A novel antibacterial hydrogel based on thiolated ovalbumin/gelatin with silver ions to promote wound healing in mice

An Antibacterial Hydrogel Based on Silk Sericin Cross-Linking Glycyrrhizic Acid and Silver for Infectious Wound Healing

Bioactive hydrogels are garnering increasing interest in wound management due to their porous structural features and versatile intrinsic biological activities. Importantly, the antibacterial capacity is a crucial requirement for hydrogel dressings in chronically infected wounds. In this study, we report an antibacterial hydrogel constructed from silk sericin (SS) cross-linked with glycyrrhizic acid (GA) and integrated with silver ions (Ag+) to accelerate the healing of bacterial-infected wounds. The resultant sericin-glycyrrhizic acid-Ag+ hydrogel (SGA) demonstrates favorable mechanical properties, effectively preventing secondary injury to wounds. Moreover, in vitro studies indicated that the SGA hydrogel possesses excellent swelling ratios, degradability, and cytocompatibility, promoting cell growth and proliferation. Notably, the SGA hydrogel exhibited effective antibacterial activity against both Gram-positive and Gram-negative bacteria through the release of Ag+. In a Staphylococcus aureus-infected wound model, the SGA hydrogel efficiently eradicated bacteria, thus promoting wound repair. Overall, our work establishes a novel strategy for developing multifunctional hydrogel dressings based on natural materials for managing bacteria-infected wounds.

Silver nanoparticle-loaded konjac glucomannan/silk fibroin composite hydrogels for enhanced wound healing

Hydrogel dressings with good biocompatibility and extracellular matrix mimetic structure are important for the treatment of skin wounds. In this study, antimicrobial silver nanoparticles (Ag NPs) loaded with konjac glucomannan and silk fibroin (KGM/SF) composite hydrogel were used as a dressing for wound healing. The uniform distribution of Ag NPs on the surface of the hydrogels imparts excellent antibacterial properties to KGM/SF composite hydrogels. Furthermore, the incorporation of Ag NPs into KGM/SF composite hydrogels does not induce significant hemolysis, there by meeting the standards for wound dressings and exhibiting favorable biocompatibility. In addition, the SF distribution of complex hydrogel dressings is rich in amino groups, thus providing excellent biocompatibility and comfort. The KGM/SF composite hydrogels possess a porous network structure, which endows them with excellent water retention and the capability to absorb wound exudate. Additionally, this unique structure creates and maintains an optimal moist environment that facilitates wound healing. The KGM/SF composite hydrogel dressing loaded with Ag NPs exhibits excellent hemostatic ability in the skin defect model, thereby facilitating angiogenesis, granulation tissue formation, and collagen accumulation to effectively promote wound healing.

Double cross-linked cellulose hydrogel-supported Fe species for efficient wound healing

Traditional dressings often lack adequate skin structure support, which can lead to secondary damage, poor hemostasis, and an increased risk of inflammation due to wound adhesion. In this work, cellulose hydrogels were prepared by physical/chemical double cross-linking via a 'sol-gel' strategy and further loaded with Fe to obtain a three-dimensional (3D) porous cellulose/Fe composite hydrogel (cellulose/Fe gel). The obtained cellulose/Fe gel featured a 3D porous nanofiber structure, excellent water absorption/moisture retention performance, and good mechanical stability. Moreover, it could effectively remove reactive oxygen species (ROS) and inhibit cellular oxidative stress, demonstrating potential anti-inflammatory effects. When applied to wound repair in rats, cellulose/Fe gel, with excellent cell compatibility, effectively stimulated the formation of new blood vessels and significantly reduced the level of inflammatory factors, promoting wound healing. This work provides a new approach for cellulose-based hydrogel wound dressings.

A Standardized Mouse Model for Wound Infection with Pseudomonas aeruginosa

Pseudomonas aeruginosa is a highly drug-resistant pathogen known to impair wound healing and provoke inflammatory responses, potentially leading to immune dysregulation. This study aimed to systematically investigate the immune response mechanisms mediated by cytokines following P. aeruginosa infection through the development of a standardized wound model. Kunming mice were selected as experimental subjects and given 8 mm diameter lesions on their backs and inoculated with standard strains PAO1 and PA14. The key parameters assessed included changes in body weight, wound redness and swelling, bacterial dynamics, protein content in wound tissues, immune responses, and pathological alterations. The results demonstrated that pathogen invasion significantly inhibited wound healing, with healing rates in the infected groups (87.5 ± 6.3% and 77.1 ± 3.6%) being notably lower than those in the uninfected control group. P. aeruginosa persisted in the wounds for up to 12 days, with bacterial loads decreasing from 8 log to 2 log. Additionally, there was a marked reduction in the protein content of the wound tissue and an increase in the expression levels of inflammatory factors such as IL-1β and TNF-α. The thickness of granulation tissue and the number of neovessels were significantly lower compared to the uninfected control group. This study establishes a standardized paradigm for creating a mouse model of P. aeruginosa infection in wounds, emphasizing the importance of appropriate mouse strains, uniform wound preparation methods, and moderate inoculation doses for reliable and accurate experimental results. These elements will facilitate the assessment of changes across six key indicators post-infection, providing a foundational data set and technical support for future mechanistic investigations of P. aeruginosa infection and the development of targeted antimicrobial strategies.

Enhanced Mechanical Strength and Sustained Drug Release in Carrier-Free Silver-Coordinated Anthraquinone Natural Antibacterial Anti-Inflammatory Hydrogel for Infectious Wound Healing

The persistent challenge of healing infectious wounds and the rise of bacterial resistance represent significant hurdles in contemporary medicine. In this study, based on the natural small molecule drug Rhein self-assembly to form hydrogels and coordinate assembly with silver ions (Ag+), a sustained-release carrier-free hydrogel with compact structure is constructed to promote the repair of bacterial-infected wounds. As a broad-spectrum antimicrobial agent, Ag+ can avoid the problem of bacterial resistance caused by the abuse of traditional antibiotics. In addition, due to the slow-release properties of Rhein hydrogel, continuous effective concentration of Ag+ at the wound site can be ensured. The assembly of Ag+ and Rhein makes the hydrogel system with enhanced mechanical stability. More importantly, it is found that Rhein effectively promotes skin tissue regeneration and wound healing by reprogramming M1 macrophages into M2 macrophages. Further mechanism studies show that Rhein realizes its powerful anti-inflammatory activity through NRF2/HO-1 activation and NF-κB inhibition. Thus, the hydrogel system combines the excellent antibacterial properties of Ag+ with the excellent anti-inflammatory and tissue regeneration ability of Rhein, providing a new strategy for wound management with dual roles.

A Novel Food Bore Protein Hydrogel with Silver Ions for Promoting Burn Wound Healing

Hydrogels have emerged as a promising option for treating local scald wounds due to their unique physical and chemical properties. This study aims to evaluate the efficacy of ovalbumin/gelatin composite hydrogels in repairing deep II-degree scald wounds using a mouse dorsal skin model. Trauma tissues collected at various time points are analyzed for total protein content, hydroxyproline content, histological features, and expression of relevant markers. The results reveal that the hydrogel accelerates the healing process of scalded wounds, which is 17.27% higher than the control group. The hydrogel treatment also effectively prevents wound enlargement and redness of the edges caused by infection during the initial stage of scalding. The total protein and hydroxyproline content of the treated wounds are significantly elevated. Additionally, the hydrogel up-regulates the expression of VEGF (a crucial angiogenic factor) and down-regulates CD68 (a macrophage marker). In summary, this study provides valuable insights into the potential of multifunctional protein-based hydrogels in wound healing.

Natural blackcurrant extract contained gelatin hydrogel with photothermal and antioxidant properties for infected burn wound healing

Burns represent a prevalent global health concern and are particularly susceptible to bacterial infections. Severe infections may lead to serious complications, posing a life-threatening risk. Near-infrared (NIR)-assisted photothermal antibacterial combined with antioxidant hydrogel has shown significant potential in the healing of infected wounds. However, existing photothermal agents are typically metal-based, complicated to synthesize, or pose biosafety hazards. In this study, we utilized plant-derived blackcurrant extract (B) as a natural source for both photothermal and antioxidant properties. By incorporating B into a G-O hydrogel crosslinked through Schiff base reaction between gelatin (G) and oxidized pullulan (O), the resulting G-O-B hydrogel exhibited good injectability and biocompatibility along with robust photothermal and antioxidant activities. Upon NIR irradiation, the controlled temperature (around 45-50 °C) generated by the G-O-B hydrogel resulted in rapid (10 min) and efficient killing of Staphylococcus aureus (99 %), Escherichia coli (98 %), and Pseudomonas aeruginosa (82 %). Furthermore, the G-O-B0.5 hydrogel containing 0.5 % blackcurrant extract promoted collagen deposition, angiogenesis, and accelerated burn wound closure conclusively, demonstrating that this well-designed and extract-contained hydrogel dressing holds immense potential for enhancing the healing process of bacterial-infected burn wounds.