Physically cross-linked chitosan-based hydrogels for tissue engineering applications: A state-of-the-art review

Chitosan as a tool for tissue engineering and rehabilitation: Recent developments and future perspectives - A review

Chitosan has established itself as a multifunctional and auspicious biomaterial within the domain of tissue engineering, presenting a decade of uninterrupted advancements and novel implementations. This article provides a comprehensive overview of the most recent developments in chitosan-based tissue engineering, focusing on significant progress made in the last ten years. An exploration is conducted of the various techniques utilized in the modification of chitosan and the production of scaffolds, with an analysis of their effects on cellular reactions and tissue regeneration. The investigation focuses on the integration of chitosan with other biomaterials and the addition of bioactive agents to improve their functionalities. Upon careful analysis of the in vitro and in vivo research, it becomes evident that chitosan effectively stimulates cell adhesion, proliferation, and differentiation. Furthermore, we offer valuable perspectives on the dynamic realm of chitosan-based approaches tailored to distinct tissue categories, including nerve, bone, cartilage, and skin. The review concludes with a discussion of prospective developments, with particular attention given to possible directions for additional study, translational implementations, and the utilization of chitosan to tackle existing obstacles in the field of tissue engineering. This extensive examination provides a significant amalgamation of the advancements achieved over the previous decade and directs scholars towards uncharted territories in chitosan-based tissue engineering.

Modelling methacrylated chitosan hydrogel properties through an experimental design approach: from composition to material properties

Hydrogels of biopolymers are gradually substituting synthetic hydrogels in tissue engineering applications due to their properties. However, biopolymeric hydrogels are difficult to standardize because of the intrinsic variability of the material and the reversibility of physical crosslinking processes. In this work, we synthesized a photocrosslinkable derivative of chitosan (Cs), namely methacrylated chitosan (CsMA), in which the added methacrylic groups allow the formation of hydrogels through radical polymerization triggered by UV exposure. We then performed a systematic study to link the physical properties of the materials to its preparation parameters to standardize its preparation according to specific applications. We studied the properties of CsMA solutions and the derived hydrogels using a statistical method, namely, response surface method, which allowed us to build empirical models describing material properties in terms of several selected processing factors. In particular, we studied the viscosity of CsMA solutions as a function of CsMA concentration, temperature, and shear rate, while hydrogel compression modulus, morphology, degradation and solubilization were investigated as a function of CsMA concentration, photoinitiator concentration and UV exposure. CsMA solutions resulted in shear thinning and were thus suitable for extrusion-based 3D printing. The CsMA hydrogel was found to be highly tunable, with a stiffness in the 12-64 kPa range, and was stable over a long timeframe (up to 60 days). Finally, the possibility to engineer hydrogel stiffness through an empirical model allowed us to hypothesize a number of possible applications based on the mechanical properties of several biological tissues reported in the literature.

Stretchable hydrogels of chitosan/hyaluronic acid induced by polyelectrolyte complexation around neutral pH

In this work, we propose the formation of stretchable hydrogels at neutral pH from the physical crosslinking of chitosan (CS) and hyaluronic acid (HA) by polyelectrolyte complexation. A mixture of CS (Mw ≈ 600 kg/mol, degree of acetylation ≈ 50 %) solution and HA (Mw ≈ 77 kg/mol) solution was prepared with an excess of salts screening the electrostatic interactions CS/HA. In a controlled manner, the polyelectrolyte complexation was induced through the progressive dialysis of the salted polymer mixture against a sodium acetate solution (AcONa, 0.01 M) for 7 days. Depending on [HA], various materials were obtained: viscous solutions at [HA] = 0.75 % (w/v); hydrogels at [HA] = 1.50-2.24 % (w/v) with Young modulus of 14 kPa and stretchable to 200 %. The small angle X-ray scattering characterization of the hydrogels revealed a multiscale organization related to the conformation of the polymers induced by the physical interactions. The dialysis process with AcONa was optimized by adding a dialysis step against a zinc acetate solution containing Zn2+. The combination of polyelectrolyte complexation between CS/HA and metal complexation between Zn2+ and the polymers led to an enhancement of the hydrogel stretchability up to 400 %.

Minimally invasive soft tissue repair using shrunken scaffolds

The minimally invasive injection of tissue engineering scaffolds is of interest as it requires a smaller incision and quickens recovery. However, the engineering of scaffolds capable of injection remains a challenge. Here, we report on a shrunken scaffold inspired by the shrinking of puffed food in a humid environment. A scaffold is freeze-dried to remove water then placed in a humid atmosphere. The humidity causes the dry scaffold to shrink by up to 90%. In addition, the humidity treatment reduces the scaffolds modulus minimizing the foreign body response after implantation. The scaffolds can rapidly swell into their original size and shape after application. A tool for the delivery of the minimally invasive scaffolds is developed and we demonstrate the potential for minimally invasive delivery using this shrinking technique.

Rational Design of a Multifunctional Hydrogel Trap for Water and Fertilizer Capture: A Review

Water scarcity and land infertility pose significant challenges to agricultural development, particularly in arid and semiarid regions. Improving soil-water-retention capacity and fertilizer utilization efficiency through the application of soil additives has become a pivotal approach in agricultural practices. Hydrogels exhibit exceptional water absorption and fertilizer retention capabilities, making them extensively utilized in the fields of agriculture, forestry, and desert control. Currently, most reviews primarily focus on the raw materials, classification, synthesis methods, and application prospects of hydrogels, with limited attention given to strategies for enhancing water-retention performance, mechanisms underlying fertilizer absorption, and environmental risks. This review covers the commonly used cross-linking methods in hydrogel synthesis and the structure-activity relationship between hydrogels and water as well as fertilizer. Additionally, a thorough analysis of the ecological benefits and risks associated with hydrogels is presented. Finally, future prospects and challenges are delineated from the perspectives of material design and engineering applications.

Functional Bio-Based Polymeric Hydrogels for Wastewater Treatment: From Remediation to Sensing Applications

In recent years, many researchers have focused on designing hydrogels with specific functional groups that exhibit high affinity for various contaminants, such as heavy metals, organic pollutants, pathogens, or nutrients, or environmental parameters. Novel approaches, including cross-linking strategies and the use of nanomaterials, have been employed to enhance the structural integrity and performance of the desired hydrogels. The evolution of these hydrogels is further highlighted, with an emphasis on fine-tuning features, including water absorption capacity, environmental pollutant/factor sensing and selectivity, and recyclability. Furthermore, this review investigates the emerging topic of stimuli-responsive smart hydrogels, underscoring their potential in both sorption and detection of water pollutants. By critically assessing a wide range of studies, this review not only synthesizes existing knowledge, but also identifies advantages and limitations, and describes future research directions in the field of chemically engineered hydrogels for water purification and monitoring with a low environmental impact as an important resource for chemists and multidisciplinary researchers, leading to improvements in sustainable water management technology.

Coordinating Macrophage Targeting and Antioxidation by Injectable Nanocomposite Hydrogel for Enhanced Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA), an immune-mediated inflammatory disease, is characterized by a large number of infiltrated immune cells and abnormally elevated reactive oxygen species (ROS) in the joint. Various proinflammatory factors secreted by macrophages and the elevated ROS by inflammatory cells are deeply intertwined and together contribute to joint damage. Targeted and sustained anti-inflammation and antioxidation strategies are needed for RA treatment. To alleviate the oxidative stress and target the source of inflammatory cytokines, we developed a thermosensitive injectable hydrogel, Dex-DSLip/Cro@Gel, to coordinate the targeted anti-inflammatory and antioxidation effects. Within the injectable gel, dexamethasone (Dex)-loaded liposomes (Dex-DSLip), modified with dextran sulfate (DS), target macrophages via interaction with scavenger receptor A (SR-A). Simultaneously, crocin I (Cro) is loaded in the gel with a high loading capacity. The porous structure of Dex-DSLip/Cro@Gel successfully prolongs the retention time of both drugs and sustains the release of Dex and Cro. After intra-articular injection of Dex-DSLip/Cro@Gel in RA rats, the expression of inflammatory factors in the ankle joints was significantly reduced. Joint erythema and bone erosion were markedly alleviated. Through the synergistic effects of Dex and Cro, Dex-DSLip/Cro@Gel demonstrates targeted anti-inflammatory and antioxidation effects as well as mitigated bone erosion and long-term therapeutic effects for RA. This thermosensitive injectable nanocomposite hydrogel synergizes anti-inflammatory and antioxidation effects and targets the microenvironment in the joint, offering a new approach for RA treatment.

Scaffold-Mediated Drug Delivery for Enhanced Wound Healing: A Review

Wound healing is a complex physiological process involving coordinated cellular and molecular events aimed at restoring tissue integrity. Acute wounds typically progress through the sequential phases of hemostasis, inflammation, proliferation, and remodeling, while chronic wounds, such as venous leg ulcers and diabetic foot ulcers, often exhibit prolonged inflammation and impaired healing. Traditional wound dressings, while widely used, have limitations such poor moisture retention and biocompatibility. To address these challenges and improve patient outcomes, scaffold-mediated delivery systems have emerged as innovative approaches. They offer advantages in creating a conducive environment for wound healing by facilitating controlled and localized drug delivery. The manuscript explores scaffold-mediated delivery systems for wound healing applications, detailing the use of natural and synthetic polymers in scaffold fabrication. Additionally, various fabrication techniques are discussed for their potential in creating scaffolds with controlled drug release kinetics. Through a synthesis of experimental findings and current literature, this manuscript elucidates the promising potential of scaffold-mediated drug delivery in improving therapeutic outcomes and advancing wound care practices.

Current trend on preparation, characterization and biomedical applications of natural polysaccharide-based nanomaterial reinforcement hydrogels: A review

The tunable properties of hydrogels have led to their widespread use in various biomedical applications such as wound treatment, drug delivery, contact lenses, tissue engineering and 3D bioprinting. Among these applications, natural polysaccharide-based hydrogels, which are fabricated from materials like agarose, alginate, chitosan, hyaluronic acid, cellulose, pectin and chondroitin sulfate, stand out as preferred choices due to their biocompatibility and advantageous fabrication characteristics. Despite the inherent biocompatibility, polysaccharide-based hydrogels on their own tend to be weak in physiochemical and mechanical properties. Therefore, further reinforcement in the hydrogel is necessary to enhance its suitability for specific applications, ensuring optimal performance in diverse settings. Integrating nanomaterials into hydrogels has proven effective in improving the overall network and performance of the hydrogel. This approach also addresses the limitations associated with pure hydrogels. Next, an overview of recent trends in the fabrication and applications of hydrogels was presented. The characterization of hydrogels was further discussed, focusing specifically on the reinforcement achieved with various hydrogel materials used so far. Finally, a few challenges associated with hydrogels by using polysaccharide-based nanomaterial were also presented.

Chitosan-nanoclay embolic material for catheter-directed arterial embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology. It is used for the deliberate occlusion of blood vessels for the treatment of disease or injured vasculature, including vascular malformation and malignant/benign tumors. Here, we introduce a gel embolic agent comprising chitosan nanofibers and nanoclay with excellent catheter injectability and tunable mechanical properties for embolization. The properties of the gel were optimized by varying the ratio between each individual component and also adjusting the total solid content. The rheological studies confirm the shear thinning property and gel nature of the developed gel as well as their recoverability. Injection force was measured to record the force required to pass the embolic gel through a clinically relevant catheter, evaluating for practicality of hand-injection. Theoretical predicted injection force was calculated to reduce the development time and to enhance the physician's experience. The stability of occlusion was also tested in vitro by monitoring the pressure required to displace the gel. The engineered gels exhibited sterility, hemocompatibility and cell biocompatibility, highlighting their potential for transcatheter embolization.

Biofilm hydrogel derived from physical crosslinking (self-assembly) of xanthan gum and chitosan for removing Cd2+, Ni2+, and Cu2+ from aqueous solution

This study aimed to fabricate a series of biodegradable hydrogel films by gelating/physically crosslinking a blend of xanthan gum (XG) and chitosan (CS) in various combinations using a facile, green, and low cost solution casting technique. The adsorption of Cd2+, Cu2+ and Ni2+ by the XG/CS biofilm in aqueous solution was studied in batch experiments to determine how the pH of the solution, contact time, dosage of adsorbent, initial metal ion concentration and ionic strength affect its adsorption. A highly pH-dependent adsorption process was observed for three metal ions. A maximum amount of Cd2+, Ni2+, and Cu2+ ions was adsorbable with 50 mg of the adsorbent at pH 6.0 for an initial metal concentration of 50 mg.L-1. An empirical pseudo-second-order model seems to fit the kinetic experimental data reasonably well. It was found that the Langmuir model correlated better with equilibrium isotherm when compared with the Freundlich model. For Cd2+, Ni2+, and Cu2+ ions at 25 °C, the maximum monolayer adsorption capacity was 152.33, 144.79, and 139.71 mg.g-1, respectively. Furthermore, the biofilm was capable of regenerating, allowing metal ions to adsorb and desorb for five consecutive cycles. Therefore, the developed biodegradable film offers the potential for remediation of specified metal ions.

Ammonia-responsive chitosan/polymethacrylamide double network hydrogels with high-stretchability, fatigue resistance and anti-freezing for real-time chicken breast spoilage monitoring

Hydrogels are a promising option for detecting food spoilage in humid conditions, but current indicators are prone to mechanical flaws, posing a concern for packaging systems that require strong mechanical properties. Herein, a double network hydrogel was prepared by polymerizing methacrylamide in a chitosan system with aluminum chloride and glycerol. The resulting hydrogel demonstrated high stretchability (strain >1500 %), notch insensitivity, excellent fatigue resistance, and exceptional anti-freezing capabilities even at -21 °C. When incorporating bromothymol blue (BB) or methyl red (MR), or mixtures of these dyes into the hydrogels as indicators, they exhibited sensitive colorimetric responses to pH and NH3 levels at different temperatures. Hydrogels immobilizing BB to MR ratios of 1:1 and 1:2 displayed clearer and more sensitive color responses when packed into chicken breast, with a sensitivity level of 1.5 ppm of total volatile basic nitrogen (TVB-N). This color response correlated positively with the accumulation of TVB-N on the packaging during storage at both 25 °C and 4 °C, providing sensitive indications of chicken breast deterioration. Overall, the developed hydrogels and indicators demonstrate enhanced performance characteristics, including excellent mechanical strength and highly NH3-sensitive color responses, making significant contributions to the food spoilage detection and intelligent packaging systems field.

The utilization of chitosan/Bletilla striata hydrogels to elevate anti-adhesion, anti-inflammatory and pro-angiogenesis properties of polypropylene mesh in abdominal wall repair

Polypropylene (PP) mesh is commonly used in abdominal wall repair due to its ability to reduce the risk of organ damage, infections and other complications. However, the PP mesh often leads to adhesion formation and does not promote functional tissue repair. In this study, we synthesized one kind of aldehyde Bletilla striata polysaccharide (BSPA) modified chitosan (CS) hydrogel based on Schiff base reaction. The hydrogel exhibited a porous network structure, a highly hydrophilic surface and good biocompatibility. We wrapped the PP mesh inside the hydrogel and evaluated the performance of the resulting composites in a bilateral 1 × 1.5 cm abdominal wall defect model in rats. The results of gross observation, histological staining and immunohistochemical staining demonstrated the positive impact of the CS hydrogel on anti-adhesion and wound healing effects. Notably, the addition of BSPA to the CS hydrogel further improved the performance of the composites in vivo, promoting wound healing by enhancing collagen deposition and capillary rearrangement. This study suggested that the BSPA-modified CS hydrogel significantly promoted the anti-adhesion, anti-inflammatory and pro-angiogenesis properties of PP meshes during the healing process. Overall, this work offers a novel approach to the design of abdominal wall repair patches.

Schiff Base-Based Hydrogel Embedded with In Situ Generated Silver Nanoparticles Capped by a Hyaluronic Acid-Diethylenetriamine Derivative for Wound Healing Application

In this study, hydrogels were produced using a Schiff base reaction between two hyaluronic acid derivatives: one containing aldehyde groups (HA-Ald) and the other holding a diethylenetriamine with terminal amino groups (HA-DETA). The DETA portion promotes the in situ growth, complexation, and stabilization of silver nanoparticles (AgNPs), eliminating the need for external reducing agents. The reaction between HA-DETA and HA-Ald leads to the formation of imine bonds, which results in dynamically pH-responsive cross-linking. While the DETA capping ability helped in embedding the AgNPs, the on/off pH environmental responsivity of the hydrogel allows for a controlled and on-demand release of the drug, mainly when bacterial infections cause pH variation of the wound bed. The injectable hydrogels resulted in being highly compatible in contact with blood red cells, fibroblasts, and keratinocytes and capable of having a proliferative effect on an in vitro wound scratch model. The pH-responsive hydrogels showed proper antibacterial activity againstPseudomonas aeruginosaandStaphylococcus aureus, common bacterial strains presented in wound infections. Finally, in vivo wound model studies demonstrated an overall speeding up in the wound healing rate and advanced wound conditions in the experimental group treated with the hydrogels compared to control samples.

Chitosan hydrogels enriched with bioactive phloroglucinol for controlled drug diffusion and potential wound healing

We report a facile strategy to prepare chitosan (CS) hydrogels that eliminates the need for chemical crosslinking for advanced biomedical therapies. This approach gives controlled properties to the hydrogels by incorporating a natural bioactive phenolic compound, phloroglucinol (PG), into their microstructure. The adsorption of PG onto CS chains enhanced the hydrogels' antioxidant activity by up to 25 % and resulted in a denser, more entangled structure, reducing the pore size by 59 μm while maintaining porosity above 94 %. This allowed us to finely adjust pore size and swelling capacity. These structural properties make these hydrogels well-suited for wound healing dressings, promoting fibroblast proliferation and exhibiting excellent hemocompatibility. Furthermore, to ensure the versatility of these hydrogels, herein, we demonstrate their potential as drug delivery systems, particularly for dermal infections. The drug release can be controlled by a combination of drug diffusion through the swollen hydrogel and relaxation of the CS chains. In summary, our hydrogels leverage the synergistic effects of CS's antibacterial and antifungal properties with PG's antimicrobial and anti-inflammatory attributes, positioning them as promising candidates for biomedical and pharmaceutical applications, more specifically in advanced wound healing therapies with local drug delivery.

Injectable Hydrogels for Nervous Tissue Repair-A Brief Review

The repair of nervous tissue is a critical research field in tissue engineering because of the degenerative process in the injured nervous system. In this review, we summarize the progress of injectable hydrogels using in vitro and in vivo studies for the regeneration and repair of nervous tissue. Traditional treatments have not been favorable for patients, as they are invasive and inefficient; therefore, injectable hydrogels are promising for the treatment of damaged tissue. This review will contribute to a better understanding of injectable hydrogels as potential scaffolds and drug delivery system for neural tissue engineering applications.

Pharmaceutical applications of chitosan in skin regeneration: A review

Skin regeneration is the process that restores damaged tissues. When the body experiences trauma or surgical incisions, the skin and tissues on the wound surface become damaged. The body repairs this damage through complex physiological processes to restore the original structural and functional states of the affected tissues. Chitosan, a degradable natural bioactive polysaccharide, has attracted widespread attention partly owing to its excellent biocompatibility and antimicrobial properties; additionally, a modified form of this compound has been shown to promote skin regeneration. This review evaluates the recent research progress in the application of chitosan to promote skin regeneration. First, we discuss the basic principles of the extraction and preparation processes of chitosan from its source. Subsequently, we describe the functional properties of chitosan and the optimization of these properties through modification. We then focus on the existing chitosan-based biomaterials developed for clinical applications and their corresponding effects on skin regeneration, particularly in cases of diabetic and burn wounds. Finally, we explore the challenges and prospects associated with the use of chitosan in skin regeneration. Overall, this review provides a reference for related research and contributes to the further development of chitosan-based products in cutaneous skin regeneration.

Organic-inorganic composite hydrogels: compositions, properties, and applications in regenerative medicine

Hydrogels, formed from crosslinked hydrophilic macromolecules, provide a three-dimensional microenvironment that mimics the extracellular matrix. They served as scaffold materials in regenerative medicine with an ever-growing demand. However, hydrogels composed of only organic components may not fully meet the performance and functionalization requirements for various tissue defects. Composite hydrogels, containing inorganic components, have attracted tremendous attention due to their unique compositions and properties. Rigid inorganic particles, rods, fibers, etc., can form organic-inorganic composite hydrogels through physical interaction and chemical bonding with polymer chains, which can not only adjust strength and modulus, but also act as carriers of bioactive components, enhancing the properties and biological functions of the composite hydrogels. Notably, incorporating environmental or stimulus-responsive inorganic particles imparts smartness to hydrogels, hence providing a flexible diagnostic platform for in vitro cell culture and in vivo tissue regeneration. In this review, we discuss and compare a set of materials currently used for developing organic-inorganic composite hydrogels, including the modification strategies for organic and inorganic components and their unique contributions to regenerative medicine. Specific emphasis is placed on the interactions between the organic or inorganic components and the biological functions introduced by the inorganic components. The advantages of these composite hydrogels indicate their potential to offer adaptable and intelligent therapeutic solutions for diverse tissue repair demands within the realm of regenerative medicine.

Multifunctional Wound Curation Dressing Material FemuFrost─An Antioxidant-Loaded Nanoemulsion Frosted Patch of Poly(vinyl alcohol) and Hyaluronic Acid

The wound curation dressing material should own explicit elements to aggrandize wound cessation. The cryogel of poly(vinyl alcohol) (PVA) and hyaluronic acid (HA) is deemed to promote the angiogenesis, production of extracellular matrix components, granulation, and epithelialization. The research aims to tailor and evaluate the composite PVA/HA cryogel ingrained ferulic acid-loaded nanoemulsion patch labeled as PH-FemuFrost to improve the therapeutic properties and mechanical strength of the patches. The PH-FemuFrost exhibited a water uptake capacity of 268 ± 15.07%, porosity of 70.52 ± 7.4%, and 48.62 ± 2.2% in vitro degradation. The texture analysis revealed the improved mechanical properties of PH-FemuFrost in terms of burst strength and stiffness. The PH-FemuFrost exhibited in vitro antioxidant and antimicrobial activity against Staphylococcus aureus and Candida albicans species. The wound healing efficiency of PH-FemuFrost patches was significantly increased than blank PVA-HA patches. The groups treated with PH-FemuFrost exhibited a dense network of collagen type 1 in comparison to negative and PVA-HA groups. The normal skin and healed skin exhibited parallel arrangement of type I collagen fibers toward the skin. The levels of inflammatory mediators such as IL-6 (p value < 0.0001), IL-22 (p value 0.0098), and TNF-α levels (p value < 0.0001) of PH-FemuFrost is significantly reduced compared to the negative group.

Photochemical stability of chitosan films doped with cannabis oil

The effect of UV radiation from three different sources on chitosan (CS) films containing the addition of 10% by weight of cannabis oil was investigated. Cannabis oil (CBD) alone exposed to UV is unstable, but its photostability significantly increases in the chitosan matrix. The course of photochemical reactions, studied by FTIR spectroscopy, is slow and inefficient in chitosan with CBD, even under high-energy UV sources. The research also included chitosan films with CBD cross-linked with dialdehyde starch (DAS). Using AFM microscopy and contact angle measurements, the morphology and surface properties of prepared chitosan films with CBD were investigated, respectively. It was found that CBD embedded in CS is characterized by the best photostability under the influence of an LED emitting long-wave radiation. Using a monochromatic and polychromatic UV lamp (HPK and UV-C) emitting high-energy radiation, gradual degradation accompanied by oxidation was observed, both in the CS chains and in the CBD additive. Additionally, changes in surface properties are observed during UV irradiation. It was concluded that CS protects CBD against photodegradation, and a further improvement in photochemical stability is achieved after system cross-linking with DAS.

Application of Chitosan-Based Hydrogel in Promoting Wound Healing: A Review

Chitosan is a linear polyelectrolyte with active hydroxyl and amino groups that can be made into chitosan-based hydrogels by different cross-linking methods. Chitosan-based hydrogels also have a three-dimensional network of hydrogels, which can accommodate a large number of aqueous solvents and biofluids. CS, as an ideal drug-carrying material, can effectively encapsulate and protect drugs and has the advantages of being nontoxic, biocompatible, and biodegradable. These advantages make it an ideal material for the preparation of functional hydrogels that can act as wound dressings for skin injuries. This review reports the role of chitosan-based hydrogels in promoting skin repair in the context of the mechanisms involved in skin injury repair. Chitosan-based hydrogels were found to promote skin repair at different process stages. Various functional chitosan-based hydrogels are also discussed.

Fabrication and characterization of an antibacterial chitosan-coated allantoin-loaded NaCMC/SA skin scaffold for wound healing applications

The field of tissue engineering has recently emerged as one of the most promising approaches to address the limitations of conventional tissue replacements for severe injuries. This study introduces a chitosan-coated porous skin scaffold based on sodium carboxymethyl cellulose (NaCMC) and sodium alginate (SA) hydrogels, incorporating allantoin (AL) as an antibacterial agent. The NaCMC/SA hydrogel was cross-linked with epichlorohydrin (ECH) and freeze-dried to obtain a three-dimensional porous structure. The coated and non-coated scaffolds underwent comprehensive evaluation and characterization through various in-vitro analyses, including SEM imaging, swelling, degradation, and mechanical assessments. Furthermore, the scaffolds were studied regarding their allantoin (AL) release profiles, antibacterial properties, cell viability, and cell adhesion. The in-vitro analyses revealed that adding a chitosan (CS) coating and allantoin (AL) to the NaCMC/SA hydrogel significantly improved the scaffolds' antibacterial properties and cell viability. It was observed that the NaCMC:SA ratio and ECH concentration influenced the swelling capacity, biodegradation, drug release profile, and mechanical properties of the scaffolds. Samples with higher NaCMC content exhibited enhanced swelling capacity, more controlled allantoin (AL) release, and improved mechanical strength. Furthermore, the in-vivo results demonstrated that the proposed skin scaffold exhibited satisfactory biocompatibility and supported cell viability during wound healing in Wistar rats, highlighting its potential for clinical applications.

Biomass-based single- and double-network hydrogels derived from cellulose microfiber and chitosan for potential application as plant growing substrate

A series of hydrogels were synthesized from renewable and low-cost micro-sized cellulose fiber. The single-network hydrogel was composed of cellulose fiber and a small amount of another polysaccharide, chitosan, which 'glued' individual cellulose fiber pieces together through Schiff-base bonding. The double-network hydrogel was constructed by adding a secondary network, the covalently crosslinked polyacrylamide, into the single-network hydrogel, which was synthesized by conducting Schiff-base reaction and free radical polymerization at the same time in a facile one-pot process. In both single- and double-network hydrogels, cellulose fiber constituted the dominant component. Both types of hydrogels exhibited good swelling properties. The double-network hydrogel showed much improved stability against soaking in water and higher salt tolerance. Germination experiment with choy sum seeds sowed on hydrogel surface showed that the seeds were able to germinate and further develop roots, shoots, and true leaves, demonstrating the potential of the biomass-derived hydrogels for soilless plant growing applications.

Evaluation of the Effect of Honey-Containing Chitosan/Hyaluronic Acid Hydrogels on Wound Healing

The 3D polymeric network structure of hydrogels imitates the extracellular matrix, thereby facilitating cell growth and differentiation. In the current study, chitosan/hyaluronic acid/honey coacervate hydrogels were produced without any chemicals or crosslinking agents and investigated for their wound-healing abilities. Chitosan/hyaluronic acid/honey hydrogels were characterized by FTIR, SEM, and rheology analysis. Moreover, their water content, water uptake capacities, and porosity were investigated. In FT-IR spectra, it was discovered that the characteristic band placement of chitosan with hyaluronic acid changed upon interacting with honey. The porosity of the honey-containing hydrogels (12%) decreased compared to those without honey (17%). Additionally, the water-uptake capacity of honey-containing hydrogels slightly decreased. Also, it was observed that hydrogels' viscosity increased with the increased hyaluronic acid amount and decreased with the amount of honey. The adhesion and proliferation of fibroblast cells on the surface of hydrogel formulations were highest in honey-containing hydrogels (144%). In in vivo studies, wound healing was accelerated by honey addition. It has been demonstrated for the first time that honey-loaded chitosan-hyaluronic acid hydrogels, prepared without the use of toxic covalent crosslinkers, have potential for use in wound healing applications.

TiO2, CeO2, and TiO2-CeO2 nanoparticles incorporated 2.5D chitosan hydrogels: Gelation behavior and cytocompatibility

In this study, gelation behavior and cytocompatibility of 2.5D chitosan hydrogels were investigated in the presence of TiO2, CeO2 and TiO2-CeO2 composite nanoparticles. Chemical co-precipitation method was used for nanoparticle synthesis and they were heat treated at 600 °C and 700 °C. Gelation of the chitosan solutions was carried out at 37 °C in the presence of glycerol phosphate and genipin as crosslinkers. The gelation time of chitosan was decreased by all of the nanoparticles whereas its elastic modulus was increased by nanoparticles addition. Chitosan solutions containing CeO2 or TiO2-CeO2 nanoparticles showed faster gel formation compared to chitosan solutions containing only TiO2 nanoparticles. CeO2@700 °C nanoparticles decreased the gelation time by 46% and increased elastic modulus by 14%. Average pore diameter of the hydrogel decreased from 127 ± 62 μm to 77 ± 33 μm, water uptake decreased 21% and thermal stability increased in the presence of CeO2@700 °C nanoparticles compared to chitosan hydrogel. Cell viability results indicated that chitosan hydrogels with or without nanoparticles created 2.5D environment supporting cellular proliferation approximately 1.5 times more than TCPS due to their high porous surfaces. Immunofluorescence images were also supported cell viability results. Therefore, CeO2 or TiO2-CeO2 composite nanoparticles incorporated 2.5D chitosan hydrogels may be alternative tissue engineering materials with their fast gelation, ease of use, low cost, light transparency, and cytocompatibility.

Tough polyvinyl alcohol-gelatin biological macromolecules ionic hydrogel temperature, humidity, stress and strain, sensors

High strength, high toughness and high sensitivity were some of the most popular characteristics of flexible sensors. However, the mechanical properties and reproducibility of current single biomacromolecule gelatin hydrogel sensors are lower, and few hydrogel sensors have been able to provide excellent mechanical properties and flexibility at the same time so far. To address this challenge, a simple method to prepare tough polyvinyl alcohol (PVA) and gelatin hydrogel was proposed in this study. The PVA-gelatin-Fe3+ biological macromolecules hydrogel was prepared by a freeze-casting-assisted solution substitution method, which exhibited high strength (2.5 MPa), toughness (7.22 MJ m-3), and excellent temperature, humidity, stress, strain, and human motion sensing properties. This combination of mechanical properties and flexibility makes PVA-gelatin biological macromolecules hydrogel a promising material for flexible sensing. In addition, an ionic immersion strategy could also impart multiple functions to the hydrogel and be applied to various hydrogel sensor materials. Thus, this work provided an all-around solution for the preparation of advanced and robust sensors with good application prospects.

3D-Printed Chitosan-Based Hydrogels Loaded with Levofloxacin for Tissue Engineering Applications

Herein, we demonstrate the feasibility of a three-dimensional printed chitosan (CS)-poly(vinyl alcohol) (PVA)-gelatin (Gel) hydrogel incorporating the antimicrobial drug levofloxacin (LEV) as a potential tissue engineering scaffold. Hydrogels were prepared by physically cross-linking the polymers, and the printability of the prepared hydrogels was determined. The hydrogel with 3% w/v of CS, 3% w/v of PVA, and 2% w/v of Gel presented the best printability, producing smooth and uniform scaffolds. The integrity of 3D-printed scaffolds was improved via a neutralization process since after testing three different neutralized agents, i.e., NH3 vapors, EtOH/NaOH, and KOH solutions. It was proved that the CS/PVA/Gel hydrogel was formed by hydrogen bonds and remained amorphous in the 3D-printed structures. Drug loading studies confirmed the successful incorporation of LEV, and its in vitro release continued for 48 h. The cytotoxicity/cytocompatibility tests showed that all prepared scaffolds were cytocompatible.

Progress in the Preparation of Stimulus-Responsive Cellulose Hydrogels and Their Application in Slow-Release Fertilizers

Agriculture is facing challenges such as water scarcity, low fertilizer utilization, food security and environmental sustainability. Therefore, the development of slow-release fertilizer (SRF) with controlled water retention and release is particularly important. Slow-release fertilizer hydrogel (SRFH) has a three-dimensional (3D) network structure combined with fertilizer processing, displaying excellent hydrophilicity, biocompatibility and controllability. Cellulose has abundant hydroxyl groups as well as outstanding biodegradability and special mechanical properties, which make it a potential candidate material for the fabrication of hydrogels. This work would analyze and discuss various methods for preparing stimulus-responsive cellulose hydrogels and their combinations with different fertilizers. Moreover, the application and release mechanism of stimulus-responsive cellulose hydrogels in SRF have been summarized as well. Finally, we would explore the potential issues of stimulus-responsive cellulose hydrogels serving as an SRF, propose reasonable solutions and give an outlook of the future research directions.

Synthesis of an insulin-loaded mucoadhesive nanoparticle designed for intranasal administration: focus on new diffusion media

Intranasal administration is a drug delivery approach to provide a non-invasive pharmacological response in the central nervous system with relatively small peripheral side effects. To improve the residence time of intranasal drug delivery systems in the nasal mucosa, mucoadhesive polymers (e.g., chitosan) can be used. Here, insulin-loaded chitosan nanoparticles were synthesized and their physiochemical properties were evaluated based on requirements of intranasal administration. The nanoparticles were spherical (a hydrodynamic diameter of 165.3 nm, polydispersity index of 0.24, and zeta potential of +21.6 mV) that granted mucoadhesion without any noticeable toxicity to the nasal tissue. We applied a new approach using the Krebs-Henseleit buffer solution along with simulated nasal fluid in a Franz's diffusion cell to study this intranasal drug delivery system. We used the Krebs-Henseleit buffer because of its ability to supply glucose to the cells which serves as a novel ex vivo diffusion medium to maintain the viability of the tissue during the experiment. Based on diffusion rate and histopathological endpoints, the Krebs-Henseleit buffer solution can be a substituent solution to the commonly used simulated nasal fluid for such drug delivery systems.

Chitosan-Collagen Electrospun Nanofibers Loaded with Curcumin as Wound-Healing Patches

Composite chitosan-collagen nanofibrous mats embedded with curcumin were prepared via a single-step electrospinning procedure and explored as wound-healing patches with superior biological activity. A mild crosslinking protocol consisting of a short exposure to ammonia vapor and UV radiation was developed to ensure proper stability in physiological-like conditions without affecting the intrinsic biocompatibility of chitosan and collagen. The fabricated composite patches displayed a highly porous, homogeneous nanostructure consisting of fibers with an average diameter of 200 nm, thermal stability up to 200 °C, mechanical features able to ensure protection and support to the new tissues, and water-related properties in the ideal range to allow exudate removal and gas exchange. The release kinetic studies carried out in a simulated physiological environment demonstrated that curcumin release was sustained for 72 h when the mats are crosslinked hence providing prolonged bioactivity reflected by the displayed antioxidant properties. Remarkably, combining chitosan and collagen not only ensures prolonged stability and optimal physical-chemical properties but also allows for better-promoting cell adhesion and proliferation and enhanced anti-bacteriostatic capabilities with the addition of curcumin, owing to its beneficial anti-inflammatory effect, ameliorating the attachment and survival/proliferation rates of keratinocytes and fibroblasts to the fabricated patches.

The Diamond Concept Enigma: Recent Trends of Its Implementation in Cross-linked Chitosan-Based Scaffolds for Bone Tissue Engineering

An increasing number of publications over the past ten years have focused on the development of chitosan-based cross-linked scaffolds to regenerate bone tissue. The design of biomaterials for bone tissue engineering applications relies heavily on the ideals set forth by a polytherapy approach called the "Diamond Concept". This methodology takes into consideration the mechanical environment, scaffold properties, osteogenic and angiogenic potential of cells, and benefits of osteoinductive mediator encapsulation. The following review presents a comprehensive summarization of recent trends in chitosan-based cross-linked scaffold development within the scope of the Diamond Concept, particularly for nonload-bearing bone repair. A standardized methodology for material characterization, along with assessment of in vitro and in vivo potential for bone regeneration, is presented based on approaches in the literature, and future directions of the field are discussed.

Development of chitosan-based hydrogels for healthcare: A review

Chitosan-based hydrogels (CSH) are promising materials for healthcare. Based on the relationship among structure, property and application, researches reported within last decade are chosen to elucidate the developing approaches and potential applications of target CSH. The applications of CSH are classified into the conventional biomedical fields, such as drug controlled release, tissue repair and monitoring, and the essential ones including food safety, water purification and air cleaning. The approaches focused on in this article are the reversible chemical and physical ones. Apart from describing the current status of the development, suggestions are presented as well.

Preparation and Properties of Self-Cross-Linking Hydrogels Based on Chitosan Derivatives and Oxidized Sodium Alginate

A self-cross-linking and biocompatible hydrogel has wide application potential in the field of tissue engineering. In this work, an easily available, biodegradable, and resilient hydrogel was prepared using a self-cross-linking method. This hydrogel was composed of N-2-hydroxypropyl trimethyl ammonium chloride chitosan (HACC) and oxidized sodium alginate (OSA). A stable and reversible cross-linking network was formed by the Schiff base self-cross-linked and hydrogen bonding. The addition of a shielding agent (NaCl) may weaken the intense electrostatic effect between HACC and OSA and solve the problem of flocculation caused by the rapid formation of ionic bonds, which provided an extended time for the Schiff base self-cross-linked reaction for forming a homogeneous hydrogel. Interestingly, the shortest time for the formation of the HACC/OSA hydrogel was within 74 s and the hydrogel had a uniform porous structure and enhanced mechanical properties. The HACC/OSA hydrogel withstood large compression deformation due to improved elasticity. What's more, this hydrogel possessed favorable swelling property, biodegradation, and water retention. The HACC/OSA hydrogels have great antibacterial properties against Staphylococcus aureus and Escherichia coli and demonstrated good cytocompatibility as well. The HACC/OSA hydrogels have a good sustained release effect on rhodamine (model drug). Thus, the obtained self-cross-linked HACC/OSA hydrogels in this study have potential applications in the field of biomedical carriers.

Polysaccharides and Structural Proteins as Components in Three-Dimensional Scaffolds for Breast Cancer Tissue Models: A Review

Breast cancer is the most common cancer among women, and even though treatments are available, efficiency varies with the patients. In vitro 2D models are commonly used to develop new treatments. However, 2D models overestimate drug efficiency, which increases the failure rate in later phase III clinical trials. New model systems that allow extensive and efficient drug screening are thus required. Three-dimensional printed hydrogels containing active components for cancer cell growth are interesting candidates for the preparation of next generation cancer cell models. Macromolecules, obtained from marine- and land-based resources, can form biopolymers (polysaccharides such as alginate, chitosan, hyaluronic acid, and cellulose) and bioactive components (structural proteins such as collagen, gelatin, and silk fibroin) in hydrogels with adequate physical properties in terms of porosity, rheology, and mechanical strength. Hence, in this study attention is given to biofabrication methods and to the modification with biological macromolecules to become bioactive and, thus, optimize 3D printed structures that better mimic the cancer cell microenvironment. Ink formulations combining polysaccharides for tuning the mechanical properties and bioactive polymers for controlling cell adhesion is key to optimizing the growth of the cancer cells.

A comprehensive review of chitosan applications in paper science and technologies

Using environmentally friendly biomaterials in different aspects of human life has been considered extensively. In this respect, different biomaterials have been identified and different applications have been found for them. Currently, chitosan, the well-known derivative of the second most abundant polysaccharide in the nature (i.e., chitin), has been receiving a lot of attention. This unique biomaterial can be defined as a renewable, high cationic charge density, antibacterial, biodegradable, biocompatible, non-toxic biomaterial with high compatibility with cellulose structure, where it can be used in different applications. This review takes a deep and comprehensive look at chitosan and its derivative applications in different aspects of papermaking.

Functionalized Hydrogel-Based Wearable Gas and Humidity Sensors

Breathing is an inherent human activity; however, the composition of the air we inhale and gas exhale remains unknown to us. To address this, wearable vapor sensors can help people monitor air composition in real time to avoid underlying risks, and for the early detection and treatment of diseases for home healthcare. Hydrogels with three-dimensional polymer networks and large amounts of water molecules are naturally flexible and stretchable. Functionalized hydrogels are intrinsically conductive, self-healing, self-adhesive, biocompatible, and room-temperature sensitive. Compared with traditional rigid vapor sensors, hydrogel-based gas and humidity sensors can directly fit human skin or clothing, and are more suitable for real-time monitoring of personal health and safety. In this review, current studies on hydrogel-based vapor sensors are investigated. The required properties and optimization methods of wearable hydrogel-based sensors are introduced. Subsequently, existing reports on the response mechanisms of hydrogel-based gas and humidity sensors are summarized. Related works on hydrogel-based vapor sensors for their application in personal health and safety monitoring are presented. Moreover, the potential of hydrogels in the field of vapor sensing is elucidated. Finally, the current research status, challenges, and future trends of hydrogel gas/humidity sensing are discussed.

Porous Chitosan Hydrogels Produced by Physical Crosslinking: Physicochemical, Structural, and Cytotoxic Properties

Chitosan hydrogels are biomaterials with excellent potential for biomedical applications. In this study, chitosan hydrogels were prepared at different concentrations and molecular weights by freeze-drying. The chitosan sponges were physically crosslinked using sodium bicarbonate as a crosslinking agent. The X-ray spectroscopy (XPS and XRD diffraction), equilibrium water content, microstructural morphology (confocal microscopy), rheological properties (temperature sweep test), and cytotoxicity of the chitosan hydrogels (MTT assay) were investigated. XPS analysis confirmed that the chitosan hydrogels obtained were physically crosslinked using sodium bicarbonate. The chitosan samples displayed a semi-crystalline nature and a highly porous structure with mean pore size between 115.7 ± 20.5 and 156.3 ± 21.8 µm. In addition, the chitosan hydrogels exhibited high water absorption, showing equilibrium water content values from 23 to 30 times their mass in PBS buffer and high thermal stability from 5 to 60 °C. Also, chitosan hydrogels were non-cytotoxic, obtaining cell viability values ≥ 100% for the HT29 cells. Thus, physically crosslinked chitosan hydrogels can be great candidates as biomaterials for biomedical applications.

Biodegradable Hydrogels Based on Chitosan and Pectin for Cisplatin Delivery

Preparation of stable hydrogels using physically (electrostatically) interacting charge-complementary polyelectrolyte chains seems to be more attractive from a practical point of view than the use of organic crosslinking agents. In this work natural polyelectrolytes-chitosan and pectin-were used, due to their biocompatibility and biodegradability. The biodegradability of hydrogels is confirmed by experiments with hyaluronidase as an enzyme. It has been shown that the use of pectins with different molecular weights makes it possible to prepare hydrogels with different rheological characteristics and swelling kinetics. These polyelectrolyte hydrogels loaded with cytostatic cisplatin as a model drug provide an opportunity for its prolonged release, which is important for therapy. The drug release is regulated to a certain extent by the choice of hydrogel composition. The developed systems can potentially improve the effects of cancer treatment due to the prolonged release of cytostatic cisplatin.

Wearable Smart Bandage-Based Bio-Sensors

Bandage is a well-established industry, whereas wearable electronics is an emerging industry. This review presents the bandage as the base of wearable bioelectronics. It begins with introducing a detailed background to bandages and the development of bandage-based smart sensors, which is followed by a sequential discussion of the technical characteristics of the existing bandages, a more practical methodology for future applications, and manufacturing processes of bandage-based wearable biosensors. The review then elaborates on the advantages of basing the next generation of wearables, such as acceptance by the customers and system approvals, and disposal.

Recent progressions in biomedical and pharmaceutical applications of chitosan nanoparticles: A comprehensive review

Nowadays, the most common approaches in the prognosis, diagnosis, and treatment of diseases are along with undeniable limitations. Thus, the ever-increasing need for using biocompatible natural materials and novel practical modalities is required. Applying biomaterials, such as chitosan nanoparticles (CS NPs: FDA-approved long-chain polymer of N-acetyl-glucosamine and D-glucosamine for some pharmaceutical applications), can serve as an appropriate alternative to overcome these limitations. Recently, the biomedical applications of CS NPs have extensively been investigated. These NPs and their derivatives can not only prepare through different physical and chemical approaches but also modify with various molecules and bioactive materials. The potential properties of CS NPs, such as biocompatibility, biodegradability, serum stability, solubility, non-immunogenicity, anti-inflammatory properties, appropriate pharmacokinetics and pharmacodynamics, and so forth, have made them excellent candidates for biomedical applications. Therefore, CS NPs have efficiently applied for various biomedical applications, like regenerative medicine and tissue engineering, biosensors for the detection of microorganisms, and drug delivery systems (DDS) for the suppression of diseases. These NPs possess a high level of biosafety. In summary, CS NPs have the potential ability for biomedical and clinical applications, and it would be remarkably beneficial to develop new generations of CS-based material for the future of medicine.

Recent advances in sustainable nature-based functional materials for biomedical sensor technologies

The lightweight, low-density, and low-cost natural polymers like cellulose, chitosan, and silk have good chemical and biodegradable properties due to their individually unique structural and functional elements. However, the mechanical properties of these polymers differ from each other. In this scenario, chitosan lacks good mechanical properties than cellulose and silk. The synthesis of nano natural polymer and reinforcement with suitable chemical compounds as the development of nanocomposite gives them promising multidisciplinary applications. Many kinds of research are already published with innovative bio-derived polymeric functional materials (Bd-PFM) applications. Most research interest is carried out on health concerns. Lots of attention has been paid to biomedical applications of Bd-PFM as biosensors. This review aims to provide a glimpse of the nanostructures Bd-PFM biosensors.

Chitosan Based Materials in Cosmetic Applications: A Review

This review provides a report on the properties and recent advances in the application of chitosan and chitosan-based materials in cosmetics. Chitosan is a polysaccharide that can be obtained from chitin via the deacetylation process. Chitin most commonly is extracted from cell walls in fungi and the exoskeletons of arthropods, such as crustaceans and insects. Chitosan has attracted significant academic interest, as well as the attention of the cosmetic industry, due to its interesting properties, which include being a natural humectant and moisturizer for the skin and a rheology modifier. This review paper covers the structure of chitosan, the sources of chitosan used in the cosmetic industry, and the role played by this polysaccharide in cosmetics. Future aspects regarding applications of chitosan-based materials in cosmetics are also mentioned.

Advances and Progress in Self-Healing Hydrogel and Its Application in Regenerative Medicine

A hydrogel is a three-dimensional structure that holds plenty of water, but brittleness largely limits its application. Self-healing hydrogels, a new type of hydrogel that can be repaired by itself after external damage, have exhibited better fatigue resistance, reusability, hydrophilicity, and responsiveness to environmental stimuli. The past decade has seen rapid progress in self-healing hydrogels. Self-healing hydrogels can automatically self-repair after external damage. Different strategies have been proposed, including dynamic covalent bonds and reversible noncovalent interactions. Compared to traditional hydrogels, self-healing gels have better durability, responsiveness, and plasticity. These features allow the hydrogel to survive in harsh environments or even to be injected as a drug carrier. Here, we summarize the common strategies for designing self-healing hydrogels and their potential applications in clinical practice.

A Composite of Hydrogel Alginate/PVA/r-GO for Scaffold Applications with Enhanced Degradation and Biocompatibility Properties

We reported in this study the interrelation between the addition of 0.4, 0.8, 1.2, and 1.6 wt. % reduced graphene oxide (r-GO) into PVA/Alginate and their degradation and biocompatibility properties. The r-GO was synthesized by using the Hummer's method. A crosslinker CaSO₄ was added to prepare Alginate/PVA/r-GO Hydrogel composite. A Field Emission in Lens (FEI)-scanning electron microscopy (SEM), along with X-ray energy dispersive spectroscopy (EDS), was performed, characterizing the morphology of the composite. A compressive test was conducted, determining the mechanical properties of the composite with the highest achieved 0.0571 MPa. Furthermore, in vitro cytotoxicity was conducted to determine the biocompatibility properties of the studied composite. An MTT assay was applied to measure cell viability. In general, the presence of r-GO was found to have no significant effect on the morphology of the hydrogel. Indeed, adding 0.4% r-GO to the PVA/Alginate increased the cell viability up to 122.26 ± 0.93, indicating low toxicity. The studied composites have almost no changes in weight and shape, which proves that low degradation occurred in addition to this after 28 days of immersion in saline phosphate buffer solution. In conclusion, achieving minimal degradation and outstanding biocompatibility lead to PVA/Alginate/r-GO hydrogel composites being the most attractive materials for tissue engineering applications.

Biocompatibility and Mechanical Properties of Carboxymethyl Chitosan Hydrogels

Hydrogels have the properties of solid substances and are useful for medicine, e.g., in systems for the controlled release of drugs or as wound dressings. They isolate the wound from the external environment and constitute a barrier to microorganisms while still being permeable to oxygen. In the current study, hydrogels were formed from concentrated aqueous solutions of carboxymethyl chitosan (CMCS) via electron beam irradiation, with the presence of a crosslinking agent: poly(ethylene glycol)diacrylate. The aim of the study was to compare the properties and action of biopolymer CMCS hydrogels with commercial ones and to select the best compositions for future research towards wound-dressing applications. The elasticity of the gel depended on the component concentrations and the irradiation dose employed to form the hydrogel. Young's modulus for the tested hydrogels was higher than for the control material. The Live/Dead test performed on human fibroblasts confirmed that the analyzed hydrogels are not cytotoxic, and for some concentrations, they cause a slight increase in the number of cells compared to the control. The biocompatibility studies carried out on laboratory rats showed no adverse effect of hydrogels on animal tissues, confirming their biocompatibility and suggesting that CMCS hydrogels could be considered as wound-healing dressings in the future. Ionizing radiation was proven to be a suitable tool for CMCS hydrogel synthesis and could be of use in wound-healing therapy, as it may simultaneously sterilize the product.

Efficiency Analysis of Fuel Cell Components with Ionic Poly-Arylether Composite Membrane

We use polyethylene glycol as an additive to explore how the hydrogen bonding of this additive changes the properties of SA8 blended sulfonated polyetheretherketone (SPEEK) composite films. We mixed a 5%wt polyethylene glycol solution into a 12.5%wt SA8 solution, and then prepared a film with a total weight of 40 g at a ratio of 1:99. The SA8 (PEG) solution was prepared and then mixed with 5%wt SPEEK solution, and a film-forming solution with a total weight of 8g in different mixing ratios was created. Polyethylene glycol (PEG) was mixed into the sulfonated polyarylether polymer SA8 to form physical cross-linking. Therefore, the sulfonated polyether ether ketone SPEEK was mixed in, and it exhibited good thermal stability and dimensional stability. However, there was some decrease in proton conductivity as the proportion of SPEEK increased. Although SPEEK mixed with sulfonated polymer reduces the proton conductivity, the physical cross-linking of PEG can improve the proton conductivity of the composite membrane, and adding SPEEK can not only solve the problem of the high sulfonation film swelling phenomenon, it can also improve the dimensional stability of the film through the hydrogen bonding force of PEG and obtain a composite film with excellent properties.