Polyvinyl alcohol/carboxymethyl chitosan hydrogel loaded with silver nanoparticles exhibited antibacterial and self-healing properties

Multilayered hydrogel scaffold construct with native tissue matched elastic modulus: A regenerative microenvironment for urethral scar-free healing

The unsuitable deformation stimulus, harsh urine environment, and lack of a regenerative microenvironment (RME) prevent scaffold-based urethral repair and ultimately lead to irreversible urethral scarring. The researchers clarify the optimal elastic modulus of the urethral scaffolds for urethral repair and design a multilayered PVA hydrogel scaffold for urethral scar-free healing. The inner layer of the scaffold has self-healing properties, which ensures that the wound effectively resists harsh urine erosion, even when subjected to sutures. In addition, the scaffold's outer layer has an extracellular matrix-like structure that synergizes with adipose-derived stem cells to create a favorable RME. In vivo experiments confirm successful urethral scar-free healing using the PVA multilayered hydrogel scaffold. Further mechanistic study shows that the PVA multilayer hydrogel effectively resists the urine-induced inflammatory response and accelerates the transition of urethral wound healing to the proliferative phase by regulating macrophage polarization, thus providing favorable conditions for urethral scar-free healing. This study provides mechanical criteria for the fabrication of urethral tissue-engineered scaffolds, as well as important insights into their design.

Building covalent crosslinks of carboxymethyl konjac glucomannan with boronic ester bonds for fabricating multimodal hydrogel sensor

As the derivative of konjac glucomannan (KGM), carboxymethyl konjac glucomannan (CMK) has attracted increasing attention in the polysaccharide hydrogel fields with the aim of improving the performance related to drug delivery and release. In this study, we prepared a CMK-based hydrogel with dual characteristic crosslinks, and unlocked new applications of this type of hydrogel in soft sensor fields. CMK and poly (vinyl alcohol) were used as substrates, and physical crosslinks were constructed via the freeze-thawing treatments and covalent crosslinks were built via the boronic ester bonding. As-prepared hydrogel possessed significantly improved mechanical performance because the boronic ester bonding, on the one hand, well associated the two kinds of polymer chains, and on the other hand, played the role of 'sacrificial crosslinks'. Furthermore, the occurrence of dynamic boronic ester bonding gave the hydrogel strain- and temperature-sensitive ionic conductivity, and therefore, the hydrogels could be used to identify human motions and as-resulted environmental temperature alterations, and worked well in various scenarios. This work activates new application of CMK in the multimodal sensing field, and also proposes an intriguing way of building multiple crosslinks in the KGM derivative-based hydrogels.

Multifunctional pH-responsive hydrogel dressings based on carboxymethyl chitosan: Synthesis, characterization fostering the wound healing

Antibiotic abuse is increasing the present rate of drug-resistant bacterial wound infections, producing a significant healthcare burden globally. Herein, we prepared a pH-responsive CMCS/PVP/TA (CPT) multifunctional hydrogel dressing by embedding the natural plant extract TA as a nonantibiotic and cross-linking agent in carboxymethyl chitosan (CMCS) and polyvinylpyrrolidone (PVP) to prompt wound healing. The CPT hydrogel demonstrated excellent self-healing, self-adaptive, and adhesion properties to match different wound requirements. Importantly, this hydrogel showed pH sensitivity and exhibited good activity against resistant bacteria and antioxidant activity by releasing TA in case of bacterial infection (alkaline). Furthermore, the CPT hydrogel exhibited coagulant ability and could rapidly stop bleeding within 30 s. The biocompatible hydrogel effectively accelerated wound healing in a full-thickness skin defect model by thickening granulation tissue, increasing collagen deposition, vascular proliferation, and M2-type macrophage polarization. In conclusion, this study demonstrates that multifunctional CPT hydrogel offers a candidate material with potential applications for infected skin wound healing.

Chitosan-based self-healing hydrogel dressing for wound healing

Skin has strong self-regenerative capacity, while severe skin defects do not heal without appropriate treatment. Therefore, in order to cover the wound sites and hasten the healing process, wound dressings are required. Hydrogels have emerged as one of the most promising candidates for wound dressings because of their hydrated and porous molecular structure. Chitosan (CS) with biocompatibility, oxygen permeability, hemostatic and antimicrobial properties is beneficial for wound treatment and it can generate self-healing hydrogels through reversible crosslinks, from dynamic covalent bonding, such as Schiff base bonds, boronate esters, and acylhydrazone bonds, to physical interactions like hydrogen bonding, electrostatic interaction, ionic bonding, metal-coordination, host-guest interactions, and hydrophobic interaction. Therefore, various chitosan-based self-healing hydrogel dressings have been prepared in recent years to cope with increasingly complex wound conditions. This review's objective is to provide comprehensive information on the self-healing mechanism of chitosan-based hydrogel wound dressings, discuss their advanced functions including antibacterial, conductive, anti-inflammatory, anti-oxidant, stimulus-responsive, hemostatic/adhesive and controlled release properties, further introduce their applications in the promotion of wound healing in two categories: acute and chronic (infected, burn and diabetic) wounds, and finally discuss the future perspective of chitosan-based self-healing hydrogel dressings for wound healing.

Polysaccharide- and protein-based hydrogel dressings that enhance wound healing: A review

Hydrogels can possess desired biochemical and mechanical properties, excellent biocompatibility, satisfactory biodegradability, and biological capabilities that promote skin repair, making them ideal candidates for skin healing dressings. Polysaccharides, such as chitosan, hyaluronic acid and sodium alginate as well as proteins, including gelatin, collagen and fibroin proteins, are biological macromolecules celebrated for their biocompatibility and biodegradability, are at the forefront of innovative hydrogel dressing development. This work first summarizes the skin wound healing process and its influencing factors, and then systematically articulates the multifunctional roles of hydrogels based on biological macromolecules (polysaccharides and proteins) as dressing in addressing bacterial infection, hemorrhage and inflammation during wound healing. Furthermore, this review explores the potential of these hydrogels as vehicles for combination therapy, by incorporating growth factors or stem cells. Finally, the article offers insights into future directions of such hydrogels in wound repair field.

Medical Applications and Cellular Mechanisms of Action of Carboxymethyl Chitosan Hydrogels

Carboxymethyl chitosan (CMCS) hydrogels have been investigated in biomedical research because of their versatile properties that make them suitable for various medical applications. Key properties that are especially valuable for biomedical use include biocompatibility, tailored solid-like mechanical characteristics, biodegradability, antibacterial activity, moisture retention, and pH stimuli-sensitive swelling. These features offer advantages such as enhanced healing, promotion of granulation tissue formation, and facilitation of neutrophil migration. As a result, CMCS hydrogels are favorable materials for applications in biopharmaceuticals, drug delivery systems, wound healing, tissue engineering, and more. Understanding the interactions between CMCS hydrogels and biological systems, with a focus on their influence on cellular behavior, is crucial for leveraging their versatility. Because of the constantly growing interest in chitosan and its derivative hydrogels in biomedical research and applications, the present review aims to provide updated insights into the potential medical applications of CMCS based on recent findings. Additionally, we comprehensively elucidated the cellular mechanisms underlying the actions of these hydrogels in medical settings. In summary, this paper recapitulates valuable data gathered from the current literature, offering perspectives for further development and utilization of carboxymethyl hydrogels in various medical contexts.

Lentinan-based pH-responsive nanoparticles achieve the combination therapy of tumors

Cancer poses a significant threat to human health, and there is an urgent need for more effective treatments. Combining chemotherapy and immunotherapy is an effective strategy to enhance curative outcomes and holds great potential for widespread application. The natural phytochemical genistein (GEN) exhibits cytotoxicity against tumors and is a potential chemotherapeutic agent. Lentinan (LTN) is a natural polysaccharide with immune-enhancing properties that has been utilized in tumor treatment. This study constructed a pH-responsive nanoparticle GEN@LTN-BDBA with chemotherapy and immunotherapy functions using GEN and LTN. After characterizing the nanoparticles, the molecular mechanism of GEN@LTN-BDBA formation was explored using in silico simulation. GEN@LTN-BDBA can significantly inhibit the proliferation of A549 and HepG2 cells in vitro. The in vivo experiment results demonstrated that treatment with GEN@LTN-BDBA can significantly reduce tumor cell mass and prevent metastasis. In this nanoparticle, GEN induced oxidative stress and apoptosis of tumor cells. Meanwhile, the released LTN initiated an anti-tumor immune response by promoting dendritic cell (DC) maturation and upregulating the expression of costimulatory molecules and major histocompatibility complex. The construction method of GEN@LTN-BDBA can be extended to the preparation of other polysaccharides and hydrophobic chemotherapy molecules, offering a novel strategy to enhance the efficacy of monotherapy.

In-situ forming carboxymethyl chitosan hydrogel containing Paeonia suffruticosa Andr. leaf extract for mixed infectious vaginitis treatment by reshaping the micro-biota

Mixed infectious vaginitis poses a serious threat to female reproductive health due to complex pathogenic factors, a long course and easy recurrence. Currently, antibiotic-based treatment methods are facing a crisis of drug resistance and secondary dysbiosis. Exploring effective drugs for the treatment of mixed vaginitis from Paeonia suffruticosa Andr., a natural traditional Chinese medicine with a long history of medicinal use, is a feasible treatment strategy. P. suffruticosa Andr. leaf extract (PLE) has significant anti-bacterial effects due to its rich content of polyphenols and flavonoids. The polyphenols in peony leaves have the potential to make carboxymethyl chitosan form in situ gel. In the current study, PLE and carboxymethyl chitosan were combined to develop another type of natural anti-bacterial anti-oxidant hydrogel for the treatment of mixed infectious vaginitis. Through a series of characterisations, CP had a three-dimensional network porous structure with good mechanical properties, high water absorption, long retention and a slow-release drug effect. The mixed infectious vaginitis mouse model induced by a mixture of pathogenic bacteria was used to investigate the therapeutic effects of CP in vivo. The appearance of the vagina, H&E colouring of the tissue and inflammatory factors (TNF-α, IL-6) confirm the good anti-vaginal effect of CP. Therefore, CP was expected to become an ideal effective strategy to improve mixed infection vaginitis due to its excellent hydrogel performance and remarkable ability to regulate flora.

Antibacterial Hydrogels for Wound Dressing Applications: Current Status, Progress, Challenges, and Trends

Bacterial infection treatment for chronic wounds has posed a major medical threat and challenge. Bacteria at the wounded sites can compete with the immune system and subsequently invade live tissues, leading to more severe tissue damage. Therefore, there is an urgent demand for wound dressings with antibacterial and anti-inflammatory properties. Considering the concept of moist healing, hydrogels with a three-dimensional (3D) network structure are widely used as wound dressings due to their excellent hydrophilicity, water retention properties, and biocompatibility. Developing antibacterial hydrogels for the treatment of infected wounds has been receiving extensive attention recently. This article categorizes antibacterial hydrogels according to their materials and antibacterial modes, and introduces the recent findings and progress regarding their status. More importantly, with the development of emerging technologies, new therapies are utilized to prepare antibacterial hydrogels such as nanoenzymes, photothermal therapy (PTT), photodynamic therapy (PDT), metal-organic frameworks (MOFs), and other external stimuli-responsive methods. Therefore, this review also examines their progress, challenges, and future trends as wound dressings. In the following studies, there will still be a focus on antibacterial hydrogels that have a high performance, multi-functions, and intelligence, especially biocompatibility, a high and long-lasting antibacterial property, responsiveness, and on-demand therapeutic ability.

Fibroblast alignment and matrix remodeling induced by a stiffness gradient in a skin-derived extracellular matrix hydrogel

Large skin injuries heal as scars. Stiffness gradually increases from normal skin to scar tissue (20x higher), due to excessive deposition and crosslinking of extracellular matrix (ECM) mostly produced by (myo)fibroblasts. Using a custom mold, skin-derived ECM hydrogels (dECM) were UV crosslinked after diffusion of ruthenium (Ru) to produce a Ru-dECM gradient hydrogel. The Ru diffusion gradient equates to a stiffness gradient and models physiology of the scarred skin. Crosslinking in Ru-dECM hydrogels results in a 23-fold increase in stiffness from a stiffness similar to that of normal skin. Collagen fiber density increases in a stiffness-dependent fashion while stress relaxation also alters, with one additional Maxwell element necessary for characterizing Ru-dECM. Alignment of fibroblasts encapsulated in hydrogels suggests that the stiffness gradient directs fibroblasts to orientate at ∼45 ° in regions below 120 kPa. In areas above 120 kPa, fibroblasts decrease the stiffness prior to adjusting their orientation. Furthermore, fibroblasts remodel their surrounding ECM in a gradient-dependent fashion, with rearrangement of cell-surrounding ECM in high-stiffness areas, and formation of interlaced collagen bundles in low-stiffness areas. Overall, this study shows that fibroblasts remodel their local environment to generate an optimal ECM mechanical and topographical environment. STATEMENT OF SIGNIFICANCE: This study developed a versatile in vitro model with a gradient stiffness using skin-derived ECM hydrogel with unchanged biochemical environment. Using Ruthenium crosslinking, a 20-fold stiffness increase was achieved as observed in fibrotic skin. The interaction between fibroblasts and matrix depends on changes in the matrix stiffness. The stiffness gradient directed the alignment of fibroblasts with ∼45° in regions with≤ 120 kPa. The cells in regions with the higher stiffness decreased stiffness first and then oriented themselves. Furthermore, fibroblasts remodeled surrounding ECM and regulated its mechanics in a gradient-dependent fashion to reach an optimal condition. Our study highlights the dynamic interplay between cells and surrounding matrix, shedding light on potential mechanisms and strategies to target scar formation and remodeling.

Synthesis, Characterization, and Evaluation of Silver Nanoparticle-Loaded Carboxymethyl Chitosan with Sulfobetaine Methacrylate Hydrogel Nanocomposites for Biomedical Applications

In this study, nanocomposites of AgNPs encapsulated in carboxymethyl chitosan (CMCS) with sulfobetaine methacrylate (SB) hydrogel (AgNPs/CMCS-SB) were synthesized. The UV-Vis spectra indicated the presence of AgNPs, with a broad peak at around 424 nm, while the AgNPs-loaded CMCS-SB nanocomposite exhibited absorption peaks at 445 nm. The size and dispersion of AgNPs varied with the concentration of the AgNO3 solution, affecting swelling rates: 148.37 ± 15.63%, 172.26 ± 18.14%, and 159.17 ± 16.59% for 1.0 mM, 3.0 mM, and 5.0 mM AgNPs/CMCS-SB, respectively. Additionally, water absorption capacity increased with AgNPs content, peaking at 11.04 ± 0.54% for the 3.0 mM AgNPs/CMCS-SB nanocomposite. Silver release from the nanocomposite was influenced by AgNO3 concentration, showing rapid initial release followed by a slower rate over time for the 3.0 mM AgNPs/CMCS-SB. XRD patterns affirmed the presence of AgNPs, showcasing characteristic peaks indicative of a face-centered cubic (fcc) structure. The FTIR spectra highlighted interactions between AgNPs and CMCS-SB, with noticeable shifts in characteristic bands. In addition, SEM and TEM images validated spherical AgNPs within the CMCS-SB hydrogel network, averaging approximately 70 and 30 nm in diameter, respectively. The nanocomposite exhibited significant antibacterial activity against S. aureus and E. coli, with inhibition rates of 98.9 ± 0.21% and 99.2 ± 0.14%, respectively, for the 3.0 mM AgNPs/CMCS-SB nanocomposite. Moreover, cytotoxicity assays showcased the efficacy of AgNPs/CMCS-SB against human colorectal cancer cells (HCT-116 cells), with the strongest cytotoxicity (61.7 ± 4.3%) at 100 μg/mL. These results suggest the synthesized AgNPs/CMCS-SB nanocomposites possess promising attributes for various biomedical applications, including antimicrobial and anticancer activities, positioning them as compelling candidates for further advancement in biomedicine.

Exudate-Induced Gelatinizable Nanofiber Membrane with High Exudate Absorption and Super Bactericidal Capacity for Bacteria-Infected Wound Management

Invasion of bacteria and continuous oozing of exudate are significant causes of interference with the healing of infected wounds. Therefore, an exudate-induced gelatinizable and near-infrared (NIR)-responsive nanofiber membrane composed of polyvinyl alcohol (PVA), carboxymethyl chitosan (CMC), and Fe-doped phosphomolybdic acid (Fe-PMA) with exceptional exudate absorption capacity and potent bactericidal efficacy is developed and denoted as the PVA-FP-CMC membrane. After absorbing exudate, the fiber membrane can transform into a hydrogel membrane, forming coordination bonds between the Fe-PMA and CMC. The unique exudate-induced gelation process imparts the membrane with high exudate absorption and retention capability, and the formed hydrogel also traps the bacteria that thrive in the exudate. Moreover, it is discovered for the first time that the Fe-PMA exhibits an enhanced photothermal conversion capability and photocatalytic activity compared to the PMA. Therefore, the presence of Fe-PMA provides the membrane with a photothermal and photodynamic therapeutic effect for killing bacteria. The PVA-FP-CMC membrane is proven with a liquid absorption ratio of 520.7%, a light-heat conversion efficiency of 41.9%, high-level generation of hydroxyl radical (•OH) and singlet oxygen (1O2), and a bacterial killing ratio of 100% for S. aureus and 99.6% for E. coli. The treatment of infected wounds on the backs of rats further confirms the promotion of wound healing by the PVA-FP-CMC membrane with NIR irradiation. Overall, this novel functional dressing for the synergistic management of bacteria-infected wounds presents a promising therapeutic strategy for tissue repair and regeneration.

Multifunctional sodium lignosulfonate/xanthan gum/sodium alginate/polyacrylamide ionic hydrogels composite as a high-performance wearable strain sensor

Recently, conductive hydrogels have shown great promise in flexible electronics and are ideal materials for the preparation of wearable strain sensors. However, developing a simple method to produce conductive hydrogels with excellent mechanical properties, self-adhesion, transparency, anti-freezing, and UV resistance remains a significant challenge. A novel sodium lignosulfonate/xanthan gum/sodium alginate/polyacrylamide/Zn2+/DMSO (SLS/XG/SA/PAM/Zn2+/DMSO) ionic conductive hydrogel was developed using a one-pot method. The resulting ionic conductive hydrogels have excellent mechanical properties (stress: 0.13 MPa, strain: 1629 %), high anti-fatigue properties, self-adhesion properties (iron: 7.37 kPa, pigskin: 4.74 kPa), anti-freezing (freezing point: -33.49 °C) and UV resistance by constructing a chemical and physical hybrid cross-linking network. In particular, the conductivity of G hydrogel reached 6.02 S/m at room temperature and 5.52 S/m at -20 °C. Thus, the hydrogel was assembled into a flexible sensor that could distinguish a variety of large and small scales human movements, such as joint bending, swallowing and speaking in real time with high stability and sensitivity. Moreover, the hydrogel could be used as electronic skin just like human skin and touch screen pen to write.

ROS/pH dual responsive PRP-loaded multifunctional chitosan hydrogels with controlled release of growth factors for skin wound healing

Platelet-rich plasma (PRP) contains a variety of growth factors (GFs) and has been used in the treatment of a variety of diseases, including skin lesions. In particular, PRP with low immunogenicity will be more widely used. However, the explosive release of GFs limits its further application. In order to achieve controlled release of GFs, a multifunctional and reactive oxygen species (ROS)/pH dual responsive hydrogel was developed to load PRP derived from human cord blood for the treatment of skin wound healing. Based on the hydrogen bond and Schiff base interaction, carboxymethyl chitosan (CMCS), oxidized dextran (Odex) and oligomeric procyanidins (OPC) were crosslinked to form CMCS/Odex/OPC/PRP hydrogel with good injectability, self-healing, adhesion, ROS scavenging, antibacterial activity, controlled and sustained release of GFs. In vitro cell experiments suggested that this hydrogel possessed excellent biocompatibility and could promote the proliferation and migration of L929. In vivo healing of full-layer skin wounds further indicated that the prepared hydrogel could regulate inflammation and promote epithelialization, collagen deposition, and angiogenesis. In summary, this present study demonstrates that CMCS/Odex/OPC/PRP hydrogel may serve as a promising multifunctional dressing for skin wound healing.

Rapid Preparation of Highly Stretchable and Fast Self-Repairing Antibacterial Hydrogels for Promoting Hemostasis and Wound Healing

Hydrogel dressings have emerged as a vital resource in wound management, offering several advantages over conventional wound dressing materials. Their inherent biocompatibility, ability to replicate the native extracellular matrix, and capacity to provide an ideal environment for cell survival make them particularly valuable. Nevertheless, the mechanical properties of many hydrogel dressings are an area that warrants improvement, as it currently constrains their application range. This limitation is especially evident when skin wounds are addressed in highly active or easily scratched areas. In this study, we present the development of a highly stretchable self-repairing hydrogel by cross-linking poly(vinyl alcohol) (PVA) through dynamic boron ester bonds, coupled with the hydrogen bonding of carboxymethyl cellulose sodium (CMC) via an efficient one-pot method without adding any catalyst. This innovative PVA/CMC hydrogel exhibited remarkable antibacterial properties achieved through the incorporation of bergamot oil, which was dispersed in a β-cyclodextrin solution. The hydrogel's elongation at the point of rupture reached an impressive 1910%, and it was capable of rapid self-healing in just 3 min upon bonding. Additionally, the hydrogel demonstrated excellent hemostatic properties, effectively mitigating blood loss and exudation. In vivo wound models have shown that PVA/CMC significantly expedites wound healing by reducing bacterial infections, inflammatory responses, and blood loss and by promoting collagen deposition. In summary, this research provides crucial insights into its potential as an advanced wound dressing material, particularly well-suited for addressing wounds in places with frequent activities or easy scratches.

Construction of carboxymethyl chitosan/PVA/chitin nanowhiskers multicomponent film activated with Cotylelobium lanceolatum phenolics and in situ SeNP for enhanced packaging application

This work focused on the construction of bioactive packaging films based on carboxymethyl chitosan and poly(vinyl alcohol) (CMP) as polymeric matrix and fortified with chitin nanowhiskers, Cotylelobium lanceolatum phenolic extract (CL) and in situ synthesized nano selenium. Extensive morphological, microstructural, physical and mechanical analysis revealed that the nanofillers were well-dispersed and integrated into CMP matrix. Incorporation of the extract and nano selenium produced excellent UV blocking properties without seriously compromising the transparency of the composite (CMP/CNW/CLNS1) film. Moreover, blending of CMP with the filler materials significantly elevated (p < 0.05) the surface hydrophobicity (WCA by 35.4°), water barrier (by 53.86 %), tensile strength (from 29.35 to 33.09 MPa), elongation at break (from 64.28 to 96.48 %), and thermal properties of the resultant CMP/CNW/CLNS1 film, with concomitant reduction in water solubility and swellability. Furthermore, the CMP/CNW/CLNS films exhibited remarkable improvement in antioxidant properties. When used for packaging of peeled fresh garlic cloves, the CMP/CNW/CLNS1 film pouch, not the plain CMP or CMP/CNW film pouches, inhibited weight loss, oxidative browning, and the emergence of black mold on the packaged cloves. The developed CMP/CNW/CLNS1 film demonstrated enhanced capacity to safeguard the quality of packaged food and improved shelf life. Therefore, the present study suggests that incorporation of CNW/CLNS into carboxymethyl chitosan/PVA films is a suitable and facile strategy for the fabrication of films with improved mechanical, physico-chemical and functional properties with great potential for application as a sustainable active packaging material in the food industry.

Review on chitosan-based antibacterial hydrogels: Preparation, mechanisms, and applications

Chitosan (CS) is known for its remarkable properties, such as good biocompatibility, biodegradability, and renewability, in addition to its antibacterial and biological activities. However, as CS is insoluble in water, it displays limited antibacterial performance under neutral and physiological conditions. A viable solution to this problem is grafting chemically modified groups onto the CS framework, thereby increasing its solubility and enhancing its antibacterial effect. Herein, the antibacterial action mechanism of CS and its derivatives is reviewed, confirming the prevalent use of composite materials comprising CS and its derivatives as an antibacterial agent. Generally, the antimicrobial ability of CS-based biomaterials can be enhanced by incorporating supplementary polymers and antimicrobial agents. Research on CS-based composite biomaterials is ongoing and numerous types of biomaterials have been reported, including inorganic nanoparticles, antibacterial agents, and CS derivatives. The development of these composite materials has considerably expanded the application of CS-based antibacterial materials. This study reviews the latest progress in research regarding CS-based composite hydrogels for wound repair, tissue engineering, drug release, water purification, and three-dimensional printing applications. Finally, the summary and future outlook of CS-based antibacterial hydrogels are presented in anticipation of a broader range of applications of CS-based antibacterial hydrogels.

Carboxymethyl chitosan/polyvinyl alcohol double network hydrogels prepared by freeze-thawing and calcium chloride cross-linking for efficient dye adsorption

The discharge of dye wastewater resulting from rapid industrial development has become a serious environmental concern. Therefore, there is a pressing need to develop efficient methods and technologies for the removal of dye pollutants. This study introduced a double network hydrogel, with varying carboxymethyl chitosan (CMCS) contents and polyvinyl alcohol (PVA), employing a combination of freeze- thawing and calcium chloride cross-linking. The investigation focused on the rheological properties of the hydrogels and their removal ability of acidic blue 93 (AB). The results showed that the strength and viscoelastic modulus of composite hydrogels were positively correlated with the CMCS content, and all composite hydrogels exhibited the typical weak strain overshoot behavior. The pore size of the gel initially decreased and then increased, with the densest pores observed at 4 wt% CMCS, showing the optimal removal ability for AB. The adsorption process followed pseudo second-order kinetic model, dominated by external diffusion, and exhibited inhomogeneous multilayer adsorption. This study unveils the potential of CMCS/PVA gels as adsorbents, offering inspirations for the design and development of polyvinyl alcohol-based gels for applications in the food industry.

Gold@mesoporous polydopamine nanoparticles modified self-healing hydrogel for sport-injuring therapy

Sports-related damage is a prevalent issue, which a combination therapy including photothermal irradiation, self-healing dressing and antibacterial treatment is an effective way to rehabilitate it. In the study, a multifunctional hydrogel was developed to meet the requirement. Firstly, mesoporous polydopamine (MPDA) was prepared, where gold nanoparticles (Au NPs) were formed in its mesoporous structure, to construct Au@MPDA NPs with nanosize about 200 nm. Synergetic and efficient photothermal effect was achieved by the combination of the two photothermal agents. The Au@MPDA NPs were then added to modify polyvinyl alcohol-carboxymethyl chitosan-borax (PCB) hydrogel. Via rheological property characterization, cell experiments and antibacterial evaluation, high photothermal efficiency and effective antibacterial activity of Au@MPDA@PCB hydrogel was obtained with the aid of Au@MPDA NPs, together with self-healing property. When treated in motion-related tissue, the modified hydrogel showed excellent adaptive property and photothermal effect in situ. This study is beneficial for developing a novel rehabilitation treatment strategy for sports-related injuries.

Versatile Injectable Carboxymethyl Chitosan Hydrogel for Immediate Hemostasis, Robust Tissue Adhesion Barrier, and Antibacterial Applications

Iatrogenic ulcers resulting from endoscopic submucosal dissection surgery remain a significant clinical concern due to the risk of uncontrolled bleeding. Herein, we have developed an injectable shear-thinning hydrogel cross-linked through electrostatic interactions and hydrogen bonding. The hydrogel underwent comprehensive characterization, focusing on rheological behavior, injectability, microstructure, film-forming capability, adhesion, swelling behavior, degradation kinetics, antibacterial efficacy, hemostatic performance, and biocompatibility. The incorporation of poly(vinyl alcohol) notably enhanced the internal structural stability and injection pressure, while the Laponite content influenced self-healing ability, modulus, and viscosity. Additionally, the hydrogel exhibited pH sensitivity, appropriate degradation, and swelling rates and displayed favorable film-forming and adhesion properties. Notably, it demonstrated excellent resistance against Escherichia coli and Staphylococcus aureus, highlighting its potential to create an optimal wound environment. In vivo studies further confirmed the hydrogel's exceptional hemostatic performance, positioning it as an optimal material for endoscopic submucosal dissection (ESD) surgery. Moreover, cell experiments and hemolysis tests revealed high biocompatibility, supporting their potential to facilitate the healing of iatrogenic ulcers post-ESD surgery. In conclusion, our hydrogels hold great promise as endoscopic treatment materials for ESD-induced ulcers given their outstanding properties.

Dual-network hydrogels based on dynamic imine and borate ester bonds with antibacterial and self-healing properties

Polymeric hydrogel materials with multiple functions are in great demand in practical biomedical scenarios. In this work, a self-healing hydrogel with both antimicrobial properties was prepared using a strategy that combines dynamic imine and borate ester bonds. In this hydrogel, polyvinyl alcohol (PVA) is used as the base network, and borax solution as the cross-linking agent, and borate ester bonds can be formed between these two. Dialdehyde carboxymethyl cellulose (DCMC) was selected to cross-link with the amino groups in carboxymethyl chitosan (CMCS) and polyethyleneimine (PEI) to form dynamic imine bonds. The PVA/PEI/DCMC/CMCS hydrogels prepared by double chemical cross-linking have good mechanical properties (maximum tensile strength up to 289 KPa and strain at the break up to 1025%). Due to the uniqueness of the two chemical bonds, the hydrogel material is self-healing at room temperature without additional stimulation. In addition, the inherent antibacterial properties of the raw materials in this hydrogel confer antibacterial properties, with a kill rate of up to 99% against E. coli and S. aureus. The multifunctional hydrogels developed in this study provide more ideas and references for the future application of hydrogel materials in practical scenarios.

Chitosan-Based Self-Healing Hydrogel: From Fabrication to Biomedical Application

Biocompatible self-healing hydrogels are new-generation smart soft materials that hold great promise in biomedical fields. Chitosan-based self-healing hydrogels, mainly prepared via dynamic imine bonds, have attracted broad attention due to their mild preparation conditions, excellent biocompatibility, and self-recovery ability under a physiological environment. In this review, we present a comprehensive overview of the design and fabrication of chitosan-based self-healing hydrogels, and summarize their biomedical applications in tissue regeneration, customized drug delivery, smart biosensors, and three/four dimensional (3D/4D) printing. Finally, we will discuss the challenges and future perspectives for the development of chitosan-based self-healing hydrogels in the biomedical field.

A Novel Multifunctional Crosslinking PVA/CMCS Hydrogel Containing Cyclic Peptide Actinomycin X2 and PA@Fe with Excellent Antibacterial and Commendable Mechanical Properties

Bacterial infected environments and resulting bacterial infections have been threatening the human health globally. Due to increased bacterial resistance caused by improper and excessive use of antibiotics, antibacterial biomaterials are being developed as alternatives to antibiotics in some cases. Herein, an advanced multifunctional hydrogel with excellent antibacterial properties, enhanced mechanical properties, biocompatibility and self-healing performance, was designed through freezing-thawing method. This hydrogel network is composed of polyvinyl alcohol (PVA), carboxymethyl chitosan (CMCS), protocatechualdehyde (PA), ferric iron (Fe) and an antimicrobial cyclic peptide actinomycin X2 (Ac.X2). The double dynamic bonds among protocatechualdehyde (PA), ferric iron (Fe) and carboxymethyl chitosan containing coordinate bond (catechol-Fe) as well as dynamic Schiff base bonds and hydrogen bonds endowed the hydrogel with enhanced mechanical properties. Successful formation of hydrogel was confirmed through ATR-IR and XRD, and structural evaluation through SEM analysis, whereas mechanical properties were tested with electromechanical universal testing machine. The resulting PVA/CMCS/Ac.X2/PA@Fe (PCXPA) hydrogel has favorable biocompatibility and excellent broad-spectrum antimicrobial activity against both S. aureus (95.3 %) and E. coli (90.2 %) compared with free-soluble Ac.X2, which exhibited subpar performance against E. coli reported in our previous studies. This work provides a new insight on preparing multifunctional hydrogels containing antimicrobial peptides as antibacterial material.

Application of polyvinyl alcohol/chitosan copolymer hydrogels in biomedicine: A review

Hydrogels is a hydrophilic, cross-linked polymer of three-dimensional network structures. The application of hydrogels prepared from a single polymer in the biomedical field has many drawbacks. The functional blend of polyvinyl alcohol and chitosan allows hydrogels to have better and more desirable properties than those produced from a single polymer, which is a good biomaterial for development and design. In this paper, we have reviewed the progress in the application of polyvinyl alcohol/chitosan composite hydrogels in various medical fields, the different cross-linking agents and cross-linking methods, and the research progress in the optimization of composite hydrogels for their subsequent wide range of biomedical applications.

Advances in Functional Hydrogel Wound Dressings: A Review

One of the most advanced, promising, and commercially viable research issues in the world of hydrogel dressing is gaining functionality to achieve improved therapeutic impact or even intelligent wound repair. In addition to the merits of ordinary hydrogel dressings, functional hydrogel dressings can adjust their chemical/physical properties to satisfy different wound types, carry out the corresponding reactions to actively create a healing environment conducive to wound repair, and can also control drug release to provide a long-lasting benefit. Although a lot of in-depth research has been conducted over the last few decades, very few studies have been properly summarized. In order to give researchers a basic blueprint for designing functional hydrogel dressings and to motivate them to develop ever-more intelligent wound dressings, we summarized the development of functional hydrogel dressings in recent years, as well as the current situation and future trends, in light of their preparation mechanisms and functional effects.

Silver Nanoparticles Loaded on Chitosan-g-PVA Hydrogel for the Wound-Healing Applications

Silver nanoparticle composites have abundant biomedical applications due to their unique antibacterial properties. In the current work, green tea leaf extract was used as a natural reducing agent to synthesize AgNPs (AgNPs) using microwave irradiation technology. Furthermore, microwave irradiation has been used for the preparation of AgNPs/chitosan (Ch) grafted polyvinyl alcohol (PVA) hydrogel samples. To approve the accomplishment of AgNPs hydrogel polymer, UV-spectrum, TEM, and FT-IR spectrum analyses and the release of silver ions, actions were taken. The wound-healing ability of the prepared hydrogel samples was measured via both the in vitro (fibroblast cells) and the in vivo using rat models. It was found that chitosan-grafted polyvinyl alcohol, including AgNPs, exhibited excellent antibacterial activity against E. coli and S. aureus using the agar diffusion method. It can be said that microwave irradiation was successful in creating a hydrogel that contained silver nanoparticles. A wound that was still open was successfully treated with these composites.

Biomaterials Based on Chitosan and Its Derivatives and Their Potential in Tissue Engineering and Other Biomedical Applications-A Review

In the times of dynamically developing regenerative medicine, more and more attention is focused on the use of natural polymers. This is due to their high biocompatibility and biodegradability without the production of toxic compounds, which means that they do not hurt humans and the natural environment. Chitosan and its derivatives are polymers made most often from the shells of crustaceans and are biodegradable and biocompatible. Some of them have antibacterial or metal-chelating properties. This review article presents the development of biomaterials based on chitosan and its derivatives used in regenerative medicine, such as a dressing or graft of soft tissues or bones. Various examples of preparations based on chitosan and its derivatives in the form of gels, films, and 3D structures and crosslinking products with another polymer are discussed herein. This article summarizes the latest advances in medicine with the use of biomaterials based on chitosan and its derivatives and provides perspectives on future research activities.

Fabrication and Characterization of Ag Nanoparticle-embedded κ-Carrageenan-Sodium Alginate Nanocomposite Hydrogels with Potential Antibacterial and Cytotoxic Activities

Hydrogel nanocomposites are attracting increasing attention in field of biology owing to their unique properties. The present work focuses on the fabrication and characterization of novel hydrogel nanocomposite systems in which silver nanoparticles (AgNPs) are embedded in a carrageenan (κ-CGN)-sodium alginate (SA) hydrogel. The performance of the prepared κ-CGN-SA hydrogel and κ-CGN-SA/AgNPs hydrogel nanocomposite was determined by UV-visible spectroscopy, FTIR, XRD, SEM, EDX spectrum, EDX mapping, and TEM analysis. Surface plasmon resonance at 428 nm confirmed the presence of AgNPs in the κ-CGN-SA hydrogel. The results indicate that AgNPs with an average diameter of 30 nm were uniformly dispersed in the κ-CGN-SA hydrogel matrix. The amount of Ag⁺ ion release kinetic from the κ-CGN-SA hydrogel matrix is very low, showing that AgNPs were well trapped within the κ-CGN-SA/AgNPs hydrogel nanocomposite. The high antibacterial activity of the κ-CGN-SA/AgNPs hydrogel nanocomposite was found to be 89.6 ± 1.4% and 91.4 ± 2.3% against the gram-positive S. aureus and the gram-negative E. coli, respectively. Moreover, the κ-CGN-SA/AgNPs hydrogel nanocomposite showed good biocompatibility by the MTT test. The novel κ-CGN-SA/AgNPs hydrogel nanocomposite low cytotoxicity and antibacterial efficacy is proposed as a potential candidate for biomedical applications.

Recent Reports on Polysaccharide-Based Materials for Drug Delivery

Polysaccharides constitute one of the most important families of biopolymers. Natural polysaccharide-based drug delivery systems are of constant interest to the scientific community due to their unique properties: biocompatibility, non-toxicity, biodegradability, and high availability. These promising biomaterials protect sensitive active agents and provide their controlled release in targeted sites. The application of natural polysaccharides as drug delivery systems is also intensively developed by Polish scientists. The present review focuses on case studies from the last few years authored or co-authored by research centers in Poland. A particular emphasis was placed on the diversity of the formulations in terms of the active substance carried, the drug delivery route, the composition of the material, and its preparation method.