Synergistic enhancement of hemostatic performance of mesoporous silica by hydrocaffeic acid and chitosan

Biomimetic poly(thioctic acid)-based bioadhesive hydrogels for wet adhesion, expeditious hemostasis and enhanced wound healing

The bioadhesive hydrogels have been viewed as promising substitutes for surgical sutures in wound closure. However, current bioadhesives face challenges such as weak wet adhesion and hemostatic performance, which hinder their wider clinical application. In this study, a novel poly(thioctic acid)Li+/caffeic acid-grafted sericin (CAS) (PTALi-CAS) supramolecular hydrogel was prepared using facile one-pot method. Among the PTALi-CAS hydrogels with varying CAS content, the PTALi-7%CAS hydrogels exhibited the highest adhesion strength (32.02 ± 2.28 kPa) and could adhere on surfaces of various organs in moist environments. It is noteworthy that the microstructure of the PTALi-7%CAS hydrogels after stretching closely resemble those of mussel byssal adhesion proteins. Additionally, the PTALi-7%CAS hydrogels exhibited rapid hemostatic properties in rat hemorrhage models and significantly accelerated the wound healing in rat skin incision experiments. Therefore, this study proposes a promising approach for developing a versatile hydrogel to aid in healing traumatic wounds.

Recent advances in mesoporous silica nanoparticles formulations and drug delivery for wound healing

Wound healing is a natural process that can be disrupted by disease. Nanotechnology is a promising platform for the development of new therapeutic agents to accelerate acute and chronic wound healing. Drug delivery by means of nanoparticles as well as wound dressings have emerged as suitable options to improving the healing process. The characteristics of mesoporous silica nanoparticles (MSNs) make them efficient carriers of pharmaceutical agents alone or in combination with dressings. In order to maximize the effect of a drug and minimize its adverse consequences, it may be possible to include targeted and intelligent release of the drug into the design of MSNs. Its use to facilitate closure of adjacent sides of a cut as a tissue adhesive, local wound healing, controlled drug release and induction of blood coagulation are possible applications of MSNs. This review summarizes research on MSN applications for wound healing. It includes a general overview, wound healing phases, MSN formulation, therapeutic possibilities of MSNs and MSN-based drug delivery systems for wound healing.

Surface-modified, zinc-incorporated mesoporous silica nanoparticles with improved antibacterial and rapid hemostatic properties

Severe bleeding and bacterial infections pose significant challenges to the global public health. Effective hemostatic materials have the potential to be used for rapid control of bleeding at the wound site. In this study, mesoporous silica nanoparticles (MSN) were doped with zinc ions (MSN@Zn) and subsequently functionalized with carboxyl (-COOH) groups through post-grafting, resulting in (MSN@Zn-COOH). The results demonstrated the successful functionalization of carboxyl groups on the surface of MSN@Zn mesoporous materials with minimal impact on the morphology. The released zinc ions showed potent antibacterial activity (above ∼80 %) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In vitro and in vivo assessments of MSN@Zn-COOH revealed excellent hemostatic effects and favorable blood compatibility. Hemolysis percentages associated with MSN@Zn-COOH exhibited noteworthy reductions in comparison to MSN. Furthermore, a decrease in APTT (a test evaluating the intrinsic coagulation pathway) of modified MSN@Zn indicated enhanced hemostasis, supported by their negative zeta potential (∼ -14 to -43 mV). Importantly, all samples showed no cytotoxicity. This work underscores the potential of MSN@Zn-COOH, with its combined hemostatic performance and antibacterial activity, for emergency clinical applications.

Sodium alginate/carboxycellulose/polydopamine composite microspheres for rapid hemostasis of deep irregular wounds

Hemostasis of deep irregular wounds is a severe problem in clinical practice. The development of rapid-acting hemostatic agents for deep and irregular wound is urgently needed. Here, sodium alginate/carboxycellulose/polydopamine (SA/CNF/PDA) microspheres was prepared by reverse emulsification and crosslinking with Ca2+, and SA/CNF/PDA composite hemostatic microspheres with porous structure were obtained by freeze-drying. SA/CNF/PDA composite hemostatic microspheres exhibited excellent porosity and water absorption which could rapidly absorb blood on the wound surface. Moreover, SA/CNF/PDA composite microspheres demonstrated remarkable hemostatic capabilities both in vitro and in vivo. It exhibited strong hemostatic performance in models of mouse tail-break and liver damage. Especially in liver injury model, it was completely hemostatic in 95 s, and blood loss (19.3 mg). The hemostatic efficacy of the SA/CNF/PDA composite microspheres was amplified through the stimulation of both exogenous and endogenous coagulation pathways. Therefore, SA/CNF/PDA composite hemostatic microspheres are suitable for rapid hemostasis of deep irregular wounds which are potential rapid hemostatic material for surgical application.

Engineering mesoporous bioactive glasses for emerging stimuli-responsive drug delivery and theranostic applications

Mesoporous bioactive glasses (MBGs), which belong to the category of modern porous nanomaterials, have garnered significant attention due to their impressive biological activities, appealing physicochemical properties, and desirable morphological features. They hold immense potential for utilization in diverse fields, including adsorption, separation, catalysis, bioengineering, and medicine. Despite possessing interior porous structures, excellent morphological characteristics, and superior biocompatibility, primitive MBGs face challenges related to weak encapsulation efficiency, drug loading, and mechanical strength when applied in biomedical fields. It is important to note that the advantageous attributes of MBGs can be effectively preserved by incorporating supramolecular assemblies, miscellaneous metal species, and their conjugates into the material surfaces or intrinsic mesoporous networks. The innovative advancements in these modified colloidal inorganic nanocarriers inspire researchers to explore novel applications, such as stimuli-responsive drug delivery, with exceptional in-vivo performances. In view of the above, we outline the fabrication process of calcium-silicon-phosphorus based MBGs, followed by discussions on their significant progress in various engineered strategies involving surface functionalization, nanostructures, and network modification. Furthermore, we emphasize the recent advancements in the textural and physicochemical properties of MBGs, along with their theranostic potentials in multiple cancerous and non-cancerous diseases. Lastly, we recapitulate compelling viewpoints, with specific considerations given from bench to bedside.

A Self-Assembly Pro-Coagulant Powder Capable of Rapid Gelling Transformation and Wet Adhesion for the Efficient Control of Non-Compressible Hemorrhage

Rapid and effective control of non-compressible massive hemorrhage poses a great challenge in first-aid and clinical settings. Herein, a biopolymer-based powder is developed for the control of non-compressible hemorrhage. The powder is designed to facilitate rapid hemostasis by its excellent hydrophilicity, great specific surface area, and adaptability to the shape of wound, enabling it to rapidly absorb fluid from the wound. Specifically, the powder can undergo sequential cross-linking based on "click" chemistry and Schiff base reaction upon contact with the blood, leading to rapid self-gelling. It also exhibits robust tissue adhesion through covalent/non-covalent interactions with the tissues (adhesive strength: 89.57 ± 6.62 KPa, which is 3.75 times that of fibrin glue). Collectively, this material leverages the fortes of powder and hydrogel. Experiments with animal models for severe bleeding have shown that it can reduce the blood loss by 48.9%. Studies on the hemostatic mechanism also revealed that, apart from its physical sealing effect, the powder can enhance blood cell adhesion, capture fibrinogen, and synergistically induce the formation of fibrin networks. Taken together, this hemostatic powder has the advantages for convenient preparation, sprayable use, and reliable hemostatic effect, conferring it with a great potential for the control of non-compressible hemorrhage.

Bioadhesive Technology Platforms

Bioadhesives have emerged as transformative and versatile tools in healthcare, offering the ability to attach tissues with ease and minimal damage. These materials present numerous opportunities for tissue repair and biomedical device integration, creating a broad landscape of applications that have captivated clinical and scientific interest alike. However, fully unlocking their potential requires multifaceted design strategies involving optimal adhesion, suitable biological interactions, and efficient signal communication. In this Review, we delve into these pivotal aspects of bioadhesive design, highlight the latest advances in their biomedical applications, and identify potential opportunities that lie ahead for bioadhesives as multifunctional technology platforms.

Multifunctional Chitosan Scaffold Platforms Loaded with Natural Polyphenolic Extracts for Wound Dressing Applications

Chitosan (CS)-based scaffolds loaded with Pinus radiata extract bark (PE) and grape seed extract (GSE) were successfully developed for wound dressing applications. The effects of incorporating GSE and PE in CS scaffolds were investigated in relation to their physicochemical and biological properties. All scaffolds exhibited porous structures with the ability to absorb more than 70 times their weight when contacted with blood and phosphate buffer solution. The incorporation of GSE and PE into the CS scaffolds increased their blood absorption ability and degradation rates over time. All scaffolds showed a clotting ability above 95%, with their surfaces being favorable for red blood cell attachment. Both GSE and PE were released from the CS scaffolds in a sustained manner. Scaffolds loaded with GSE and PE inhibited the bacterial activity of S. aureus and E. coli by 40% and 44% after 24 h testing. In vitro cell viability studies demonstrated that all scaffolds were nontoxic to HaCaT cells. Importantly, the addition of GSE and PE further increased cell viability compared to that of the CS scaffold. This study provides a new synthesis method to immobilize GSE and PE on CS scaffolds, enabling the formation of novel material platforms with a high potential for wound dressing applications.

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.

Mesoporous Materials Make Hydrogels More Powerful in Biomedicine

Scientists have been attempting to improve the properties of mesoporous materials and expand their application since the 1990s, and the combination with hydrogels, macromolecular biological materials, is one of the research focuses currently. Uniform mesoporous structure, high specific surface area, good biocompatibility, and biodegradability make the combined use of mesoporous materials more suitable for the sustained release of loaded drugs than single hydrogels. As a joint result, they can achieve tumor targeting, tumor environment stimulation responsiveness, and multiple therapeutic platforms such as photothermal therapy and photodynamic therapy. Due to the photothermal conversion ability, mesoporous materials can significantly improve the antibacterial ability of hydrogels and offer a novel photocatalytic antibacterial mode. In bone repair systems, mesoporous materials remarkably strengthen the mineralization and mechanical properties of hydrogels, aside from being used as drug carriers to load and release various bioactivators to promote osteogenesis. In hemostasis, mesoporous materials greatly elevate the water absorption rate of hydrogels, enhance the mechanical strength of the blood clot, and dramatically shorten the bleeding time. As for wound healing and tissue regeneration, incorporating mesoporous materials can be promising for enhancing vessel formation and cell proliferation of hydrogels. In this paper, we introduce the classification and preparation methods of mesoporous material-loaded composite hydrogels and highlight the applications of composite hydrogels in drug delivery, tumor therapy, antibacterial treatment, osteogenesis, hemostasis, and wound healing. We also summarize the latest research progress and point out future research directions. After searching, no research reporting these contents was found.

Optimization Preparation and Evaluation of Chitosan Grafted Norfloxacin as a Hemostatic Sponge

Considering the great harm to the human body caused by severe and massive bleeding, in this study, chitosan-grafted norfloxacin (CTS-NF) composites were prepared with chitosan (CTS) and norfloxacin (NF) as raw materials by a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-mediated coupling method to solve the limitations of slow hemostatic and poor anti-infective effects of current dressings on the market. The effects of the mass ratio of CTS to NF (M_CTS/M_NF), reaction temperature T and reaction time t on the grafting rate (η%) of the products were investigated through single factor tests. The preparation process was optimized with the η% as an evaluation index by means of the Box-Behnken test design and response surface analysis. The antimicrobial activity was evaluated by inhibition zone assay, and the hemostatic activity of the prepared composites was evaluated in vitro and in vivo. The results suggested that the optimum preparation conditions were the mass ratio of CTS to NF (M_CTS/M_NF) 5:3, reaction temperature 65 °C, and reaction time 4 h. Under this condition, the η% of CTS-NF was 45.5%. The CTS-NF composites displayed significant antimicrobial activities. Moreover, in vitro hemostasis results revealed that the CTS-NF composite had a lower blood clotting index and absorbed red blood cells to promote aggregation. In vivo ear and live hemostasis, the CTS-NF groups showed short hemostatic time (49.75 ± 3.32 s and 50.00 ± 7.21 s) and more blood loss (0.07 ± 0.010 g and 0.075 ± 0.013 g). The results showed that CTS-NF reduced the bleeding time and volume, exhibiting a significant coagulation effect. Therefore, the CTS-NF sponge is expected to be a new, effective hemostatic and antibacterial material in the future.

Synthesis of Carbon Dots with Hemostatic Effects Using Traditional Chinese Medicine as a Biomass Carbon Source

As novel nanomaterials developed gradually with nanotechnology, carbon dots have been widely applied in medical applications, including disease treatment, drug delivery, antibacterial applications, and phototherapy. Based on the similar process between Chinese medicinal materials for hemostasis and modern carbon dots, this paper reports the preparation of four luminescent carbon dots with Chinese medicinal materials (plants and animals) as carbon sources and the investigation on their hemostatic effects in vitro and in rat bleeding models. It is found that the four studied carbon dots exhibit similar hemostatic effects and hemostatic mechanisms through impacting both endogenous and exogenous coagulation pathways. In addition, these carbon dots all exhibit anti-inflammatory effects and good biocompatibility, ensuring their potential in pretraumatic fields. This work provides a new perspective for hemostatic carbon dots prepared using carbonized natural plants and animals and new ideas for the research of new hemostatic materials.

Design of biopolymer-based hemostatic material: Starting from molecular structures and forms

Uncontrolled bleeding remains as a leading cause of death in surgical, traumatic, and emergency situations. Management of the hemorrhage and development of hemostatic materials are paramount for patient survival. Owing to their inherent biocompatibility, biodegradability and bioactivity, biopolymers such as polysaccharides and polypeptides have been extensively researched and become a focus for the development of next-generation hemostatic materials. The construction of novel hemostatic materials requires in-depth understanding of the physiological hemostatic process, fundamental hemostatic mechanisms, and the effects of material chemistry/physics. Herein, we have recapitulated the common hemostatic strategies and development status of biopolymer-based hemostatic materials. Furthermore, the hemostatic mechanisms of various molecular structures (components and chemical modifications) are summarized from a microscopic perspective, and the design based on them are introduced. From a macroscopic perspective, the design of various forms of hemostatic materials, e.g., powder, sponge, hydrogel and gauze, is summarized and compared, which may provide an enlightenment for the optimization of hemostat design. It has also highlighted current challenges to the development of biopolymer-based hemostatic materials and proposed future directions in chemistry design, advanced form and clinical application.

Nano-Enabled Chronic Wound Healing Strategies: Burn and Diabetic Ulcer Wounds

The human skin serves as the body’s first line of defense against the environment. Diabetes mellitus (DM) and 2nd–4th degree burns, on the other hand, affect the skin’s protective barrier features. Burn wounds, hypermetabolic state, and hyperglycemia compromise the immune system leading to chronic wound healing. Unlike acute wound healing processes, chronic wounds are affected by reinfections which can lead to limb amputation or death. The conventional wound dressing techniques used to protect the wound and provide an optimal environment for repair have their limitations. Various nanomaterials have been produced that exhibit distinct features to tackle issues affecting wound repair mechanisms. This review discusses the emerging technologies that have been designed to improve wound care upon skin injury. To ensure rapid healing and possibly prevent scarring, different nanomaterials can be applied at different stages of healing (hemostasis, inflammation, proliferation, remodeling).

Design of nanoconstructs that exhibit enhanced hemostatic efficiency and bioabsorbability

Hemorrhage is a prime cause of death in civilian and military traumatic injuries, whereby a significant proportion of death and complications occur prior to paramedic arrival and hospital resuscitation. Hence, it is crucial to develop hemostatic materials that are able to be applied by simple processes and allow control over bleeding by inducing rapid hemostasis, non-invasively, until subjects receive necessary medical care. This tutorial review discusses recent advances in synthesis and fabrication of degradable hemostatic nanomaterials and nanocomposites. Control of assembly and fine-tuning of composition of absorbable (i.e., degradable) hemostatic supramolecular structures and nanoconstructs have afforded the development of smart devices and scaffolds capable of efficiently controlling bleeding while degrading over time, thereby reducing surgical operation times and hospitalization duration. The nanoconstructs that are highlighted have demonstrated hemostatic efficiency pre-clinically in animal models, while also sharing characteristics of degradability, bioabsorbability and presence of nano-assemblies within their compositions.

Electrospun kaolin-loaded chitosan/PEO nanofibers for rapid hemostasis and accelerated wound healing

Development of chitosan-based hemostatic products and their application in wound healing has always been a research hotspot in the field of emergency treatment and biomedicine. In this study, the classic hemostatic chitosan and the most well-known inorganic hemostatic agent-kaolin were tried to combine to form a more excellent dressing. Together with the aid of non-toxic, harmless and good hydrophilic polyethylene oxide, chitosan/polyethylene oxide (PEO)/kaolin nanofiber membranes (CPKs) were prepared by electrospinning technology. Such membranes exhibited adjustable mechanical properties and good biocompatibility. Furthermore, a series of in vitro coagulation experiments proved that CPKs with 10 % ratio of kaolin (CPK10) has excellent hemostatic ability. Especially, in the whole blood coagulation time (WBCT) assay, the hemostatic time of CPK10 (43 ± 1.4 s) was significantly lower than that of chitosan/polyethylene oxide (CPK0) nanofiber membrane (61 ± 2.2 s) and QuikClot® Combat Gauze (55.7 ± 1.2 s). The further rat liver injury test reconfirmed that CPK10 can stop bleeding better and faster compared to other groups. In addition, CPKs could promote back wound healing in rats within 14 days without significant inflammatory response. This safe and effective hemostatic CPKs is expected to be a promising candidate hemostat in pre-hospital medical care.

Preparation of physically crosslinked polyelectrolyte Gelatin-Tannic acid-κ-Carrageenan (GTC) microparticles as hemostatic agents

In humans, excessive bleeding during civilian accidents, and surgery account for 40% of the mortality worldwide. Hence, the development of biocompatible hemostatic materials useful for rapid hemorrhage control has become a fundamental research problem in the biomedicine community. In this study, we prepared biocompatible gelatin-tannic acid-κ-carrageenan (GTC) microparticles using a facile Tween 80 stabilized water-in-oil (W/O) emulsion method for rapid hemostasis. The formation of GTC microparticles occurs via polyelectrolyte interactions between gelatin and k-carrageenan as well as hydrogen bonding from tannic acid. In addition, the GTC microparticles formulated in our study showed high water adsorption ability with a low volume-swelling ratio for a particle size of 46 μm. In addition, the GTC microparticles displayed >80% biocompatibility in NIH 3T3 cells and <5% hemocompatibility in hemolysis ratio tests. Notably, the GTC microparticles induced rapid blood clotting in 50 s and blood loss of approximately 46 mg in the femoral artery of BALB/c female mice with a 100% survival rate that was significantly better than the control group (blood clot time:250 s; blood loss: 259 mg). Thus, the findings from our study collectively suggest that GTC microparticles may play a promising clinical role in medical applications to tackle hemorrhage control.

Silica/Protein and Silica/Polysaccharide Interactions and Their Contributions to the Functional Properties of Derived Hybrid Wound Dressing Hydrogels

Multifunctional and biocompatible hydrogels are on the focus of wound healing treatments. Protein and polysaccharides silica hybrids are interesting wound dressing alternatives. The objective of this review is to answer questions such as why silica for wound dressings reinforcement? What are the roles and contributions of silane precursors and silica on the functional properties of hydrogel wound dressings? The effects of tailoring the porous, morphological, and chemical characteristics of synthetic silicas on the bioactivity of hybrid wound dressings hydrogels are explored in the first part of the review. This is followed by a commented review of the mechanisms of silica/protein and silica/polysaccharide interactions and their impact on the barrier, scaffold, and delivery matrix functions of the derived hydrogels. Such information has important consequences for wound healing and paves the way to multidisciplinary researches on the production, processing, and biomedical application of this kind of hybrid materials.

Haemostatic materials for wound healing applications

Wounds are one of the most common health issues, and the cost of wound care and healing has continued to increase over the past decade. The first step in wound healing is haemostasis, and the development of haemostatic materials that aid wound healing has accelerated in the past 5 years. Numerous haemostatic materials have been fabricated, composed of different active components (including natural polymers, synthetic polymers, silicon-based materials and metal-containing materials) and in various forms (including sponges, hydrogels, nanofibres and particles). In this Review, we provide an overview of haemostatic materials in wound healing, focusing on their chemical design and operation. We describe the physiological process of haemostasis to elucidate the principles that underpin the design of haemostatic wound dressings. We also highlight the advantages and limitations of the different active components and forms of haemostatic materials. The main challenges and future directions in the development of haemostatic materials for wound healing are proposed.

An Update on Mesoporous Silica Nanoparticle Applications in Nanomedicine

The efficient and safe delivery of therapeutic drugs, proteins, and nucleic acids are essential for meaningful therapeutic benefits. The field of nanomedicine shows promising implications in the development of therapeutics by delivering diagnostic and therapeutic compounds. Nanomedicine development has led to significant advances in the design and engineering of nanocarrier systems with supra-molecular structures. Smart mesoporous silica nanoparticles (MSNs), with excellent biocompatibility, tunable physicochemical properties, and site-specific functionalization, offer efficient and high loading capacity as well as robust and targeted delivery of a variety of payloads in a controlled fashion. Such unique nanocarriers should have great potential for challenging biomedical applications, such as tissue engineering, bioimaging techniques, stem cell research, and cancer therapies. However, in vivo applications of these nanocarriers should be further validated before clinical translation. To this end, this review begins with a brief introduction of MSNs properties, targeted drug delivery, and controlled release with a particular emphasis on their most recent diagnostic and therapeutic applications.

Chitosan/PDLLA-PEG-PDLLA solution preparation by simple stirring and formation into a hydrogel at body temperature for whole wound healing

Various chitosan (CS)-based dressings are used for wound treatment in clinical settings. Dressings that can be easily prepared and conveniently applied to treat wounds are highly desirable. In this study, a hybrid hydrogel was prepared using CS and poly (D,l-lactide)-poly (ethylene glycol)-poly (D,l-lactide) (PPP) through a simple process for convenient application. The optimal formula included a 7% CS PPP micellar solution, exhibiting excellent liquidity and allowing optional application as a spray. Molecular dynamic simulations indicated that CS and PPP established interactions via H-bonds and formed a long-chain complex, easily forming a hydrogel. Upon application, it rapidly transformed into a hydrogel and tightly adhered to the skin, forming a hemostatic (decreased 53.4%) and antibacterial (increased to about 90%) barrier, demonstrating accelerated wound healing (58.0%). This simple CS hybrid hydrogel can be easily prepared and applied and has potential applicability in clinical wound treatment.

Improving Fibrin Hydrogels' Mechanical Properties, through Addition of Silica or Chitosan-Silica Materials, for Potential Application as Wound Dressings

Fibrin is a protein-based hydrogel formed during blood coagulation. It can also be produced in vitro from human blood plasma, and it is capable of resisting high deformations. However, after each deformation process, it loses high amounts of water, which subsequently makes it mechanically unstable and, finally, difficult to manipulate. The objective of this work was to overcome the in vitro fibrin mechanical instability. The strategy consists of adding silica or chitosan-silica materials and comparing how the different materials electrokinetic-surface properties affect the achieved improvement. The siliceous materials electrostatic and steric stabilization mechanisms, together with plasma protein adsorption on their surfaces, were corroborated by DLS and ζ-potential measurements before fibrin gelling. These properties avoid phase separation, favoring homogeneous incorporation of the solid into the forming fibrin network. Young's modulus of modified fibrin hydrogels was evaluated by AFM to quantitatively measure stiffness. It increased 2.5 times with the addition of 4 mg/mL silica. A similar improvement was achieved with only 0.7 mg/mL chitosan-silica, which highlighted the contribution of hydrophilic chitosan chains to fibrinogen crosslinking. Moreover, these chains avoided the fibroblast growth inhibition onto modified fibrin hydrogels 3D culture observed with silica. In conclusion, 0.7 mg/mL chitosan-silica improved the mechanical stability of fibrin hydrogels with low risks of cytotoxicity. This easy-to-manipulate modified fibrin hydrogel makes it suitable as a wound dressing biomaterial.

Biomimetic hydroxyapate/polydopamine composites with good biocompatibility and efficiency for uncontrolled bleeding

Uncontrolled bleeding is thought to be the most deadly cause of pre-hospital, traffic, and military accidents death. However, the popular commercial hemostats can only realize the hemostasis of mild bleeding. Therefore, we developed polydopamine (PDA) composite materials (PMs), which applied hydroxyapatite as the parent body. The PMs were produced via lyophilization and functionalized with amino, phenol hydroxyls groups, which endowed hydrophobicity to materials. This ensured a high aggregation ability of blood cells to the PMs and they were tested to be as high as 300% compared with the negative control group. The clotting time was shortened to 79.7% compared with the usually used commercial hemostat (Celox) in the test of in vitro hemostasis. Through the results of PT and APTT tests, blood coagulation index test, and the analysis of intracellular Ca²⁺ activation, we further understood the mechanism of the hemostasis of the materials, which explained the low blood loss and quick coagulation time of the PM hemostats in detail. Besides, the low hemolysis and cytotoxicity of the PMs suggested the good biocompatibility of the hemostats, which was further proved by the regular morphology maintained by erythrocytes in the hemolysis tests. The study of nanoscale composites led the research for the methods of hemostasis.

Polysaccharides-modified chitosan as improved and rapid hemostasis foam sponges

Serial hemostatic sponges consisting of polysaccharides-modified chitosan foam sponges were prepared by Schiff base crosslinking reaction between the deacetylated chitosan and oxidized dialdehyde cellulose. Such composite foam sponges were characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy to confirm their morphology and compositions. Then the coagulation process was evaluated in vitro by thrombus elasticity meters. Furthermore, the hemostasis experiments on mouse tail vein and rabbit femoral artery were also performed in vivo. The results strongly indicated that such synergistic cellulose-modified chitosan foam sponges showed comprehensively excellent water-absorbing quality, improved mechanical performance, low hemolysis rates, benign cytotoxicity, good resilience ability after repeated compression, and superior hemostasis capability both in vitro and in vivo. Furthermore, the hemostatic mechanism is via adhering/activating the red blood cell/platelet to form robust blood clots through the endogenous coagulation pathway, which serves as a good candidate for emergency trauma treatment in daily civilian and military hemostasis.

Study on hemostatic effect and mechanism of starch-based nano-microporous particles

The powdered hemostatic particles have broad application prospects in large open wounds, internal organ injuries and penetrating injuries of the body. In this study, nanoscale mescoporous and macroporous silica (MMSN), nanoscale mescoporous and macroporous bioactive glass (MBG), micron-scale cross-linked corn starch porous microspheres (CMS), MMSN@CMS and MBG@CMS starch-based nano-microporous particles were synthesized and their hemostatic effect and hemostatic mechanism were studied. The results showed that comparted with the single particle of CMS, the combination particles MBG@CMS and MMSN@CMS significantly increased the water absorption rate, activated both internal and external coagulation pathways, significantly shortened CBT, as well as the improved hemostatic effects in vitro. The immediately released Ca²⁺ from MBG@CMS in the blood to participate in the coagulation pathway, and MMSN@CMS activated platelets by concentrating blood coagulation factors, might be the main hemostatic mechanisms for the starch-based nano-microporous particles. Furthermore, the hemostatic efficacy of particles, both in the model of tail-amputation and liver injury in SD rats, showed the starch-based nano-microporous particles, especial MBG@CMS, could significantly reduce the weight of blood loss and shorten the bleeding time. Our research work stated that the starch-based nano-microporous particles MBG@CMS might be a hemostasis biomaterial with the potential applications for the emergency bleeding.

Preparation and application of chitosan biomaterials in dentistry

Chitosan is a biodegradable and biocompatible natural polysaccharide that has a wide range of applications in the field of dentistry due to its functional versatility and ease of access. Recent studies find that chitosan and its derivatives can be embedded in materials for dental adhesives, barrier membranes, bone replacement, tissue regeneration, and antimicrobial agent to better manage oral diseases. In this paper, we provide a comprehensive overview on the preparation, applications, and major breakthroughs of chitosan biomaterials. Furthermore, incorporation of chitosan additives for the modification and improvement of dental materials has been discussed in depth to promote more advanced chitosan-related research in the future.

Dual functionalized chitosan based composite hydrogel for haemostatic efficacy and adhesive property

The objective of this study was to devise a dual functionalized chitosan based hydrogel dressing to control haemorrhage/ bleeding. The haemostatic hydrogel was formulated by amalgamation of a definite ratio of quaternized chitosan and phosphorylated chitosan along with tannic acid which acted as adjuvant hemostat and a crosslinker. Additionally, the hydrogel contained poly-Ɛ-lysine to impart the elastic and adhesive properties. The optimized hydrogel exhibited superior haemostatic activity (clotting time, 225 ± 5 s), platelet activation (soluble P-selectin concentration 2098 ± 150.19 ng mL^-1), adhesion strength (almost 3 times higher in comparison to Axiostat), higher fluid absorption (approx. 14 times in 12 h) in addition to better mechanical properties, faster coagulation attributes (Prothrombin time, 12.6 s and activated partial thromboplastin time, 30.1 s) and lower proinflammatory potential (almost 3 times lower Tumor Necrosis Factor- α levels and 45 times lower InterLeukin-6 levels at 48 h against control) over marketed chitosan based dressing (clotting time, 300 ± 25 s). Cytotoxicity studies using L929 fibroblasts cells and in-vivo studies using Wistar rats confirmed that the optimized hydrogel was non-toxic, cytocompatible and biocompatible.

Evaluation Procoagulant Activity and Mechanism of Astragalin

Astragalin, isolated from flowers of Rosa chinensis Jacq., is a kind of flavonoid, with anti-inflammatory, antioxidant, antiviral, analgesic, antibacterial, antiallergic, and antihepatotoxic effects. However, no studieson the procoagulant effect of astragalin have been reported. This study aimed to investigate the procoagulant activity of astragalin and its mechanism. Its procoagulant effect was investigated by activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), and fibrinogen (FIB) in vitro, and a rat model established by heparin sodium was used to evaluate the mechanism for the procoagulant effect in vivo. The results showed that astragalin had good procoagulant effects compared with the control group in vitro. Compared with the model group in vivo, astragalin could shorten the coagulation time and significantly increase the number of platelets. Meanwhile, astragalin could significantly reduce the effectual time of PT and APTT and increase the content of FIB. The contents of 6-keto-PGF1α and eNOS significantly decreased. Astragalin could increase whole blood viscosity (WBV), plasma viscosity (PV), erythrocyte sedimentation rate (ESR) and packedcell volume (PCV). All of the above revealed that astragalin had good procoagulant effects by promoting the intrinsic and extrinsic coagulation system.