conditions demonstrated rapid arrest of bleeding alongside biocompatibility. These microparticles employing NaORC as a cross-linking agent for the first time demonstrated a unique structure for stopping bleeding with biocompatibility, and opened the way for different forms of cross-linked structures to be used in other biomaterials applications.

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.

Porous chitosan microspheres for application as quick in vitro and in vivo hemostat

Controlling massive hemorrhage is of great importance to lower transfusional medical cost, and to reduce death and mobility rate in battlefield and civilian accidents. We reported the fabrication of porous chitosan microspheres (CSMS) with tunable surface pore size by microemulsion combined with thermally induced phase separation technique, and its application as a quick hemostat. Their hemostatic property was characterized by blood clotting kinetics, adherence interaction between red blood cells/platelets and CSMS, in vitro and in vivo hemostasis by rat tail amputation and liver laceration models, and histological analysis. Their density, surface area, porosity, water absorption ratio were 0.04-0.06g/cm³, 28.2-31.5m²/g, 98%, and 15.5-23.2g/g, respectively. The surface pore was controlled to be smaller than 2.0μm. The porous CSMS showed increasing hemostatic efficacy with decreasing surface pore size. Compared to the conventional compact chitosan particles (CCSP), the porous CSMS had much improved in vitro and in vivo hemostatic potential with respect to formation of blood clot, hemostatic time, and blood loss. For instance, the hemostatic time and blood loss of CSMS in the rat liver laceration model were down to respectively 70s and 0.026g from 175s and 0.28g of CCSP. Histological examination showed that application of porous CSMS to liver laceration caused no destruction of underlying hepatocytes, inflammatory reaction, and thermal injury to liver tissue. The porous CSMS is a biodegradable, quick and safe hemostat, which can be used in various wounds including complex and non-compressive ones.

Design and development of polysaccharide hemostatic materials and their hemostatic mechanism

The formation of stable blood clots or hemostasis is essential to prevent major blood loss and death from excessive bleeding.