A special report on the chitosan-based hemostatic dressing: experience in current combat operations

Evaluation of the safety and efficacy of the Axiostat® dressing device to achieve radial artery access hemostasis: The R3A study

BACKGROUND

Radial access is the default approach in interventional cardiology. The Axiostat® surgical hemostatic dressing, using chitosan as its active component, has demonstrated potential in accelerating blood clotting. This study aims to assess the efficacy and the safety of the Axiostat® dressing in achieving hemostasis in patients undergoing transradial coronary angioplasty (TRCA).

METHODS

This prospective, single-center observational study, conducted in 2022, enrolled consecutive patients undergoing TRCA, with a target of 150 participants. The primary outcome was the success rate of radial artery hemostasis at 120 min, without bleeding necessitating immediate re-compression. The secondary outcome included Axiostat® performance at 24 h and 30 days Postprocedure.

RESULTS

The study was terminated prematurely for ethical and patient safety reasons, after inclusion of 41 consecutive TRCA patients due to an unexpectedly high radial artery thrombosis rate (19.5%, n = 8/41) observed 24 h Postprocedure. The success rate of radial hemostasis with the Axiostat® dressing was 78.0%. Procedural details and patient characteristics were comparable between successful Axiostat® removal and device failure cases.

CONCLUSION

The use of the Axiostat® dressing to achieve hemostasis after TRCA is effective but is associated with an unexpectedly high incidence of radial thrombosis. Our results should encourage caution in the future evaluation and use of this device for radial artery compression following TRCA.

Nanofibrous composite from chitosan-casein polyelectrolyte complex for rapid hemostasis in rat models in vivo

Bleeding causes ∼5.8 million deaths globally; half of the patients die if rapid hemostasis is not achieved. Here, we report a chitosan-casein (CC)-based nanofibrous polyelectrolyte complex (PEC) that could clot blood within 10 s in the rat femoral artery model in vivo. The nanofiber formation by self-assembly was also optimized for process parameters (concentration, mixing ratio, pH, and ultrasonication). Results showed that increasing the concentration of chitosan from 10 % to 90 % in the formulation increased the productivity (r = 0.99) of PECs but led to increased blood clotting time (r = 0.90) due to an increase in zeta potential (r = 0.98), fiber diameter (r = 0.93), and decreased surface porosity (r = -0.99), absorption capacity (r = -0.99). The pH also influenced the zeta potential of PEC, with an optimized pH of 8.0 ± 0.1 yielding clear nanofibers. Sonication improved the segregation of nanofibers by promoting water removal. The optimized PECs containing chitosan and casein in the ratio of 30:70 (CC30) at a pH of 8.0 and dehydration under sonication could clot the blood within 9 ± 2 s in vitro and 9 ± 2 s in rat femoral artery puncture model. The CC30 formulation did not cause any irritation or corrosion on rat skin. Histopathology and immunohistochemistry of various organs showed that CC30 was biocompatible and non-immunogenic under in vivo conditions.

Advances in nanotechnology for improving the targeted delivery and activity of amphotericin B (2011-2023): a systematic review

Amphotericin B (AmB) is a broad-spectrum therapeutic and effective drug, but it has serious side effects of toxicity and solubility. Therefore, reducing its toxicity should be considered in therapeutic applications. Nanotechnology has paved the way to improve drug delivery systems and reduce toxicity. The present study, for the first time, comprehensively reviews the studies from 2011 to 2023 on reducing the in vitro toxicity of AmB. The findings showed that loading AmB with micellar structures, nanostructured lipid carriers, liposomes, emulsions, poly lactide-co-glycolide acid, chitosan, dendrimers, and other polymeric nanoparticles increases the biocompatibility and efficacy of the drug and significantly reduces toxicity. In addition, modified carbon nanoparticles (including graphene, carbon nanotubes, and carbon dots) with positively charged amine groups, PEI, and other components showed favorable drug delivery properties. Uncoated and coated magnetic nanoparticles and silver NPs-AmB composites had less cytotoxicity and more antifungal activity than free AmB. Citrate-reduced GNPs and lipoic acid-functionalized GNPs were also effective nanocarriers to reduce AmB cytotoxicity and improve anti-leishmania efficacy. In addition, zinc oxide-NPs and PEGylated zinc oxide-NPs showed favorable antifungal activity and negligible toxicity. According to a review study, carbon-based nanoparticles, metal nanoparticles, and especially polymer nanoparticles caused some reduction in the toxicity and improved solubility of AmB in water. Overall, considering the discussed nanocarriers, further research on the application of nanotechnology as a cost-effective candidate to improve the efficiency and reduce the cytotoxicity of AmB is recommended.

Chitosan-based dressing for management of palatal donor site: A randomized clinical trial

AIMS

This study aimed to evaluate the effectiveness of a chitosan-based dressing (CD) in achieving early wound healing and hemostasis at palatal donor sites in patients undergoing free gingival graft (FGG) surgery.

METHODS

Thirty-two patients requiring FGG were treated in this randomized controlled clinical trial. Complete epithelialization (CE) and color match (CM) at donor sites were assessed by a blinded examiner on postoperative days 7, 14, 21, and 28. Donor sites were compressed for 2 min with wet gauze (WG) alone in control group (CG) or WG + CD in test group (TG) immediately after graft harvesting, and immediate bleeding (IB) was recorded (yes/no). Delayed bleeding (DB) (for 1 week), and number of analgesic tablets consumed, and VAS scores for pain (for 2 weeks) were recorded by patient every day.

RESULTS

Twenty-eight patients (14 in each group) were included in final analysis. The prevalence of CE (at weeks 2 and 3) and VAS scores for CM scores were higher in TG but the intergroup differences were statistically significant only for CM (at week 4). Number of patients exhibiting IB and DB was significantly fewer in the TG (p < .05). Although average pain scores and analgesic consumption were higher in TG up to 5 days, differences between two groups were not statistically significant at any time point.

CONCLUSION

Our data suggests that the application of CD increased re-epithelialization and accelerated wound healing process, although it did not reach statistical significance. Moreover, CD was found to significantly reduce bleeding complications, but it did not decrease the pain levels.

Preparation and assessment of agar/TEMPO-oxidized bacterial cellulose cryogels for hemostatic applications

In this work, we have demonstrated agar and oxidized bacterial cellulose cryogels as a potential hemostatic dressing material. TEMPO-oxidized bacterial cellulose (OBC) was incorporated into the agar matrix, improving its mechanical and hemostatic properties. The oxidation of bacterial cellulose (BC) was evidenced by chemical characterization studies, confirming the presence of carboxyl groups. The in vitro blood clotting test conducted on agar/OBC composite cryogels demonstrated complete blood clotting within 90 seconds, indicating their excellent hemostatic efficacy. The cryogels exhibited superabsorbent properties with a swelling degree of 4200%, enabling them to absorb large amounts of blood. Moreover, the compressive strength of the composite cryogels was appreciably improved compared to pure agar, resulting in a more stable physical structure. The platelet adhesion test proved the significant ability of the composite cryogels to adhere to and aggregate platelets. Hemocompatibility and cytocompatibility tests have verified the safety of these cryogels for hemostatic applications. Finally, the material exhibited remarkable in vivo hemostatic performance, achieving clotting times of 64 seconds and 35 seconds when tested in the rat tail amputation model and the liver puncture model, respectively. The experiment results were compared with those of commercial hemostat, Axiostat, and Surgispon, affirming the potential of agar/OBC composite cryogel as a hemostatic dressing material.

Solubilization of chitosan in biologically relevant solvents by a low-temperature solvent-exchange method for developing biocompatible chitosan materials

Chitosan has great potential for biomedical applications. However, the intractable solubility of chitosan is a major bottleneck hampering its utilization. In this work, we report a low-temperature solvent-exchange method to solubilize chitosan in biologically relevant solvents (bio-solvents) including water, salines, and cell culture media. Chitosan was firstly dissolved in ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate (EMIM Ac). The chitosan/IL solution was then dialyzed against bio-solvents at 4 °C, during which a solvent exchange process took place. At the end of 24 h dialysis, aqueous chitosan pseudosolutions formed. Low temperature is found to be crucial for efficient solubilization of chitosan during the solvent exchange process. Increasing temperature to 50 °C leads to the formation of solid chitosan hydrogel. Chitosan in the water-based pseudosolution presents as positively charged particles. The pseudosolution shows a high positive zeta potential of about +52.6 mV and good colloidal stability. The water-based pseudosolutions with different amounts of chitosan contents exhibit the rheological features of weak liquid gels. By using these pseudosolutions, the fabrication of various chitosan materials is realized readily. Both chitosan pseudosolution and its downstream products are highly biocompatible. In this strategy, using IL as a solvent-medium and processing a low-temperature solvent exchange are the two key parameters to solubilize chitosan.

Chitosan nanoparticle toxicity: A comprehensive literature review of in vivo and in vitro assessments for medical applications

Topic definition

This literature review aims to update the current knowledge on toxicity of chitosan nanoparticles, compare the recent findings and identify the gaps with knowledge that is present for the chitosan nanoparticles.

Methods

The publications between 2010 and 2020 were searched in Science Direct, Pubmed.gov, Google Scholar, Research Gate, and ClinicalTrials.gov, according to the inclusion and exclusion criteria. 30 primary research studies were obtained from the literature review to compare the in vitro in vivo toxicity profiles among the chitosan nanoparticles.

Major highlights

Chitosan nanoparticles and other types of nanoparticles show cytotoxic effects on cancer cells while having minimal toxicity on normal cells. This apparent effect poses some considerations for use in incorporating cancer therapeutics into chitosan nanoparticles as an administration form. The concentration, duration of exposure, and pH of the solution can influence nanoparticle cytotoxicity, particularly in zebrafish. Different cell lines exhibit varying degrees of toxicity when exposed to nanoparticles, and of note are liver cells that show toxicity under exposure as indicated by increased alanine transaminase (ALT) levels. Aside from ALT, platelet aggregation can be considered a toxicity induced by chitosan nanoparticles. In addition, zebrafish cells experience the most toxicity, including organ damage, neurobehavioral impairment, and developmental abnormalities, when exposed to nanoparticles. However, nanoparticles may exhibit different toxicity profiles in different organisms, with brain toxicity and liver toxicity being present in zebrafish but not rats. Different organs exhibit varying degrees of toxicity, with the eye and mouth apparently having the lowest toxicity, while the brain, intestine, muscles and lung showing mixed results. Cardiotoxicity induced by chitosan nanoparticles was not observed in zebrafish embryos, and nanoparticles may reduce cardiotoxicity when delivering drug. Toxicity found in an organ may not necessarily mean that it is toxic towards all the cells found in that organ, as muscle toxicity was present when tested in zebrafish but not in C2C12 myoblast cells. Some of the studies conducted may have limitations that need to be reconsidered to account for differing results, with some examples being two experiments done on HeLa cells where one study concluded chitosan nanoparticles were toxic to the cells while the other seems to have no toxicity present. With regards to LD50, one study has stated the concentration of 64.21 mg/ml was found. Finally, smaller nanoparticles generally exhibit higher toxicity in cells compared to larger nanoparticles.

Scope for future work

This literature review did not uncover any published clinical trials with available results. Subsequent research endeavors should prioritize conducting clinical trials involving human volunteers to directly assess toxicity, rather than relying on cell or animal models.

Strategies for the Preparation of Chitosan Derivatives for Antimicrobial, Drug Delivery, and Agricultural Applications: A Review

Chitosan has received much attention for its role in designing and developing novel derivatives as well as its applications across a broad spectrum of biological and physiological activities, owing to its desirable characteristics such as being biodegradable, being a biopolymer, and its overall eco-friendliness. The main objective of this review is to explore the recent chemical modifications of chitosan that have been achieved through various synthetic methods. These chitosan derivatives are categorized based on their synthetic pathways or the presence of common functional groups, which include alkylated, acylated, Schiff base, quaternary ammonia, guanidine, and heterocyclic rings. We have also described the recent applications of chitosan and its derivatives, along with nanomaterials, their mechanisms, and prospective challenges, especially in areas such as antimicrobial activities, targeted drug delivery for various diseases, and plant agricultural domains. The accumulation of these recent findings has the potential to offer insight not only into innovative approaches for the preparation of chitosan derivatives but also into their diverse applications. These insights may spark novel ideas for drug development or drug carriers, particularly in the antimicrobial, medicinal, and plant agricultural fields.

Novel cross-linked polysaccharide-polyelectrolyte hemostatic foam improves survival compared to CombatGauze in swine femoral artery hemorrhage model

BACKGROUND

Uncontrolled hemorrhage is the leading cause of preventable death in combat and civilian trauma. Efficacious hemostatic agents in junctional hemorrhage can quell blood loss and improve survival. We hypothesized that a novel hemostatic foam of starch and chitosan would improve hemostasis, and thereby increase survival in a swine femoral artery hemorrhage model when compared with CombatGauze (CG).

METHODS

A novel hemostatic foam of starch and chitosan was created and modified during the study period. Thirty pigs (four excluded) were assigned to treatment using either foam version 1 (FV1, n = 9) or 2 (FV2, n = 8), or (n = 9) in a standard swine femoral artery hemorrhage model. Animals were observed for 150 minutes. Outcomes assessed included hemostasis, survival, posttreatment blood loss, IV fluid volume, and hemodynamic and laboratory trends.

RESULTS

Hemostasis prior to 150 minutes was similar with 44.4%, 77.8%, and 50% of swine treated with CG, FV1 and FV2, respectively (Kaplan-Meyer and log-rank test [KM-LR] p > 0.05). Survival to 150 minutes was improved in swine treated with FV1 (100%) compared with CG (55.6%) (KM-LR p = 0.02). Survival was similar between FV1 and FV2 (75%) (KM-LR p > 0.05), and between CG and FV2 (KM-LR p > 0.05). Using mixed model for longitudinal data, mean arterial pressure decreased significantly in CG- and FV2-treated swine, while there was no significant change in mean arterial pressure in FV1-treated swine. Trends in lactic acid, hematocrit, platelets, INR, and thrombelastography were more favorable for FV1 compared with CG.

CONCLUSION

In this preclinical study of junctional hemorrhage, survival was improved in swine treated with version 1 of a novel chitosan/starch foam compared with CG. Trends in hemodynamics and laboratory data were also more favorable in the FV1-treated swine. This novel hemostatic foam may be an effective alternative to current hemostatic agents.

Nano cellulose-laden alginate/chitosan sponge with enhanced biological and hemostatic behavior

Present study describes about hybrid hemostat developed with alginate (Alg), chitosan (Chito) and TEMPO-oxidized nanofibrillar cellulose (TOCNF) via lyophilization. All samples were analyzed under scanning electron microscopy (SEM) to determine their microstructure, size, and distribution of pores. Cell viability and proliferation of the scaffolds tested using fibroblast type L929 cells, showed it to be an excellent medium for cell generation. Blood coagulation started in ∼7.5 min, and most of the fibrin network formation took place in the Alg-Chito-TOCNF sponge, making it a suitable hemostatic material.

The Effect of Chitohem Bleeding Inhibitor Powder on Pain and Bleeding After Tonsillectomy by Suturing Method

Study Design and Objectives: This study aimed to investigate Triamcinolone ointment's effect on pain and bleeding after tonsillectomy by suturing method. Methods: The present study was performed as a single-blind clinical trial on 200 patients who underwent a total tonsillectomy in the ENT department of Loghman Hakim Hospital in Tehran during 2016. Candidates for total tonsillectomy were randomized into 2 groups one by one. Participants were randomly divided into 2 groups. Both groups matched homologically. Patients in both groups (intervention and control) underwent cold dissection total tonsillectomy. In addition to suturing, in the intervention group, Triamcinolone ointment was used to control the local bleeding at the surgical site. In the control group, only sutures were used to control bleeding. The studied variables included: bleeding and pain 24 hours after surgery, Time to start oral feeding. Result: The frequency of bleeding cases in the first 24 hours are included: 4 patients (5.63%) in the intervention group and 6 patients (8.45%) in the control group (P = 0.01). The average time to start eating for patients who were treated with topical triamcinolone ointment was significantly less than those who were not treated with this ointment. Only 2 patients (2.77%) in the intervention group took analgesics in the first 24 hours after surgery, while and 11 patients (15.3%) in the control group received analgesics in the same time period. Conclusion: In general, the results of this study showed that the use of Triamcinolone ointment in total tonsillectomy could reduce bleeding, analgesics usage, and the time of feeding onset.

Multiple Vaccines and Strategies for Pandemic Preparedness of Avian Influenza Virus

Avian influenza viruses (AIV) are a continuous cause of concern due to their pandemic potential and devasting effects on poultry, birds, and human health. The low pathogenic avian influenza virus has the potential to evolve into a highly pathogenic avian influenza virus, resulting in its rapid spread and significant outbreaks in poultry. Over the years, a wide array of traditional and novel strategies has been implemented to prevent the transmission of AIV in poultry. Mass vaccination is still an economical and effective approach to establish immune protection against clinical virus infection. At present, some AIV vaccines have been licensed for large-scale production and use in the poultry industry; however, other new types of AIV vaccines are currently under research and development. In this review, we assess the recent progress surrounding the various types of AIV vaccines, which are based on the classical and next-generation platforms. Additionally, the delivery systems for nucleic acid vaccines are discussed, since these vaccines have attracted significant attention following their significant role in the fight against COVID-19. We also provide a general introduction to the dendritic targeting strategy, which can be used to enhance the immune efficiency of AIV vaccines. This review may be beneficial for the avian influenza research community, providing ideas for the design and development of new AIV vaccines.

Recent Advances in Biodegradable and Biocompatible Synthetic Polymers Used in Skin Wound Healing

The treatment of skin wounds caused by trauma and pathophysiological disorders has been a growing healthcare challenge, posing a great economic burden worldwide. The use of appropriate wound dressings can help to facilitate the repair and healing rate of defective skin. Natural polymer biomaterials such as collagen and hyaluronic acid with excellent biocompatibility have been shown to promote wound healing and the restoration of skin. However, the low mechanical properties and fast degradation rate have limited their applications. Skin wound dressings based on biodegradable and biocompatible synthetic polymers can not only overcome the shortcomings of natural polymer biomaterials but also possess favorable properties for applications in the treatment of skin wounds. Herein, we listed several biodegradable and biocompatible synthetic polymers used as wound dressing materials, such as PVA, PCL, PLA, PLGA, PU, and PEO/PEG, focusing on their composition, fabrication techniques, and functions promoting wound healing. Additionally, the future development prospects of synthetic biodegradable polymer-based wound dressings are put forward. Our review aims to provide new insights for the further development of wound dressings using synthetic biodegradable polymers.

Comparison of hydroxocobalamin with other resuscitative fluids in volume-controlled and uncontrolled hemorrhage models in swine ( Sus-scrofa )

BACKGROUND

Traumatic hemorrhage is the leading cause of preventable death in military environments. Treatment with resuscitative fluids and blood components is based on availability, thus, frequently unavailable in the prehospital setting, due to lack of resources and costs. Hydroxocobalamin (HOC), increases blood pressure via nitric oxide scavenging. We evaluated HOC as a resuscitation fluid, in two swine hemorrhage models. Our objectives were to (1) evaluate whether HOC treatment following hemorrhagic shock improves hemodynamic parameters and (2) determine whether those effects are comparable to whole blood (WB) and lactated ringers (LR).

METHODS

Yorkshire swine (S us scrofa ) (n = 72) were used in models of controlled hemorrhage (CH) (n = 36) and uncontrolled hemorrhage (UH) (n = 36). Randomized animals received treatment with 500 mL of either WB, LR, HOC (150 mg/kg), followed by a six-hour observation (n = 6 each group). Survival, hemodynamics, blood gases (ABGs) and chemistries were collected. Data reported as mean ± standard error of the mean and statistical analysis by ANOVA ( p < 0.05).

RESULTS

Blood loss for CH was 41% ± 0.02 versus 33% ± 0.07 for UH. For CH, HOC treatment maintained higher systolic blood pressure (sBP, mm Hg) compared with WB and LR (72 ± 1.1; 60 ± 0.8; 58 ± 1.6; respectively). Heart rate (HR), cardiac output (CO), Sp o2 and vascular resistance were comparable with WB and LR. The ABG values were comparable between HOC and WB. For UH, HOC treatment maintained sBP levels comparable to WB and higher than LR (70 ± 0.9; 73 ± 0.5; 56 ± 1.2). HR, CO, Sp o2 , and systemic vascular resistance were comparable between HOC and WB. Survival, hemodynamics, blood gases were comparable between HOC and WB. No survival differences were found between cohorts.

CONCLUSION

Hydroxocobalamin treatment improved hemodynamic parameters and Ca 2+ levels compared with LR and equivalent to WB, in both models. Hydroxocobalamin may be a viable alternative when WB is not available.

Towards Formulation of Highly Acidic Active Ingredients: Development of Clinically Effective Concentrated Trichloroacetic Acid Gel for Wart Management

Common warts are benign skin lesions caused by the human papillomavirus. Although they are usually not harmful, they can cause pain, depending on their location. While many modalities are available for treatment of warts, none is a gold standard, and many are not affordable and/or have suboptimal outcomes. Trichloroacetic acid (TCA) is a chemical tissue-destroying agent used as a highly concentrated solution for wart management. While available and efficient, it is difficult to handle as the solution spreads to tissue surrounding the wart causing pain and burning. Hence, we developed a new polymer-based gel of high TCA content (100% w/v). Gels were formed successfully as hydroxyethyl cellulose (HEC) and chitosan were used to impart viscosity and bioadhesion. Formulae of different concentrations were tested for their physical properties, and the optimal formulation was selected for clinical evaluation. A combination of 3% HEC and 2% chitosan provided optimal viscosity and limited water content and have acceptable stability. The efficacy and safety of the biweekly application of TCA gel were evaluated in 30 patients. The clinical study revealed gel's efficacy and tolerability; half of the patients showed a complete cure, and 90% showed improvement within 6 weeks. Only 10-12% of the patients reported side effects. In summary, transforming TCA solution into a gel enabled its application and handling in a practical manner by physicians and patients alike, while maintaining its efficacy as a tissue-destroying agent. Moreover, it is economic and easy to apply, rendering it a promising formulation for similar conditions requiring controlled tissue ablation.

In Vivo Wound-Healing Effect of Chemical and Green Synthesized Chitosan Nanoparticles Using Lawsonia inermis Ethanolic Extract

Wounds can be a result of surgery, an accident, or other factors. There is still a challenge to find effective topical wound-healing agents. This study aims to investigate the wound-healing activity of chemical and green synthesized chitosan nanoparticles (Ch-NPs) using Lawsonia inermis leaves extract. The nanoparticles were morphologically and chemically characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and high-resolution transmission electron microscopy (HRTEM). Forty-five adult female albino rats were randomly divided into three groups. The cutaneous surgical wounds were topically treated with 0.9% normal saline (control group), green Ch-NPs (second group), and chemical Ch-NPs gels (third group), respectively. The clinical picture of wounds and histopathological changes were assessed on the 3rd, 7th, 14th, and 21st days post-treatment. X-ray diffraction analysis revealed great crystallinity and purity of nanoparticles. The studied nanoparticles increased the wound contraction percent (WC%), reduced healing time and wound surface area (WSA), and these results were backed up by histological findings that indicated improved epithelialization, dermal differentiation, collagen deposition, and angiogenesis in treated rats compared with control rats (p < 0.05). We concluded that the wound-healing effects of the studied nanoparticles are encouraging, and further studies for complete assessment are still needed.

Tunicate-mimetic antibacterial hydrogel based on metal ion crosslinking and chitosan functionalization for wound healing

With the increasing prevalence of drug-resistant bacterial infections and frequent occurrences of slow wound healing, the development of novel antibacterial wound dressings has become a serious challenge. Hydrogel dressings have attracted extensive attention on wound healing due to their unique three-dimensional network structures and properties. However, it is a challenge to develop natural long-acting antibacterial hydrogels with multiple functions such as excellent cell affinity, wet adhesion and mechanical properties. Inspired by the wound healing mechanism and adhesion characteristics of tunicates, a series of biomimetic antibacterial hydrogels were prepared by utilizing pyrogallol-modified chitosan (GACS) and polyvinyl alcohol (PVA) as matrix, zinc ions (Zn²⁺) as crosslinking and antibacterial agents, and ethyl N-lauroyl l-arginate hydrochloride (LAE) as the antibacterial active ingredient. The morphology, swelling, water retention, degradability, wet adhesion, biocompatibility, mechanical and rheological properties of PVA/GACS/Zn²⁺/LAE hydrogels were evaluated. And the adhesion ability conferred by the pyrogallol structures enabled the hydrogel with enhanced antibacterial effect and hemostatic ability. Moreover, the in vivo experiments on rat models with full-thickness infected wounds confirmed that PVA/GACS/Zn²⁺/LAE hydrogels could efficiently kill bacteria, significantly improve the wound microenvironment, greatly promote fibroblast proliferation and collagen deposition and ultimately accelerate wound healing. In a word, this study provided a feasible and simple way for the development of biomimetic antibacterial hydrogel dressings applied in infected wounds, which could not only seal wounds with various shapes and provide a moist and antibacterial environment for wounds, but also have certain mechanical strength, excellent wound adhesion, good biocompatibility and hemostatic performance.

Zeolites as Ingredients of Medicinal Products

Development of new medicinal products for particular therapeutic treatment or for better manipulations with better quality and less side effects are possible as a result of advanced inorganic and organic materials application, among which zeolites, due to their properties and versatility, have been gaining attention. This paper is an overview of the development in the use of zeolite materials and their composites and modifications as medicinal products for several purposes such as active agents, carriers, for topical treatments, oral formulations, anticancer, the composition of theragnostic systems, vaccines, parenteral dosage forms, tissue engineering, etc. The objective of this review is to explore the main properties of zeolites and associate them with their drug interaction, mainly addressing the advances and studies related to the use of zeolites for different types of treatments due to their zeolite characteristics such as molecule storage capacity, physical and chemical stability, cation exchange capacity, and possibility of functionalization. The use of computational tools to predict the drug-zeolite interaction is also explored. As conclusion was possible to realize the possibilities and versatility of zeolite applications as being able to act in several aspects of medicinal products.

Pentoxifylline/Chitosan Films on Wound Healing: In Vitro/In Vivo Evaluation

This study aimed to develop films of chitosan (CSF) associated with pentoxifylline (PTX) for healing cutaneous wounds. These films were prepared at two concentrations, F1 (2.0 mg/mL) and F2 (4.0 mg/mL), and the interactions between the materials, structural characteristics, in vitro release, and morphometric aspects of skin wounds in vivo were evaluated. The formation of the CSF film with acetic acid modifies the polymeric structure, and the PTX demonstrates interaction with the CSF, in a semi-crystalline structure, for all concentrations. The release for all films was proportional to the concentration, with two phases: a fast one of ≤2 h and a slow one of >2 h, releasing 82.72 and 88.46% of the drug after 72 h, being governed by the Fickian diffusion mechanism. The wounds of the mice demonstrate a reduction of up to 60% in the area on day 2 for F2 when compared to CSF, F1, and positive control, and this characteristic of faster healing speed for F2 continues until the ninth day with wound reduction of 85%, 82%, and 90% for CSF, F1, and F2, respectively. Therefore, the combination of CSF and PTX is effective in their formation and incorporation, demonstrating that a higher concentration of PTX accelerates skin-wound reduction.

Anti-COVID-19 Credentials of Chitosan Composites and Derivatives: Future Scope?

Chitosan derivatives and composites are the next generation polymers for biomedical applications. With their humble origins from the second most abundant naturally available polymer chitin, chitosan is currently one of the most promising polymer systems, with wide biological applications. This current review gives a bird’s eye view of the antimicrobial applications of chitosan composites and derivatives. The antiviral activity and the mechanisms behind the inhibitory activity of these components have been reviewed. Specifically, the anti-COVID-19 aspects of chitosan composites and their derivatives have been compiled from the existing scattered reports and presented. Defeating COVID-19 is the battle of this century, and the chitosan derivative-based combat strategies naturally become very attractive. The challenges ahead and future recommendations have been addressed.

Application of depolymerized chitosan in crop production: A review

Currently, chitosan (CHT) is well known for its uses, particularly in veterinary and agricultural fields. However, chitosan's uses suffer greatly due to its extremely solid crystalline structure, it is insoluble at pH levels above or equal to 7. This has sped up the process of derivatizing and depolymerizing it into low molecular weight chitosan (LMWCHT). As a result of its diverse physicochemical as well as biological features which include antibacterial activity, non-toxicity, and biodegradability, LMWCHT has evolved into new biomaterials with extremely complex functions. The most important physicochemical and biological property is antibacterial, which has some degree of industrialization today. CHT and LMWCHT have potential due to the antibacterial and plant resistance-inducing properties when applied in crop production. This study has highlighted the many advantages of chitosan derivatives as well as the most recent studies on low molecular weight chitosan applications in crop development.

Sprayable surface-adaptive biocompatible membranes for efficient hemostasis via assembly of chitosan and polyphosphate

This work describes a hemostatic membrane system (or surface coating) based on spray-assisted layer-by-layer electrostatic assemblies of oppositely charged polyphosphate (polyP) and chitosan (Cs). The as-prepared membrane formed a robust micro-stratified porous structure with high flexibility. Both blood clotting test and rodent hepatic severe hemorrhage model revealed the excellent hemostatic performance of the membrane system, benefitting from the robust assembly and synergistic effect of polyP/Cs as well as membrane surface chemistry. Compared to Cs-topped membrane surface, polyP-sprayed one exhibited further improved hemostatic effect via promoting fibrin formation. Besides, comprehensive in vitro and in vivo evaluations demonstrated good biocompatibility and biodegradability of the membrane. The present approach that integrated the hemostasis-stimulating capability of polyP/Cs with facile spraying method is highly scalable and flexible, which is envisioned to be adapted readily for other hemostatic polyelectrolytes and surface functionalization of diverse existing hemostatic products on demand.

Carboxymethyl Chitosan/Tannic Acid Hydrogel with Antibacterial, Hemostasis, and Antioxidant Properties Promoting Skin Wound Repair

Local causes of slow wound healing include infection and wound hemorrhage. Using sodium bicarbonate as a neutralizer, a variety of carboxymethyl chitosan-tannic acid (CMC-TA) composite hydrogels solidify through hydrogen bonding in this study. The best-performing hydrogel was synthesized by altering the concentration of TA and exhibited remarkable mechanical properties and biocompatibility. Following in vitro characterization tests, the CMC-TA hydrogel exhibited remarkable antibacterial and antioxidant properties, as well as quick hemostasis capabilities. In the in vivo wound healing study, the results showed that the CMC-TA hydrogel could relieve inflammation and promote the recovery of skin incision, re-epithelialization, and collagen deposition. Overall, this multifunctional hydrogel could be an ideal wound dressing for the clinical therapy of full-thickness wounds.

Zinc improves antibacterial, anti-inflammatory and cell motility activity of chitosan for wound healing applications

We report the successful preparation and characterization of chitosan-Zn complex (ChiZn) in the form of films, intended to enhance the biological performance of chitosan by the presence of Zn as antibacterial agent and biologically active ion. The influence of Zn chelation on morphology and structure of chitosan was assessed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and infrared spectroscopy. The biodegradability study of ChiZn showed a sustained release of Zn up to 2 mg/mL. No toxic response was observed toward stromal cell line ST-2 in indirect contact with the ChiZn films. The dissolution product of ChiZn showed improved wound closure (88% closure) compared to the positive control group (70% closure). Moreover, ChiZn exhibited antibacterial activity against S. aureus together with a slight increase (~30%) in the secretion of VEGF and moderate decrease in nitric oxide evolution. Our findings indicate that ChiZn could be used as a safe and effective wound healing agent.

Medical Adhesives and Their Role in Laparoscopic Surgery—A Review of Literature

Laparoscopic surgery is undergoing rapid development. Replacing the traditional method of joining cut tissues with sutures or staples could greatly simplify and speed up laparoscopic procedures. This alternative could undoubtedly be adhesives. For decades, scientists have been working on a material to bond tissues together to create the best possible conditions for tissue regeneration. The results of research on tissue adhesives achieved over the past years show comparable treatment effects to traditional methods. Tissue adhesives are a good alternative to surgical sutures in wound closure. This article is a review of the most important groups of tissue adhesives including their properties and possible applications. Recent reports on the development of biological adhesives are also discussed.

Chitosan-modified nanocarriers as carriers for anticancer drug delivery: Promises and hurdles

With the advent of drug delivery, various polymeric materials are being explored to fabricate numerous nanocarriers. Each polymer is associated with a few characteristics attributes which further facilitate its usage in drug delivery. One such polymer is chitosan (CS), which is extensively employed to deliver a variety of drugs to various targets, especially to cancer cells. The desired properties like biological origin, bio-adhesive, biocompatibility, the scope of chemical modification, biodegradability and controlled drug release make it a highly rough after polymer in pharmaceutical nanotechnology. The present review attempts to compile various chemical modifications on CS and showcase the outcomes of the derived nanocarriers, especially in cancer chemotherapy and drug delivery.

Applications of Chitosan in Surgical and Post-Surgical Materials

The continuous advances in surgical procedures require continuous research regarding materials with surgical applications. Biopolymers are widely studied since they usually provide a biocompatible, biodegradable, and non-toxic material. Among them, chitosan is a promising material for the development of formulations and devices with surgical applications due to its intrinsic bacteriostatic, fungistatic, hemostatic, and analgesic properties. A wide range of products has been manufactured with this polymer, including scaffolds, sponges, hydrogels, meshes, membranes, sutures, fibers, and nanoparticles. The growing interest of researchers in the use of chitosan-based materials for tissue regeneration is obvious due to extensive research in the application of chitosan for the regeneration of bone, nervous tissue, cartilage, and soft tissues. Chitosan can serve as a substance for the administration of cell-growth promoters, as well as a support for cellular growth. Another interesting application of chitosan is hemostasis control, with remarkable results in studies comparing the use of chitosan-based dressings with traditional cotton gauzes. In addition, chitosan-based or chitosan-coated surgical materials provide the formulation with antimicrobial activity that has been highly appreciated not only in dressings but also for surgical sutures or meshes.

The Design and Feasibility of the: Radial Artery Puncture Hemostasis Evaluation – RAPHE Study, a Prospective, Randomized, Multicenter Clinical Trial

Introduction and Aim

Radial artery approach angiography is the current gold standard for coronary status diagnostics and eventual percutaneous revascularization (PCI). Currently, application of adequate, patent hemostasis based physical torniquets are used for puncture site control, to avoid bleeding, radial artery occlusion and damage (RAO and RAD). The Radial Artery Puncture Hemostasis Evaluation (RAPHE) is a prospective, randomized, multicenter clinical trial designed to investigate new, simplified techniques of radial artery hemostasis utilizing physical compression free methods.

Methods and Results

The RAPHE study has been designed to evaluate the efficacy and safety of two non-compression based radial artery hemostasis methods: a 100% chitosan bioactive hemostatic dressing and a purpose-built radial potassium-ferrate based topical hemostasis disc. These devices will be investigated in a standalone configuration. Control group is a standard pneumatic airbladder-based compression device. A total of 600 patients will be enrolled in a three-way randomization (1:1:1) with two study and one control groups. Safety and efficacy endpoints are RAO, puncture site hematoma formation and RAD respectively, consisting of dissection, (pseudo)aneurism and/or fistula formation, measured post-procedure and at sixty days.

Conclusion

The results from this trial will provide valuable information on new, simplified methods of radial artery hemostasis options and possibly simplify post-puncture management of patients.

Clinical Trial Registration

[www.ClinicalTrials.gov], identifier [NCT04857385].

Nano vaccines for T. gondii Ribosomal P2 Protein With Nanomaterials as a Promising DNA Vaccine Against Toxoplasmosis

Caused by Toxoplasma gondii, toxoplasmosis has aroused great threats to public health around the world. So far, no effective vaccine or drug is commercially available, and the demands for a safe and effective therapeutic strategy have become more and more urgent. In the current study, we constructed a DNA vaccine encoding T. gondii ribosomal P2 protein (TgP2) and denoted as TgP2-pVAX1 plasmid. To improve the immunoprotection, nanomaterial poly-lactic-co-glycolic acid (PLGA) and chitosan were used as the delivery vehicle to construct TgP2-pVAX1/PLGA and TgP2-pVAX1/CS nanospheres. Before vaccinations in BALB/c mice, TgP2-pVAX1 plasmids were transiently transfected into Human Embryonic Kidney (HEK) 293-T cells, and the expression of the eukaryotic plasmids was detected by laser confocal microscopy and Western blotting. Then the immunoprotection of naked DNA plasmids and their two nano-encapsulations were evaluated in the laboratory animal model. According to the investigations of antibody, cytokine, dendritic cell (DC) maturation, molecule expression, splenocyte proliferation, and T lymphocyte proportion, TgP2-pVAX1 plasmid delivered by two types of nanospheres could elicit a mixed Th1/Th2 immune response and Th1 immunity as the dominant. In addition, TgP2-pVAX1/PLGA and TgP2-pVAX1/CS nanospheres have great advantages in enhancing immunity against a lethal dose of T. gondii RH strain challenge. All these results suggested that TgP2-pVAX1 plasmids delivered by PLGA or chitosan nanomaterial could be promising vaccines in resisting toxoplasmosis and deserve further investigations and applications.

Silk Fibroin-Based Biomaterials for Hemostatic Applications

Hemostasis plays an essential role in all surgical procedures. Uncontrolled hemorrhage is the primary cause of death during surgeries, and effective blood loss control can significantly reduce mortality. For modern surgeons to select the right agent at the right time, they must understand the mechanisms of action, the effectiveness, and the possible adverse effects of each agent. Over the past decade, various hemostatic agents have grown intensely. These agents vary from absorbable topical hemostats, including collagen, gelatins, microfibrillar, and regenerated oxidized cellulose, to biologically active topical hemostats such as thrombin, biological adhesives, and other combined agents. Commercially available products have since expanded to include topical hemostats, surgical sealants, and adhesives. Silk is a natural protein consisting of fibroin and sericin. Silk fibroin (SF), derived from silkworm Bombyx mori, is a fibrous protein that has been used mostly in fashion textiles and surgical sutures. Additionally, SF has been widely applied as a potential biomaterial in several biomedical and biotechnological fields. Furthermore, SF has been employed as a hemostatic agent in several studies. In this review, we summarize the several morphologic forms of SF and the latest technological advances on the use of SF-based hemostatic agents.

Transplantation of neuron‐inducing grafts embedding positively charged gold nanoparticles for the treatment of spinal cord injury

In this study, we aimed to investigate the recovery after traumatic spinal cord injury (SCI) by inducing cellular differentiation of transplanted neural stem cells (NSCs) into neurons. We dissociated NSCs from the spinal cords of Fisher 344 rat embryos. An injectable gel crosslinked with glycol chitosan and oxidized hyaluronate was used as a vehicle for NSC transplantation. The gel graft containing the NSC and positively charged gold nanoparticles (pGNP) was implanted into spinal cord lesions in Sprague–Dawley rats (NSC‐pGNP gel group). Cellular differentiation of grafted NSCs into neurons (stained with β‐tubulin III [also called Tuj1]) was significantly increased in the NSC‐pGNP gel group (***p < 0.001) compared to those of two control groups (NSC and NSC gel groups) in the SCI conditions. The NSC‐pGNP gel group showed the lowest differentiation into astrocytes (stained with glial fibrillary acidic protein). Regeneration of damaged axons (stained with biotinylated dextran amines) within the lesion was two‐fold higher in the NSC‐pGNP gel group than that in the NSC gel group. The highest locomotor scores were also found in the NSC‐pGNP gel group. These outcomes suggest that neuron‐inducing pGNP gel graft embedding embryonic spinal cord‐derived NSCs can be a useful type of stem cell therapy after SCI.

Preparation and characterization of bifunctional edible gellan-polylysine fiber

A gellan-polylysine (GPL) fiber was prepared by wet spinning molding with gellan solution containing glucose, soybean peptide, fish collagen peptide as spinning liquid, and ε-poly-l-lysine as fixative liquid. Results showed that the material addition order affects the spinning and an acceptable material addition order was as follows: soybean peptides →glucose → fish collagen peptides. The mechanical strength of the GPL fiber decreased with the collagen peptide titer and the fiber strength can reach 0.99 cN/dtex. In addition, the GPL fiber showed comparable water absorption capacity. The GPL fiber demonstrated good antibacterial properties against Escherichia coli and Staphylococcus aureus. The GPL fiber also had no cytotoxicity on mouse embryo fibroblast L-929 cells and could effectively promote wound healing for rats. As a result, the bifunctional edible GPL fiber is potentially used as a military and rescue emergency equipment.

Exploring the Impact of Chitosan Composites as Artificial Organs

Chitosan and its allies have in multiple ways expanded into the medical, food, chemical, and biological industries and is still expanding. With its humble beginnings from marine shell wastes, the deacetylated form of chitin has come a long way in clinical practices. The biomedical applications of chitosan are truly a feather on its cap, with rarer aspects being chitosan’s role in tissue regeneration and artificial organs. Tissue regeneration is a highly advanced and sensitive biomedical application, and the very fact that chitosan is premiering here is an authentication of its ability to deliver. In this review, the various biomedical applications of chitosan are touched on briefly. The synthesis methodologies that are specific for tissue engineering and biomedical applications have been listed. What has been achieved using chitosan and chitosan composites in artificial organ research as well as tissue regeneration has been surveyed and presented. The lack of enthusiasm, as demonstrated by the very few reports online with respect to chitosan composites and artificial organs, is highlighted, and the reasons for this lapse speculated. What more needs be done to expand chitosan and its allies for a better utilization and exploitation to best benefit the construction of artificial organs and building of tissue analogs has been discussed.

Analysis of clinical trials on biomaterial and therapeutic applications of chitosan: A review

Chitosan is a modified natural carbohydrate polymer derived from chitin that occurs in many natural sources. It has a diverse range of applications in medical and pharmaceutical sciences. Its primary and permitted use is biomaterial in medical devices. Chitosan and its derivatives also find utility in pharmaceuticals as an excipient, drug carrier, or therapeutic agent. The USFDA has approved chitosan usage as a biomaterial but not for pharmaceutical use, primarily because of the concerns over its source, purity, and immunogenicity. A large number of clinical studies are underway on chitosan-based materials/ products because of their diverse applications. Herein, we analyze clinical studies to understand their clinical usage portfolio. Our analysis shows that >100 clinical studies are underway to investigate the safety/efficacy of chitosan or its biomaterials/ nanoparticles, comprising ~95% interventional and ~ 5% observational studies. The regulatory considerations that limit the use of chitosan in pharmaceuticals are also deliberated. TEASER: Clinical Trials of Chitosan.

Nature-Derived and Synthetic Additives to poly(ɛ-Caprolactone) Nanofibrous Systems for Biomedicine; an Updated Overview

As a low cost, biocompatible, and bioresorbable synthetic polymer, poly (ɛ-caprolactone) (PCL) is widely used for different biomedical applications including drug delivery, wound dressing, and tissue engineering. An extensive range of in vitro and in vivo tests has proven the favourable applicability of PCL in biomedicine, bringing about the FDA approval for a plethora of PCL made medical or drug delivery systems. This popular polymer, widely researched since the 1970s, can be readily processed through various techniques such as 3D printing and electrospinning to create biomimetic and customized medical products. However, low mechanical strength, insufficient number of cellular recognition sites, poor bioactivity, and hydrophobicity are main shortcomings of PCL limiting its broader use for biomedical applications. To maintain and benefit from the high potential of PCL, yet addressing its physicochemical and biological challenges, blending with nature-derived (bio)polymers and incorporation of nanofillers have been extensively investigated. Here, we discuss novel additives that have been meant for enhancement of PCL nanofiber properties and thus for further extension of the PCL nanofiber application domain. The most recent researches (since 2017) have been covered and an updated overview about hybrid PCL nanofibers is presented with focus on those including nature-derived additives, e.g., polysaccharides and proteins, and synthetic additives, e.g., inorganic and carbon nanomaterials.

Emerging Biopolymer-Based Bioadhesives

Bioadhesives have been widely used in healthcare and biomedical applications due to their ease-of-operation for wound closure and repair compared to conventional suturing and stapling. However, several challenges remain for developing ideal bioadhesives, such as unsatisfied mechanical properties, non-tunable biodegradability, and limited biological functions. Considering these concerns, naturally derived biopolymers have been considered good candidates for making bioadhesives owing to their ready availability, facile modification, tunable mechanical properties, and desired biocompatibility and biodegradability. Over the past several years, remarkable progress has been made on biopolymer-based adhesives, covering topics from novel materials designs and advanced processing to clinical translation. The developed bioadhesives have been applied for diverse applications, including tissue adhesion, hemostasis, antimicrobial, wound repair/tissue regeneration, and skin-interfaced bioelectronics. Here in this comprehensive review, recent progress on biopolymer-based bioadhesives is summarized with focuses on clinical translations and multifunctional bioadhesives. Furthermore, challenges and opportunities such as weak adhesion strength at the hydrated state, mechanical mismatch with tissues, and unfavorable immune responses are discussed with an aim to facilitate the future development of high-performance biopolymer-based bioadhesives.

In-vitro and in-vivo hemostat evaluation of decellularized liver extra cellular matrix loaded chitosan/gelatin spongy scaffolds for liver injury

Individually, Chitosan (C) and Gelatin (G) are increasingly being used for the simulation and testing of surgical procedures. In the present study, at combination of chitosan/gelatin (CG) was optimized and later enriched by the loading decellularized liver extracellular matrix powder (dLECM) prepared from porcine liver, we hypothesized CG-dLECM combination would enhance wound healing and reduce postoperative complications after liver surgery. Varying concentration of dLECM (1, 4, and 8 mg/ml) were loaded into CG, and evaluation was done to get the optimized composition. Preliminary analysis on the microstructure, in-vitro degradation, and blood clot kinetics and in-vitro cytocompatibility showed that the CG with 4 mg/ml dLECM (CG-E4) was the most suitable composition for further consideration. The prepared CG-E4 spongy scaffold enhances fast post-operative recovery with a higher blood absorption and fast clotting time (~50 s). In addition, CG-E4 spongy scaffold implanted at rat liver wound showed desired biocompatibility as evidenced by reduced wound size, earlier bioabsorption and accelerated liver regeneration. In the present study, we demonstrated that, CG with dLECM spongy scaffold as a potential hemostatic material in the prevention of excessive hemorrhage during surgeries.

Recent Advancement in Chitosan-Based Nanoparticles for Improved Oral Bioavailability and Bioactivity of Phytochemicals: Challenges and Perspectives

The excellent therapeutic potential of a variety of phytochemicals in different diseases has been proven by extensive studies throughout history. However, most phytochemicals are characterized by a high molecular weight, poor aqueous solubility, limited gastrointestinal permeability, extensive pre-systemic metabolism, and poor stability in the harsh gastrointestinal milieu. Therefore, loading of these phytochemicals in biodegradable and biocompatible nanoparticles (NPs) might be an effective approach to improve their bioactivity. Different nanocarrier systems have been developed in recent decades to deliver phytochemicals. Among them, NPs based on chitosan (CS) (CS-NPs), a mucoadhesive, non-toxic, and biodegradable polysaccharide, are considered the best nanoplatform for the oral delivery of phytochemicals. This review highlights the oral delivery of natural products, i.e., phytochemicals, encapsulated in NPs prepared from a natural polymer, i.e., CS, for improved bioavailability and bioactivity. The unique properties of CS for oral delivery such as its mucoadhesiveness, non-toxicity, excellent stability in the harsh environment of the GIT, good solubility in slightly acidic and alkaline conditions, and ability to enhance intestinal permeability are discussed first, and then the outcomes of various phytochemical-loaded CS-NPs after oral administration are discussed in detail. Furthermore, different challenges associated with the oral delivery of phytochemicals with CS-NPs and future directions are also discussed.

Harnessing Multifaceted Next-Generation Technologies for Improved Skin Wound Healing

Dysregulation of sequential and synchronized events of skin regeneration often results in the impairment of chronic wounds. Conventional wound dressings fail to trigger the normal healing mechanism owing to the pathophysiological conditions. Tissue engineering approaches that deal with the fabrication of dressings using various biomaterials, growth factors, and stem cells have shown accelerated healing outcomes. However, most of these technologies are associated with difficulties in scalability and cost-effectiveness of the products. In this review, we survey the latest developments in wound healing strategies that have recently emerged through the multidisciplinary approaches of bioengineering, nanotechnology, 3D bioprinting, and similar cutting-edge technologies to overcome the limitations of conventional therapies. We also focus on the potential of wearable technology that supports complete monitoring of the changes occurring in the wound microenvironment. In addition, we review the role of advanced devices that can precisely enable the delivery of nanotherapeutics, oligonucleotides, and external stimuli in a controlled manner. These technological advancements offer the opportunity to actively influence the regeneration process to benefit the treatment regime further. Finally, the clinical relevance, trajectory, and prospects of this field have been discussed in brief that highlights their potential in providing a beneficial wound care solution at an affordable cost.

Poly(N-vinyl imidazole) Cross-Linked β-Cyclodextrin Hydrogel for Rapid Hemostasis in Severe Renal Arterial Hemorrhagic Model

A unique facile process has been adopted for fast assembly of a poly(N-vinyl imidazole) cross-linked β-cyclodextrin hydrogel through microwave-assisted free radical polymerization, using N,N'-methylenebis(acrylamide) cross-linker. The copolymer possesses positive surface charge, one of the characteristic properties of an ideal hemostatic hydrogel. The functionalized imidazole-based hydrogel demonstrates rapid, superior blood coagulation kinetics under in vitro and in vivo conditions. On application to a major renal arterial hemorrhagic model, this hydrogel shows better blood clotting kinetics, leading to complete hemostasis in as few as ∼144 ± 7 s. Additionally, 350 μL of whole blood was clotted instantly, in ∼35 s, and therefore, reinforcing its hemostatic potential. The hydrogel demonstrates excellent biocompatibility, when seeded with human dermal fibroblast cells, retaining the native property of its predecessor. In addition, the hydrogel presents excellent hemocompatibility when tested with whole blood with the highest hemolytic ratio of 1.07 ± 0.05%. Moreover, it also demonstrates potential as a carrier for sustained release of an anesthetic drug, lidocaine hydrochloride monohydrate (∼83% in 24 h). The rapid hemostatic behavior of the hydrogel is coupled with its cytocompatibility and hemocompatibilty properties along with controlled drug release characteristics. These behaviors evidently demonstrate it to be an excellent alternative for a superior hemostatic material for severe hemorrhagic conditions.

Multi-Scale Photoacoustic Assessment of Wound Healing Using Chitosan-Graphene Oxide Hemostatic Sponge

Hemostasis is vital to save lives, reducing risks of organ failure and hemorrhagic shock. Exploring novel hemostatic materials and precise monitoring of the hemostatic status is of great importance for efficient hemostasis. We present the development of chitosan-graphene oxide-based hemostatic composite and multi-scale photoacoustic evaluation of the hemostatic performance. The hemostatic sponge can quickly and efficiently absorb the blood with its porous cavity and specific surficial property. We inspect the hemostatic performance via an in vitro blood absorption test and in vivo mouse bleeding injury experiments. Results show that the synthesized hemostatic sponge can not only absorb plasma in blood fast with its interior porous structure but also stimulate the interfacial reaction with erythrocytes and platelets. The superiority of multi-scale photoacoustic imaging for guiding, monitoring, and evaluating the hemostatic stages of sponges is demonstrated with high spatial resolution and great sensitivity at depths. Photoacoustic evaluation of a chitosan-graphene oxide-based hemostatic sponge has the potential to be transferred toward the clinical assessment of wound healing.

Nano DNA Vaccine Encoding Toxoplasma gondii Histone Deacetylase SIR2 Enhanced Protective Immunity in Mice

The pathogen of toxoplasmosis, Toxoplasma gondii (T. gondii), is a zoonotic protozoon that can affect the health of warm-blooded animals including humans. Up to now, an effective vaccine with completely protection is still inaccessible. In this study, the DNA vaccine encoding T. gondii histone deacetylase SIR2 (pVAX1-SIR2) was constructed. To enhance the efficacy, chitosan and poly (d, l-lactic-co-glycolic)-acid (PLGA) were employed to design nanospheres loaded with the DNA vaccine, denoted as pVAX1-SIR2/CS and pVAX1-SIR2/PLGA nanospheres. The pVAX1-SIR2 plasmids were transfected into HEK 293-T cells, and the expression was evaluated by a laser scanning confocal microscopy. Then, the immune protections of pVAX1-SIR2 plasmid, pVAX1-SIR2/CS nanospheres, and pVAX1-SIR2/PLGA nanospheres were evaluated in a laboratory animal model. The in vivo findings indicated that pVAX1-SIR2/CS and pVAX1-SIR2/PLGA nanospheres could generate a mixed Th1/Th2 immune response, as indicated by the regulated production of antibodies and cytokines, the enhanced maturation and major histocompatibility complex (MHC) expression of dendritic cells (DCs), the induced splenocyte proliferation, and the increased percentages of CD4⁺ and CD8⁺ T lymphocytes. Furthermore, this enhanced immunity could obviously reduce the parasite burden in immunized animals through a lethal dose of T. gondii RH strain challenge. All these results propose that pVAX1-SIR2 plasmids entrapped in chitosan or PLGA nanospheres could be the promising vaccines against acute T. gondii infections and deserve further investigations.

Hemostatic dressings based on poly(vinyl formal) sponges

The development of novel hemostatic agents is related to the fact that severe blood loss due to hemorrhage continues to be the leading cause of preventable death of patients with military trauma and the second leading cause of death of civilian patients with injuries. Herein we assessed the hemostatic properties of porous sponges based on biocompatible hydrophilic polymer, poly(vinyl formal) (PVF), which meets the main requirements for the development of hemostatic materials. A series of composite hemostatic materials based on PVF sponges with different porosities and fillers were synthesized by acetalization of poly(vinyl alcohol) with formaldehyde. Nano-sized aminopropyl silica, micro-sized calcium carbonate, and chitosan hydrogel were used to modify PVF matrixes. The physicochemical properties (pore size, elemental composition, functional groups, hydrophilicity, and acetalization degree) of the synthesized composite sponges were studied by gravimetrical analysis, optical microscopy, scanning electron microscopy combined with energy dispersive x-ray spectroscopy, infrared spectroscopy, and nuclear magnetic resonance. Hemostatic properties of the materials were assessed using a model of parenchymal bleeding from the liver of white male Wistar rat with a gauze bandage as a control. All investigated PVF-based porous sponges showed high hemostatic activity: upon the application of PVF-samples the bleeding decreased within 3 min by 68.4-94.4% (р < 0.001). The bleeding time upon the application of PVF-based composites decreased by 78.3-90.4% (p < 0.001) compared to the application of well-known commercial product Celox™.