Fungal Carboxymethyl Chitosan-Impregnated Bacterial Cellulose Hydrogel as Wound-Dressing Agent

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.

Bio-Composite Films Based on Carboxymethyl Chitosan Incorporated with Calcium Oxide: Synthesis and Antimicrobial Activity

The utilization of biopolymers incorporated with antimicrobial agents is extremely interesting in the development of environmentally friendly functional materials for food packaging and other applications. In this study, the effect of calcium oxide (CaO) on the morphological, mechanical, thermal, and hydrophilic properties as well as the antimicrobial activity of carboxymethyl chitosan (CMCH) bio-composite films was investigated. The CMCH was synthesized from shrimp chitosan through carboxymethylation, whereas the CaO was synthesized via a co-precipitation method with polyethylene glycol as a stabilizer. The CMCH-CaO bio-composite films were prepared by the addition of synthesized CaO into the synthesized CMCH using a facile solution casting method. As confirmed by XRD and SEM, the synthesized CaO has a cubic shape, with an average crystalline size of 25.84 nm. The synthesized CaO exhibited excellent antimicrobial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (>99.9% R). The addition of CaO into CMCH improved the mechanical and hydrophobic properties of the CMCH-CaO films. However, it resulted in a slight decrease in thermal stability. Notably, the CMCH-CaO10% films exhibited exceptional antimicrobial activity against E. coli (98.8% R) and S. aureus (91.8% R). As a result, such bio-composite films can be applied as an active packaging material for fruit, vegetable, or meat products.

Emerging trends and challenges in polysaccharide derived materials for wound care applications: A review

Polysaccharides are favourable and promising biopolymers for wound care applications due to their abundant natural availability, low cost and excellent biocompatibility. They possess different functional groups, such as carboxylic, hydroxyl and amino, and can easily be modified to obtain the desirable properties and various forms. This review systematically analyses the recent progress in polysaccharides derived materials for wound care applications, emphasizing the most commonly used cellulose, chitosan, alginate, starch, dextran and hyaluronic acid derived materials. The distinctive attributes of each polysaccharide derived wound care material are discussed in detail, along with their different forms, i.e., films, membranes, sponges, nanoemulsions, nanofibers, scaffolds, nanocomposites and hydrogels. The processing methods to develop polysaccharides derived wound care materials are also summarized. In the end, challenges related to polysaccharides derived materials in wound care management are listed, and suggestions are given to expand their utilization in the future to compete with conventional wound healing materials.

Incorporating bioactive glass nanoparticles in silk fibroin/bacterial nanocellulose composite scaffolds improves their biological and osteogenic properties for bone tissue engineering applications

Blend polymers composed of natural polymers are a ubiquitous biomaterial class due to their suitable mechanical and biological characterization. In the present study, composite scaffolds based on bacterial cellulose (BC)/silk fibroin (SF) with bioactive glass nanoparticles (BGNPs) were developed to enhance osteogenesis in human adipose derived stem cells (hASCs). The scanning electron microscopy (SEM) results of BGNPs indicated a spherical morphology and size ranging from 15 to 30 nm. The presence of BC and BGNPs reduced the pore diameter of SF scaffolds to about 210 ± 10 μm and 205 ± 10 μm, respectively, while increasing their compressive strength and compressive modulus. FTIR analyses proved the presence of BGNPs, BC and SF in the scaffolds. Flow cytometry data confirmed the surface markers for hASCs. The results also showed that BC and BGNPs addition to BC/SF scaffolds decreased degradation and swelling rate. The gene expression (Runx2, alkaline phosphatase and osteocalcin) studies signified the osteogenic potential of BGNPs in BC/SF scaffolds on hASCs. Eventually, the increased cell adhesion, viability and differentiation in the BC/SF and BC/SF/BGNPs composite scaffolds drawn from MTT, SEM, Alizarin red staining and alkaline phosphatase activity confirmed that these scaffolds promise to serve as a therapeutic candidate for bone defects.

Vanillin/fungal-derived carboxy methyl chitosan/polyvinyl alcohol hydrogels prepared by freeze-thawing for wound dressing applications

In this study, we developed hydrogels using polyvinyl alcohol (PVA), vanillin (V), and a fungus-derived carboxymethyl chitosan (FC) using a freeze-thaw-based method. These hydrogels were strengthened by bonding, including Schiff's base bonding between V and FC and hydrogen bonding between PVA, FC, and V. The physiological properties of these PFCV hydrogels were characterized by FTIR, TGA, compressive mechanical testing, and rheology and water contact angle measurements. FTIR spectra confirmed the effective integration of FC and V into the PVA network. TGA results showed that FC and V enhanced the thermal stability of PFCV hydrogels. Mechanical tests showed increasing the amount of V reduced mechanical properties but did not alter the elastic character of hydrogels. SEM images displayed a well-interconnected porous structure with excellent swelling capacity. In addition, we examined biological properties using cell-based in vitro studies and performed antibacterial assessments to assess suitability for potential wound dressing applications. Prestoblue™ and live/dead cell analysis strongly supported skin fibroblast attachment and viability, DPPH assays indicated substantial antioxidant activity, and PFCV hydrogels showed enhanced antibacterial effects against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). In summary, incorporating V and FC into PVA hydrogels appears to be attractive for wound dressing applications.

Curdlan/sodium carboxymethylcellulose composite adsorbents: A biodegradable solution for organic dye removal from water

Composite adsorbent comprised of curdlan (CURD) and sodium carboxymethylcellulose (CMC) were fabricated through a single-step heating process, targeting the removal of methylene blue (MB) from wastewater. The CURD/CMC composite adsorbents had a honeycomb porous structure. The integration of CMC not only increased the storage modulus of the CURD/CMC composite hydrogels but also affected the thermal stability and swelling behavior of the composite adsorbents in different pH solutions. Specifically, the addition of 1.2 % CMC increased the peak temperature (184.73 °C) of CURD/CMC composite adsorbent melting by 5.99 °C compared to CURD adsorbent. The addition of CMC improved the swelling ratio of the composite adsorbent at pH 3,7, and 12 with swelling ratio up to 918.07 %. The synergistic interaction between CURD and CMC led to an enhanced adsorption capacity of the aerogel for MB, achieving a maximum adsorption capability of 385.85 mg/g. Adsorption isotherm assessments further demonstrated that the Langmuir isotherm model well fitted the adsorption data of the composite adsorbent on MB. Collectively, these findings underscore the potential of the developed biodegradable adsorbents as promising adsorbents for efficiently eliminating organic dyes from water.

Bone-like apatite formation in biocompatible phosphate-crosslinked bacterial cellulose-based hydrogels for bone tissue engineering applications

Addressing major bone injuries is a challenge in bone regeneration, necessitating innovative 3D hydrogel-based therapeutic approaches to enhance scaffold properties for better bioactivity. Bacterial cellulose (BC) is an excellent scaffold for bone tissue engineering due to its biocompatibility, high porosity, substantial surface area, and remarkable mechanical strength. However, its practical application is limited due to a lack of inherent osteogenic activity and biomineralization ability. In this study, we synthesized bone-like apatite in biocompatible BC hydrogel by introducing phosphate groups. Hydrogels were prepared using fibrous BC, acrylamide (AM), and bis [2-methacryloyloxy] ethyl phosphate (BMEP) as a crosslinker through free radical polymerization (P-BC-PAM). P-BC-PAM hydrogels exhibited outstanding compressive mechanical properties, highly interconnected porous structures, good swelling, and biodegradable properties. BMEP content significantly influenced the physicochemical and biological properties of the hydrogels. Increasing BMEP content enhanced the fibrous structure, porosity from 85.1 % to 89.5 %, and compressive mechanical strength. The optimized hydrogel (2.0P-BC-PAM) displayed maximum compressive stress, toughness, and elastic modulus at 75 % strain: 221 ± 0.08 kPa, 24,674.2 ± 978 kPa, and 11 ± 0.47 kPa, respectively. P-BC-PAM hydrogels underwent biomineralization in simulated body fluid (SBF) for 14 days, forming bone-like apatite with a Ca/P ratio of 1.75, similar to hydroxyapatite. Confirmed by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM), this suggests their potential as scaffolds for bone tissue engineering. MC3T3-E1 osteoblast cells effectively attached and proliferated on P-BC-PAM. In summary, this study contributes insights into developing phosphate-functionalized BC-based hydrogels with potential applications in bone tissue engineering.

A photocrosslinked methacrylated carboxymethyl chitosan/oxidized locust bean gum double network hydrogel for cartilage repair

Repairing articular cartilage defects is a great challenge due to the poor self-regenerative capability of cartilage. Inspired by active substances found in the natural cartilage extracellular matrix, we used methacrylated carboxymethyl chitosan (MA-CMCS) and oxidized locust bean gum (OLBG) as the hydrogel backbone, and prepared a photocrosslinked dual network hydrogel containing allicin and decellularized cartilage powder (DCP). The rheological, swelling and water retention capacities of MA-CMCS@OLBG-Allicin/DCP (MCOAC) hydrogels were investigated to confirm the successful preparation of hydrogels suitable for cartilage repair. The MCOAC hydrogels showed good antibacterial ability to kill S. aureus and E. coli and anti-inflammatory properties due to the introduction of allicin. Furthermore, MA-CMCS@OLBG-Allicin/DCP hydrogels presented good cytocompatibility due to the addition of DCP, which could promote chondrocyte proliferation and promote the differentiation of BMSCs to chondrocytes. Further studies in vivo demonstrated that the DCP-contained MCOAC hydrogel exhibited superior performance in promoting cartilage tissue growth and wound healing in articular cartilage defects. Thus, the MCOAC hydrogel is a promising cartilage repair hydrogel with potential for clinical use.

Wound Gel with Antimicrobial Effects Based on Polyvinyl Alcohol and Functional Aryloxycyclotriphosphazene

A silver-containing gel based on polyvinyl alcohol and aryloxycyclotriphosphazene containing β-carboxyethenylphenoxy and p-formylphenoxy groups has been developed. Phosphazene was synthesized via the Doebner reaction from hexakis[(4-formyl)phenoxy]cyclotriphosphazene and malonic acid and characterized by ¹H, ¹³C, and ³¹P NMR spectroscopy and MALDI-TOF mass spectrometry. The study of the gel using scanning electron microscopy showed that the gel contains open pores and can absorb wound exudate. The maximum water absorption capacity of the gel was 272%, which was reached after 80 min of testing. The antimicrobial activity of the obtained silver-containing gel was evaluated using the diffusion method. The gel was found to inhibit the growth of the main microorganisms in contact with the skin: the bacteria S. aureus, P. aeruginosa, E. coli, B. subtilis, S. epidermidis, and C. stationis and the fungus C. albicans. The study of the wound-healing effect of the gel in vivo showed a decrease in the wound area of the rabbit hind limb by 91.43% (p < 0.05) on the 10th day of observation and a decrease in the content of C-reactive protein in the rabbit blood serum by 1.3 times (p < 0.05).

Diversity of Bioinspired Hydrogels: From Structure to Applications

Hydrogels are three-dimensional networks with a variety of structures and functions that have a remarkable ability to absorb huge amounts of water or biological fluids. They can incorporate active compounds and release them in a controlled manner. Hydrogels can also be designed to be sensitive to external stimuli: temperature, pH, ionic strength, electrical or magnetic stimuli, specific molecules, etc. Alternative methods for the development of various hydrogels have been outlined in the literature over time. Some hydrogels are toxic and therefore are avoided when obtaining biomaterials, pharmaceuticals, or therapeutic products. Nature is a permanent source of inspiration for new structures and new functionalities of more and more competitive materials. Natural compounds present a series of physico-chemical and biological characteristics suitable for biomaterials, such as biocompatibility, antimicrobial properties, biodegradability, and nontoxicity. Thus, they can generate microenvironments comparable to the intracellular or extracellular matrices in the human body. This paper discusses the main advantages of the presence of biomolecules (polysaccharides, proteins, and polypeptides) in hydrogels. Structural aspects induced by natural compounds and their specific properties are emphasized. The most suitable applications will be highlighted, including drug delivery, self-healing materials for regenerative medicine, cell culture, wound dressings, 3D bioprinting, foods, etc.