Cytotoxicity, bactericidal and hemostatic evaluation of oxidized cellulose microparticles: Structure and oxidation degree approach

Platelet Vesicles Synergetic with Biosynthetic Cellulose Aerogels for Ultra-Fast Hemostasis and Wound Healing

Achieving hemostasis in penetrating and irregular wounds is challenging because the hemostasis factor cannot arrive at the bleeding site, and substantial bleeding will wash away the blood clot. Since the inherently gradual nature of blood clot formation takes time, a physical barrier is needed before blood clot formation. Herein, an ultra-light and shape memory hemostatic aerogel consisting of oxidized bacterial cellulose (OBC) and platelet extracellular vesicles (pVEs) is reported. The OBC-pVEs aerogel provides a physical barrier for the bleeding site by self-expansion, absorbing the liquid from blood to concentrate platelets and clotting factors and accelerating the clot formation by activating platelets and transforming fibrinogen into fibrin. In the rat liver and tail injury models, the blood loss decreases by 73% and 59%, and the bleeding times are reduced by 55% and 62%, respectively. OBC-pVEs aerogel has also been shown to accelerate wound healing. In conclusion, this work introduces an effective tool for treating deep, non-compressible, and irregular wounds and offers valuable strategies for trauma bleeding and wound treatment.

Advances of biological macromolecules hemostatic materials: A review

Achieving hemostasis is a necessary intervention to rapidly and effectively control bleeding. Conventional hemostatic materials currently used in clinical practice may aggravate the damage at the bleeding site due to factors such as poor adhesion and poor adaptation. Compared to most traditional hemostatic materials, polymer-based hemostatic materials have better biocompatibility and offer several advantages. They provide a more effective method of stopping bleeding and avoiding additional damage to the body in case of excessive blood loss. Various hemostatic materials with greater functionality have been developed in recent years for different organs using diverse design strategies. This article reviews the latest advances in the development of polymeric hemostatic materials. We introduce the coagulation cascade reaction after bleeding and then discuss the hemostatic mechanisms and advantages and disadvantages of various polymer materials, including natural, synthetic, and composite polymer hemostatic materials. We further focus on the design strategies, properties, and characterization of hemostatic materials, along with their applications in different organs. Finally, challenges and prospects for the application of hemostatic polymeric materials are summarized and discussed. We believe that this review can provide a reference for related research on hemostatic materials, contributing to the further development of polymer hemostatic materials.

Silver-infused lysine crosslinked hydrogel with oxidized regenerated cellulose for prospective advanced wound dressings

The study aimed to develop a multifunctional wound dressing with enhanced antibacterial properties and wound healing promotion. The synthesis process involved preparing oxidized regenerated cellulose (ORC) following a modified procedure, synthesizing chitosan/silver nanoparticles (CS/Ag NPs) via an in-situ reduction method, and subsequently preparing ORC/CS/Lys@Ag NPs hydrogels. Characterization techniques including FTIR, XRD, SEM, and EDS were employed to analyze functional groups, lattice structure, morphology, and elemental composition. Gelation time, swelling behavior, water retention, mechanical properties, viscosity, self-healing capacity, rheological behavior, oxygen permeability, in vitro degradation, release of Ag+, and antibacterial properties were evaluated using various experimental methods. Results indicated that the novel wound dressing has the capability to evenly distribute Ag NPs to effectively counteract bacteria. It can maintain moist conditions for 86 h, resist a sturdy mechanical pressure of 11.3 KPa, and degrade by 11.045 % ± 0.429 within 8 h. Combining its efficient gas exchange abilities, self-repairing function, and biocompatibility, almost full recovery was observed in injured mouse skin within 13 days, highlighting its promising clinical utility.

[Fundamentals and practice of the application of nasal packing in sinonasal surgery]

BACKGROUND AND OBJECTIVES

This paper presents an overview on nasal packing materials which are available in Germany. The current literature is analyzed whether there are robust criteria regarding use nasal packing after sinonasal surgery, whether there are fundamental and proven advantages or disadvantages of products, and what this means in clinical practice.

MATERIALS AND METHODS

Selective literature analysis using the PubMed database (key words "nasal packing", "nasal tamponade", "nasal surgery", "sinonasal surgery", or "sinus surgery"), corresponding text books and resulting secondary literature.

RESULTS AND CONCLUSIONS

Because of systematic methodological shortcomings, the literature does not help in the decision-making about which nasal packing should be used after which kind of sinonasal surgery. In fact, individual approaches for the many different clinical scenarios are recommended. In principle, nasal packing aims in hemostasis, should promote wound healing, and should not result in secondary morbidity. Nasal packing materials should be smooth (non-absorbable materials), inert (absorbable materials), and should not exert excessive pressure. Using non-absorbable packing entails the risk of potentially lethal aspiration and ingestion. For safety reasons inpatient control is recommended as long as this packing is in situ. With other, uncritical packing materials and in patients with special conditions, outpatient control could be justified.

Preparation of pH-responsive oxidized regenerated cellulose hydrogels compounded with nano-ZnO/chitosan/aminocyclodextrin ibuprofen complex for wound dressing

Recently, using oxidized regenerated cellulose (ORC) to build a hydrogel system on promoting healing in wounds has a fast-growing market. However, it remains a challenge to improve the degree of oxidation of regenerated cellulose (RC) and to prepare matrices that are uniquely responsive to the wound environment. Herein, highly oxidized aldehyde-based cellulose from porous RC was prepared by NaBH4-HCl swelling and then NaIO4 oxidation pathway. Chitosan (CS), ethylenediamine-cyclodextrin (EDA-CD) along with ORC have been used to construct hydrogel matrices that are pH-responsive and capable of controlled drug release for use as future wound dressings. And zinc oxide nanoparticles (ZnO NPs) with antimicrobial effect and ibuprofen (IBU) with analgesic effect were piggybacked into the hydrogel system. XRD was used to study the presence of ZnO. SEM was used to observe the surface structure of the prepared hydrogel. TEM was used to observe the particle size of the ZnO NPs. Meanwhile, the oxidation conditions of the ORC were explored. Furthermore, the mechanical, swelling, water retention, cytotoxicity, bacterial inhibition properties and treatment effect, which are closely related to the application of wound dressing, were carefully researched. The unique characteristics of prepared hydrogel, including pH-responsive degradability and sustained release properties of IBU, were also investigated.

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

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

•

Biopolymers possess sound biocompatibility, biodegradability and bioactivity for the design of hemostatic materials.

•

Molecular structure designs including component and chemical modification are summarized from a microscopic perspective.

•

Design of various forms of hemostatic materials is discussed and compared synthetically from a macroscopic perspective.

Water-Swellable Cellulose Nanofiber Aerogel for Control of Hemorrhage from Penetrating Wounds

Uncontrolled hemorrhage from wounds with deep and irregular cavities is short of efficient hemostats. Here we report a citric acid-cross-linked carboxymethyl cellulose nanofiber (CA-CMCNF) aerogel for the control of bleeding from penetrating wounds. The compressed CA-CMCNF aerogel could quickly swell into its original shape in water in seconds. The maximum mass and volume expansion ratios were over 6800 and 3000%, respectively. The water-swellable property allows the aerogel to self-expand and fill in the cavities of wounds. The in situ-generated expansion pressure resisted the systolic blood pressure, and the plentiful carboxyl groups triggered the active coagulation pathway, both contributing to the hemostatic capability of the aerogel. Additionally, the aerogel had good biocompatibility and excellent antibacterial capability. The animal experiments revealed that the aerogels significantly reduced both the hemostasis time and the amount of bleeding in a liver penetrating model. Therefore, this study provides a safe and robust hemostatic aerogel for controlling bleeding from penetrating wounds.

A Review on the Modification of Cellulose and Its Applications

The latest advancements in cellulose and its derivatives are the subject of this study. We summarize the characteristics, modifications, applications, and properties of cellulose. Here, we discuss new breakthroughs in modified cellulose that allow for enhanced control. In addition to standard approaches, improvements in different techniques employed for cellulose and its derivatives are the subject of this review. The various strategies for synthetic polymers are also discussed. The recent advancements in polymer production allow for more precise control, and make it possible to make functional celluloses with better physical qualities. For sustainability and environmental preservation, the development of cellulose green processing is the most abundant renewable substance in nature. The discovery of cellulose disintegration opens up new possibilities for sustainable techniques. Based on the review of recent scientific literature, we believe that additional chemical units of cellulose solubility should be used. This evaluation will evaluate the sustainability of biomass and processing the greenness for the long term. It appears not only crucial to dissolution, but also to the greenness of any process.

Superior Hemostatic and Wound-Healing Properties of Gel and Sponge Forms of Non-Oxidized Cellulose Nanofibers: In Vitro and In Vivo Studies

Many materials have been engineered and commercialized as hemostatic agents. However, there is still a gap in the availability of hemostats that offer biocompatibility and biodegradability in combination with effective hemostatic properties. Cellulose nanofibers were investigated as hemostatic materials with most studies focusing on oxidized cellulose-derived hemostats. Our recent studies demonstrated that by optimizing the morphological properties of non-oxidized cellulose nanofibers (CNFs) enhanced hemostasis is achieved. Herein, we investigate the hemostatic and wound-healing properties of CNFs with optimized morphology using two forms, gel and sponge. In vitro thromboelastometry studies demonstrate that CNFs reduce clotting time by 68% (±SE 2%) and 88% (±SE 5%) in gel and sponge forms, respectively. In an in vivo murine liver injury model, CNFs significantly reduce blood loss by 38% (±SE 10%). The pH-neutral CNFs do not damage red blood cells, nor do they impede the proliferation of fibroblast or endothelial cells. Subcutaneously-implanted CNFs show a foreign body reaction resolving with the degradation of CNFs on histological examination and there is no scarring in the skin after 8 weeks. Demonstrating superior hemostatic performance in a variety of forms, as well as biocompatibility and biodegradability, CNFs hold significant potential for use in surgical and first-aid environments. This article is protected by copyright. All rights reserved.

Effect of naturally derived surgical hemostatic materials on the proliferation of A549 human lung adenocarcinoma cells

Hemostatic materials are generally applied in surgical operations for cancer, but their effects on the growth and recurrence of tumors are unclear. Herein, three commonly used naturally derived hemostatic materials, gelatin sponge, Surgicel (oxidized regenerated cellulose), and biopaper (mixture of sodium hyaluronate and carboxymethyl chitosan), were cocultured with A549 human lung adenocarcinoma cells in vitro. Furthermore, the performance of hemostatic materials and the tumorigenicity of the materials with A549 ​cells were observed after subcutaneous implantation into BALB/c mice. The in vitro results showed that biopaper was dissolved quickly, with the highest cell numbers at 2 and 4 days of culture. Gelatin sponges retained their structure and elicited the least cell infiltration during the 2- to 10-day culture. Surgicel partially dissolved and supported cell growth over time. The in vivo results showed that biopaper degraded rapidly and elicited an acute Th1 lymphocyte reaction at 3 days after implantation, which was decreased at 7 days after implantation. The gelatin sponge resisted degradation and evoked a hybrid M1/M2 macrophage reaction at 7–21 days after implantation, and a protumor M2d subset was confirmed. Surgicel resisted early degradation and caused obvious antitumor M2a macrophage reactions. Mice subjected to subcutaneous implantation of A549 ​cells and hemostatic materials in the gelatin sponge group had the largest tumor volumes and the shortest overall survival (OS), while the Surgicel and the biopaper group had the smallest volumes and the longest OS. Therefore, although gelatin sponges exhibited cytotoxicity to A549 ​cells in vitro, they promoted the growth of A549 ​cells in vivo, which was related to chronic M2d macrophage reaction. Surgicel and biopaper inhibited A549 ​cell growth in vivo, which is associated with chronic M2a macrophage reaction or acute Th1 lymphocyte reaction.

•

The gelatin sponge, Surgicel and biopaper had different effects on A549 ​cell growth and proliferation.

•

Biopaper degraded rapidly in vivo and elicited an antitumor Th1 lymphocyte reaction at acute inflammatory phase.

•

The gelatin sponge resisted degradation and evoked a protumor M2d macrophage reactions.

•

Surgicel resisted early degradation and caused obvious antitumor M2a macrophage reactions.

Evaluation of self-prepared absorbable hemostatic cellulose fibrils

To evaluate the effectiveness and safety of self-prepared absorbable hemostatic fibrils.A kind of absorbable hemostatic fibrils were prepared by self-developed patent technique. The physical form and molecular structure of the fibrils and a marketed product Surgicel were characterized by general observation and infrared spectroscopy; the carboxyl content, pH value and relative molecular mass of fibrils were determined by potentiometric titration method, pH meter and copper ethylenediamine method, respectively. The behavior of the fibrils and Surgicel in contact with blood was observed by inverted microscope, the cytotoxicity was evaluated by agarose diffusion cell assay . The external iliac artery hemorrhage model and the back muscle infiltration model in rats were established. The hemostatic effectiveness of the fibrils was investigated by hemostasis time and blood weight, and the degradation and biosafety of fibrils were investigated by observation photography, immune organ weighing, hematology and coagulation index measuring, and histopathological examination. The fibrils and Surgicel had similar molecular structures. Compared with the raw material regenerated cellulose, the typical carboxyl stretching vibration absorption peak of -COOH appeared near in both fibrils and Surgicel. The carboxyl content of the two materials was about 20%, and the pH value was about 3. The relative molecular mass of the fibers after oxidation was 4466±79, which was close to that of Surgicel(>0.05). After contacting with blood, the volume of fibrils and Surgicel expanded, and absorbed blood of dozens of times as their own weight. The results of agar diffusion test showed that the fibrils had no cytotoxicity. The results of animal experiments showed that the hemostasis completed within and there was no significant difference in blood weight and speed of hemostasis between two products (both >0.05). The fibrils could be degraded 1 week after being implanted to the bleeding sites of the muscle. There were no pathological effects on the appearance, body weight, food intake, immunological tissue thymus, spleen, lymph nodes, hematology and coagulation indexes of the rats, and no obvious abnormality found in the histopathological examination. The prepared absorbable hemostatic fibrils have excellent biological safety and effectiveness.

Recent advancements in cellulose-based biomaterials for management of infected wounds

INTRODUCTION

Chronic wounds are a substantial burden on the healthcare system. Their treatment requires advanced dressings, which can provide a moist wound environment, prevent bacterial infiltration, and act as a drug carrier. Cellulose is biocompatible, biodegradable, and can be functionalized according to specific requirements, which makes it a highly versatile biomaterial. Antimicrobial cellulose dressings are proving to be highly effective against infected wounds.

AREAS COVERED

This review briefly addresses the mechanism of wound healing and its pathophysiology. It also discusses wound infections, biofilm formation, and progressive emergence of drug-resistant bacteria in chronic wounds and the treatment strategies for such types of infected wounds. It also summarizes the general properties, method of production, and types of cellulose wound dressings. It explores recent studies and advancements regarding the use of cellulose and its derivatives in wound management.

EXPERT OPINION

Cellulose and its various functionalized derivatives represent a promising choice of wound dressing material. Cellulose-based dressings loaded with antimicrobials are very useful in controlling infection in a chronic wound. Recent studies showing its efficacy against drug-resistant bacteria make it a favorable choice for chronic wound infections. Further research and large-scale clinical trials are required for better clinical evidence of its efficiency.

Cellulose nanocrystals-based materials as hemostatic agents for wound dressings: a review

Wound dressings are devices used to stop bleeding and provide appropriate environmental conditions to accelerate wound healing. The effectiveness of wound dressing materials can be crucial to prevent deaths from excessive bleeding in surgeries and promote complete restoration of the injury. Some requirements for an ideal wound dressing are rapid hemostatic effect, high swelling capacity, antibacterial properties, biocompatibility, biodegradability, and mechanical strength. However, finding all these properties in a single material remains a challenge. In this context, nanocomposites have demonstrated an excellent capacity for this application because of their multifunctionality. One of the emerging materials used in nanocomposite manufacture is cellulose nanocrystals (CNCs), which are rod-like crystalline nanometric structures present on cellulose chains. These nanoparticles are attractive for wound healing applications because of their high aspect ratio, high mechanical properties, functionality and low density. Hence, this work aimed to present an overview of nanocomposites constituted by CNCs for wound healing applications. The review focuses on the most common materials used as matrices, the types of dressing, and their fabrication techniques. Novel wound dressings composites have improved hemostatic, swelling, and mechanical properties compared to other pure biopolymers while preserving their other biological properties. Films, nanofibers mats, sponges, and hydrogels have been prepared with CNCs nanocomposites, and in vitro and in vivo tests have proved their suitability for wound healing.

Application and outlook of topical hemostatic materials: a narrative review

Bleeding complications can cause significant morbidities and mortalities in both civilian and military conditions. The formation of stable blood clots or hemostasis is essential to prevent major blood loss and death from excessive bleeding. However, the body's self-coagulation process cannot accomplish timely hemostasis without the assistance of hemostatic agents under some conditions. In the past two decades, topical hemostatic materials and devices containing platelets, fibrin, and polysaccharides have been gradually developed and introduced to induce faster or more stable blood clot formation, updating or iterating traditional hemostatic materials. Despite the various forms and functions of topical hemostatic materials that have been developed for different clinical conditions, uncontrolled hemorrhage still causes over 30% of trauma deaths across the world. Therefore, it is important to fabricate fast, efficient, safe, and ready-to-use novel hemostatic materials. It is necessary to understand the coagulation process and the hemostatic mechanism of different materials to develop novel topical hemostatic agents, such as tissue adhesives and sealants from various natural and synthetic materials. This review discusses the structural features of topical hemostatic materials related to the stimulation of hemostasis, summarizes the commercially available products and their applications, and reviews the ongoing clinical trials and recent studies concerning the development of different hemostatic materials.

Hemostatic Dressings Made of Oxidized Bacterial Nanocellulose Membranes

Surgicel® (regenerated oxidized cellulose) is a bio-absorbable hemostatic material widely applied to prevent surgery-derived adhesions. Some critical issues have been reported associated with this biomaterial, which we aimed to overcome by producing bacterial nanocellulose (BNC) membranes with hemostatic activity, through electrochemical oxidation using the tetramethylpiperidine-1-oxyl (TEMPO) radical. Samples were characterized by FTIR, NMR, SEM, XRD and their degree of polymerization. The oxidation degree was evaluated by titration of the carboxyl groups and the hemostatic behavior by whole-blood-clotting assays. In vitro and in vivo biodegradability of oxidized BNC membranes were evaluated and compared with that of Surgicel®. The oxidation degree increased from 4% to 7% and up to 15%, corresponding to an applied charge of 400, 700 and 1200 Coulombs, respectively. The oxidized BNC preserved the crystallinity and the 3D nano-fibrillar network, and demonstrated hemostatic activity, although not as effective as that of Surgicel®. In vivo assays demonstrated that the oxidized membranes did not induce an inflammatory response, revealing a good biocompatibility. However, non-degraded oxidized BNC was still detected at the implantation site after 56 days.

Influence of several biodegradable components added to pure and nanosilver-doped PMMA bone cements on its biological and mechanical properties

Acrylic bone cements (BC) are wildly used in medicine. Despite favorable mechanical properties, processability and inject capability, BC lack bioactivity. To overcome this, we investigated the effects of selected biodegradable additives to create a partially-degradable BC and also we evaluated its combination with nanosilver (AgNp). We hypothesized that using above strategies it would be possible to obtain bioactive BC. The Cemex was used as the base material, modified at 2.5, 5 or 10 wt% with either cellulose, chitosan, magnesium, polydioxanone or tricalcium-phosphate. The resulted modified BC was examined for surface morphology, wettability, porosity, mechanical and nanomechanical properties and cytocompatibility. The composite BC doped with AgNp was also examined for its release and antibacterial properties. The results showed that it is possible to create modified cement and all studied modifiers increased its porosity. Applying the additives slightly decreased BC wettability and mechanical properties, but the positive effect of the additives was observed in nanomechanical research. The relatively poor cytocompatibility of modified BC was attributed to the unreacted monomer release, except for polydioxanone modification which increased cells viability. Furthermore, all additives facilitated AgNp release and increased BC antibacterial effectiveness. Our present studies suggest the optimal content of biodegradable component for BC is 5 wt%. At this content, an improvement in BC porosity is achieved without significant deterioration of BC physical and mechanical properties. Polydioxanone and cellulose seem to be the most promising additives that improve porosity and antibacterial properties of antibiotic or nanosilver-loaded BC. Partially-degradable BC may be a good strategy to improve their antibacterial effectiveness, but some caution is still required regarding their cytocompatibility. STATEMENT OF SIGNIFICANCE: The lack of bone cement bioactivity is the main limitation of its effectiveness in medicine. To overcome this, we have created composite cements with partially-degradable properties. We also modified these cements with nanosilver to provide antibacterial properties. We examined five various additives at three different contents to modify a selected bone cement. Our results broaden the knowledge about potential modifiers and properties of composite cements. We selected the optimal content and the most promising additives, and showed that the combination of these additives with nanosilver would increase cements` antibacterial effectiveness. Such modified cements may be a new solution for medical applications.

Fabrication of oxidized bacterial cellulose by nitrogen dioxide in chloroform/cyclohexane as a highly loaded drug carrier for sustained release of cisplatin

Carboxylated bacterial cellulose (OBC) was fabricated by oxidation with nitrogen dioxide in chloroform/cyclohexane and employed as a carrier for sustained release of antitumor substance cisplatin (CDDP). The influence of removing water method, solvent used in the synthesis, concentration of N₂O₄, and duration of the oxidation on content of carboxyl groups in reaction products was established. Due to the possibility of nitrogen dioxide to penetrate into cellulose crystallites, the carboxyl group content of the OBC reaches high values up to 4 mmol/g. In vitro degradation of OBC was determined under simulated physiological conditions. The immobilization of CDDP on OBC was studied in detail. The initial burst release of the drug from the polymer was depressed. The cytotoxicity of CDDP-loaded OBC was evaluated with HeLa cells. The unique structure and properties of OBC make it a great candidate as drug delivery carrier.

Oxidized cellulose-based hemostatic materials

The application of hemostatic agents is essential to prevent significant blood loss and death from excessive bleeding in surgical or emergency scenarios. Oxidized cellulose is an excellent biodegradable and biocompatible derivate of cellulose, which has become one of the most important hemostatic agents used in surgical procedures. However, to date, there has been no comprehensive report assessing oxidized cellulose-based hemostatic materials. Hence, this paper first reviewed the oxidation preparation, cellulose origin and structure, as well as biodegradability and safety of oxidized cellulose. Then a comprehensive review regarding the hemostatic mechanisms, various forms, modification, and current commercially available products of oxidized cellulose is discussed, which emphatically presents the most significant developments in the recent scientific literature. In conclusion, this paper summarizes the latest developments in oxidized cellulose-based hemostatic materials and provides a reference for further research and development in this field.