Wound healing applications of creams and "smart" hydrogels

Layer-by-layer assembly: advancing skin repair, one layer at a time

Skin wound management remains a critical global healthcare challenge, with annual costs exceeding £30 billion. Traditional treatments like autografts face limitations in cost, availability, and recovery times. This review explores spray-assisted Layer-by-Layer (LbL) technology as a transformative approach for wound healing, emphasising its ability to deposit natural- and synthetic-polyelectrolytes such as chitosan, alginate, hyaluronic acid, and collagen into nanoscale coatings. These biocompatible multilayers integrate therapeutic agents to accelerate healing, reduce infections, and mimic native extracellular matrix structures. The work highlights emerging spray device innovations that optimise spray parameters to enhance cell viability, coverage, and clinical outcomes. While LbL techniques demonstrate versatility across substrates and scalability via immersion, spray, and microfluidic methods, challenges persist in manufacturing uniformity and clinical translation. The review underscores the urgent need for clinical trials to validate Lbl-based coatings in real-world settings and addresses gaps in portable, sustainable device development. By bridging advanced materials science with clinical practice, spray-assisted LbL technology offers a roadmap to overcome current wound care limitations, prioritising biocompatibility, cost-efficiency, and improved patient safety in regenerative medicine.

Skin and Wound Healing: Conventional Dosage versus Nanobased Emulsions Forms

The skin plays a crucial role in the body's homeostasis through its thermoregulation functions, metabolic activity, and, mainly, its barrier function. Once this system has its homeostasis disturbed, through the promotion of tissue discontinuity, an injury happens and a restoration process starts. Different products can be used to promote, accelerate, or stimulate the healing process, such as hydrogels, emulsions, and ointments (main conventional formulations). Despite the historical use and wide market and consumer acceptance, new systems emerged for wound management with the main challenge to overcome conventional form limitations, in which nanosystems are found, mainly nanobased emulsion forms (nano- and microemulsions, NE and ME). Here, we discuss the skin function and wound healing process, highlighting the cellular and molecular processes, the different wound classifications, and factors that affect physiological healing. We also investigated the recent patents (2012-2023) filed at the United States Patent and Trademark Office, where we found few patents for conventional forms (hydrogels = 5; emulsions = 4; ointments = 6) but a larger number of patents for nanobased emulsions filed in this time (NE = 638; ME = 4,072). Furthermore, we address the use of nanobased emulsions (NE and ME) and their particularities, differences, and application in wound treatment. This work also discusses the challenges, bottlenecks, and regulatory framework for nanosystems, industrial, academic, and government interest in nanotechnology, and future perspectives about this key factor for the nanosystems market and consumer acceptance.

In vitro, ex vivo, and in vivo studies of celecoxib topical platforms for antimicrobial activity and wound healing: a comparative assessment

BACKGROUND & RATIONALE

Celecoxib (CXB), with its anti-inflammatory and recently discovered antibacterial activity, especially against sensitive and methicillin-resistant Staphylococcus aureus (MRSA), could be promising in treating local pain, superficial skin infections, wounds and infected wounds. The study aims to develop and compare commercially scalable topical formulations of CXB to explore their antimicrobial and wound-healing potential.

METHODS

Carbopol gel, o/w cream, polyethylene glycol (PEG) ointment, and paraffin ointment were selected as the vehicles for the preparation of 3% CXB topical formulations. Appearance, pH, viscosity, spreadability, drug content, stability, in vitro release and permeation, and skin retention studies were performed. Further, antimicrobial assay, in vivo wound-healing and histopathology studies were carried out for each formulation.

RESULTS

The formulations had an acceptable appearance, viscosity, spreadability, and drug content. The drug release at 6h was the highest from gel (2428.8ug/cm2), followed by PEG ointment (2230.1ug/cm2), cream (1897.8ug/cm2), and lastly, the paraffin ointment (1217.2ug/cm2). PEG ointment and gel showed the highest skin permeation, whereas cream and gel were better able to retain the drug in the skin. All the formulations exhibited appreciable zones of inhibition against sensitive and the resistant strains of Staphylococcus aureus. PEG ointment exerted a significantly greater (p < 0.001) wound-healing effect. Accelerated stability studies confirmed good physicochemical stability of the formulations.

CONCLUSION

PEG ointment, with its optimal drug release profile, skin permeation ability, and greater wound-healing action, can be considered as a promising topical delivery vehicle for CXB. CXB's antimicrobial potential could further aid in the prevention as well as treatment of wound infection.

Green synthesized (Curcuma longa) Ni nanoparticles doped chitosan and PEG for wound healing and anti-bacterial activity

The development of advanced wound dressings with enhanced absorption capacity and reduced adhesion is critical for effective wound management. This study presents a novel approach utilizing nickel (Ni) nanoparticles synthesized using curcumin extracted from Curcuma longa, known for its wound healing and antimicrobial properties. The Ni nanoparticles were incorporated with chitosan and polyethylene glycol (PEG) to form cross-linked nanocomposites with improved absorptive and mechanical properties. The wound healing potential was assessed through histopathological analysis, wound contraction rates, and antibacterial activity against Escherichia coli. The results demonstrated accelerated wound closure within 10-12 days, enhanced tissue regeneration, and significant antibacterial efficacy. Structural and compositional analyses, including UV-Visible spectroscopy, FTIR, XRD, Zeta Potential, EDX, and SEM, confirmed the successful synthesis and stability of the nanocomposites. This study highlights the potential of curcumin-loaded nanocomposites (CS-Ni and PEGNi) as a promising wound dressing material, paving the way for nanotechnology-driven innovations in wound care and tissue engineering.

Using Three-Dimensional Bioprinting to Generate Realistic Models of Wound Healing

Significance: The skin serves as the primary defense against external stimuli, making it vulnerable to damage. Injuries can cause a dysregulated environment, resulting in chronic inflammation and inhibition of cell proliferation and migration, which delays recovery. Innovative approaches, such as three-dimensional (3D) bioprinting, can foster a controlled healing environment by promoting synergy between the skin microbiome and cells. Recent Advances: Traditional approaches to wound healing have focused on fostering an environment conducive to the interplay between cells, extracellular proteins, and growth factors. 3D bioprinting, a manufacturing technology with applications in tissue engineering, deposits biomaterial-based bioink containing living cells to fabricate custom-designed tissue scaffolds in a layer-by-layer fashion. This process controls the architecture and composition of a construct, producing multilayered and complex structures such as skin. Critical Issues: The selection of biomaterials for scaffolds has been a challenge when 3D skin tissue engineering. While prioritizing mechanical properties, current biomaterials often lack the ability to interact with environmental stimuli such as pH, temperature, or oxygen levels. Employing smart biomaterials that integrate bioactive molecules and adapt to external conditions could overcome these limitations. This innovation would enable scaffolds to create a sustainable wound-healing environment, fostering microbiome balance, reducing inflammation, and facilitating cellular recovery and tissue restoration, addressing critical gaps in existing wound care solutions. Future Directions: Novel bioink formulations for skin injury recovery are focused on improving long-term cell viability, proliferation, vascularization, and immune integration. Efficient recovery of the skin microbiome using bioactive molecules has the potential to create microenriched environments that support the recovery of the skin microbiome and restore immune regulation. This promising direction for future research aims to improve patient outcomes in wound care.

Bioengineering strategies for regeneration of skin integrity: A literature review

Objective

The skin is a complex organ that includes various stem cell populations. Current approaches for non-healing skin defects are sometimes inadequate and many attempts have been made to regenerate skin integrity. The aim of this review is to bridge the gap between basic research and clinical application of skin integrity regeneration.

Methods

A literature search was carried out in PubMed using combinations of the keywords "skin integrity", "tissue-engineered skin", "bioengineered skin", and "skin regeneration". Articles published from 1968 to 2023 reporting evidence from in vivo and in vitro skin regeneration experiments were included.

Results

These articles showed that stem cells can be differentiated into normal skin cells, including keratinocytes, and are a significant source of skin organoids, which are useful for investigating skin biology; and that emerging direct reprogramming methods have great potential to regenerate skin from the wounded skin surface.

Conclusion

Recent advances in skin regeneration will facilitate further advancement of both basic and clinical research in skin biology.

Pseudo-ternary phase diagram based PEGylated nano-dispersion of linezolid to promote wound regeneration: an in vitro and in vivo evaluation

Open wounds are prone to bacterial infiltration mostly resistant strains like methicillin-resistant Staphylococcus aureus (MRSA), which affects healing of open wounds. Topical linezolid nano-dispersion using essential oils as nanoemulgel can increase solubility of drug and bypass side-effects like GI-irritation of oral administration. Pseudo-ternary phase diagram was built to optimise nanoemulsion. Surfactant/co-surfactant mixture (3:1), deionised water and Oilmix (4:1) with drug were vortexed and then ultrasonicated. 1% carbopol gel of optimised nanoemulsion was prepared and characterised, exposed to antimicrobial study, cytocompatibility study using HEK293 cell-line, and in vivo wound healing study using rat excision model. Histological study was performed to confirm growth of stratum corneum. Optimised formulation has particle size (244.6 ± 178.66 nm), polydispersity index (25%), entrapment efficiency (92.3 ± 3.38%) and in vitro drug release (87.58 ± 4.16%) best fitted in Korsmeyer-Peppas kinetics model. Nanoemulgel F6 (0.2%w/w) was found with viscosity of 5345 ± 6 cP constituting a very excellent antimicrobial effect against MRSA. HEK293 cells had shown good cytocompatibility with formulation. The wound contraction rate was 99.66 ± 0.57% at day 15 on daily application of nanoemulgel and stratum corneum was almost fully regenerated. The developed nanoemulgel has potential antimicrobial efficacy and can promote wound healing.

Recent advances in the use of essential oils and their nanoformulations for wound treatment

Despite progress in medical and surgical treatments of wounds, bioactive compounds still offer an effective and safe approach to accelerate wound healing (WH). In this review, recent results of studies on WH by essential oils (EOs) and their terpenoids are reported. Mechanisms of action of these substances and their possible use in drug delivery systems (DDSs) for WH are discussed. EOs of 38 species from 16 families have been evaluated for their potential to treat wounds. Lamiaceae was the most representative family with 10 species, followed by Myrtaceae and Asteraceae. EOs improve WH by acting as anti-inflammatory, antioxidant, and antimicrobial agents. Some other EOs were involved by increasing expression of transforming growth factor (TGF), inhibition of several factors, including plasminogen activator inhibitor-1 (PAI-1), substitution of type III collagen by type I collagen, and up-regulation of insulin-like growth factor-1 (IGF-1), fibroblast growth factor 2 (FGF-2), and vascular endothelial growth factor (VEGF). These mechanisms improved repair of cells and increased proliferation. Alternatively, DDSs based on nanomaterials (NMs) used to carry EOs for WH are mainly based on nanoparticles (NPs), microparticles (MPs) and scaffolds. There is much evidence that EOs can promote WH. Advancement of nanotechnology in recent years has contributed to improving use of EO with DDSs in WH management. However, some limitations need to be addressed to achieve the translation of this technology into clinical applications for wound treatment.

Systematic Review on the Efficacy of Moisturizing Therapy in Treating Nipple Trauma and Nipple Pain

BACKGROUND

Nipple trauma and pain pose a challenge, leading to premature discontinuation of breastfeeding. Moisturizing therapies, including lanolin and hydrogel dressings, have been proposed for nipple trauma and pain management. Despite the availability of multiple approaches, evidence for moisturizing therapy is lacking.

RESEARCH AIM

This review aimed to determine the efficacy of moisturizing therapy in treating nipple trauma and nipple pain in lactating women.

METHODS

A systematic review based on the PRISMA-P guidelines was conducted. Seven databases were systematically searched and screened, and 24 studies were analyzed. The interventions were categorized as high, moderate, or low, based on their moisturization levels. Sample characteristics, interventions, and outcomes were examined.

RESULTS

A total of 21 interventions were identified: high moisturization (two types), moderate moisturization (12 types), and low moisturization (seven types). Hydrogel dressings, lanolin, and breast milk are commonly used interventions. Although intervention and effectiveness evaluation methods differed between studies and could not be compared, results in 10 (41%) of the studies demonstrated that one intervention with more moistening was more effective. Of the three studies categorized as including high moistening interventions, two (66%) supported their effectiveness compared to low moistening interventions; however, two of the three studies were judged to be at high risk of bias, and some reported adverse events.

CONCLUSIONS

Moisturization interventions show promise for treating nipple trauma and pain more than drying nipples or using breast milk, but high moisturization needs cautious use due to few rigorous trials and the presence of reported risks. Methodological challenges and the lack of robust trials hinder evidence synthesis and robust conclusions.

ABSTRACT IN JAPANESE

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Formulation development of highly stable collagenase-containing hydrogels for wound healing

Collagenases are enzymes that break down collagen and are used in wound healing and treating various disorders. Currently, collagenase is commercially available in only ointment and injectable forms and is sensitive to various environmental factors. In the present study, different hydrogel formulations of collagenase have been prepared at pH 6.5 using carboxymethylcellulose sodium and zinc acetate with and without humectants such as propylene glycol (PG) and glycerin (GL) in varying concentrations. The formulated gels were stored at room temperature (25±2°C, 60±5% RH) and refrigerator temperature (5±3°C) for six months to evaluate their physical and up to six years for chemical stability. The gels were subjected to various tests, including organoleptic studies, spreadability, moisture content, swelling index, swelling/de-swelling, syneresis, viscosity, gelation time, and weight variation. The purity and molecular weight of collagenase have been determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). At the same time, its activity during the storage period was evaluated by gelatin zymography. Casein zymography was also performed to detect any caseinase contamination in the formulations. The release of the enzyme from different gel formulations was assessed using the Franz diffusion apparatus and analyzed by gelatin zymography. The results showed some physical changes that were more prominent in gels stored at room temperature than those kept refrigerated. The difference in humectant concentration was also found to affect the stability of gels. PG was found to be a better humectant than GL, particularly in a concentration of 25%. The zymography results indicated that collagenase was stable in all formulations kept in the refrigerator. In contrast, its complete degradation was noted in the preparations stored at room temperature within a month. The data generated in this study will help the formulators to commercialize a relatively economical gel formulation of collagenase that is highly stable for up to six years at refrigerator temperature (5±3°C).

Plant Extracellular Nanovesicle-Loaded Hydrogel for Topical Antibacterial Wound Healing In Vivo

Bacterial infections impede wound healing and pose significant challenges in clinical care. There is an immediate need for safe and targeted antivirulence agents to fight bacterial infections effectively. In this regard, bioderived nanovesicles have shown significant promise. This work demonstrated significant antibacterial properties of extracellular nanovesicles derived from plant (mint) leaf juice (MENV). A hydrogel (HG) was developed using oxidized alginate and chitosan and loaded with antibacterial MENVs (MENV-HG). This formulation was investigated for topical HG dressings to treat Gram-positive Micrococcus luteus and Gram-negative Escherichia coli-invasive wounds. The developed HG was injectable, biocompatible (>95% cell was viable), nonhemolytic (<5% hemolytic capacity), self-healing and exhibited strong physical and mechanical interactions with the bacteria cells (MENV-HG-treated bacteria were significantly more elastic compared to the control in both M. luteus (1.01 ± 0.3 MPa, p < 0.005 vs 5.03 ± 2.6) and E. coli (5.81 ± 2.1 MPa vs 10.81 ± 3.8, p < 0.005). MENV-HG was topically applied on wounds with a slow MENV release profile, ensuring effective healing. These in vivo results demonstrated decreased inflammation and expedited healing within 10 days of treatment (wound area closure was 99% with MENV-HG treatment and 87% for control). Taken together, MENV-HGs have the potential for a scalable and sustainable wound dressing strategy that works satisfactorily for bacteria-infected wound healing and to be validated in clinical trials.

Encapsulation of Hydrogen Peroxide in PVA/PVP Hydrogels for Medical Applications

Researchers have been investigating the physical and morphological properties of biodegradable polymer and copolymer films, blending them with other chemicals to solve challenges in medical, industrial, and eco-environmental fields. The present study introduces a novel, straightforward method for preparing biodegradable hydrogels based on polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) for medical applications. The resulting PVA/PVP-based hydrogel uniquely combines the water absorbency, biocompatibility, and biodegradability of the polymer composite. For hygiene products and medical uses, such as wound healing, hydrogen peroxide (HP) was encapsulated in the PVA/PVP hydrogels for controlled release application. Incorporating PVP into PVA significantly enhances the hydrogel water absorbency and improves the mechanical properties. However, to mitigate the disadvantage of high water absorbency which could result in undesired early dissolution, efforts were made to increase the water resistance and the mechanical characteristics of these hydrogels using freeze-thaw (F/T) cycles and chemical crosslinking PVA chains with trisodium trimetaphosphate (STMP). The resulting hydrogels serve as environmentally friendly bio-based polymer blends, broadening their applications in medical and industrial products. The structural and morphological properties of the hydrogel were characterized using Fourier transform infrared spectroscopy (FTIR), environmental scanning electron microscope analysis (E-SEM), and water-swelling tests. The HP controlled release rate was evaluated through kinetic release experiments using the ex vivo skin model. The antibacterial activity of the hydrogel films was examined on four medically relevant bacteria: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa, with an adapted disk diffusion assay. Using this assay, we also evaluated the antibacterial effect of the hydrogel films over the course of days, demonstrating the HP controlled release from these hydrogels. These findings support further in vivo investigation into controlled HP release systems for improved wound-healing outcomes.

An injectable hydrogel of porcine cholecyst extracellular matrix for accelerated wound healing

Hydrogel formulations of xenogeneic extracellular matrices have been widely used for topical wound care because of their exceptional tunability over other formulations like lyophilized sheets, powders, non-injectable gels, pastes, and ointments. This is important in the treatment of wounds with irregular shapes and depth. This study identified an injectable hydrogel formulation of porcine cholecyst extracellular matrix (60%) in medical-grade carboxymethyl cellulose (40%) as vehicle and evaluated its biomaterial properties. Further, an in-depth evaluation of in vivo wound healing efficacy was conducted in a rat full-thickness skin excision wound healing model, which revealed that the hydrogel formulation accelerated wound healing process compared to wounds treated with a commercial formulation and untreated wounds. The hydrogel appeared to have promoted a desirable pro-regenerative tissue reaction predominated by Th2 helper lymphocytes and M2 macrophages as well as an effective collagen remodeling indicative of diminished scarring. In conclusion, the porcine cholecyst extracellular matrix injectable hydrogel formulation appeared to be a promising candidate formulation as an advanced wound care biomaterial for faster healing of skin wounds with minimal scarring.

Involvement of macromolecules in 3D printing for wound healing management: A narrative review

Wound healing comprises four overlapping stages involving complex biochemical and cellular processes. Any lapse in this procedure causes irregular healing, which generates clinical and financial burdens for the health system. Personalized treatment is preferred to overcome the limitations of classical as well as modern methods of wound healing. This review discusses recently developed 3D printing models for personalized treatment with varying degrees of success. It is an effective approach for treating wounds by developing custom dressings tailored to the patient's needs and reducing incidents of infections. Additionally, incorporating natural or synthetic polymers can further enhance their effectiveness. Macromolecular polymers, laminin, cellulose, collagen, gelatin, etc. that make up the bulk of 3D printable bio-inks, have been essential in diverse 3D bioprinting technologies throughout the layered 3D manufacturing processes. The polymers need to be tailored for the specific requirements of printing and effector functions in cancer treatment, dental & oral care, biosensors, and muscle repair. We have explored how 3D printing can be utilized to fasten the process of wound healing at each of the four stages. The benefits as well as the future prospects are also discussed in this article.

Hydrogels for Nucleic Acid Drugs Delivery

Nucleic acid drugs are one of the hot spots in the field of biomedicine in recent years, and play a crucial role in the treatment of many diseases. However, its low stability and difficulty in target drug delivery are the bottlenecks restricting its application. Hydrogels are proven to be promising for improving the stability of nucleic acid drugs, reducing the adverse effects of rapid degradation, sudden release, and unnecessary diffusion of nucleic acid drugs. In this review, the strategies of loading nucleic acid drugs in hydrogels are summarized for various biomedical research, and classify the mechanism principles of these strategies, including electrostatic binding, hydrogen bond based binding, hydrophobic binding, covalent bond based binding and indirect binding using various carriers. In addition, this review also describes the release strategies of nucleic acid drugs, including photostimulation-based release, enzyme-responsive release, pH-responsive release, and temperature-responsive release. Finally, the applications and future research directions of hydrogels for delivering nucleic acid drugs in the field of medicine are discussed.

The Role of Nanoparticles in Accelerating Tissue Recovery and Inflammation Control in Physiotherapy Practices

Physiotherapy has significantly evolved since its inception in the late 19th century, expanding into various specializations such as sports, neurology, and wound care. Its primary goal is to restore or enhance bodily functions through therapeutic interventions, aiding in conditions ranging from injuries to chronic pain. Tissue recovery, which involves repair and regeneration, is a critical aspect of physiotherapy. This natural process is influenced by factors like inflammation and injury severity. Nanotechnology, a relatively recent advancement, has transformed medicine, including wound care, through innovations in drug delivery, diagnostics, and anti-inflammatory treatments. Nanoparticles, owing to their small size and enhanced bioavailability, play a crucial role in improving drug delivery, increasing the efficacy of treatments, and promoting faster recovery. In the context of tissue healing, nanoparticles aid in cell proliferation, inflammation control, and scar reduction, among other therapeutic benefits. They are increasingly used in physiotherapy applications, to support tissue regeneration and inflammation management. This review examines the role of nanoparticles in physiotherapy, with a focus on their application in wound healing, muscle recovery, and inflammation control. It discusses various in-vitro and in-vivo studies that have explored the therapeutic potential of nanoparticles in these domains, providing insights into their mechanisms of action and effectiveness in promoting tissue regeneration and managing inflammation in physiotherapy settings.

Debridement efficacy of serine protease and formulated cream by In Vitro assessment against artificial wound eschar

Chronic wounds typically comprise of necrotic tissue and dried secretions, often culminating in the formation of a thick and tough layer of dead skin known as eschar. Removal of eschar is imperative to facilitate wound healing. Conventional approach for eschar removal involves surgical excision and grafting, which can be traumatic and frequently leads to viable tissue damage. There has been growing interest in the use of enzymatic agents for a gentler approach to debridement, utilizing proteolytic enzymes. In this study, a purified intracellular recombinant serine protease from Bacillus sp. (SPB) and its cream formulation were employed to evaluate their ability to degrade artificial wound eschar; composed of collagen, fibrin, and elastin. Degradation was assessed based on percentage weight reduction of eschar biomass, analysis via sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and scanning electron microscopy (SEM). Both SPB and its cream formulation were able to degrade up to 50 % artificial wound eschar, with the SPB cream maintaining its degradation efficiency for up to 24 hours. Additionally, the SPB-based cream demonstrated the ability to hydrolyze proteinaceous components of eschars individually (fibrin and collagen) as determined through qualitative assessment. These findings suggest that SPB holds promise for the debridement of wound eschar.

Enhancing Wound Healing: A Comprehensive Review of Sericin and Chelidonium majus L. as Potential Dressings

Wound healing, a complex physiological process orchestrating intricate cellular and molecular events, seeks to restore tissue integrity. The burgeoning interest in leveraging the therapeutic potential of natural substances for advanced wound dressings is a recent phenomenon. Notably, Sericin, a silk-derived protein, and Chelidonium majus L. (C. majus), a botanical agent, have emerged as compelling candidates, providing a unique combination of natural elements that may revolutionize conventional wound care approaches. Sericin, renowned for its diverse properties, displays unique properties that accelerate the wound healing process. Simultaneously, C. majus, with its diverse pharmacological compounds, shows promise in reducing inflammation and promoting tissue regeneration. As the demand for innovative wound care solutions increases, understanding the therapeutic potential of natural products becomes imperative. This review synthesizes current knowledge on Sericin and C. majus, envisioning their future roles in advancing wound management strategies. The exploration of these natural substances as constituents of wound dressings provides a promising avenue for developing sustainable, effective, and biocompatible materials that could significantly impact the field of wound healing.

Nanocomposite Based on Bacterial Cellulose and Silver Nanoparticles Improve Wound Healing Without Exhibiting Toxic Effect

Wound healing is an important and complex process, containing a multifaceted process governed by sequential yet overlapping phases. Certain treatments can optimize local physiological conditions and improve wound healing. Silver nanoparticles (AgNP) are widely known for their antimicrobial activity. On the other hand, bacterial cellulose (BC) films have been used as a dressing that temporarily substitutes the skin, offering many advantages in optimizing wound healing, in addition to being highly biocompatible. Considering the promising activities of AgNP and BC films, the present study aimed to evaluate the wound healing activity in Wistar Hannover rats using a nanocomposite based on bacterial cellulose containing AgNP (AgBC). In a period of 21 days, its influence on the wound area, microbial growth, histopathological parameters, and collagen content were analyzed. In addition, toxicity indicators were assessed, such as weight gain, water consumption, and creatinine and alanine transaminase levels. After 14 days of injury, the animals treated with AgBC showed a significant increase in wound contraction. The treatment with AgBC significantly reduced the number of microbial colonies compared to other treatments in the first 48 h after the injury. At the end of the 21 experimental days, an average wound contraction rate greater than 97 % in relation to the initial area was observed, in addition to a significant increase in the amount of collagen fibers at the edge of the wounds, lower scores of necrosis, angiogenesis and inflammation, associated with no systemic toxicity. Therefore, it is concluded that the combination of preexisting products to form a new nanocomposite based on BC and AgNP amplified the biological activity of these products, increasing the effectiveness of wound healing and minimizing possible toxic effects of silver.

Eco-Friendly Production of Polyvinyl Alcohol/Carboxymethyl Cellulose Wound Healing Dressing Containing Sericin

Wound dressing production represents an important segment in the biomedical healthcare field, but finding a simple and eco-friendly method that combines a natural compound and a biocompatible dressing production for biomedical application is still a challenge. Therefore, the aim of this study is to develop wound healing dressings that are environmentally friendly, low cost, and easily produced, using natural agents and a physical crosslinking technique. Hydrogel wound healing dressings were prepared from polyvinyl alcohol/carboxymethyl cellulose and sericin using the freeze-thawing method as a crosslinking method. The morphological characterization was carried out by scanning electron microscopy (SEM), whereas the mechanical analysis was carried out by dynamic mechanical analysis (DMA) to test the tensile strength and compression properties. Then, the healing property of the wound dressing material was tested by in vitro and ex vivo tests. The results show a three-dimensional microporous structure with no cytotoxicity, excellent stretchability with compressive properties similar to those of human skin, and excellent healing properties. The proposed hydrogel dressing was tested in vitro with HaCaT keratinocytes and ex vivo with epidermal tissues, demonstrating an effective advantage on wound healing acceleration. Accordingly, this study was successful in developing wound healing dressings using natural agents and a simple and green crosslinking method.

Cerium oxide nanoparticles in wound care: a review of mechanisms and therapeutic applications

Skin wound healing is a complex and tightly regulated process. The frequent occurrence and reoccurrence of acute and chronic wounds cause significant skin damage to patients and impose socioeconomic burdens. Therefore, there is an urgent requirement to promote interdisciplinary development in the fields of material science and medicine to investigate novel mechanisms for wound healing. Cerium oxide nanoparticles (CeO2 NPs) are a type of nanomaterials that possess distinct properties and have broad application prospects. They are recognized for their capabilities in enhancing wound closure, minimizing scarring, mitigating inflammation, and exerting antibacterial effects, which has led to their prominence in wound care research. In this paper, the distinctive physicochemical properties of CeO2 NPs and their most recent synthesis approaches are discussed. It further investigates the therapeutic mechanisms of CeO2 NPs in the process of wound healing. Following that, this review critically examines previous studies focusing on the effects of CeO2 NPs on wound healing. Finally, it suggests the potential application of cerium oxide as an innovative nanomaterial in diverse fields and discusses its prospects for future advancements.

Application of Cinnamomum burmannii Essential Oil in Promoting Wound Healing

Skin wounds, leading to infections and death, have a huge negative impact on healthcare systems around the world. Antibacterial therapy and the suppression of excessive inflammation help wounds heal. To date, the application of wound dressings, biologics and biomaterials (hydrogels, epidermal growth factor, stem cells, etc.) is limited due to their difficult and expensive preparation process. Cinnamomum burmannii (Nees & T. Nees) Blume is an herb in traditional medicine, and its essential oil is rich in D-borneol, with antibacterial and anti-inflammatory effects. However, it is not clear whether Cinnamomum burmannii essential oil has the function of promoting wound healing. This study analyzed 32 main components and their relative contents of essential oil using GC-MS. Then, network pharmacology was used to predict the possible targets of this essential oil in wound healing. We first proved this essential oil's effects in vitro and in vivo. Cinnamomum burmannii essential oil could not only promote the proliferation and migration of skin stromal cells, but also promote M2-type polarization of macrophages while inhibiting the expression of pro-inflammatory cytokines. This study explored the possible mechanism by which Cinnamomum burmannii essential oil promotes wound healing, providing a cheap and effective strategy for promoting wound healing.

Wound healing, scarring and management

Understanding wound healing is imperative for the dermatological physician to optimize surgical outcomes. Poor healing may result in negative functional, cosmetic and psychological sequelae. This review briefly outlines the physiology of wound healing, with a view to improving the management of wounds and scars, and minimizing the long-term scarring complications.

A Nanocomposite Dynamic Covalent Cross-Linked Hydrogel Loaded with Fusidic Acid for Treating Antibiotic-Resistant Infected Wounds

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with high levels of morbidity and is considered a difficult-to-treat infection, often requiring nonstandard treatment regimens and antibiotics. Since over 40% of the emerging antibiotic compounds have insufficient solubility that limits their bioavailability and thus efficacy through oral or intravenous administration, it is crucial that alternative drug delivery products be developed for wound care applications. Existing effective treatments for soft tissue MRSA infections, such as fusidic acid (FA), which is typically administered orally, could also benefit from alternative routes of administration to improve local efficacy and bioavailability while reducing the required therapeutic dose. Herein, we report an antimicrobial poly(oligoethylene glycol methacrylate) (POEGMA)-based composite hydrogel loaded with fusidic acid-encapsulating self-assembled polylactic acid-b-poly(oligo(ethylene glycol) methyl ether methacrylate) (PLA-POEGMA) nanoparticles for the treatment of MRSA-infected skin wounds. The inclusion of the self-assembled nanoparticles (380 nm diameter when loaded with fusidic acid) does not alter the favorable mechanical properties and stability of the hydrogel in the context of its use as a wound dressing, while fusidic acid (FA) can be released from the hydrogel over ∼10 h via a diffusion-controlled mechanism. The antimicrobial studies demonstrate a clear zone of inhibition in vitro and a 1-2 order of magnitude inhibition of bacterial growth in vivo in an MRSA-infected full-thickness excisional murine wound model even at very low antibiotic doses. Our approach thus can both circumvent challenges in the local delivery of hydrophobic antimicrobial compounds and directly deliver antimicrobials into the wound to effectively combat methicillin-resistant infections using a fraction of the drug dose required using other clinically relevant strategies.

Novel Microemulsion Containing Benzocaine and Fusidic Acid Simultaneously: Formulation, Characterization, and In Vitro Evaluation for Wound Healing

Modern drug carrier technologies, such as microemulsions with small droplet sizes and high surface areas, improve the ability of low water solubility active ingredients to permeate and localize. The goal of this study was to create microemulsion formulations for wound healing that contained both fusidic acid (FA), an antibacterial agent, and benzocaine (BNZ), a local anesthetic. Studies on characterization were carried out, including viscosity, droplet size, and zeta potential. The drug-loaded microemulsion had a stable structure with -3.014 ± 1.265 mV of zeta potential and 19.388 ± 0.480 nm of droplet size. In both in vitro release and ex vivo permeability studies, the microemulsion was compared with Fucidin cream and oily BNZ solution. According to the drug release studies, BNZ release from the microemulsion and the BNZ solution showed a similar profile (p > 0.05), while FA release from the microemulsion had a higher drug release compared to Fucidin cream (p < 0.001). The microemulsion presented lower drug permeation (p > 0.05) for both active ingredients, on the other hand, provided higher drug accumulation compared to the control preparations. Moreover, according to the results of in vitro wound healing activity, the microemulsion indicated a dose-dependent wound healing potential with the highest wound healing activity at the highest concentrations. To the best of our knowledge, this developed BNZ- and FA-loaded microemulsion would be a promising candidate to create new opportunities for wound healing thanks to present the active ingredients, which have low water solubility, in a single formulation and achieved higher accumulation than control preparations.

Zirconium-Based Metal-Organic Framework Capable of Binding Proinflammatory Mediators in Hydrogel Form Promotes Wound Healing Process through a Multiscale Adsorption Mechanism

The regulation of proinflammatory mediators has been explored to promote natural healing without abnormal inflammation or autoimmune response induced by their overproduction. However, most efforts to control these mediators have relied on pharmacological substances that are directly engaged in biological cycles. It is believed that functional porous materials removing target mediators provide a new way to promote the healing process using their adsorption mechanisms. In this study, the Zr-based metal-organic frameworks (MOF)-808 (Zr6 O4 (OH)4 (BTC)2 (HCOO)6 ) crystals are found to be effective at removing proinflammatory mediators, such as nitric oxide (NO), cytokines, and reactive oxygen species (ROS) in vitro and in vivo, because of their porous structure and surface affinity. The MOF-808 crystals are applied to an in vivo skin wound model as a hydrogel dispersion. Hydrogel containing 0.2 wt% MOF-808 crystals shows significant improvement in terms of wound healing efficacy and quality over the corresponding control. It is also proven that the mode of action is to remove the proinflammatory mediators in vivo. Moreover, the application of MOF-808-containing hydrogels promotes cell activation, proliferation and inhibits chronic inflammation, leading to increased wound healing quality. These findings suggest that Zr-based MOFs may be a promising drug-free solution for skin problems related to proinflammatory mediators.

In-vivo and in-vitro wound healing and tissue repair effect of Trametes versicolor polysaccharide extract

Regarding different medical benefits of fungi, using the medical mushroom extracts as wound-healing agents is gaining popularity. This study, evaluated the wound healing characteristics of Trametes versicolor. Anti-oxidant activity addressed by employing the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay resulting 53.7% inhibitory effect. Besides, for anti-microbial ability determination, the MIC (Minimum Inhibitory Concentration) of extract measured which Escherichia coli growth was inhibited at 1.1 mg/ml, and Staphylococcus aureus did not grow at 4.38 mg/ml of extract. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method indicated dose dependence of the extract with 63 ± 3% and 28 ± 3% viability at 1250 μg/ml and 156.25 μg/ml of extract, which higher concentration caused higher cell viability. The outcome of gene expression analysis determined that overall expression of FGF2 (Fibroblast Growth Factor 2), IL-1β (Interleukin-1β), and TGF-β1 (Transforming Growth Factor-β1) was 4 times higher at 48 h than at 24 h in treated cells, suggesting a stimulating effect on cell growth. An in-vivo animal model suggested enhanced wound healing process after treatment with 0.01 g of extract. Furthermore, the number of fibroblasts, epidermal thickness, and collagen fiber was respectively 2, 3, and threefold higher in treated mice when compared to untreated mice. The treated wounds of mice showed 100% and 60% of untreated mice of healing within 14 days. The results of this research show promise for the fungus-based wound healing treatments, which may help with tissue regeneration and the healing of cutaneous wounds.

The Physiological Inorganic Polymers Biosilica and Polyphosphate as Key Drivers for Biomedical Materials in Regenerative Nanomedicine

There is a need for novel nanomaterials with properties not yet exploited in regenerative nanomedicine. Based on lessons learned from the oldest metazoan phylum, sponges, it has been recognized that two previously ignored or insufficiently recognized principles play an essential role in tissue regeneration, including biomineral formation/repair and wound healing. Firstly, the dependence on enzymes as a driving force and secondly, the availability of metabolic energy. The discovery of enzymatic synthesis and regenerative activity of amorphous biosilica that builds the mineral skeleton of siliceous sponges formed the basis for the development of successful strategies for the treatment of osteochondral impairments in humans. In addition, the elucidation of the functional significance of a second regeneratively active inorganic material, namely inorganic polyphosphate (polyP) and its amorphous nanoparticles, present from sponges to humans, has pushed forward the development of innovative materials for both soft (skin, cartilage) and hard tissue (bone) repair. This energy-rich molecule exhibits a property not shown by any other biopolymer: the delivery of metabolic energy, even extracellularly, necessary for the ATP-dependent tissue regeneration. This review summarizes the latest developments in nanobiomaterials based on these two evolutionarily old, regeneratively active materials, amorphous silica and amorphous polyP, highlighting their specific, partly unique properties and mode of action, and discussing their possible applications in human therapy. The results of initial proof-of-concept studies on patients demonstrating complete healing of chronic wounds are outlined.

The heterogeneity and complexity of skin surface lipids in human skin health and disease

The outermost epidermal layer of the skin, the stratum corneum, is not simply a barrier that safeguards skin integrity from external insults and invaders, it is also a delicately integrated interface composed of firm, essentially dead corneocytes and a distinctive lipid matrix. Together, the stratum corneum lipid matrix and sebum lipids derived from sebaceous glands give rise to a remarkably complex but quite unique blend of skin surface lipids that demonstrates tremendous heterogeneity and provides the skin with its indispensable protective coating. The stratum corneum lipid matrix is composed primarily of three major lipid classes: ceramides, non-esterified fatty acids and cholesterol, whereas sebum is a waxy mixture predominantly composed of acylglycerols, wax esters, non-esterified fatty acids, squalene, cholesterol and cholesterol esters. The balance of these skin surface lipids in terms of their relative abundance, composition, molecular organisation and dynamics, and their intricate interactions play a crucial role in the maintenance of healthy skin. For that reason, even minuscule alterations in skin surface lipid properties or overall lipid profile have been implicated in the aetiology of many common skin diseases including atopic dermatitis, psoriasis, xerosis, ichthyosis and acne. Novel lipid-based interventions aimed at correcting the skin surface lipid abnormalities have the potential to repair skin barrier integrity and the symptoms associated with such skin diseases, even though the exact mechanisms of lipid restoration remain elusive.

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.

Development and characterization of a poloxamer hydrogel composed of human mesenchymal stromal cells (hMSCs) for reepithelization of skin injuries

Wound healing is a natural physiological reaction to tissue injury. Hydrogels show attractive advantages in wound healing not only due to their biodegradability, biocompatibility and permeability but also because provide an excellent environment for cell migration and proliferation. The main objective of the present study was the design and characterization of a hydrogel loaded with human mesenchymal stromal cells (hMSCs) for use in would healing of superficial skin injures. Poloxamer 407® was used as biocompatible biomaterial to embed hMSCs. The developed hydrogel containing 20 % (w/w) of polymer resulted in the best formulation with respect to physical, mechanical, morphological and biological properties. Its high swelling capacity confirmed the hydrogel's capacity to absorb wounds' exudate. LIVE/DEAD® assay confirm that hMSCs remained viable for at least 48 h when loaded into the hydrogels. Adding increasing concentrations of hMSCs-loaded hydrogel to the epithelium did not affect keratinocytes' viability and healing capacity and all wound area was closed in less than one day. Our study opens opportunities to exploit poloxamer hydrogels as cell carriers for the treatment of skin superficial wound.

Assessment of antimicrobial activity and In Vitro wound healing potential of ZnO nanoparticles synthesized with Capparis spinosa extract

Agents that will accelerate wound healing maintain their clinical importance in all aspects. The aim of this study is to determine the antimicrobial activity of zinc oxide nanoparticles (ZnO NPs) ZnO nanoparticles obtained by green synthesis from Capparis spinosa L. extract and their effect on in vitro wound healing. ZnO NPs were synthesized and characterized using Capparis spinosa L. extract. ZnO NPs were tested against nine ATCC-coded pathogen strains to determine antimicrobial activity. The effects of different doses (0.0390625-20 µg/mL) of NPs on cell viability were determined by MTT assay. The effect of ZnO NPs doses (0.0390625 µg/mL, 0.078125 µg/mL, 0.15625 µg/mL, 0.3125 µg/mL, 0.625 µg/mL, 1.25 µg/mL) that increase proliferation and migration on wound healing was investigated in an in vitro wound experiment. Cell culture medium obtained from the in vitro wound assay was used for biochemical analysis, and plate alcohol-fixed cells were used for immunohistochemical staining. It was determined that NPs formed an inhibition zone against the tested Gram-positive bacteria. The ZnO NPs doses determined in the MTT test provided faster wound closure in in-vitro conditions compared to the DMSO group. Biochemical analyses showed that inflammation and oxidative status decreased, while antioxidant levels increased in ZnO NPs groups. Immunohistochemical analyses showed increased expression levels of Bek/FGFR2, IGF, and TGF-β associated with wound healing. The findings reveal the antimicrobial effect of ZnO nanoparticles obtained using Capparis spinosa L. extract in vitro and their potential applications in wound healing.

Bioadhesive and Injectable Hydrogels and Their Correlation with Mesenchymal Stem Cells Differentiation for Cartilage Repair: A Mini-Review

Injectable bioadhesive hydrogels, known for their capacity to carry substances and adaptability in processing, offer great potential across various biomedical applications. They are especially promising in minimally invasive stem cell-based therapies for treating cartilage damage. This approach harnesses readily available mesenchymal stem cells (MSCs) to differentiate into chondrocytes for cartilage regeneration. In this review, we investigate the relationship between bioadhesion and MSC differentiation. We summarize the fundamental principles of bioadhesion and discuss recent trends in bioadhesive hydrogels. Furthermore, we highlight their specific applications in conjunction with stem cells, particularly in the context of cartilage repair. The review also encompasses a discussion on testing methods for bioadhesive hydrogels and direct techniques for differentiating MSCs into hyaline cartilage chondrocytes. These approaches are explored within both clinical and laboratory settings, including the use of genetic tools. While this review offers valuable insights into the interconnected aspects of these topics, it underscores the need for further research to fully grasp the complexities of their relationship.

Stem Cells and Exosome Applications for Cutaneous Wound Healing: From Ground to Microgravity Environment

The increasing number of astronauts entering microgravity environments for long-term space missions has resulted in serious health problems, including accidental injury and trauma. Skin, as the largest organ and outermost layer of the human body, has the ability to self-renew and withstand a variety of harmful biological and environmental influences. Recent spaceflight experiments and simulated studies have begun to concern the effects of microgravity on the growth of skin cells and the process of cutaneous wound healing. However, the mechanisms of the adverse effects of microgravity on skin cells and potential intervention measures are still limited. Stem cells and their exosomes provide unique opportunities for the cutaneous wound healing as they have been used to improve skin repair. This review discusses the effects of microgravity on wound healing, from cell morphological changes to molecular level alterations. Furthermore, the current research on wound healing treatment utilizing stem cells and their exosomes on the ground is summarized. Finally, this review proposes promising therapeutic strategies using stem cells or exosomes for wound healing in the microgravity environment. Graphical Abstract.

Modern Approaches in Wounds Management

Wound management represents a well-known continuous challenge and concern of the global healthcare systems worldwide. The challenge is on the one hand related to the accurate diagnosis, and on the other hand to establishing an effective treatment plan and choosing appropriate wound care products in order to maximize the healing outcome and minimize the financial cost. The market of wound dressings is a dynamic field which grows and evolves continuously as a result of extensive research on developing versatile formulations with innovative properties. Hydrogels are one of the most attractive wound care products which, in many aspects, are considered ideal for wound treatment and are widely exploited for extension of their advantages in healing process. Smart hydrogels (SHs) offer the opportunities of the modulation physico-chemical properties of hydrogels in response to external stimuli (light, pressure, pH variations, magnetic/electric field, etc.) in order to achieve innovative behavior of their three-dimensional matrix (gel-sol transitions, self-healing and self-adapting abilities, controlled release of drugs). The SHs response to different triggers depends on their composition, cross-linking method, and manufacturing process approach. Both native or functionalized natural and synthetic polymers may be used to develop stimuli-responsive matrices, while the mandatory characteristics of hydrogels (biocompatibility, water permeability, bioadhesion) are preserved. In this review, we briefly present the physiopathology and healing mechanisms of chronic wounds, as well as current therapeutic approaches. The rational of using traditional hydrogels and SHs in wound healing, as well as the current research directions for developing SHs with innovative features, are addressed and discussed along with their limitations and perspectives in industrial-scale manufacturing.

Comparative Study of the Efficacy of EHO-85, a Hydrogel Containing Olive Tree (Olea europaea) Leaf Extract, in Skin Wound Healing

Olive tree (Olea europaea) leaf extract (OELE) has important antioxidant and anti-inflammatory properties, supporting its use in human clinical practice. We recently designed an amorphous hydrogel called EHO-85 (EHO indicates olive leaf extract in Spanish) containing OELE for skin ulcer treatments. Yet, its effectiveness has not been previously compared with other products used in routine clinical practice. This is necessary to evaluate its potential translation to the human clinic. Thus, in this study, the effect of EHO-85 on healing was evaluated in comparison with treatments containing Indian/Asiatic pennywort (Centella asiatica), hyaluronic acid, or dexpanthenol in a rat model. The speed of wound closure and histological parameters after seven and 14 days were analyzed. All treatments accelerated wound closure, but there were differences between them. Dexpanthenol after seven days produced the highest epithelialization and the lowest inflammation and vascularization. EHO-85 also promoted epithelialization and reduced vascularization. After 14 days, wounds treated with EHO-85 showed less inflammation and higher levels of collagen in the extracellular matrix. This indicates a higher degree of maturity in the regenerated tissue. In conclusion, the effect of EHO-85 on healing was equal to or superior to that of other treatments routinely used in human clinical practice. Therefore, these results, together with previous data on the effects of this hydrogel on ulcer healing in humans, indicate that EHO-85 is a suitable, low-cost, and efficient therapeutic option for wound healing.

Effect of Betulin Colloidal Particles on Proliferation and Cytokine Secretion of Human Skin Fibroblasts

The aim of the study was to obtain untreated and treated betulin colloidal particles and assess their effect on the viability, morphology, proliferation and cytokine secretion of human dermal fibroblasts. To improve bioavailability, betulin treatment was performed by an antisolvent precipitation technique. The average particle size after treatment in the aqueous dispersion decreased from 552.9 ± 11.3 to 278.2 ± 1.6 nm. Treated betulin colloidal particles showed no cytotoxicity up to a concentration of 400 µg·mL-1 in the colorimetric tetrazolium salt viability test (CCK-8). Moreover, the cell morphology was not changed in the presence of betulin colloidal particles at a concentration range from 0.78 to 400 µg·mL-1. The obtained results also show that betulin particles induce the secretion of the proinflammatory and angiogenesis-stimulating cytokine IL-8. However, further studies would be required to clarify the mechanism of IL-8 secretion induction.

Bile Acid Sequestrants Based on Natural and Synthetic Gels

Bile acid sequestrants (BASs) are non-systemic therapeutic agents used for the management of hypercholesterolemia. They are generally safe and not associated with serious systemic adverse effects. Usually, BASs are cationic polymeric gels that have the ability to bind bile salts in the small intestine and eliminate them by excretion of the non-absorbable polymer-bile salt complex. This review gives a general presentation of bile acids and the characteristics and mechanisms of action of BASs. The chemical structures and methods of synthesis are shown for commercial BASs of first- (cholestyramine, colextran, and colestipol) and second-generation (colesevelam and colestilan) and potential BASs. The latter are based on either synthetic polymers such as poly((meth)acrylates/acrylamides), poly(alkylamines), poly(allylamines) and vinyl benzyl amino polymers or biopolymers, such as cellulose, dextran, pullulan, methylan, and poly(cyclodextrins). A separate section is dedicated to molecular imprinting polymers (MIPs) because of their great selectivity and affinity for the template molecules used in the imprinting technique. Focus is given to the understanding of the relationships between the chemical structure of these cross-linked polymers and their potential to bind bile salts. The synthetic pathways used in obtaining BASs and their in vitro and in vivo hypolipidemic activities are also introduced.

Enhancing Wound Healing: A Novel Topical Emulsion Combining CW49 Peptide and Lavender Essential Oil for Accelerated Regeneration and Antibacterial Protection

Wound healing is a complex process involving blood cells, extracellular matrix, and parenchymal cells. Research on biomimetics in amphibian skin has identified the CW49 peptide from Odorrana grahami, which has been demonstrated to promote wound regeneration. Additionally, lavender essential oil exhibits anti-inflammatory and antibacterial activities. Given these considerations, we propose an innovative emulsion that combines the CW49 peptide with lavender oil. This novel formulation could serve as a potent topical treatment, potentially fostering the regeneration of damaged tissues and providing robust antibacterial protection for skin wounds. This study investigates the physicochemical properties, biocompatibility, and in vitro regenerative capacity of the active components and the emulsion. The results show that the emulsion possesses appropriate rheological characteristics for topical application. Both the CW49 peptide and lavender oil exhibit high viability in human keratinocytes, indicating their biocompatibility. The emulsion induces hemolysis and platelet aggregation, an expected behavior for such topical treatments. Furthermore, the lavender-oil emulsion demonstrates antibacterial activity against both Gram-positive and Gram-negative bacterial strains. Finally, the regenerative potential of the emulsion and its active components is confirmed in a 2D wound model using human keratinocytes. In conclusion, the formulated emulsion, which combines the CW49 peptide and lavender oil, shows great promise as a topical treatment for wound healing. Further research is needed to validate these findings in more advanced in vitro models and in vivo settings, potentially leading to improved wound-care management and novel therapeutic options for patients with skin injuries.

Exosomes: A Promising Strategy for Repair, Regeneration and Treatment of Skin Disorders

The skin is the organ that serves as the outermost layer of protection against injury, pathogens, and homeostasis with external factors; in turn, it can be damaged by factors such as burns, trauma, exposure to ultraviolet light (UV), infrared radiation (IR), activating signaling pathways such as Toll-like receptors (TLR) and Nuclear factor erythroid 2-related factor 2 (NRF2), among others, causing a need to subsequently repair and regenerate the skin. However, pathologies such as diabetes lengthen the inflammatory stage, complicating the healing process and, in some cases, completely inhibiting it, generating susceptibility to infections. Exosomes are nano-sized extracellular vesicles that can be isolated and purified from different sources such as blood, urine, breast milk, saliva, urine, umbilical cord bile cells, and mesenchymal stem cells. They have bioactive compounds that, thanks to their paracrine activity, have proven to be effective as anti-inflammatory agents, inducers of macrophage polarization and accelerators of skin repair and regeneration, reducing the possible complications relating to poor wound repair, and prolonged inflammation. This review provides information on the use of exosomes as a promising therapy against damage from UV light, infrared radiation, burns, and skin disorders.

Nanocrystals in cosmetics and cosmeceuticals by topical delivery

The main issues with local delivery of cosmetics are their high sensitivity and limited drug loading of active pharmaceutical ingredient. Nanocrystal technology offers consumers cutting-edge and effective products and exhibits enormous development potential in the beauty business as a new delivery method to address the issue of low solubility and low permeability of sensitive chemicals. In this review, we described the processes for making NCs, along with the impacts of loading and the uses of different carriers. Among them, nanocrystalline loaded gel and emulsion are widely used and may further improve the stability of the system. Then, we introduced the beauty efficacy of drug NCs from five aspects: anti-inflammation and acne, anti-bacterial, lightening and freckle removal, anti-aging as well as UV protection. Following that, we presented the current scenario about stability and safety. Finally, the challenges and vacancy were discussed along with the potential uses of NCs in the cosmetics industry. This review serves as a resource for the advancement of nanocrystal technology in the cosmetics sector.

A Brief Review on Cerium Oxide (CeO2NPs)-Based Scaffolds: Recent Advances in Wound Healing Applications

The process of wound healing is complex and involves the interaction of multiple cells, each with a distinct role in the inflammatory, proliferative, and remodeling phases. Chronic, nonhealing wounds may result from reduced fibroblast proliferation, angiogenesis, and cellular immunity, often associated with diabetes, hypertension, vascular deficits, immunological inadequacies, and chronic renal disease. Various strategies and methodologies have been explored to develop nanomaterials for wound-healing treatment. Several nanoparticles such as gold, silver, cerium oxide and zinc possess antibacterial properties, stability, and a high surface area that promotes efficient wound healing. In this review article, we investigate the effectiveness of cerium oxide nanoparticles (CeO₂NPs) in wound healing-particularly the effects of reducing inflammation, enhancing hemostasis and proliferation, and scavenging reactive oxygen species. The mechanism enables CeO₂NPs to reduce inflammation, modulate the immunological system, and promote angiogenesis and tissue regeneration. In addition, we investigate the efficacy of cerium oxide-based scaffolds in various wound-healing applications for creating a favorable wound-healing environment. Cerium oxide nanoparticles (CeO₂NPs) exhibit antioxidant, anti-inflammatory, and regenerative characteristics, enabling them to be ideal wound healing material. Investigations have shown that CeO₂NPs can stimulate wound closure, tissue regeneration, and scar reduction. CeO₂NPs may also reduce bacterial infections and boost wound-site immunity. However, additional study is needed to determine the safety and efficacy of CeO₂NPs in wound healing and their long-term impacts on human health and the environment. The review reveals that CeO₂NPs have promising wound-healing properties, but further study is needed to understand their mechanisms of action and ensure their safety and efficacy.

Transdermal drug delivery via microneedles to mediate wound microenvironment

Cutaneous wound healing is a complex process, while modulating the wound microenvironment has become an essential therapeutic goal. In clinics, advanced dressings or dermal templates can promote wound healing but their ability in mediating wound microenvironment is limited. In the last decade, microneedle (MN) array patches have emerged as a new class of wound dressings. These dressings enable non-invasive transdermal and precise medication delivery. Combined with smart materials, MN additionally allows real-time monitoring of wound site markers such as inflammatory factors, oxygen levels, vascularization, pH and temperature, etc., while releasing therapeutic molecules responsively to the wound site. In this review, the MN-based strategies were reviewed for modulating wound microenvironment via introducing the main characteristics of the wound microenvironment and various types of MN-based delivery systems. Additionally, the progress and future trends in the application of MNs in mediating wound microenvironments are also discussed.

High Expansion Auxetic Skin Graft Simulants for Severe Burn Injury Mitigation

Burn injuries are commonly treated with split-thickness skin grafting. However, low expansions offered by spilt-thickness skin grafting inhibit the treatment of large and severe burn injuries when limited donor skin is available. To overcome this gap, in this work, it was attempted to study the expansion potential of skin grafts with novel auxetic incisions with rotating rectangle (RR), honeycomb (HC), alternating slit (AS), H-shaped (HS), Y-shaped (YS), and I-shaped (IS) unit cells, through development of skin graft simulants. Clinically relevant biaxial load testing was conducted to estimate the stress-strain response, void area, and meshing ratio. Moreover, hyperelastic constitutive models were employed to characterize the non-linear biomechanical behavior of the skin graft simulants. The maximum void area increase was observed in the HS skin graft simulant, indicating low skin cover. Overall, the IS auxetic skin graft design exhibited meshing ratio higher than traditional grafts (>3:1), low void area and stresses, which can be beneficial for large skin cover and burn wound healing. With further optimization and clinical tests, the auxetic skin graft designs may find a place with the graft manufacturers for fabrication of grafts with better surgical outcomes for severe burn injuries.

Recent advances in hydrogels for preventing tumor recurrence

Malignant tumors remain a high-risk disease with high mortality all over the world. Among all the cancer treatments, surgery is the primary approach in the clinical treatment of tumors. However, tumor invasion and metastasis pose challenges for complete tumor resection, accompanied by high recurrence rates and reduced quality of life. Hence, there is an urgent need to explore effective adjuvant therapies to prevent postoperative tumor recurrence and relieve the pain of the patients. Nowadays, the booming local drug delivery systems which can be applied as postoperative adjuvant therapies have aroused people's attention, along with the rapid development in the pharmaceutical and biological materials fields. Hydrogels are a kind of unique carrier with prominent biocompatibility among a variety of biomaterials. Due to their high similarity to human tissues, hydrogels which load drugs/growth factors can prevent rejection reactions and promote wound healing. In addition, hydrogels are able to cover the postoperative site and maintain sustained drug release for the prevention of tumor recurrence. In this review, we survey controlled drug delivery hydrogels such as implantable, injectable and sprayable formulations and summarize the properties required for hydrogels used as postoperative adjuvant therapies. The opportunities and challenges in the design and clinical application of these hydrogels are also elaborated.

Healing Wounds Efficiently with Biomimetic Soft Matter: Injectable Self-Healing Neutral Glycol Chitosan/Dibenzaldehyde-Terminated Poly(ethylene glycol) Hydrogel with Inherent Antibacterial Properties

The high prevalence of acquiring skin wounds, along with the emergence of antibiotic-resistant strains that lead to infections, impose a threat to the physical, mental, and socioeconomic health of society. Among the wide array of wound dressings developed, hydrogels are regarded as a biomimetic soft matter of choice owing to their ability to provide a moist environment ideal for healing. Herein, neutral glycol chitosan (GC) was cross-linked via imine bonds with varying concentrations of dibenzaldehyde-terminated polyethylene glycol (DP) to give glycol chitosan/dibenzaldehyde-terminated polyethylene glycol hydrogels (GC/DP). These dynamic Schiff base linkages (absorption peak at 1638 cm^-1) within the hydrogel structure endowed their ability to recover from damage as characterized by high-low strain exposure in continuous step strain rheology. Along with their good injectability and biodegradability, the hydrogels exhibited remarkable inhibition against E. coli, P. aeruginosa, and S. aureus. GC/DP hydrogels demonstrated high LC50 values in vivo using zebrafish embryos as a model system due to their relative biocompatibility and a remarkable 93.4 ± 0.88% wound contraction at 30-dpw against 49.1 ± 3.40% of the control. To the best of our knowledge, this is the first study that developed injectable glycol chitosan/dibenzaldehyde-terminated polyethylene glycol self-healing hydrogels for application in wound healing with intrinsic bacteriostatic properties against the three bacteria.

Biomaterials Based on Chitosan and Polyvinyl Alcohol as a Drug Delivery System with Wound-Healing Effects

The excellent biological properties of chitosan (CS) together with the increased oxygen permeability of polyvinyl alcohol (PVA) were the prerequisites for the creation of a wound healing dressing that would also function as a system for L-arginine (L-arg) and caffeine (Caff) delivery. Using the freezing/thawing method, 12 hydrogels were obtained in PVA:CS polymer ratios of 90:10, 75:25, and 60:40, and all were loaded with L-arg, Caff, and the mixture of L-arg and Caff, respectively. Afterwards, an inorganic material (zeolite-Z) was added to the best polymeric ratio (75:25) and loaded with active substances. The interactions between the constituents of the hydrogels were analyzed by FTIR spectroscopy, the uniformity of the network was highlighted by the SEM technique, and the dynamic water vapor sorption capacity was evaluated. In the presence of the inorganic material, the release profile of the active substances is delayed, and in vitro permeation kinetics proves that the equilibrium state is not reached even after four hours. The synergy of the constituents in the polymer network recommends that they be used in medical applications, such as wound healing dressings.

Release of Bioactive Molecules from Graphene Oxide-Alginate Hybrid Hydrogels: Effect of Crosslinking Method

To investigate the influence of crosslinking methods on the releasing performance of hybrid hydrogels, we synthesized two systems consisting of Graphene oxide (GO) as a functional element and alginate as polymer counterpart by means of ionic gelation (physical method, HA−GOP) and radical polymerization (chemical method, HA−GOC). Formulations were optimized to maximize the GO content (2.0 and 1.15% for HA−GOP and HA−GOC, respectively) and Curcumin (CUR) was loaded as a model drug at 2.5, 5.0, and 7.5% (by weight). The physico-chemical characterization confirmed the homogeneous incorporation of GO within the polymer network and the enhanced thermal stability of hybrid vs. blank hydrogels. The determination of swelling profiles showed a higher swelling degree for HA−GOC and a marked pH responsivity due to the COOH functionalities. Moreover, the application of external voltages modified the water affinity of HA−GOC, while they accelerated the degradation of HA−GOP due to the disruption of the crosslinking points and the partial dissolution of alginate. The evaluation of release profiles, extensively analysed by the application of semi-empirical mathematical models, showed a sustained release from hybrid hydrogels, and the possibility to modulate the releasing amount and rate by electro-stimulation of HA−GOC.