A phellinus igniarius polysaccharide/chitosan-arginine hydrogel for promoting diabetic wound healing

A comprehensive review on recent progress in chitosan composite gels for biomedical uses

Chitosan (CS) composite gels have emerged as promising materials with diverse applications in biomedicine. This review provides a concise overview of recent advancements and key aspects in the development of CS composite gels. The unique properties of CS, such as biocompatibility, biodegradability, and antimicrobial activity, make it an attractive candidate for gel-based composites. Incorporating various additives, such as nanoparticles, polymers, and bioactive compounds, enhances the mechanical, thermal, and biological and other functional properties of CS gels. This review discusses the fabrication methods employed for CS composite gels, including blending and crosslinking, highlighting their influence on the final properties of the gels. Furthermore, the uses of CS composite gels in tissue engineering, wound healing, drug delivery, and 3D printing highlight their potential to overcome a number of the present issues with drug delivery. The biocompatibility, antimicrobial properties, electroactive, thermosensitive and pH responsive behavior and controlled release capabilities of these gels make them particularly suitable for biomedical applications. In conclusion, CS composite gels represent a versatile class of materials with significant potential for a wide range of applications. Further research and development efforts are necessary to optimize their properties and expand their utility in pharmaceutical and biomedical fields.

Dopamine-grafted oxidized hyaluronic acid/gelatin/cordycepin nanofiber membranes modulate the TLR4/NF-kB signaling pathway to promote diabetic wound healing

Due to impaired immune function, diabetic wounds are highly susceptible to the development of excessive inflammatory responses and prolonged recurrent bacterial infections that impede diabetic wound healing. Therefore, it is necessary to design and develop a wound dressing that controls bacterial infection and inhibits excessive inflammatory response. In this study, hyaluronic acid (HA) was modified using dopamine (DA). Subsequently, cordycepin (COR) was loaded into dopamine-modified hyaluronic acid (OHDA)/gelatin (GEL) nanofiber wound dressing by electrostatic spinning technique. The constructed COR/OHDA/GEL nanofiber membrane has good thermal stability, hydrophilicity, and air permeability. In vitro experiments showed that the obtained COR/OHDA/GEL nanofiber membranes had good antimicrobial efficacy (S. aureus: 95.60 ± 0.99 %, E. coli: 71.17 ± 6.87 %), antioxidant activity (>90 %), and biocompatibility. In vivo experiments showed that COR/OHDA/GEL nanofiber membranes could promote wound tissue remodeling, collagen deposition, and granulation tissue regeneration. Western blot experiments showed that COR/OHDA/GEL nanofibrous membranes could inhibit the excessive inflammatory response of wounds through the TLR4/NF-κB signaling pathway. Therefore, COR/OHDA/GEL nanofiber membranes could promote diabetic wound healing by modulating the inflammatory response. The results showed that the designed nanofiber wound dressing is expected to provide a new strategy for treating chronic wounds.

Recent Advances of Chitosan-Based Hydrogels for Skin-Wound Dressings

The management of wound healing represents a significant clinical challenge due to the complicated processes involved. Chitosan has remarkable properties that effectively prevent certain microorganisms from entering the body and positively influence both red blood cell aggregation and platelet adhesion and aggregation in the bloodstream, resulting in a favorable hemostatic outcome. In recent years, chitosan-based hydrogels have been widely used as wound dressings due to their biodegradability, biocompatibility, safety, non-toxicity, bioadhesiveness, and soft texture resembling the extracellular matrix. This article first summarizes an overview of the main chemical modifications of chitosan for wound dressings and then reviews the desired properties of chitosan-based hydrogel dressings. The applications of chitosan-based hydrogels in wound healing, including burn wounds, surgical wounds, infected wounds, and diabetic wounds are then discussed. Finally, future prospects for chitosan-based hydrogels as wound dressings are discussed. It is anticipated that this review will form a basis for the development of a range of chitosan-based hydrogel dressings for clinical treatment.

Multifunctional hydrogel bioscaffolds based on polysaccharide to promote wound healing: A review

Various types of skin wounds pose challenges in terms of healing and susceptibility to infection, which can have a significant impact on physical and mental well-being, and in severe cases, may result in amputation. Conventional wound dressings often fail to provide optimal support for these wounds, thereby impeding the healing process. As a result, there has been considerable interest in the development of multifunctional polymer matrix hydrogel scaffolds for wound healing. This review offers a comprehensive review of the characteristics of polysaccharide-based hydrogel scaffolds, as well as their applications in different types of wounds. Additionally, it evaluates the advantages and disadvantages associated with various types of multifunctional polymer and polysaccharide-based hydrogel scaffolds. The objective is to provide a theoretical foundation for the utilization of multifunctional hydrogel scaffolds in promoting wound healing.

Electrospun fibers based anisotropic silk fibroin film with photodynamic antibacterial therapy for S. aureus infected wound healing

Bacterial infection has been regarded as a life-threatening problem in clinic. In addition to screening of new antibiotics, it is important to develop highly effective antibacterial materials against antibiotic resistance with capacities on modulating chronic inflammation. Herein, aligned Chlorin e6 (Ce6) conjugated silk fibroin electrospun fibers were successfully fabricated on silk fibroin based film via electrospining to achieve effective photodynamic antibacterial activities under near infrared (NIR) irradiation. The aligned electrospun fiber based film composite (SFCF@Film) exhibited good mechanical properties and desirable hemocompatibility. SFCF@Film provided a promising guidance cue for directing cell orientation and promoting cell growth. Significantly, SFCF@Film effectively generated ROS under NIR irradiation to kill S. aureus for treating wound infections within 10 min and promoted M2 polarization of macrophages for wound healing at later stage. Therefore, we believed that this engineered bioscaffold can be a powerful strategy for handling wound infection.

"Sandwich-like" structure electrostatic spun micro/nanofiber polylactic acid-polyvinyl alcohol-polylactic acid film dressing with metformin hydrochloride and puerarin for enhanced diabetic wound healing

A diabetic wound is a typical chronic wound with a long repair process and poor healing effects. It is an effective way to promote diabetic wound healing to design electrospinning nanofiber films with drug-assisted therapy, good air permeability and, a multilayer functional structure. In this paper, a diabetic wound dressing with a "sandwich-like" structure was designed. Metformin hydrochloride, loaded in the hydrophilic PVA inner layer, could effectively promote diabetic wound healing. The drug release was slowed down by osmosis. The laminate film dressing had good mechanical properties, with tensile strength and elongation at break reaching 5.91 MPa and 90.47 %, respectively, which was close to human skin. The laminate film loaded with erythromycin and puerarin in the hydrophobic PLA outer layer had good antibacterial properties. In addition, due to the high specific surface of the electrostatic spun film, it exhibited high water vapor permeability. It facilitates the gas exchange between the wound and the outside world. The cell experiments proved that the laminate film dressing had good biocompatibility. There was no toxic side effect on cell proliferation. In the diabetic animal wound model, it was shown that the closure rate of diabetic wound repair by laminate film reached 91.11 % in the second week. Our results suggest that the "sandwich-like" nanofiber film dressing could effectively promote the healing process and meet the various requirements of diabetic wound dressing as a promising candidate for future clinical application of chronic wound dressings.

Injectable thermogel incorporating reactive oxygen species scavenger and nitric oxide donor to accelerate the healing process of diabetic wounds

The healing of diabetic wounds is challenging due to redox imbalances. Herein, the thermogelling system AR-ACP hydrogel, with encapsulated biosafe nitric oxide (NO) donor L-arginine and resveratrol as an ROS scavenger, is established for sustainable wound therapy in the diabetic state. The innovated AR-ACP hydrogel dressings shows the sol-gel transition at 34 °C, allowing the hydrogel to fully cover wounds. The combination of L-arginine and resveratrol showed a prominent effect on anti-oxidative activity. The elimination of superoxide anions from the activated immune cells/oxidative cells by resveratrol maintained the NO-proangiogenic factors generated from L-arginine. Furthermore, the AR-ACP hydrogel endowed outstanding features such as haemocompatibility, non-skin irradiation as well as antibacterial activity. In the in vivo diabetic mice model, complete epidermal regeneration comparable to undamaged skin was observed with AR-ACP hydrogel. The synergy between L-arginine and resveratrol in the ACP hydrogel facilitated neovascularisation in the early stage, resulting in the higher balance in cellularity growth and collagen deposition in the dermal layer compared to control groups. Taken together, our findings demonstrate that the use of a customised ACP-based hydrogel, with the additional L-arginine and resveratrol, resulted in significant skin regeneration in the diabetic state.