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

Micro-Gel Ensembles for Accelerated Healing of Chronic Wound via pH Regulation

The pH value in the wound milieu plays a key role in cellular processes and cell cycle processes involved in the process of wound healing. Here, a microfluidic assembly technique is employed to fabricate micro-gel ensembles that can precisely tune the pH value of wound surface and accelerate wound healing. The micro-gel ensembles consist of poly (hydroxypropyl acrylate-co-acrylic acid)-magnesium ions (poly-(HPA-co-AA)-Mg²⁺ ) gel and carboxymethyl chitosan (CMCS) gel, which can release and absorb hydrogen ion (H⁺ ) separately at different stages of healing in response to the evolution of wound microenvironment. By regulating the wound pH to affect the proliferation and migration of cell on the wound and the activity of various biological factors in the wound, the physiological processes are greatly facilitated which results in much accelerated healing of chronic wound. This work presents an effective strategy in designing wound healing materials with vast potentials for chronic wound management.

A smart hydrogel patch with high transparency, adhesiveness and hemostasis for all-round treatment and glucose monitoring of diabetic foot ulcers

The treatment and management of diabetic foot ulcers (DFUs) is a pretty intractable problem for clinical nursing. Urgently, the "Black Box" status of the healing process prevents surgeons from providing timely analysis for more effective diagnosis and therapy of the wound. Herein, we designed a transparent monitoring system to treat and manage the DFUs with blood oozing and hard-healing, which resolved the problem of blind management for the other conductive patches. This system was prepared from a conductive hydrogel patch with ultra-high transparence (up to 93.6%), adhesiveness and hemostasis, which is engineered by assembling in situ formed poly(tannic acid) (PTA)-doped polypyrrole (PPy) nanofibrils in the poly(acrylamide-acrylated adenine) (P(AM-Aa)) polymer networks. Significantly, the high transparent conductive hydrogel patch can monitor the wound-healing status visually and effectively promote the healing of DFUs by accelerating hemostasis, improving communication between cells, preventing wound infection, facilitating collagen deposition, and promoting angiogenesis. In addition, the versatile hydrogel patch could realize indirect blood glucose monitoring by detecting the glucose levels on wounds, and further sense the movements with different magnitudes of human body timely. This research may provide a novel strategy in the design of chronic wound dressings for monitoring and treating the wounds synergistically.

An Overview of Diabetic Foot Ulcers and Associated Problems with Special Emphasis on Treatments with Antimicrobials

One of the most significant challenges of diabetes health care is diabetic foot ulcers (DFU). DFUs are more challenging to cure, and this is particularly true for people who already have a compromised immune system. Pathogenic bacteria and fungi are becoming more resistant to antibiotics, so they may be unable to fight microbial infections at the wound site with the antibiotics we have now. This article discusses the dressings, topical antibacterial treatment, medications and debridement techniques used for DFU and provides a deep discussion of DFU and its associated problems. English-language publications on DFU were gathered from many different databases, such as Scopus, Web of Science, Science Direct, Springer Nature, and Google Scholar. For the treatment of DFU, a multidisciplinary approach involving the use of diagnostic equipment, skills, and experience is required. Preventing amputations starts with patient education and the implementation of new categorization systems. The microbiota involved in DFU can be better understood using novel diagnostic techniques, such as the 16S-ribosomal DNA sequence in bacteria. This could be achieved by using new biological and molecular treatments that have been shown to help prevent infections, to control local inflammation, and to improve the healing process.

Color-switchable and photoluminescent poly (vinyl chloride) for multifunctional smart applications

Recycled poly (vinyl chloride) (PVC) waste was used to prepare transparent material with long-lasting phosphorescence, photochromic activity, hydrophobicity, strong optical transmission, ultraviolet (UV) protection, and stiffness. Lanthanide-activated aluminate (LaA) microparticles were prepared via the high temperature solid state procedure, which were subjected to the top-down grinding technology to afford LaA nanoparticles (LaAN). Laminated poly (vinyl chloride) bottles were shredded into a transparent plastic matrix, which was combined with LaAN and drop-casted to produce smart materials for a variety of applications. Smart window and photochromic film for smart packaging can be made from recycled poly (vinyl chloride) waste by immobilizing it with various ratios of LaAN. Long-lasting phosphorescent translucent poly (vinyl chloride) smart window and films need LaAN to be evenly dispersed in PVC without clumping. Different analytical methods were employed to assess the materials' morphological structure and chemical composition. Photoluminescence and decay spectra were all employed to investigate the luminescence characteristics. In addition, the mechanical performance was studied. According to CIE Lab (Commission Internationale de L'éclairage) color measurements, this transparent PVC smart material becomes a bright green under UV rays and turns a greenish-yellow in the dark. The PVC luminescence was observed to exhibit an apparent emission bands at 429 and 513 nm when excited at 367 nm. Improvements have been monitored in the UV shielding and hydrophobicity with increasing the phosphor concentration. LaAN-immobilized PVC exhibited reversible photochromism. The present approach can be applied for a variety of applications, such as anticounterfeiting films for smart packaging, smart window, and warning lightening marks.

Microgel-integrated, high-strength in-situ formed hydrogel enables timely emergency trauma treatment

High-strength hydrogels formed in situ through a convenient gel transition process are highly desirable for emergency treatment due to their ability to quickly respond to accidents. However, current in-situ formed hydrogels require a laborious precursor preparation process or lack sufficient mechanical strength. Herein, we reported a series of microgels that were capable of convenient in-situ transition to high-strength hydrogels from their easily portable form, thereby facilitating emergency treatment. Three kinds of microgels were derived from two types of hydrogen bonds (H-bonds; OH⋯OC, NH⋯OC) crosslinked preformed hydrogels, and all exhibited excellent stability when stored at room temperature. After mixing with water, all these microgels could undergo a quick hydration process and then transform into high-strength hydrogels in situ through H-bonds. Specifically, stronger H-bond crosslinked microgels could build hydrogels with higher mechanical strength, albeit at the cost of longer hydration and operation time. Nevertheless, the whole operation process could be finished within several minutes, and the resultant hydrogels could exhibit maximally megapascal-level compressive strength and tens of kilopascal storage modulus. In the comparison of emergency application performance with commercial chitosan hemostatic powder (CHP), we found that the microgels could stop accidental bleeding almost immediately, and the whole process from taking out the stored microgels to hemostasis could be completed within 15 s, which was superior to CHP. Overall, the results indicated that the in-situ formed microgel-based hydrogels with convenient gel-transition ability and high strength showed great potential in emergency treatments.

Chitosan: A Sustainable Material for Multifarious Applications

Due to the versatility of its features and capabilities, chitosan generated from marine crustacean waste is gaining importance and appeal in a wide variety of applications. It was initially used in pharmaceutical and medical applications due to its antibacterial, biocompatible, and biodegradable properties. However, as the demand for innovative materials with environmentally benign properties has increased, the application range of chitosan has expanded, and it is now used in a variety of everyday applications. The most exciting aspect of the chitosan is its bactericidal properties against pathogens, which are prevalent in contaminated water and cause a variety of human ailments. Apart from antimicrobial and water filtration applications, chitosan is used in dentistry, in water filtration membranes to remove metal ions and some heavy metals from industrial effluents, in microbial fuel cell membranes, and in agriculture to maintain moisture in fruits and leaves. It is also used in skin care products and cosmetics as a moisturizer, in conjunction with fertilizer to boost plant immunity, and as a bi-adhesive for bonding woods and metals. As it has the capacity to increase the life span of food items and raw meat, it is an unavoidable component in food packing and preservation. The numerous applications of chitosan are reviewed in this brief study, as well as the approaches used to incorporate chitosan alongside traditional materials and its effect on the outputs.

ELECTROSPUN SODIUM ALGINATE/POLY(ETHYLENE OXIDE) NANOFIBERS FOR WOUND HEALING APPLICATIONS: CHALLENGES AND FUTURE DIRECTIONS

Alginate is an interesting natural biopolymer to be considered for biomedical applications due to its advantages and good biological properties. These biological properties make electrospun alginate nanofibers suitable for various uses in the biomedical field, such as wound healing dressings, drug delivery systems, or both. Unfortunately, the fabrication of alginate nanofibers by electrospinning is very challenging because of the high viscosity of the solution, high surface tension and rigidity in water due to hydrogen bonding, and also their diaxial linkages. This review presents an overview of the factors affecting the electrospinning process of sodium alginate/poly(ethylene oxide) (SA/PEO), the application of SA/PEO in drug delivery systems for wound healing applications, and the degradation and swelling properties of SA/PEO. The challenges and future directions of SA/PEO in the medical field are also discussed.

Exploration of Lipid-Based Nanocarriers as Drug Delivery Systems in Diabetic Foot Ulcer

Diabetes mellitus is a chronic manifestation characterized by high levels of glucose in the blood resulting in several complications including diabetic wounds and ulcers, which predominantly require a longer duration of treatment and adversely affect the quality of life of the patients. Nanotechnology-based therapeutics (both intrinsic and extrinsic types) have emerged as a promising treatment in diabetic foot ulcer/chronic wounds owing to their unique characteristics and specific functional properties. In this review, we have focused on the significance of the use of lipids in the healing of diabetic ulcers, their interaction with the injured skin, and recent trends in lipid-based nanocarriers for the healing of diabetic wounds. Lipid nanocarriers are also being investigated for gene therapy in diabetic wound healing to encapsulate nucleic acids such as siRNA and miRNA, which could silence the expression of inflammatory cytokines overexpressed in chronic wounds. Additionally, these are also being explored for encapsulating proteins, peptides, growth factors, and other biological genetic material as therapeutic agents. Lipid-based nanocarriers encompassing a wide variety of carriers such as liposomes, niosomes, ethosomes, solid lipid nanoparticles, and lipidoid nanoparticles that are explored for the treatment of foot ulcers supplemented with relevant research studies have been discussed in the present review. Lipid-based nanodrug delivery systems have demonstrated promising wound healing potential, particularly in diabetic conditions due to the enhanced efficacy of the entrapped active molecules.

Fabrication and evaluation of multifunctional agarose based electrospun scaffolds for cutaneous wound repairs

Despite several advances in chronic wound management, natural product based scaffolds with high exude absorption and mechanical strength are still a hotspot in the medical field. Thus, present study illustrates the fabrication of agarose (AG; 10% w/v)/polyvinyl alcohol 12% w/v) based multifunctional nanofibrous electrospun scaffolds. Zinc citrate (1%, 3% and 5% w/w of the polymer) was used as a potential antibacterial agent. The fabricated scaffolds exhibit a swelling of ∼550% in phosphate buffer saline and mechanical strength of 10.11 ± 0.31 MPa which is suitable for most of the wound healing applications that require high strength. In vitro study revealed an increased migration and proliferation of L929 fibroblasts with AG blends when compared to the control. The fabricated scaffolds exhibited antibacterial properties against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacterial strains. Hence, a multifunctional (ability to protect wounds from bacterial infections along with effective swelling and mechanical support), natural product based, eco-friendly scaffold to serve as a potential wound dressing material has been successfully fabricated.

Diabetic foot ulcer, antimicrobial remedies and emerging strategies for the treatment

According to the International Diabetes Federation's 2015 study, diabetes affects over 415 million people globally (5 million of whom die each year), and the incidence of diabetes is expected to climb to over 640 million (1 in 10) by 2040. (IDF 2015). Diabetes foot ulcers (DFU) are one of the most significant diabetic health consequences. Antimicrobial treatments, such as dressings, topical therapies, medicines, drugs, debridement procedures, molecular, cellular, and gene therapies, plant extracts, antimicrobial peptides, growth factors, devices, ozone, and energy-based therapies, would be the focus of this study. Scopus, Web of Science, Bentham Science, Science Direct, and Google Scholar were among the sources used to compile the English-language publications on DFU. DFU treatment requires a multidisciplinary approach that includes the use of proper diagnostic tools, competence, and experience. To prevent amputations, this starts with patient education and the use of new categories to steer treatment. New diagnostic methods, such as the 16S ribosomal DNA sequence in bacteria, should become available to acquire a better knowledge of the microbiota in DFUs. 

Responsive hydrogel-based microneedle dressing for diabetic wound healing

Wound healing is a critical challenge in diabetic patients, mainly due to long-term dysglycemia and its related pathological complications. Subcutaneous insulin injection represents a typical clinical solution, while the low controllability of insulin administration commonly leads to a result far from the optimal therapeutic effect. In this work, we developed a glucose-responsive insulin-releasing hydrogel for microneedle dressing fabrication and then investigated its effects on diabetic wound healing. The hydrogel system was composed of biocompatible gelatin methacrylate (GelMa), glucose-responsive monomer 4-(2-acrylamidoethylcarbamoyl)-3-fluorophenylboronic acid (AFPBA) and gluconic insulin (G-insulin), and the Gel-AFPBA-ins hydrogel-based microneedle dressing was developed by replicating PDMS molds. The resultant hydrogel microneedle dressing exhibited adequate mechanical properties, high biocompatibility, glucose-responsive insulin release behavior upon exposure to different glucose solutions, and potent adhesion to the skin compared to hydrogels without microstructures. The microneedle dressing could accelerate the diabetic wound healing process with decreased inflammatory reaction, enhanced collagen deposition on the regenerated tissue sites, and improved blood glucose control in animals. Therefore, the glucose-responsive insulin-releasing hydrogel microneedle dressing is effective in diabetic wound management and has potential for treatment of other chronic skin injuries.

A multifunctional 3D dressing unit based on the core-shell hydrogel microfiber for diabetic foot wound healing

The healing mechanism of diabetic foot wounds is very complicated, and it is difficult for a single-function medical dressing to achieve good therapeutic effects. We propose a simple coaxial biological 3D printing technology, which uses one-step 3D deposition to continuously produce multifunctional medical dressings on the basis of core-shell hydrogel fibers. These dressings have good biocompatibility, controlled drug-release performance, excellent water absorption and retention, and antibacterial and anti-inflammatory functions. In vivo experiments with type 2 diabetic rats were performed over a 14-day period to compare the performance of the multifunctional 3D dressing with a gauze control; the multifunctional 3D dressing reduced inflammation, effectively increased the post-healing thickness of granulation tissue, and promoted the formation of blood vessels, hair follicles, and highly oriented collagen fiber networks. Therefore, the proposed multifunctional dressing is expected to be suitable for clinical applications for healing diabetic foot wounds.

Synthesis of Poly(acrylic acid)-Cysteine-Based Hydrogels with Highly Customizable Mechanical Properties for Advanced Cell Culture Applications

The fabrication of highly customizable scaffolds is a key enabling technology in the development of predictive in vitro cell models for applications in drug discovery, cancer research, and regenerative medicine. Naturally derived and synthetic hydrogels are good candidates for in vitro cell growth studies, owing to their soft and biocompatible nature; however, they are often hindered by limited ranges of stiffness and the requirement to modify the gel with additional extracellular matrix (ECM) proteins for cell adherence. Here, we report on the synthesis of a printable synthetic hydrogel based on cysteine-modified poly(acrylic acid) (PAA-Cys) with tuneable mechanical and swelling properties by incorporating acrylic acid into the PAA-Cys network and subsequent photoinitiated thiol-acrylate cross-linking. Control of the acrylic acid concentration and UV curing time produces a series of hydrogels with swelling ratios in excess of 100% and Young's modulus values ranging from ∼2 to ∼35 kPa, of which most soft tissues fall within. Biocompatibility studies with RPE1 cells showed excellent cell adhesion and cell viability without the need for further modification with ECM proteins, but still can be modified as needed. The versatility of the hydrogel tuneable properties is demonstrated by culturing with RPE1 cells, which in vivo perform an important function in the visual process and the dysfunction of which may lead to various retinal abnormalities, such as glaucoma.

Advancement in Nanoformulations for the Management of Diabetic Wound Healing

People with diabetes have a very slow tendency for wound healing. Wound healing is a vast process where several factors inhibit the sequence of healing. Nano formulation plays a major role during acute and chronic wound healing. The present manuscript aims to discuss the role of nanoformulation in the treatment of diabetic wound healing. Diabetes is a common disease that has harmful consequences which lead to bad health. During the literature survey, it was observed that nanotechnology has significant advantages in the treatment of diabetic wound healing. The present manuscript summarized the role of nanomaterials in wound healing, challenges in diabetic wound healing, physiology of wound healing, a limitation that comes during wound repair, and treatments available for wound healing. After a comprehensive literature survey, it can be concluded that health worker needs more focus on the area of wound healing in diabetic patients. Medical practitioners, pharmaceutical and biomedical researchers need more attention towards the utilization of nanoformulations for the treatment of wound healing, specifically in the case of diabetes.

A Guanosine-Quadruplex Hydrogel as Cascade Reaction Container Consuming Endogenous Glucose for Infected Wound Treatment-A Study in Diabetic Mice

Diabetic foot ulcers infected with antibiotic-resistant bacteria form a severe complication of diabetes. Antimicrobial-loaded hydrogels are used as a dressing for infected wounds, but the ongoing rise in the number of antimicrobial-resistant infections necessitates new, nonantibiotic based designs. Here, a guanosine-quadruplex (G4 )-hydrogel composed of guanosine, 2-formylphenylboronic acid, and putrescine is designed and used as a cascade-reaction container. The G4 -hydrogel is loaded with glucose-oxidase and hemin. The first cascade-reaction, initiated by glucose-oxidase, transforms glucose and O2  into gluconic acid and H2 O2 . In vitro, this reaction is most influential on killing Staphylococcus aureus or Pseudomonas aeruginosa in suspension, but showed limited killing of bacteria in biofilm-modes of growth. The second cascade-reaction, however, transforming H2 O2  into reactive-oxygen-species (ROS), also enhances killing of biofilm bacteria due to hemin penetration into biofilms and interaction with eDNA G-quadruplexes in the biofilm matrix. Therewith, the second cascade-reaction generates ROS close to the target bacteria, facilitating killing despite the short life-time of ROS. Healing of infected wounds in diabetic mice proceeds faster upon coverage by these G4 -hydrogels than by clinically common ciprofloxacin irrigation. Moreover, local glucose concentrations around infected wounds decrease. Concluding, a G4 -hydrogel loaded with glucose-oxidase and hemin is a good candidate for infected wound dressings, particularly in diabetic patients.

The safety and efficacy of mesenchymal stem cell therapy in diabetic lower extremity vascular disease: a meta-analysis and systematic review

BACKGROUND AIMS

Several studies have shown the efficacy of mesenchymal stem cell (MSC) therapy for lower extremity vascular disease (LEVD) in diabetic patients, but the results are not consistent. Therefore, the authors conducted a meta-analysis of randomized controlled trials (RCTs) to examine the safety and efficacy of MSC therapy in diabetic patients with LEVD.

METHODS

Eight available databases were searched in both English and Chinese to identify RCTs comparing MSC therapy-based conventional treatment with conventional treatment alone in diabetic patients with LEVD. Three investigators independently screened the literature, extracted the data and assessed the risk bias. Meta-analysis was performed using RevMan 5.4.1 and Stata 14.0.

RESULTS

A total of 10 studies involving 453 patients were included. Compared with conventional treatment only, patients receiving MSC therapy-based conventional treatment had a higher ulcer healing rate, greater number of reduced ulcers and shorter complete healing time. MSC therapy also increased ankle-brachial index and transcutaneous oxygen pressure. In addition, four of the included studies showed that MSC therapy significantly improved the number of new collateral vessels. Moreover, no more adverse events were recorded in the MSC group.

CONCLUSIONS

This meta-analysis suggests that MSC therapy promotes ulcer healing in diabetic LEVD patients with ulcers, improves blood supply and has a favorable safety profile. More large and well-designed RCTs with long-term follow-up are still needed to explore the safety and efficacy of MSC therapy in diabetic patients with LEVD.

Evaluation of a Multifunctional Polyvinylpyrrolidone/Hyaluronic Acid-Based Bilayer Film Patch with Anti-Inflammatory Properties as an Enhancer of the Wound Healing Process

The management of acute and chronic wounds is still a socioeconomic burden for society due to the lack of suitable tools capable of supporting all the healing phases. The exponential spread of diabetes worldwide and the consequent increase of complicated diabetic ulcers require further efforts to develop scalable, low-cost, and easy-to-use treatments for tackling this emergency. Recently, we explored the fabrication of a polyvinylpyrrolidone/hyaluronic acid-based bilayer wound dressing, characterizing its physicochemical features and detailing its excellent antimicrobial activity. Here, we further demonstrate its biocompatibility on fibroblasts, keratinocytes, and red blood cells. The bilayer shows anti-inflammatory properties, statistically reducing the level of IL-6, IL-1β, and TNF-α, and a capacity to accelerate wound healing in vitro and in healthy and diabetic mice models compared to untreated mice. The outcomes suggest that this bilayer material can be an effective tool for managing different skin injuries.

Nanomaterials for application in wound Healing: current state-of-the-art and future perspectives

Nanoparticles are the gateway to the new era in drug delivery of biocompatible agents. Several products have emerged from nanomaterials in quest of developing practical wound healing dressings that are nonantigenic, antishear stress, and gas-exchange permeable. Numerous studies have isolated and characterised various wound healing nanomaterials and nanoproducts. The electrospinning of natural and synthetic materials produces fine products that can be mixed with other wound healing medications and herbs. Various produced nanomaterials are highly influential in wound healing experimental models and can be used commercially as well. This article reviewed the current state-of-the-art and briefly specified the future concerns regarding the different systems of nanomaterials in wound healing (i.e., inorganic nanomaterials, organic and hybrid nanomaterials, and nanofibers). This review may be a comprehensive guidance to help health care professionals identify the proper wound healing materials to avoid the usual wound complications.

Polymer-Based Wound Dressing Materials Loaded with Bioactive Agents: Potential Materials for the Treatment of Diabetic Wounds

Diabetic wounds are severe injuries that are common in patients that suffer from diabetes. Most of the presently employed wound dressing scaffolds are inappropriate for treating diabetic wounds. Improper treatment of diabetic wounds usually results in amputations. The shortcomings that are related to the currently used wound dressings include poor antimicrobial properties, inability to provide moisture, weak mechanical features, poor biodegradability, and biocompatibility, etc. To overcome the poor mechanical properties, polymer-based wound dressings have been designed from the combination of biopolymers (natural polymers) (e.g., chitosan, alginate, cellulose, chitin, gelatin, etc.) and synthetic polymers (e.g., poly (vinyl alcohol), poly (lactic-co-glycolic acid), polylactide, poly-glycolic acid, polyurethanes, etc.) to produce effective hybrid scaffolds for wound management. The loading of bioactive agents or drugs into polymer-based wound dressings can result in improved therapeutic outcomes such as good antibacterial or antioxidant activity when used in the treatment of diabetic wounds. Based on the outstanding performance of polymer-based wound dressings on diabetic wounds in the pre-clinical experiments, the in vivo and in vitro therapeutic results of the wound dressing materials on the diabetic wound are hereby reviewed.

Recent Advances on Bacterial Cellulose-Based Wound Management: Promises and Challenges

Wound healing is a therapeutic challenge due to the complexity of the wound. Various wounds could cause severe physiological trauma and bring social and economic burdens to the patient. The conventional wound healing treatments using bandages and gauze are limited particularly due to their susceptibility to infection. Different types of wound dressing have developed in different physical forms such as sponges, hydrocolloids, films, membranes, and hydrogels. Each of these formulations possesses distinct characteristics making them appropriate for the treatment of a specific wound. In this review, the pathology and microbiology of wounds are introduced. Then, the most recent progress on bacterial cellulose- (BC-) based wound dressing discussed and highlighted their antibacterial and reepithelization properties in vitro and in vivo wound closure. Finally, the challenges and future perspectives on the development of BC-based wound dressing biomaterials are outlined.

Bioactive Chitosan-Based Organometallic Scaffolds for Tissue Engineering and Regeneration

Captivating achievements in developing advanced hybrid biostructures through integrating natural biopolymers with inorganic materials (e.g., metals and metalloids) have paved the way towards the application of bioactive organometallic scaffolds (OMSs) in tissue engineering and regenerative medicine (TERM). Of various biopolymers, chitosan (CS) has been used widely for the development of bioactive OMSs, in large part due to its unique characteristics (e.g., biocompatibility, biodegradability, surface chemistry, and functionalization potential). In integration with inorganic elements, CS has been used to engineer advanced biomimetic matrices to accommodate both embedded cells and drug molecules and serve as scaffolds in TERM. The use of the CS-based OMSs is envisioned to provide a new pragmatic potential in TERM and even in precision medicine. In this review, we aim to elaborate on recent achievements in a variety of CS/metal, CS/metalloid hybrid scaffolds, and discuss their applications in TERM. We also provide comprehensive insights into the formulation, surface modification, characterization, biocompatibility, and cytotoxicity of different types of CS-based OMSs.

Multifunctional Biomimetic Nanofibrous Scaffold Loaded with Asiaticoside for Rapid Diabetic Wound Healing

Diabetes mellitus is a chronic disease with a high mortality rate and many complications. A non-healing diabetic foot ulcer (DFU) is one the most serious complications, leading to lower-extremity amputation in 15% of diabetic patients. Nanofibers are emerging as versatile wound dressing due to their unique wound healing properties, such as a high surface area to volume ratio, porosity, and ability to maintain a moist wound environment capable of delivering sustained drug release and oxygen supply to a wound. The present study was aimed to prepare and evaluate a polyvinyl alcohol (PVA)–sodium alginate (SA)–silk fibroin (SF)-based multifunctional nanofibrous scaffold loaded with asiaticoside (AT) in diabetic rats. The SEM findings showed that fibers’ diameters ranged from 100–200 nm, and tensile strengths ranged from 12.41–16.80 MPa. The crosslinked nanofibers were sustained AT over an extended period. The MTT and scratch assay on HaCat cells confirmed low cytotoxicity and significant cell migration, respectively. Antimicrobial tests revealed an excellent anti-microbial efficacy against P. aeruginosa and S. aureus bacteria. In-vivo study demonstrated better wound healing efficacy in diabetic rats. In addition, the histopathological studies showed its ability to restore the normal structure of the skin. The present study concluded that developed multifunctional nanofibers have a great potential for diabetic wound healing applications.

Nanofiber Systems as Herbal Bioactive Compounds Carriers: Current Applications in Healthcare

Nanofibers have emerged as a potential novel platform due to their physicochemical properties for healthcare applications. Nanofibers’ advantages rely on their high specific surface-area-to-volume and highly porous mesh. Their peculiar assembly allows cell accommodation, nutrient infiltration, gas exchange, waste excretion, high drug release rate, and stable structure. This review provided comprehensive information on the design and development of natural-based polymer nanofibers with the incorporation of herbal medicines for the treatment of common diseases and their in vivo studies. Natural and synthetic polymers have been widely used for the fabrication of nanofibers capable of mimicking extracellular matrix structure. Among them, natural polymers are preferred because of their biocompatibility, biodegradability, and similarity with extracellular matrix proteins. Herbal bioactive compounds from natural extracts have raised special interest due to their prominent beneficial properties in healthcare. Nanofiber properties allow these systems to serve as bioactive compound carriers to generate functional matrices with antimicrobial, anti-inflammatory, antioxidant, antiseptic, anti-viral, and other properties which have been studied in vitro and in vivo, mostly to prove their wound healing capacity and anti-inflammation properties.

A review on Biopolymer-derived Electrospun Nanofibers for Biomedical and Antiviral Applications

Unique aspects of polymer-derived nanofibers provide significant potential in the area of biomedical and health care applications. Much research has demonstrated several plausible nanofibers to overcome the modern-day challenges in...

Improvement of Skin Wound Healing for Diabetic Mice with Thermosensitive Hydrogel Combined with Insulin Injection

Chronic skin wound caused by diabetic disease is very common worldwide. Moreover, there is a shortage of effective curing technology in clinic. In this work, we developed a novel technology using thermosensitive hydrogel on wound top combined with insulin injection. The efficiency and mechanism of this technology were investigated in a diabetic mouse model. Dorsal-paired 8-10 mm diameter wounds were created in 12 mice. The wound healing rate was determined over a 28-day interval in healthy control (Control), control with diabetes (DControl), poloxamer treatment (Pox), and poloxamer plus insulin injection (Poxin) mice. Histological specimens were observed in all samples. Real-time quantitative polymerase chain reaction (qRT-PCR) was performed to measure the relative expression of α-smooth muscle actin (α-SMA) and transforming growth factor beta 1 (TGF-β1) in wound tissues at 7, 14, and 28 days. Compared with DControl animals, those treated with Poxin showed accelerated wound closure and healing rate (p < 0.05); expression of both α-SMA and TGF-β1 was significantly higher than that of the DControl and Pox animals during the first 7 days postoperation, but a significant decrease at day 14. Therefore, we concluded that hydrogel combined with insulin accelerated wound healing. Controlling the glucose level via insulin injection is more beneficial than hydrogel alone for healing chronic wounds, potentially through the increase of α-SMA and TGF-β1 expression in early phase.

Stress-Reducing Psychological Interventions as Adjuvant Therapies for Diabetic Chronic Wounds

BACKGROUND

Diabetic foot ulcers (DFUs) are a major complication of diabetes mellitus and a leading cause of lower limb amputation. Interventions to reduce psychological stress may have the potential to improve self-care and greatly reduce the morbidity and mortality associated with DFU. This review is focused on the consequences of psychological stress in wound healing and reflects on the effects of currently used psychological stress-reducing interventions in patients with DFU, proposing new applications for currently used stress-reduction interventions.

RESULTS

Stress is a natural and fundamental survival mechanism that becomes harmful when chronic. DFU is associated with high levels of anxiety and chronic psychological stress. Chronic stressinduced cortisol and adrenaline release impair wound healing, independently of the stressor. Psychological stress-reducing interventions, such as relaxation with guided imagery, biofeedback-assisted relaxation, mindfulness-based strategies, and hypnosis, can lead to a reduction in perceived stress and improve wound healing by reducing wound inflammation and pain while improving glycemic control. All stress reduction interventions also lead to pain relief and improved patient's quality of life.

CONCLUSION

Psychological stress-reducing interventions are promising adjuvant therapies for DFU. Their clinical application can improve self-care by tackling patient's expectations, anxieties, and fears. They can also help patients manage stress and pain while reducing wound inflammation and improving wound healing.

Bio-fabricated nanocomposite hydrogel with ROS scavenging and local oxygenation accelerates diabetic wounds healing

Chronic wounds, especially diabetic wounds, have been suffering from abnormal long inflammatory periods due to their pathological microenvironment of high reactive oxygen species (ROS) level and lack of blood vessels....

Advances in Modified Hyaluronic Acid-Based Hydrogels for Skin Wound Healing

Hyaluronic acid (HA) is a natural linear anionic polysaccharide with many unique characteristics such as excellent biocompatibility and biodegradability, native biofunctionality, hydrophilicity, and non-immunoreactivity. HA plays crucial roles in numerous...

The Topical Hemostatic Materials for Coagulopathy

Medical sciences have witnessed significant progresses in hemostatic materials which have saved lives by supporting natural hemostatic ability. However, for the treatment of coagulopathy, where natural hemostatic ability is dysfunctional,...

A Polyaniline Nanoparticles Crosslinked Hydrogel with Excellent Photothermal Antibacterial and Mechanical Properties for Wound Dressing

Antibacterial hydrogel wound dressing is highly desirable in wound healing and infection control. However, the development of antibacterial hydrogels with controllable antibacterial properties and adequate mechanical properties without bacterial resistance and potential toxicity remains a challenge. Herein, a double bonds-ended polyaniline nanoparticle (Me-PANI NP) is synthesized, which can convert light energy into heat upon near-infrared (NIR) irradiation, and it is used as a novel photothermal antibacterial agent. The obtained bonds-ended Me-PANI NPs are subsequently involved in polyacrylamide (PAM) polymerization and served as chemical crosslinking points to form the Me-PANI NPs@PAM hydrogel, endowing the hydrogel with controllable photothermal antibacterial abilities upon NIR irradiation without time and space limit. Importantly, due to the energy dissipation of Me-PANI NPs under stretch, the Me-PANI NPs@PAM hydrogel achieves a maximum stretching ratio of 400% mechanical flexibility. The developed hydrogel can be potentially applied as a novel wound dressing to realize controllable treatment of bacterial infections and accelerate skin wound healing.

Oxygen-Releasing Composites: A Promising Approach in the Management of Diabetic Foot Ulcers

In diabetes, lower extremity amputation (LEA) is an irreversible diabetic-related complication that easily occurs in patients with diabetic foot ulcers (DFUs). Because DFUs are a clinical outcome of different causes including peripheral hypoxia and diabetic foot infection (DFI), conventional wound dressing materials are often insufficient for supporting the normal wound healing potential in the ulcers. Advanced wound dressing development has recently focused on natural or biocompatible scaffolds or incorporating bioactive molecules. This review directs attention to the potential of oxygenation of diabetic wounds and highlights current fabrication techniques for oxygen-releasing composites and their medical applications. Based on different oxygen-releasable compounds such as liquid peroxides and solid peroxides, for example, a variety of oxygen-releasing composites have been fabricated and evaluated for medical applications. This review provides the challenges and limitations of utilizing current oxygen releasable compounds and provides perspectives on advancing oxygen releasing composites for diabetic-related wounds associated with DFUs.

An Overview of Cellulose Derivatives-Based Dressings for Wound-Healing Management

Presently, notwithstanding the progress regarding wound-healing management, the treatment of the majority of skin lesions still represents a serious challenge for biomedical and pharmaceutical industries. Thus, the attention of the researchers has turned to the development of novel materials based on cellulose derivatives. Cellulose derivatives are semi-synthetic biopolymers, which exhibit high solubility in water and represent an advantageous alternative to water-insoluble cellulose. These biopolymers possess excellent properties, such as biocompatibility, biodegradability, sustainability, non-toxicity, non-immunogenicity, thermo-gelling behavior, mechanical strength, abundance, low costs, antibacterial effect, and high hydrophilicity. They have an efficient ability to absorb and retain a large quantity of wound exudates in the interstitial sites of their networks and can maintain optimal local moisture. Cellulose derivatives also represent a proper scaffold to incorporate various bioactive agents with beneficial therapeutic effects on skin tissue restoration. Due to these suitable and versatile characteristics, cellulose derivatives are attractive and captivating materials for wound-healing applications. This review presents an extensive overview of recent research regarding promising cellulose derivatives-based materials for the development of multiple biomedical and pharmaceutical applications, such as wound dressings, drug delivery devices, and tissue engineering.

Nanotechnology-based therapeutic applications: in vitro and in vivo clinical studies for diabetic wound healing

Diabetic wounds often indicate chronic complications that are difficult to treat. Unfortunately, existing conventional treatment modalities often cause unpremeditated side effects, given the need to develop alternative therapeutic phenotypes that are safe or have minimal side effects and risks. Nanotechnology-based platforms, including nanotherapeutics, nanoparticles (NPs), nanofibers, nanohydrogels, and nanoscaffolds, have garnered attention for their groundbreaking potential to decipher the biological environment and offer personalized treatment methods for wound healing. These nanotechnology-based platforms can successfully overcome the impediments posed by drug toxicity, existing treatment modalities, and the physiology and complexity of the wound sites. Furthermore, studies have shown that they play an essential role in influencing angiogenesis, collagen production, and extracellular matrix (ECM) synthesis, which are integral in skin repair mechanisms. In this review, we emphasized the importance of various nanotechnology-based platforms for healing diabetic wounds and report on the innovative preclinical and clinical outcomes of different nanotechnology-based platforms. This review also outlined the limitations of existing conventional treatment modalities and summarized the physiology of acute and chronic diabetic wounds.

Preparation and characterization of succinyl chitosan and succinyl chitosan nanoparticle film: In vitro and in vivo evaluation of wound healing activity

Development of novel wound dressing materials having the ability to prevent bacterial infections and capable of accelerating the tissue regeneration process is utmost important, since the wounds in patients can cause severe health issues. In the present work, we synthesized novel N-succinyl chitosan nanoparticles (N-SuC NPs) films and tested their antimicrobial, cytotoxicity, and in vitro and in vivo wound healing activity. N-SuC NPs were synthesized by ionic gelation method, and subsequently N-SuC NPs films were prepared by solution casting method using synthesized N-SuC NPs. The prepared N-SuC NPs films showed significant antimicrobial activity against Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration of 6 mg/mL and <8 mg/mL, respectively. The biocompatibility and the in vitro wound healing activity of N-SuC NPs films were analyzed using human dermal fibroblast (HDF) cells. In vivo cutaneous wound healing of the N-SuC NPs film was investigated using the Wister rat model, and the studies showed that the N-SuC NPs film significantly accelerated the wound healing process by inducing more blood vessels formation and tissue granulation. The experimental results showed that synthesized N-SuC NPs film had excellent antimicrobial, cytotoxicity and wound healing activity, indicating that it could be used in biomedical applications.

Deacetylated cellulose acetate nanofibrous dressing loaded with chitosan/propolis nanoparticles for the effective treatment of burn wounds

Every year, about 1 out of 9 get burnt in Egypt, with a mortality rate of 37%, and they suffer from physical disfigurement and trauma. For the treatment of second-degree burns, we aim at making a smart bandage provided with control of drug release (using chitosan nanoparticles) to enhance the healing process. This bandage is composed of natural materials; namely, cellulose acetate (CA), chitosan, and propolis (bee resin) as the loaded drug. Cellulose acetate nanofibers were deacetylated by NaOH after optimizing the reaction time and the concentration of NaOH solution, and the product was confirmed with FTIR analysis. Chitosan/propolis nanoparticles were prepared by ion gelation method with size ranging from 100 to 200 nm and a polydispersity index of 0.3. Chitosan/propolis nanoparticles were preloaded in the CA solution to ensure homogeneity. Loaded deacetylated cellulose nanofibers have shown the highest hydrophobicity measured by contact angle. Cytotoxicity of propolis and chitosan/propolis nanoparticles were tested and the experimental IC₅₀ value was about 137.5 and 116.0 μg/mL, respectively, with p-value ≤0.001. In addition, chitosan/propolis nanoparticles loaded into cellulose nanofibers showed a cell viability of 89.46% in the cell viability test. In-vivo experiments showed that after 21 days of treatment with the loaded nanofibers repairing of epithelial cells, hair follicles and sebaceous glands in the skin of the burn wound were found in albino-mice model.

MiR-770-5p, miR-661 and miR-571 expression level in serum and tissue samples of foot ulcer caused by diabetes mellitus type II in Iranian population

BACKGROUND

Microvascular complications related to diabetes mellitus type II such as foot ulcers are the reason of many mortalities among T2DM patients. The role of microRNAs (miRNAs, miRs) as potent regulators of gene expression is studied in different diseases such as diabetes mellitus and primary studies revealed their importance as early detecting biomarkers. Therefore, in this study it is tried to evaluate the expression level of some miRNAs (miR-770-5p, miR-661 and miR-571) in serum and tissue samples of T2DM related foot ulcer among Iranian patients.

METHODS

30 samples of blood and 30 muscle tissue were collected from T2DM patients suffering foot ulcer (T2DM + FU), 30 blood samples collected from T2DM patients without foot ulcer (T2DM-FU). 30 tissue samples collected from patients with trauma and 30 blood samples were selected as healthy controls.

RESULTS

The three studied miRNAs were statistically significant in all groups in comparison to control blood group. Also, comparison between other groups showed a significant increase of all studied miRNAs especially in the blood and tissues of T2DM + FU patients. The only significant correlation detected between the FBS level and miR-571 expression pattern in blood samples of T2DM + FU group. Finally, the results showed that miR-571, -661, and -770 has a statistically significant discriminative character for differentiating T2DM + FU patients from T2DM-FU both in tissue and blood samples.

CONCLUSION

Although more studies are essential for certifying these findings, our results showed that miR-770-5p, miR-661 and miR-571 are correlated with the microvascular complications related with T2DM such as foot ulcer.

Using type III recombinant human collagen to construct a series of highly porous scaffolds for tissue regeneration

As an alternative biopolymer material without the risks of the use of animal-derived collagens in soft tissue engineering applications, recombinant human collagen polypeptide (RHC) was used to construct three-dimensional porous scaffolds. RHC and RHC-chitosan (RHC-CHI) porous scaffolds were fabricated using a freeze-drying method to create highly porous internal structures and then cross-linked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). All scaffolds had interconnected porous structures with high porosity (90%), and pore size that ranged from 111 µm to 159 µm. The swelling ability and in vitro degradation of the prepared scaffolds were investigated. The mechanical properties could be tailored to meet the requirements of end-use application by adjusting the concentrations of the polymer or cross-linking agent, and the resulting mechanical strengths were comparable to those of biological soft tissues. The cytocompatibility of the fabricated porous scaffolds was investigated by seeding 3T3 fibroblasts into the porous structures, and then cell proliferation, distribution, morphology, and synthesis of extra cellular matrix-associated proteins were assessed. The results indicated that RHC-based porous scaffolds were non-cytotoxic and promoted the attachment and proliferation of the seeded cells. Finally, the in vivo study proved these porous scaffolds were able to accelerate the cell infiltration and collagen deposition that promoted the wound closure. Overall, the results indicate that RHC-based porous scaffolds show promise for use in soft tissue engineering due to their excellent in vitro cytocompatibility and adjustable mechanical properties.

Rational Design of Immunomodulatory Hydrogels for Chronic Wound Healing

With all the advances in tissue engineering for construction of fully functional skin tissue, complete regeneration of chronic wounds is still challenging. Since immune reaction to the tissue damage is critical in regulating both the quality and duration of chronic wound healing cascade, strategies to modulate the immune system are of importance. Generally, in response to an injury, macrophages switch from pro-inflammatory to an anti-inflammatory phenotype. Therefore, controlling macrophages' polarization has become an appealing approach in regenerative medicine. Recently, hydrogels-based constructs, incorporated with various cellular and molecular signals, have been developed and utilized to adjust immune cell functions in various stages of wound healing. Here, the current state of knowledge on immune cell functions during skin tissue regeneration is first discussed. Recent advanced technologies used to design immunomodulatory hydrogels for controlling macrophages' polarization are then summarized. Rational design of hydrogels for providing controlled immune stimulation via hydrogel chemistry and surface modification, as well as incorporation of cell and molecules, are also dicussed. In addition, the effects of hydrogels' properties on immunogenic features and the wound healing process are summarized. Finally, future directions and upcoming research strategies to control immune responses during chronic wound healing are highlighted.

Polymer-Based Nanotherapeutics for Burn Wounds

Burn wounds are complex and intricate injuries that have become a common cause of trauma leading to significant mortality and morbidity every year. Dressings are applied to burn wounds with the aim of promoting wound healing, preventing burn infection and restoring skin function. The dressing protects the injury and contributes to recovery of dermal and epidermal tissues. Polymer-based nanotherapeutics are increasingly being exploited as burn wound dressings. Natural polymers such as cellulose, chitin, alginate, collagen, gelatin and synthetic polymers like poly (lactic-co-glycolic acid), polycaprolactone, polyethylene glycol, and polyvinyl alcohol are being obtained as nanofibers by nanotechnological approaches like electrospinning and have shown wound healing and re-epithelialization properties. Their biocompatibility, biodegradability, sound mechanical properties and unique structures provide optimal microenvironment for cell proliferation, differentiation, and migration contributing to burn wound healing. The polymeric nanofibers mimic collagen fibers present in extracellular matrix and their high porosity and surface area to volume ratio enable increased interaction and sustained release of therapeutics at the site of thermal injury. This review is an attempt to compile all recent advances in the use of polymer-based nanotherapeutics for burn wounds. The various natural and synthetic polymers used have been discussed comprehensively and approaches being employed have been reported. With immense research effort that is currently being invested in this field and development of proper characterization and regulatory framework, future progress in burn treatment is expected to occur. Moreover, appropriate preclinical and clinical research will provide evidence for the great potential that polymer-based nanotherapeutics hold in the management of burn wounds.

Preparation of Foam Dressings Based on Gelatin, Hyaluronic Acid, and Carboxymethyl Chitosan Containing Fibroblast Growth Factor-7 for Dermal Regeneration

Wound recovery close to the function of the native skin is the goal of wound healing. In this study, we prepared foam dressings (FDs; 2-GHC-FD-1-9, 5-GHC-FD-1-9, and 10-GHC-FD-1-9) composed of various concentrations of gelatin, hyaluronic acid, and carboxymethyl chitosan, which are chemically interconnected through amide bond formation, for evaluating wound healing. Tensile and cell proliferation tests showed that 2-GHC-FD-1-9 are suitable for wound dressing. For further evaluation, three types of FDs, 2-GHC-FD-1, 2-GHC-FD-4, and 2-GHC-FD-8 were chosen. The results of animal intradermal reactivity, water vapor transmission rate, and absorption rate of the three FDs indicated that 2-GHC-FD-8 is the most appropriate scaffold for wound healing. For wound healing acceleration, various concentrations of fibroblast growth factor-7 (FGF-7) was soaked in 2-GHC-FD-8 (2-GHC-FD-8/F1-6) and evaluated by using scanning electron microscopy, cell proliferation, release behavior, and in vivo animal tests. The FDs showed interconnected porous structures, increased cell proliferation until 8.0 × 10-11 M, controlled release with initial burst within 1 h, and sustained release for 48 h. The results of the animal test showed an appropriate concentration of FGF-7 for wound healing. In addition, 2-GHC-FD-8 is a suitable scaffold for wound healing. Therefore, we suggest that 2-GHC-FD-8/F3 is a useful wound dressing for accelerating wound healing.

Macrophage reprogramming into a pro-healing phenotype by siRNA delivered with LBL assembled nanocomplexes for wound healing applications

Excessive inflammatory responses in wounds are characterized by the presence of high levels of pro-inflammatory M1 macrophages rather than pro-healing M2 macrophages, which leads to delayed wound healing. Macrophage reprogramming from the M1 to M2 phenotype through knockdown of interferon regulatory factor 5 (irf5) has emerged as a possible therapeutic strategy. While downregulation of irf5 could be achieved by siRNA, it very much depends on successful intracellular delivery by suitable siRNA carriers. Here, we report on highly stable selenium-based layer-by-layer (LBL) nanocomplexes (NCs) for siRNA delivery with polyethyleneimine (PEI-LBL-NCs) as the final polymer layer. PEI-LBL-NCs showed good protection of siRNA with only 40% siRNA release in a buffer of pH = 8.5 after 72 h or in simulated wound fluid after 4 h. PEI-LBL-NCs also proved to be able to transfect RAW 264.7 cells with irf5-siRNA, resulting in successful reprogramming to the M2 phenotype as evidenced by a 3.4 and 2.6 times decrease in NOS-2 and TNF-α mRNA expression levels, respectively. Moreover, irf5-siRNA transfected cells exhibited a 2.5 times increase of the healing mediator Arg-1 and a 64% increase in expression of the M2 cell surface marker CD206⁺. Incubation of fibroblast cells with conditioned medium isolated from irf5-siRNA transfected RAW 264.7 cells resulted in accelerated wound healing in an in vitro scratch assay. These results show that irf5-siRNA loaded PEI-LBL-NCs are a promising therapeutic approach to tune macrophage polarization for improved wound healing.

A freeze-thaw PVA hydrogel loaded with guava leaf extract: physical and antibacterial properties

A polyvinyl alcohol (PVA) hydrogel loaded with guava leaf extract (GLE) has potential applications as a wound dressing with good antibacterial activity. This study succeeded in fabricating a PVA hydrogel containing GLE using the freeze-thaw (FT) method. By varying the GLE concentration, we can adjust the physical properties of the hydrogel. The addition of GLE results in a decrease in cross-linking during gelation and an increase in the pore size of the hydrogels. The increase of the pore size made the swelling increase and the mechanical strength decrease. The weight loss of the hydrogel also increases because the phosphate buffer saline (PBS) dissolves the GLE. Increasing the GLE concentration caused the Fourier-transform infrared (FTIR) absorbance peaks to widen due to hydrogen bonds formed during the FT process. The crystalline phase was transformed into an amorphous phase in the PVA/GLE hydrogel based on the X-ray diffraction (XRD) spectra. The differential scanning calorimetry (DSC) characterization showed a significant decrease in the hydrogel weight over temperatures of 30-150 °C due to the evaporation of water from the hydrogel matrix. The zone of inhibition of the PVA/GLE hydrogel increased with antibacterial activity against Staphylococcus aureus of 17.93% per gram and 15.79% per gram against Pseudomonas aeruginosa.

Evaluation of pro-angiogenic properties of an inorganic silica gel fibre fleece

Hard-to-heal wounds represent an increasing health and economic burden on society. At present, therapy options for hard-to-heal wounds are often unsatisfactory, and the development of more effective wound treatments is urgently needed. We have shown that orthosilicic acid-releasing silica fibre fleece (SIFIB), via its pronounced anti-inflammatory properties, exhibited a significantly enhanced effect on wound closure kinetics in a porcine wound model in vivo. In this present study, we have examined in vitro the impact of the pro-angiogenic potential of SIFIB. Using an in vitro angiogenesis assay we describe for the first time how an inorganic biodegradable silica-based material significantly improved endothelial microvessel-like structure formation. We further demonstrate that the molecular mechanism of this pro-angiogenic activity of SIFIB is based on a significantly increased and tumour necrosis factor (TNF)α-dependent VEGF protein expression. In conclusion, due to its positive effects on angiogenesis, our results further indicate that decomposition products of silica-based biodegradable inorganic materials might represent very relevant therapeutic components of modern wound dressings for the treatment of hard-to-heal wounds.