Tuning the properties of carboxymethylchitosan-based porous membranes for potential application as wound dressing

Characterization of sustainable biocompatible materials based on chitosan: cellulose composites containing sporopollenin exine capsules

In this work, photothermal beam deflection spectrometric technique (BDS) is applied for non-contact and non-destructive characterization of chitosan (CS): cellulose (CEL) biocomposites with incorporated sporopollenin exine capsules (SEC). The objective was to determine the structural and thermal properties of synthesized CS:CEL:SEC composites with varying amounts of SEC, and to validate the BDS by photopyroelectric calorimetry (PPE) as an independent technique. It was found that CS:CEL biocomposites without SEC exhibit low porosities, which are on the order of 0.005 %, but can be increased by augmenting the content of CEL in the composite and/or by incorporation of SEC. By increasing the SEC content of CS:CEL composites to 50 % (w/w), the porosity increased up to 0.17 %. SEC also increases the surface roughness of biocomposite by over 2000-times to reach the roughness amplitude of 6 μm in composites with 50 % SEC. The thermal conductivities of investigated biocomposites were in the range of 40-80 mWm-1 K-1, while the thermal diffusivities were on the order of fractions of mm2s-1. With first validation of BDS results for thermal properties of CS:CEL-based composites, which show agreement with PPE results to within 5 %, this study confirms BDS technique as a perspectives tool for non-destructive characterization of CS:CEL:SEC biocomposites.

Clinical Applicable Carboxymethyl Chitosan with Gel-Forming and Stabilizing Properties Based on Terminal Sterilization Methods of Electron Beam Irradiation

Carboxymethyl chitosan (CMC)-based hydrogels have great potential for clinical applications, but a critical sterilization process must be addressed to bring them to market. Compared to ethylene oxide sterilization or heat sterilization, irradiation sterilization avoids alkylation and heat damage, while available studies on γ-irradiated other polysaccharides show that solution polysaccharides are susceptible to degradation or cross-linking. Aiming at the challenges brought by the γ-irradiation process of polysaccharide aqueous solution, this paper innovatively proposes the lyophilized CMC using electron beam (EB) irradiation, which not only avoids the generation of free radicals in the irradiated water leading to the degradation and cross-linking of polysaccharides but also retains the properties of CMC in terms of gel formation, stabilization, and clinical application. We used FTIR, TG, GPC, and microbial load tests to demonstrate that lyophilized CMC did not have significant changes in structure and molecular weight after EB irradiation, complied with the requirements for sterilization, and still had gel stability, thus proving that lyophilized CMC could be used for EB irradiation and met the requirements for clinical application. Therefore, this work is expected to further advance CMC injectable hydrogels toward clinical applications and provide a new direction for the sterilization processes of other polysaccharide hydrogels.

Silver-infused lysine crosslinked hydrogel with oxidized regenerated cellulose for prospective advanced wound dressings

The study aimed to develop a multifunctional wound dressing with enhanced antibacterial properties and wound healing promotion. The synthesis process involved preparing oxidized regenerated cellulose (ORC) following a modified procedure, synthesizing chitosan/silver nanoparticles (CS/Ag NPs) via an in-situ reduction method, and subsequently preparing ORC/CS/Lys@Ag NPs hydrogels. Characterization techniques including FTIR, XRD, SEM, and EDS were employed to analyze functional groups, lattice structure, morphology, and elemental composition. Gelation time, swelling behavior, water retention, mechanical properties, viscosity, self-healing capacity, rheological behavior, oxygen permeability, in vitro degradation, release of Ag+, and antibacterial properties were evaluated using various experimental methods. Results indicated that the novel wound dressing has the capability to evenly distribute Ag NPs to effectively counteract bacteria. It can maintain moist conditions for 86 h, resist a sturdy mechanical pressure of 11.3 KPa, and degrade by 11.045 % ± 0.429 within 8 h. Combining its efficient gas exchange abilities, self-repairing function, and biocompatibility, almost full recovery was observed in injured mouse skin within 13 days, highlighting its promising clinical utility.

A biodegradable oxidized starch/carboxymethyl chitosan film coated with pesticide-loaded ZIF-8 for tomato fusarium wilt control

Film mulching is one of the most important methods to control soil-borne diseases. However, the traditional mulch may cause microplastic pollution and soil ecological damage. Herein, a biodegradable film was developed using oxidized starch and carboxymethyl chitosan and incorporated ZIF-8 carrying fludioxonil to sustainably control soil-borne disease. The microstructure, mechanical properties, optical properties, and water barrier properties of the composite films (Flu@ZIF-8-OS/CMCS) were investigated. The results show that Flu@ZIF-8-OS/CMCS had a smooth and uniform surface and excellent light transmittance. The excellent mechanical properties of the films were verified by tensile strength, elongation at break and Young's modulus. Higher contact angle and lower water vapor permeability indicate water retention capacity of the soil was improved through using Flu@ZIF-8-OS/CMCS. Furthermore, the release properties, biological activity, degradability and safety to soil organisms of Flu@ZIF-8-OS/CMCS was determined. The addition of ZIF-8 significantly improved the film's ability to retard the release of Flu, while the Flu@ZIF-8-OS/CMCS has good soil degradability. In vitro antifungal assays and pot experiments demonstrated excellent inhibitory activity against Fusarium oxysporum f. sp. Lycopersici. Flu@ZIF-8-OS/CMCS caused only 13.33 % mortality of earthworms within 7 d. This research provides a new approach to reducing microplastic pollution and effectively managing soil-borne diseases.

Carboxymethyl chitosan-gelatin-mesoporous silica nanoparticles containing Myrtus communis L. extract as a novel transparent film wound dressing

Wound healing and health care requirements have attracted more attention, and the need to develop new drug-containing dressings to accelerate wound healing is required. Carboxymethyl chitosan (CMCS)/gelatin-based films with mesoporous silica nanoparticles (MSNs) containing the Myrtus communis L. (Myrtle) aqueous extract were designed to answer this demand. Myrtle aqueous extract included total phenolic content and good free radical scavenging ability in vitro assay. The infrared spectroscopy characterized the functional groups of myrtle extract and biocomposite films. It was found that mesoporous silica nanoparticles increased the tensile strength of the flexible dressings, which is essential in therapeutic uses. MSNs influenced swelling ratio, oxygen, and water vapor permeability that indicates the CMCS/Gelatin/Myrtle/5 % MSNs wound dressing can absorb wound exudates and preserve skin moisture. Also, these biocompatible nanoparticles reduced the cytotoxicity of fibroblast cells due to the decelerated drug release. Correspondingly, silica nanoparticles affected the extract release rate and could accumulate and release the extract prolonged in CMCS/Gelatin/Myrtle/5 % MSNs models. Finally, histological analysis showed collagen growth and fibroblast migration in wounds treated with CMCS/Gelatin/Myrtle/5 % MSNs, causing proper wound contraction and accelerating wound healing in mice models. The results suggest that CMCS/Gelatin/Myrtle/5 % MSNs films have a beneficial application as wound dressings.

Multifunctional bilayer membranes composed of poly(lactic acid), beta-chitin whiskers and silver nanoparticles for wound dressing applications

Nanomaterial-based wound dressings have been extensively studied for the treatment of both minor and life-threatening tissue injuries. These wound dressings must possess several crucial characteristics, such as tissue compatibility, non-toxicity, appropriate biodegradability to facilitate wound healing, effective antibacterial activity to prevent infection, and adequate physical and mechanical strength to withstand repetitive dynamic forces that could potentially disrupt the healing process. Nevertheless, the development of nanostructured wound dressings that incorporate various functional micro- and nanomaterials in distinct architectures, each serving specific purposes, presents significant challenges. In this study, we successfully developed a novel multifunctional wound dressing based on poly(lactic acid) (PLA) fibrous membranes produced by solution-blow spinning (SBS) and electrospinning. The PLA-based membranes underwent surface modifications aimed at tailoring their properties for utilization as effective wound dressing platforms. Initially, beta-chitin whiskers were deposited onto the membrane surface through filtration, imparting hydrophilic character. Afterward, silver nanoparticles (AgNPs) were incorporated onto the beta-chitin layer using a spray deposition method, resulting in platforms with antimicrobial properties against both Staphylococcus aureus and Escherichia coli. Cytotoxicity studies demonstrated the biocompatibility of the membranes with the neonatal human dermal fibroblast (HDFn) cell line. Moreover, bilayer membranes exhibited a high surface area and porosity (> 80%), remarkable stability in aqueous media, and favorable mechanical properties, making them promising candidates for application as multifunctional wound dressings.

Production of anti-inflammatory films based on cashew gum polysaccharide and polyvinyl alcohol for wound dressing applications

In the present study, we aimed to produce CGP/PVA films containing entrapped anti-inflammatory drugs for wound dressing applications. Using a 33-1 fractional factorial design, the effect of each component was evaluated on the physicochemical and morphological properties of the produced materials. The best formulation for entrapment of diclofenac sodium and ketoprofen was also determined. The produced films presented high swelling capacity, with some formulations showing o porous structure. CGP/PVA films showed a maximum retention of 75.6% for diclofenac sodium and 32.2% for ketoprofen, and both drugs were released in a controlled manner for up to 7 h. The drug release kinetic was studied, and the data were fitted using a Korsmeyer-Peppas model, which suggested that the release mechanism is controlled by diffusion. These results indicate that CGP/PVA-based matrices have great potential to be used as drug-delivery systems for wound dressing applications, contributing to prolonging the drug's action time and then improving their anti-inflammatory efficacy.

PGS/Gelatin Nanocomposite Electrospun Wound Dressing

Infectious diabetic wounds can result in severe injuries or even death. Biocompatible wound dressings offer one of the best ways to treat these wounds, but creating a dressing with a suitable hydrophilicity and biodegradation rate can be challenging. To address this issue, we used the electrospinning method to create a wound dressing composed of poly(glycerol sebacate) (PGS) and gelatin (Gel). We dissolved the PGS and Gel in acetic acid (75 v/v%) and added EDC/NHS solution as a crosslinking agent. Our measurements revealed that the scaffolds' fiber diameter ranged from 180.2 to 370.6 nm, and all the scaffolds had porosity percentages above 70%, making them suitable for wound healing applications. Additionally, we observed a significant decrease (p < 0.05) in the contact angle from 110.8° ± 4.3° for PGS to 54.9° ± 2.1° for PGS/Gel scaffolds, indicating an improvement in hydrophilicity of the blend scaffold. Furthermore, our cell viability evaluations demonstrated a significant increase (p < 0.05) in cultured cell growth and proliferation on the scaffolds during the culture time. Our findings suggest that the PGS/Gel scaffold has potential for wound healing applications.

Root-shaped antibacterial alginate sponges with enhanced hemostasis and osteogenesis for the prevention of dry socket

Tooth extraction commonly causes uncontrolled bleeding, loss of blood clots, and bacterial infection, leading to the dry socket and bone resorption. Thus, it is highly attractive to design a bio-multifunctional scaffold with outstanding antimicrobial, hemostatic, and osteogenic performances for avoiding dry sockets in clinical applications. Herein, alginate (AG)/quaternized chitosan (Qch)/diatomite (Di) sponges were fabricated via electrostatic interaction, Ca²⁺ cross-linking, as well as lyophilization methods. The composite sponges are facilely made into the shape of the tooth root, which could be well integrated into the alveolar fossa. The sponge shows a highly interconnected and hierarchical porous structure at the macro/micro/nano levels. The prepared sponges also possess enhanced hemostatic and antibacterial abilities. Moreover, in vitro cellular assessment indicates that the developed sponges have favorable cytocompatibility and significantly facilitate osteogenesis by upregulating the formation of alkaline phosphatase and calcium nodules. The designed bio-multifunctional sponges display great potential for trauma treatment after tooth extraction.

A bionic cellulose nanofiber-based nanocage wound dressing for NIR-triggered multiple synergistic therapy of tumors and infected wounds

Tumor recurrence and drug-resistant bacterial infection are the main reasons that wounds heal with difficulty after skin tumor treatment. The near infrared- (NIR-) and pH-responsive, bionic, cellulose nanofiber-based (CNF-based) nanocage wound dressing with biocompatibility, bioviscosity, and shape adaptability is designed for dual NIR-triggered photothermal therapy of tumor and infection-induced wound healing. The wound dressing with the intertwining three dimensional (3D) nanocage network structure is skillfully constructed using NIR-responsive cellulose nanofibers and pH-responsive cellulose nanofibers as the skeleton, which endows the dressing with a high drug-loading capacity of doxorubicin (400 mg·g^-1), and indocyanine green (25 mg·g^-1). Moreover, the NIR- and pH-responsive bionic "On/Off" switches of the dressing enable a controllable and efficient drug release onto the wound area. The dual NIR-triggered wound dressing with excellent photothermal conversion performance possesses good antibacterial properties against Escherichia coli, Staphylococcus aureus, and drug-resistant Staphylococcus aureus. It could effectively eliminate bacterial biofilms and kill A375 tumor cells. Interestingly, the bionic wound dressing with shape adaptability could adapt and treat irregular postoperative skin tumor wounds and drug-resistant bacterial infection via the synergistic therapy of photothermal, photodynamic, and chemotherapy, which provides an ideal strategy for clinical intervention.

Genipin-cross-linked hydrogels based on biomaterials for drug delivery: a review

Genipin is a naturally occurring nontoxic cross-linker, which has been widely used for drug delivery due to its excellent biocompatibility, admirable biodegradability and stable cross-linked attributes. These advantages led to its extensive application in the fabrication of hydrogels for drug delivery. This review describes the physicochemical characteristics and pharmacological activities of genipin and attempts to elucidate the detailed mechanisms of the cross-linking reaction between genipin and biomaterials. The current article entails a general review of the different biomaterials cross-linked by genipin: chitosan and its derivatives, collagen, gelatin, etc. The genipin-cross-linked hydrogels for various pharmaceutical applications, including ocular drug delivery, buccal drug delivery, oral drug delivery, anti-inflammatory drug delivery, and antibiotic and antifungal drug delivery, are reported. Finally, the future research directions and challenges of genipin-cross-linked hydrogels for pharmaceutical applications are also discussed in this review.