Hemostatic Application Research Articles

Recombinant human hair keratin proteins for halting bleeding

Keratins derived from human hair have been widely used for tissue engineering. However, some drawbacks relative to the traditional keratins extracts have been found: (a): difficultly controlling the amino acid composition; (b): batch to batch inconsistent quality; and (c): producing complex keratin and keratin-associated proteins (KAPs), which problems have made some studies concerning human hair keratins stagnant, especially in the mechanism studies related to hemostasis of keratins. Herein, a type-I human hair keratin of K37 and a type-II human hair keratin of K81 were heterologously expressed and firstly used for haemostatic application. SDS-PAGE analysis shows that the recombinant keratins had higher purity compared to the extracted keratins. The circular dichroism (CD) spectra of K37 and K81 suggested that the secondary structures were rich in α-helix. In addition, the recombinant keratin proteins could enhance fibrin colt formation at the site of injury and decrease the bleeding time and blood loss in liver puncture and femoral artery injury rat models. This study provides a new strategy for future works involving design and mechanism studies of keratin biomaterials.

Prehospital Application of Hemostatic Agents in Iraq and Afghanistan

Introduction: Hemorrhage is the leading cause of death on the battlefield. Development of chitosan- and kaolin-based hemostatic agents has improved hemorrhage control options. Sparse data exists on the use of these agents in the prehospital, combat setting. We describe recent use of these agents and compare patients receiving hemostatic to the baseline population. Methods: We used a series of emergency department (ED) procedure codes to identify patients within the Department of Defense Trauma Registry (DODTR) from January 2007 to August 2016. We only included patients for whom the DODTR specified the hemostatic agent utilized (chitosan or kaolin). We defined a serious injury by body region as an Abbreviated Injury Score (AIS) of 3 or greater. Results: Our predefined search codes captured 28,222 patients. Of those, 258 (0.9%) patients had documented hemostatic use: 58 chitosan, 201 kaolin, and one subject received both. Patients undergoing hemostatic agent application were more likely to be injured by gunshot wound or explosive. Patients with hemostatic application had higher median composite Injury Severity Scores (10 vs. 9, p < 0.001), and higher AIS for the abdomen, extremity and superficial body regions with higher rates of blood product utilization. Proportions of patients suffering traumatic amputations and undergoing tourniquet application were higher in the hemostatic agent group than the baseline population (11.6% vs. 6.7%, p = 0.002 and 43.4% vs. 13.8%, p < 0.001, respectively). Conclusions: Hemostatic agents were infrequently utilized to manage traumatic hemorrhage during the recent conflicts in Afghanistan and Iraq. Hemostatic agent use was more frequent in casualties with gunshot wounds, traumatic amputations, concomitant tourniquet application, and greater blood product administration.”

Naturally-derived microparticles for hemostatic applications

ABSTRACTThe research area of hemostatic biomaterials is an emerging field attracted lots of interests recently due to the soaring number of traumas. One of the key unmet needs in this area is non-toxic, non-irritating, cost-effective, hemostatic materials which can shorten blood clotting time effectively. Here we used naturally derived starch to prepare two types of new hemostatic microparticles, swellable and microporous starch particles. The hemostatic particles were characterized by optical and scanning electron microscopy and evaluated for their swelling and hemostatic properties. The results of in vitro blood test demonstrated a strong relationship between swelling power and blood clotting index (BCI). Also, the swellable microparticles had dominant ability of water/blood absorption over the microporous particles, accelerating the aggregation of red blood cells, thrombin, platelets and fibrin and other active components on the particle surface and thus achieving better hemostatic effect.

Study of locust bean gum reinforced cyst-chitosan and oxidized dextran based semi-IPN cryogel dressing for hemostatic application

Severe blood loss due to traumatic injuries remains one of the leading causes of death in emergency settings. Chitosan continues to be the candidate material for hemostatic applications due to its inherent hemostatic properties. However, available chitosan-based dressings have been reported to have an acidic odor at the wound site due to the incorporation of acid based solvents for their fabrication and deformation under compression owing to low mechanical strength limiting its usability. In the present study semi-IPN cryogel was fabricated via Schiff's base cross-linking between the polyaldehyde groups of oxidized dextran and thiolated chitosan in presence of locust bean gum (LBG) known for its hydrophilicity. Polymerization at −12 °C yielded macroporous semi-IPN cryogels with an average pore size of 124.57 ± 20.31 μm and 85.46% porosity. The hydrophobicity index of LBG reinforced semi-IPN cryogel was reduced 2.42 times whereas the swelling ratio was increased by 156.08% compare to control cryogel. The increased hydrophilicity and swelling ratio inflated the compressive modulus from 28.1 kPa to 33.85 for LBG reinforced semi-IPN cryogel. The structural stability and constant degradation medium pH were also recorded over a period of 12 weeks. The cryogels demonstrated lower adsorption affinity towards BSA. The cytotoxicity assays (direct, indirect) with 3T3-L1 fibroblast cells confirmed the cytocompatibility of the cryogels. The hemolysis assay showed <5% hemolysis confirming blood compatibility of the fabricated cryogel, while whole blood clotting and platelet adhesion assays confirmed the hemostatic potential of semi-IPN cryogel.

A method for systematically evaluating the hemostatic ability of hydrogels in vitro.

The bursting strength is a key parameter to assess hemostatic ability of tissue sealants. It is associated to mechanical property of the materials, the binding strength of the materials to the tissues as well as the applied conditions of the materials, such as temperature and wound size. Few works have systematically investigated the relationship of the hemostatic ability of hydrogels with the factors listed above. This study introduced a method to systematically investigate the effect of the thickness, covered area and components of hydrogels, and the applied conditions on the bursting strength of hydrogels. The gelatin hydrogel and fibrin glue were used in this study. The method quantitatively investigated the effect of material properties and applied conditions on the bursting strength of materials. It also suggested a minimum dosage of tissue sealant used in both animal study and clinical practice. This study proved that the method we proposed is reliable to assess the bursting strength of materials for the hemostatic application.

In vitro and in vivo evaluation of the duck's feet collagen sponge for hemostatic applications

Recently different hemostatic agents have been developed, but most of them are ineffective in severe bleeding and expensive or cause safety concerns. In this study, we fabricated duck's feet collagen-based porous sponges and investigated its use as a hemostatic agent. We determined the sponge's physical and biological characteristics and compared with Avitene via scanning electron microscope analysis, water-uptake abilities and porosity test, and cytotoxicity assay. The duck's feet collagen/silk sponge showed a larger interconnected porous structure compared to others sponges. The duck's feet collagen/silk sponge also exhibited significantly higher porosity than Avitene. Hemostatic properties of the sponges were evaluated by whole blood clotting and rat femoral artery hemorrhage experiment. The addition of silk to duck's feet collagen showed better blood clotting ability than Avitene in vitro. However, rat femoral artery hemorrhage test showed a similar hemostatic property between the duck's feet collagen-based sponges and Avitene. We suggest that duck's feet collagen-based sponge can be effectively used for hemostatic applications.

Biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers for rapid hemostasis

Efficient and biodegradable hemostatic materials become increasingly important in civilian and military clinical. However, traditional hemostatic materials are difficult to achieve expected effects especially in parenchymal organs with rich vascularity. In facing these challenges, we designed a biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers (CPNFs-Col sponge) for rapid hemostasis. With specific performances, such as rapid water absorption ability, the positive surface rich in amino groups and high specific surface area (952.5m2g−1), the obtained CNPFs-Col sponge with optimized composition could activate the intrinsic pathway of coagulation cascade, induce haemocytes and platelets adherence, promote the blood clotting and achieve hemorrhage control in vitro and in vivo. In addition, the CNPFs-Col sponge can be completely biodegraded in 3 weeks, which is suitable for post-operative treatment and peritoneal adhesion prevention. It can be concluded that the CPNFs-Col sponge would become a promising candidate for clinical hemostatic applications.

627 Multicentre Randomised Controlled Trial Comparing the Efficacy and Safety of Adding Early Hemostatic Powder Application to Endoscopic and Medical Treatment in the Management of Acute Variceal Bleeding in Cirrhotic Patients

627 Multicentre Randomised Controlled Trial Comparing the Efficacy and Safety of Adding Early Hemostatic Powder Application to Endoscopic and Medical Treatment in the Management of Acute Variceal Bleeding in Cirrhotic Patients

Enzymatic Hydrolysis of Silk Fibroin Peptide for Hemorrhage Control

Effective hemorrhage control becomes increasingly significant in today’s military and civilian trauma, while the topical hemostats currently available in market still have various disadvantages. In this study, the silk fibroin peptide (SFP) was prepared through alcalase hydrolysis of silk fibroin. The result of thromboelastographic (TEG) method showed that the SFP can significantly strengthen the coagulation in blood. The results of APTT measurements reflected the acceleration of activation of intrinsic pathway. In the murine hepatic injury model, the blood loss and the bleeding time significantly reduced with the use of SFP as compared with the equal masses of gauze. Based on these results, it can be suggested that the developed SFP has the excellent hemostatic effect, caused no observable tissue damage at the site of application and would be a promising material in clinical hemostatic application.

Isolation, Characterization and Evaluation of Collagen from Jellyfish Rhopilema esculentum Kishinouye for Use in Hemostatic Applications.

Hemostat has been a crucial focus since human body is unable to control massive blood loss, and collagen proves to be an effective hemostat in previous studies. In this study, collagen was isolated from the mesoglea of jellyfish Rhopilema esculentum Kishinouye and its hemostatic property was studied. The yields of acid-soluble collagen (ASC) and pepsin-soluble (PSC) were 0.12% and 0.28% respectively. The SDS-PAGE patterns indicated that the collagen extracted from jellyfish mesoglea was type I collagen. The lyophilized jellyfish collagen sponges were cross-linked with EDC and interconnected networks in the sponges were revealed by scanning electron microscope (SEM). Collagen sponges exhibited higher water absorption rates than medical gauze and EDC/NHS cross-linking method could improve the stability of the collagen sponges. Compared with medical gauze groups, the blood clotting indexes (BCIs) of collagen sponges were significantly decreased (P < 0.05) and the concentration of collagen also had an influence on the hemostatic property (P < 0.05). Collagen sponges had an improved hemostatic ability compared to the gauze control in tail amputation rat models. Hemostatic mechanism studies showed that hemocytes and platelets could adhere and aggregate on the surface of collagen sponge. All properties make jellyfish collagen sponge to be a suitable candidate used as hemostatic material and for wound healing applications.

Chitosan-PVA monodisperse millimeter-sized spheres prepared by electrospraying reduce the thromboembolic risk in hemorrhage control.

Uncontrolled hemorrhage is the main cause of death in many situations. Substantial efforts have been focused on developing more efficient hemostatic agents. Meanwhile, their safety is also critical for their application. Chitosan is an attractive natural polymer and has been widely investigated for hemostatic application. This study sought to incorporate poly(vinyl alcohol) (PVA) components and fabricate them into monodisperse millimeter-sized spheres to improve efficiency and safety. Chitosan-PVA spheres were fabricated by electrospraying and ionotropic gelation. The millimeter-sized spheres were obtained by adjusting the electrospraying parameters, including applied voltage, working distance, feed rate, polymer solution and component content. The morphology, chemical structure and thermostability of the spheres were characterized by variable pressure scanning electron microscopy (VP-SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). These spheres showed narrow size distribution and good biocompatibility. The hemostatic effect was evaluated both in vitro and in vivo using a blood coagulation timing experiment and a rat liver hemorrhaging model, and chitosan50-PVA50 spheres showed the best effect. PVA contributed to the high swelling degree of the spheres and the enhanced hemostatic effect. These spheres also significantly reduced thromboembolus formation in controlling femoral artery bleeding compared with chitosan powder, providing an efficient and safe hemostasis agent.

The efficacy of a novel saline/bipolar radiofrequency energy instrument for arresting ongoing solid and non-solid organ hemorrhage in a swine model

IntroductionOngoing hemorrhage is often life threatening and can be challenging to stop in critically injured patients. Traditional techniques for addressing this issue include high voltage cautery (Bovie), topical hemostatic application, and the delivery of ignited argon gas. The goal of this study was to evaluate the efficacy of a novel energy device for arresting ongoing bleeding from both solid and non-solid organs within a swine model. MethodsA novel instrument utilizing bipolar radiofrequency (RF) energy which acts to ignite/boil dripping saline from a small hand piece was employed to arrest ongoing hemorrhage from an escalating series of injuries in large male swine. Liver, spleen, kidney, lung, heart, inferior vena cava and abdominal wall targets were evaluated and digitally recorded. Methodology was descriptive. ResultsFour large male swine received escalating injuries to their liver, spleen, kidney, lung, heart, inferior vena cava and abdominal wall. Injury patterns included a variety of surface decapsulation, superficial lacerations, deep lacerations, “through and through” missiles and complete transections. Application of the bipolar/RF instrument to sites of ongoing hemorrhage was successful in 97% of all scenarios. Depth of tissue penetration via microscopic evaluation ranged from 1.1mm to 3.0mm depending on the target organ composition. No air leaks were observed following application to the bleeding lung. Surgeon reported ‘ease of use’ score was high (4.8/5). ConclusionThis energy technology is successful in arresting ongoing hemorrhage from varying intensities of traumatic injuries to the liver, spleen, kidney, abdominal wall, lung and heart in the swine model. Additional testing is required before advocating its use on any thoracic organs.

Sealing of the hepatic resection area using hemostat devices does not improve results of adequate surgery

In hepatic resections, there has been a high quality demand. The aim of this systematic clinical, prospective, unblinded unicenter observational study with two arms in an unselected patient cohort was to investigate whether hemostat device can significantly improve outcome in resective liver surgery, in particular, in high risk patients. All consecutive patients (mean age, 60.5 [range, 17 - 96] years) who underwent hepatic resection (ntotal = 770) were prospectively documented in a computer-based registry at a university hospital (tertiary center) over a time period of 10years and retrospectively evaluated specifically with regard to the use (-/+; in daily practice and intraoperative decision-making) of hemostat device (Tissucol(®), n = 59/Tachocomb(®), n = 202/combination, n = 55) indicated (among others) by drainage volume, inflammatory parameters and rate of specific complications (nvalidated = 541 [100 %]). Most frequently, (a-)/typical segmental resections were used: n = 192/90 (3-segment resection, only n = 38). 1) For the assignment of patients to the two different groups (-/+ hemostat device), weight loss and type of resection were found as significant factors (trend: ASA, cirrhosis), for the amount of drainage volume, ASA, sex, Karnofsky Performance Scale and also type of resections using independent distributed statistical tests (such as χ(2), U test [Mann/Whitney]; H test [Kruskal-Willis]; correlation coefficient by Spearman) - no impact: smoking, diabetes, BMI, ethanol. 2) Not taking into account these parameters, the use of hemostat device was characterized by an increased drainage volume (negative control <Tissucol = Tachocomb < combination). 3) Using multifactorial analysis of variance, it was found even under correction by the factors with significant impact elucidated in the single test that the application of hemostat device onto the hepatic resection area resulted unexpectedly rather in an increase than adecrease of the drainage volume but 4) under accompanying more pronounced increase of the white blood cell count (leucocytosis). 5) General and specific complications such as postoperative bleeding, biliary fistula and subhepatic abscess were not further lowered in a significant manner using hemostat device. Adequate surgery in the operative management of hepatic resection area cannot further be improved or optimized using hemostat device. In this context, drainage volume may not be considered a sufficient rather an orienting parameter. However, there is an inflammatory response detectable most likely indicated by a(n un-)specific effusion and increase of white blood cell count, which can be interpreted as a) being characteristic for the problematic group of patients, in whom hemostat device was decided to be useful and was finally used in daily prectice, or b) reactive inflammation to foreign material.

Development of feather keratin nanoparticles and investigation of their hemostatic efficacy

Chicken feathers are considered as the major waste in poultry industry, which are mostly constituted of keratin proteins. Development of feather keratin for biomedical application is very attractive for chicken feather recycling. Human hair keratins have been demonstrated the significant hemostatic efficacy in the previous studies, but there are few reports of feather keratin for the hemostatic application. Here, the chicken feather keratin nanoparticle was developed for use as a hemostatic agent. Keratin was extracted from chicken feather in the present study, and a modified ultrasonic dispersion method was used to prepare keratin nanoparticles. The characterizations of feather keratin extracts and nanoparticles were investigated, including electrophoretic separation, amino acid composition, particle size, zeta potential, morphology, chemical structure and crystal form. Additionally, the hemostatic efficacy in vitro and in vivo of keratin nanoparticles were also studied. The results of hemostatic tests showed that the bleeding time and blood loss in tail amputation and liver scratch rat models can be significantly decreased after application of feather keratin nanoparticles, which demonstrated the potential application of feather keratin nanoparticles for hemostasis.

Use of a novel saline/bipolar radiofrequency energy instrument as an adjunct for arresting ongoing solid organ surface and laceration bleeding in critically injured patients

IntroductionSolid organ (liver, spleen and kidney) haemorrhage is often life threatening and can be difficult to stop in critically ill patients. Traditional techniques for arresting this ongoing bleeding include coagulation by high voltage cautery (Bovie), topical haemostatic application, and the delivery of ignited argon gas. The goal of this study was to evaluate the efficacy of a new energy device for arresting persistent solid organ haemorrhage. Patients and methodsA novel instrument utilizing bipolar radiofrequency (RF) energy which acts to ignite/boil dripping saline from a simple hand piece was employed to arrest ongoing bleeding from solid organ injuries at 2 high volume, level 1 trauma centres. This instrument is extrapolated from experience within elective hepatic resections. Standard statistics were employed (p<0.05=significant). ResultsFrom January 2013 to January 2015, 36 severely injured patients (mean injury severity score=31; blunt mechanisms=32/36 (89%)) underwent use of this new saline/RF energy instrument to arrest ongoing haemorrhage from the liver (29), spleen (5) and kidney (2). Of these patients, 25 received instrument use during an initial laparotomy, while 11 patients underwent use following removal of sponges during a return laparotomy after an initial damage control procedure. Success in arresting ongoing haemorrhage was 97% (35/36) in these highly selected cases. The surgeons reported an ‘ease of use’ score of 4.9 out of 5. No postoperative complications (including delayed haemorrhage) were noted as a direct result of the energy instrument. ConclusionsThis simple saline/RF energy instrument has the potential to arrest ongoing solid organ surface/capsular bleeding, as well as moderate haemorrhage associated with deep lacerations.

Development and assessment of kerateine nanoparticles for use as a hemostatic agent

Uncontrolled bleeding frequently occurs in some emergencies which can result in severe injury and even death. Keratin hydrogel has been found that it had good ahemostatic efficacy in the previous studies. However, an ideal hemostatic agent should not require mixing or preparation in advance, and hydrogel is not easy to store and carry. In the present study, the kerateine was firstly extracted from human hair, and then was prepared nanoparticles by a modified emulsion diffusion method. The synthesized nanoparticles showed spherical morphology with an average diameter of approximately 200nm. The results of Fourier transform infrared spectroscopy and X-ray diffraction indicated that the chemical structure of kerateine did not change but the crystal form may be transformed in the nanoparticles. In addition, kerateine nanoparticles displayed a faster clotting time in vitro study than the kerateine extracts. Furthermore, kerateine nanoparticles significantly reduced the blood loss and coagulation time in the liver puncture and tail amputation in rat models. Our results indicated that kerateine nanoparticles could quickly form a high viscosity gel onto the wound and accelerate the blood coagulation based on their high specific surface area. Therefore, kerateine nanoparticles have great potential for hemostatic application.

Preparation and hemostatic property of low molecular weight silk fibroin

Effective hemorrhage control becomes increasingly significant in today’s military and civilian trauma, while the topical hemostats currently available in market still have various disadvantages. In this study, three low molecular weight silk fibroins (LMSF) were prepared through hydrolysis of silk fibroin in a ternary solvent system of CaCl2/H2O/EtOH solution at different hydrolysis temperatures. Fourier transform infrared spectroscopy analysis showed that the content of β sheet structure in the LMSF decreased with the increase in hydrolysis temperature. The results of thromboelastographic and activated partial thromboplastin time methods showed that the LMSF hydrolyzed at 50 °C can significantly strengthen the coagulation in blood and activate the intrinsic pathway of coagulation cascade. In the murine hepatic injury model, the LMSF hydrolyzed at 50 °C can promote the blood clotting and decrease the blood loss and bleeding time. Based on these results, it can be suggested that the developed LMSF has the excellent hemostatic effect and may be a promising material in clinical hemostatic application.

In vitro evaluation of thrombogenicity effect of gallium-containing mesoporous bioactive glass

Event Abstract Back to Event In vitro evaluation of thrombogenicity effect of gallium-containing mesoporous bioactive glass Sara Pourshahrestani1, Ehsan Zeimaran1, Nahrizul A. Kadri1 and Mark R. Towler1, 2 1 University of Malaya, Department of Biomedical Engineering, Malaysia 2 Ryerson University, Department of Mechanical & Industrial Engineering, Canada Introduction: Inorganic hemostats have demonstrated effectiveness in staunching bleed out[1]. Mesopororus bioglasses (MBGs) are promising candidate for hemorrhage control due to their high specific surface area, pore volume and pore size[2]. Gallium nitrate has proven efficacy in stimulation of the early stages of hemostasis (either coagulation, platelet activation, or thrombus formation)[3]. In this paper, MBGs containing three different concentrations of Ga2O3 (1, 2 & 3 mol %) were synthesized and the effect of Ga3+ addition to the MBG framework on in vitro thrombogenicity of MBG was evaluated. Methods: Three MBGs (80-x) %SiO2–15%CaO–5%P2O5–xGa2O3 doped with different content of Ga2O3 were synthesized via evaporation-induced self-assembly (EISA) process by using Pluronic P123 as a mesostructure former. Briefly, Pluronic P123, tetraethyl orthosilicate (TEOS), Ca(NO3)2.4H2O, triethyl phosphate (TEP), Ga(NO3)3. X H2O and 0.5 M HNO3 were dissolved in ethanol and then stirred overnight and the sol underwent the EISA process for one week. The dried gels were calcinated at 600°C for 5 h. The textural properties of the prepared materials were determined by N2 adsorption/desorption analyses using a Micrometrics ASAP 2020 instrument. The surface area and pore size distribution were determined by applying the Brunauer–Emmett–Teller (BET) and the Barret–Joyner–Halenda (BJH) methods respectively. To test the in vitro thrombotic effect, the materials were incubated with citrated human blood for 15, 30 and 60 min at 37 °C. The degree of thrombogenicity (DT) of the materials was defined as follows: DT = [(Wt-W0)/W0] × 100%, where W0 and Wt are the weights of the samples before and after incubation with blood, respectively. Field-emission scanning electron (FESEM: Quanta™ 250 FEG—FEI, USA) micrographs were also obtained to observe the interaction of whole blood with the Ga-MBG materials. Results and Discussion: Table 1 demonstrates the BET, pore volume and pore size of MBG and Ga-MBG samples. Notably, the surface area and pore volume of the 1%Ga-MBG were found to be higher than those of other samples. As can be seen in Figure 1a, with increasing incubation time, the thrombus formation on the surface of 1%Ga-MBG increased greatly with respect to MBG. FESEM images shows that in comparison to MBG (Figure. 1b), more red blood cells (RBCs) were aggregated on 1%Ga-MBG surface (Figure. 1c) and coalesced into an erythrocyte plug surrounded by a mesh of cross-linked fibrin strands. The thrombogenic activity of the 1%Ga-MBG could be explained as owing to the synergy of both its higher specific surface area and pore volume that provide more space for trapping blood plasma components combined with the presence of Ga3+ which may lead to polymerization of fibrinogen into strong fibrin clots and subsequent stimulation of blood coagulation cascade. The abundant presence of silanol groups on 1%Ga-MBG surface that bind with the phosphatidyl choline-rich RBC membrane, can be also involved in higher thrombogenic potential of 1%Ga-MBG[4]. Conclusion: This study suggests that the MBG with lowest amount of Ga2O3 could be considered as a promising candidate for hemostatic application as showed great thrombotic effect in vitro. However, there is a growing need to investigate the capability of the materials to produce a stable clot in vivo. This research is supported by a High Impact Research MoE Grant (UM.C/625/1/HIR/MoE/ENG/58) from the Ministry of Higher Education Malaysia and University of Malaya Research Grant (UMRG, RG156-12AET).

Development of gelatin/zein fibrous membranes for hemostatic application

Microporous structures are usually designed for hemostatic agents to dehydrate blood and thus accelerate the natural clotting process. We have developed gelatin-based fibrous membranes by co-electrospinning with a hydrophobic protein, zein, for hemostatic dressings. The hybrid gelatin/zein fibers showed structural integrity upon introduction into an aqueous medium without the subsequent crosslinking of the protein components. Fibrous membranes with different gelatin/zein ratios were characterized by blood absorption, whole blood clotting, and coagulation activity in vitro and hemostatic efficiency in vivo. The results indicated that both blood and simulated body fluid uptake were increased as zein content of hybrid fibers decreased, in correspondence to the increase of hydrophilicity of the membranes. Coagulation activity tests showed that both components did not activate coagulation at all, indicating that the gelatin/zein fibrous membrane provided a physical matrix for clotting to be initiated. Adequate hemostatic efficacy was observed after applying gelatin/zein fibrous membranes to bleeding sites on the auricular vein, middle auricular artery, and liver of rabbits. In different hemorrhage models, fibrous membranes with a gelatin/zein ratio of 3/1 showed the least bleeding time and blood loss among the other membranes as well as control (gelatin sponge). Moreover, the total blood loss in the liver injury using the membrane (50.7 mg ± 3.8 mg) was significantly less than that of the control (182.5 mg ± 40.3 mg). Overall results demonstrated that gelatin/zein fibrous membranes with fibrous structure and moderate fluid absorption ability showed rapid hemostasis and limited blood loss, which could be of great benefit for hemostatic applications.

The efficient hemostatic effect of Antarctic krill chitosan is related to its hydration property

Antarctic krill chitosan (A-Chitosan) was first evaluated in its hemostatic effect in this study. The prepared A-Chitosan powder showed low level of crystallinity and significantly high water binding capacity as 1293% (w/w). By mice tail amputation model and blood coagulation timing experiment, it is showed that this chitosan accelerated the tail hemostasis by 55% and shortened the blood clotting time by 38%. This efficacy was better than two other commercial chitosans investigated and was corresponding to their water binding capacities. Through examining the effect of chitosan on blood components, it could be found that platelets adhesion was mainly affected by the water binding capacity, and red blood cells aggregation was dependent on their deacetylation degree. The physicochemical properties resulted in better hydration property of chitosan would improve its hemostatic effect. These results suggested that Antarctic krill chitosan is a good candidate for hemostatic application.