Recent advances on the development of wound dressings for diabetic foot ulcer treatment--a review

Endogenous glucose-driven cascade reaction of nano-drug delivery for boosting multidrug-resistant bacteria-infected diabetic wound healing

Multidrug-resistant (MDR) bacteria-infected wound healing remains greatly challenging, especially in diabetic patients. Herein, a novel nano-drug delivery based on endogenous glucose-driven cascade reaction is proposed for boosting MDR bacteria-infected diabetic wound healing with high efficacy by improving wound microenvironment and enhancing photodynamic antibacterial activity. The composite nanoagent is first self-assembled by integrating berberine (BBR) and epigallocatechin gallate (EGCG) from natural plant extracts, named as BENPs, which is successively coated with manganese dioxide nanoshells (MnO2 NSs) and glucose oxidase (GOX) to form the final BEMGNPs. The cascade reaction is triggered by glucose at the wound site of diabetes which is specifically catalyzed by GOX in the BEMGNPs to produce gluconic acid and hydrogen peroxide (H2O2). That is subsequently to decompose MnO2 NSs in the BEMGNPs to generate oxygen (O2). The BEMGNPs as photosensitizers effectively produce reactive oxygen species (ROS) to enhance the eradication of bacteria with the assistance of O2. Under the synergistic function of the cascaded reaction, the BEMGNPs present excellent antibacterial efficacy even for MDR bacteria. The in vivo experiments explicitly validate that the constructed nano-drug delivery can augment the MDR bacteria-infected diabetic wound healing with excellent biosafety. The as-proposed strategy provides an instructive way to combat ever-threatening MDR bacteria, which particularly is beneficial for diabetic patients.

Deep Red Light Driven Hydrogen Evolution by Heterojunction Polymer Dots for Diabetic Wound Healing

We describe small heterojunction polymer dots (Pdots) with deep-red light catalyzed H2 generation for diabetic skin wound healing. The Pdots with donor/acceptor heterojunctions showed remarkably enhanced photocatalytic activity as compared to the donor or acceptor nanoparticles alone. We encapsulate the Pdots and ascorbic acid into liposomes to form Lipo-Pdots nanoreactors, which selectively scavenge ⋅OH radicals in live cells and tissues under 650 nm light illumination. The antioxidant capacity of the heterojunction Pdots is ~10 times higher than that of the single-component Pdots described previously. Under a total light dose of 360 J/cm2, the Lipo-Pdots nanoreactors effectively scavenged ⋅OH radicals and suppressed the expression of pro-inflammatory cytokines in skin tissues, thereby accelerating the healing of skin wounds in diabetic mice. This study provides a feasible solution for safe and effective treatment of diabetic foot ulcers.

Magneto-responsive biocomposites in wound healing: from characteristics to functions

The number of patients with non-healing wounds continuously increases, and has become a prominent societal issue that imposes a heavy burden on both patients and the entire healthcare system. Although traditional dressings play an important role in wound healing, the complexity and diversity of the healing process pose serious challenges in this field. Magneto-responsive biocomposites, with their excellent biocompatibility, remote spatiotemporal controllability, and unique convenience, demonstrate enticing advantages in the field of wound dressings. However, current research on magneto-responsive biocomposites as wound dressings lacks comprehensive and in-depth reviews, which to some extent, restricts the deeper understanding and further development of this field. Based on this, this paper reviews the latest advances in magnetic responsive wound dressings for wound healing. First, we review the process of skin wound healing and parameters for assessing repair progress. Then, we systematically discuss the preparation strategies and unique characteristics of magneto-responsive biocomposites, focusing on magneto-induced orientation, magneto-induced mechanical stimulation, and magnetocaloric effect. Subsequently, this review elaborates the multiple mechanisms of magneto-responsive biocomposites in promoting wound healing, including regulating cell behavior, enhancing electrical signal, controlling drug release, and accelerating tissue reconstruction. Finally, we further propose the development direction and future challenges of magnetic responsive biomaterials as wound dressings in clinical application.

Foam dressing and micropower vacuum dressing promote diabetic foot ulcer wound healing by activating the PI3K/AKT/mTOR pathway in rats

Foam dressing (FD) and micropower vacuum dressing (MVD) have been applied in the treatment of diabetic foot ulcer (DFU). However, research about the mode of action on the efficacy of the two dressings is extremely rare. This study proposed to explore the mechanism involved in diabetic wound healing under FD or MVD treatment. Macroscopical study was performed to evaluate the effectiveness of FD and MVD on wound healing in a rat model of DFU. Morphological analysis in the wound skin tissue was conducted by hematoxylin and eosin staining. Meanwhile, inflammatory cytokines in serum were measured by enzyme linked immunosorbent assay. The protein expression of phosphatidylinositol 3 kinase, protein kinase B and mammalian target of rapamycin (PI3K/AKT/mTOR) and their phosphorylation levels were determined by western blotting. We found that wound healing in rats with DFU was enhanced with the application of FD and MVD. The therapeutic efficacy of FD was superior to MVD. Compared with diabetic foot group, the concentrations of inflammatory cytokines, tumor necrosis factor alpha, interleukin-1β and interleukin-6, were significantly down-regulated. Besides, the phosphorylation levels of PI3K, AKT and mTOR were up-regulated under FD or MVD treatment. We demonstrated that the treatment of FD and MVD effectively promoted the wound skin healing through activating the PI3K/AKT/mTOR pathway. Our research may provide a new idea for exploring the mode of action of dressing application in healing of DFU.

Gram-negative bacteria recognition and photodynamic elimination by Zn-DPA based sensitizers

The abuse and overuse of antibiotics let drug-resistant bacteria emerges. Antibacterial photodynamic therapy (APDT) has shown outstanding merits to eliminate the drug-resistant bacteria via cytotoxic reactive oxygen species produced by irradiating photosensitizer. However, most of photosensitizers are not effective for Gram-negative bacteria elimination. Herein conjugates of NBS, a photosensitizer, linked with one (NBS-DPA-Zn) or two (NBS-2DPA-Zn) equivalents of zinc-dipicolylamine (Zn-DPA) have been designed to achieve the functional recognition of different bacteria. Due to the cationic character of NBS and metal transfer channel effect of Zn-DPA, NBS-DPA-Zn exhibited the first regent to distinguish P. aeruginosa from other Gram-negative bacteria. Whereas NBS-2DPA-Zn showed broad-spectrum antibacterial effect because the two arm of double Zn-DPA enhanced interactions with anionic membranes of bacteria, led the bacteria aggregation and thus provided the efficacy of APDT to bacteria and corresponding biofilm. In combination with a hydrogel of Pluronic, NBS-2DPA-Zn@gel shows promising clinical application in mixed bacterial diabetic mouse model infection. This might propose a new method that can realize functional identification and elimination of bacteria through intelligent regulation of Zn-DPA, and shows excellent potential for antibacterial application.

Study and evaluation of a gelatin- silver oxide nanoparticles releasing nitric oxide production of wound healing dressing for diabetic ulcer

This study aimed to develop a novel Gelatin silver oxide material for releasing nitric oxide bionanocomposite wound dressing with enhanced mechanical, chemical, and antibacterial properties for the treatment of diabetic wounds. The gelatin- silver oxide nanoparticles (Ag2O-NP) bio nanocomposite was prepared using chitosan and gelatin polymers incorporated with silver oxide nanoparticles through the freeze-drying method. The samples were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Results showed that the Ag2O-NP nanoparticles increased porosity, decreased pore size, and improved elastic modulus. The Ag2O-NP wound dressing exhibited the most effective antibacterial properties against Staphylococcus aureus and Escherichia coli. Among the samples, the wound dressing containing silver oxide nanoparticles demonstrated superior physical and mechanical properties, with 48% porosity, a tensile strength of 3.2 MPa, and an elastic modulus of 51.7 MPa. The fabricated wound dressings had a volume ratio of empty space to total volume ranging from 40% to 60%. In parallel, considering the complications of diabetes and its impact on the vascular system, another aspect of the research focused on developing a per2mediated wound dressing capable of releasing nitric oxide gas to regenerate damaged vessels and accelerate diabetic wound healing. Chitosan, a biocompatible and biodegradable polymer, was selected as the substrate for the wound dressing, and beta-glycerophosphate (GPβ), tripolyphosphate (TPP), and per2mediated alginate (AL) were used as crosslinkers. The chitosan-alginate (CS-AL) wound dressing exhibited optimal characteristics in terms of hole count and uniformity in the scanning electron microscope test. It also demonstrated superior water absorption (3854%) and minimal air permeability. Furthermore, the CS-AL sample exhibited an 80% degradation rate after 14 days, indicating its suitability as a wound dressing. The wound dressing was loaded with S-nitrosoglutathione (GSNO) powder, and the successful release of nitric oxide gas was confirmed through the grease test, showing a peak at a wavelength of 540 nm. Subsequent investigations revealed that the treatment of human umbilical vein endothelial cells (HUVECs) with high glucose led to a decrease in the expression of PER2 and SIRT1, while the expression of PER2 increased, which may subsequently enhance the expression of SIRT1 and promote cell proliferation activity. However, upon treatment of the cells with the modified materials, an increase in the expression of PER2 and SIRT1 was observed, resulting in a partial restoration of cell proliferative activity. This comprehensive study successfully developed per2-mediated bio-nanocomposite wound dressings with improved physical, mechanical, chemical, and antibacterial properties. The incorporation of silver oxide nanoparticles enhanced the antimicrobial activity, while the released nitric oxide gas from the dressing demonstrated the ability to mitigate vascular endothelial cell damage induced by high glucose levels. These advancements show promising potential for facilitating the healing process of diabetic wounds by addressing complications associated with diabetes and enhancing overall wound healing.

Hydrogel Wound Dressings Accelerating Healing Process of Wounds in Movable Parts

Skin is the largest organ in the human body and requires proper dressing to facilitate healing after an injury. Wounds on movable parts, such as the elbow, knee, wrist, and neck, usually undergo delayed and inefficient healing due to frequent movements. To better accommodate movable wounds, a variety of functional hydrogels have been successfully developed and used as flexible wound dressings. On the one hand, the mechanical properties, such as adhesion, stretchability, and self-healing, make these hydrogels suitable for mobile wounds and promote the healing process; on the other hand, the bioactivities, such as antibacterial and antioxidant performance, could further accelerate the wound healing process. In this review, we focus on the recent advances in hydrogel-based movable wound dressings and propose the challenges and perspectives of such dressings.

Scaffold-Mediated Drug Delivery for Enhanced Wound Healing: A Review

Wound healing is a complex physiological process involving coordinated cellular and molecular events aimed at restoring tissue integrity. Acute wounds typically progress through the sequential phases of hemostasis, inflammation, proliferation, and remodeling, while chronic wounds, such as venous leg ulcers and diabetic foot ulcers, often exhibit prolonged inflammation and impaired healing. Traditional wound dressings, while widely used, have limitations such poor moisture retention and biocompatibility. To address these challenges and improve patient outcomes, scaffold-mediated delivery systems have emerged as innovative approaches. They offer advantages in creating a conducive environment for wound healing by facilitating controlled and localized drug delivery. The manuscript explores scaffold-mediated delivery systems for wound healing applications, detailing the use of natural and synthetic polymers in scaffold fabrication. Additionally, various fabrication techniques are discussed for their potential in creating scaffolds with controlled drug release kinetics. Through a synthesis of experimental findings and current literature, this manuscript elucidates the promising potential of scaffold-mediated drug delivery in improving therapeutic outcomes and advancing wound care practices.

Dual Drug-Loaded Coaxial Nanofiber Dressings for the Treatment of Diabetic Foot Ulcer

Introduction

Diabetes mellitus is frequently associated with foot ulcers, which pose significant health risks and complications. Impaired wound healing in diabetic patients is attributed to multiple factors, including hyperglycemia, neuropathy, chronic inflammation, oxidative damage, and decreased vascularization.

Rationale

To address these challenges, this project aims to develop bioactive, fast-dissolving nanofiber dressings composed of polyvinylpyrrolidone loaded with a combination of an antibiotic (moxifloxacin or fusidic acid) and anti-inflammatory drug (pirfenidone) using electrospinning technique to prevent the bacterial growth, reduce inflammation, and expedite wound healing in diabetic wounds.

Results

The fabricated drug-loaded fibers exhibited diameters of 443 ± 67 nm for moxifloxacin/pirfenidone nanofibers and 488 ± 92 nm for fusidic acid/pirfenidone nanofibers. The encapsulation efficiency, drug loading and drug release studies for the moxifloxacin/pirfenidone nanofibers were found to be 70 ± 3% and 20 ± 1 µg/mg, respectively, for moxifloxacin, and 96 ± 6% and 28 ± 2 µg/mg, respectively, for pirfenidone, with a complete release of both drugs within 24 hours, whereas the fusidic acid/pirfenidone nanofibers were found to be 95 ± 6% and 28 ± 2 µg/mg, respectively, for fusidic acid and 102 ± 5% and 30 ± 2 µg/mg, respectively, for pirfenidone, with a release rate of 66% for fusidic acid and 80%, for pirfenidone after 24 hours. The efficacy of the prepared nanofiber formulations in accelerating wound healing was evaluated using an induced diabetic rat model. All tested formulations showed an earlier complete closure of the wound compared to the controls, which was also supported by the histopathological assessment. Notably, the combination of fusidic acid and pirfenidone nanofibers demonstrated wound healing acceleration on day 8, earlier than all tested groups.

Conclusion

These findings highlight the potential of the drug-loaded nanofibrous system as a promising medicated wound dressing for diabetic foot applications.

Preparation and characterization of a polyurethane-based sponge wound dressing with a superhydrophobic layer and an antimicrobial adherent hydrogel layer

Bacterial infection poses a significant impediment in wound healing, necessitating the development of dressings with intrinsic antimicrobial properties. In this study, a multilayered wound dressing (STPU@MTAI2/AM1) was reported, comprising a surface-superhydrophobic treated polyurethane (STPU) sponge scaffold coupled with an antimicrobial hydrogel. A superhydrophobic protective outer layer was established on the hydrophilic PU sponge through the application of fluorinated zinc oxide nanoparticles (F-ZnO NPs), thereby resistance to environmental contamination and bacterial invasion. The adhesive and antimicrobial inner layer was an attached hydrogel (MTAI2/AM1) synthesized through the copolymerization of N-[2-(methacryloyloxy)ethyl]-N, N, N-trimethylammonium iodide and acrylamide, exhibits potent adherence to dermal surfaces and broad-spectrum antimicrobial actions against resilient bacterial strains and biofilm formation. STPU@MTAI2/AM1 maintained breathability and flexibility, ensuring comfort and conformity to the wound site. Biocompatibility of the multilayered dressing was demonstrated through hemocompatibility and cytocompatibility studies. The multilayered wound dressing has demonstrated the ability to promote wound healing when addressing MRSA-infected wounds. The hydrogel layer demonstrates no secondary damage when peeled off compared to commercial polyurethane sponge dressing. The STPU@MTAI2/AM1-treated wounds were nearly completely healed by day 14, with an average wound area of 12.2 ± 4.3 %, significantly lower than other groups. Furthermore, the expression of CD31 was significantly higher in the STPU@MTAI2/AM1 group compared to other groups, promoting angiogenesis in the wound and thereby contributing to wound healing. Therefore, the prepared multilayered wound dressing presents a promising therapeutic candidate for the management of infected wounds. STATEMENT OF SIGNIFICANCE: Healing of chronic wounds requires avoidance of biofouling and bacterial infection. However developing a wound dressing which is both anti-biofouling and antimicrobial is a challenge. A multilayered wound dressing with multifunction was developed. Its outer layer was designed to be superhydrophobic and thus anti-biofouling, and its inner layer was broad-spectrum antimicrobial and could inhibit biofilm formation. The multilayered wound dressing with adhesive property could easily be removed from the wound surface preventing the cause of secondary damage. The multilayered wound dressing has demonstrated good abilities to promote MRSA-infected wound healing and presents a viable treatment for MRSA-infected wound.

An in vitro and in vivo study of electrospun polyvinyl alcohol/chitosan/sildenafil citrate mat on 3D-printed polycaprolactone membrane as a double layer wound dressing

Double-layer dermal substitutes (DS) generally provide more effective therapeutic outcomes than single-layer substitutes. The architectural design of DS incorporates an outer layer to protect against bacterial invasions and maintain wound hydration, thereby reducing the risk of infection and the frequency of dressing changes. Moreover, the outer layer is a mechanical support for the wound, preventing undue tension in the affected area. A 3D-printed polycaprolactone (PCL) membrane was utilized as the outer layer to fabricate DS wound dressing. Simultaneously, a polyvinyl alcohol/chitosan/sildenafil citrate (PVA/CS/SC) scaffold was electrospun onto the PCL membrane to facilitate cellular adhesion and proliferation. Scanning electron microscopy (SEM) analysis of the PCL filaments revealed a consistent cross-sectional surface and structure, with an average diameter of 562.72 ± 29.15 μm. SEM results also demonstrated uniform morphology and beadless structure for the PVA/CS/SC scaffold, with an average fiber diameter of 366.77 ± 1.81 nm for PVA/CS. The addition of SC led to an increase in fiber diameter while resulting in a reduction in tensile strength. However, drug release analysis indicated that the SC release from the sample can last up to 72 h. Animal experimentation confirmed that DS wound dressing positively accelerated wound closure and collagen deposition in the Wistar rat skin wound model.

Promoting the healing of diabetic wounds with an antimicrobial gel containing AgNPs with anti-infective and anti-inflammatory properties

Diabetic wounds are prone to develop chronic wounds due to bacterial infection and persistent inflammatory response. However, traditional dressings are monofunctional, lack bioactive substances, have limited bacterial inhibition as well as difficulties in adhesion and retention. These limit the therapeutic efficacy of traditional dressings on diabetic wounds. Therefore, finding and developing efficient and safe wound dressings is currently an urgent clinical need. In this study, an antimicrobial gel loaded with silver nanoparticles (AgNPs) (referred to as AgNPs@QAC-CBM) was prepared by crosslinking quaternary ammonium chitosan (QAC) with carbomer (CBM) as a gel matrix. AgNPs@QAC-CBM exhibited a reticulated structure, strong adhesion, good stability, and remarkable bactericidal properties, killing 99.9% of Escherichia coli, Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa within 1 min. Furthermore, AgNPs@QAC-CBM improved the wound microenvironment and accelerated wound healing in diabetic mice by promoting tissue production and collagen deposition, inducing M2 macrophages, reducing pro-inflammatory factor secretion and increasing anti-inflammatory factor levels. Moreover, AgNPs@QAC-CBM was proven to be safe for use through skin irritation and cytotoxicity tests, as they did not cause any irritation or toxicity. To summarize, AgNPs@QAC-CBM showed promising potential in enhancing the diabetic wound healing process.

A Viscous-Biofluid Self-Pumping Organohydrogel Dressing to Accelerate Diabetic Wound Healing

Viscous biofluids on wounds challenge conventional "water-absorbing" wound dressings in efficient drainage due to their poor fluidity, generally causing prolonged inflammation, anti-angiogenesis, and delayed wound closure. Herein, it is reported that a self-pumping organohydrogel dressing (SPD) with aligned hydrated hydrogel channels, prepared by a three-dimensional-templated wetting-enabled-transfer (3D-WET) polymerization process, can efficiently drain viscous fluids and accelerate diabetic wound healing. The asymmetric wettability of the hydrophobic-hydrophilic layers and aligned hydrated hydrogel channels enable unidirectional and efficient drainage of viscous fluids away from the wounds, preventing their overhydration and inflammatory stimulation. The organogel layer can adhere onto the skin around the wounds but can be easily detached from the wet wound area, avoiding secondary trauma to the newly formed tissues. Taking a diabetic rat model as an example, the SPD can significantly downregulate the inflammation response by ≈70.8%, enhance the dermal remodeling by ≈14.3%, and shorten wound closure time by about 1/3 compared with the commercial dressing (3M, Tegaderm hydrocolloid thin dressing). This study sheds light on the development of the next generation of functional dressings for chronic wounds involving viscous biofluids.

Therapeutic Potential of Nanocarrier Mediated Delivery of Peptides for Wound Healing: Current Status, Challenges and Future Prospective

Wound healing presents a complex physiological process that involves a sequence of events orchestrated by various cellular and molecular mechanisms. In recent years, there has been growing interest in leveraging nanomaterials and peptides to enhance wound healing outcomes. Nanocarriers offer unique properties such as high surface area-to-volume ratio, tunable physicochemical characteristics, and the ability to deliver therapeutic agents in a controlled manner. Similarly, peptides, with their diverse biological activities and low immunogenicity, hold great promise as therapeutics in wound healing applications. In this review, authors explore the potential of peptides as bioactive components in wound healing formulations, focusing on their antimicrobial, anti-inflammatory, and pro-regenerative properties. Despite the significant progress made in this field, several challenges remain, including the need for standardized characterization methods, optimization of biocompatibility and safety profiles, and translation from bench to bedside. Furthermore, developing multifunctional nanomaterial-peptide hybrid systems represents promising avenues for future research. Overall, the integration of nanomaterials made up of natural or synthetic polymers with peptide-based formulations holds tremendous therapeutic potential in advancing the field of wound healing and improving clinical outcomes for patients with acute and chronic wounds.

Non-Covalent Cross-Linking Hydrogel: A New Method for Visceral Hemostasis

Excessive blood loss could lead to pathological conditions such as tissue necrosis, organ failure, and death. The limitations of recently developed hemostatic approaches, such as their low mechanical strength, inadequate wet tissue adhesion, and weak hemostatic activity, pose challenges for their application in controlling visceral bleeding. In this study, a novel hydrogel (CT) made of collagen and tannic acid (TA) was proposed. By altering the proportions between the two materials, the mechanical properties, adhesion, and coagulation ability were evaluated. Compared to commercial hydrogels, this hydrogel has shown reduced blood loss and shorter hemostatic time in rat hepatic and cardiac bleeding models. This was explained by the hydrogel's natural hemostatic properties and the significant benefits of wound closure in a moist environment. Better biodegradability was achieved through the non-covalent connection between tannic acid and collagen, allowing for hemostasis without hindering subsequent tissue repair. Therefore, this hydrogel is a new method for visceral hemostasis that offers significant advantages in treating acute wounds and controlling major bleeding. And the production method is simple and efficient, which facilitates its translation to clinical applications.

Collagen/chitosan/genipin hydrogel loaded with phycocyanin nanoparticles and ND-336 for diabetic wound healing

Diabetic wound healing remains a healthcare challenge due to the overexpression of matrix metalloproteinase-9 (MMP-9) and the imbalance between angiogenic factors and vascular inhibitory factors. In this study, we developed a nanocomposite injectable collagen/chitosan hydrogel for the treatment of delayed diabetic wound healing, which can promote cell migration to the wound site (through the addition of phycocyanin) and reduce the expression of MMP-9 (through the use of ND-336) to improve the therapeutic effect of diabetic wound healing. Furthermore, different weight ratios of collagen and chitosan hydrogels were prepared to select the hydrogel with proper mechanical properties. In vitro experiments confirmed that all hydrogels have favorable biocompatibility and hemocompatibility. Notably, Gel 2, with a weight ratio of collagen and chitosan at 25:75, was found to have an excellent capability to facilitate cell migration and in vivo studies further proved that Gel 2 nanocomposite hydrogel had the best ability to improve diabetic wound healing by promoting cell migration and decreasing MMP-9 expression. The collagen/chitosan/genipin hydrogel loaded phycocyanin and ND-336 can be harnessed for non-toxic and efficient treatment of wound healing management of diabetes.

Acellular fish skin grafts in the treatment of diabetic wounds: Advantages and clinical translation

Diabetic wounds cannot undergo normal wound healing due to changes in the concentration of hyperglycemia in the body and soon evolve into chronic wounds causing amputation or even death of patients. Diabetic wounds directly affect the quality of patients and social medical management; thus researchers started to focus on skin transplantation technology. The acellular fish skin grafts (AFSGs) are derived from wild fish, which avoids the influence of human immune function and the spread of the virus through low-cost decellularization. AFSGs contain a large amount of collagen and omega-3 polyunsaturated fatty acids and they have an amazing effect on wound regeneration. However, after our search in major databases, we found that there were few research trials in this field, and only one was clinically approved. Therefore, we summarized the advantages of AFSGs and listed the problems faced in clinical use. The purpose of this paper is to enable researchers to better carry out original experiments at various stages.

Advanced multifunctional hydrogels for diabetic foot ulcer healing: Active substances and biological functions

AIM

Hydrogels with excellent biocompatibility and biodegradability can be used as the desirable dressings for the therapy of diabetic foot ulcer (DFU). This review aimed to summarize the biological functions of hydrogels, combining with the pathogenesis of DFU.

METHODS

The studies in the last 10 years were searched and summarized from the online database PubMed using a combination of keywords such as hydrogel and diabetes. The biological functions of hydrogels and their healing mechanism on DFU were elaborated.

RESULTS

In this review, hydrogels were classified by their active substances such as drugs, cytokines, photosensitizers, and biomimetic peptide. Based on this, the biological functions of hydrogels were summarized by associating the pathogenesis of DFU, including oxidative stress, chronic inflammation, cell phenotype change, vasculopathy, and infection. This review also pointed out some of the shortcomings of hydrogels in present researches.

CONCLUSIONS

Hydrogels were classified into carrier hydrogels and self-functioning hydrogels in this review. Besides, the functions and components of existing hydrogels were clarified to provide assistance for future researches and clinical applications.

Mesenchymal stem cell therapy in diabetic foot ulcer: An updated comprehensive review

Background

Diabetes has evolved into a worldwide public health issue. One of the most serious complications of diabetes is diabetic foot ulcer (DFU), which frequently creates a significant financial strain on patients and lowers their quality of life. Up until now, there has been no curative therapy for DFU, only symptomatic relief or an interruption in the disease's progression. Recent studies have focused attention on mesenchymal stem cells (MSCs), which provide innovative and potential treatment candidates for several illnesses as they can differentiate into various cell types. They are mostly extracted from the placenta, adipose tissue, umbilical cord (UC), and bone marrow (BM). Regardless of their origin, they show comparable features and small deviations. Our goal is to investigate MSCs' therapeutic effects, application obstacles, and patient benefit strategies for DFU therapy.

Methodology

A comprehensive search was conducted using specific keywords relating to DFU, MSCs, and connected topics in the databases of Medline, Scopus, Web of Science, and PubMed. The main focus of the selection criteria was on English-language literature that explored the relationship between DFU, MSCs, and related factors.

Results and Discussion

Numerous studies are being conducted and have demonstrated that MSCs can induce re-epithelialization and angiogenesis, decrease inflammation, contribute to immunological modulation, and subsequently promote DFU healing, making them a promising approach to treating DFU. This review article provides a general snapshot of DFU (including clinical presentation, risk factors and etiopathogenesis, and conventional treatment) and discusses the clinical progress of MSCs in the management of DFU, taking into consideration the side effects and challenges during the application of MSCs and how to overcome these challenges to achieve maximum benefits.

Conclusion

The incorporation of MSCs in the management of DFU highlights their potential as a feasible therapeutic strategy. Establishing a comprehensive understanding of the complex relationship between DFU pathophysiology, MSC therapies, and related obstacles is essential for optimizing therapy outcomes and maximizing patient benefits.

Highly Absorbent Egg White/Carbomer-940 Hydrofilm as a Potential Diabetic Wound Dressing

Diabetic foot ulcer (DFU) is the most critical problem in diabetic patients. Managing exudate in this kind of wound presents significant challenges in clinics. Advanced wound dressings serve as the most effective approach to managing DFU. Herein, a highly absorbent hydrofilm is presented through a combination of egg white (EW) and Carbomer-940, benefiting from the bioactivity of the EW component and superabsorption capacity of Carbomer-940. The crystallinity of samples rises due to the presence of Carbomer-940. Regarding the high water absorption capacity of Carbomer-940, the swelling ratio and water-holding capacity of samples are also improved via its incorporation of up to 1005%. In contrast, the transmission of water vapor and in vitro degradation rate decreases as Carbomer-940 powers the crystallinity of hydrofilms. Carbomer-940 incorporation in the EW structure accelerates protein release during the time, while this acceleration is partially compensated by the crystallization effect. The cell viability assay demonstrates no toxicity as well as high human foreskin fibroblast cell proliferation for the hybrid hydrofilm sample, where the cell migration is positively affected in the presence of the bioactive components extracted from the dressing. Taken together, the optimized hybrid hydrofilm could be suggested as a promising wound dressing for managing DFUs.

Exploring polysaccharide-based bio-adhesive topical film as a potential platform for wound dressing application: A review

Wound dressings act as a physical barrier between the wound site and the external environment, preventing additional harm; choosing suitable wound dressings is essential for the healing process. Polysaccharide biopolymers have demonstrated encouraging findings and therapeutic prospects in recent decades about wound therapy. Additionally, polysaccharides have bioactive qualities like anti-inflammatory, antibacterial, and antioxidant capabilities that can help the process of healing. Due to their excellent tissue adhesion, swelling, water absorption, bactericidal, and immune-regulating properties, polysaccharide-based bio-adhesive films have recently been investigated as intriguing alternatives in wound management. These films also mimic the structure of the skin and stimulate the regeneration of the skin. This review presented several design standards and functions of suitable bio-adhesive films for the healing of wounds. Additionally, the most recent developments in the use of bio-adhesive films as wound dressings based on polysaccharides, including hyaluronic acid, chondroitin sulfate, dextran, alginate, chitosan, cellulose, konjac glucomannan, gellan gum, xanthan gum, pectin, guar gum, heparin, arabinogalactans, carrageen, and tragacanth gum, are thoroughly discussed. Lastly, to create a road map for the function of polysaccharide-based bio-adhesive films in advanced wound care, their clinical performances and future challenges in making bio-adhesive films by three-dimensional bioprinting are summarized.

Engineered keratin/bFGF hydrogel to promote diabetic wound healing in rats

Keratin materials are promising in wound healing acceleration, however, it is a challenge for the keratin to efficiently therapy the impaired wound healing, such as diabetic foot ulcers. Here, we report a keratin/bFGF hydrogel for skin repair of chronic wounds in diabetic rats based on their characteristics of extracellular matrix and growth factor degradation in diabetic ulcer. Recombinant keratin 31 (K31), the most abundant keratin in human hair, exhibited the highly efficient performances in cell adhesion, proliferation and migration. More importantly, the introduction of bFGF into K31 hydrogel significantly enhances the properties of cell proliferation, wound closure acceleration, angiogenesis and skin appendages regeneration. Furthermore, the combination of K31 and bFGF can promote epithelial-mesenchymal transition by inhibiting the expression of E-cadherin and promoting the expression of vimentin and fibronectin. These findings demonstrate the engineered K31/bFGF hydrogel as a promising therapeutic agent for diabetic wound healing.

Comorbidities Associated With Increased Likelihood of Postoperative Surgical Site Infection in Patients Treated for Hand or Finger Fracture and/or Dislocations

BACKGROUND

We aimed to determine the relationship between common preoperative comorbidities and subsequent incidence of postoperative surgical site infections (SSIs) in hand and finger fractures and/or dislocations.

METHODS

We queried the American College of Surgeons National Safety and Quality Improvement Program from January 1, 2015 to December 31, 2019. Patients were included in our study if they were treated by open or percutaneous fixation for any hand or finger fracture and/or dislocation. Predictor variables were smoking status, diabetes mellitus status, and obesity (body mass index > 30) status. Primary outcome was incidence of postoperative SSI.

RESULTS

There were a total of 9245 patients included in our study, and 148 patients (1.6%) experienced postoperative SSI. Of these, 59 patients (39.9%) were only smokers, 7 patients (4.7%) only had diabetes mellitus, and 55 patients (37.2%) were only obese. Overall, patients experienced greater odds of sustaining a postoperative SSI if they were a smoker or diabetic compared to non-smokers and non-diabetics, respectively. Considering only open fixation modality, patients with comorbidities were not at significantly increased odds of sustaining postoperative SSI. Considering only percutaneous fixation modality, patients experienced significantly greater odds of sustaining postoperative SSI if they were a smoker compared to non-smoker.

CONCLUSIONS

Common preoperative comorbidities, including smoking status and diabetes mellitus, increase the likelihood of postoperative complication in patients with hand and finger fractures and/or dislocations undergoing surgical treatment. Further investigation into the different relationship of these comorbidities between open and closed fractures with larger sample sizes will be valuable.

Chitosan-polygalacturonic acid complex dressing improves diabetic wound healing and hair growth in diabetic mice

Chronic skin wounds decrease the quality of life of millions of diabetic patients worldwide. Chitosan has previously been shown to possess hemostatic properties, decrease inflammation, promote fibroblast proliferation, and hair growth. We developed a relatively low-cost polyelectrolyte complex (PEC) film dressing made of chitosan and polygalacturonic acid and tested it for its ability to accelerate diabetic wound healing. Genetically diabetic male mice were shaved on the dorsum, and one day later a 1 cm diameter full-thickness excisional wound was created. The PEC film was applied immediately after wounding and left in place for 14 days. Controls consisted of wounds treated with a fibrin gel. Wounds covered with the PEC film had closed completely by post-wounding day 42, while untreated wounds were only half-way closed. Histological analysis of wounds confirmed that PEC-treated wounds had fully re-epithelialized, while control wounds lacked a continuous epidermis at the wound center. We also observed that the area of skin under the PEC film experienced much more rapid hair growth. Histologically, there were significantly more hair follicles around the scar area (p < 0.05) in the PEC-treated group as compared to the control group. Thus, chitosan-polygalacturonic acid PEC films can accelerate both wound healing and hair growth in diabetic mice, and should be further investigated as a potential future treatment for diabetic chronic wounds.

Sprayable hydroxypropyl chitin/collagen extract of Ampelopsis brevipedunculata hydrogel accelerates wound healing

OBJECTIVE

Keeping a wound moist can allow effective and rapid healing, and it can control the formation of scabs, thereby allowing cell proliferation and epithelial formation. When regularly changing a dressing, thermosensitive hydrogel as a moist dressing does not cause a secondary wound from adhesion. The main aim of this study was to evaluate the effect of a new sprayable thermosensitive hydrogel on wound healing.

METHOD

The hydrophobic N-acetyl group of chitin was removed by microwave reaction with lye until the degree of acetylation was 60%, followed by reaction with propylene oxide to obtain hydroxypropyl chitin (HPCH) with a degree of substitution of 40%. After mixing HPCH with fish scale collagen (FSC), a thermosensitive hydrogel with a gel temperature of 26.5°C was obtained. Ampelopsis brevipedunculata extracts (ABE), which have been found to accelerate wound repair and improve healing, were added. HPCH/FSC is not toxic to the mouse L929 cell line and forms a hydrogel at body surface temperature. It can be easily sprayed on a wound. The HPCH/FSC has a three-dimensional network porous structure with a swelling ratio of 10.95:1 and a water vapour transmission rate of 2386.03±228.87g/m2/day; it can facilitate the penetration of water and air, and promote absorption of wound exudate. Wound repair was performed on five Sprague-Dawley rats. Each rat had three wounds, which were treated with medical gauze, HPCH/FSC and HPCH/FSC/ABE, respectively.

RESULTS

The wounds in the HPCH/FSC/ABE group recovered the fastest in vivo, the mature wound site was smoother, the re-epithelialisation was even and thicker, and the angiogenesis developed rapidly to the mature stage.

CONCLUSION

In this study, HPCH/FSC/ABE thermosensitive hydrogel was shown to effectively accelerate wound healing and was convenient for practical application.

A Smart Stimulation-Deadhesion and Antimicrobial Hydrogel for Repairing Diabetic Wounds Infected with Methicillin-Resistant Staphylococcus aureus

The healing of chronic diabetic wounds is a common and significant challenge in the medical field. Despite extensive efforts, the development of hydrogel dressings with satisfactory functionality remains an ongoing concern. In this study, a multifunctional hydrogel wound dressing (PAN/Ag-PLG) with adhesion, antibacterial, hemostatic, and other properties, which can effectively repair diabetic wounds infected with methicillin-resistant Staphylococcus aureus (MRSA), is presented. The hydrogel dressing is composed of gallic acid (GA)-functionalized polylysine (PL)-reduced silver nanoparticles (Ag-PLG), oxidized hyaluronic acid (OHA), and cross-linked polyacrylic acid grafted with N-hydrosuccinimide ester. Notably, compared to most conventional wound dressing that lack adhesion or are difficult to remove, the prepared hydrogels exhibit excellent adhesion and mild stimulation-triggered detachment. In vitro and in vivo experiments reveal that the PAN/Ag-PLG hydrogel exhibits outstanding biocompatibility and antibacterial properties and promotes diabetic wound repair by reducing oxidative damage and promoting cell migration and angiogenesis. The smart PAN/Ag-PLG hydrogel reported in this study provides an approach for the potential clinical development of painless antibacterial dressings.

Unique combination of hyaluronic acid and amino acids in the management of patients with a wide range of moderate-to-severe chronic wounds: Evidence from international clinical practice

The availability of new products and strategies to manage wounds has taken a quantum leap in recent years. Healthcare professionals now have an extensive range of products to choose from, but while positive this also raises dilemmas in real-world clinical practice to decide on the most appropriate treatment for a given patient. Clinical trials confirm the effectiveness of the unique combination of hyaluronic acid and amino acids (Vulnamin®) in a range of wounds, but are these results replicated in real-world clinical practice? International experts presented their clinical experience with the use of the combination in difficult-to-treat wounds. The objective was to reach a consensus on how and when to use the unique combination products to provide a cost-effective, convenient option, in all healthcare settings that improves QoL for patients and their carers.

Bilayer wound dressing composed of asymmetric polycaprolactone membrane and chitosan-carrageenan hydrogel incorporating storax balsam

A comprehensive approach is needed to develop multifunctional wound dressing that is simple yet efficient. In this work, Liquidambar orientalis Mill. storax loaded hydroxyethyl chitosan (HECS)-carrageenan (kC) based hydrogel (HECS-kC) and polydopamine coated asymmetric polycaprolactone membrane (PCL-DOP) were used to develop a multifunctional and modular bilayer wound dressing. Asymmetric PCL-DOP membrane was prepared by non-solvent induced phase separation (NIPS) followed by polydopamine coating and demonstrated an excellent barrier against bacteria while allowing permeability for 5.45 ppm dissolved‑oxygen and 2130 g/m2 water vapor transmission in 24 h in addition to 805 kPa tensile strength. Storax loaded HECS-kC hydrogel, on the other hand, demonstrated a pH-responsive degradation and swelling to provide necessary conditions to facilitate wound healing. The hydrogels showed stretchability above 140 %, mild adhesive strength on sheep skin and PCL-DOP membrane, while the storax incorporation enhanced antibacterial and antioxidant activity. Furthermore, rat full-thickness skin defect model showed that the developed bilayer wound dressing could significantly facilitate wound healing compared to Tegaderm™ and control groups. This study shows that the bilayered wound dressing has the potential to be used as a simple and effective wound care system.

A Novel Potential Treatment for Diabetic Foot Ulcers and Non-Healing Ulcers - Case Series

Introduction: Appropriate care and treatment of a wound is the need of the hour whether it is an infected or a non-infected wound. If wound healing is delayed for some reason, it leads to serious complications and further increases the hospital stay and cost of treatment. Herein, we describe a novel antimicrobial wound dressing formulation (VG111), with an objective to generate the preliminary data showing the distinct advantages in various types of wounds.

Method: This case series involved the treatment of acute cases of wounds or chronic wounds that did not respond well to conventional wound healing treatments with VG111 in patients with different etiologies. Thirteen cases of patients that included patients with diabetes, pressure ulcers, burns, trauma, and others treated with VG111 showed rapid wound healing in all the cases, even obviating the need for a graft when complete skin regeneration occurred.

Result: This was illustrated by clearing of the wound infections, reduction/disappearance of the exudate, appearance of intense granulation, epithelialization, and anti-biofilm activity followed by complete wound closure. This VG111 precludes the need for systemic antimicrobial agents in localized infections and therefore, this single agent is an attempt to address the limitations and the drawbacks of the available products.

Conclusion: Despite patients belonging to the old age group and having comorbidities like diabetes, still VG111 showed effective rapid wound healing, and that too without any scar formation in hardto- heal, infected, and non-infected wounds.

.

Enhancement of Oral Bioavailability of Protein and Peptide by Polysaccharide-based Nanoparticles

Oral drug delivery is a prevalent and cost-effective method due to its advantages, such as increased drug absorption surface area and improved patient compliance. However, delivering proteins and peptides orally remains a challenge due to their vulnerability to degradation by digestive enzymes, stomach acids, and limited intestinal membrane permeability, resulting in poor bioavailability. The use of nanotechnology has emerged as a promising solution to enhance the bioavailability of these vital therapeutic agents. Polymeric NPs, made from natural or synthetic polymers, are commonly used. Natural polysaccharides, such as alginate, chitosan, dextran, starch, pectin, etc., have gained preference due to their biodegradability, biocompatibility, and versatility in encapsulating various drug types. Their hydrophobic-hydrophilic properties can be tailored to suit different drug molecules.

Enhancing diabetic wound healing with a pH-responsive nanozyme hydrogel featuring multi-enzyme-like activities and oxygen self-supply

Diabetic wound treating remains a challenging due to bacterial infections, oxidative stress, tissue hypoxia, and high glucose levels. Herein, a multi-enzyme-like activities nanocomposite (Mo,Fe/Cu,I-Ag@GOx) was designed and anchored to a multifunctional fluorescence hydrogel. The nanozyme gel, loaded with glucose-oxidase (GOx), exhibits intrinsic GOx, peroxidase (POD)-, oxidase (OXD)-, catalase (CAT)- and superoxide dismutase (SOD)-like activities with pH-switchable glucose-initiated cascade reaction for diabetic wound healing. In the first cascade-reaction, initiated by GOx, the nanozyme gel catalyzes glucose and O2 into gluconic acid and H2O2 to further generate superoxide anion radical (O2·-) and hydroxyl radicals (·OH) to eradicate bacteria. In the second cascade-reaction, as the wound pH changes alkalescent microenvironment, the nanozyme gel simulates SOD to transform O2·- into O2 and H2O2, and then decomposes endogenous and exogenous H2O2 into O2 via CAT-like activity to reduce oxidative stress and alleviate hypoxia. The gel by calcium ion (Ca2+) cross-linked sodium alginate (SA) and chitosan (CS) containing nanozyme was constructed with injectability, adhesion and fluorescence properties, as well as beneficial biocompatible. Importantly, the water/alcohol solubility of the nanozyme gel allows it to be used as a dressing without causing secondary injury to the wound. The multifunctional fluorescence hydrogel exhibits efficiently promote pro-angiogenesis and bacteria-infected wound healing.

Stem Cell-Based Tissue Engineering Approaches for Diabetic Foot Ulcer: a Review from Mechanism to Clinical Trial

Diabetic foot ulcer (DFU) is a complication from incomplete or prolonged wound healing, at times requires amputation, putting substantial health and socioeconomic burden. Wound healing is a dynamic overlapping process that can be regulated by arrays of molecular factors showing redundancy in function. However, dysregulation in the mechanism of angiogenesis, extra cellular matrix (ECM) formation and immune modulation are the major causes for impair wound healing in hyperglycaemic patients. Despite development of wound care research, there is a lack of well-accepted targeted therapy with multidisciplinary approach for DFU treatment. Stem cell therapy holds a promising outcome both in preclinical and clinical trials because of its ability to promote healing via regeneration and specialized tissue differentiation. Among different types of stem cells, regenerative potential of mesenchymal stem cell (MSC) is well demonstrated in both experimental and clinical trial. Still there is a huge knowledge gap among medical practitioners for deciding the best stem cell source, administration route, and safety. This review strengthens the fact that why stem cell therapy is a promising candidate to treat DFU and cited multiple tissue engineering and biomaterial-based approaches for delivering stem cells and their aftermath paracrine events. Based on the pre-clinical and clinical studies, the review tried to come up with optimum stem cell source and delivery route for the treatment of DFU. At last, the review glances on possible direction to enhance therapeutics strategy for the same, including different approaches like: phytocompounds, exosomes, scaffold geometry, cell preconditioning and licensing etc.

Preparation and evaluation of Angelica sinensis polysaccharide-modified chitosan sponge for acute liver injury protection

In this study, a porous sponge material was formed by physically mixing chitosan (CS) and Angelica sinensis polysaccharide (ASP). After removing the water by freeze-drying, the CS/ASP sponge was obtained. The prepared sponges exhibited excellent swelling properties, thermal stability and biocompatibility as well as improvements over the insufficient mechanical properties of pure chitosan sponges. Notably, the ASP released from the CS/ASP sponge could be effectively absorbed by the liver, which endowed the CS/ASP sponge with effective liver-protective effects against CCl4-induced acute liver injury; these protective effects surpassed those of both blank CS and CS/Dextran sponges. The underlying protective mechanism may involve the activation of the Nrf2-mediated antioxidant signaling pathway and the inhibition of hepatocyte apoptosis. Understanding CS/ASP sponges may provide new insights and inspire new methods for the clinical application of ASP. At the same time, we hope to suggest future directions for the development of polysaccharide preparations.

Development of gallic acid-loaded ethylcellulose fibers as a potential wound dressing material

In this study, novel fibers were designed based on ethylcellulose (EC), loaded with different concentrations of gallic acid (GA) using the electrospinning technique, in order to investigate the potential of these materials as wound dressings. The chemical structure and morphology, along with the antimicrobial and biocompatibility tests of the EC_GA fibers were investigated. To observe the chemical interactions between the components, fourier transform infrared spectroscopy (FTIR) was used. The morphological analyzes were performed using scanning electron microscope (SEM). The uniaxial tensile test machine was used to obtain mechanical performance of the fibers. MTT assay was applied to get the biocompatibility properties of the fibers and antimicrobial test was applied to obtain the antimicrobial activity of the fibers. Based on the obtained results, the highest viability value of 67.4 % was obtained for 10%EC_100GA on the third day of incubation, demonstrating that with the addition of a higher concentration of GA, the cell viability increases. The antimicrobial tests, evaluated against Staphylococcus (S.) aureus, Escherichia (E.) coli, Pseudomonas (Ps.) aeruginosa and Candida (C.) albicans, showed a >90 % microbial reduction capacity correlated with a logarithmic reduction ranging from 0.63 to 1, for 10%EC_100 GA. In vitro release tests of GA from the fibers showed that GA was totally released from 10%EC_100 GA fibers after 2880 min, demonstrating a controlled release profile. These findings demonstrated that EC_GA fibers may be suitable for application in biomedical fields such as wound dressing materials. However, further studies should be performed to increase the biocompatibility properties of the fibers.

Hydrogen sulfide releasing poly(γ-glutamic acid) biocomposite hydrogel with monitoring, antioxidant, and antibacterial properties for diabetic wound healing

Adverse factors such as high levels of glucose, oxidative stress, inflammation, and bacterial infection impede diabetic wound healing and even worsen wounds. Owing to its outstanding anti-inflammatory and antioxidant properties as well as the potential to promote cell migration and proliferation, hydrogen sulfide(H2S) gas therapy is promising for chronic diabetic wound recovery. In this work, a multifunctional poly(γ-glutamic acid)(PGA) hydrogel encapsulated with keratin-based H2S donor(KTC), ciprofloxacin(Cip), and anthocyanins(Ant) was developed. The resultant hydrogel was capable of releasing H2S, thereby promoting cell proliferation and enhancing anti-inflammation and antioxidant activity. The release of antibiotic Cip was accelerated under a diabetic wound microenvironment, thereby enhancing the antibacterial activity of the hydrogel. The encapsulated Ant could serve as a pH monitor, sensitively indicating wound pH conditions in situ and indirectly reflecting wound infection. In vivo results in diabetic wound healing suggested that PGA/Ant/KTC/Cip hydrogel reduced inflammation and promoted angiogenesis and collagen deposition, thereby accelerating wound healing.

Soy protein/β-chitin sponge-like scaffolds laden with human mesenchymal stromal cells from hair follicle or adipose tissue promote diabetic chronic wound healing

Chronic wounds are a worldwide problem that affect >40 million people every year. The constant inflammatory status accompanied by prolonged bacterial infections reduce patient's quality of life and life expectancy drastically. An important cell type involved in the wound healing process are mesenchymal stromal cells (MSCs) due to their long-term demonstrated immunomodulatory and pro-regenerative capacity. Thus, in this work, we leveraged and compared the therapeutic properties of MSCs derived from both adipose tissue and hair follicle, which we combined with sponge-like scaffolds (SLS) made of valorized soy protein and β-chitin. In this regard, the combination of these cells with biomaterials permitted us to obtain a multifunctional therapy that allowed high cell retention and growing rates while maintaining adequate cell-viability for several days. Furthermore, this combined therapy demonstrated to increase fibroblasts and keratinocytes migration, promote human umbilical vein endothelial cells angiogenesis and protect fibroblasts from highly proteolytic environments. Finally, this combined therapy demonstrated to be highly effective in reducing wound healing time in vivo with only one treatment change during all the experimental procedure, also promoting a more functional and native-like healed skin.

Adjunctive topical oxygen therapy in the management of complex diabetes-related wounds: A South African case study series

Diabetic foot ulcers (DFUs) are a prevalent complication of diabetes mellitus and are associated with significant morbidity and mortality. The essential role of oxygen in the treatment of DFUs is documented. Indicated for use on a variety of wound types, topical haemoglobin therapy (Granulox®) is a novel therapeutic technology that binds atmospheric oxygen and improves the availability of oxygen at the wound site. When used as part of the wound management strategy, this therapy helps to reduce inflammation, exudate and slough, and promotes wound healing. In South Africa, health resources, coordinated foot care and podiatry, and data on diabetic foot complications are limited. Twelve patient case studies assessing the impact of adding topical haemoglobin therapy to the management regimes for DFUs and surgical (post-amputation) wounds were undertaken in South Africa. Patients were aged 50-71 years, and all had diabetes mellitus. At baseline, the area of the wounds ranged from 10.2 to 149.6 cm2 with depths ranging from 0.2 to 0.9 cm. Clinical signs of wound infection and high levels of viscous exudate were recorded in all cases. Wound dressings were changed twice weekly and sharp debridement of the wound performed as necessary. The wounds were cleansed and then completely coated with a thin film of Granulox® and dressings applied. Treatment was monitored over periods ranging from 57 to 276 days, during which dressings were changed and Granulox® administered to the wounds, ranging from 16 to 79 times. During the period of evaluation, wound size steadily reduced (by 87.1-100%), the condition of the wound bed tissue and peri-wound skin improved, and clinical signs of wound infection steadily resolved. Wounds significantly improved in two patients, almost healed in six patients, and healed in four patients. All patients reported a reduction in malodour and pain; seven patients were pain-free at the final followup assessment. The overall impression of Granulox® was rated as 'very good' by the clinicians, who considered that Granulox® facilitated an increase in tissue viability, with the promotion of granulation tissue, and stimulated epithelialisation.

Nanotechnology development in surgical applications: recent trends and developments

This paper gives a detailed analysis of nanotechnology's rising involvement in numerous surgical fields. We investigate the use of nanotechnology in orthopedic surgery, neurosurgery, plastic surgery, surgical oncology, heart surgery, vascular surgery, ophthalmic surgery, thoracic surgery, and minimally invasive surgery. The paper details how nanotechnology helps with arthroplasty, chondrogenesis, tissue regeneration, wound healing, and more. It also discusses the employment of nanomaterials in implant surfaces, bone grafting, and breast implants, among other things. The article also explores various nanotechnology uses, including stem cell-incorporated nano scaffolds, nano-surgery, hemostasis, nerve healing, nanorobots, and diagnostic applications. The ethical and safety implications of using nanotechnology in surgery are also addressed. The future possibilities of nanotechnology are investigated, pointing to a possible route for improved patient outcomes. The essay finishes with a comment on nanotechnology's transformational influence in surgical applications and its promise for future breakthroughs.

Ozonated saline intradermal injection: promising therapy for accelerated cutaneous wound healing in diabetic rats

Introduction

The use of ozonized water is gaining importance in medicine due to its effects on hyperglycemia and wound healing mechanisms.

Methods

This experiment was conducted to assess the impacts of intradermal administration of ozonated water on acute skin wound healing in a diabetic rat model. Sixty-four adult male Wistar rats were randomly divided into two groups: an ozonated water group (O3W) and a control group (CG). Experimental diabetes was chemically induced in the rats by the intraperitoneal administration of 60 mg/kg streptozotocin. One week later, full-thickness skin surgical wounds (1 cm2) were created between the two shoulders of the rats under general anesthesia. The wounds were then daily irrigated with normal saline (CG) or intradermally injected with 1 mL of ozonated water at 10 mg/L O3W. Wound healing was evaluated through macroscopic analysis, measuring wound size, diameter, and percentage of contraction rate before wounding and at 3, 7, 9, 12, 14, 18, 21, 24, and 28 days post-wounding. On days 7, 14, 21, and 28 after induction of the wounds, the body weights and blood glucose levels of rats (8 per group) were measured before the rats were euthanized. Moreover, the morphological structure of the tissue, vascular endothelial and transforming growth factor (VEGF and TGF) affinity and gene expression were examined.

Results

The O3W group had significantly lower blood glucose levels and wound size and gained body weight. Additionally, epithelial vascularization, stromal edema, TGF, and VEGF gene expression significantly improved in the O3W group.

Discussion

Therefore, ozonated water has the potential to enhance and promote cutaneous wound healing in diabetic rats.

Bioactive Glasses-Based Nanozymes Composite Macroporous Cryogel with Antioxidative, Antibacterial, and Pro-Healing Properties for Diabetic Infected Wound Repair

The treatment for diabetic ulcers still remains a big clinic challenge owing to the adverse repair microenvironment. Bioactive glasses (BGs) play an important role in the late stages of healing due to their ability to promote vascularization and collagen fiber deposition, but fail to improve infection and oxidative stress in the early stage.Therefore, it is critical to develop a material involved in regulating the whole healing phases. In this work, BGs-based nanozymes (MnO2 @PDA-BGs) with antioxidation, antibacterial and pro-healing abilities are synthesized by the redox deposition of MnO2 on mesoporous BGs. Afterward, cryogel with the interconnected macropore structure is fabricated by the polymerization of methacrylate anhydride gelatin (GelMA) at -20 °C. MnO2 @PDA-BGs are loaded into the cryogel to obtain nanocomposite cryogel (MnO2 @PDA-BGs/Gel) with multiple enzymes-like- activities to eliminate reactive oxygen species (ROS). Besides, MnO2 @PDA-BGs/Gel has intensive peroxidase-like activity under acidic condition and near infrared photothermal responsiveness to achieve excellent antibacterial performance. Cells experiments demonstrate that MnO2 @PDA-BGs/Gel recruits L929s and promotes their proliferation. Furthermore, MnO2 @PDA-BGs/Gel eliminates intracellular overexpressed ROS and maintains the viability of L929s. Animal experiments confirm that MnO2 @PDA-BGs/Gel promotes wound healing and avoided scarring by killing bacteria, reversing inflammation, promoting vascularization, and improving the deposition of collagen III.

Multifunctional Double-Layer and Dual Drug-Loaded Microneedle Patch Promotes Diabetic Wound Healing

Chronic nonhealing diabetic wounds are a serious complication of diabetes, with a high morbidity rate that can cause disability or death. The long period of inflammation and dysfunctional angiogenesis are the main reasons for wound-healing difficulty in diabetes. In this study, a multifunctional double-layer microneedle (DMN) is constructed to control infection and promote angiogenesis, meeting the multiple demands of the healing process of a diabetic wound. The double-layer microneedle is consisted in a hyaluronic acid substrate and a mixture of carboxymethyl chitosan and gelatin as the tip. The antibacterial drug tetracycline hydrochloride (TH) is loaded into the substrate of the microneedle to achieve rapid sterilization and promote resistance to external bacterial infections. The microneedle tip loaded with recombinant human epidermal growth factor (rh-EGF) is inserted into the skin, in response to gelatinase produced by resident microbe and disassociate to achieve the enzymatic response release. The double-layer drug-loaded microneedles (DMN@TH/rh-EGF) have antibacterial and antioxidant effects, and promote cell migration and angiogenesis in vitro. In an in vivo diabetic wound model, using rats, the DMN@TH/rh-EGF patch is able to inhibit inflammation, promote angiogenesis, collagen deposition, and tissue regeneration during the wound healing process, promoting its healing.

Multifunctional Hyaluronic Acid Microneedle Patch Embedded by Cerium/Zinc-Based Composites for Accelerating Diabetes Wound Healing

Chronic nonhealing diabetic wounds are becoming increasingly severe, with high rates of mortality and disability, owing to the difficulty in wound healing caused by hyperglycemia, blocked angiogenesis, biofilm infection, and excessive oxidative stress. A multicomponent enzyme-responsive natural polymer, a hyaluronic acid (HA) microneedle, embedded in a cerium/zinc-based nanomaterial (ZCO) for the treatment of diabetic wounds is reported. ZCO-HA can destroy the oxidation balance of bacteria, kill bacteria, and scavenge reactive oxygen species (ROS) to alleviate oxidative stress via the adjustable release of Zn2+ and Ce3+ /4+ . Additionally, ZCO-HA exhibits good anti-inflammatory activity through the nuclear factor kappa-B (NF-κB) pathway, which reduces the inflammatory state of macrophages and promotes cell proliferation, migration, and angiogenesis. In vitro experiments shows that ZCO-HA accompanies mouse fibroblast migration, promoting human umbilical vein endothelial cell tube formation. In vivo studies in mice with streptozotocin-induced (STZ)-induced diabetes reveal that this microneedle accelerates wound healing without systemic toxicity. RNA transcriptome sequencing illustrates that the multicomponent HA microneedle accelerates wound healing in diabetes through cell migration and inhibits inflammatory reactions and oxidative damage in mice via the NF-κB signaling pathway.

Red blood cell-mimicking liposomes loading curcumin promote diabetic wound healing

The excessive inflammatory response is known to be a major challenge for diabetic wound healing, while bacteria secreted toxin, α-hemolysin (Hlα), was recently reported to prolong inflammation and delay diabetic wound healing. In this study, we designed a red blood cell membrane (RBCM)-mimicking liposome containing curcumin (named RC-Lip) for the treatment of diabetic wounds. RC-Lips were successfully fabricated using the thin film dispersion method, and the fusion of RBC membrane with the liposomal membrane was confirmed via surface protein analysis. RC-Lips efficiently adsorbed Hlα, thereby reducing the damage and pro-apoptotic effects of Hlα on keratinocytes. Furthermore, they remarkably facilitated liposome uptake into macrophages with advanced curcumin release and regulation of M2 macrophage polarization. In a diabetic mouse and infected wound model, RC-Lips treatment significantly promoted wound healing and re-epithelialization while downregulating interleukin-1β (IL-1β) and upregulating interleukin-10 (IL-10). In summary, the results showed that the spongiform RC-Lips effectively modulate the inflammatory response after adsorbing Hlα and regulating M2 macrophage polarization, leading to a significant promotion of wound healing in diabetic mice. Hence, this study provides a prospective strategy of efficiently mediating inflammatory response for diabetic wounds.

Current status and progress in research on dressing management for diabetic foot ulcer

Diabetic foot ulcer (DFU) is a major complication of diabetes and is associated with a high risk of lower limb amputation and mortality. During their lifetime, 19%-34% of patients with diabetes can develop DFU. It is estimated that 61% of DFU become infected and 15% of those with DFU require amputation. Furthermore, developing a DFU increases the risk of mortality by 50%-68% at 5 years, higher than some cancers. Current standard management of DFU includes surgical debridement, the use of topical dressings and wound decompression, vascular assessment, and glycemic control. Among these methods, local treatment with dressings builds a protective physical barrier, maintains a moist environment, and drains the exudate from DFU wounds. This review summarizes the development, pathophysiology, and healing mechanisms of DFU. The latest research progress and the main application of dressings in laboratory and clinical stage are also summarized. The dressings discussed in this review include traditional dressings (gauze, oil yarn, traditional Chinese medicine, and others), basic dressings (hydrogel, hydrocolloid, sponge, foam, film agents, and others), bacteriostatic dressings, composite dressings (collagen, nanomaterials, chitosan dressings, and others), bioactive dressings (scaffold dressings with stem cells, decellularized wound matrix, autologous platelet enrichment plasma, and others), and dressings that use modern technology (3D bioprinting, photothermal effects, bioelectric dressings, microneedle dressings, smart bandages, orthopedic prosthetics and regenerative medicine). The dressing management challenges and limitations are also summarized. The purpose of this review is to help readers understand the pathogenesis and healing mechanism of DFU, help physicians select dressings correctly, provide an updated overview of the potential of biomaterials and devices and their application in DFU management, and provide ideas for further exploration and development of dressings. Proper use of dressings can promote DFU healing, reduce the cost of treating DFU, and reduce patient pain.

Hydrogel Bioelectronics for Health Monitoring

Hydrogels are considered an ideal platform for personalized healthcare due to their unique characteristics, such as their outstanding softness, appealing biocompatibility, excellent mechanical properties, etc. Owing to the high similarity between hydrogels and biological tissues, hydrogels have emerged as a promising material candidate for next generation bioelectronic interfaces. In this review, we discuss (i) the introduction of hydrogel and its traditional applications, (ii) the work principles of hydrogel in bioelectronics, (iii) the recent advances in hydrogel bioelectronics for health monitoring, and (iv) the outlook for future hydrogel bioelectronics' development.

Agar/gelatin hydro-film containing EGF and Aloe vera for effective wound healing

In the current study, we produced a hydro-film dressing for the treatment of chronic wounds. The hydro-film structure was composed of gelatin cross-linked with citric acid, agar and Aloe vera extract (AV); additionally epidermal growth factor (EGF) was loaded to promote wound healing. Due to the excellent hydrogel-forming ability of gelatin, the obtained hydro-film was able to swell 884 ± 36% of its dry weight, which could help controlling wound moisture. To improve gelatin mechanical properties, polymer chains were cross-linked with citric acid and agar, reaching an ultimate tensile strength that was in the highest range of human skin. In addition, it showed a slow degradation profile that resulted in a remaining weight of 28 ± 8% at day 28. Regarding, biological activity, the addition of AV and citric acid provided the ability to reduce human macrophage activation, which could help reverse the permanent inflammatory state of chronic wounds. Moreover, loaded EGF, together with the structural AV of the hydro-film, promoted human keratinocyte and fibroblast migration, respectively. Furthermore, the hydro-films presented excellent fibroblast adhesiveness, so they could be useful as provisional matrices for cell migration. Accordingly, these hydro-films showed suitable physicochemical characteristics and biological activity for chronic wound healing applications.

Functional carbohydrate-based hydrogels for diabetic wound therapy

Diabetes wound are grave and universal complications of diabetes. Owing to poor treatment course, high amputation rate and mortality, diabetes wound treatment and care have become a global challenge. Wound dressings have received much attention due to their ease of use, good therapeutic effect, and low costs. Among them, carbohydrate-based hydrogels with excellent biocompatibility are considered to be the best candidates for wound dressings. Based on this, we first systematically summarized the problems and healing mechanism of diabetes wounds. Next, common treatment methods and wound dressings were discussed, and the application of various carbohydrate-based hydrogels and their corresponding functionalization (antibacterial, antioxidant, autoxidation and bioactive substance delivery) in the treatment of diabetes wounds were emphatically introduced. Ultimately, the future development of carbohydrate-based hydrogel dressings was proposed. This review aims to provide a deeper understanding of wound treatment and theoretical support for the design of hydrogel dressings.

Interactive Skin Wound Segmentation Based on Feature Augment Networks

Skin wound segmentation in photographs allows non-invasive analysis of wounds that supports dermatological diagnosis and treatment. In this paper, we propose a novel feature augment network (FANet) to achieve automatic segmentation of skin wounds, and design an interactive feature augment network (IFANet) to provide interactive adjustment on the automatic segmentation results. The FANet contains the edge feature augment (EFA) module and the spatial relationship feature augment (SFA) module, which can make full use of the notable edge information and the spatial relationship information be-tween the wound and the skin. The IFANet, with FANet as the backbone, takes the user interactions and the initial result as inputs, and outputs the refined segmentation result. The pro-posed networks were tested on a dataset composed of miscellaneous skin wound images, and a public foot ulcer segmentation challenge dataset. The results indicate that the FANet gives good segmentation results while the IFANet can effectively improve them based on simple marking. Comprehensive comparative experiments show that our proposed networks outperform some other existing automatic or interactive segmentation methods, respectively.

Polymer-Based Wound Dressings Loaded with Ginsenoside Rg3

The skin, the largest organ in the human body, mainly plays a protective role. Once damaged, it can lead to acute or chronic wounds. Wound healing involves a series of complex physiological processes that require ideal wound dressings to promote it. The current wound dressings have characteristics such as high porosity and moderate water vapor permeability, but they are limited in antibacterial properties and cannot protect wounds from microbial infections, which can delay wound healing. In addition, several dressings contain antibiotics, which may have bad impacts on patients. Natural active substances have good biocompatibility; for example, ginsenoside Rg3 has anti-inflammatory, antibacterial, antioxidant, and other biological activities, which can effectively promote wound healing. Some researchers have developed various polymer wound dressings loaded with ginsenoside Rg3 that have good biocompatibility and can effectively promote wound healing and reduce scar formation. This article will focus on the application and mechanism of ginsenoside Rg3-loaded dressings in wounds.

Do Curdlan Hydrogels Improved with Bioactive Compounds from Hop Exhibit Beneficial Properties for Skin Wound Healing?

Chronic wounds, among others, are mainly characterized by prolonged inflammation associated with the overproduction of reactive oxygen species and pro-inflammatory cytokines by immune cells. As a consequence, this phenomenon hinders or even precludes the regeneration process. It is known that biomaterials composed of biopolymers can significantly promote the process of wound healing and regeneration. The aim of this study was to establish whether curdlan-based biomaterials modified with hop compounds can be considered as promising candidates for the promotion of skin wound healing. The resultant biomaterials were subjected to an evaluation of their structural, physicochemical, and biological in vitro and in vivo properties. The conducted physicochemical analyses confirmed the incorporation of bioactive compounds (crude extract or xanthohumol) into the curdlan matrix. It was found that the curdlan-based biomaterials improved with low concentrations of hop compounds possessing satisfactory hydrophilicity, wettability, porosity, and absorption capacities. In vitro, tests showed that these biomaterials were non-cytotoxic, did not inhibit the proliferation of skin fibroblasts, and had the ability to inhibit the production of pro-inflammatory interleukin-6 by human macrophages stimulated with lipopolysaccharide. Moreover, in vivo studies showed that these biomaterials were biocompatible and could promote the regeneration process after injury (study on Danio rerio larvae model). Thus, it is worth emphasizing that this is the first paper demonstrating that a biomaterial based on a natural biopolymer (curdlan) improved with hop compounds may have biomedical potential, especially in the context of skin wound healing and regeneration.