Clotting Blood into an Adhesive Gel by Hemostatic Powder Based on Cationic/Anionic Polysaccharides and Laponite.

Hemostatic powder is widely employed for emergency bleeding control due to its ability to conform to irregularly shaped wounds, ease of use, and stable storage. However, current powders exhibit limited tissue adhesion and insufficient support for thrombus formation, making them easily washed away by blood. In this study, a hybrid powder (QAL) was produced by mixing quaternized chitosan (QCS) powder, catechol-modified alginate (Cat-SA) powder, and laponite (Lap) powder. Upon addition of QAL, the blood quickly transformed to a robust and adhesive blood gel. The adhesion strength of the blood gel was up to 31.33 ± 1.56 kPa. When compared with Celox, QAL showed superior performance in promoting hemostasis. Additionally, QAL exhibited effectiveness in eliminating bacteria while also demonstrating outstanding biocompatibility with cells and blood. These favorable properties, including strong coagulation, adhesion to wet tissue, antibacterial activity, biosafety, ease of use, and stable storage, make QAL a promising emergency hemostatic agent.

Coagulating blood into adhesive gel by hybrid powder based on oppositely charged polysaccharide/tannic acid-modified mesoporous bioactive glass.

Hemostatic powder is widely utilized in emergency situations to control bleeding due to its ability to work well on wounds with irregular shapes, ease of application, and long-term stability. However, traditional powder often suffers from limited tissue adhesion and insufficient support for blood clot formation, leaving it susceptible to displacement by the flow of blood. This study introduces a hemostatic powder composed of tannic modified mesoporous bioactive glass (TMBG), cationic quaternized chitosan (QCS), and anionic hyaluronic acid modified with catechol group (HADA). The resulting TMBG/QCS/HADA based hemostatic powder (TMQH) rapidly absorbs plasma, concentrating blood coagulation factors. Simultaneously, the water-soluble QCS and HADA interact to form a 3D network structure, which can be strengthened by crosslinking with TMBG. This network effectively captures clustered blood coagulation factors, leading to a strong and adhesive thrombus that resists disruption from blood flow. TMQH exhibits superior efficacy in promoting hemostasis compared to Celox™ both in rat arterial injuries and non-compressible liver puncture wounds. TMQH demonstrates excellent antibacterial activity, cytocompatibility, and blood compatibility. These outstanding superiorities in blood clotting capability, wet tissue adhesion, antibacterial activity, safety for living organisms, ease of application, and long-term stability, make TMQH highly suitable for emergency hemostasis.

Gluing blood into adhesive gel by oppositely charged polysaccharide dry powder inspired by fibrin fibers coagulation mediator.

Hemostatic powders that adapt to irregularly shaped wounds, allowing for easy application and stable storage, have gained popularity for first-aid hemorrhage control. However, traditional powders often provide weak thrombus support and exhibit limited tissue adhesion, making them susceptible to dislodgment by the bloodstream. Inspired by fibrin fibers coagulation mediator, we have developed a bi-component hemostatic powder composed of positively charged quaternized chitosan (QCS) and negatively charged catechol-modified alginate (Cat-SA). Upon application to the wound, the bi-component powders (QCS/Cat-SA) rapidly absorb plasma and dissolve into chains. These chains interact with each other to form a network, which can effectively bind and entraps clustered red blood cells and platelets, ultimately leading to the creation of a durable and robust thrombus. Significantly, these interconnected polymers adhere to the injury site, offering protection against thrombus disruption caused by the bloodstream. Benefiting from these synthetic properties, QCS/Cat-SA demonstrates superior hemostatic performance compared to commercial hemostatic powders like Celox™ in both arterial injuries and non-compressible liver puncture wounds. Importantly, QCS/Cat-SA exhibits excellent antibacterial activity, cytocompatibility, and hemocompatibility. These advantages of QCS/Cat-SA, including strong blood clotting, wet tissue adherence, antibacterial activity, biosafety, ease of use, and stable storage, make it a promising hemostatic agent for emergency situations.

Ferried Albumin-Inspired Bioadhesive With Dynamic Interfacial Bonds for Emergency Rescue.

Emergency prehospital wound closure and hemorrhage control are the first priorities for life-saving. Majority of bioadhesives form bonds with tissues through irreversible cross-linking, and the remobilization of misalignment may cause severe secondary damage to tissues. Therefore, developing an adhesive that can quickly and tolerably adhere to traumatized dynamic tissue or organ surfaces in emergency situations is a major challenge. Inspired by the structure of human serum albumin (HSA), a branched polymer with multitentacled sulfhydryl is synthesized, then, an instant and fault-tolerant tough wet-tissue adhesion (IFA) hydrogel is prepared. Adhesive application time is just 5 s (interfacial toughness of ≈580 J m-2), and favorable tissue-adhesion is maintained after ten cycles. IFA hydrogel shows unchangeable adhesive performance after 1 month of storage based on the internal oxidation-reduction mechanism. It not only can efficiently seal various organs but also achieves effective hemostasis in models of the rat femoral artery and rabbit-ear artery. This work also proposes an effective strategy for controllable adhesion, enabling the production of asymmetric adhesives with on-demand detachment. Importantly, IFA hydrogel has sound antioxidation, antibacterial property, hemocompatibility, and cytocompatibility. Hence, the HSA-inspired bioadhesive emerges as a promising first-aid supply for human-machine interface-based health management and non-invasive wound closure.

Cohering Plasma into Adhesive Gel by Natural Biopolymer-Nanoparticle Hybrid Powder for Efficient Hemostasis and Wound Healing.

Hemostatic powder is commonly used in emergency bleeding control due to its suitability for irregularly shaped wounds, ease of use, and stable storage. However, traditional powder often has limited tissue adhesion and weak thrombus support, which makes it vulnerable to displacement by blood flow. Herein, we have developed a tricomponent hemostatic powder (MQS) composed of mesoporous bioactive glass nanoparticle (MBG), positively charged quaternized chitosan (QCS), and negatively charged catechol-modified alginate (SADA). Upon application to the wound, MBG with its high specific surface area quickly absorbs plasma, concentrating the blood coagulation factor. Simultaneously, the water-soluble QCS and SADA interact with each other and form a net, which can be further cross-linked by MBG. This network efficiently binds and entraps clustered blood coagulation factors, ultimately resulting in the formation of a durable and robust thrombus. Furthermore, the formed net adheres to the injury site, offering protection against thrombus disruption caused by the bloodstream. Benefiting from the synergistic effect of these three components, MQS demonstrates superior hemostatic performance compared to commercial hemostatic powders like Celox in both arterial injuries and noncompressible liver puncture wounds. Furthermore, MQS can effectively accelerate wound healing. In addition, MQS exhibits excellent antibacterial activity, cytocompatibility, and hemocompatibility. These advantages of MQS, including strong blood clotting, wet tissue adherence, antibacterial activity, wound healing ability, biosafety, ease of use, and stable storage, make it a promising hemostatic agent for emergency situations.

PAA-PU Janus Hydrogels Stabilized by Janus Particles and its Interfacial Performance During Hemostatic Processing.

Hydrogel is a very promising dressing for hemostasis and wound healing due to its good adhesion and long-term moist environment. However, secondary injury caused by tissue adhesion due to homogeneous hydrogel cannot be ignored. The obvious interface existing in Janus hydrogel will weaken its asymmetric function. Here, a hierarchical adhesive polyacrylic acid-polyurushiol water-oil Janus hydrogel (JPs@PAA-PU) without adhesive layer is fabricated by one-pot method in the stabilization of polystyrene@silica-siliver Janus particles (JPs). The morphological structure, mechanical properties, anisotropic chemical composition, and adhesion performance, in vivo, and in vitro hemostatic properties of Janus hydrogel are investigated. Result shows that the obtained Janus hydrogel possesses obvious compartmentalization in microstructure, functional groups, and chemical elements. Janus hydrogel is provided with asymmetric interfacial toughness with top 52.45 ± 2.29 Kpa and bottom 7.04 ± 0.88 Kpa on porcine liver. The adhesion properties of PAA side to tissue, red blood cells and platelets, promoting effect of PU side on coagulation cascade reaction and its physical battier endow Janus hydrogel with shorter hemostatic time and less blood loss than control group. It also exhibits excellent antibacterial effects against Escherichia coli and Staphylococcus aureus (>90%). Janus hydrogel possesses biosafety, providing safety guarantee for clinical applications in the future.

Chitosan based Janus cryogel with anisotropic wettability, antibacterial activity, and rapid shape memory for effective hemostasis.

Excessive bleeding and bacterial infection leading to death is a major concern worldwide, particularly in cases of deep and narrow noncompressible hemorrhage. Herein, a novel Janus cryogel with anisotropic surface wettability, antibacterial activity, and rapid shape recovery was designed by constructing a hydrophilic porous cryogel using chitosan (CS), acacia gum (AG), and quaternized mesoporous bioglass (QMBG), with subsequent surface hydrophobic modification using octadecanol. The asymmetric hydrophobic surface modification of octadecanal endowed OCAQ with outstanding antiblood and antibacterial permeability, effectively preventing blood outflow and the invasion of bacteria to the wound. The hydrophilic parts with interconnected macroporous structure give the cryogel with ultra-high water uptake (5167 ± 182 %) and rapid water-trigged shape recover ability (≈2.1 s). The presence of active CS, AG, and QMBG in cryogel contributes to its exceptional blood clotting ability. Janus cryogel presents outstanding hemostatic performance (0.14 ± 0.03 g) in rat's liver injury model. Moreover, Janus cryogel exhibits excellent antibacterial properties due to the combination of its hydrophobic surface and antimicrobial quaternary amine groups. Meanwhile, the Janus cryogel has favorable hemocompatibility and biocompatibility. A Therefore, the Janus cryogel will become a candidate with great potential for clinical application of noncompressible wound as a multifunctional dressing.

Light-oriented 3D printing of liquid crystal/photocurable resins and in-situ enhancement of mechanical performance.

Additive manufacturing technology has significantly impacted contemporary industries due to its ability to generate intricate computer-designed geometries. However, 3D-printed polymer parts often possess limited application potential, primarily because of their weak mechanical attributes. To overcome this drawback, this study formulates liquid crystal/photocurable resins suitable for the stereolithography technique by integrating 4'-pentyl-4-cyanobiphenyl with a photosensitive acrylic resin. This study demonstrates that stereolithography facilitates the precise modulation of the existing liquid crystal morphology within the resin. Furthermore, the orientation of the liquid crystal governs the oriented polymerization of monomers or prepolymers bearing acrylate groups. The products of this 3D printing approach manifest anisotropic behavior. Remarkably, when utilizing liquid crystal/photocurable resins, the resulting 3D-printed objects are approximately twice as robust as those created using commercial resins in terms of their tensile, flexural, and impact properties. This pioneering approach holds promise for realizing autonomously designed structures that remain elusive with present additive manufacturing techniques.

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.

Neurocognitive deficits and sequelae following severe hand, foot, and mouth disease from 2009 to 2017, in JiangSu Province, China: a long-term follow-up study.

BACKGROUND: The aim of this study was to evaluate the long-term sequelae and cognitive profiles resulting from severe hand, foot, and mouth disease (HFMD) with central nervous system (CNS) involvement. METHODS: 294 HFMD cases were included in a retrospective follow-up study. Physical examinations were conducted. The Chinese Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) was used to assess intelligence. RESULTS: 58 mild HFMD cases and 99 severe HFMD cases with mild CNS involvement did not present any neurological sequelae. In comparison, the sequelae incidence for severe HFMD with more severe CNS complications was 50.0%. The proportion of full-scale intelligence quotient (FSIQ) impairment was 45.0%. In the 2:6-3:11 age group, severe HFMD with more severe CNS complications and lower maternal education level were risk factors for verbal comprehension disorder. Urban-rural residence and lower paternal education level were risk factors for FSIQ disorder. Furthermore, in the 4:0-6:11 age group, severe HFMD with more severe CNS complication was a risk factor for visual spatial disorder and fluid reasoning disorder. Lower paternal education level was a risk factor for FSIQ disorder. CONCLUSION: Early assessment and intervention among severe HFMD patients with more severe CNS involvement at a very young age will prove beneficial for their future performance.

Superelastic, Antifreezing, Antidrying, and Conductive Organohydrogels for Wearable Strain Sensors.

Sensors based on conductive hydrogels have received extensive attention in various fields, such as artificial intelligence, electronic skin, and health monitoring. However, the poor resilience and fatigue resistance, icing, and water loss of traditional hydrogels greatly limit their application. Herein, an ionic conductive organohydrogel (PAC-Zn) was prepared for the first time by copolymerization of cardanol and acrylic acid in water/1,3-butanediol as a binary solvent system. A very small amount of cardanol (1% cardanol of total monomers) could not only significantly improve the tensile strength (∼4 times) and toughness (∼3 times) of PAA but also improve its extensibility. Due to the presence of 1,3-butanediol, PAC-Zn showed outstanding tolerance for freezing (-45 °C) and drying (over 85% moisture retention after 15 days of storage in a 37 °C oven). Compared with ethylene glycol and glycerol as antifreeze agents used in organohydrogels, the addition of 1,3-butanediol endowed the organohydrogel with not only similar frost resistance but also better mechanical performance. Besides, PAC-Zn exhibited fast resilience (almost no hysteresis loop) and excellent antifatigue ability. More importantly, a PAC-Zn organohydrogel-based sensor could detect human motion in real time (wrist, elbow, finger, and knee joints), revealing its fast response, good sensitivity, and stable electromechanical repeatability. In conclusion, the multifunctional PAC-Zn organohydrogel is expected to become a potential and promising candidate in the field of strain sensors under a broad range of environmental temperatures.

Adhesive, self-healing, conductive Janus gel with oil-water responsiveness.

The anisotropic Janus gel shows more diverse characteristic and responsiveness due to its asymmetric chemical structure. Herein, the water/oil PDA-PAA/PBMA-PEHMA Janus gel was prepared by one-step polymerization of incompatible monomers. In this Janus gel, PDA-PAA layer possesses good adhesion effect and self-healing property attributing to the chemical bonds and the hydrogen bonds among DA, AA, or each other, and the π-π stacking of DA. The IPN structure of the water phase and the oil phase makes Janus gel have good mechanical properties. The above chemical and physical effects dissipate a large amount of energy when PDA-PAA/PBMA-PEHMA Janus gel is subjected to external forces, so it has excellent fatigue resistance. The hydrophilic PDA-PAA side and the lipophilic PBMA-PEHMA side show different swelling responses in the oil-water medium. The internal stress difference caused by this different swelling makes the Janus gel show curl toward different directions in different media. Then, conductivity media of NaCl added in PDA-PAA layer endows Janus gel with anisotropic conductivity. It is possible to judge the hydrophilic and hydrophobic properties of solution by monitoring the current change of conductive Janus gel. Conductive Janus gel can also be used to monitor human body motion and micro motion. This conductive/insulating Janus gel is suitable for flexible sensor used in harsh environment.

Rapid hemostasis accompanied by antibacterial action of calcium crosslinking tannic acid-coated mesoporous silica/silver Janus nanoparticles.

It is important to control bleeding and prevent bacterial infection for the wound people. The effective way is to fabricate an asymmetric Janus matrial for realizing rapid hemostasis and promoting wound healing. Herein, mesoporous silica nanoparticles (MSN) modified by tannic acid (TA), silver nanoparticles, and calcium ions (Ca-TA-MSN@Ag) with Janus structure were prepared via redox and coordination reactions. These anisotropic snowman-like particles possess obvious chemical compartition, in which silver nanoparticles are embedding in large MSN body. During blood coagulation, TA with catechol structure acts as a vasoconstrictor. Then, Ca-TA-MSN@Ag with high specific surface area (510.62 m2·g-1) and large pore volume (0.48 m3·g-1) induces red blood cell aggregation to form three-dimensional network structure with fibrin. Additionally, calcium ions as clotting factor IV and negative charge of Ca-TA-MSN@Ag accelerate coagulation cascade reaction. These three synergistic effects on animal model showed that hemostatic time of Ca-TA-MSN@Ag was shortened by nearly 50% compared to that of MSN. Moreover, Ca-TA-MSN@Ag possessed good blood compatibility, biocompatibility and antibacterial activity (~99%) against E. coli and S. aureus. The anisotropic Janus particles of Ca-TA-MSN@Ag with hemostatic performance and antibacterial activity will be a promising biomaterial for designing wound dressings in clinical application.

Preparation of Mesoporous Silica Nanoparticles Modified by Urushiol and Their Adsorption on Malachite Green.

The presence of malachite green dye in wastewater has a great negative impact on the environment. At present, industrial wastewater is treated using adsorption, electrolysis and membrane separation, among which the adsorption method is the most widely used wastewater treatment. In this study mesoporous silica nanoparticles (MSNs) were prepared using the sol-gel method and modified with the natural polymer urushiol (U) to obtain MSN@Us, which have a core-shell structure. This is the first use of urushiol in dye adsorption. The structures and chemical properties of the MSNs and MSN@Us were characterized. The adsorption of malachite green by the MSNs and MSN@Us showed that the adsorption rate of MSN@Us was higher than that of MSNs, with an adsorption rate greater than 90%. This study provides a new research direction for the use of urushiol in the treatment of contaminated wastewater.

Click-Grafting of Cardanol onto Mesoporous Silica/Silver Janus Particles for Enhanced Hemostatic and Antibacterial Performance.

Janus particles with obvious chemical compartition can perform their functions independently, so they have attracted much attention in biomedical materials. Herein, a mesoporous silica/silver Janus nanoparticle modified with cardanol (C-MSN@Ag) was designed and synthesized via redox and click chemical reactions and was further evaluated as a highly efficient hemostatic dressing. This Janus structure endowed C-MSN@Ag with both prominent hemostatic and antibacterial performance. The hemostatic time of C-MSN@Ag on rat liver laceration was up to 40% shorter than that of MSN and MSN@Ag because of adhesion of phenolic compounds on the tissue and the blocking effect of the hydrophobic alkyl chains from cardanol. Besides, C-MSN@Ag could promote coagulation by forming a three-dimensional network with fibrin more quickly than MSN and MSN@Ag. Additionally, due to the released silver ions and phenolic hydroxyl groups of cardanol, C-MSN@Ag exhibited a broad-spectrum antibacterial rate (∼99%) against both Escherichia coli and Staphylococcus aureus. C-MSN@Ag also possessed non-cytotoxicity. This work not only provides a way for the fabrication of silica-based Janus hemostatic agents by the atom-economical click reaction but also gives a direction for the application of the sustainable naturally occurring cardanol.

Compatibilization Behavior of Double Spherical TETA-SiO2@PDVB Janus Particles Anchored at the Phase Interface of Acrylic Resin/Epoxy Resin (AR/EP) Polymer Blends.

The inorganic particles used as a compatibilizer play a role in crack termination and heat resistance. However, the poor compatibility of inorganic particles and polymer hinders their application. Herein, the double spherical SiO2@PDVB Janus particles (JPs) were modified with triethylenetetramine (TETA), and the obtained anisotropic TETA-SiO2@PDVB JPs were used as the compatibilizer of acrylic resin/epoxy resin (AR/EP) composites. The modification and the compatibilization of TETA-SiO2@PDVB JPs were studied by scanning electron microscopy, X-ray photoelectron spectroscopy, differential scanning calorimetry, and dynamic mechanical analyzer, impact test, tensile test, and so forth. Results show that amino groups grafted onto the SiO2 lobe can react with epoxy groups of EP, which results in the TETA-SiO2 lobe being embedded in the EP phase and the PDVB lobe being pushed toward the AR phase. The TETA-SiO2@PDVB JPs anchored at the interface of AR and EP increase their interfacial adhesion, decrease the domain phase size and distribution of dispersed AR, and improve the compatibility of AR/EP composites. The compatibilization of nanoparticles (NPs) is realized by the cavitation and blunting of different scaled AR phase domain distributions and that of JPs is realized by the strong interfacial force originated by JPs. Moreover, the desorption energy of TETA-SiO2@PDVB JPs is higher than that of SiO2-TETA; so the glass transition temperature (T g) of AR/EP/JP composites is higher than that of AR/EP/NP composites. The strong interfacial adhesion and high desorption energy endow TETA-SiO2@PDVB JPs with a toughening effect and enhancing effect. The impact strength and the tensile strength of AR/EP/TETA-SiO2@PDVB composites are 16.03 kJ/m2 and 63.12 MPa, which are 9.91 kJ/m2 and 16.32 MPa higher than those of AR/EP composites, respectively. JPs used in the thermosetting EP is benefit to its toughening study and the new anisotropic Janus compatibilizer.

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

The powder hemostatic materials are increasingly appreciated because of their long storage time, wide storage temperature, portable property, especially their use both in vivo and epidermis. Mesoporous silica materials attracted more and more attention owing to their favorable biocompatibility and outstanding hemostatic performance, but their hemostatic process was too simple to meet the requirements. Herein, mesoporous silica nanoparticles modified by chitosan and hydrocaffeic acid (MSN@CS-HCA) were developed for rapid and safe hemorrhage control. By tissue adhesion, activating the coagulation cascade, aggregating red blood cells and platelets, MSN@CS-HCA with the porous network exhibited excellent hemostatic effects in both in vivo and in vitro coagulation tests. The hemostatic time of MSN@CS-HCA was 60.3% shorter than that of MSN in femoral artery trauma models of SD rats. Besides, MSN@CS-HCA with good biocompatibility and ability to promote wound healing, could form the network structure with fibrin in the blood, which enhanced the mechanical strength of the blood clot and acted as a physical barrier to prevent blood loss. In conclusion, MSN@CS-HCA will be a potential and prospective hemostatic dressing for the control of hemorrhage in more extensive clinical application future.

Fabrication of porous starch microspheres by electrostatic spray and supercritical CO2 and its hemostatic performance.

Effective control of bleeding is critical to saving lives whether on the battle field or in civilian life. Microporous starch (MS) is a promising hemostat for its extensive sources, huge surface area and good biocompatibility. However, the hemostatic performance of MS is limited because of its complex preparation process and lack of effective component to activate coagulation factors. Herein, porous starch microspheres modified by calcium (Ca-PSM) with dense shell and honeycomb micro-porous core were prepared by electrostatic spray and supercritical CO2 for the first time. The topological morphology of Ca-PSM changed with the increase of Tween-80 content within 0.5%. Ca-PSM possessed excellent water absorbability due to high specific surface area, and what's more, it showed good hemostatic performance because of the synergistic effects of physical adsorption and chemical activation mechanisms. The results of thrombelastograph (TEG) showed that the initial clotting time (R) and coagulation time (R + K) of Ca-PSM-1 were shortened by 47.1%, 53.3% than that of control group. The maximum blood clot strength (MA) of Ca-PSM-1 was also significantly raised. Furthermore, it was noteworthy that Ca-PSM could activate clotting cascade and induce erythrocyte adsorption. In summary, Ca-PSM as a hemostat will be a promising and alternative candidate for clinical application.

Urushiol-functionalized mesoporous silica nanoparticles and their self-assembly into a Janus membrane as a highly efficient hemostatic material.

Quick hemostasis plays a very important role in preventing hemorrhagic shock and death by controlling blood loss from trauma in civil and military accidents. An ideal quick hemostat should have tissue-adhesive functional groups, clotting factor activating components, and a plasma non-permeable hydrophobic layer. Inspired by the adhesive behavior of mussels, a novel efficient hemostat of urushiol-functionalized mesoporous silica nanoparticles (MSN@U) with a core-shell structure was synthesized and their hemostatic performance was evaluated for the first time. MSN@U could form an amphipathic Janus membrane (a hydrophobic layer and a hydrophilic layer in one membrane) by interfacial self-assembly. The morphology and structure of MSN@U were characterized. The results showed that MSN@U possessed a large specific surface area of 448.91 m2 g-1 and a rich porous structure with an average pore diameter of 3.94 nm. The hydrophilic catechol groups and the long hydrophobic alkyl groups of urushiol allowed MSN@U to self-assemble at the blood/air interface. The former made MSN@U tightly adhere onto blood vessel tissue through covalent bonds, while the latter formed a hydrophobic barrier layer which hindered blood from oozing. Meanwhile, MSN@U would accelerate clotting cascade reactions. These three effects made MSN@U a very quick hemostat with a hemostatic time of 22 ± 2 s on a rat liver laceration. Both in vitro and in vivo tests showed that they had a better hemostatic effect and blood compatibility than MSN. Cell viability evaluations indicated that MSN@U had no cytotoxicity. MSN@U will be a safe and promising hemostatic agent for clinical 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.