pH-Responsive Injectable Multifunctional Pluronic F127/Gelatin-Based Hydrogels with Hydrogen Production for Treating Diabetic Wounds

A Stable and Local H2 Nanogenerator for Antifading Responses

Persistent inflammation effects existed in the senescence microenvironment, and hydrogen (H2) was an antioxidant stress agent and could solve the aging and inflammation. In view of the issue of low solubility of H2 and conversion efficiency of traditional hydrogen therapy, an in-site hydrogen production system (HPS) was designed by using liposome as a compartment, emodin as a photosensitizer, l-ascorbic acid-2-phosphate trisodium salt (AAP) as hydrogen sources, and Au NPs as photocatalysts. Different from the commonly used chlorophyll A, emodin with strong absorption in the wide range of 200-500 nm could absorb more photons to form electrons for the participation of H2 generation. Emodin- and AAP-embedded HPS largely increased stability at 50 °C for 28 days. HPS facilitated the decrease of inflammatory factors of TNF-α, IL-6, and ROS in RAW264.7 cells, as well as the elimination of senescence-associated β-galactosidase, realizing convenient and efficient antifading responses. But strikingly, the constructed HPS can penetrate the pig skin in transdermal experiments and showed huge prospects for the application of antifading cosmetics.

Material Design, Fabrication Strategies, and the Development of Multifunctional Hydrogel Composites Dressings for Skin Wound Management

The skin is fragile, making it very vulnerable to damage and injury. Untreated skin wounds can pose a serious threat to human health. Three-dimensional polymer network hydrogels have broad application prospects in skin wound dressings due to their unique properties and structure. The therapeutic effect of traditional hydrogels is limited, while multifunctional composite hydrogels show greater potential. Multifunctional hydrogels can regulate wound moisture through formula adjustment. Moreover, hydrogels can be combined with bioactive ingredients to improve their performance in wound healing applications. Stimulus-responsive hydrogels can respond specifically to the wound environment and meet the needs of different wound healing stages. This review summarizes the material types, structure, properties, design considerations, and formulation strategies for multifunctional hydrogel composite dressings used in wound healing. We discuss various types of recently developed hydrogel dressings, highlights the importance of tailoring their physicochemical properties, and addresses potential challenges in preparing multifunctional hydrogel wound dressings.

Probiotic active gel promotes diabetic wound healing through continuous local glucose consumption and antioxidant

BACKGROUND

Diabetic foot ulcers (DFU) are severe complications of diabetes, posing significant health and societal challenges. Accumulation of reactive oxygen species (ROS) and elevated glucose levels are primary factors affecting diabetic wound healing. Achieving effective treatment by reducing ROS alone is challenging, as high glucose levels continuously drive ROS production. The excellent glucose-consuming capacity of lactobacilli and the antioxidant function of hydrogen undoubtedly provide good therapeutic ideas. Herein, we combined probiotic Lactobacillus reuteri with acid-responsive hydrogen-producing nanoparticles to construct probiotic active gel LR&AB@CAH to enable a cascade of glucose consumption and hydrogen production. Lactobacillus reuteri consumed overproduced glucose and thereby released lactic acid to activate nanoparticle for hydrogen production, which could neutralize excess ROS and promote wound healing.

RESULTS

In vitro experiments demonstrate that LR&AB@CAH has good biocompatibility, antioxidant capacity. LR&AB@CAH reduces excess ROS, decreases oxidative substances, and boosts antioxidant enzyme activity. In a diabetic wound mouse model, it functions as a glucose scavenger and antioxidant, reducing ROS and supporting wound healing.

CONCLUSION

LR&AB@CAH offers a novel strategy for the comprehensive treatment of DFU. This study provides an artificial-natural composite hydrogel for cascade therapy on diabetic wound healing, and suggests a complete management approach for diabetic oxidative stress.

Application of Drug Delivery System Based on Nanozyme Cascade Technology in Chronic Wound

Chronic wounds are characterized by long-term inflammation, including diabetic ulcers, traumatic ulcers, etc., which provide an optimal environment for bacterial proliferation. At present, antibiotics are the main clinical treatment method for chronic wound infections. However, the overuse of antibiotics may accelerate the emergence of drug-resistant bacteria, which poses a significant threat to human health. Therefore, there is an urgent need to develop new therapeutic strategies for bacterial infections. Nanozyme-based antimicrobial therapy (NABT) is an emerging antimicrobial strategy with broad-spectrum activity and low drug resistance compared to traditional antibiotics. NABT has shown great potential as an emerging antimicrobial strategy by catalyzing the generation of reactive oxygen species (ROS) with its enzyme-like catalytic properties, producing a powerful bactericidal effect without developing drug resistance. Nanozyme-based cascade antimicrobial technology offers a new approach to infection control, effectively improving antimicrobial efficacy by activating cascades against bacterial cell membranes and intracellular DNA while minimizing potential side effects. However, it is worth noting that this technology is still in the early stages of research. This article comprehensively reviews wound classification, current methods for the treatment of wound infection, different types of nanozymes, the application of nanozyme cascade reaction technology in antimicrobial therapy, and future challenges and prospects.

Endogenous/exogenous stimuli‐responsive smart hydrogels for diabetic wound healing

Diabetes significantly impairs the body's wound‐healing capabilities, leading to chronic, infection‐prone wounds. These wounds are characterized by hyperglycemia, inflammation, hypoxia, variable pH levels, increased matrix metalloproteinase activity, oxidative stress, and bacterial colonization. These complex conditions complicate effective wound management, prompting the development of advanced diabetic wound care strategies that exploit specific wound characteristics such as acidic pH, high glucose levels, and oxidative stress to trigger controlled drug release, thereby enhancing the therapeutic effects of the dressings. Among the solutions, hydrogels emerge as promising due to their stimuli‐responsive nature, making them highly effective for managing these wounds. The latest advancements in mono/multi‐stimuli‐responsive smart hydrogels showcase their superiority and potential as healthcare materials, as highlighted by relevant case studies. However, traditional wound dressings fall short of meeting the nuanced needs of these wounds, such as adjustable adhesion, easy removal, real‐time wound status monitoring, and dynamic drug release adjustment according to the wound's specific conditions. Responsive hydrogels represent a significant leap forward as advanced dressings proficient in sensing and responding to the wound environment, offering a more targeted approach to diabetic wound treatment. This review highlights recent advancements in smart hydrogels for wound dressing, monitoring, and drug delivery, emphasizing their role in improving diabetic wound healing. It addresses ongoing challenges and future directions, aiming to guide their clinical adoption.

Thermoresponsive and Supramolecular Polymers: Interesting Biomaterials for Drug Delivery

How to use and deliver drugs to diseased and damaged areas has been one of the main concerns of pharmacologists and doctors for a long time. With the efforts of researchers, the advancement of technology, and the involvement of engineering in the health field, diverse and promising approaches have been studied and used to achieve this goal. A better understanding of biomaterials and the ability of production equipment led researchers to offer new drug delivery systems to the world. In recent decades, responsive polymers (exclusively to temperature and pH) and supramolecular polymers have received much attention due to their unique capabilities. Although this field of research still needs to be scrutinized and studied more, their recognition, examination, and use as drug delivery systems is a start for a promising future. This review study, focusing on temperature-responsive and supramolecular biomaterials and their application as drug delivery systems, deals with their structure, properties, and role in the noninvasive and effective delivery of medicinal agents.

Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

Stimulus-Responsive Hydrogels for Targeted Cancer Therapy

Cancer is a highly heterogeneous disease and remains a global health challenge affecting millions of human lives worldwide. Despite advancements in conventional treatments like surgery, chemotherapy, and immunotherapy, the rise of multidrug resistance, tumor recurrence, and their severe side effects and the complex nature of the tumor microenvironment (TME) necessitates innovative therapeutic approaches. Recently, stimulus-responsive nanomedicines designed to target TME characteristics (e.g., pH alterations, redox conditions, enzyme secretion) have gained attention for their potential to enhance anticancer efficacy while minimizing the adverse effects of chemotherapeutics/bioactive compounds. Among the various nanocarriers, hydrogels are intriguing due to their high-water content, adjustable mechanical characteristics, and responsiveness to external and internal stimuli, making them promising candidates for cancer therapy. These properties make hydrogels an ideal nanocarrier for controlled drug release within the TME. This review comprehensively surveys the latest advancements in the area of stimulus-responsive hydrogels for cancer therapy, exploring various stimuli-responsive mechanisms, including biological (e.g., pH, redox), chemical (e.g., enzymes, glucose), and physical (e.g., temperature, light), as well as dual- or multi-stimuli responsiveness. Furthermore, this review addresses the current developments and challenges in hydrogels in cancer treatment. Our aim is to provide readers with a comprehensive understanding of stimulus-responsive hydrogels for cancer treatment, offering novel perspectives on their development for cancer therapy and other medical applications.

A Multifunctional, Tough, Stretchable, and Transparent Curcumin Hydrogel with Potent Antimicrobial, Antioxidative, Anti-inflammatory, and Angiogenesis Capabilities for Diabetic Wound Healing

The treatment of diabetic chronic wounds is still faced with great challenges, mainly due to wound infection, excessive inflammation, and peripheral vascular disease in the wound area. Therefore, it is of great importance to develop a novel multifunctional hydrogel with high efficiency to accelerate diabetic wound healing. Curcumin (Cur), a Chinese herbal, has shown great potential in enhancing the healing of diabetic chronic wounds because of its immunomodulatory and pro-angiogenic properties. However, its low aqueous solubility, poor bioavailability, and chemical instability have limited its clinical applications. To address these current bottlenecks, novel poly(vinyl alcohol) (PVA)-chitosan (CS)/sodium alginate (SA)-Cur (PCSA) hydrogels were prepared for the first time, and they demonstrated all of the above intriguing performances by the Michael addition reaction of CS and Cur. PCSA hydrogels show multiple dynamic bonds, which possess strong mechanical properties (tensile stress: ∼0.980 MPa; toughness: ∼258.45 kJ/m3; and compressive strength: ∼7.38 MPa at strain of 80%). These intriguing performances provided an optimal microenvironment for cell migration and proliferation and also promoted the growth of blood vessels, leading to early angiogenesis. Importantly, the experimental results demonstrated that PCSA hydrogels can effectively transform pro-inflammatory M1 macrophages into anti-inflammatory M2 macrophages without the need for additional ingredients in vitro. Benefiting from these characteristics, a full-thickness diabetic wound in a rat model demonstrated that PCSA hydrogels can effectively accelerate wound healing via ROS-scavenging, downregulation of IL-1β, and upregulation of CD31 expression, resulting in angiogenesis and collagen deposition. This strategy not only provides a simple and safe Cur-based hydrogel for diabetic wound healing but also highlights the significant potential for the development of high-performance biomaterials for promoting diabetic wound healing using traditional Chinese medicine.

Microenvironmental dynamics of diabetic wounds and insights for hydrogel-based therapeutics

The rising prevalence of diabetes has underscored concerns surrounding diabetic wounds and their potential to induce disability. The intricate healing mechanisms of diabetic wounds are multifaceted, influenced by ambient microenvironment, including prolonged hyperglycemia, severe infection, inflammation, elevated levels of reactive oxygen species (ROS), ischemia, impaired vascularization, and altered wound physicochemical properties. In recent years, hydrogels have emerged as promising candidates for diabetic wound treatment owing to their exceptional biocompatibility and resemblance to the extracellular matrix (ECM) through a three-dimensional (3D) porous network. This review will first summarize the microenvironment alterations occurring in the diabetic wounds, aiming to provide a comprehensive understanding of its pathogenesis, then a comprehensive classification of recently developed hydrogels will be presented, encompassing properties such as hypoglycemic effects, anti-inflammatory capabilities, antibacterial attributes, ROS scavenging abilities, promotion of angiogenesis, pH responsiveness, and more. The primary objective is to offer a valuable reference for repairing diabetic wounds based on their unique microenvironment. Moreover, this paper outlines potential avenues for future advancements in hydrogel dressings to facilitate and expedite the healing process of diabetic wounds.