Nanomedicine in Healing Chronic Wounds: Opportunities and Challenges

Multifunctional Microneedle Patches Loaded With Engineered Nitric Oxide-Releasing Nanocarriers for Targeted and Synergistic Chronic Wound Therapy

Chronic wounds impose significant physical and mental burdens on patients. Nano-based formulations offer a promising strategy for chronic wound healing due to their non-invasive nature and enhanced biofilms penetration, but they often lack targeting capability or fail to achieve long-term and synergistic effects. In this work, a multifunctional microneedle (MN) patch loaded with engineered nitric oxide (NO)-releasing nanocarriers are presented that encapsulate an antibacterial agent and are immobilized with Concanavalin A (Con A) and NO molecules for targeted and synergistic treatment of chronic wounds. With the assistance of MNs, the nanoparticles (NPs) can directly cross bacterial biofilms and be efficiently delivered to wound tissues, where they target harmful bacteria through the specific recognition between Con A and polysaccharides on bacterial surfaces, followed by the release of the encapsulated antimicrobial agent, thereby achieving effective antibacterial effect. Moreover, the NPs generate NO in a sustained manner as they dissociate in the wound tissue, which exerts potent anti-inflammatory action and benefits tissue regeneration, further promoting chronic wounds closure. Consequently, this work provides a novel MN patch loaded with engineered NPs designed for accelerating chronic wound healing through targeted and synergistic therapy.

Engineering Gas-Releasing Nanomaterials for Efficient Wound Healing

The escalating prevalence of tissue damage and its associated complications has elicited global apprehension. While nanomaterial-based wound healing exhibits significant potential in terms of curbing infections and surpassing conventional methods, unresolved concerns regarding nanomaterial controllability and precision remain unresolved, jeopardizing its practical applications. In recent years, a unique strategy for creating gas-releasing nanomaterials for wound repair has been proposed, involving the creation of gas-releasing nanomaterials to facilitate wound repair by generating gas donor moieties. The operational spatiotemporal responsiveness and broad-spectrum antibacterial properties of these gases, combined with their inability to generate bacterial resistance like traditional antibiotics, establish their efficacy in addressing chronic non-healing wounds, specifically diabetic foot ulcers (DFUs). In this review, we delve into the intricacies of wound healing process, emphasizing the chemical design, functionality, bactericidal activity, and potential of gas-release materials, encompassing NO, CO, H2S, O2, CO2, and H2, for effective wound healing. Furthermore, we explore the advancements in synergistic therapy utilizing these gases, aiming to enhance our overall comprehension of this field. The insights gleaned from this review will undoubtedly aid researchers and developers in the creation of promising gas-releasing nanomaterials, thus propelling efficient wound healing in the future.

Sulfated Galactan Derivative from Gracilaria fisheri Improves Histopathology and Alters Wound Healing-Related Proteins in the Skin of Excision Rats

BACKGROUND

The biological activities of sulfated polysaccharides (SP) are well-documented, especially regarding wound healing. Sulfated galactan (SG), a type of SP extracted from the red seaweed Gracilaria fisheri, has been identified as having multiple therapeutic properties related to its wound healing capacity. Recent research indicates that degraded SG (DSG) from G. fisheri, when combined with octanoyl ester (DSGO), can improve wound healing in fibroblasts. However, the effectiveness of natural products in clinical settings often differs from in vitro results. This study aimed to develop and evaluate ointments containing DSG and DSGO for skin repair in an animal model.

METHODS

Twenty-four Wistar rats were divided into four groups: (1) normal control, (2) ointment control, (3) DSG ointment, and (4) DSGO ointment. After inducing full-thickness excision wounds, these ointments were applied to the wounds. Wound contraction rate, histopathology, and protein related wound healing expression were then elucidated.

RESULTS

Our findings showed that both DSG and DSGO ointments significantly enhanced wound closure compared to the control groups. Histopathological and biochemical analyses indicated increased extracellular matrix production and fibroblasts, marked by improved fibroblast activity, neovascularization, and collagen deposition. Furthermore, immunohistochemistry and immunoblot analysis revealed that the ointments altered the expression of Ki67, α-smooth muscle actin (α-SMA), E-cadherin, vimentin, collagen, and components of the Smad signaling pathway, all of which are crucial for wound healing. The results also suggested that the DSGO ointment was marginally more effective in promoting wound healing in this model.

CONCLUSIONS

These results indicate that ointment supplemented with DSG and DSGO have the potential to enhance skin repair by improving histopathology and altering wound healing-related proteins.

Oxygen-Bonded Amorphous Transition Metal Dichalcogenides with pH-Responsive Reactive Oxygen Biocatalysis for Combined Antibacterial and Anti-inflammatory Therapies in Diabetic Wound Healing

Diabetic wound healing is a formidable challenge, often complicated by biofilms, immune dysregulation, and hindered vascularization within the wound environments. The intricate interplay of these microenvironmental factors has been a significant oversight in the evolution of therapeutic strategies. Herein, the design of an efficient and versatile oxygen-bonded amorphous transition metal dichalcogenide biocatalyst (aRuS-Or) with pH-responsive reactive oxygen biocatalysis for combined antibacterial and anti-inflammatory therapies in promoting diabetic wound healing is reported. Leveraging the incorporation of Ru─O bonds, aRuS-Or exhibits optimized adsorption/desorption behavior of oxygen intermediates, thereby enhancing both the reactive oxygen species (ROS) generation activity in acidic conditions and ROS scavenging performance in neutral environments. Remarkably, aRuS-Or demonstrates exceptional bactericidal potency within infected milieus through biocatalytic ROS generation. Beyond its antimicrobial capability, post-eradication, aRuS-Or serves a dual role in mitigating oxidative stress in inflammatory wounds, providing robust cellular protection and fostering an M2-phenotype polarization of macrophages, which is pivotal for accelerating the wound repair process. The findings underscore the multifaceted efficacy of aRuS-Or, which harmoniously integrates high antibacterial action with anti-inflammatory and pro-angiogenic properties. This triad of functionalities positions aRuS-Or as a promising candidate for the comprehensive management of complex diabetic ulcers, addressing the unmet needs in the current therapeutics.

Advancements in wound management: integrating nanotechnology and smart materials for enhanced therapeutic interventions

Wound management spans various techniques and materials tailored to address acute and chronic non-healing wounds, with the primary objective of achieving successful wound closure. Chronic wounds pose additional challenges, often necessitating dressings to prepare the wound bed for subsequent surgical procedures like skin grafting. Ideal dressing materials should not only expedite wound healing but also mitigate protein, electrolyte, and fluid loss while minimizing pain and infection risk. Nanotechnology has emerged as a transformative tool in wound care, revolutionizing the landscape of biomedical dressings. Its application offers remarkable efficacy in accelerating wound healing and combating bacterial infections, representing a significant advancement in wound care practices. Integration of nanotechnology into dressings has resulted in enhanced properties, including improved mechanical strength and controlled drug release, facilitating tailored therapeutic interventions. This review article comprehensively explores recent breakthroughs in wound healing therapies, with a focus on innovative medical dressings such as nano-enzymes. Additionally, the utilization of smart materials, like hydrogels and electroactive polymers, in wound dressings offers dynamic functionalities to promote tissue regeneration. Emerging concepts such as bio-fabrication, microfluidic systems, bio-responsive scaffolds, and personalized therapeutics show promise in expediting wound healing and minimizing scarring. Through an in-depth exploration of these advancements, this review aims to catalyze a paradigm shift in wound care strategies, promoting a patient-centric approach to therapeutic interventions.

Tailoring silk fibroin fibrous architecture by a high-yield electrospinning method for fast wound healing possibilities

In this study, a novel array electrospinning collector was devised to generate two distinct regenerated silk fibroin (SF) fibrous membranes: ordered and disordered. Leveraging electrostatic forces during the electrospinning process allowed precise control over the orientation of SF fiber, resulting in the creation of membranes comprising both aligned and randomly arranged fiber layers. This innovative approach resulted in the development of large-area membranes featuring exceptional stability due to their alternating patterned structure, achievable through expansion using the collector, and improving the aligned fiber membrane mechanical properties. The study delved into exploring the potential of these membranes in augmenting wound healing efficiency. Conducting in vitro toxicity assays with adipose tissue-derived mesenchymal stem cells (AD-MSCs) and normal human dermal fibroblasts (NHDFs) confirmed the biocompatibility of the SF membranes. We use dual perspectives on exploring the effects of different conditioned mediums produced by cells and structural cues of materials on NHDFs migration. The nanofibers providing the microenvironment can directly guide NHDFs migration and also affect the AD-MSCs and NHDFs paracrine effects, which can improve the chemotaxis of NHDFs migration. The ordered membrane, in particular, exhibited pronounced effectiveness in guiding directional cell migration. This research underscores the revelation that customizable microenvironments facilitated by SF membranes optimize the paracrine products of mesenchymal stem cells and offer valuable physical cues, presenting novel prospects for enhancing wound healing efficiency.

Chitosan-based self-healing hydrogel dressing for wound healing

Skin has strong self-regenerative capacity, while severe skin defects do not heal without appropriate treatment. Therefore, in order to cover the wound sites and hasten the healing process, wound dressings are required. Hydrogels have emerged as one of the most promising candidates for wound dressings because of their hydrated and porous molecular structure. Chitosan (CS) with biocompatibility, oxygen permeability, hemostatic and antimicrobial properties is beneficial for wound treatment and it can generate self-healing hydrogels through reversible crosslinks, from dynamic covalent bonding, such as Schiff base bonds, boronate esters, and acylhydrazone bonds, to physical interactions like hydrogen bonding, electrostatic interaction, ionic bonding, metal-coordination, host-guest interactions, and hydrophobic interaction. Therefore, various chitosan-based self-healing hydrogel dressings have been prepared in recent years to cope with increasingly complex wound conditions. This review's objective is to provide comprehensive information on the self-healing mechanism of chitosan-based hydrogel wound dressings, discuss their advanced functions including antibacterial, conductive, anti-inflammatory, anti-oxidant, stimulus-responsive, hemostatic/adhesive and controlled release properties, further introduce their applications in the promotion of wound healing in two categories: acute and chronic (infected, burn and diabetic) wounds, and finally discuss the future perspective of chitosan-based self-healing hydrogel dressings for wound healing.

Novel Sprayable Antioxidative Dressing Based on Fullerene and Curdlan for Accelerating Chronic Wound Healing

The effective treatment of chronic wounds represents a critical global medical challenge demanding urgent attention. Persistent inflammation, driven by an excess of reactive oxygen radicals, sets in motion a detrimental cycle leading to chronic wounds and impeding the natural healing process. This study develops a sprayable wound dressing by covalently grafting amino fullerene to carboxymethylated curdlan (CMC-C). This novel dressing exhibits excellent biocompatibility, antioxidant, and reactive oxygen species scavenging properties. Furthermore, it demonstrates a targeted affinity for HEK-a cells, efficiently reducing the inflammatory response while promoting cell proliferation and migration in vitro. Moreover, the animal experiment investigations reveal that CMC-C significantly accelerates chronic wounds healing by regulating the inflammatory process, promoting collagen deposition, and improving vascularization. These results demonstrate the potential of the sprayable dressing (CMC-C) in curing the healing of chronic wounds through the modulation of the inflammatory microenvironment. Overall, the sprayable hydrogel dressing based on water-soluble derivative of fullerene and curdlan emerges as a potential approach for clinical applications in the treatment of chronic wounds.

Emerging Nanotherapeutic Approaches for Diabetic Wound Healing

Diabetic wounds pose a significant challenge in modern healthcare due to their chronic and complex nature, often resulting in delayed healing, infections, and, in severe cases, amputations. In recent years, nanotherapeutic approaches have emerged as promising strategies to address the unique pathophysiological characteristics of diabetic wounds. This review paper provides a comprehensive overview of the latest advancements in nanotherapeutics for diabetic wound treatment. We discuss various nanomaterials and delivery systems employed in these emerging therapies. Furthermore, we explore the integration of biomaterials to enhance the efficacy of nanotherapeutic interventions. By examining the current state-of-the-art research, challenges, and prospects, this review aims to offer valuable insights for researchers, clinicians, and healthcare professionals working in the field of diabetic wound care.

Design and synthesis of a nucleobase functionalized peptide hydrogel: in vitro assessment of anti-inflammatory and wound healing effects

Over the past several years, a significant increase in the expanding field of biomaterial sciences has been observed due to the development of biocompatible materials based on peptide derivatives that have intrinsic therapeutic potential. In this report, we synthesized nucleobase functionalized peptide derivatives (NPs). Hydrogelation in the synthesized NPs was induced by increasing their hydrophobicity with an aromatic moiety. The aggregation behavior of the NPs was analyzed by performing molecular dynamics simulations and DOSY NMR experiments. We performed circular dichroism (CD), thioflavin-T binding and PXRD to characterize the supramolecular aggregation in the NP1 hydrogel. The mechanical strength of the NP1 hydrogel was tested by performing rheological experiments. TEM and SEM experiments were performed to investigate the morphology of the NP1 hydrogel. The biocompatibility of the newly synthesized NP1 hydrogel was investigated using McCoy and A549 cell lines. The hemolytic activity of the NP1 hydrogel was examined in human blood cells. The stability of the newly formed NP1 hydrogel was examined using proteinase K and α-chymotrypsin. The NP1 hydrogel was used for in vitro wound healing. Western blotting, qRT-PCR and DCFDA assay were performed to determine the anti-inflammatory activity of the NP1 hydrogel. The synthesized NP1 hydrogel also exhibits antibacterial efficacy.

Design Strategy of Microneedle Systems for Skin Wound Healing: Based on the Structure of Tips and Therapeutic Methodologies

The skin, being the largest organ of the human body, is susceptible to damage resulting in wounds that are vulnerable to pathogenic attacks and fail to provide effective protection for internal tissues. Therefore, it is crucial to expedite wound healing. In recent years, microneedles have garnered significant attention as an innovative drug delivery system owing to their noninvasive and painless administration, simplified application process, precise control over drug release, and versatile loading capabilities. Consequently, they hold immense potential for the treatment of skin wound. This review presents a comprehensive design strategy for the microneedle system in promoting skin wound healing. First, the process of skin wound healing and the characteristics of specific wounds are elucidated. The design strategies for microneedles are subsequently presented and classified based on their structural and therapeutic methodologies. Finally, a succinct recapitulation of the previously discussed points and a prospective analysis are provided.

Nanomaterial strategies in wound healing: A comprehensive review of nanoparticles, nanofibres and nanosheets

Wound healing is a complex process that orchestrates the coordinated action of various cells, cytokines and growth factors. Nanotechnology offers exciting new possibilities for enhancing the healing process by providing novel materials and approaches to deliver bioactive molecules to the wound site. This article elucidates recent advancements in utilizing nanoparticles, nanofibres and nanosheets for wound healing. It comprehensively discusses the advantages and limitations of each of these materials, as well as their potential applications in various types of wounds. Each of these materials, despite sharing common properties, can exhibit distinct practical characteristics that render them particularly valuable for healing various types of wounds. In this review, our primary focus is to provide a comprehensive overview of the current state-of-the-art in applying nanoparticles, nanofibres, nanosheets and their combinations to wound healing, serving as a valuable resource to guide researchers in their appropriate utilization of these nanomaterials in wound-healing research. Further studies are necessary to gain insight into the application of this type of nanomaterials in clinical settings.

Plant-Derived Exosomes as Novel Nanotherapeutics Contrive Glycolysis Reprogramming-Mediated Angiogenesis for Diabetic Ulcer Healing

Reversal of endothelial cell (EC) dysfunction under high-glucose (HG) conditions to achieve angiogenesis has remained a big challenge in diabetic ulcers. Herein, exosomes derived from medicinal plant ginseng (GExos) were shown as excellent nanotherapeutics with biomimetic cell membrane-like structures to be able to efficiently transfer the encapsulated active substances to ECs, resulting in a marked reprogramming of glycolysis by up-regulating anaerobic glycolysis and down-regulating oxidative stress, which further restore the proliferation, migration, and tubule formation abilities of ECs under HG conditions. In vivo, GExos enhance the angiogenesis and nascent vessel network reconstruction in full-thickness diabetic complicated skin ulcer wounds in mice with high biosafety. GExos were shown as promising nanotherapeutics in stimulating glycolysis reprogramming-mediated angiogenesis in diabetic ulcers, possessing wide application potential for reversing hyperglycemic dysangiogenesis and stimulating vascular regeneration.

A critical overview of challenging roles of medicinal plants in improvement of wound healing technology

PURPOSE

Chronic diseases often hinder the natural healing process, making wound infections a prevalent clinical concern. In severe cases, complications can arise, potentially leading to fatal outcomes. While allopathic treatments offer numerous options for wound repair and management, the enduring popularity of herbal medications may be attributed to their perceived minimal side effects. Hence, this review aims to investigate the potential of herbal remedies in efficiently treating wounds, presenting a promising alternative for consideration.

METHODS

A literature search was done including research, reviews, systematic literature review, meta-analysis, and clinical trials considered. Search engines such as Pubmed, Google Scholar, and Scopus were used while retrieving data. Keywords like Wound healing 'Wound healing and herbal combinations', 'Herbal wound dressing', Nanotechnology and Wound dressing were used.

RESULT

This review provides valuable insights into the role of natural products and technology-based formulations in the treatment of wound infections. It evaluates the use of herbal remedies as an effective approach. Various active principles from herbs, categorized as flavonoids, glycosides, saponins, and phenolic compounds, have shown effectiveness in promoting wound closure. A multitude of herbal remedies have demonstrated significant efficacy in wound management, offering an additional avenue for care. The review encompasses a total of 72 studies, involving 127 distinct herbs (excluding any common herbs shared between studies), primarily belonging to the families Asteraceae, Fabaceae, and Apiaceae. In research, rat models were predominantly utilized to assess wound healing activities. Furthermore, advancements in herbal-based formulations using nanotechnology-based wound dressing materials, such as nanofibers, nanoemulsions, nanofiber mats, polymeric fibers, and hydrogel-based microneedles, are underway. These innovations aim to enhance targeted drug delivery and expedite recovery. Several clinical-based experimental studies have already been documented, evaluating the efficacy of various natural products for wound care and management. This signifies a promising direction in the field of wound treatment.

CONCLUSION

In recent years, scientists have increasingly utilized evidence-based medicine and advanced scientific techniques to validate the efficacy of herbal medicines and delve into the underlying mechanisms of their actions. However, there remains a critical need for further research to thoroughly understand how isolated chemicals extracted from herbs contribute to the healing process of intricate wounds, which may have life-threatening consequences. This ongoing research endeavor holds great promise in not only advancing our understanding but also in the development of innovative formulations that expedite the recovery process.

Rutin-loaded zein gel as a green biocompatible formulation for wound healing application

Wound healing is a challenging clinical problem and efficient wound management is essential to prevent infection. This is best done by utilizing biocompatible materials in order to complete the healing in a rapid manner, with functional and esthetic outcomes. In this context, the zein protein fulfills the criteria of the ideal wound dressing which include non-toxicity and non-inflammatory stimulation. Zein gels containing rutin were prepared without any chemical refinement or addition of gelling agents in order to obtain a natural formulation characterized by antioxidant and anti-inflammatory properties to be proposed for the treatment of burns and sores. In vitro scratch assay showed that the proposed gel formulations promoted cell migration and a rapid gap closure within 24 h (~90 %). In addition, the in vivo activities of rutin-loaded zein gel showed a greater therapeutic efficacy in Wistar rats, with a decrease of the wound area of about 90 % at day 10 with respect to the free form of the bioactive and to DuoDERM®. The evaluation of various markers (TNF-α, IL-1β, IL-6, IL-10) confirmed the anti-inflammatory effect of the proposed formulation. The results illustrate the feasibility of exploiting the peculiar features of rutin-loaded zein gels for wound-healing purposes.

Growth factors and growth factor gene therapies for treating chronic wounds

Chronic wounds are an unmet clinical need affecting millions of patients globally, and current standards of care fail to consistently promote complete wound closure and prevent recurrence. Disruptions in growth factor signaling, a hallmark of chronic wounds, have led researchers to pursue growth factor therapies as potential supplements to standards of care. Initial studies delivering growth factors in protein form showed promise, with a few formulations reaching clinical trials and one obtaining clinical approval. However, protein-form growth factors are limited by instability and off-target effects. Gene therapy offers an alternative approach to deliver growth factors to the chronic wound environment, but safety concerns surrounding gene therapy as well as efficacy challenges in the gene delivery process have prevented clinical translation. Current growth factor delivery and gene therapy approaches have primarily used single growth factor formulations, but recent efforts have aimed to develop multi-growth factor approaches that are better suited to address growth factor insufficiencies in the chronic wound environment, and these strategies have demonstrated improved efficacy in preclinical studies. This review provides an overview of chronic wound healing, emphasizing the need and potential for growth factor therapies. It includes a summary of current standards of care, recent advances in growth factor, cell-based, and gene therapy approaches, and future perspectives for multi-growth factor therapeutics.

Mussel‐Inspired Recombinant Adhesive Protein‐Based Functionalization for Consistent and Effective Antimicrobial Treatment in Chronic Inflammatory Skin Diseases

Chronic inflammatory skin diseases, characterized by a vicious cycle of infection and hyperinflammation, necessitate consistent and effective antimicrobial treatment of target lesions to achieve practical therapeutic outcomes. Antimicrobial dressing materials offer notable advantages over conventional therapeutic drugs, including ease of application, extended contact time, and targeted antimicrobial action, resulting in enhanced efficacy in breaking the vicious cycle. In line with these advantages, this study aims to develop a plug‐and‐playable recombinant adhesive protein (RAP) inspired by the adhesive properties of marine mussels, serving as a durable and effective surface functionalization strategy. By genetically recombining mussel foot protein with antimicrobial peptides, RAP effectively incorporates antimicrobial properties into biomaterials for treating chronic inflammatory skin diseases. The durable adhesion of RAP ensures long‐lasting antimicrobial functionality on target surfaces, MFP making it a promising approach to inhibit chronic inflammation. In addition, when dip‐coated onto cotton gauze, RAP can be utilized as an antimicrobial patch, effectively suppressing chronic inflammation through the inhibition of bacteria‐induced toll‐like receptor signaling. These findings underscore the potential of nature‐inspired protein‐based surface functionalization of biomaterials as a compelling approach to advance the treatment of chronic inflammatory skin diseases.

Sustainable whey proteins-nanostructured zinc oxide-based films for the treatment of chronic wounds: New insights from biopharmaceutical studies

Chronic wounds represent silent epidemic affecting a large portion of the world population, especially the elders; in this context, the development of advanced bioactive dressings is imperative to accelerate wound healing process, while contrasting or preventing infections. The aim of the present work was to provide a deep characterization of the functional and biopharmaceutical properties of a sustainable thin and flexible films, composed of whey proteins alone (WPI) and added with nanostructured zinc oxide (WPZ) and intended for the management of chronic wounds. The potential of whey proteins-based films as wound dressings has been confirmed by their wettability, hydration properties, elastic behavior upon hydration, biodegradation propensity and, when added with nanostructured zinc oxide, antibacterial efficacy against both Gram-positive and Gram-negative pathogens, i.e. Staphylococcus aureus and Escherichia coli. In-vitro experiments, performed on normal human dermal fibroblasts, confirmed film cytocompatibility, also revealing the possible role of Zn2+ ions in promoting fibroblast proliferation. Finally, in-vivo studies on rat model confirmed film suitability to act as wound dressing, since able to ensure a regular healing process while providing effective protection from infections. In particular, both films WPI and WPZ are responsible for the formation in the wound bed of a continuous collagen layer similar to that of healthy skin.

Green synthesis of epigallocatechin gallate-ferric complex nanoparticles for photothermal enhanced antibacterial and wound healing

Bacterial infections are a significant global health concern, particularly in the context of skin infections and chronic wounds, which was further exacerbated by the emerging of antibiotic resistance. Therefore, there are urgent needs to develop alternative antibacterial strategies without inducing significant resistance. Photothermal therapy (PTT) is a promising alternative approach but usually faces limitations such as the need for stable and environmental-friendly PTT agents and ensuring biocompatibility with living tissues, necessitating ongoing research for its clinical advancement. Herein, in this study, with the aim to develop a green synthesized PTT agent for photothermal enhanced antibacterial and wound healing, we proposed a facile one-pot method to prepare epigallocatechin gallate-ferric (EGCG-Fe) complex nanoparticles. The obtained nanoparticles showed improved good size distribution and stability with high reproducibility. More importantly, EGCG-Fe complex nanoparticles have additional photothermal conversion ability which can give photothermal enhanced antibacterial effect on various pathogens, including Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) strains. EGCG-Fe complex nanoparticles also showed powerful biofilm prevention and destruction effects with promoted antibacterial and wound healing on mice model. In conclusion, EGCG-Fe complex nanoparticles can be a robust green material with effective and novel light controllable antibacterial properties for photothermal enhanced antibacterial and wound healing applications.

ROS-responsive hydrogels with spatiotemporally sequential delivery of antibacterial and anti-inflammatory drugs for the repair of MRSA-infected wounds

For the treatment of MRSA-infected wounds, the spatiotemporally sequential delivery of antibacterial and anti-inflammatory drugs is a promising strategy. In this study, ROS-responsive HA-PBA/PVA (HPA) hydrogel was prepared by phenylborate ester bond cross-linking between hyaluronic acid-grafted 3-amino phenylboronic acid (HA-PBA) and polyvinyl alcohol (PVA) to achieve spatiotemporally controlled release of two kinds of drug to treat MRSA-infected wound. The hydrophilic antibiotic moxifloxacin (M) was directly loaded in the hydrogel. And hydrophobic curcumin (Cur) with anti-inflammatory function was first mixed with Pluronic F127 (PF) to form Cur-encapsulated PF micelles (Cur-PF), and then loaded into the HPA hydrogel. Due to the different hydrophilic and hydrophobic nature of moxifloxacin and Cur and their different existing forms in the HPA hydrogel, the final HPA/M&Cur-PF hydrogel can achieve different spatiotemporally sequential delivery of the two drugs. In addition, the swelling, degradation, self-healing, antibacterial, anti-inflammatory, antioxidant property, and biocompatibility of hydrogels were tested. Finally, in the MRSA-infected mouse skin wound, the hydrogel-treated group showed faster wound closure, less inflammation and more collagen deposition. Immunofluorescence experiments further confirmed that the hydrogel promoted better repair by reducing inflammation (TNF-α) and promoting vascular (VEGF) regeneration. In conclusion, this HPA/M&Cur-PF hydrogel that can spatiotemporally sequential deliver antibacterial and anti-inflammatory drugs showed great potential for the repair of MRSA-infected skin wounds.

Alginate/gum arabic-based biomimetic hydrogel enriched with immobilized nerve growth factor and carnosine improves diabetic wound regeneration

Diabetic foot ulcers (DFUs) often remain untreated because they are difficult to heal, caused by reduced skin sensitivity and impaired blood vessel formation. In this study, we propose a novel approach to manage DFUs using a multifunctional hydrogel made from a combination of alginate and gum arabic. To enhance the healing properties of the hydrogel, we immobilized nerve growth factor (NGF), within specially designed mesoporous silica nanoparticles (MSN). The MSNs were then incorporated into the hydrogel along with carnosine (Car), which further improves the hydrogel's therapeutic properties. The hydrogel containing the immobilized NGF (SiNGF) could control the sustain release of NGF for >21 days, indicating that the target hydrogel (AG-Car/SiNGF) can serve as a suitable reservoir managing diabetic wound regeneration. In addition, Car was able to effectively reduce inflammation and significantly increase angiogenesis compared to the control group. Based on the histological results obtained from diabetic rats, the target hydrogel (AG-Car/SiNGF) reduced inflammation and improved re-epithelialization, angiogenesis, and collagen deposition. Specific staining also confirmed that AG-Car/SiNGF exhibited improved tissue neovascularization, transforming growth factor-beta (TGFβ) expression, and nerve neurofilament. Overall, our research suggests that this newly developed composite system holds promise as a potential treatment for non-healing diabetic wounds.

Metal-Phenolic Networks for Chronic Wounds Therapy

Chronic wounds are recalcitrant complications of a variety of diseases, with pathologic features including bacterial infection, persistent inflammation, and proliferation of reactive oxygen species (ROS) levels in the wound microenvironment. Currently, the use of antimicrobial drugs, debridement, hyperbaric oxygen therapy, and other methods in clinical for chronic wound treatment is prone to problems such as bacterial resistance, wound expansion, and even exacerbation. In recent years, researchers have proposed many novel materials for the treatment of chronic wounds targeting the disease characteristics, among which metal-phenolic networks (MPNs) are supramolecular network structures that utilize multivalent metal ions and natural polyphenols complexed through ligand bonds. They have a flexible and versatile combination of structural forms and a variety of formations (nanoparticles, coatings, hydrogels, etc.) that can be constructed. Functionally, MPNs combine the chemocatalytic and bactericidal properties of metal ions as well as the anti-inflammatory and antioxidant properties of polyphenol compounds. Together with the excellent properties of rapid synthesis and negligible cytotoxicity, MPNs have attracted researchers' great attention in biomedical fields such as anti-tumor, anti-bacterial, and anti-inflammatory. This paper will focus on the composition of MPNs, the mechanisms of MPNs for the treatment of chronic wounds, and the application of MPNs in novel chronic wound therapies.

Photothermal antibacterial materials to promote wound healing

Wound healing is a crucial process that restores the integrity and function of the skin and other tissues after injury. However, external factors, such as infection and inflammation, can impair wound healing and cause severe tissue damage. Therefore, developing new drugs or methods to promote wound healing is of great significance. Photothermal therapy (PTT) is a promising technique that uses photothermal agents (PTAs) to convert near-infrared radiation into heat, which can eliminate bacteria and stimulate tissue regeneration. PTT has the advantages of high efficiency, controllability, and low drug resistance. Hence, nanomaterial-based PTT and its related strategies have been widely explored for wound healing applications. However, a comprehensive review of PTT-related strategies for wound healing is still lacking. In this review, we introduce the physiological mechanisms and influencing factors of wound healing, and summarize the types of PTAs commonly used for wound healing. Then, we discuss the strategies for designing nanocomposites for multimodal combination treatment of wounds. Moreover, we review methods to improve the therapeutic efficacy of PTT for wound healing, such as selecting the appropriate wound dressing form, controlling drug release, and changing the infrared irradiation window. Finally, we address the challenges of PTT in wound healing and suggest future directions.

Accelerated Wound Healing with a Diminutive Scar through Cocrystal Engineered Curcumin

Pharmaceutical cocrystals ( Regulatory Classification of Pharmaceutical Co-Crystals Guidance for Industry; Food and Drug Administration, 2018) are crystalline solids produced through supramolecular chemistry to modulate the physicochemical properties of active pharmaceutical ingredients (APIs). Despite their extensive development in interdisciplinary sciences, this is a pioneering study on the efficacy of pharmaceutical cocrystals in wound healing and scar reducing. Curcumin-pyrogallol cocrystal (CUR-PYR) was accordingly cherry-picked since its superior physicochemical properties adequately compensate for limitative drawbacks of curcumin (CUR). CUR-PYR has been synthesized by a liquid-assisted grinding (LAG) method and characterized via FT-IR, DSC, and PXRD analyses. In vitro antibacterial study indicated that CUR-PYR cocrystal, CUR+PYR physical mixture (PM), and PYR are more effective against both Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria in comparison with CUR. In vitro results also demonstrated that the viability of HDF and NIH-3T3 cells treated with CUR-PYR were improved more than those received CUR which is attributed to the effect of PYR in the form of cocrystal. The wound healing process has been monitored through a 15 day in vivo experiment on 75 male rats stratified into six groups: five groups treated by CUR-PYR+Vaseline (CUR-PYR.ung), CUR+PYR+Vaseline (CUR+PYR.ung), CUR+Vaseline (CUR.ung), PYR+Vaseline (PYR.ung), and Vaseline (VAS) ointments and a negative control group of 0.9% sodium chloride solution (NS). It was revealed that the wounds under CUR-PYR.ung treatment closed by day 12 postsurgery, while the wounds in other groups failed to reach the complete closure end point until the end of the experiment. Surprisingly, a diminutive scar (3.89 ± 0.97% of initial wound size) was observed in the CUR-PYR.ung treated wounds by day 15 after injury, followed by corresponding values for PYR.ung (12.08 ± 2.75%), CUR+PYR.ung (13.89 ± 5.02%), CUR.ung (16.24 ± 6.39%), VAS (18.97 ± 6.89%), and NS (20.33 ± 5.77%). Besides, investigating histopathological parameters including inflammation, granulation tissue, re-epithelialization, and collagen deposition signified outstandingly higher ability of CUR-PYR cocrystal in wound healing than either of its two constituents separately or their simple PM. It was concluded that desired solubility of the prepared cocrystal was essentially responsible for accelerating wound closure and promoting tissue regeneration which yielded minimal scarring. This prototype research suggests a promising application of pharmaceutical cocrystals for the purpose of wound healing.

Electrospun polyvinyl alcohol-chitosan dressing stimulates infected diabetic wound healing with combined reactive oxygen species scavenging and antibacterial abilities

Diabetic wounds (DW) are constantly challenged by excessive reactive oxygen species (ROS) accumulation and susceptibility to bacterial contamination. Therefore, the elimination of ROS in the immediate vicinity and the eradication of local bacteria are critical to stimulating the efficient healing of diabetic wounds. In the current study, we encapsulated mupirocin (MP) and cerium oxide nanoparticles (CeNPs) into a polyvinyl alcohol/chitosan (PVA/CS) polymer, and then a PVA/chitosan nanofiber membrane wound dressing was fabricated using electrostatic spinning, which is a simple and efficient method for fabricating membrane materials. The PVA/chitosan nanofiber dressing provided a controlled release of MP, which produced rapid and long-lasting bactericidal activity against both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains. Simultaneously, the CeNPs embedded in the membrane exhibited the desired ROS scavenging capacity to maintain the local ROS at a normal physiological level. Moreover, the biocompatibility of the multifunctional dressing was evaluated both in vitro and in vivo. Taken together, PVA-CS-CeNPs-MP integrated the desirable features of a wound dressing, including rapid and broad-spectrum antimicrobial and ROS scavenging activities, easy application, and good biocompatibility. The results validated the effectiveness of our PVA/chitosan nanofiber dressing, highlighting its promising translational potential in the treatment of diabetic wounds.

Emerging Applications of Nanotechnology in Healthcare and Medicine

Knowing the beneficial aspects of nanomedicine, scientists are trying to harness the applications of nanotechnology in diagnosis, treatment, and prevention of diseases. There are also potential uses in designing medical tools and processes for the new generation of medical scientists. The main objective for conducting this research review is to gather the widespread aspects of nanomedicine under one heading and to highlight standard research practices in the medical field. Comprehensive research has been conducted to incorporate the latest data related to nanotechnology in medicine and therapeutics derived from acknowledged scientific platforms. Nanotechnology is used to conduct sensitive medical procedures. Nanotechnology is showing successful and beneficial uses in the fields of diagnostics, disease treatment, regenerative medicine, gene therapy, dentistry, oncology, aesthetics industry, drug delivery, and therapeutics. A thorough association of and cooperation between physicians, clinicians, researchers, and technologies will bring forward a future where there is a more calculated, outlined, and technically programed field of nanomedicine. Advances are being made to overcome challenges associated with the application of nanotechnology in the medical field due to the pathophysiological basis of diseases. This review highlights the multipronged aspects of nanomedicine and how nanotechnology is proving beneficial for the health industry. There is a need to minimize the health, environmental, and ethical concerns linked to nanotechnology.

Basic research and clinical exploration of cold atmospheric plasma for skin wounds

Skin wounds, such as burns, diabetic foot ulcers, pressure sores, and wounds formed after laser or surgical treatment, comprise a very high proportion of dermatological disorders. Wounds are treated in a variety of ways; however, some wounds are greatly resistant, resulting in delayed healing and an urgent need to introduce new alternatives. Our previous studies have shown that cold atmospheric plasma (CAP) has antibacterial activity and promotes cell proliferation, differentiation, and migration in vitro. To further advance the role of CAP in wound healing, we evaluated the safety and efficacy of CAP in vitro by irradiation of common refractory bacteria on the skin, irradiation of normal skin of rats and observing reactions, treatment of scald wounds in rats, and treating clinically common acute wounds. Our findings revealed that CAP can eliminate refractory skin bacteria in vitro; CAP positively affected wound healing in a rat scalding wound model; and direct CAP irradiation of low intensity and short duration did not lead to skin erythema or edema. CAP promises to be a new, economical, and safe means of wound treatment.

Mesoporous Composite Bioactive Compound Delivery System for Wound-Healing Processes

Currently, the treatment of wounds is still a challenge for healthcare professionals due to high complication incidences and social impacts, and the development of biocompatible and efficient medicines remains a goal. In this regard, mesoporous materials loaded with bioactive compounds from natural extracts have a high potential for wound treatment due to their nontoxicity, high loading capacity and slow drug release. MCM-41-type mesoporous material was synthesized by using sodium trisilicate as a silica source at room temperature and normal pressure. The synthesized mesoporous silica was characterized by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), N2 absorption-desorption (BET), Dynamic Light Scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR), revealing a high surface area (BET, 1244 m2/g); pore diameter of approx. 2 nm; and a homogenous, ordered and hexagonal geometry (TEM images). Qualitative monitoring of the desorption degree of the Salvia officinalis (SO) extract, rich in ursolic acid and oleanolic acid, and Calendula officinalis (CO) extract, rich in polyphenols and flavones, was performed via the continuous recording of the UV-VIS spectra at predetermined intervals. The active ingredients in the new composite MCM-41/sage and marigold (MCM-41/SO&CO) were quantified by using HPLC-DAD and LC-MS-MS techniques. The evaluation of the biological composites' activity on the wound site was performed on two cell lines, HS27 and HaCaT, naturally involved in tissue-regeneration processes. The experimental results revealed the ability to stimulate collagen biosynthesis, the enzymatic activity of the main metalloproteinases (MMP-2 and MMP-9) involved in tissue remodeling processes and the migration rate in the wound site, thus providing insights into the re-epithelializing properties of mesoporous composites.

Multidrug-Resistant Pathogens in Burn Wound, Prevention, Diagnosis, and Therapeutic Approaches (Conventional Antimicrobials and Nanoparticles)

Multidrug-resistant pathogens are one of the common causes of death in burn patients and have a high risk of nosocomial infections, especially pneumonia, urinary tract infections, and cellulitis. The role of prolonged hospitalization and empirical antibiotics administration in developing multidrug-resistant pathogens is undeniable. In the early days of admitting burn patients, Gram-positive bacteria were the dominant isolates with a more sensitive antibiotic pattern. However, the emergence of Gram-negative bacteria that are more resistant later occurs. Trustworthy guideline administration in burn wards is one of the strategies to prevent multidrug-resistant pathogens. Also, a multidisciplinary therapeutic approach is an effective way to avoid antibiotic resistance that involves infectious disease specialists, pharmacists, and burn surgeons. However, the emerging resistance to conventional antimicrobial approaches (such as systemic antibiotic exposure, traditional wound dressing, and topical antibiotic ointments) among burn patients has challenged the treatment of multidrug-resistant infections, and using nanoparticles is a suitable alternative. In this review article, we will discuss different aspects of multidrug-resistant pathogens in burn wounds, emphasizing the full role of these pathogens in burn wounds and discussing the application of nanotechnology in dealing with them. Also, some advances in various types of nanomaterials, including metallic nanoparticles, liposomes, hydrogels, carbon quantum dots, and solid lipid nanoparticles in burn wound healing, will be explained.

Polymer-Based Wound Dressings Loaded with Ginsenoside Rg3

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

Composite nanofibrous dressing loaded with Prussian blue and heparin for anti-inflammation therapy and diabetic wound healing

Diabetic ulcer is a severe complication of diabetes that can lead to amputation due to the overproduction of pro-inflammatory factors and reactive oxygen species (ROS). In this study, a composite nanofibrous dressing was developed by combining Prussian blue nanocrystals (PBNCs) and heparin sodium (Hep) through electrospinning, electrospraying, and chemical deposition. The nanofibrous dressing (PPBDH) was designed to take advantage of the excellent pro-inflammatory factor-adsorbing capability of Hep and the ROS-scavenging capabilities of PBNCs, resulting in synergistic treatment. It is worth noting that the nanozymes were firmly anchored to the fiber surfaces through slight polymer swelling caused by the solvent during electrospinning, thereby guaranteeing the preservation of the enzyme-like activity levels of PBNCs. The PPBDH dressing was found to be effective in reducing intracellular ROS levels, protecting cells from ROS-induced apoptosis, and capturing excessive pro-inflammatory factors, including chemoattractant protein-1 (MCP-1) and interleukin-1β (IL-1β). Furthermore, a chronic wound healing evaluation conducted in vivo demonstrated that the PPBDH dressing was able to effectively alleviate the inflammatory response and accelerate wound healing. This research presents an innovative approach to fabricate nanozyme hybrid nanofibrous dressings, which have great potential in accelerating the healing of chronic and refractory wounds with uncontrolled inflammation.

Pomegranate-inspired multifunctional nanocomposite wound dressing for intelligent self-monitoring and promoting diabetic wound healing

Diabetic wounds are chronically hard-healing wounds. Bacterial infection, persistent inflammation and impaired angiogenesis are key factors affecting diabetic wound healing. Herein, inspired by pomegranate, Au/Ag nanodots (Au/AgNDs) with fluorescent and photothermal properties were adopted as the pomegranate-like core, and the polyvinyl alcohol hydrogel as the pomegranate-like shell to obtain the multifunctional nanocomposite wound dressing for promoting diabetic wounds healing and real-time self-monitoring the dressing state. On the one hand, the antibacterial and photothermal therapy synergistic strategy based on the nanocomposite has an excellent treatment effect on diabetic wounds by highly antibacterial, anti-inflammation, accelerating collagen deposition and angiogenesis. On the other hand, the nanocomposite can be used as "smart messenger" to determine the appropriate time for dressing replacement. With the release of Au/AgNDs from the nanocomposite, the photothermal performance and antibacterial activity of the wound dressing were reduced, and the fluorescence intensity decreased. The change of fluorescence intensity can be visualized by the naked eye, which guides the appropriate time for dressing replacement, and avoids secondary wound damage caused by frequent and blind dressing replacement. This work provides an effective strategy for the treatment of diabetic wounds and intelligent self-monitoring of the state of dressings in clinical practice.

Yttrium Oxide Nanoparticle-Loaded, Self-Assembled Peptide Gel with Antibacterial, Anti-Inflammatory, and Proangiogenic Properties for Wound Healing

Chronic wounds are a major healthcare challenge owing to their complex healing mechanism and number of impediments to the healing process, like infections, unregulated inflammation, impaired cellular functions, poor angiogenesis, and enhanced protease activity. Current topical care strategies, such as surgical debridement, absorption of exudates, drug-loaded hydrogels for infection and inflammation management, and exogenous supply of growth factors for angiogenesis and cell proliferation, slow the progression of wounds and reduce patient suffering but suffer from low overall cure rates. Therefore, we have developed a proteolytically stable, multifunctional nanoparticle loaded-peptide gel with inherent anti-inflammatory, antibacterial, and pro-angiogenic properties to provide a favorable wound healing milieu by restoring impaired cellular functions. We have fabricated a self-assembled, lauric acid-peptide conjugate gel, LA-LLys-DPhe-LLys-NH2, loaded with yttrium oxide (Y2O3) nanoparticles (NLG). Gel formed a nanofibrous structure, and nanoparticles were passively entrapped within the network. The surface morphology, stability, viscoelastic, and self-healing characteristics of gels were characterized. It showed a high stability against degradation by proteolytic enzymes and highly potent antibacterial activities against E. coli and S. aureus due to the presence of positively charged side chains of lysine in the peptide chain. It also exhibited an excellent antioxidant activity as well as ability to stimulate cell proliferation in murine fibroblast (L929) cells and human umbilical vein endothelial cells (HUVECs). The incorporation of nanoparticles promoted angiogenesis by upregulating pro-angiogenic genes, vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF2), and epidermal growth factor (EGFR), and the gel caused complete wound closure in cells. In summary, the Y2O3 nanoparticle-loaded lauric acid-peptide conjugate gel is able to elicit the desired tissue regeneration responses and, therefore, has a strong potential as a matrix for the treatment of chronic wounds.

Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) Prepared by Microwave and Ultrasound-Assisted Synthesis: Promising Green Strategies for the Nanoworld

Many pharmaceutically active molecules are highly lipophilic, which renders their administration and adsorption in patients extremely challenging. Among the countless strategies to overcome this problem, synthetic nanocarriers have demonstrated superb efficiency as drug delivery systems, since encapsulation can effectively prevent a molecules' degradation, thus ensuring increased biodistribution. However, metallic and polymeric nanoparticles have been frequently associated with possible cytotoxic side effects. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), which are prepared with physiologically inert lipids, therefore emerged as an ideal strategy to bypass toxicities issues and avoid the use of organic solvents in their formulations. Different approaches to preparation, using only moderate amounts of external energy to facilitate a homogeneous formation, have been proposed. Greener synthesis strategies have the potential to provide faster reactions, more efficient nucleation, better particle size distribution, lower polydispersities, and furnish products with higher solubility. Particularly microwave-assisted synthesis (MAS) and ultrasound-assisted synthesis (UAS) have been utilized in the manufacturing of nanocarrier systems. This narrative review addresses the chemical aspects of those synthesis strategies and their positive influence on the characteristics of SLNs and NLCs. Furthermore, we discuss the limitations and future challenges for the manufacturing processes of both types of nanoparticles.

Engineering exosome-based biomimetic nanovehicles for wound healing

Complexity and difficulties in wound management are pressing concerns that affect patients' quality of life and may result in tissue infection, necrosis, and loss of local and systemic functions. Hence, novel approaches to accelerate wound healing are being actively explored over the last decade. Exosomes as important mediators of intercellular communications are promising natural nanocarriers due to their biocompatibility, low immunogenicity, drug loading and targeting capacities, and innate stability. More importantly, exosomes are developed as a versatile pharmaceutical engineering platform for wound repair. This review provides an overview of the biological and physiological functions of exosomes derived from a variety of biological origins during wound healing phases, strategies for exosomal engineering, and therapeutic applications in skin regeneration.

A hydrogel dressing with tunable critical temperature and photothermal modulating melittin release for multiply antibacterial treatment

It is imperative to develop an antibiotic-free and long-term effective strategy for treating chronic wound infections due to the long-term utilization of antibiotics easily causing drug resistance. Herein, we fabricated a novel poly-N-isopropylacrylamide (PNIPAM)/polyacrylamide (PAM) coupling thermosensitive hydrogel integrating 1D lysozyme nanofiber doped with CuS nanoparticles (CuS/PP) and loading antibacterial peptide melittin (M) (CuS/PP-M) for combating chronic wound infection via photothermal modulating the release of melittin. For the CuS/PP-M hydrogel, the copolymerization of PNIPAM and PAM allows the lower critical solution temperature (LCST) higher than the body temperature, effectively hindering the spontaneous release of melittin when contacts the infected wound, while the integration of LNF/CuS nanofibers provides a stable photothermal treatment for triggering the release of melittin. As a result, the CuS/PP-M hydrogel exhibits synergistically enhanced effect on killing both Gram-positive and Gram-negative bacteria, which maintains more than 99 % bactericidal efficiency, even displays a long-term and multiply antibacterial performance by photothermal modulating melittin release. Moreover, the CuS/PP-M hydrogel presents both high antibacterial activity and excellent wound healing performance in the mouse wound model, thereby benefiting the chronic wound healing.

Combinational System of Lipid-Based Nanocarriers and Biodegradable Polymers for Wound Healing: An Updated Review

Skin wounds have imposed serious socioeconomic burdens on healthcare providers and patients. There are just more than 25,000 burn injury-related deaths reported each year. Conventional treatments do not often allow the re-establishment of the function of affected regions and structures, resulting in dehydration and wound infections. Many nanocarriers, such as lipid-based systems or biobased and biodegradable polymers and their associated platforms, are favorable in wound healing due to their ability to promote cell adhesion and migration, thus improving wound healing and reducing scarring. Hence, many researchers have focused on developing new wound dressings based on such compounds with desirable effects. However, when applied in wound healing, some problems occur, such as the high cost of public health, novel treatments emphasizing reduced healthcare costs, and increasing quality of treatment outcomes. The integrated hybrid systems of lipid-based nanocarriers (LNCs) and polymer-based systems can be promising as the solution for the above problems in the wound healing process. Furthermore, novel drug delivery systems showed more effective release of therapeutic agents, suitable mimicking of the physiological environment, and improvement in the function of the single system. This review highlights recent advances in lipid-based systems and the role of lipid-based carriers and biodegradable polymers in wound healing.

Bioengineered Water-Responsive Carboxymethyl Cellulose/Poly(vinyl alcohol) Hydrogel Hybrids for Wound Dressing and Skin Tissue Engineering Applications

The burden of chronic wounds is growing due to the increasing incidence of trauma, aging, and diabetes, resulting in therapeutic problems and increased medical costs. Thus, this study reports the synthesis and comprehensive characterization of water-responsive hybrid hydrogels based on carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) using citric acid (CA) as the chemical crosslinking agent, with tunable physicochemical properties suitable to be applied as a wound dressing for soft tissue engineering applications. They were produced through an eco-friendly process under mild conditions. The hydrogels were designed and produced with flexible swelling degree properties through the selection of CMC molecular mass (Mw = 250 and 700 kDa) and degree of functionalization (DS = 0.81), degree of hydrolysis of PVA (DH > 99%, Mw = 84-150 kDa) associated with synthesis parameters, CMC/PVA ratio and extension of chemical crosslinking (CA/CMC:PVA ratio), for building engineered hybrid networks. The results demonstrated that highly absorbent hydrogels were produced with swelling degrees ranging from 100% to 5000%, and gel fraction from 40% to 80%, which significantly depended on the concentration of CA crosslinker and the presence of PVA as the CMC-based network modifier. The characterizations indicated that the crosslinking mechanism was mostly associated with the chemical reaction of CA carboxylic groups with hydroxyl groups of CMC and PVA polymers forming ester bonds, rendering a hybrid polymeric network. These hybrid hydrogels also presented hydrophilicity, permeability, and structural features dependent on the degree of crosslinking and composition. The hydrogels were cytocompatible with in vitro cell viability responses of over 90% towards model cell lines. Hence, it is envisioned that this research provides a simple strategy for producing biocompatible hydrogels with tailored properties as wound dressings for assisting chronic wound healing and skin tissue engineering applications.

Fibroblast-targeting polymeric nanovehicles to enhance topical wound healing through promotion of PAR-2 receptor-mediated endocytosis

The level of collagen production critically determines skin wound contraction. If an intelligent skin drug delivery technology that enables collagen production in a specific wound skin area is developed, a breakthrough in wound healing treatment would be expected. However, such an intelligent drug delivery technology has not yet been developed as much as in the field of anticancer therapy. In this study, we propose a smart drug delivery system using polymeric nanovehicles (PNVs), in which the periphery is conjugated with a fibroblast-targeting collagen-derived peptide, KTTKS (Lys-Thr-Thr-Lys-Ser). We showed that surface engineering of PNVs with simultaneous PEGylation and peptide patching improved the dispersibility of PNVs, while promoting selective cellular uptake to fibroblasts via PAR-2 receptor-mediated endocytosis. In vitro collagen production and in vivo wound healing assays revealed that curcumin-loaded fibroblast-targeting PNVs significantly enhanced collagen production and wound healing activities, thus promising effective skin tissue regeneration.

Wound Healing Properties of Natural Products: Mechanisms of Action

A wound is the loss of the normal integrity, structure, and functions of the skin due to a physical, chemical, or mechanical agent. Wound repair consists of an orderly and complex process divided into four phases: coagulation, inflammation, proliferation, and remodeling. The potential of natural products in the treatment of wounds has been reported in numerous studies, emphasizing those with antioxidant, anti-inflammatory, and antimicrobial properties, e.g., alkaloids, saponins, terpenes, essential oils, and polyphenols from different plant sources, since these compounds can interact in the various stages of the wound healing process. This review addresses the most current in vitro and in vivo studies on the wound healing potential of natural products, as well as the main mechanisms involved in this activity. We observed sufficient evidence of the activity of these compounds in the treatment of wounds; however, we also found that there is no consensus on the effective concentrations in which the natural products exert this activity. For this reason, it is important to work on establishing optimal treatment doses, as well as an appropriate route of administration. In addition, more research should be carried out to discover the possible side effects and the behavior of natural products in clinical trials.

A Comprehensive Review on Bio-Based Materials for Chronic Diabetic Wounds

Globally, millions of people suffer from poor wound healing, which is associated with higher mortality rates and higher healthcare costs. There are several factors that can complicate the healing process of wounds, including inadequate conditions for cell migration, proliferation, and angiogenesis, microbial infections, and prolonged inflammatory responses. Current therapeutic methods have not yet been able to resolve several primary problems; therefore, their effectiveness is limited. As a result of their remarkable properties, bio-based materials have been demonstrated to have a significant impact on wound healing in recent years. In the wound microenvironment, bio-based materials can stimulate numerous cellular and molecular processes that may enhance healing by inhibiting the growth of pathogens, preventing inflammation, and stimulating angiogenesis, potentially converting a non-healing environment to an appropriately healing one. The aim of this present review article is to provide an overview of the mechanisms underlying wound healing and its pathophysiology. The development of bio-based nanomaterials for chronic diabetic wounds as well as novel methodologies for stimulating wound healing mechanisms are also discussed.

Electrospun Mucoadhesive Zein/PVP Fibroporous Membrane for Transepithelial Delivery of Propranolol Hydrochloride

Mucoadhesive drug delivery systems have been extensively studied to effectively reduce the limitations of conventional drug delivery systems. Zein and polyvinyl pyrrolidone (PVP) are appraised for mucoadhesive properties. This study focuses on developing a mechanically stable zein/PVP electrospun membrane for propranolol hydrochloride (PL) transport. Fourier transform infrared, Raman spectra, and swelling studies gave evidence for PVP crosslinking, whereas circular dichroism spectroscopy revealed crosslinking of zein owing to the conformational change from α-helix to β-sheet. A 10 h thermal treatment of zein/PVP imparted 3.92 ± 0.13 MPa tensile strength to the matrix. Thermally crosslinked electrospun zein/PVP matrix showed 22.1 ± 0.1 g mm work of adhesion in porcine buccal mucosa tissue. Qualitative and quantitative evaluation of cytotoxicity in RPMI 2650 has been carried out. The in vitro drug release profile of PL from thermally crosslinked zein/PVP best fitted with the Korsmeyer-Peppas model. Immunostaining of β-catenin adherens junctional protein confirmed the absence of paracellular transport through the junctional opening. Still, drug permeation was observed through the porcine buccal mucosa, attributed to the transcellular transport of PL owing to its lipophilicity. The ex vivo permeation of PL through porcine buccal mucosa was also evaluated.

Global trends in research of high-throughput sequencing technology associated with chronic wounds from 2002 to 2022: A bibliometric and visualized study

Background

Chronic wounds are a complex medical problem. With the difficulty of skin healing, the microbial ecology of chronic wounds is an essential factor affecting wound healing. High-throughput sequencing (HTS) technology is a vital method to reveal the microbiome diversity and population structure of chronic wounds.

Objective

The aim of this paper was to delineate the scientific output characteristics, research trends, hotspots and frontiers of HTS technologies related to chronic wounds globally over the past 20 years.

Methods

We searched the Web of Science Core Collection (WoSCC) database for articles published between 2002 and 2022 and their full record information. The Bibliometrix software package was used to analyze bibliometric indicators and VOSviewer visualization analysis results.

Results

Ultimately, a total of 449 original articles were reviewed, and the results showed that the number of annual publications (Nps) about HTS associated with chronic wounds has steadily increased over the last 20 years. The United States and China produce the most articles and have the highest H-index, while the United States and England have the largest number of citations (Nc) in this field. The University of California, Wound Repair and Regeneration and National Institutes of Health Nih United States were the most published institutions, journals and fund resources, respectively. The global research could be divided into 3 clusters as follows: microbial infection of chronic wounds, the healing process of wounds and microscopic processes, skin repair mechanism stimulated by antimicrobial peptides and oxidative stress. In recent years, "wound healing", "infections", "expression", "inflammation", "chronic wounds", "identification" and "bacteria" "angiogenesis", "biofilms" and "diabetes" were the most frequently used keywords. In addition, research on "prevalence", "gene expression", "inflammation" and "infection" has recently become a hotspot.

Conclusions

This paper compares the research hotspots and directions in this field globally from the perspectives of countries, institutions and authors, analyzes the trend of international cooperation, and reveals the future development direction of the field and research hotspots of great scientific research value. Through this paper, we can further explore the value of HTS technology in chronic wounds to better solve the problem of chronic wounds.

Microenvironment-Based Diabetic Foot Ulcer Nanomedicine

Diabetic foot ulcers (DFU), one of the most serious complications of diabetes, are essentially chronic, nonhealing wounds caused by diabetic neuropathy, vascular disease, and bacterial infection. Given its pathogenesis, the DFU microenvironment is rather complicated and characterized by hyperglycemia, ischemia, hypoxia, hyperinflammation, and persistent infection. However, the current clinical therapies for DFU are dissatisfactory, which drives researchers to turn attention to advanced nanotechnology to address DFU therapeutic bottlenecks. In the last decade, a large number of multifunctional nanosystems based on the microenvironment of DFU have been developed with positive effects in DFU therapy, forming a novel concept of "DFU nanomedicine". However, a systematic overview of DFU nanomedicine is still unavailable in the literature. This review summarizes the microenvironmental characteristics of DFU, presents the main progress of wound healing, and summaries the state-of-the-art therapeutic strategies for DFU. Furthermore, the main challenges and future perspectives in this field are discussed and prospected, aiming to fuel and foster the development of DFU nanomedicines successfully.

Current Progress and Outlook of Nano-Based Hydrogel Dressings for Wound Healing

Wound dressing is an important tool for wound management. Designing wound dressings by combining various novel materials and drugs to optimize the peri-wound environment and promote wound healing is a novel concept. Hydrogels feature good ductility, high water content, and favorable oxygen transport, which makes them become some of the most promising materials for wound dressings. In addition, nanomaterials exhibit superior biodegradability, biocompatibility, and colloidal stability in wound healing and can play a role in promoting healing through their nanoscale properties or as carriers of other drugs. By combining the advantages of both technologies, several outstanding and efficient wound dressings have been developed. In this paper, we classify nano-based hydrogel dressings into four categories: hydrogel dressings loaded with a nanoantibacterial drug; hydrogel dressings loaded with oxygen-delivering nanomedicines; hydrogel dressings loaded with nanonucleic acid drugs; and hydrogel dressings loaded with other nanodelivered drugs. The design ideas, advantages, and challenges of these nano-based hydrogel wound dressings are reviewed and analyzed. Finally, we envisaged possible future directions for wound dressings in the context of relevant scientific and technological advances, which we hope will inform further research in wound management.

Catechol-chitosan/polyacrylamide hydrogel wound dressing for regulating local inflammation

Chronic wounds and the accompanying inflammation are ongoing challenges in clinical treatment. They are usually accompanied by low pH and high oxidative stress environments, limiting cell growth and proliferation. Ordinary medical gauze has limited therapeutic effects on chronic wounds, and there is active research to develop new wound dressings. The chitosan hydrogel could be widely used in biomedical science with great biocompatibility, but the low mechanical properties limit its development. This work uses polyacrylamide to prepare double-network (DN) hydrogels based on bioadhesive catechol-chitosan hydrogels. Cystamine and N, N′-Bis(acryloyl)cystamine, which can be cross-linking agents with disulfide bonds to prepare redox-responsive DN hydrogels and pH-responsive nanoparticles (NPs) prepared by acetalized cyclodextrin (ACD) are used to intelligently release drugs against chronic inflammation microenvironments. The addition of catechol groups and ACD-NPs loaded with the Resolvin E1 (RvE1), promotes cell adhesion and regulates the inflammatory response at the wound site. The preparation of the DN hydrogel in this study can be used to treat and regulate the inflammatory microenvironment of chronic wounds accurately. It provides new ideas for using inflammation resolving factor loaded in DN hydrogel of good biocompatibility with enhanced mechanical properties to intelligent regulate the wound inflammation and promote the wound repaired.

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Dual-response hydrogel drug delivery system was used to intelligently release drugs at inflammation area of chronic wound.

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DN hydrogel was designed to enhance the properties of chitosan-based hydrogel with two cross-linking agents.

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Resolvin E1 loaded into wound dressing can help to regulate wound inflammation by regulating macrophage behavior.

Advances in microRNA from adipose-derived mesenchymal stem cell-derived exosome: focusing on wound healing

Skin wounds are a common condition causing economic burden and they represent an urgent clinical need, especially chronic wounds. Numerous studies have been conducted on the applications of stem cell therapy in wound healing, with adipose-derived mesenchymal stem cells (ADMSCs) playing a major role since they can be isolated easily, yielding a high number of cells, the less invasive harvesting required, the longer life span and no ethical issues. However, the lack of standardized doses and protocols, the heterogeneity of clinical trials, as well as the incompatibility of the immune system limit its application. Recent studies have demonstrated that specific stem cell functions depend on paracrine factors, including extracellular vesicles, in which microRNAs in exosomes (Exo-miRNAs) are essential in controlling their functions. This paper describes the application and mechanism whereby ADMSC-Exo-miRNA regulates wound healing. ADMSC-Exo-miRNA is involved in various stages in wounds, including modulating the immune response and inflammation, accelerating skin cell proliferation and epithelialization, promoting vascular repair, and regulating collagen remodeling thereby reducing scar formation. In summary, this acellular therapy based on ADMSC-Exo-miRNA has considerable clinical potential, and provides reference values for developing new treatment strategies for wound healing.

Chondroitin sulfate-based composites: a tour d'horizon of their biomedical applications

Chondroitin sulfate (CS), a natural anionic mucopolysaccharide, belonging to the glycosaminoglycan family, acts as the primary element of the extracellular matrix (ECM) of diverse organisms. It comprises repeating units of disaccharides possessing β-1,3-linked N-acetyl galactosamine (GalNAc), and β-1,4-linked D-glucuronic acid (GlcA), and exhibits antitumor, anti-inflammatory, anti-coagulant, anti-oxidant, and anti-thrombogenic activities. It is a naturally acquired bio-macromolecule with beneficial properties, such as biocompatibility, biodegradability, and immensely low toxicity, making it the center of attention in developing biomaterials for various biomedical applications. The authors have discussed the structure, unique properties, and extraction source of CS in the initial section of this review. Further, the current investigations on applications of CS-based composites in various biomedical fields, focusing on delivering active pharmaceutical compounds, tissue engineering, and wound healing, are discussed critically. In addition, the manuscript throws light on preclinical and clinical studies associated with CS composites. A short section on Chondroitinase ABC has also been canvassed. Finally, this review emphasizes the current challenges and prospects of CS in various biomedical fields.

Microcurrent and Gold Nanoparticles Combined with Hyaluronic Acid Accelerates Wound Healing

This study aimed to investigate the effects of iontophoresis and hyaluronic acid (HA) combined with a gold nanoparticle (GNP) solution in an excisional wound model. Fifty Wistar rats (n = 10/group) were randomly assigned to the following groups: excisional wound (EW); EW + MC; EW + MC + HA; EW + MC + GNPs; and EW + MC + HA + GNPs. The animals were induced to a circular excision, and treatment started 24 h after injury with microcurrents (300 µA) containing gel with HA (0.9%) and/or GNPs (30 mg/L) in the electrodes (1 mL) for 7 days. The animals were euthanized 12 h after the last treatment application. The results demonstrate a reduction in the levels of pro-inflammatory cytokines (IFNϒ, IL-1β, TNFα, and IL-6) in the group in which the therapies were combined, and they show increased levels of anti-inflammatory cytokines (IL-4 and IL-10) and growth factors (FGF and TGF-β) in the EW + MC + HA and EW + MC + HA + GNPs groups. As for the levels of dichlorofluorescein (DCF) and nitrite, as well as oxidative damage (carbonyl and sulfhydryl), they decreased in the combined therapy group when compared to the control group. Regarding antioxidant defense, there was an increase in glutathione (GSH) and a decrease in superoxide dismutase (SOD) in the combined therapy group. A histological analysis showed reduced inflammatory infiltrate in the MC-treated groups and in the combination therapy group. There was an increase in the wound contraction rate in all treated groups when compared to the control group, proving that the proposed therapies are effective in the epithelial healing process. The results of this study demonstrate that the therapies in combination favor the tissue repair process more significantly than the therapies in isolation.