In situ photo-crosslinking silk fibroin based hydrogel accelerates diabetic wound healing through antibacterial and antioxidant

NIR-responsive injectable nanocomposite hydrogels with enhanced angiogenesis for promoting full-thickness wound healing

Angiogenesis plays a vital role in the treatment of full-thickness wounds. Deferoxamine (DFO) has been employed to promote neovascularization, however, smart drug delivery systems are needed to optimize its utilization. In this study, an injectable extracellular matrix (ECM)-mimicking hydrogel (HOG@P&D) was developed by leveraging the dynamic Schiff base and hydrogen bonds among a chitosan derivative (HACC), oxidized alginate (OSA), gelatin, and DFO-loaded polydopamine nanoparticles (P&D) for efficient wound healing. The incorporation of P&D enables HOG@P&D to respond to near-infrared (NIR) irradiation, converting laser energy into heat to trigger an on-demand, rapid release of DFO, thereby effectively enhancing angiogenesis. In vitro tube formation assays revealed that the number of meshes in the HOG@P&D group was fourfold higher than that of the control group. Additionally, HOG@P&D exhibited superior mechanical properties, tissue adhesion, and injectability, allowing it to cover wounds seamlessly. This hydrogel also demonstrated antibacterial and antioxidant properties, creating a conducive microenvironment for wound healing. In vivo studies further confirmed that HOG@P&D promoted angiogenesis and mitigated inflammation by upregulating angiogenic growth factor expression, thereby accelerating full-thickness wound healing. This nanocomposite hydrogel shows significant potential as a high-performance wound dressing.

Silkworm cocoon bionic design in wound dressings: A novel hydrogel with self-healing and antimicrobial properties

Hydrogels with rapid wound-healing capabilities and antimicrobial effects are gaining significant interest in related fields. Nonetheless, developing a multifunctional hydrogel wound dressing with injectable self-assembling, self-healing, antimicrobial properties, and efficient skin wound-healing capabilities remained a formidable challenge. In this experiment, we drew inspiration from silkworm cocoons' natural formation and protective mechanisms, employing a novel physical cross-linking method to create an injectable and self-healing quaternary hydrogel successfully. The hydrogel is based on a matrix of silk fibroin/silk sericin (SF/SS), with 1,2-dimyristoyl-sn-glycero-3-phosphate sodium salt (DMPG) serving as a physical cross-linking agent to form the hydrogel network structure, and the incorporation of silver nanoparticles (AgNPs) further enhances its antimicrobial capabilities. Our biomimetic hydrogel, which replicated the chemical properties of silkworm cocoons, demonstrated excellent hydrophilicity with a water contact angle that ranged from 37 to 52°. Its tensile and compressive resistance was approximately four times greater than that of a pure SF hydrogel, and its swelling performance was about three times higher than that of a pure SF hydrogel. Furthermore, the hydrogel exhibited an impressive bacterial inhibition rate of over 98 % in bacterial growth and inhibition experiments, which provided a solid foundation for accelerating wound healing. Likewise, experiments with mice and histological analyses revealed that on day 7, the expression of TNF-α and IL-1β in the wound tissues treated with the SF/SS/AgNPs hydrogel was significantly reduced by >25 % compared to the blank control group. This reduction indicates that the hydrogel could decrease the production of inflammatory cytokines, potentially aiding in the acceleration of wound healing and mitigation of inflammation-related adverse reactions. By day 14, the wounds were healed mainly, with the wound area reduced by 17 % compared to that of the blank group. This demonstrates the significant potential of this cocoon-mimetic hydrogel in accelerating wound healing and providing wound protection.

Using Hybrid MnO2-Au Nanoflowers to Accelerate ROS Scavenging and Wound Healing in Diabetes

Objectives: Excessive reactive oxygen species (ROS) in diabetic wounds are major contributors to chronic wounds and impaired healing, posing significant challenges in regenerative medicine. Developing innovative drug delivery systems is crucial to address these issues by modifying the adverse microenvironment and promoting effective wound healing. Methods: Herein, we designed a novel drug delivery platform using manganese dioxide nanoflower hybridized gold nanoparticle composites (MnO2-Au) synthesized via a hydrothermal reaction, and investigated the potential of MnO2-Au nanoflowers to relieve the high oxidative stress microenvironment and regulate diabetic wound tissue healing. Results: This hybrid material demonstrated superior catalytic activity compared to MnO2 alone, enabling the rapid decomposition of hydrogen peroxide and a substantial reduction in ROS levels within dermal fibroblasts. The MnO2-Au nanoflowers also facilitated enhanced dermal fibroblast migration and Col-I expression, which are critical for tissue regeneration. Additionally, a hydrogel-based wound dressing incorporating MnO2-Au nanoflowers was developed, showing its potential as an intelligent drug delivery system. This dressing significantly reduced oxidative stress, accelerated wound closure, and improved the quality of neonatal epithelial tissue regeneration in a diabetic rat skin defect model. Conclusions: Our findings underscore the potential of MnO2-Au nanoflower-based drug delivery systems as a promising therapeutic approach for chronic wound healing, particularly in regenerative medicine.

A poly (lactic-co-glycolic acid) self-pumping Janus dressing with bidirectional biofluid transport for diabetic wound healing via anti-bacteria and pro-angiogenesis

Diabetic wound healing poses a substantial challenge owing to bacterial infections, insufficient angiogenesis, and excessive exudates. Currently, most of the clinical dressings used for diabetic wounds are still conventional dressings such as gauze. In this study, a three-layer Janus dressing was developed via continuous electrostatic spinning. The top-layer was composed of polylactic acid-glycolic acid and hydroxyapatite doped with silver ions and silicate. The hydrophobic top-layer prevented the adhesion of foreign bacteria. The mid-layer was composed of polyethylene glycol, polylactic acid-glycolic acid and hydroxyapatite doped with silver ions and silicate facilitated exudate absorption and bioactive ion release. The modified sub-layer containing polylactic acid-glycolic acid, hydroxyapatite doped with silver ions and silicate and sodium alginate microspheres enabled both the transport of wound exudate from the wound bed to dressing and the backflow of bioactive silver ions and silicate to the wound bed, thereby reducing infection and stimulating angiogenesis. Through in vivo and in vivo experiments, the Janus dressing showed to have antimicrobial, angiogenic, and exudate-control properties that accelerate healing in diabetic wounds. As a novel dressing, the multifunctional, self-pumping Janus wound dressing with bi-directional biofluidic transport offers a new approach to diabetic wound healing.

A comprehensive exploration of hydrogel applications in multi-stage skin wound healing

Hydrogels, as an emerging biomaterial, have found extensive use in the healing of wounds due to their distinctive physicochemical structure and functional properties. Moreover, hydrogels can be made to match a range of therapeutic requirements for materials used in wound healing through specific functional modifications. This review provides a step-by-step explanation of the processes involved in cutaneous wound healing, including hemostasis, inflammation, proliferation, and reconstitution, along with an investigation of the factors that impact these processes. Furthermore, a thorough analysis is conducted on the various stages of the wound healing process at which functional hydrogels are implemented, including hemostasis, anti-infection measures, encouraging regeneration, scar reduction, and wound monitoring. Next, the latest progress of multifunctional hydrogels for wound healing and the methods to achieve these functions are discussed in depth and categorized for elucidation. Finally, perspectives and challenges associated with the clinical applications of multifunctional hydrogels are discussed.

Multifunctional polypeptide-based hydrogel bio-adhesives with pro-healing activities and their working principles

Wound healing is a complex physiological process involving hemostasis, inflammation, proliferation, and tissue remodeling. Therefore, there is an urgent need for suitable wound dressings for effective and systematical wound management. Polypeptide-based hydrogel bio-adhesives offer unique advantages and are ideal candidates. However, comprehensive reviews on polypeptide-based hydrogel bio-adhesives for wound healing are still lacking. In this review, the physiological mechanisms and evaluation parameters of wound healing were first described in detail. Then, the working principles of hydrogel bio-adhesives were summarized. Recent advances made in multifunctional polypeptide-based hydrogel bio-adhesives involving gelatin, silk fibroin, fibrin, keratin, poly-γ-glutamic acid, ɛ-poly-lysine, serum albumin, and elastin with pro-healing activities in wound healing and tissue repair were reviewed. Finally, the current status, challenges, developments, and future trends of polypeptide-based hydrogel bio-adhesives were discussed, hoping that further developments would be stimulated to meet the growing needs of their clinical applications.

Hydrogels in Cutaneous Wound Healing: Insights into Characterization, Properties, Formulation and Therapeutic Potential

Hydrogels are polymeric materials that possess a set of characteristics meeting various requirements of an ideal wound dressing, making them promising for wound care. These features include, among others, the ability to absorb and retain large amounts of water and the capacity to closely mimic native structures, such as the extracellular matrix, facilitating various cellular processes like proliferation and differentiation. The polymers used in hydrogel formulations exhibit a broad spectrum of properties, allowing them to be classified into two main categories: natural polymers like collagen and chitosan, and synthetic polymers such as polyurethane and polyethylene glycol. This review offers a comprehensive overview and critical analysis of the key polymers that can constitute hydrogels, beginning with a brief contextualization of the polymers. It delves into their function, origin, and chemical structure, highlighting key sources of extraction and obtaining. Additionally, this review encompasses the main intrinsic properties of these polymers and their roles in the wound healing process, accompanied, whenever available, by explanations of the underlying mechanisms of action. It also addresses limitations and describes some studies on the effectiveness of isolated polymers in promoting skin regeneration and wound healing. Subsequently, we briefly discuss some application strategies of hydrogels derived from their intrinsic potential to promote the wound healing process. This can be achieved due to their role in the stimulation of angiogenesis, for example, or through the incorporation of substances like growth factors or drugs, such as antimicrobials, imparting new properties to the hydrogels. In addition to substance incorporation, the potential of hydrogels is also related to their ability to serve as a three-dimensional matrix for cell culture, whether it involves loading cells into the hydrogel or recruiting cells to the wound site, where they proliferate on the scaffold to form new tissue. The latter strategy presupposes the incorporation of biosensors into the hydrogel for real-time monitoring of wound conditions, such as temperature and pH. Future prospects are then ultimately addressed. As far as we are aware, this manuscript represents the first comprehensive approach that brings together and critically analyzes fundamental aspects of both natural and synthetic polymers constituting hydrogels in the context of cutaneous wound healing. It will serve as a foundational point for future studies, aiming to contribute to the development of an effective and environmentally friendly dressing for wounds.

Recent advances of hydrogels as smart dressings for diabetic wounds

Chronic diabetic wounds have been an urgent clinical problem, and wound dressings play an important role in their management. Due to the design of traditional dressings, it is difficult to achieve adaptive adhesion and on-demand removal of complex diabetic wounds, real-time monitoring of wound status, and dynamic adjustment of drug release behavior according to the wound microenvironment. Smart hydrogels, as smart dressings, can respond to environmental stimuli and achieve more precise local treatment. Here, we review the latest progress of smart hydrogels in wound bandaging, dynamic monitoring, and drug delivery for treatment of diabetic wounds. It is worth noting that we have summarized the most important properties of smart hydrogels for diabetic wound healing. In addition, we discuss the unresolved challenges and future prospects in this field. We hope that this review will contribute to furthering progress on smart hydrogels as improved dressing for diabetic wound healing and practical clinical application.

"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.