Alginate dressings in surgery and wound management--Part 1

A macromolecular cross-linked alginate aerogel with excellent concentrating effect for rapid hemostasis

Alginate-based materials present promising potential for emergency hemostasis due to their excellent properties, such as procoagulant capability, biocompatibility, low immunogenicity, and cost-effectiveness. However, the inherent deficiencies in water solubility and mechanical strength pose a threat to hemostatic efficiency. Here, we innovatively developed a macromolecular cross-linked alginate aerogel based on norbornene- and thiol-functionalized alginates through a combined thiol-ene cross-linking/freeze-drying process. The resulting aerogel features an interconnected macroporous structure with remarkable water-uptake capacity (approximately 9000 % in weight ratio), contributing to efficient blood absorption, while the enhanced mechanical strength of the aerogel ensures stability and durability during the hemostatic process. Comprehensive hemostasis-relevant assays demonstrated that the aerogel possessed outstanding coagulation capability, which is attributed to the synergistic impacts on concentrating effect, platelet enrichment, and intrinsic coagulation pathway. Upon application to in vivo uncontrolled hemorrhage models of tail amputation and hepatic injury, the aerogel demonstrated significantly superior performance compared to commercial alginate hemostatic agent, yielding reductions in clotting time and blood loss of up to 80 % and 85 %, respectively. Collectively, our work illustrated that the alginate porous aerogel overcomes the deficiencies of alginate materials while exhibiting exceptional performance in hemorrhage, rendering it an appealing candidate for rapid hemostasis.

Challenges and Prospects of Development of Herbal Biomaterial Based Ethical Wound Care Products-A Scoping Review

Total wound care is an unmet therapeutic need considering the morbidity and mortality associated with the rising prevalence of nonhealing/chronic wounds. Current wound management fails to address all aspects/types of wounds despite the availability of scores of traditional and modern, investigational products. Traditional medicine drugs of wound healing repute validated to target multiple biological pathways and key events in the mammalian wound healing cascade, reportedly affecting wound healing phases. Advances in the development of biocomposite matrices and their analytical characterization warrant a relook at consolidating time-tested wound healing properties of herbal bioactives for prospective development as ethical wound care products. Aside from the bottlenecks of their multiconstituent profiling and clinical trial data generation, regulatory hurdles also cloister any systematic attempts at their re-engineering into clinical deliverables. In the context of national policy changes to bring in totally indigenous solutions, countries with a huge knowledge/material resource on wound healing bioactives need to essentially facilitate the same.

Plus moist HS-W®: a new nasal packing material for the middle meatus in endoscopic sinus surgery

PURPOSE

Removal of the current calcium alginate packing materials to the middle meatus in endoscopic sinus surgery (ESS) is usually accompanied by discomfort or pain owing to the hard and brittle nature of these materials. Plus moist HS-W® is a new calcium alginate packing material released in 2022 developed to overcome this issue by changing the uronic acid component. We aimed to compare the discomfort/pain during the removal of Plus moist HS-W® with Kaltostat®, as well as their suitability as packing materials in ESS.

METHODS

Kaltostat® and Plus moist HS-W® were used as packing materials in 22 and 21 patients who underwent ESS in 2021 and 2022, respectively. Patients were asked to rate the pain during the packing removal 10 days after ESS using the Numerical Rating Scale (NRS). The ratio of residual packing materials, number of suctions (insertions/extractions of the suction cannula), and time required to remove packing materials were measured. Postoperative complications such as hemorrhage, local infection, lateralization of the middle turbinate, and synechia of the middle meatus were also evaluated.

RESULTS

The Plus moist HS-W® group exhibited significantly lower NRS pain scores, a lower ratio of residual packing materials, a reduced number of suctions, and a shorter time required to remove the packing. No obvious postoperative complications occurred in both groups except for one suspicious case of a slight infection in the Kaltostat® group.

CONCLUSION

Compared with Kaltostat®, Plus moist HS-W®, characterized by better gelatinization than Kaltostat®, benefits patients by minimizing discomfort/pain during removal.

LEVEL OF EVIDENCE

Level 3.

The unexplored role of alkali and alkaline earth elements (ALAEs) on the structure, processing, and biological effects of bioactive glasses

Bioactive glass has been employed in several medical applications since its inception in 1969. The compositions of these materials have been investigated extensively with emphasis on glass network formers, therapeutic transition metals, and glass network modifiers. Through these experiments, several commercial and experimental compositions have been developed with varying chemical durability, induced physiological responses, and hydroxyapatite forming abilities. In many of these studies, the concentrations of each alkali and alkaline earth element have been altered to monitor changes in structure and biological response. This review aims to discuss the impact of each alkali and alkaline earth element on the structure, processing, and biological effects of bioactive glass. We explore critical questions regarding these elements from both a glass science and biological perspective. Should elements with little biological impact be included? Are alkali free bioactive glasses more promising for greater biological responses? Does this mixed alkali effect show increased degradation rates and should it be employed for optimized dissolution? Each of these questions along with others are evaluated comprehensively and discussed in the final section where guidance for compositional design is provided.

Bioarchitectural Design of Bioactive Biopolymers: Structure-Function Paradigm for Diabetic Wound Healing

Chronic wounds such as diabetic ulcers are a major complication in diabetes caused by hyperglycemia, prolonged inflammation, high oxidative stress, and bacterial bioburden. Bioactive biopolymers have been found to have a biological response in wound tissue microenvironments and are used for developing advanced tissue engineering strategies to enhance wound healing. These biopolymers possess innate bioactivity and are biodegradable, with favourable mechanical properties. However, their bioactivity is highly dependent on their structural properties, which need to be carefully considered while developing wound healing strategies. Biopolymers such as alginate, chitosan, hyaluronic acid, and collagen have previously been used in wound healing solutions but the modulation of structural/physico-chemical properties for differential bioactivity have not been the prime focus. Factors such as molecular weight, degree of polymerization, amino acid sequences, and hierarchical structures can have a spectrum of immunomodulatory, anti-bacterial, and anti-oxidant properties that could determine the fate of the wound. The current narrative review addresses the structure-function relationship in bioactive biopolymers for promoting healing in chronic wounds with emphasis on diabetic ulcers. This review highlights the need for characterization of the biopolymers under research while designing biomaterials to maximize the inherent bioactive potency for better tissue regeneration outcomes, especially in the context of diabetic ulcers.

Pioneering a paradigm shift in tissue engineering and regeneration with polysaccharides and proteins-based scaffolds: A comprehensive review

In the realm of modern medicine, tissue engineering and regeneration stands as a beacon of hope, offering the promise of restoring form and function to damaged or diseased organs and tissues. Central to this revolutionary field are biological macromolecules-nature's own blueprints for regeneration. The growing interest in bio-derived macromolecules and their composites is driven by their environmentally friendly qualities, renewable nature, minimal carbon footprint, and widespread availability in our ecosystem. Capitalizing on these unique attributes, specific composites can be tailored and enhanced for potential utilization in the realm of tissue engineering (TE). This review predominantly concentrates on the present research trends involving TE scaffolds constructed from polysaccharides, proteins and glycosaminoglycans. It provides an overview of the prerequisites, production methods, and TE applications associated with a range of biological macromolecules. Furthermore, it tackles the challenges and opportunities arising from the adoption of these biomaterials in the field of TE. This review also presents a novel perspective on the development of functional biomaterials with broad applicability across various biomedical applications.

Marine-derived polysaccharides and their therapeutic potential in wound healing application - A review

Polysaccharides originating from marine sources have been studied as potential material for use in wound dressings because of their desirable characteristics of biocompatibility, biodegradability, and low toxicity. Marine-derived polysaccharides used as wound dressing, provide several benefits such as promoting wound healing by providing a moist environment that facilitates cell migration and proliferation. They can also act as a barrier against external contaminants and provide a protective layer to prevent further damage to the wound. Research studies have shown that marine-derived polysaccharides can be used to develop different types of wound dressings such as hydrogels, films, and fibres. These dressings can be personalised to meet specific requirements based on the type and severity of the wound. For instance, hydrogels can be used for deep wounds to provide a moist environment, while films can be used for superficial wounds to provide a protective barrier. Additionally, these polysaccharides can be modified to improve their properties, such as enhancing their mechanical strength or increasing their ability to release bioactive molecules that can promote wound healing. Overall, marine-derived polysaccharides show great promise for developing effective and safe wound dressings for various wound types.

In Situ Hydrogel Formulation for Advanced Wound Dressing: Influence of Co-Solvents and Functional Excipient on Tailored Alginate-Pectin-Chitosan Blend Gelation Kinetics, Adhesiveness, and Performance

Chronic skin wounds affect more than 40 million patients worldwide, representing a huge problem for healthcare systems. This study elucidates the optimization of an in situ gelling polymer blend powder for biomedical applications through the use of co-solvents and functional excipients, underlining the possibility of tailoring microparticulate powder properties to generate, in situ, hydrogels with advanced properties that are able to improve wound management and patient well-being. The blend was composed of alginate, pectin, and chitosan (APC). Various co-solvents (ethanol, isopropanol, and acetone), and salt excipients (sodium bicarbonate and ammonium carbonate) were used to modulate the gelation kinetics, rheology, adhesiveness, and water vapor transmission rate of the gels. The use of co-solvents significantly influenced particle size (mean diameter ranging from 2.91 to 5.05 µm), depending on the solvent removal rate. Hydrogels obtained using ethanol were able to absorb over 15 times their weight in simulated wound fluid within just 5 min, whereas when sodium bicarbonate was used, complete gelation was achieved in less than 30 s. Such improvement was related to the internal microporous network typical of the particle matrix obtained with the use of co-solvents, whereas sodium bicarbonate was able to promote the formation of allowed particles. Specific formulations demonstrated an optimal water vapor transmission rate, enhanced viscoelastic properties, gel stiffness, and adhesiveness (7.7 to 9.9 kPa), facilitating an atraumatic removal post-use with minimized risk of unintended removal. Microscopic analysis unveiled that porous inner structures were influencing fluid uptake, gel formation, and transpiration. In summary, this study provided valuable insights for optimizing tailored APC hydrogels as advanced wound dressings for chronic wounds, including vascular ulcers, pressure ulcers, and partial and full-thickness wounds, characterized by a high production of exudate.

The emerging progress on wound dressings and their application in clinic wound management

BACKGROUND

In addition to its barrier function, the skin plays a crucial role in maintaining the stability of the body's internal environment and normal physiological functions. When the skin is damaged, it is important to select proper dressings as temporary barriers to cover the wound, which can exert significant effects on defence against microbial infection, maintaining normal tissue/cell functions, and coordinating the process of wound repair and regeneration. It now forms an important approach in clinic practice to facilitate wound repair.

SEARCH STRATEGIES

We conducted a comprehensive literature search using online databases including PubMed, Web of Science, MEDLINE, ScienceDirect, Wiley Online Library, CNKI, and Wanfang Data. In addition, information was obtained from local and foreign books on biomaterials science and traumatology.

RESULTS

This review focuses on the efficacy and principles of functional dressings for anti-bacteria, anti-infection, anti-inflammation, anti-oxidation, hemostasis, and wound healing facilitation; and analyses the research progress of dressings carrying living cells such as fibroblasts, keratinocytes, skin appendage cells, and stem cells from different origins. We also summarize the recent advances in intelligent wound dressings with respect to real-time monitoring, automatic drug delivery, and precise adjustment according to the actual wound microenvironment. In addition, this review explores and compares the characteristics, advantages and disadvantages, mechanisms of actions, and application scopes of dressings made from different materials.

CONCLUSION

The real-time and dynamic acquisition and analysis of wound conditions are crucial for wound management and prognostic evaluation. Therefore, the development of modern dressings that integrate multiple functions, have high similarity to the skin, and are highly intelligent will be the focus of future research, which could drive efficient wound management and personalized medicine, and ultimately facilitate the translation of health monitoring into clinical practice.

Natural and Synthetic Polymeric Biomaterials for Application in Wound Management

Biomaterials are at the forefront of the future, finding a variety of applications in the biomedical field, especially in wound healing, thanks to their biocompatible and biodegradable properties. Wounds spontaneously try to heal through a series of interconnected processes involving several initiators and mediators such as cytokines, macrophages, and fibroblasts. The combination of biopolymers with wound healing properties may provide opportunities to synthesize matrices that stimulate and trigger target cell responses crucial to the healing process. This review outlines the optimal management and care required for wound treatment with a special focus on biopolymers, drug-delivery systems, and nanotechnologies used for enhanced wound healing applications. Researchers have utilized a range of techniques to produce wound dressings, leading to products with different characteristics. Each method comes with its unique strengths and limitations, which are important to consider. The future trajectory in wound dressing advancement should prioritize economical and eco-friendly methodologies, along with improving the efficacy of constituent materials. The aim of this work is to give researchers the possibility to evaluate the proper materials for wound dressing preparation and to better understand the optimal synthesis conditions as well as the most effective bioactive molecules to load.

Hyaluronic acid/alginate-based biomimetic hydrogel membranes for accelerated diabetic wound repair

The study aims to develop a new multifunctional biopolymer-based hydrogel membrane dressing by adopting a solvent casting method for the controlled release of cefotaxime sodium at the wound site. Sodium alginate enhances collagen production in the skin, which provides tensile strength to healing tissue. Moreover, the significance of extracellular molecules such as hyaluronic acid in the wound the healing cascade renders these biopolymers an essential ingredient for the fabrication of hydrogel membranes via physical crosslinking (hydrogen bonding). These membranes were further investigated in terms of their structure, and surface morphology, as well as cell viability analysis. A membrane with the most suitable characteristics was chosen as a candidate for cefotaxime sodium loading and in vivo analysis. Results show that the 3D porous nature of developed membranes allows optimum water vapor and oxygen transmission (>8.21 mg/mL) to divert excessive wound exudate away from the diabetic wound bed, MTT assay confirmed cell viability at more than 80%. In vivo results confirmed that the CTX-HA-Alg-PVA hydrogel group showed rapid wound healing with accelerated re-epithelization and a decreased inflammatory response. Conclusively, these findings indicate that CTX-HA-Alg-PVA hydrogel membranes exhibit a suitable niche for use as dressing membranes for healing of diabetic wounds.

Bio-based polymers containing traditional medicinal fillers for wound healing applications - An evaluation of neoteric development and future perspectives

In recent years, health-care providers have seen more patients with difficult-to-treat wounds and burns. The biopolymer-based wound dressing protects the wounded area while assisting in the recovery of dermal and epithelial tissues throughout the healing process. The overall number of patients with chronic lesions has been expanding due to developing society, over weight, and cardiovascular illness. For the treatment of chronic wounds, there is an increasing demand for the development of ideal wound dressing materials with excellent properties such as antibacterial activity, biocompatibility, free radical scavenging capacity, non-adherent property, hydrophilicity, and so on. Nevertheless, owing to the above mention properties, natural polymers are being used for several key functions of biomedicine like narcotic distribution systems, tissue manufacturing, bandages, and so on. Accordingly, the significance of these bio-based polymers interfered with healing functions that lead to informing and inspiring youth and scientist researchers worldwide to grab with these far-reaching areas of medicine and biology. The review highlights the physiochemical properties of natural polymers, the biological evaluation of various materials as wound dressings, their synthesis and mechanical properties, clinical status, challenges, and future perspectives.

Maximizing Postoperative Recovery: The Role of Functional Biomaterials as Nasal Packs-A Comprehensive Systematic Review without Meta-Analysis (SWiM)

Numerous biomaterials have been developed over the years to enhance the outcomes of endoscopic sinus surgery (ESS) for patients with chronic rhinosinusitis. These products are specifically designed to prevent postoperative bleeding, optimize wound healing, and reduce inflammation. However, there is no singular material on the market that can be deemed the optimal material for the nasal pack. We systematically reviewed the available evidence to assess the functional biomaterial efficacy after ESS in prospective studies. The search was performed using predetermined inclusion and exclusion criteria, and 31 articles were identified in PubMed, Scopus, and Web of Science. The Cochrane risk-of-bias tool for randomized trials (RoB 2) was used to assess each study's risk of bias. The studies were critically analyzed and categorized into types of biomaterial and functional properties, according to synthesis without meta-analysis (SWiM) guidelines. Despite the heterogeneity between studies, it was observed that chitosan, gelatin, hyaluronic acid, and starch-derived materials exhibit better endoscopic scores and significant potential for use in nasal packing. The published data support the idea that applying a nasal pack after ESS improves wound healing and patient-reported outcomes.

Chitosan, alginate, hyaluronic acid and other novel multifunctional hydrogel dressings for wound healing: A review

Wound healing is a complex project, and effectively promoting skin repair is a huge clinical challenge. Hydrogels have great prospect in the field of wound dressings because their physical properties are very similar to those of living tissue and have excellent properties such as high water content, oxygen permeability and softness. However, the single performance of traditional hydrogels limits their application as wound dressings. Therefore, natural polymers such as chitosan, alginate and hyaluronic acid, which are non-toxic and biocompatible, are individually or combined with other polymer materials, and loaded with typical drugs, bioactive molecules or nanomaterials. Then, the development of novel multifunctional hydrogel dressings with good antibacterial, self-healing, injectable and multi-stimulation responsiveness by using advanced technologies such as 3D printing, electrospinning and stem cell therapy has become a hot topic of current research. This paper focuses on the functional properties of novel multifunctional hydrogel dressings such as chitosan, alginate and hyaluronic acid, which lays the foundation for the research of novel hydrogel dressings with better performance.

Recent advances of antibacterial starch-based materials

Starch has attracted a lot of attention because it is biodegradable, renewable, nontoxic and low cost. By adding antibacterial substances to starch, starch-based materials have antibacterial properties. The composite with other materials can improve the comprehensive performance of starch-based materials, thus broadening the application field of the material. In this paper, we focus on antibacterial starch-based materials and review their preparation and applications. It was found that antibacterial starch-based materials were most widely used in packaging, followed by medicine, and the research on smart starch-based materials was relatively less. This review may provide some reference value for subsequent studies of starch-based materials.

Multifunctionalized alginate/polydopamine cryogel for hemostasis, antibacteria and promotion of wound healing

Hemostasis and anti-infection are crucial for emergency treatment of severe trauma. Developing functional biomaterial with efficient hemostasis, antibacterial activity and wound healing is of great social significance and clinical value to fast stop bleeding and save lives, but it is still challenged. Here we designed a series of multifunctionalized SA/PDA cryogels by using two-step cross-linking of dopamine and sodium alginate. The resulting interpenetrating network structure had good swelling ratio, excellent mechanical and shape memory properties. Compared with cotton gauze and gelatin sponge, the cryogels exhibited excellent activation of coagulation cascade, more blood cells and platelet adhesion. Due to the action of polydopamine, the cryogel also showed good antioxidant activity and photothermal antibacterial ability assisted by near-infrared radiation, as well as better wound healing performance than gelatin sponge and Tegaderm™ film. Moreover, in the tests of mouse tail docking model, rat femoral artery hemostasis model and non-compressible rabbit liver defect model, the treatment by SA/PDA cryogels presented less blood loss and shorter hemostasis time than cotton gauze and gelatin sponge. Therefore, SA/PDA cryogels with simple preparation process, low cost, and good biocompatibility would be applied in the variety of great clinical applications in bleeding control, anti-infection and wound healing, etc.

Polysaccharide-based hydrogels for drug delivery and wound management: a review

INTRODUCTION

Polysaccharide-based hydrogels (PBHs) offer several advantages over their synthetic counterparts. Their natural origin contributes to their nontoxicity, high biocompatibility, and in vivo biodegradability. Their properties can be tuned finely to obtain hydrogels with desired mechanical, structural, and chemical properties.

AREAS COVERED

Such versatile characteristics have potentiated the use of PBHs for the delivery of drugs, vaccines, protein and peptide therapeutics, genes, cells, probiotics, bacteriophages, and other therapeutic agents. Recent advances in hydrogel-based formulations such as nanogels, microgels, microneedles, hydrogel beads, nanocarrier-loaded hydrogels, and complexation hydrogels have enabled the precise delivery of a wide range of therapeutics. This review aims to give a holistic overview of hydrogels in the delivery of a variety of therapeutics through different routes.

EXPERT OPINION

PBHs have been used to enable the oral delivery of vaccines and other biologicals, thereby allowing self-administration of life-saving vaccines during public health emergencies. There is a lack of commercialized wound dressings for the treatment of chronic wounds. PBH-based wound dressings, especially those based on chitosan and loaded with actives and growth factors, have the potential to help in the long-term treatment of such wounds. Recent developments in the 3D printing of hydrogels can enable the quick and large-scale production of drug-loaded hydrogels.

Exploration of Dual Ionic Cross-Linked Alginate Hydrogels Via Cations of Varying Valences towards Wound Healing

This study explored the synergistic effects of simultaneously using calcium and gallium cations in the cross-linking of alginate, detailing its effects on the characteristics of alginate compared to its single cation counterparts. The primary goal is to determine if there are any synergistic effects associated with the utilisation of multiple multivalent cations in polymer cross-linking and whether or not it could therefore be used in pharmaceutical applications such as wound healing. Given the fact divalent and trivalent cations have never been utilised together for cross-linking, an explanation for the mode of binding that occurs between the alginate and the cations during the cross-linking process and how it may affect the future applications of the polymer has been investigated. The calcium gallium alginate polymers were able to retain the antibacterial effects of gallium within the confines of the polymer matrix, possessing superior rheological properties, 6 times that of pure calcium and pure gallium, coupled with an improved swelling capacity that is 4 times higher than that of gallium alginate.

Evaluating polymeric biomaterials to improve next generation wound dressing design

Wound healing is a dynamic series of interconnected events with the ultimate goal of promoting neotissue formation and restoration of anatomical function. Yet, the complexity of wound healing can often result in development of complex, chronic wounds, which currently results in a significant strain and burden to our healthcare system. The advancement of new and effective wound care therapies remains a critical issue, with the current therapeutic modalities often remaining inadequate. Notably, the field of tissue engineering has grown significantly in the last several years, in part, due to the diverse properties and applications of polymeric biomaterials. The interdisciplinary cohesion of the chemical, biological, physical, and material sciences is pertinent to advancing our current understanding of biomaterials and generating new wound care modalities. However, there is still room for closing the gap between the clinical and material science realms in order to more effectively develop novel wound care therapies that aid in the treatment of complex wounds. Thus, in this review, we discuss key material science principles in the context of polymeric biomaterials, provide a clinical breadth to discuss how these properties affect wound dressing design, and the role of polymeric biomaterials in the innovation and design of the next generation of wound dressings.

Alginate dressings continuously for fourteen days on uncontaminated, superficial, partial thickness burns

Calcium alginate dressings are commonly used on split-thickness skin donor sites, where they are typically removed after 14 days. Alginates have been used previously on superficial, partial thickness burns, but changed every 3-4 days. In this study, alginates were applied to superficial, partial thickness burns on adults within 36 hours of injury, then left intact for up to 14 days. Wound healing (≥95% wound epithelialisation) and pain were measured. Twenty-one burns were reviewed on ten patients. Per the initial protocol, six patients were reviewed every 3-5 days, with removal of only secondary dressings, until day 13-14, when the alginate dressings were removed. One patient was reviewed every 3-5 days until day 10, when a clinic nurse removed the alginate dressing. Restrictions on movement during the COVID pandemic necessitated a protocol change, with only one review at approximately day 14 for removal of alginate and secondary dressings; three patients were reviewed in this manner. Burns on all patients were 100% epithelialised at the time of final review and there were no complications, such as scarring, infection, or need for grafting. Following initial debridement and dressings, patients reported minimal pain. Dressing costs appeared to be significantly decreased. This protocol may be particularly useful for patients managed in rural and remote locations, with telemedicine support if required.

Alginate-Based Bio-Composites and Their Potential Applications

Over the last two decades, bio-polymer fibers have attracted attention for their uses in gene therapy, tissue engineering, wound-healing, and controlled drug delivery. The most commonly used bio-polymers are bio-sourced synthetic polymers such as poly (glycolic acid), poly (lactic acid), poly (e-caprolactone), copolymers of polyglycolide and poly (3-hydroxybutyrate), and natural polymers such as chitosan, soy protein, and alginate. Among all of the bio-polymer fibers, alginate is endowed with its ease of sol–gel transformation, remarkable ion exchange properties, and acid stability. Blending alginate fibers with a wide range of other materials has certainly opened many new opportunities for applications. This paper presents an overview on the modification of alginate fibers with nano-particles, adhesive peptides, and natural or synthetic polymers, in order to enhance their properties. The application of alginate fibers in several areas such as cosmetics, sensors, drug delivery, tissue engineering, and water treatment are investigated. The first section is a brief theoretical background regarding the definition, the source, and the structure of alginate. The second part deals with the physico-chemical, structural, and biological properties of alginate bio-polymers. The third part presents the spinning techniques and the effects of the process and solution parameters on the thermo-mechanical and physico-chemical properties of alginate fibers. Then, the fourth part presents the additives used as fillers in order to improve the properties of alginate fibers. Finally, the last section covers the practical applications of alginate composite fibers.

Microencapsulated sodium fusidate to impart antibacterial properties into cotton dressings for traumatic wounds

This research aimed to investigate the use of microencapsulated sodium fusidate to impart antibacterial properties into conventional cotton gauze used to treat traumatic wounds. The microcapsules were prepared with sodium fusidate dissolved in ethanol as the active substance (core) and calcium alginate as the wall material (shell) using an electrospraying method. The microcapsules were then loaded into a 1% solution of chitosan, and conventional sterile cotton gauze fabric was impregnated in this suspension and dried at room temperature. The microcapsules obtained were examined with Fourier transform infrared spectroscopy to confirm the constituents, and by scanning electron microscopy to examine the size and distribution of the microcapsules. The results showed that microcapsules with sodium fusidate as the core material were produced in a size range of 50-200µm. The antibacterial properties of these gauze samples were tested for resistance to both Gram-positive and Gram-negative bacteria. The samples showed antibacterial properties against Gram-positive bacteria (Staphylococcus aureus) only, with an average inhibition zone of 31.67±2.89mm in diameter. The antibacterial effect of the treated gauze samples was tested after washing to investigate the strength of the binding agent, to find out whether the samples maintained antibacterial properties after two hand-rubbed washes. Its absorption capacity, rate of absorbency and air permeability values were 555±4.51%, 1.25±0.04 seconds and 408±2.65cm³/cm²/seconds, respectively. The research findings have established the possibility of imparting antibacterial properties into sterile cotton gauze using microencapsulation of sodium fusidate.

Preparation of Teucrium polium extract-loaded chitosan-sodium lauryl sulfate beads and chitosan-alginate films for wound dressing application

This study aimed to formulate sodium lauryl sulfate cross-linked chitosan beads and sodium alginate-chitosan films for designing a dressing that would shorten the healing time of skin wounds. Teucrium polium extract-loaded chitosan-sodium lauryl sulfate beads (CH-SLS) and chitosan-alginate (CH-ALG) films were prepared and characterized by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). The swelling properties of the CH-SLS beads were also analyzed in a water solution. The obtained Teucrium polium extract-loaded CH-SLS beads and CH-ALG films (TBF) were further incorporated into the commercial adhesive dressing. This TBF wound dressing was then investigated for evaluation of its wound healing potential in the mice using the excision wound model. Healing was assessed by the macroscopic appearance and the rate of wound contraction during 8 days. On day 4, the TBF-treated wounds exhibited 98% reduction in the wound area when they were compared with healing ointment, elastic adhesive dressing, and untreated wounds which were exhibited 63%, 43%, and 32%, respectively. Furthermore, the application of TBF dressing reduced skin wound rank scores and increased the percentage of wounds contraction. These results demonstrate that TBF dressing improves considerably the healing rate and the macroscopic wound appearance at a short delay and this application may have therapeutic benefits in wound healing.

Wound Healing and Therapy in Soft Tissue Defects of the Hand and Foot from a Surgical Point of View

Wounds and tissue defects of the hand and foot often lead to severe functional impairment of the affected extremity. Next to general principles of wound healing, special functional and anatomic considerations must be taken into account in the treatment of wounds in these anatomical regions to achieve a satisfactory reconstructive result. In this article, we outline the concept of wound healing and focus on the special aspects to be considered in wounds of the hand and foot. An overview of different treatment and dressing techniques is given with special emphasis on the reconstruction of damaged structures by plastic surgical means.

Undressing the choice of dressings

There is a vast number of wound dressings to choose from, which can make selecting the most suitable dressing for a wound a daunting prospect. This article highlights how the wound can guide the doctor's decision. Although all wound dressings are intended to achieve optimal wound healing and protection from contamination, they do so to varying degrees depending on the qualities of the dressing and the wound itself. This article looks at a range of dressings, from traditional to newer dressings, and evaluates their benefits and contraindications to help determine where they are best suited for use in wound management.

Effect of Sodium Alginate on Gastrointestinal Symptoms after Esophagogastroduodenoscopy with Biopsy: Randomized Controlled Trial

Background/Aims

After esophagogastroduodenoscopy (EGD) with biopsy, some patients experience gastrointestinal symptoms. This study investigated the effect of sodium alginate on biopsy-related gastrointestinal symptoms.

Methods

In this open-label, randomized, controlled trial, patients undergoing EGD with biopsy were randomly assigned to a treatment or control group. In the treatment group, sodium alginate was orally administered for 3 days after EGD. Patients completed questionnaires about their gastrointestinal symptoms at baseline (past week), the day after returning home, and after another 3 days. Gastrointestinal symptoms, including abdominal pain, epigastric pain/soreness, heartburn, acid reflux, nausea/vomiting, borborygmus, abdominal distension, and belching, were rated using an upper gastrointestinal symptom rating scale (GSRS).

Results

A total of 210 persons (138 men) who underwent EGD with biopsy were enrolled and allocated to the treatment (n=104) or control (n=106) group. At baseline, the demographic factors and GSRS scores were not different between the control and treatment groups. The epigastric pain/soreness score increased in the control group after endoscopic biopsy (+0.056), whereas the score was decreased in the treatment group (-0.067) (p=0.042). In the treatment group, the scores for acid regurgitation and epigastric soreness decreased during follow-up from those at baseline (p<0.05), whereas there were no significant reductions in the control group. The scores for belching and borborygmus decreased during follow-up only in the treatment group. Abdominal bloating decreased in both the control and treatment groups.

Conclusions

Sodium alginate reduced epigastric pain/soreness after EGD with biopsy. Therefore, the prescription of sodium alginate should be considered after endoscopic biopsy.

A tale of two alginates

BACKGROUND

All fibrous wound dressings are considered to have the same action and value to the support of wound healing. Although clear distinction has been accepted between cotton gauze and calcium alginates, there is still no formally recognised distinction between calcium alginates and the more rapidly gelling fibre dressings.

METHOD

Scientific and clinical evaluations were used to differentiate two different fibrous wound care products. One is derived from polymer extraction of algae (alginate dressings); the other has been manufactured from a uniquely patented carboxymethylation process that produces 100% carboxymethyl cellulose (CMC)-based dressings. Structural differences between these dressings were evaluated with respect to three important areas of wound care management: optimal wound moisture control; the ability to reduce risk of complication by locking away harmful components (e.g. bacteria); and reducing the overall cost of wound care by promoting more efficient use of nursing time.

RESULTS

Clear differentiation was illustrated through both scientific and clinical evaluations.

CONCLUSION

This study supports the potential advantages of using a technically advanced fibrous wound dressing over the traditional fibrous alginate wound care product.

Improved drug delivery and accelerated diabetic wound healing by chondroitin sulfate grafted alginate-based thermoreversible hydrogels

Injectable hydrogels with multifunctional tunable properties comprising biocompatibility, anti-oxidative, anti-bacterial, and/or anti-infection are highly preferred to efficiently promote diabetic wound repair and its development remains a challenge. In this study, we report chondroitin sulphate (CS) and sodium alginate (SA)-based injectable hydrogel using solvent casting method loaded with curcumin that could potentiate reepithelization, increase angiogenesis, and collagen deposition at wound microenvironment to endorse healing cascade. The physical interaction and self-assembly of chondroitin sulfate grafted alginate (CS-Alg-g-PF127) hydrogel were confirmed using nuclear magnetic resonance (¹H NMR) and Fourier transformed infrared spectroscopy (FT-IR), and cytocompatibility was confirmed by fibroblast viability assay. The Masson's trichrome (MT) and hematoxylin and eosin (H&E) results revealed that blank chondroitin sulfate grafted alginate (CS-Alg-g-PF127) and CUR loaded CS-Alg-g-PF127 hydrogel had promising tissue regenerative ability, and showing enhanced wound healing compared to other treatment groups. The controlled release of CUR from injectable hydrogel was evaluated by drug release studies and pharmacokinetic profile (PK) using high-performance liquid chromatography (HPLC) that exhibited the mean residence time (MRT) and area under the curve (AUC) was increased up to 16.18 h and 203.64 ± 30.1 μg/mL*h, respectively. Cytotoxicity analysis of the injectable hydrogels using 3 T3-L1 fibroblasts cells and in vivo toxicity evaluated by subcutaneous injection for 24 h followed by histological examination, confirmed good biocompatibility of CUR loaded CS-Alg-g-PF127 hydrogel. Interestingly, the results of in vivo wound healing by injectable hydrogel showed the upregulation of fibroblasts-like cells, collagen deposition, and differentiated keratinocytes stimulating dermo-epidermal junction, which might endorse that they are potential candidates for excisional wound healing models.

Tissue factor-loaded collagen/alginate hydrogel beads as a hemostatic agent

Uncontrolled hemorrhage accounts for a significant proportion of annual mortality worldwide. The development of bioinspired hemostatic composites can effectively reduce hemorrhage and related deaths. This work aims to develop an efficient hemostatic agent by incorporating tissue factor (TF) integrated liposomes and collagen, which are capable of augmenting different inherent hemostatic mechanisms, into hemostasis-stimulating alginate matrix. The composite of TF, collagen and alginate (TCA) was made into hydrogel beads with a diameter range of 2.5-3.5 mm, followed by electron microscopy, infrared spectroscopy, rheological, and swelling characterization to confirm its composition and hydrogel nature. When the TCA beads were introduced into simulated body fluid, a controlled release of the loaded TF-liposomes was observed, which also accelerated with the increase of temperature, obtaining intact free proteoliposomes as demonstrated by fluorescence measurement. It is further seen that TCA beads induced the coagulation of whole rabbit blood in about 4.5 min, as compared to ~14.4 min for the control with only recalcified blood. The lipidated TF, collagen and alginate in TCA beads showed a positive synergistic effect on coagulation, while among them a decreasing procoagulant effect was observed. Finally, we demonstrated by a live/dead cell assay that TCA particles had undetectable cytotoxicity. Thus, the TCA hydrogel macrobeads may offer a potential platform for the development of potent hemostatic agents.

[ALGINATE versus negative-pressure therapy: Comparison of the clinical effectiveness, tolerance and costs in management of patients after surgical excision. Multicenter, randomized non-inferiority clinical trial on 113 patients]

INTRODUCTION

Pure calcium alginate dressing (ALGINATE) and Negative Pressure Wound Therapy (NPWT) are frequently used for the preparation of skin excisions for a split thickness skin graft take. The trial compared the healing efficacy, safety and cost of patient care for these two treatments.

PATIENTS AND METHODS

This randomized, non-inferiority trial enrolled 113 patients who underwent skin excision (>30 cm²) and received ALGINATE or NPWT. The primary outcome was the time to obtain optimal granulation tissue for a split thickness skin graft take. Secondary outcomes were the occurrence of adverse events (AEs) and the impact of the patient care cost on the Social Security budget.

RESULTS

The mean time to optimal granulation was similar between ALGINATE and NPWT: approximately 20 days. No AE was reported with ALGINATE while 24 % of patients treated with NPWT presented an AE. Following hospitalization, 94 % of ALGINATE patients were cared for at home by a private nurse, while 90 % of NPWT patients were followed up in aftercare and rehabilitation facilities or home hospitalization. Therefore, the cost of treatment per patient for the French Social Security was 498 € with ALGINATE and 2104 € with NPWT.

CONCLUSION

This trial has demonstrated that ALGINATE has a similar healing efficacy to that of NPWT, and that it is markedly better with regard to patient safety and cost savings. ALGINATE should therefore be preferred to NPWT in this indication.

Sulfated Polysaccharides from Marine Algae as a Basis of Modern Biotechnologies for Creating Wound Dressings: Current Achievements and Future Prospects

Wound healing involves a complex cascade of cellular, molecular, and biochemical responses and signaling processes. It consists of successive interrelated phases, the duration of which depends on a multitude of factors. Wound treatment is a major healthcare issue that can be resolved by the development of effective and affordable wound dressings based on natural materials and biologically active substances. The proper use of modern wound dressings can significantly accelerate wound healing with minimum scar mark. Sulfated polysaccharides from seaweeds, with their unique structures and biological properties, as well as with a high potential to be used in various wound treatment methods, now undoubtedly play a major role in innovative biotechnologies of modern natural interactive dressings. These natural biopolymers are a novel and promising biologically active source for designing wound dressings based on alginates, fucoidans, carrageenans, and ulvans, which serve as active and effective therapeutic tools. The goal of this review is to summarize available information about the modern wound dressing technologies based on seaweed-derived polysaccharides, including those successfully implemented in commercial products, with a focus on promising and innovative designs. Future perspectives for the use of marine-derived biopolymers necessitate summarizing and analyzing results of numerous experiments and clinical trial data, developing a scientifically substantiated approach to wound treatment, and suggesting relevant practical recommendations.

Innovations in Infection Prevention and Treatment

Background: Patients with large, acute burn injuries are a major challenge for clinicians. The loss of skin barrier protection against micro-organisms combined with the induced immunosuppression after burn injury makes this population especially vulnerable to infection. For burn-injured patients who survive immediate management considerations and burn resuscitation after acute injury, sepsis remains the primary cause of death. The purpose of this article is to describe current strategies and innovations in burn sepsis prevention and management. Methods: This work reviews the current understanding of the systemic inflammatory response to burn injury and burn sepsis as well as current strategies in insolation and infection prevention, newer burn unit design strategies in the context of infection prevention, and novel therapies being considered in topical antimicrobial wound care management. Results: A review of burn sepsis is key to understanding current paradigms and innovation in burn management and prevention. Key management principles begin from the time of injury and persist throughout the patient's hospital course. This includes use of personal protective equipment, burn unit design considerations, and knowledge of critical care principles such as central venous catheter management strategies. Innovations on wound dressing types, forms, and use have been key to better controlling burn wound sepsis and improving wound healing. Products incorporating nanotechnology, novel anions, oxygen, and even light have been key to introducing previously unconsidered methods to fight or prevent infection. Conclusion: Understanding the pathophysiology and source identification of sepsis from burn wounds has been a key contributor in developing innovative prevention and therapeutic strategies in burn management. The emergence of drug-resistant pathogens and the difficulty of systemic antibiotic agents to reach poorly vascularized wounds have further reinforced the need to anticipate management strategies moving forward. A proactive, multidisciplinary approach is necessary to minimize the morbidity and mortality associated with infection control.

Marine Algae Polysaccharides as Basis for Wound Dressings, Drug Delivery, and Tissue Engineering: A Review

The present review considers the physicochemical and biological properties of polysaccharides (PS) from brown, red, and green algae (alginates, fucoidans, carrageenans, and ulvans) used in the latest technologies of regenerative medicine (tissue engineering, modulation of the drug delivery system, and the design of wound dressing materials). Information on various types of modern biodegradable and biocompatible PS-based wound dressings (membranes, foams, hydrogels, nanofibers, and sponges) is provided; the results of experimental and clinical trials of some dressing materials in the treatment of wounds of various origins are analyzed. Special attention is paid to the ability of PS to form hydrogels, as hydrogel dressings meet the basic requirements set out for a perfect wound dressing. The current trends in the development of new-generation PS-based materials for designing drug delivery systems and various tissue-engineering scaffolds, which makes it possible to create human-specific tissues and develop target-oriented and personalized regenerative medicine products, are also discussed.

ALGINATE versus NPWT in the Preparation of Surgical Excisions for an STSG: ATEC Trial

Supplemental Digital Content is available in the text.

A calcium alginate dressing (ALGINATE) and negative pressure wound therapy (NPWT) are frequently used to treat wounds which heal by secondary intention. This trial compared the healing efficacy and safety of these 2 treatments.

Polymeric carriers for enhanced delivery of probiotics

Probiotics are live microorganisms (usually bacteria), which are defined by their ability to confer health benefits to the host, if administered adequately. Probiotics are not only used as health supplements but have also been applied in various attempts to prevent and treat gastrointestinal (GI) and non-gastrointestinal diseases such as diarrhea, colon cancer, obesity, diabetes, and inflammation. One of the challenges in the use of probiotics is putative loss of viability by the time of administration. It can be due to procedures that the probiotic products go through during fabrication, storage, or administration. Biocompatible and biodegradable polymers with specific moieties or pH/enzyme sensitivity have shown great potential as carriers of the bacteria for 1) better viability, 2) longer storage times, 3) preservation from the aggressive environment in the stomach and 4) topographically targeted delivery of probiotics. In this review, we focus on polymeric carriers and the procedures applied for encapsulation of the probiotics into them. At the end, some novel methods for specific probiotic delivery, possibilities to improve the targeted delivery of probiotics and some challenges are discussed.

Exosome loaded alginate hydrogel promotes tissue regeneration in full-thickness skin wounds: An in vivo study

Wound healing is known as one of the most complicated biological processes for injured skin caused by surgical, trauma, burns, or diabetic diseases, which causes a nonfunctioning mass of fibrotic tissue. Recent reports have suggested that exosomes (EXOs) secreted by this type of stem cells may contribute to their paracrine effect. In this study, the EXOs were isolated from the supernatant of cultured adipose-derived stem cells (ADSCs) via ultracentrifugation and filtration. The EXO loaded in the alginate-based hydrogel was used as a bioactive scaffold to preserve the EXO in the wound site in the animal model. The physical and biochemical properties of EXO loaded Alg hydrogel were characterized and results proved that fabricated structure was biodegradable and biocompatible. This bioactive wound dressing technique has significantly improved wound closure, collagen synthesis, and vessel formation in the wound area. Results offer a new viewpoint and a cell-free therapeutic strategy, for wound healing through the application of the composite structure of EXO encapsulated in alginate hydrogel.

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings

As derivatives from marine natural biomaterials, alginate-based and chitosan-based biomaterials are commonly used in wound dressings. Calcium alginate fiber (CAF) dressings possess excellent absorption and unique gel forming performance, but the low bioactivity limits its application in wound healing. Carboxymethyl chitosan (CM-Chit) has excellent antibacterial activity, but the gel structure with weak mechanical properties restricts its application. In this study, minocycline (Mino)/CM-Chit solution was coated on the surface of plasma treated CAF needle-punched nonwovens, and then Mino loaded CM-Chit gel/CAF nonwovens composite dressings were fabricated by EDC/NHS (1-3-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide) crosslinking. The dressings had a porous composite structure, which allowed them to quickly absorb and store a large number of wound exudates. Skin-like tensile performance allowed the dressings to provide a better healing environment. Antibacterial assay against Escherichia coli and Staphylococcus aureus indicated that the addition of Mino significantly improved the antibacterial activity of the wound dressings. The tight structure of CM-Chit gel prevented the burst release of Mino so that the dressings had antibacterial activity in a certain period of release time. Cell culture assay showed that the dressings had excellent cell biocompatibility. As new functional dressings, the prepared composite dressings had excellent potential in the clinical healing of wounds.

Chemical Modification of Alginate for Controlled Oral Drug Delivery

Here, we report two methods that chemically modify alginate to achieve neutral-basic pH sensitivity of the resultant hydrogel. The first method involves direct amide bond formation between alginate and 4-(2-aminoethyl)benzoic acid. The second method that arose out of the desire to achieve better control of the degradation rate of the alginate hydrogel involves reductive amination of oxidized alginate. The products of both methods result in a hydrogel vehicle for targeted delivery of encapsulated payload under physiological conditions in the gastrointestinal tract. Two-dimensional diffusion-ordered spectroscopy and internal and coaxial external nuclear magnetic resonance standards were used to establish chemical bonding and percent incorporation of the modifying groups into the alginate polymer. The hydrogel made with alginate modified by each method was found to be completely stable under acidic pH conditions while disintegrating within minutes to hours in neutral-basic pH conditions. We found that, while alginate oxidation did not affect the β-d-mannuronate/α-l-guluronate ratio of alginate, the rate of disintegration of the hydrogel made with oxidized alginate was dependent upon the degree of oxidation.