Marine Polysaccharides for Wound Dressings Application: An Overview

Insights on Some Polysaccharide Gel Type Materials and Their Structural Peculiarities

Global resources have to be used in responsible ways to ensure the world's future need for advanced materials. Ecologically friendly functional materials based on biopolymers can be successfully obtained from renewable resources, and the most prominent example is cellulose, the well-known most abundant polysaccharide which is usually isolated from highly available biomass (wood and wooden waste, annual plants, cotton, etc.). Many other polysaccharides originating from various natural resources (plants, insects, algae, bacteria) proved to be valuable and versatile starting biopolymers for a wide array of materials with tunable properties, able to respond to different societal demands. Polysaccharides properties vary depending on various factors (origin, harvesting, storage and transportation, strategy of further modification), but they can be processed into materials with high added value, as in the case of gels. Modern approaches have been employed to prepare (e.g., the use of ionic liquids as "green solvents") and characterize (NMR and FTIR spectroscopy, X ray diffraction spectrometry, DSC, electronic and atomic force microscopy, optical rotation, circular dichroism, rheological investigations, computer modelling and optimization) polysaccharide gels. In the present paper, some of the most widely used polysaccharide gels will be briefly reviewed with emphasis on their structural peculiarities under various conditions.

Marine Biological Macromolecules and Chemically Modified Macromolecules; Potential Anticoagulants

Coagulation is a potential defense mechanism that involves activating a series of zymogens to convert soluble fibrinogen to insoluble fibrin clots to prevent bleeding and hemorrhagic complications. To prevent the extra formation and diffusion of clots, the counterbalance inhibitory mechanism is activated at levels of the coagulation pathway. Contrariwise, this system can evade normal control due to either inherited or acquired defects or aging which leads to unusual clots formation. The abnormal formations and deposition of excess fibrin trigger serious arterial and cardiovascular diseases. Although heparin and heparin-based anticoagulants are a widely prescribed class of anticoagulants, the clinical use of heparin has limitations due to the unpredictable anticoagulation, risk of bleeding, and other complications. Hence, significant interest has been established over the years to investigate alternative therapeutic anticoagulants from natural sources, especially from marine sources with good safety and potency due to their unique chemical structure and biological activity. This review summarizes the coagulation cascade and potential macromolecular anticoagulants derived from marine flora and fauna.

Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments

This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ΔEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7-6.1 × 10-11 mol m-1 s-1 Pa-1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (ε) (35.6-47.0%), low tensile strength at break (Ꞇ) (4.55-11.7 MPa) and low Young's modulus (εm) (10-93 MPa), whereas the other three were stiffer and more resistant with a higher Ꞇ (16.6-23.6 MPa), lower ε (2.80-5.58%), and higher εm (597-1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging.

Jellyfish Polysaccharides for Wound Healing Applications

Jellyfishes are considered a new potential resource in food, pharmaceutical and biomedical industries. In these latter cases, they are studied as source of active principles but are also exploited to produce marine collagen. In the present work, jellyfish skin polysaccharides (JSP) with glycosaminoglycan (GAG) features were extracted from Rhizostoma pulmo, a main blooming species of Mediterranean Sea, massively augmented by climate leaded “jellyfishication” of the sea. Two main fractions of R. pulmo JSP (RP-JSPs) were isolated and characterized, namely a neutral fraction (RP-JSP1) and a sulphate rich, negatively charged fraction (RP-JSP2). The two fractions have average molecular weights of 121 kDa and 590 kDa, respectively. Their sugar composition was evaluated through LC-MS analysis and the result confirmed the presence of typical GAG saccharides, such as glucose, galactose, glucosamine and galactosamine. Their use as promoters of wound healing was evaluated through in vitro scratch assay on murine fibroblast cell line (BALB/3T3 clone A31) and human keratinocytes (HaCaT). Both RP-JSPs demonstrated an effective confluency rate activity leading to 80% of scratch repair in two days, promoting both cell migration and proliferation. Additionally, RP-JSPs exerted a substantial protection from oxidative stress, resulting in improved viability of treated fibroblasts exposed to H₂O₂. The isolated GAG-like polysaccharides appear promising as functional component for biomedical skin treatments, as well as for future exploitation as pharmaceutical excipients.

Polysaccharide-based nanocomposites for biomedical applications: a critical review

Polysaccharides (PSA) have taken specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties are known as the main drawback of PSA, which highlights the need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use, they have not been reviewed. Herein, we critically reviewed the application of NPSA by categorizing them into generic and advanced application realms. First, the application of NPSA as drug and gene delivery systems, along with their role in the field as an antibacterial platform and hemostasis agent is discussed. Then, applications of NPSA for skin, bone, nerve, and cartilage tissue engineering are highlighted, followed by cell encapsulation and more critically cancer diagnosis and treatment potentials. In particular, three features of investigations are devoted to cancer therapy, i.e., radiotherapy, immunotherapy, and photothermal therapy, are comprehensively reviewed and discussed. Since this field is at an early stage of maturity, some other aspects such as bioimaging and biosensing are reviewed in order to give an idea of potential applications of NPSA for future developments, providing support for clinical applications. It is well-documented that using nanoparticles/nanomaterials above a critical concentration brings about concerns of toxicity; thus, their effect on cellular interactions would become critical. We compared nanoparticles used in the fabrication of NPSA in terms of toxicity mechanism to shed more light on future challenging aspects of NPSA development. Indeed, the neutralization mechanisms underlying the cytotoxicity of nanomaterials, which are expected to be induced by PSA introduction, should be taken into account for future investigations.

A Comprehensive Review of Cross-Linked Gels as Vehicles for Drug Delivery to Treat Central Nervous System Disorders

Gels are attractive candidates for drug delivery because they are easily producible while offering sustained and/or controlled drug release through various mechanisms by releasing the therapeutic agent at the site of action or absorption. Gels can be classified based on various characteristics including the nature of solvents used during preparation and the method of cross-linking. The development of novel gel systems for local or systemic drug delivery in a sustained, controlled, and targetable manner has been at the epitome of recent advances in drug delivery systems. Cross-linked gels can be modified by altering their polymer composition and content for pharmaceutical and biomedical applications. These modifications have resulted in the development of stimuli-responsive and functionalized dosage forms that offer many advantages for effective dosing of drugs for Central Nervous System (CNS) conditions. In this review, the literature concerning recent advances in cross-linked gels for drug delivery to the CNS are explored. Injectable and non-injectable formulations intended for the treatment of diseases of the CNS together with the impact of recent advances in cross-linked gels on studies involving CNS drug delivery are discussed.

An agar-polyvinyl alcohol hydrogel loaded with tannic acid with efficient hemostatic and antibacterial capacity for wound dressing

Rapid hemostasis, antibacterial effect and promotion of wound healing are the most important functions that wound dressings need to have. In this work, we designed and prepared a hydrogel with antibacterial effect, hemostatic ability and wound healing promotion using agar, polyvinyl alcohol (PVA) and tannic acid (TA). We performed a series of tests to characterize the structure and properties of AGAR@PVA-TA hydrogels. The results showed that the AGAR@PVA-TA hydrogels had good mechanical properties and excellent antibacterial ability as well as good hemocompatibility. The cytotoxicity results showed that the AGAR@PVA-TA hydrogels had good cytocompatibility. And the TA loaded hydrogels also presented some good performances in animal studies. In the liver hemostasis model, the AGAR@PVA-TA hydrogel showed good hemostatic ability. Also, the AGAR@PVA-TA hydrogel was able to promote wound healing in an S. aureus-infected rat wound model. More importantly, our research results demonstrated that compared to other polyphenols (such as proanthocyanidins), TA could better improve the mechanical properties, antibacterial ability and rapid hemostasis of hydrogels, which illustrated the uniqueness of TA. Therefore, the TA loaded hydrogel (AGAR@PVA-TA hydrogel) has the potential to be applied as a wound dressing.

The Future Packaging of the Food Industry: The Development and Characterization of Innovative Biobased Materials with Essential Oils Added

The need to replace conventional, usually single-use, packaging materials, so important for the future of resources and of the environment, has propelled research towards the development of packaging-based on biopolymers, fully biodegradable and even edible. The current study furthers the research on development of such films and tests the modification of the properties of the previously developed biopolymeric material, by adding 10, respectively 20% w/v essential oils of lemon, grapefruit, orange, cinnamon, clove, mint, ginger, eucalypt, and chamomile. Films with a thickness between 53 and 102 µm were obtained, with a roughness ranging between 147 and 366 nm. Most films had a water activity index significantly below what is required for microorganism growth, as low as 0.27, while all essential oils induced microbial growth reduction or 100% inhibition. Tested for the evaluation of physical, optical, microbiological or solubility properties, all the films with the addition of essential oil in the composition showed improved properties compared to the control sample.

Anionic exopolysaccharide from Cryptococcus laurentii 70766 as an alternative for alginate for biomedical hydrogels

Alginates are widely used polysaccharides for biomaterials engineering, which functional properties depend on guluronic and mannuronic acid as the building blocks. In this study, enzymatically crosslinked hydrogels based on sodium alginate (Na-Alg) and the exopolysaccharide (EPS) derived from Cryptococcus laurentii 70766 with glucuronic acid residues were synthesized and characterized as a new potential source of polysaccharide for biomaterials engineering. The EPS was extracted (1.05 ± 0.57 g/L) through ethanol precipitation. Then the EPS and Na-Alg were functionalized with tyramine hydrochloride to produce enzymatically crosslinked hydrogels in the presence of horseradish peroxidase (HRP) and H₂O₂. Major characteristics of the hydrogels such as gelling time, swelling ratio, rheology, cell viability, and biodegradability were studied. The swelling ratio and degradation profile of both hydrogels showed negative values, indicating an increased crosslinking degree and a lower water uptake percentage. The EPS hydrogel showed similar gelation kinetics compared to the Alg hydrogel. The EPS and its hydrogel were found cytocompatible. The results indicate the potential of EPS from C. laurentii 70766 for biomedical engineering due to its biocompatibility and degradability. Further studies are needed to confirm this EPS as an alternative for Alg in tissue engineering applications, particularly in the development of wound dressing products.

Active Potential of Bacterial Cellulose-Based Wound Dressing: Analysis of Its Potential for Dermal Lesion Treatment

The use of innate products for the fast and efficient promotion of healing process has been one of the biomedical sector's main bets for lesion treatment modernization process. The aim of this study was to develop and characterize bacterial cellulose-based (BC) wound dressings incorporated with green and red propolis extract (2 to 4%) and the active compounds p-coumaric acid and biochanin A (8 to 16 mg). The characterization of the nine developed samples (one control and eight active wound dressings) evidenced that the mechanics, physics, morphological, and barrier properties depended not only on the type of active principle incorporated onto the cellulosic matrix, but also on its concentration. Of note were the results found for transparency (28.59-110.62T₆₀₀ mm^-1), thickness (0.023-0.046 mm), swelling index (48.93-405.55%), water vapor permeability rate (7.86-38.11 g m² day^-1), elongation (99.13-262.39%), and antioxidant capacity (21.23-86.76 μg mL^-1). The wound dressing based on BC and red propolis was the only one that presented antimicrobial activity. The permeation and retention test revealed that the wound dressing containing propolis extract presented the most corneal stratum when compared with viable skin. Overall, the developed wound dressing showed potential to be used for treatment against different types of dermal lesions, according to its determined proprieties.

Multiple Roles of Chitosan in Mucosal Drug Delivery: An Updated Review

Chitosan (CS) is a linear polysaccharide obtained by the deacetylation of chitin, which, after cellulose, is the second biopolymer most abundant in nature, being the primary component of the exoskeleton of crustaceans and insects. Since joining the pharmaceutical field, in the early 1990s, CS attracted great interest, which has constantly increased over the years, due to its several beneficial and favorable features, including large availability, biocompatibility, biodegradability, non-toxicity, simplicity of chemical modifications, mucoadhesion and permeation enhancer power, joined to its capability of forming films, hydrogels and micro- and nanoparticles. Moreover, its cationic character, which renders it unique among biodegradable polymers, is responsible for the ability of CS to strongly interact with different types of molecules and for its intrinsic antimicrobial, anti-inflammatory and hemostatic activities. However, its pH-dependent solubility and susceptibility to ions presence may represent serious drawbacks and require suitable strategies to be overcome. Presently, CS and its derivatives are widely investigated for a great variety of pharmaceutical applications, particularly in drug delivery. Among the alternative routes to overcome the problems related to the classic oral drug administration, the mucosal route is becoming the favorite non-invasive delivery pathway. This review aims to provide an updated overview of the applications of CS and its derivatives in novel formulations intended for different methods of mucosal drug delivery.

Polysaccharide-Based Transdermal Drug Delivery

Materials derived from natural plants and animals have great potential for transdermal drug delivery. Polysaccharides are widely derived from marine, herbal, and microbial sources. Compared with synthetic polymers, polysaccharides have the advantages of non-toxicity and biodegradability, ease of modification, biocompatibility, targeting, and antibacterial properties. Currently, polysaccharide-based transdermal drug delivery vehicles, such as hydrogel, film, microneedle (MN), and tissue scaffolds are being developed. The addition of polysaccharides allows these vehicles to exhibit better-swelling properties, mechanical strength, tensile strength, etc. Due to the stratum corneum’s resistance, the transdermal drug delivery system cannot deliver drugs as efficiently as desired. The charge and hydration of polysaccharides allow them to react with the skin and promote drug penetration. In addition, polysaccharide-based nanotechnology enhances drug utilization efficiency. Various diseases are currently treated by polysaccharide-based transdermal drug delivery devices and exhibit promising futures. The most current knowledge on these excellent materials will be thoroughly discussed by reviewing polysaccharide-based transdermal drug delivery strategies.

How Effective are Nano-Based Dressings in Diabetic Wound Healing? A Comprehensive Review of Literature

Chronic wound caused by diabetes is an important cause of disability and seriously affects the quality of life of patients. Therefore, it is of great clinical significance to develop a wound dressing that can accelerate the healing of diabetic wounds. Nanoparticles have great advantages in promoting diabetic wound healing due to their antibacterial properties, low cytotoxicity, good biocompatibility and drug delivery ability. Adding nanoparticles to the dressing matrix and using nanoparticles to deliver drugs and cytokines to promote wound healing has proven to be effective. This review will focus on the effects of diabetes on wound healing, introduce the properties, preparation methods and action mechanism of nanoparticles in wound healing, and describe the effects and application status of various nanoparticle-loaded dressings in diabetes-related chronic wound healing.

Tissue Adhesive, Self-Healing, Biocompatible, Hemostasis, and Antibacterial Properties of Fungal-Derived Carboxymethyl Chitosan-Polydopamine Hydrogels

In this work, fungal mushroom-derived carboxymethyl chitosan-polydopamine hydrogels (FCMCS-PDA) with multifunctionality (tissue adhesive, hemostasis, self-healing, and antibacterial properties) were developed for wound dressing applications. The hydrogel is obtained through dynamic Schiff base cross-linking and hydrogen bonds between FCMCS-PDA and covalently cross-linked polyacrylamide (PAM) networks. The FCMCS-PDA-PAM hydrogels have a good swelling ratio, biodegradable properties, excellent mechanical properties, and a highly interconnected porous structure with PDA microfibrils. Interestingly, the PDA microfibrils were formed along with FCMCS fibers in the hydrogel networks, which has a high impact on the biological performance of hydrogels. The maximum adhesion strength of the hydrogel to porcine skin was achieved at about 29.6 ± 2.9 kPa. The hydrogel had good self-healing and recoverable properties. The PDA-containing hydrogels show good antibacterial properties on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. Moreover, the adhesive hydrogels depicted good viability and attachment of skin fibroblasts and keratinocyte cells. Importantly, FCMCS and PDA combined resulted in fast blood coagulation within 60 s. Hence, the adhesive hydrogel with multifunctionality has excellent potential as a wound dressing material for infected wounds.

Recent progress of collagen, chitosan, alginate and other hydrogels in skin repair and wound dressing applications

Human understanding of skin is constantly ongoing. Great progress has been made in skin repair, wound dressing regeneration biomaterials research in recent years. This review introduced the clinical research and guiding principles of skin repair, wound dressing biomaterials at home and abroad, introduced the classification of various skin repair and wound dressing, listed the composition and performance of different dressing biomaterials, including traditional, natural, synthetic, tissue-engineered dressing materials were extensively reviewed. The biological molecular structures and biological function characteristics of different dressing biomaterials are comprehensively reviewed. Collagen, chitosan, alginate hydrogels et al. as the most popular biological macromolecules in skin repair and wound dressing applications were reviewed. The future development direction is also prospected. This paper reviews the research progress of advanced functional skin repair and wound dressing, which provides a reference for the modifications and applications of wound dressings.

Wound Dressing: Combination of Acacia Gum/PVP/Cyclic Dextrin in Bioadhesive Patches Loaded with Grape Seed Extract

The success of wound treatment is conditioned by the combination of both suitable active ingredients and formulation. Grape seed extract (GSE), a waste by-product obtained by grape processing, is a natural source rich in many phenolic compounds responsible for antioxidant, anti-inflammatory, and antimicrobial activities and for this reason useful to be used in a wound care product. Bioadhesive polymeric patches have been realized by combining acacia gum (AG) and polyvinylpyrrolidone (PVP). Prototypes were prepared by considering different AG/PVP ratios and the most suitable in terms of mechanical and bioadhesion properties resulted in the 9.5/1.0 ratio. This patch was loaded with GSE combined with cyclic dextrin (CD) to obtain the molecular dispersion of the active ingredient in the dried formulation. The loaded patch resulted mechanically resistant and able to release GSE by a sustained mechanism reaching concentrations able to stimulate keratinocytes’ growth, to exert both antibacterial and antioxidant activities.

The performance of gelling fibre wound dressings under clinically relevant robotic laboratory tests

The effectiveness of wound dressing performance in exudate management is commonly gauged in simple, non‐realistic laboratory setups, typically, where dressing specimens are submersed in vessels containing aqueous solutions, rather than by means of clinically relevant test configurations. Specifically, two key fluid–structure interaction concepts: sorptivity—the ability of wound dressings to transfer exudate, including viscous fluids, away from the wound bed by capillary action and durability—the capacity of dressings to maintain their structural integrity over time and particularly, at removal events, have not been properly addressed in existing test protocols. The present article reviews our recent published research concerning the development of clinically relevant testing methods for wound dressings, focussing on the clinical relevance of the tests as well as on the standardisation and automation of laboratory measurements of dressing performance. A second objective of this work was to compile the experimental results characterising the performance of gelling fibre dressings, which were acquired using advanced testing methods, to demonstrate differences across products that apparently belong to the same “gelling fibre” family but differ remarkably in materials, structure and composition and, thereby, in performance.

Characterization and Biocompatibility Properties In Vitro of Gel Beads Based on the Pectin and κ-Carrageenan

This study aimed to investigate the influence of kappa (κ)-carrageenan on the initial stages of the foreign body response against pectin gel. Pectin-carrageenan (P-Car) gel beads were prepared from the apple pectin and κ-carrageenan using gelling with calcium ions. The inclusion of 0.5% κ-carrageenan (Car0.5) in the 1.5 (P1.5) and 2% pectin (P2) gel formulations decreased the gel strength by 2.5 times. Car0.5 was found to increase the swelling of P2 gel beads in the cell culture medium. P2 gel beads adsorbed 30–42 mg/g of bovine serum albumin (BSA) depending on pH. P2-Car0.2, P2-Car0.5, and P1.5-Car0.5 beads reduced BSA adsorption by 3.1, 5.2, and 4.0 times compared to P2 beads, respectively, at pH 7. The P1.5-Car0.5 beads activated complement and induced the haemolysis less than gel beads of pure pectin. Moreover, P1.5-Car0.5 gel beads allowed less adhesion of mouse peritoneal macrophages, TNF-α production, and NF-κB activation than the pure pectin gel beads. There were no differences in TLR4 and ICAM-1 levels in macrophages treated with P and P-Car gel beads. P2-Car0.5 hydrogel demonstrated lower adhesion to serous membrane than P2 hydrogel. Thus, the data obtained indicate that the inclusion of κ-carrageenan in the apple pectin gel improves its biocompatibility.

Nutritional Therapy in Persons Suffering from Psoriasis

Psoriasis is a chronic inflammatory skin disease. Immunological, genetic, and environmental factors, including diet, play a part in the pathogenesis of psoriasis. Metabolic syndrome or its components are frequent co-morbidities in persons with psoriasis. A change of eating habits can improve the quality of life of patients by relieving skin lesions and by reducing the risk of other diseases. A low-energy diet is recommended for patients with excess body weight. Persons suffering from psoriasis should limit the intake of saturated fatty acids and replace them with polyunsaturated fatty acids from the omega-3 family, which have an anti-inflammatory effect. In diet therapy for persons with psoriasis, the introduction of antioxidants such as vitamin A, vitamin C, vitamin E, carotenoids, flavonoids, and selenium is extremely important. Vitamin D supplementation is also recommended. Some authors suggest that alternative diets have a positive effect on the course of psoriasis. These diets include: a gluten-free diet, a vegetarian diet, and a Mediterranean diet. Diet therapy for patients with psoriasis should also be tailored to pharmacological treatment. For instance, folic acid supplementation is introduced in persons taking methotrexate. The purpose of this paper is to discuss in detail the nutritional recommendations for persons with psoriasis.

Chitosan Membrane Containing Copaiba Oil (Copaifera spp.) for Skin Wound Treatment

The interaction of copaiba oil in the polymer matrix of chitosan can produce a favorable synergistic effect and potentiate properties. Indeed, the bioactive principles present in copaiba oil have anti-inflammatory and healing action. In the present work, chitosan membranes containing different contents of copaiba oil copaíba (0.1, 0.5, 1.0 and 5.0% (v/v)) were for the first time investigated. The membranes were developed by the casting method and analyzed for their morphology, degree of intumescence, moisture content, contact angle, Scanning Electron Microscope, and X-ray diffractometry. These chitosan/copaiba oil porous membranes disclosed fluid absorption capacity, hydrophilic surface, and moisture. In addition, the results showed that chitosan membranes with the addition of 1.0% (v/v) of copaiba oil presented oil drops with larger diameters, around 123.78 μm. The highest fluid absorption indexes were observed in chitosan membranes containing 0.1 and 0.5% (v/v) of copaiba oil. In addition, the copaiba oil modified the crystalline structure of chitosan. Such characteristics are expected to favor wound treatment. However, biological studies are necessary for the safe use of chitosan/copaiba oil membrane as a biomaterial.

Recent Advances in Functional Polymer Materials for Energy, Water, and Biomedical Applications: A Review

Academic research regarding polymeric materials has been of great interest. Likewise, polymer industries are considered as the most familiar petrochemical industries. Despite the valuable and continuous advancements in various polymeric material technologies over the last century, many varieties and advances related to the field of polymer science and engineering still promise a great potential for exciting new applications. Research, development, and industrial support have been the key factors behind the great progress in the field of polymer applications. This work provides insight into the recent energy applications of polymers, including energy storage and production. The study of polymeric materials in the field of enhanced oil recovery and water treatment technologies will be presented and evaluated. In addition, in this review, we wish to emphasize the great importance of various functional polymers as effective adsorbents of organic pollutants from industrial wastewater. Furthermore, recent advances in biomedical applications are reviewed and discussed.

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

Chitosan is one of the most studied natural origin polymers for biomedical applications. This review focuses on the potential of chitosan in localized antimicrobial therapy to address the challenges of current rising antimicrobial resistance. Due to its mucoadhesiveness, chitosan offers the opportunity to prolong the formulation residence time at mucosal sites; its wound healing properties open possibilities to utilize chitosan as wound dressings with multitargeted activities and more. We provide an unbiased overview of the state-of-the-art chitosan-based delivery systems categorized by the administration site, addressing the site-related challenges and evaluating the representative formulations. Specifically, we offer an in-depth analysis of the current challenges of the chitosan-based novel delivery systems for skin and vaginal infections, including its formulations optimizations and limitations. A brief overview of chitosan's potential in treating ocular, buccal and dental, and nasal infections is included. We close the review with remarks on toxicity issues and remaining challenges and perspectives.

Chitosan-Platelet-Rich Plasma Implants Improve Rotator Cuff Repair in a Large Animal Model: Pivotal Study

The purpose of this study was to assess the safety and efficacy of chitosan-platelet-rich plasma (PRP) hybrid implants used as an adjunct to surgical rotator cuff repair in a pivotal Good Laboratory Practice (GLP)-compliant study. The infraspinatus tendon was transected in 48 skeletally mature ewes and repaired with a transosseous-equivalent (TOE) technique. In the two treatment groups, a chitosan-PRP solution was injected at the footprint between the tendon and the bone and on top of the repaired site (2 mL or 3 mL doses, n = 12 per group). To further assess chitosan safety, a chitosan-water solution was injected at the same sites (3 mL, n = 12). Outcome measures included Magnetic Resonance Imaging (MRI) assessment and clinical pathology at 3 months and 6 months and histopathology at 6 months. The tendon gap was decreased at 3 months on MRI images and certain histopathological features were improved at 6 months by chitosan-PRP treatment compared to controls. The group treated with chitosan-water was not different from controls. Chitosan-PRP treatment induced no negative effects in the sheep, which suggests high safety. This study provides further evidence on the safety and efficacy of chitosan-PRP for rotator cuff repair augmentation, which could eventually be used in a clinical setting.