Skin Wound Healing Process and New Emerging Technologies for Skin Wound Care and Regeneration

Application of chitosan nanoparticles in skin wound healing

The rising prevalence of impaired wound healing and the consequential healthcare burdens have gained increased attention over recent years. This has prompted research into the development of novel wound dressings with augmented wound healing functions. Nanoparticle (NP)-based delivery systems have become attractive candidates in constructing such wound dressings due to their various favourable attributes. The non-toxicity, biocompatibility and bioactivity of chitosan (CS)-based NPs make them ideal candidates for wound applications. This review focusses on the application of CS-based NP systems for use in wound treatment. An overview of the wound healing process was presented, followed by discussion on the properties and suitability of CS and its NPs in wound healing. The wound healing mechanisms exerted by CS-based NPs were then critically analysed and discussed in sections, namely haemostasis, infection prevention, inflammatory response, oxidative stress, angiogenesis, collagen deposition, and wound closure time. The results of the studies were thoroughly reviewed, and contradicting findings were identified and discussed. Based on the literature, the gap in research and future prospects in this research area were identified and highlighted. Current evidence shows that CS-based NPs possess superior wound healing effects either used on their own, or as drug delivery vehicles to encapsulate wound healing agents. It is concluded that great opportunities and potentials exist surrounding the use of CSNPs in wound healing.

Bee-Derived Products: Chemical Composition and Applications in Skin Tissue Engineering

Skin tissue regeneration is one of the population's most common problems, and the complications that may appear in the healing process can have detrimental consequences. An alternative to conventional treatments could be represented by sustainable materials based on natural products, such as honey and its derivates (propolis, royal jelly, bee pollen, beeswax, and bee venom). They exhibit significant inhibitory activities against bacteria and have great potential in dermal tissue regeneration. Research in the pharmaceutical field demonstrates that conventional medication combined with bee products can deliver better results. The advantages include minimizing side effects and maintaining the same effectiveness by using low concentrations of antibiotic, anti-inflammatory, or chemotherapy drugs. Several studies suggested that bee products can replace the antimicrobial activity and efficiency of antibiotics, but further investigation is needed to establish a topical mixture's potential, including honey, royal jelly, and propolis. Bee products seem to complete each other's deficiencies, and their mixture may have a better impact on the wound healing process. The topic addressed in this paper highlights the usefulness of honey, propolis, royal jelly, bee pollen, beeswax, and bee venom in the re-epithelization process and against most common bacterial infections.

In Vitro and In Vivo Wound Healing Activity of Astragalus floccosus Boiss. (Fabaceae)

Estrogens are a group of sex hormones which have receptors on the skin and lead to increased cells and wound healing. Normally isoflavonoids are present in Astragalus floccosus Boiss. (Leguminosae). Therefore, the present study was conducted to evaluate the presence of isoflavonoids in A. floccosus' rich fraction of flavonoid and evaluate its wound healing effect accordingly. Flavonoids were evaluated by LCMS. Scratch was conducted and the medium culture was treated with the Astragalus' rich fraction of flavonoid (RFF) and was compared with nontreated culture during 48 hours. In addition, in vivo full-thickness wound healing evaluation was performed on rats. The rats were put into four groups and treated on a daily basis for 21 days with a cream containing 1.5% of the RFF (group 1), silver sulfadiazine (group 2), and Vaseline (group 3) separately. The nontreated group (group 4) was created for a better comparison. During the examination, wound size was evaluated and histopathological examination was performed. Herbal analysis detected 11 flavonoids, including 2 isoflavonoids, Calycosin-7-O-beta-D-glucoside and Formononetin, in the RFF. In vitro scratch wound healing showed significant improvement with RFF treatment in comparison to nontreated medium. Furthermore, in vitro drug release of Astragalus ointment showed a stationary line during 24 h and 0.14 mg/ml of flavonoid penetrated the skin. In vivo wound size evaluation showed significant improvement in the group treated with the RFF in comparison to other groups. Histopathological results indicated that congestion, edema, inflammation, necrosis, and angiogenesis decreased during the examination and fibroblast proliferation fibrosis epithelization was increased especially in the RFF group in comparison to the silver sulfadiazine and free groups. In conclusion, A. floccosus showed that wound healing activity in both in vitro and in vivo analyses can be attributed to the presence of isoflavonoids with estrogen-like activity in this plant.

Nanomaterials-based drug delivery approaches for wound healing

Abstract:

Wound healing is a complex and dynamic process that requires intricate synchronization between multiple cell types within appropriate extracellular microenvironment. Wound healing process involves four overlapping phases in a precisely regulated manner, consisting of hemostasis, inflammation, proliferation, and maturation. For an effective wound healing all four phases must follow in a sequential pattern within a time frame. Several factors might interfere with one or more of these phases in healing process, thus causing improper or impaired wound healing resulting in non-healing chronic wounds. The complications associated with chronic non-healing wounds, along with the limitations of existing wound therapies, have led to the development and emergence of novel and innovative therapeutic interventions. Nanotechnology presents unique and alternative approaches to accelerate the healing of chronic wounds by the interaction of nanomaterials during different phases of wound healing. This review focuses on recent innovative nanotechnology-based strategies for wound healing and tissue regeneration based on nanomaterials, including nanoparticles, nanocomposites and scaffolds. The efficacy of the intrinsic therapeutic potential of nanomaterials (including silver, gold, zinc oxide, copper, cerium oxide, etc.) and the ability of nanomaterials as carriers (liposomes, hydrogels, polymeric nanomaterials, nanofibers) as therapeutic agents associated with wound-healing applications have also been addressed. The significance of these nanomaterial-based therapeutic interventions for wound healing needs to be highlighted to engage researchers and clinicians towards this new and exciting area of bio-nanoscience. We believe that these recent developments will offer researchers an updated source on the use of nanomaterials as an advanced approach to improve wound healing.

Emerging treatment strategies in wound care

Wound healing is a complex process in tissue regeneration through which the body responds to the dissipated cells as a result of any kind of severe injury. Diabetic and non-healing wounds are considered an unmet clinical need. Currently, different strategic approaches are widely used in the treatment of acute and chronic wounds which include, but are not limited to, tissue transplantation, cell therapy and wound dressings, and the use of an instrument. A large number of literatures have been published on this topic; however, the most effective clinical treatment remains a challenge. The wound dressing involves the use of a scaffold, usually using biomaterials for the delivery of medication, autologous stem cells, or growth factors from the blood. Antibacterial and anti-inflammatory drugs are also used to stop the infection as well as accelerate wound healing. With an increase in the ageing population leading to diabetes and associated cutaneous wounds, there is a great need to improve the current treatment strategies. This research critically reviews the current advancement in the therapeutic and clinical approaches for wound healing and tissue regeneration. The results of recent clinical trials suggest that the use of modern dressings and skin substitutes is the easiest, most accessible, and most cost-effective way to treat chronic wounds with advances in materials science such as graphene as 3D scaffold and biomolecules hold significant promise. The annual market value for successful wound treatment exceeds over $50 billion US dollars, and this will encourage industries as well as academics to investigate the application of emerging smart materials for modern dressings and skin substitutes for wound therapy.

Therapeutic potential of second degree's skin burns by topical dressing of Teucrium ramosissimum that promotes re-epithelialization

The aim of the report is to assess the protective effect of powder aerial part of T. ramosissimum (TS) on the in vivo wound-healing of second-degree burn injuries. Teucrium phytocompounds were characterized by FTIR, HPLC and GC/MS spectra. Burn wound models were employed to evaluate the in vivo wound-healing activity. Thirty six wistar rats with burn wounds were divided into six groups and treated daily with TS, the mixture of Teucrium and honey (TS-HY), thymol and Dermosalic® (0.05%) (DS) creams. Skin epithelialization was monitored on the 4th, 13th and 21st days. Proteins and the level of malondialdehyde (MDA) in the burned skin were assessed. Microscopic and macroscopic investigations of skin wound tissues showed significant wound closure rate via complete epidermal reepithelization and regeneration, higher protein content, collagen synthesis and deposition, hair follicles growth post wounding that were promoted in TS-, thymol-, TS-HY- and DS-treated wound tissues compared to the untreated burned wound tissues that was caracterised by the absence of the epithelialization, vascularization and the formation of the epidermis layer. Additionally, the skin healing potential of TS and TS-HY was validated by markedly decreased of lipid peroxidation. Overall, TS was found to possess complete wound closure and improves the healing process.

Bioactive peptides laden nano and micro-sized particles enriched ECM inspired dressing for skin regeneration in diabetic wounds

Hard to heal wounds such as diabetic wounds is one of the major problems in the healthcare sector. Delayed healing and shortfall of functional restoration at the wound site require upgraded wound management aids. In this study, we report that a nanofibrous mat enriched with bioactive peptides laden nano and microparticles achieve the requirements as an effective diabetic wound dressing. By means of electrospinning method, we fabricated Poly (lactic-co-glycolic acid)/Collagen nano-scale mat and surface functionalised with wound healing peptides, laden Chitosan nano and micro-sized particles, creating an Extracellular Matrix (ECM) -like structure with biomimetic features. The developed dressing displayed good cytocompatibility with Keratinocyte and fibroblast cells and enhanced their in-vitro cell proliferation and migration. Experiments in the streptozotocin-induced diabetic mice model showed that bioactive peptides released from Chitosan particles shorten the inflammatory stage and promote neovascularisation. The supporting nanoscale matrix promotes increased collagen deposition in the wound beds, thereby hastening the complete healing process by substantial tissue re-generation and functional restoration. The results evince that the nano/microparticles enriched nano-scale mat show potential as an effective wound repair dressing for diabetic wounds.

Preparation of silane-dispersed graphene crosslinked vinyl carboxymethyl chitosan temperature-responsive hydrogel with antibacterial properties

We synthesized a temperature-sensitive antibacterial hydrogel, defined as NIPAM-CG/GM hydrogel. First, vinyl carboxymethyl chitosan (CG) was synthesized as a crosslinking carrier and silane dispersed graphene (GM) was synthesized as a reinforcer. Then, the N-isopropylacrylamide (NIPAM) monomer was free-radical polymerized with the vinyl groups of CG and GM to form a NIPAM-CG/GM hydrogel without any crosslinking agent. The influences of different hydrogel compositions on the microstructure, compressive properties, swelling, drug loading, and drug release properties of the hydrogels were discussed, and its temperature sensitivity was also demonstrated. The results showed that the lower critical solution temperature (LCST) and mechanical properties of the hydrogel could be adjusted by controlling the amount of CG and GM. Next, its biocompatibility was characterized, and its antibacterial performance was tested against Escherichia coli and Staphylococcus aureus. The antibacterial mechanism was explained by measuring the difference in the ion concentration outside the membrane and changes in the morphology of live/dead bacteria. NIPAM-CG/GM had a high drug loading and nearly complete drug release at a physiological temperature of 37 °C. Its moderate mechanical properties, excellent biocompatibility, and antibacterial effects give NIPAM-CG/GM great potential applications as a wound dressing.

Characterization of Onchidiid Slug (Onchidium typhae) West Kalimantan Waters as Antibacterials and Antifungal

Onchidiid slug (Onchidium typhae) is a nudibranch that coastal communities in West Kalimantan have widely used as wounds. The study aims to characterize the West Kalimantan water O. typhae as antibacterial and antifungal. The study of O. typhae was carried out in several stages: preparation and optimization, extraction by Quinn method, characterization and identification of bioactive compounds, and antibacterial and antifungal assay using the microdilution method. The result of the proximate test showed that O. typhae powder contains high protein, namely 67.68%. Phytochemical screening results from methanol, ethyl acetate, and chloroform extracts contain alkaloids and amino acids. Methanol, chloroform, and ethyl acetate extract 1% of O. typhae showed inhibitory activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. The most significant inhibition value was indicated by chloroform extract 1%, where the inhibition value against S. aureus, E. coli, and C. albicans was 82±0.01%; 85.8±0.01%; 85±0.01%, respectively. From these results, O. typhae powder can be developed as a wound medicine through its antibacterial and antifungal activity.

Wound Dressing: From Nanomaterials to Diagnostic Dressings and Healing Evaluations

Wound dressings based on nanomaterials play a crucial role in wound treatment and are widely used in a whole range of medical settings, from minor to life-threatening tissue injuries. This article presents an educational review on the accumulating knowledge in this multidisciplinary area to lay out the challenges and opportunities that lie ahead and ignite the further and faster development of clinically valuable technologies. The review analyzes the functional advantages of nanomaterial-based gauzes and hydrogels as well as hybrid structures thereof. On this basis, the review presents state-of-the-art advances to transfer the (semi)blind approaches to the evaluation of a wound state to smart wound dressings that enable real-time monitoring and diagnostic functions that could help in wound evaluation during healing. This review explores the translation of nanomaterial-based wound dressings and related medical aspects into real-world use. The ongoing challenges and future opportunities associated with nanomaterial-based wound dressings and related clinical decisions are presented and reviewed.

The 3D Bioprinted Scaffolds for Wound Healing

Skin tissue engineering and regeneration aim at repairing defective skin injuries and progress in wound healing. Until now, even though several developments are made in this field, it is still challenging to face the complexity of the tissue with current methods of fabrication. In this review, short, state-of-the-art on developments made in skin tissue engineering using 3D bioprinting as a new tool are described. The current bioprinting methods and a summary of bioink formulations, parameters, and properties are discussed. Finally, a representative number of examples and advances made in the field together with limitations and future needs are provided.

[Effects of P311 on the angiogenesis ability of human microvascular endothelial cell 1 in vitro and its molecular mechanism]

Objective: To explore the effects of P311 on the angiogenesis ability of human microvascular endothelial cell 1 (HMEC-1) in vitro and the potential molecular mechanism. Methods: The experimental research method was used. HMEC-1 was collected and divided into P311 adenovirus group and empty adenovirus group according to the random number table (the same grouping method below), which were transfected correspondingly for 48 h. The cell proliferation activity was detected using the cell counting kit 8 on 1, 3, and 5 days of culture. The residual scratch area of cells at post scratch hour 6 and 11 was detected by scratch test, and the percentage of the residual scratch area was calculated. The blood vessel formation of cells at 8 h of culture was observed by angiogenesis experiment in vitro, and the number of nodes and total length of the tubular structure were measured. The protein expressions of vascular endothelial growth factor receptor 2 (VEGFR2), phosphorylated VEGFR2 (p-VEGFR2), extracellular signal-regulated kinase 1/2 (ERK1/2), and phosphorylated ERK1/2 (p-ERK1/2) in cells were detected by Western blotting. HMEC-1 was collected and divided into P311 adenovirus+small interfering RNA (siRNA) negative control group, empty adenovirus+siRNA negative control group, P311 adenovirus+siRNA-VEGFR2 group, and empty adenovirus+siRNA-VEGFG2 group, which were treated correspondingly. The protein expressions of VEGFR2, p-VEGFR2, ERK1/2, and p-ERK1/2 in cells were detected by Western blotting at 24 h of transfection. The blood vessel formation of cells at 24 h of transfection was observed by angiogenesis experiment in vitro, and the number of nodes and total length of the tubular structure were measured. HMEC-1 was collected and divided into P311 adenovirus+dimethylsulfoxide (DMSO) group, empty adenovirus+DMSO group, P311 adenovirus+ERK1/2 inhibitor group, and empty adenovirus+ERK1/2 inhibitor group, which were treated correspondingly. The protein expressions of ERK1/2 and p-ERK1/2 in cells were detected by Western blotting at 2 h of treatment. The blood vessel formation of cells at 2 h of treatment was observed by angiogenesis experiment in vitro, and the number of nodes and total length of the tubular structure were measured. The sample number at each time point in each group was 6. Data were statistically analyzed with independent sample t test, analysis of variance for repeated measurement, one-way analysis of variance, and least significant difference test. Results: Compared with that of empty adenovirus group, the proliferation activity of cells in P311 adenovirus group did not show significant difference on 1, 3, and 5 days of culture (with t values of -0.23, -1.30, and -1.52, respectively, P>0.05). The residual scratch area percentages of cells in P311 adenovirus group were significantly reduced at post scratch hour 6 and 11 compared with those of empty adenovirus group (with t values of -2.47 and -2.62, respectively, P<0.05). At 8 h of culture, compared with those of empty adenovirus group, the number of nodes and total length of the tubular structure of cells in P311 adenovirus group were significantly increased (with t values of 4.49 and 4.78, respectively, P<0.01). At 48 h of transfection, compared with those of empty adenovirus group, the protein expressions of VEGFR2 and ERK1/2 of cells in P311 adenovirus group showed no obvious changes (P>0.05), and the protein expressions of p-VEGFR2 and p-ERK1/2 of cells in P311 adenovirus group were significantly increased (with t values of 17.27 and 16.08, P<0.01). At 24 h of transfection, the protein expressions of p-VEGFR2 and p-ERK1/2 of cells in P311 adenovirus+siRNA negative control group were significantly higher than those in empty adenovirus+siRNA negative control group (P<0.01). The protein expressions of VEGFR2, p-VEGFR2, and p-ERK1/2 of cells in P311 adenovirus+siRNA negative control group were significantly higher than those in P311 adenovirus+siRNA-VEGFR2 group (P<0.01). The protein expressions of VEGFR2 and p-ERK1/2 of cells in empty adenovirus+siRNA negative control group were significantly higher than those in empty adenovirus+siRNA-VEGFR2 group (P<0.05 or P<0.01). At 24 h of transfection, the number of nodes of the tubular structure in cells of P311 adenovirus+siRNA negative control group was 720±62, which was significantly more than 428±38 in empty adenovirus+siRNA negative control group and 364±57 in P311 adenovirus+siRNA-VEGFR2 group (with P values both <0.01). The total length of the tubular structure of cells in P311 adenovirus+siRNA negative control group was (21 241±1 139) μm, which was significantly longer than (17 005±1 156) μm in empty adenovirus+siRNA negative control group and (13 494±2 465) μm in P311 adenovirus+siRNA-VEGFR2 group (with P values both <0.01). The number of nodes of the tubular structure in cells of empty adenovirus+siRNA negative control group was significantly more than 310±75 in empty adenovirus+siRNA-VEGFR2 group (P<0.01), and the total length of the tubular structure of cells in empty adenovirus+siRNA negative control group was significantly longer than (11 600±2 776) μm in empty adenovirus+siRNA-VEGFR2 group (P<0.01). At 2 h of treatment, the protein expression of p-ERK1/2 of cells in P311 adenovirus+DMSO group was significantly higher than that in empty adenovirus+DMSO group and P311 adenovirus+ERK1/2 inhibitor group (with P values both <0.01), and the protein expression of p-ERK1/2 of cells in empty adenovirus+DMSO group was significantly higher than that in empty adenovirus+ERK1/2 inhibitor group (P<0.05). At 2 h of treatment, the number of nodes of the tubular structure in cells of P311 adenovirus+DMSO group was 726±72, which was significantly more than 421±39 in empty adenovirus+DMSO group and 365±41 in P311 adenovirus+ERK1/2 inhibitor group (with P values both <0.01). The total length of the tubular structure of cells in P311 adenovirus+DMSO group was (20 318±1 433) μm, which was significantly longer than (16 846±1 464) μm in empty adenovirus+DMSO group and (15 114±1 950) μm in P311 adenovirus+ERK1/2 inhibitor group (with P values both <0.01). The number of nodes of the tubular structure in cells of empty adenovirus+DMSO group was significantly more than 317±67 in empty adenovirus+ERK1/2 inhibitor group (P<0.01), and the total length of the tubular structure of cells in empty adenovirus+DMSO group was significantly longer than (13 188±2 306) μm in empty adenovirus+ERK1/2 inhibitor group (P<0.01). Conclusions: P311 can enhance the angiogenesis ability of HMEC-1 by activating the VEGFR2/ERK1/2 signaling pathway.

Adipose Stem Cell-Based Treatments for Wound Healing

Wound healing is one of the most complex physiological regulation mechanisms of the human body. Stem cell technology has had a significant impact on regenerative medicine. Adipose stem cells (ASCs) have many advantages, including their ease of harvesting and high yield, rich content of cell components and cytokines, and strong practicability. They have rapidly become a favored tool in regenerative medicine. Here, we summarize the mechanism and clinical therapeutic potential of ASCs in wound repair.

Phytochemical Profile, Antioxidant and Wound Healing Potential of Three Artemisia Species: In Vitro and In Ovo Evaluation

Skin injuries, and especially wounds of chronic nature, can cause a major negative impact on the quality of life. New efficient alternatives are needed for wound healing therapy and herbal products are being investigated due to a high content of natural compounds with promising healing activity. For this purpose, we investigated three Artemisia species, Artemisia absinthium L. (AAb), Artemisia dracunculus L. (ADr) and Artemisia annua L. (AAn). Ethanolic extracts, containing different polyphenolic compounds, elicited strong antioxidant activities in the DPPH assay, comparable to ascorbic acid. Human ketratinocyte proliferation was stimulated and wound closure was enhanced by all three extracts at concentrations of 100 µg/mL. The Artemisia extracts modulated angiogenesis by increasing vessel formation, especially following treatment with A. annua and A. dracunculus, extracts with a significantly higher content of chlorogenic acid. Good tolerability and anti-irritative effects were also registered in ovo, on the chorioallantoic membrane (CAM). The three Artemisia species represent promising low-cost, polyphenol-rich, antioxidant, safe alternatives for wound care treatment.

Combination Therapy of Stem Cell-derived Exosomes and Biomaterials in the Wound Healing

Wound healing is a serious obstacle due to the complexity of evaluation and management. While novel approaches to promoting chronic wound healing are of critical interest at the moment, several studies have demonstrated that combination therapy is critical for the treatment of a variety of diseases, particularly chronic wounds. Among the various approaches that have been proposed for wound care, regenerative medicine-based methods have garnered the most attention. As is well known, regenerative medicine's three primary tools are gene/cell therapy, biomaterials, and tissue engineering. Multifunctional biomaterials composed of synthetic and natural components are highly advantageous for exosome carriers, which utilizing them is an exciting wound healing method. Recently, stem cell-secreted exosomes and certain biomaterials have been identified as critical components of the wound healing process, and their combination therapy appears to produce significant results. This paper presents a review of literature and perspectives on the use of stem cell-derived exosomes and biomaterials in wound healing, particularly chronic wounds, and discusses the possibility of future clinical applications.

The application of mesenchymal stromal cells (MSCs) and their derivative exosome in skin wound healing: a comprehensive review

Recently, mesenchymal stromal cells (MSCs) and also their exosome has become a game-changing tool in the context of tissue engineering and regenerative medicine. MSCs due to their competencies to establish skin cells, such as fibroblast and keratinocyte, and also their unique attribute to suppress inflammation in wound site has attracted increasing attention among scholars. In addition, MSC's other capabilities to induce angiogenesis as a result of secretion of pro-angiogenic factors accompanied with marked anti-fibrotic activities, which mainly mediated by the releases matrix metalloproteinase (MMPs), make them a rational and effective strategy to accelerate wound healing with a small scar. Since the chief healing properties of the MSCs depend on their paracrine effects, it appears that MSCs-derived exosomes also can be an alternative option to support wound healing and skin regeneration as an innovative cell-free approach. Such exosomes convey functional cargos (e.g., growth factor, cytokine, miRNA, etc.) from MSCs to target cells, thereby affecting the recipient skin cells' biological events, such as migration, proliferation, and also secretion of ECM components (e.g., collagen). The main superiorities of exosome therapy over parental MSCs are the diminished risk of tumor formation and also lower immunogenicity. Herein, we deliver an overview of recent in vivo reports rendering the therapeutic benefits of the MSCs-based therapies to ease skin wound healing, and so improving quality of life among patients suffering from such conditions.

A soft intelligent dressing with pH and temperature sensors for early detection of wound infection

Wound infection is a common clinical problem. Traditional detection methods can not provide infection early warning information in time. With the development of flexible electronics, flexible wearable devices have been widely used in the field of intelligent monitoring. Here, we describe the development of a soft wound infection monitoring system with pH sensors and temperature sensors. The measurement range of pH was 4-10, the fitting accuracy was 99.8%, and the response time was less than 6 s. The temperature sensor array showed good accuracy and short response times in the range of 30 °C to 40 °C. A series of in vitro tests and the use of a rat model of Staphylococcus aureus infection confirmed that this flexible detection system can monitor the pH and temperature changes occurring in the early stage of infection, which provides an effective reference for clinical application.

Shape-Memory Polymers Hallmarks and Their Biomedical Applications in the Form of Nanofibers

Shape-Memory Polymers (SMPs) are considered a kind of smart material able to modify size, shape, stiffness and strain in response to different external (heat, electric and magnetic field, water or light) stimuli including the physiologic ones such as pH, body temperature and ions concentration. The ability of SMPs is to memorize their original shape before triggered exposure and after deformation, in the absence of the stimulus, and to recover their original shape without any help. SMPs nanofibers (SMPNs) have been increasingly investigated for biomedical applications due to nanofiber's favorable properties such as high surface area per volume unit, high porosity, small diameter, low density, desirable fiber orientation and nanoarchitecture mimicking native Extra Cellular Matrix (ECM). This review focuses on the main properties of SMPs, their classification and shape-memory effects. Moreover, advantages in the use of SMPNs and different biomedical application fields are reported and discussed.

An Up-to-Date Review of Biomaterials Application in Wound Management

Whether they are caused by trauma, illness, or surgery, wounds may occur throughout anyone's life. Some injuries' complexity and healing difficulty pose important challenges in the medical field, demanding novel approaches in wound management. A highly researched possibility is applying biomaterials in various forms, ranging from thin protective films, foams, and hydrogels to scaffolds and textiles enriched with drugs and nanoparticles. The synergy of biocompatibility and cell proliferative effects of these materials is reflected in a more rapid wound healing rate and improved structural and functional properties of the newly grown tissue. This paper aims to present the biomaterial dressings and scaffolds suitable for wound management application, reviewing the most recent studies in the field.

Topically administered purified clinoptilolite-tuff for the treatment of cutaneous wounds: a prospective, randomized phase I clinical trial

In an ageing society, chronic ulcers pose an increasingly relevant healthcare issue associated with significant morbidity and an increasing financial burden. Hence, there is an unmet medical need for novel, cost‐effective therapies that improve healing of chronic cutaneous wounds. This prospective, randomised, open‐label, phase I trial investigated the safety and tolerability of topically administered purified clinoptilolite‐tuff (PCT), mainly consisting of the naturally occurring zeolite‐mineral clinoptilolite, in artificial wounds in healthy male volunteers compared to the standard of care (SoC). We found that topically administered PCT was safe for therapeutic application in acute wounds in healthy male volunteers. No significant differences in wound healing or wound conditions were observed compared to SoC‐treated wounds. However, we found a significantly higher proportion of CD68‐positive cells and a significantly lower proportion of α‐smooth muscle actin‐positive cells in PCT‐treated wounds. Scanning electron microscopy revealed PCT particles in the restored dermis in some cases. However, these did not impede wound healing or clinical symptoms. Hence, purified PCT could represent an attractive, cost‐effective wound treatment promoting the process of healing.

Antimicrobial and Wound-Healing Activities of Graphene-Reinforced Electrospun Chitosan/Gelatin Nanofibrous Nanocomposite Scaffolds

This study aims at preparing electrospun chitosan/gelatin nanofiber scaffolds reinforced with different amounts of graphene nanosheets to be used as antibacterial and wound-healing scaffolds. Full characterization was carried out for the different fabricated scaffolds before being assessed for their antimicrobial activity against Escherichia coli and Staphylococcus aureus, cytotoxicity, and cell migration capacity. Raman and transmission electron microscopies confirmed the successful reinforcement of nanofibers with graphene nanosheets. Scanning electron microscopy and porosity revealed that nanofibers reinforced with 0.15% graphene nanosheets produced the least diameter (106 ± 30 nm) and the highest porosity (90%), in addition to their good biodegradability and swellability. However, the excessive increase in graphene nanosheet amount produced beaded nanofibers with decreased porosity, swellability, and biodegradability. Interestingly, nanofibers reinforced with 0.15% graphene nanosheets showed E. coli and S. aureus growth inhibition percents of 50 and 80%, respectively. The cell viability assay showed no cytotoxicity on human fibroblasts when cultured with either unreinforced or reinforced nanofibers. The cell migration was higher in the case of reinforced nanofibers when compared to the unreinforced nanofibers after 24 and 48 h, which is substantially associated with the great effect of the graphene nanosheets on the cell migration capability. Unreinforced and reinforced nanofibers showed cell migration results up to 93.69 and 97%, respectively, after 48 h.

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.

Highly Adhesive Antibacterial Bioactive Composite Hydrogels With Controllable Flexibility and Swelling as Wound Dressing for Full-Thickness Skin Healing

Polyzwitterionic hydrogels as skin wound dressings have been extensively studied owing to their superior antibacterial properties and skin adhesiveness, but their practical applications still suffer from a low adhesion strength and a high swelling ratio, which hinder the application of hydrogel for cutaneous healing. Here, we developed a novel biocompatible poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (PolySBMA) composite hydrogel with high stretchability, low swelling, strong skin adhesiveness, and antibacterial effect for enhancing wound healing. Naturally rigid polymers including quaternized chitosan methacrylate (QCSMA) and gelatin methacrylate (GelMA) are used as bioactive cross-linkers to endow PolySBMA/QCSMA/GelMA (SQG) hydrogel with a low swelling ratio and high bioactivity. The optimized hydrogel has excellent mechanical flexibility, with the ultimate tensile strength, tensile strain, modulus, and toughness of up to 344.5 kPa, 364%, 14.7 kPa, and 33.4 kJ m⁻³, respectively. The adhesiveness of the hydrogel to the skin tissue is as high as 38.2 kPa, which is critical for stopping the bleeding from the wound. The synergistic contributions from the PolySBMA and QCSMA endow hydrogel with good antibacterial properties against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Moreover, the natural polymer cross-linked polyzwitterionic hydrogel shows good cell activity, hemocompatibility, and histocompatibility. The in vivo full-thickness skin defect model demonstrates that the SQG hydrogel efficiently improves the granulation tissue formation and collagen deposition. In summary, such superiorly skin-adhesive antibacterial biocompatible hydrogel with controllable flexibility and swelling holds great promise as wound dressings for acute wounds.

Macrophage polarisation in caesarean scar diverticulum

AIMS

To determine immunohistochemical features and correlations between M1/M2 polarisation status with disease severity of post-caesarean scar diverticulum (CSD).

METHODS

Histological and immunohistological stainings were performed and inflammatory (CD16, CD163 and tumour necrosis factor-α (TNF-α)), fibrosis (α-smooth muscle actin (α-SMA)) and angiogenic (CD31) markers were examined in uterine tissues collected from patients with uterine scar diverticula (CSD) (n=37) and caesarean section (CS) (n=3).

RESULTS

CSD tissues have higher expression of α-SMA, TNF-α, CD16 and CD31 and lower expression of CD163 than CS tissue (p<0.05). Compared with adjacent tissues, thick-walled blood vessels, glands and fibrotic sites have higher expression of α-SMA, TNF-α and CD16. Statistical correlation was observed between the expression of CD16 and TNF-α (R=0.693, p<0.001), α-SMA (R=0.404, p<0.05) and CD31 (R=0.253, p<0.05) in CSD tissues, especially with the ratio of CD16/CD163 (R=0.590, p<0.01). A more significant difference was observed between the expression of CD16/CD163 and α-SMA (R=0.556, p<0.001), TNF-α (R=0.633, p<0.0001) and CD31 (R=0.336, p<0.05).

CONCLUSIONS

In this study, TNF-α, α-SMA, CD16 and CD31 proteins were overexpressed in all CSD cases, and CD16/CD163 was positively correlated with tissue inflammation, fibrosis and neovascularisation. Abnormal mononuclear macrophage infiltration may be involved in the origin and progression of CSD.

Closure of defects in a geometric figure pattern associated with tumescent anesthesia with lidocaine in rabbits (Oryctolagus cuniculus)

Abstract The use of tumescent anesthesia with lidocaine can provide better intra- and postoperative analgesia that would benefit extensive reconstructive surgery. However, lidocaine can interfere with the healing process. Therefore, this study aimed to assess the local interference of the healing of induced and closed skin defects in a geometric pattern associated with the use of tumescent anesthesia with lidocaine in rabbits. Furthermore, we assessed its influence on cardiorespiratory parameters and postoperative analgesia. This study included 27 rabbits divided into three groups: GC (without the use of tumescence), GS (use of tumescence with 0.9% NaCl solution), and GL (use of tumescent anesthesia with lidocaine). There was no statistically significant intergroup difference in any stage of the wound healing process on macroscopic evaluations, in the angiogenesis process, or in the process of collagenization and fibroblast deposition. There were significant differences in heart rate (lower in GL), respiratory rate (higher in GC), mean arterial pressure (higher in GL), and expired concentration of isoflurane (lower in GL). There was no significant intergroup difference in the von Frey filament test or the visual analog scale score used to evaluate postoperative analgesia. We concluded that tumescent anesthesia with lidocaine does not impair postoperative tissue repair. Its use features benefits such as reducing the volume of inhaled anesthetic, maintaining the anesthesia plan, stable heart and respiratory rates, and lower hypotension during the surgical procedure.

Cellular Interaction of Human Skin Cells towards Natural Bioink via 3D-Bioprinting Technologies for Chronic Wound: A Comprehensive Review

Skin substitutes can provide a temporary or permanent treatment option for chronic wounds. The selection of skin substitutes depends on several factors, including the type of wound and its severity. Full-thickness skin grafts (SGs) require a well-vascularised bed and sometimes will lead to contraction and scarring formation. Besides, donor sites for full-thickness skin grafts are very limited if the wound area is big, and it has been proven to have the lowest survival rate compared to thick- and thin-split thickness. Tissue engineering technology has introduced new advanced strategies since the last decades to fabricate the composite scaffold via the 3D-bioprinting approach as a tissue replacement strategy. Considering the current global donor shortage for autologous split-thickness skin graft (ASSG), skin 3D-bioprinting has emerged as a potential alternative to replace the ASSG treatment. The three-dimensional (3D)-bioprinting technique yields scaffold fabrication with the combination of biomaterials and cells to form bioinks. Thus, the essential key factor for success in 3D-bioprinting is selecting and developing suitable bioinks to maintain the mechanisms of cellular activity. This crucial stage is vital to mimic the native extracellular matrix (ECM) for the sustainability of cell viability before tissue regeneration. This comprehensive review outlined the application of the 3D-bioprinting technique to develop skin tissue regeneration. The cell viability of human skin cells, dermal fibroblasts (DFs), and keratinocytes (KCs) during in vitro testing has been further discussed prior to in vivo application. It is essential to ensure the printed tissue/organ constantly allows cellular activities, including cell proliferation rate and migration capacity. Therefore, 3D-bioprinting plays a vital role in developing a complex skin tissue structure for tissue replacement approach in future precision medicine.

Rational selection of bioactive principles for wound healing applications: Growth factors and antioxidants

Wound healing is a complex process of communication between growth factors, reactive species of oxygen, cells, signalling pathways, and cytokines in the extracellular matrix, in which growth factors are the key regulators. In humans, the main regulators of the cellular responses in wound healing are five growth factors, namely EGF, bFGF, VEGF, and TGF-β1. On the other hand, antioxidants such as astaxanthin, beta-carotene, epigallocatechin gallate, delphinidin, and curcumin have been demonstrated to stimulate cell proliferation, migration and angiogenesis, and control inflammation, to suggest a practical approach to design new strategies to treat non-healing cutaneous conditions. Based on the individual effects of growth factors and antioxidants, it may be envisioned that the use of both types of bioactives in wound healing formulations may have an additive or synergistic effect on the healing potential. This review addresses the effect of growth factors and antioxidants on wound healing-related processes. Furthermore, a prospective on their potential additive or synergistic effect on wound healing formulations, based on their individual effects, is presented. This may serve as a guide for the development of a new generation of wound healing formulations.

RJX Improves Wound Healing in Diabetic Rats

BACKGROUND

We recently reported the clinical safety profile of RJX, a well-defined intravenous GMP-grade pharmaceutical formulation of anti-oxidant and anti-inflammatory vitamins as active ingredients, in a Phase 1 study in healthy volunteers (ClinicalTrials.gov Identifier: NCT03680105) (Uckun et al., Front. Pharmacol. 11, 594321. 10.3389/fphar.2020.594321). The primary objective of the present study was to examine the effects of GMP-grade RJX on wound and burn injury healing in diabetic rats.

METHODS

In the present study, a rat model of T2DM was used that employs HFD in combination with a single injection of STZ intraperitoneally (i.p) at a moderate dose level (45 mg/kg). Anesthetized diabetic rats underwent full-thickness skin excision on the back or were subjected to burn injury via a heated brass probe and then started on treatments with normal saline (NS = vehicle) or RJX administered via intraperitoneal injections for three weeks.

FINDINGS

Notably, diabetic rats treated with the 1.25 mL/kg or 2.5 mL/kg RJX (DM+RJX groups) rapidly healed their wounds as fast as non-diabetic control rats. Inflammatory cell infiltration in the dermis along with fibrin and cell debris on the epithelial layer persisted for up to 14 days in the DM+NS group but not in RJX-treated groups. The histopathological score of wound healing on days 7 and 14 was better in diabetic rats treated with RJX than diabetic rats treated with NS and comparable to the scores for non-diabetic healthy rats consistent with an accelerated healing process. The residual wound area of RJX-treated rats was significantly smaller than that of NS-treated diabetic rats at each evaluation time point (P<0.001). The accelerating effect of RJX on diabetic wound healing was dose-dependent. We obtained similar results in the burn injury model. Our results demonstrate that RJX - at a dose level >10-fold lower than its clinical maximum tolerated dose (MTD) - accelerates the healing of excision wounds as well burn injury in diabetic rats.

Prevention of Postsurgical Abdominal Adhesion Using Electrospun TPU Nanofibers in Rat Model

Intra-abdominal adhesions following surgery are a challenging problem in surgical practice. This study fabricated different thermoplastic polyurethane (TPU) nanofibers with different average diameters using the electrospinning method. The conditions were evaluated by scanning electron microscopy (SEM), atomic force microscope (AFM), and Fourier transform infrared spectrometer (FTIR) analysis. A static tensile test was applied using a strength testing device to assess the mechanical properties of the electrospun scaffolds. By changing the effective electrospinning parameters, the best quality of nanofibers could be achieved with the lowest bead numbers. The electrospun nanofibers were evaluated in vivo using a rat cecal abrasion model. The macroscopic evaluation and the microscopic study, including the degree of adhesion and inflammation, were investigated after three and five weeks. The resultant electrospun TPU nanofibers had diameters ranging from about 200 to 1000 nm. The diameters and morphology of the nanofibers were significantly affected by the concentration of polymer. Uniform TPU nanofibers without beads could be prepared by electrospinning through reasonable control of the process concentration. These nanofibers' biodegradability and antibacterial properties were investigated by weight loss measurement and microdilution methods, respectively. The purpose of this study was to provide electrospun nanofibers having biodegradability and antibacterial properties that prevent any adhesions or inflammation after pelvic and abdominal surgeries. The in vivo experiments revealed that electrospun TPU nanofibers reduced the degree of abdominal adhesions. The histopathological study confirmed only a small extent of inflammatory cell infiltration in the 8% and 10% TPU. Conclusively, nanofibers containing 8% TPU significantly decreased the incidence and severity of postsurgical adhesions, and it is expected to be used in clinical applications in the future.

Development of a stem cell spheroid‐laden patch with high retention at skin wound site

Mesenchymal stem cells such as human adipose tissue‐derived stem cells (hADSCs) have been used as a representative therapeutic agent for tissue regeneration because of their high proliferation and paracrine factor‐secreting abilities. However, certain points regarding conventional ADSC delivery systems, such as low cell density, secreted cytokine levels, and cell viability, still need to be addressed for treating severe wounds. In this study, we developed a three‐dimensional (3D) cavity‐structured stem cell‐laden system for overdense delivery of cells into severe wound sites. Our system includes a hydrophobic surface and cavities that can enhance the efficiency of cell delivery to the wound site. In particular, the cavities in the system facilitate hADSC spheroid formation, increasing therapeutic growth factor expression compared with 2D cultured cells. Our hADSC spheroid‐loaded patch exhibited remarkably improved cell localization at the wound site and dramatic therapeutic efficacy compared to the conventional cell injection method. Taken together, the hADSC spheroid delivery system focused on cell delivery, and stem cell homing effect at the wound site showed a significantly enhanced wound healing effect. By overcoming the limitations of conventional cell delivery methods, our overdense cell delivery system can contribute to biomedical and clinical applications.

Design of Asymmetric Nanofibers-Membranes Based on Polyvinyl Alcohol and Wool-Keratin for Wound Healing Applications

The development of asymmetric membranes—i.e., matching two fibrous layers with selected composition and morphological properties to mimic both the epidermis and dermis—currently represents one of the most promising strategies to support skin regeneration during the wound healing process. Herein, a new asymmetric platform fabricated by a sequential electrospinning process was investigated. The top layer comprises cross-linked polyvinylalcohol (PVA) nanofibers (NFs)—from water solution—to replicate the epidermis’s chemical stability and wettability features. Otherwise, the bottom layer is fabricated by integrating PVA with wool-keratin extracted via sulfitolysis. This protein is a biocompatibility polymer with excellent properties for dermis-like structures. Morphological characterization via SEM supported by image analysis showed that the asymmetric membrane exhibited average fiber size—max frequency diameter 450 nm, range 1.40 μm—and porosity suitable for the healing process. FTIR-spectrums confirmed the presence of keratin in the bottom layer and variations of keratin-secondary structures. Compared with pure PVA-NFs, keratin/PVA-NFs showed a significant improvement in cell adhesion in in vitro tests. In perspective, these asymmetric membranes could be promisingly used to confine active species (i.e., antioxidants, antimicrobials) to the bottom layer to support specific cell activities (i.e., proliferation, differentiation) in wound healing applications.

The Role of Extracellular Matrix in Skin Wound Healing

Impaired wound healing is one of the unsolved problems of modern medicine, affecting patients’ quality of life and causing serious economic losses. Impaired wound healing can manifest itself in the form of chronic skin wounds or hypertrophic scars. Research on the biology and physiology of skin wound healing disorders is actively continuing, but, unfortunately, a single understanding has not been developed. The attention of clinicians to the biological and physiological aspects of wound healing in the skin is necessary for the search for new and effective methods of prevention and treatment of its consequences. In addition, it is important to update knowledge about genetic and non-genetic factors predisposing to impaired wound healing in order to identify risk levels and develop personalized strategies for managing such patients. Wound healing is a very complex process involving several overlapping stages and involving many factors. This thematic review focuses on the extracellular matrix of the skin, in particular its role in wound healing. The authors analyzed the results of fundamental research in recent years, finding promising potential for their transition into real clinical practice.

Growth factors, as biological macromolecules in bioactivity enhancing of electrospun wound dressings for diabetic wound healing: A review

Impaired wound healing is of the most conspicuous characteristics of diabetic mellitus. Reduced blood flow, chronic inflammatory reactions, infection, endothelial dysfunction, elevated levels of reactive oxygen species, and metabolic disorders cause wounds to heal more slowly in these patients. Previous studies have reported useful impacts of growth factors in management of such wounds. However, due to their short half-life and low stability, a suitable delivery platform with sustained release profile may boost their healing potential. Controlled and localized delivery of growth factors via electrospun fibers have been extensively explored in previous studies. The electrospinning method; although not new, has turned out to be extremely effective for the preparation of delivery carriers for growth factors. Due to their structural resemblance to native tissues' extracellular matrix, high encapsulation efficacy, tunability, and high surface to volume ratio, electrospun scaffolds have gained significant attention in drug delivery and tissue engineering. In the current review, careful integration of current research regarding the applications of growth factors' delivery through electrospun fibers in diabetic wounds healing has been done. This review will not only give an insight into the current updates, but will also highlights the future perspectives and challenges.

Collagen-Based Nanofibers for Skin Regeneration and Wound Dressing Applications

Skin regeneration after an injury is very vital, but this process can be impeded by several factors. Regenerative medicine is a developing biomedical field with the potential to decrease the need for an organ transplant. Wound management is challenging, particularly for chronic injuries, despite the availability of various types of wound dressing scaffolds in the market. Some of the wound dressings that are in clinical practice have various drawbacks such as poor antibacterial and antioxidant efficacy, poor mechanical properties, inability to absorb excess wound exudates, require frequent change of dressing and fails to offer a suitable moist environment to accelerate the wound healing process. Collagen is a biopolymer and a major constituent of the extracellular matrix (ECM), making it an interesting polymer for the development of wound dressings. Collagen-based nanofibers have demonstrated interesting properties that are advantageous both in the arena of skin regeneration and wound dressings, such as low antigenicity, good biocompatibility, hemostatic properties, capability to promote cellular proliferation and adhesion, and non-toxicity. Hence, this review will discuss the outcomes of collagen-based nanofibers reported from the series of preclinical trials of skin regeneration and wound healing.

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

Chitosan is one of the most studied natural origin polymers for biomedical applications. This review focuses on the potential of chitosan in localized antimicrobial therapy to address the challenges of current rising antimicrobial resistance. Due to its mucoadhesiveness, chitosan offers the opportunity to prolong the formulation residence time at mucosal sites; its wound healing properties open possibilities to utilize chitosan as wound dressings with multitargeted activities and more. We provide an unbiased overview of the state-of-the-art chitosan-based delivery systems categorized by the administration site, addressing the site-related challenges and evaluating the representative formulations. Specifically, we offer an in-depth analysis of the current challenges of the chitosan-based novel delivery systems for skin and vaginal infections, including its formulations optimizations and limitations. A brief overview of chitosan's potential in treating ocular, buccal and dental, and nasal infections is included. We close the review with remarks on toxicity issues and remaining challenges and perspectives.

3D in vitro M2 macrophage model to mimic modulation of tissue repair

Distinct anti-inflammatory macrophage (M2) subtypes, namely M2a and M2c, are reported to modulate the tissue repair process tightly and chronologically by modulating fibroblast differentiation state and functions. To establish a well-defined three-dimensional (3D) cell culture model to mimic the tissue repair process, we utilized THP-1 human monocytic cells and a 3D collagen matrix as a biomimetic tissue model. THP-1 cells were differentiated into macrophages, and activated using IL-4/IL-13 (M_IL-4/IL-13) and IL-10 (M_IL-10). Both activated macrophages were characterized by both their cell surface marker expression and cytokine secretion profile. Our cell characterization suggested that M_IL-4/IL-13 and M_IL-10 demonstrate M2a- and M2c-like subtypes, respectively. To mimic the initial and resolution phases during the tissue repair, both activated macrophages were co-cultured with fibroblasts and myofibroblasts. We showed that M_IL-4/IL-13 were able to promote matrix synthesis and remodeling by induction of myofibroblast differentiation via transforming growth factor beta-1 (TGF-β1). On the contrary, M_IL-10 demonstrated the ability to resolve the tissue repair process by dedifferentiation of myofibroblast via IL-10 secretion. Overall, our study demonstrated the importance and the exact roles of M2a and M2c-like macrophage subtypes in coordinating tissue repair in a biomimetic model. The established model can be applied for high-throughput platforms for improving tissue healing and anti-fibrotic drugs testing, as well as other biomedical studies.

Assessment of Anti-Inflammatory and Antimicrobial Potential of Ethanolic Extract of Woodfordia fruticosa Flowers: GC-MS Analysis

Currently, the potential utilization of natural plant-derived extracts for medicinal and therapeutic purposes has increased remarkably. The current study, therefore, aimed to assess the antimicrobial and anti-inflammatory activity of modified solvent evaporation-assisted ethanolic extract of Woodfordia fruticosa flowers. For viable use of the extract, qualitative analysis of phytochemicals and their identification was carried out by gas chromatography-mass spectroscopy. Analysis revealed that phenolic (65.62 ± 0.05 mg/g), flavonoid (62.82 ± 0.07 mg/g), and ascorbic acid (52.46 ± 0.1 mg/g) components were present in high amounts, while β-carotene (62.92 ± 0.02 µg/mg) and lycopene (60.42 ± 0.8 µg/mg) were present in lower amounts. The antimicrobial proficiency of modified solvent-assisted extract was evaluated against four pathogenic bacterial and one fungal strain, namely Staphylococcusaureus (MTCC 3160), Klebsiellapneumoniae (MTCC 3384), Pseudomonasaeruginosa (MTCC 2295), and Salmonellatyphimurium (MTCC 1254), and Candidaalbicans (MTCC 183), respectively. The zone of inhibition was comparable to antibiotics streptomycin and amphotericin were used as a positive control for pathogenic bacterial and fungal strains. The extract showed significantly higher (p < 0.05) anti-inflammatory activity during the albumin denaturation assay (43.56-86.59%) and HRBC membrane stabilization assay (43.62-87.69%). The extract showed significantly (p < 0.05) higher DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging assay and the obtained results are comparable with BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene) with percentage inhibitions of 82.46%, 83.34%, and 84.23%, respectively. Therefore, the obtained results concluded that ethanolic extract of Woodfordia fruticosa flowers could be utilized as a magnificent source of phenols used for the manufacturing of value-added food products.

A synergy between dopamine and electrostatically bound bactericide in a poly (vinyl alcohol) hybrid hydrogel for treating infected wounds

Antibacterial hydrogels have emerged as viable options for battling infections associated with impaired wound healing. It is challenging in developing antibacterial hydrogels that have sustained and stable bactericidal activity while avoiding the use of any agents that may adversely affect safety. In view of this concern, a multi-functional polyvinyl alcohol (PVA)/sodium alginate-dopamine (SA-DA) hydrogel matrix-based wound dressing embedding with bis-quaternary triphenyl-phosphonium salt (BTPP+), that would present long-term intrinsic antimicrobial properties was developed using freeze-thawing (F-T) method herein. DA endows the hydrogel with efficient bacteria capture ability and subsequently the captured bacterial pathogens were in situ killed by electrostatically bound BTPP+, and hence significantly augmented the antibacterial efficacy. Furthermore, DA, co-operating with BTPP+ could promote erythrocyte and platelet aggregation on hydrogels, which ensures hydrogels with improved hemostasis capacity. Thus, this investigation provides a feasible simple avenue for development of long-term intrinsic antimicrobial hydrogel dressings with efficient hemostasis efficacy for infected wounds.

Wound and Skin Healing in Space: The 3D Bioprinting Perspective

Skin wound healing is known to be impaired in space. As skin is the tissue mostly at risk to become injured during manned space missions, there is the need for a better understanding of the biological mechanisms behind the reduced wound healing capacity in space. In addition, for far-distant and long-term manned space missions like the exploration of Mars or other extraterrestrial human settlements, e.g., on the Moon, new effective treatment options for severe skin injuries have to be developed. However, these need to be compatible with the limitations concerning the availability of devices and materials present in space missions. Three-dimensional (3D) bioprinting (BP) might become a solution for both demands, as it allows the manufacturing of multicellular, complex and 3D tissue constructs, which can serve as models in basic research as well as transplantable skin grafts. The perspective article provides an overview of the state of the art of skin BP and approach to establish this additive manufacturing technology in space. In addition, the several advantages of BP for utilization in future manned space missions are highlighted.

The role of debridement in wound bed preparation in chronic wound: A narrative review

Objective

To provide an overview of the types of wound debridement and update the available scientific consensus on the effect of wound debridement.

Methods

The articles were searched through CINAHL, PubMed, Cochrane Library, and Medline database for relevant articles on all types of wound debridement. Articles included were all systematic review on the effectiveness of wound debridement-related outcome, published within the year 2017 until Aug 2021, in English.

Results

A total of seven scientific articles had been selected for review out of 318 screened. The authors reviewed a total of 318 titles and abstracts related to wound debridement effectiveness. Seven articles that were selected were narratively reviewed by two authors. The findings of the review were organized into autolytic, enzymatic, sharp, surgical, biological, and mechanical debridement methods and includes the advantages and disadvantages of each. The author further explored on the role of wound debridement according to wound bed preparation model. Articles were synthesized and organized based on the authors, year, total studies included in the systematic review, study range of year, total sample, debridement method, wound types, and findings.

Conclusion

Maggot debridement therapy showed a consistent finding in terms of effectiveness in debriding chronic wounds. The newer debridement method includes hydro-surgery, low-frequency ultrasonic and enzymatic collagenase debridement were getting more attention due to faster wound bed preparation and less painful. However, these newer method of debridements showed inconclusive findings and the patient safety was not clearly defined. A higher level of review is warranted in the future study.

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Maggot debridement therapy (MDT) showed a consistent positive effect in treating chronic wounds.

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New debridement methods that gaining more attention includes hydro-surgery, low-frequency ultrasonic and enzymatic collagenase debridement.

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Newer debridement method reported faster wound bed preparation and deemed to be less pain.

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Patient safety was not clearly defined in these newer debridement methods.

Advances in the use of electrospun nanofibrous polymeric matrix for dermal healing at the donor site after the split-thickness skin graft excision: a prospective, randomized, controlled, open-label, multicenter study

Dressings used to manage donor site wounds have up to 40% of patients experiencing complications that may cause suboptimal scarring. We evaluated the efficacy and safety of a portable electrospun nanofibrous matrix that provides contactless management of donor site wounds compared with standard dressing techniques. This study included adult patients who underwent an excised split-thickness skin graft with a donor site wound area of 10-200 cm 2. Patients were allocated into two groups; i.e., the nanofiber group managed with a nanofibrous polymer-based matrix, and the control group managed using the standard of care such as Jelonet® or Biatain® Ibu dressing. Primary outcomes were postoperative dermal healing efficacy assessed by Draize scores. The time to complete re-epithelialization was also recorded. Secondary outcomes included postoperative adverse events, pain, and infections during the first 21-days and extended 12-month follow-up. The itching and scarring were recorded during the extended follow-up (months 1,3,6,9,12) using Numerical-Analogue-Score and Vancouver scores, respectively. The nanofiber and control groups included 21 and 20 patients, respectively. The Draize dermal irritation scores were significantly lower in the nanofiber vs. control group (Z=-2.509; P=0.028) on the first postoperative day but became similar afterward (Z≥-1.62; P≥0.198). In addition, the average time to re-epithelialization was similar in the nanofiber (17.9±4.4 days) and control group (18.3±4.5 days) (Z=-0.299; P=0.764), so were postoperative adverse events, pain, and infection incidence, itching and scarring. The safety and efficacy of electrospun nanofibrous matrix are similar to standard wound care allowing its use as an alternative donor site dressing following the split-thickness skin graft excision.

Wound Healing with Electrical Stimulation Technologies: A Review

Electrical stimulation (ES) is an attractive field among clinicians in the topic of wound healing, which is common yet complicated and requires multidisciplinary approaches. The conventional dressing and skin graft showed no promise on complete wound closure. These urge the need for the exploration of electrical stimulation to supplement current wound care management. This review aims to provide an overview of electrical stimulation in wound healing. The mechanism of galvanotaxis related to wound repair will be reviewed at the cellular and molecular levels. Meanwhile, different modalities of externally applied electricity mimicking a physiologic electric field will be discussed and compared in vitro, in vivo, and clinically. With the emerging of tissue engineering and regenerative medicine, the integration of electroconductive biomaterials into modern miniaturised dressing is of interest and has become possible with the advancing understanding of smart biomaterials.

Wound-aided semi-solid poly(vinyl alcohol) hydrogels incorporating essential oil-loaded chitosan nanoparticles

The potential of chitosan nanoparticles (CSNPs) loaded with essential oil (EO) incorporated into semi-solid PVA hydrogels for use in wound management was studied. Two types of essential oil were compared including clove essential oil (CEO) and turmeric essential oil (TEO). The EO-loaded CSNPs were prepared by a two-step method; oil-in-water (o/w) emulsification followed by ionic gelation using different ratios of chitosan:EO (i.e., 1:0.25, 1:0.50, 1:0.75, and 1:1.00 w/w). The increasing amount of EO caused more aggregate structure as observed from SEM images. The TEO-loaded CSNPs showed a higher extent of aggregation than the CEO-loaded CSNPs. The adhesiveness of the semi-solid PVA hydrogels containing TEO-loaded CSNPs was the highest. The use of EO-loaded CSNPs in the semi-solid PVA hydrogel helped to sustain and prolong the release rate of EO from the hydrogels as compared to just the EO alone. The studied semi-solid PVA hydrogels were non-toxic to both NCTC clone 929 and NHDF cells. Overall results suggested that these semi-solid hydrogels are good candidates for use in wound management.

Membranous Extracellular Matrix-Based Scaffolds for Skin Wound Healing

Membranous extracellular matrix (ECM)-based scaffolds are one of the most promising biomaterials for skin wound healing, some of which, such as acellular dermal matrix, small intestinal submucosa, and amniotic membrane, have been clinically applied to treat chronic wounds with acceptable outcomes. Nevertheless, the wide clinical applications are always hindered by the poor mechanical properties, the uncontrollable degradation, and other factors after implantation. To highlight the feasible strategies to overcome the limitations, in this review, we first outline the current clinical use of traditional membranous ECM scaffolds for skin wound healing and briefly introduce the possible repair mechanisms; then, we discuss their potential limitations and further summarize recent advances in the scaffold modification and fabrication technologies that have been applied to engineer new ECM-based membranes. With the development of scaffold modification approaches, nanotechnology and material manufacturing techniques, various types of advanced ECM-based membranes have been reported in the literature. Importantly, they possess much better properties for skin wound healing, and would become promising candidates for future clinical translation.

Cotton bandages finished with microcapsules of volatile organic constituents of marine macro-algae for wound healing

Microencapsulation is an innovative technique having a growing application in textile finishing. Besides, marine macroalgae contain plenty of phytoconstituents used in various fields especially textile finishing. This work imparts the property of wound healing finish to cotton fabrics producing a bandage from eco-friendly algal volatile organic constituents (VOCs). VOCs extracted from Digenea simplex, Lurencea papillosa, Galaxurea oblongata, and Turbenaria decurrens Egyptian marine macroalgae scattered along the coastline of the Red sea were 0.52, 0.9, 0.87, and 0.62% (v/w), respectively. These VOCs as well as their microencapsulated (VOM) forms were finished onto cotton fabrics by a conventional pad-dry cure technique using sodium alginate (SA) as a shell wall material. The VOCs of each alga were extracted and chemically investigated using gas chromatography coupled with mass spectrometry (GC-MS). The results indicate, in addition to the identification of 125 volatile compounds, the diversity and outstanding differences in volatile composition among the 4 algae. Wound healing activities of the finished fabrics were evaluated. VOCs microcapsules-finished (VOMF) fabrics were more effective compared to VOCs-finished (VOF) fabrics and almost comparable to mebo-ointment (standard drug)-finished (MoF) fabrics. The differences in VOCs efficiencies may be attributable to the diversity in type and amount of volatiles found in the four algae. Therefore, this is a low-cost, convenient, reproducible, and scalable way to obtain encapsulated VOCs for the application in textile wound healing.

Advances in Skin Wound and Scar Repair by Polymer Scaffolds

Scars, as the result of abnormal wound-healing response after skin injury, may lead to loss of aesthetics and physical dysfunction. Current clinical strategies, such as surgical excision, laser treatment, and drug application, provide late remedies for scarring, yet it is difficult to eliminate scars. In this review, the functions, roles of multiple polymer scaffolds in wound healing and scar inhibition are explored. Polysaccharide and protein scaffolds, an analog of extracellular matrix, act as templates for cell adhesion and migration, differentiation to facilitate wound reconstruction and limit scarring. Stem cell-seeded scaffolds and growth factors-loaded scaffolds offer significant bioactive substances to improve the wound healing process. Special emphasis is placed on scaffolds that continuously release oxygen, which greatly accelerates the vascularization process and ensures graft survival, providing convincing theoretical support and great promise for scarless healing.

Electrospun Medicated Nanofibers for Wound Healing: Review

With the increasing demand for wound care and treatment worldwide, traditional dressings have been unable to meet the needs of the existing market due to their limited antibacterial properties and other defects. Electrospinning technology has attracted more and more researchers' attention as a simple and versatile manufacturing method. The electrospun nanofiber membrane has a unique structure and biological function similar to the extracellular matrix (ECM), and is considered an advanced wound dressing. They have significant potential in encapsulating and delivering active substances that promote wound healing. This article first discusses the common types of wound dressing, and then summarizes the development of electrospun fiber preparation technology. Finally, the polymers and common biologically active substances used in electrospinning wound dressings are summarized, and portable electrospinning equipment is also discussed. Additionally, future research needs are put forward.