Acceleration of dermal wound healing by using electrospun curcumin-loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) fibrous mats

An Overview of Wound Dressing Materials

Wounds are an increasing global concern, mainly due to a sedentary lifestyle, frequently associated with the occidental way of life. The current prevalence of obesity in Western societies, leading to an increase in type II diabetes, and an elderly population, is also a key factor associated with the problem of wound healing. Therefore, it stands essential to find wound dressing systems that allow for reestablishing the skin integrity in the shortest possible time and with the lowest cost, avoiding further damage and promoting patients' well-being. Wounds can be classified into acute or chronic, depending essentially on the duration of the healing process, which is associated withextent and depth of the wound, localization, the level of infection, and the patient's health status. For each kind of wound and respective healing stage, there is a more suitable dressing. The aim of this review was to focus on the possible wound dressing management, aiming for a more adequate healing approach for each kind of wound.

Chitosan/Virgin Coconut Oil-Based Emulsions Doped with Photosensitive Curcumin Loaded Capsules: A Functional Carrier to Topical Treatment

In recent years, there has been a growing interest in developing smart drug delivery systems based on natural resources combined with stimulus-sensitive elements. This trend aims to formulate innovative and sustainable delivery platforms tailored for topical applications. This work proposed the use of layer-by-layer (LbL) methodology to fabricate biocompatible photo-responsive multilayer systems. These systems are composed of a polyoxometalate inorganic salt (POM) ([NaP5W30O110]14-) and a natural origin polymer, chitosan (CHT). Curcumin (CUR), a natural bioactive compound, was incorporated to enhance the functionality of these systems during the formation of hollow capsules. The capsules produced, with sizes between 2-5µm (SEM), were further dispersed into CHT/VCO (virgin coconut oil) emulsion solutions that were casted into molds and dried at 37 °C for 48 h. The system presented a higher water uptake in PBS than in acidic conditions, still significantly lower than that earlier reported to other CHT/VCO-based systems. The drug release profile is not significantly influenced by the medium pH reaching a maximum of 37% ± 1% after 48 h. The antioxidant performance of the designed structures was further studied, suggesting a synergistic beneficial effect resulting from CUR, POM, and VCO individual bioactivities. The increased amount of those excipients released to the media over time promoted an increase in the antioxidant activity of the system, reaching a maximum of 38.1% ± 0.1% after 48 h. This work represents a promising step towards developing advanced, sustainable drug delivery systems for topical applications.

The food and biomedical applications of curcumin-loaded electrospun nanofibers: A comprehensive review

Encapsulating curcumin (CUR) in nanocarriers such as liposomes, polymeric micelles, silica nanoparticles, protein-based nanocarriers, solid lipid nanoparticles, and nanocrystals could be efficient for a variety of industrial and biomedical applications. Nanofibers containing CUR represent a stable polymer-drug carrier with excellent surface-to-volume ratios for loading and cell interactions, tailored porosity for controlled CUR release, and diverse properties that fit the requirements for numerous applications. Despite the mentioned benefits, electrospinning is not capable of producing fibers from multiple polymers and biopolymers, and the product's effectiveness might be affected by various machine- and material-dependent parameters like the voltage and the flow rate of the electrospinning process. This review delves into the current and innovative recent research on nanofibers containing CUR and their various applications.

Transforming Wound Management: Nanomaterials and Their Clinical Impact

Wound healing is a complex process that can be further complicated in chronic wounds, leading to prolonged healing times, high healthcare costs, and potential patient morbidity. Nanotechnology has shown great promise in developing advanced wound dressings that promote wound healing and prevent infection. The review article presents a comprehensive search strategy that was applied to four databases, namely Scopus, Web of Science, PubMed, and Google Scholar, using specific keywords and inclusion/exclusion criteria to select a representative sample of 164 research articles published between 2001 and 2023. This review article provides an updated overview of the different types of nanomaterials used in wound dressings, including nanofibers, nanocomposites, silver-based nanoparticles, lipid nanoparticles, and polymeric nanoparticles. Several recent studies have shown the potential benefits of using nanomaterials in wound care, including the use of hydrogel/nano silver-based dressings in treating diabetic foot wounds, the use of copper oxide-infused dressings in difficult-to-treat wounds, and the use of chitosan nanofiber mats in burn dressings. Overall, developing nanomaterials in wound care has complemented nanotechnology in drug delivery systems, providing biocompatible and biodegradable nanomaterials that enhance wound healing and provide sustained drug release. Wound dressings are an effective and convenient method of wound care that can prevent wound contamination, support the injured area, control hemorrhaging, and reduce pain and inflammation. This review article provides valuable insights into the potential role of individual nanoformulations used in wound dressings in promoting wound healing and preventing infections, and serves as an excellent resource for clinicians, researchers, and patients seeking improved healing outcomes.

Curcumin Release from Biomaterials for Enhanced Tissue Regeneration Following Injury or Disease

Curcumin, a bioactive phenol derived from turmeric, is an antioxidant, anti-inflammatory, and antibacterial molecule. Although curcumin exhibits beneficial effects in its innate form, it is highly hydrophobic, which leads to poor water solubility and, consequently, low bioavailability. The lack of bioavailability limits curcumin's effectiveness as a treatment and restricts its use in clinical applications. Furthermore, to achieve beneficial, clinically relevant results, high doses of curcumin are required for systemic administration. Many researchers have utilized biomaterial carriers, including electrospun fibers, nanoparticles, hydrogels, and composite scaffolds, to overcome curcumin's principle therapeutic limitation of low bioavailability. By using biomaterials to deliver curcumin directly to injury sites, researchers have harnessed the beneficial natural properties of curcumin while providing scaffolding to support tissue regeneration. This review will provide an in-depth overview of the literature that utilizes biomaterial delivery of curcumin for tissue regeneration in injury and disease models.

Polyethylenimine-grafted mesoporous silica nanocarriers markedly enhance the bactericidal effect of curcumin against Staphylococcus aureus biofilm

The recalcitrant nature of biofilms makes biofilm-associated infections difficult to treat in modern medicine. Biofilms have a high vulnerability to antibiotics and a limited repertoire of antibiotics could act on matured biofilms. This issue has resulted in a gradual paradigm shift in drug discovery and therapy, with anti-biofilm compounds being sought alongside new drug carriers. A potential solution to biofilm-associated infections is to employ antibiofilm treatments, which can attack biofilms from many fronts. Nanocarriers are promising in this regard because they can be entrapped within biofilm matrix, target biofilm matrix, and provide local drug delivery to inhibit biofilm formation. In this study, curcumin as an herbal extract was loaded onto hyperbranched polyethylenimine-grafted mesoporous silica nanoparticles (F-MSN-PEI/Cur) and antibiofilm investigations were performed. The F-MSN-PEI/Cur design has the potential to repurpose curcumin as an antibiofilm agent by increasing its solubility and lowering the required doses for the destruction of matured biofilms as well as suppressing biofilm development. Using imaging and spectroscopic techniques, we assessed the interaction of F-MSN-PEI/Cur with Staphylococcus aureus bacterial cells and determined the impact of F-MSN-PEI/Cur on eradicating matured biofilms and suppressing biofilm development. The F-MSN-PEI/Cur design is highly cytocompatible, as observed by the cytotoxicity screening investigations on L929 mouse fibroblast cell line. Our findings show that F-MSN-PEI/Cur design reduces the bacterial cell viability, inhibits biofilm formation, and induces biofilm eradication, which is attributed to F-MSN-PEI/Cur design having the potential to repurpose the antibiofilm activity of curcumin-herbal extract.

Nanoengineered therapeutic scaffolds for burn wound management

BACKGROUND

Wound healing is a complex process, and selecting an appropriate treatment is crucial and varies from one wound to another. Among injuries, burn wounds are more challenging to treat. Different dressings and scaffolds come into play when skin is injured. These scaffolds provide the optimum environment for wound healing. With the advancements of nanoengineering, scaffolds have been engineered to improve wound healing with lower fatality rates.

OBJECTIVES

Nanoengineered systems have emerged as one of the promising candidates for burn wound management. This review paper aims to provide an in-depth understanding of burn wounds and the role of nanoengineering in burn wound management. The advantages of nanoengineered scaffolds, their properties, and their proven effectiveness have been discussed. Nanoparticles and nanofibers-based nanoengineered therapeutic scaffolds provide optimum protection, infection management, and accelerated wound healing due to their unique characteristics. These scaffolds increase cell attachment and proliferation for desired results.

RESULTS

The literature review suggested that the utilization of nanoengineered scaffolds has accelerated burn wound healing. Nanofibers provide better cell attachment and proliferation among different nanoengineered scaffolds due to their 3D structure mimics the body's extracellular matrix.

CONCLUSION

With the application of these advanced nanoengineered scaffolds, better burn wound management is possible due to sustained drug delivery, better cell attachment, and an infection-free environment.

Therapeutic effects of EGF-modified curcumin/chitosan nano-spray on wound healing

Dermal injury, including trauma, surgical incisions, and burns, remain the most prevalent socio-economical health care issue in the clinic. Nanomedicine represents a reliable administration strategy that can promote the healing of skin lesions, but the lack of effective drug delivery methods can limit its effectiveness. In this study, we developed a novel nano-drug delivery system to treat skin defects through spraying. We prepared curcumin-loaded chitosan nanoparticles modified with epidermal growth factor (EGF) to develop an aqueous EGF-modified spray (EGF@CCN) for the treatment of dermal wounds. In vitro assays showed that the EGF@CCN displayed low cytotoxicity, and that curcumin was continuously and slowly released from the EGF@CCN. In vivo efficacy on wound healing was then evaluated using full-thickness dermal defect models in Wistar rats, showing that the EGF@CCN had significant advantages in promoting wound healing. On day 12 post-operation, skin defects in the rats of the EGF@CCN group were almost completely restored. These effects were related to the activity of curcumin and EGF on skin healing, and the high compatibility of the nano formulation. We therefore conclude that the prepared nano-scaled EGF@CCN spray represents a promising strategy for the treatment of dermal wounds.

Synthesis of nano-fibers containing nano-curcumin in zein corn protein and its physicochemical and biological characteristics

Curcumin contains many biological activities as a natural bioactive substance, however, its low solubility stands as a huge bioavailability disadvantage. Recently, different methods have been developed for utilizing the tremendous medicinal properties of this material. In this study, an Oil/Water nano-emulsion of curcumin (Nano-CUR) has been woven in zein polymer at three percentages of 5%, 10%, and 15% (v/v). We have investigated the physicochemical properties of nanofibers (NFs) including FESEM, FTIR, tensile strength, encapsulation efficiency, and release profile, as well as biological properties. According to the data, the NFs have been observed to become significantly thinner and more uniformed as the involved percentage of Nano-CUR had been increased from 5 to 15%. It is considerable that the tensile strength can be increased by heightening the existing Nano-CUR from 5% towards 15%. The resultant NFs of zein/Nano-CUR 15% have exhibited higher in vitro release and lower encapsulation efficiency than the other evaluated zein/Nano-CUR NFs. It has been confirmed through the performed viability and antioxidant studies that zein/Nano-CUR 10% NFs are capable of providing the best conditions for cell proliferation. Considering the mentioned facts, this work has suggested that Nano-CUR can be successfully woven in zein NFs and maintain their biological properties.

Curcumin nanoparticles incorporated in PVA/collagen composite films promote wound healing

Skin repair remains a common problem in plastic surgery. Wound dressing plays an important role in promoting local skin healing and has been widely studied. This study aimed to manufacture a composite film (CPCF) containing curcumin nanoparticles, collagen, and polyvinyl alcohol (PVA) to effectively promote the healing of skin wounds. Sustained drug release from the composite film provides long-term protection and treatment for skin wounds. Both antibacterial property and good histocompatibility of the CPCF were examined by analyzing antibacterial activity and cytotoxicity to validate its applicability for wound management. Moreover, in vivo studies proved that the CPCF had a rapid healing rate of 98.03%±0.79% and mature epithelialization on day 15 after surgery. Obvious hair follicles and earlier re-epithelialization was also noticed in the CPCF group using H&E staining. The result of Masson’s trichrome staining confirmed that CPCF could promote the formation of collagen fibers. In summary, CPCF may be promising as a wound dressing agent in wound management owing to its rapid wound-healing effects.

Antibacterial Properties and pH Sensitive Swelling of Insitu Formed Silver-Curcumin Nanocomposite Based Chitosan Hydrogel

A simple method was used to prepare curcumin/silver nanocomposite based chitosan hydrogel. In an alkaline medium, chitosan and chitosan nanocomposite hydrogels were prepared using the physical crosslinking method. The prepared hydrogels were stable for a long period at room temperature. In one step, silver nanoparticles were prepared insitu using silver nitrate solution and curcumin oxide within the hydrogel network formation. In the meantime, curcumin compound served as both a reducing and stabilizing agent. The structure and surface morphology of nanocomposite hydrogels were characterized by FTIR, SEM, and EDX analysis confirmed the formation of silver nanoparticles within the hydrogel network. Moreover, Images of TEM showed a spherical shape of silver nanoparticles with an average size of 2–10 nm within the matrix of the hydrogel. The formation mechanism of nanocomposite based hydrogel was reported. Besides that, the effect of chitosan and silver nitrate concentrations were studied. The swelling capacity of the prepared nanocomposite hydrogels was also performed at different pH of 4, 7, and 9. From the experimental results, the swelling capacity of hydrogels depends on the concentrations of chitosan and silver nitrate. The prepared composite based hydrogel exceeds a higher swelling degree than chitosan hydrogels at low pH. The antibacterial activity of the nanocomposite hydrogels was also examined; the results showed that the prepared nanocomposite hydrogels outperformed the pure chitosan hydrogels. This shows them to be a promising material for the biomedical field as a wound dressing and drug release.

Polymer-Based Materials Loaded with Curcumin for Wound Healing Applications

Some of the currently used wound dressings have interesting features such as excellent porosity, good water-absorbing capacity, moderate water vapor transmission rate, high drug loading efficiency, and good capability to provide a moist environment, but they are limited in terms of antimicrobial properties. Their inability to protect the wound from microbial invasion results in wound exposure to microbial infections, resulting in a delayed wound healing process. Furthermore, some wound dressings are loaded with synthetic antibiotics that can cause adverse side effects on the patients. Natural-based compounds exhibit unique features such as good biocompatibility, reduced toxicity, etc. Curcumin, one such natural-based compound, has demonstrated several biological activities such as anticancer, antibacterial and antioxidant properties. Its good antibacterial and antioxidant activity make it beneficial for the treatment of wounds. Several researchers have developed different types of polymer-based wound dressings which were loaded with curcumin. These wound dressings displayed excellent features such as good biocompatibility, induction of skin regeneration, accelerated wound healing processes and excellent antioxidant and antibacterial activity. This review will be focused on the in vitro and in vivo therapeutic outcomes of wound dressings loaded with curcumin.

Medicinal plants used in wound dressings made of electrospun nanofibers

Nanofibers are a type of nanostructures, which due to their unique properties can be used in wound dressing, and electrospinning is a good way to produce them. The benefits of wound dressings made of electrospun nanofibers include a large surface area to volume ratio, high absorption of secretions from the wound, and high air permeability, mimicking the morphology of extracellular matrix (ECM) of the damaged tissue and the possibility of the gradual release of the drug agents loaded on nanofibers. Because of the adaptability of plants to the body, low side effects and the prevalence of antibiotic resistance, interest in using plants is increasing. Combining nanofibers with plants is a way to integrate the physical properties of the structure of nanofibers and the chemical and antibacterial properties of the plants. In recent years, many plants in the forms of extracts, essential oils, and pure active ingredients have been used in the electrospininng and production of nanofiber-containing plants; some of the plants may be a good choice for wound dressings made of electrospun nanofibers.

Repositioning Natural Antioxidants for Therapeutic Applications in Tissue Engineering

Although a large panel of natural antioxidants demonstrate a protective effect in preventing cellular oxidative stress, their low bioavailability limits therapeutic activity at the targeted injury site. The importance to deliver drug or cells into oxidative microenvironments can be realized with the development of biocompatible redox-modulating materials. The incorporation of antioxidant compounds within implanted biomaterials should be able to retain the antioxidant activity, while also allowing graft survival and tissue recovery. This review summarizes the recent literature reporting the combined role of natural antioxidants with biomaterials. Our review highlights how such functionalization is a promising strategy in tissue engineering to improve the engraftment and promote tissue healing or regeneration.

Recent Advances in Nanomaterial-Based Wound-Healing Therapeutics

Nanomaterial-based wound healing has tremendous potential for treating and preventing wound infections with its multiple benefits compared with traditional treatment approaches. In this regard, the physiochemical properties of nanomaterials enable researchers to conduct extensive studies on wound-healing applications. Nonetheless, issues concerning the use of nanomaterials in accelerating the efficacy of existing medical treatments remain unresolved. The present review highlights novel approaches focusing on the recent innovative strategies for wound healing and infection controls based on nanomaterials, including nanoparticles, nanocomposites, and scaffolds, which are elucidated in detail. In addition, the efficacy of nanomaterials as carriers for therapeutic agents associated with wound-healing applications has been addressed. Finally, nanomaterial-based scaffolds and their premise for future studies have been described. We believe that the in-depth analytical review, future insights, and potential challenges described herein will provide researchers an up-to-date reference on the use of nanomedicine and its innovative approaches that can enhance wound-healing applications.

Antibacterial biohybrid nanofibers for wound dressings

Globally, chronic wounds impose a notable burden to patients and healthcare systems. Such skin wounds are readily subjected to bacteria that provoke inflammation and hence challenge the healing process. Furthermore, bacteria induce infection impeding re-epithelialization and collagen synthesis. With an estimated global market of $20.4 billion by 2021, appropriate wound dressing materials e.g. those composed of biopolymers originating from nature, are capable of alleviating the infection incidence and of accelerating the healing process. Particularly, biopolymeric nanofibrous dressings are biocompatible and mostly biodegradable and biomimic the extracellular matrix structure. Such nanofibrous dressings provide a high surface area and the ability to deliver antibiotics and antibacterial agents locally into the wound milieu to control infection. In this regard, with the dangerous evolution of antibiotic resistant bacteria, antibiotic delivery systems are being gradually replaced with antibacterial biohybrid nanofibrous wound dressings. This emerging class of wound dressings comprises biopolymeric nanofibers containing antibacterial nanoparticles, nature-derived compounds and biofunctional agents. Here, the most recent (since 2015) developments of antibacterial biopolymeric nanofibrous wound dressings, particularly those made of biohybrids, are reviewed and their antibacterial efficiency is evaluated based on a comprehensive literature analysis. Lastly, the prospects and challenges are discussed to draw a roadmap for further progresses and to open up future research avenues in this area. STATEMENT OF SIGNIFICANCE: With a global market of $20.4 billion by 2021, skin wound dressings are a crucial segment of the wound care industry. As an advanced class of bioactive wound dressing materials, natural polymeric nanofibers loaded with antibacterial agents, e.g. antimicrobial nanoparticles/ions, nature-derived compounds and biofunctional agents, have shown a remarkable potential for replacement of their classic counterparts. Also, given the expanding concern regarding antibiotic resistant bacteria, such biohybrid nanofibrous wound dressings can outperform classical drug delivery systems. Here, an updated overview of the most recent (since 2015) developments of antibacterial biopolymeric nanofibrous wound dressings is presented. In this review, while discussing about the antibacterial efficiency of such systems, the prospects and challenges are highlighted to draw a roadmap for further progresses in this area.

In situ Fabrication of Nano ZnO/BCM Biocomposite Based on MA Modified Bacterial Cellulose Membrane for Antibacterial and Wound Healing

Background

Developing an ideal wound dressing that meets the multiple demands of safe and practical, good biocompatibility, superior mechanical property and excellent antibacterial activity is highly desirable for wound healing. Bacterial cellulose (BC) is one of such promising class of biopolymers since it can control wound exudates and can provide moist environment to a wound resulting in better wound healing. However, the lack of antibacterial activity has limited its application.

Methods and Results

We prepared a flexible dressing based on a bacterial cellulose membrane and then modified it by chemical crosslinking to prepare in situ synthesis of nZnO/BCM via a facile and eco-friendly approach. Scanning electron microscopy (SEM) results indicated that nZnO/BCM membranes were characterized by an ideal porous structure (pore size: 30~ 90 μm), forming a unique string-beaded morphology. The average water vapor transmission of nZnO/BCM was 2856.60 g/m²/day, which improved the moist environment of nZnO/BCM. ATR-FITR further confirmed the stepwise deposition of nano-zinc oxide. Tensile testing indicated that our nanocomposites were flexible, comfortable and resilient. Bacterial suspension assay and plate counting methods demonstrated that 5wt. % nZnO/BCM possessed excellent antibacterial activity against S.aureus and E. coli, while MTT assay demonstrated that they had no measurable cytotoxicity toward mammalian cells. Moreover, skin irritation test and histocompatibility examination supported that 5wt. % nZnO/BCM had no stimulation to skin and had acceptable biocompatibility with little infiltration of the inflammatory cells. Finally, by using a bacteria-infected (S. aureus and E. coli) murine wound model, we found that nZnO/BCM could prevent in vivo bacterial infections and promote wound healing via accelerating the re-epithelialization and wound contraction, and these membranes had no obvious toxicity toward normal tissues.

Conclusion

Therefore, the constructed nZnO/BCM has great potential for biomedical applications as an efficient antibacterial wound dressing.

Controlled curcumin release from nanofibers based on amphiphilic-block segmented polyurethanes

A series of biodegradable amphiphilic-block segmented polyurethanes (SPUs) are designed and synthesized based on di-block and tri-block macrodiols of polycaprolactone (PCL) and polyethylene glycol (PEG). Curcumin, as a model herbal antibacterial agent, is used due to its effective inhibitory action against Gram-positive and Gram-negative bacteria. Curcumin-loaded nanofibers, with 400-900 nm diameter range, have been prepared by electrospinning of SPUs. The synthesized SPUs can be used for wound dressing applications due to their excellent mechanical properties and higher hydrophilicity in comparison to PCL-based polyurethane. The elongation-at-break of tri-block SPU with PEG-PCL-PEG soft segments is 350% when produced as an electrospun mat and that for film is 1500%. In vitro release of curcumin, examined by UV-Vis spectroscopy, shows a steady release during 18 days. The inclusion of PEG chains in the soft segment increases the hydrophilicity and biodegradation rate of the electrospun mats compared to a PCL-based polyurethane, which eventually results in a higher curcumin release rate. The antibacterial activity of 50 mg of 10% curcumin-loaded SPU nanofibers is about 100% and 93% against Escherichia coli (E. coli ATCC: 25922) and Staphylococcus aureus (S. aureus ATCC: 6538), respectively. Nontoxic behavior of the scaffolds is evaluated through MTT assay against L929 mouse fibroblast cells. The results show that the synthesized SPUs can be used as a nanoscale sustained release carrier. The SPU with PEG-PCL-PEG soft segments is an excellent candidate for wound dressing in tissues undergoing large deformations during normal activities.

Progress in electrospun composite nanofibers: composition, performance and applications for tissue engineering

The discovery of novel methods to fabricate optimal scaffolds that mimic both mechanical and functional properties of the extracellular matrix (ECM) has always been the "holy grail" in tissue engineering. In recent years, electrospinning has emerged as an attractive material fabrication method and has been widely applied in tissue engineering due to its capability of producing non-woven and nanoscale fibers. However, from the perspective of biomimicry, it is difficult for single-component electrospun fiber membranes to achieve the biomimetic purposes of the multi-component extracellular matrix. Based on electrospinning, various functional components can be efficiently and expediently introduced into the membranes, and through the complementation and correlation of the properties of each component, composite materials with comprehensive and superior properties are obtained while maintaining the primitive merits of each component. In this review, we will provide an overview of the attempts made to fabricate electrospinning-based composite tissue engineering materials in the past few decades, which have been divided into organic additives, inorganic additives and organic-inorganic additives.

Nanomaterials for Wound Healing and Infection Control

Wound healing has been intensely studied in order to develop an "ideal" technique that achieves expeditious recovery and reduces scarring to the minimum, thus ensuring function preservation. The classic approach to wound management is represented by topical treatments, such as antibacterial or colloidal agents, in order to prevent infection and promote a proper wound-healing process. Nanotechnology studies submicroscopic particles (maximum diameter of 100 nm), as well as correlated phenomena. Metal nanoparticles (e.g., silver, gold, zinc) are increasingly being used in dermatology, due to their beneficial effect on accelerating wound healing, as well as treating and preventing bacterial infections. Other benefits include: ease of use, less frequent dressing changes and a constantly moist wound environment. This review highlights recent findings regarding nanoparticle application in wound management.

Nanoscaled Biodegradable Metal-Polymeric Three-Dimensional Framework for Endothelial Cell Patterning and Sustained Angiogenesis

The current work describes the development of a nanoscaled biodegradable metal polymeric three-dimensional framework with controlled nanotherapeutic release for endothelial cell patterning and sustained angiogenesis for biomedical applications. Biocompatible polymers gelatin and PLGA were used as polymeric nanofibrous three-dimensional framework in a core-shell manner with the gelatin core containing a biodegradable and bioactive metal nanoframework of cobalt caged with PEGylated curcumin by coaxial electrospinning. FTIR results confirmed the presence of nanobioactives in the core region of a coaxial nanofiber. Scanning electron microscopic analysis of the coaxial nanofibrous system showed a three-dimensional architecture that favored endothelial cell adhesion, patterning, migration, and proliferation. The as-synthesized nanoscaled biodegradable metal polymeric three-dimensional core-shell nanofibers exhibited potent antibacterial efficacy. Further, it improved the endothelial cell patterning promoting angiogenesis. The high therapeutic potential of cobalt nanoframework in the nanofibers enhanced the production of vascular endothelial growth factor promoting angiogenesis that resulted in the earlier restoration of wounded tissue compared with untreated control in vivo animal models. The study opens up a new horizon in exploring biodegradable biosorbable metal nanoframework for biomaterial applications. Additionally, the present study opens up a new strategy in developing biodegradable biosorbable biomaterial with enhanced vascularization efficacy to the biomaterial, which is important for acceptance of these biomaterials into the host tissue.

Aspects of Nanomaterials in Wound Healing

Wound infections impose a remarkable clinical challenge that has a considerable influence on morbidity and mortality of patients, influencing the cost of treatment. The unprecedented advancements in molecular biology have come up with new molecular and cellular targets that can be successfully applied to develop smarter therapeutics against diversified categories of wounds such as acute and chronic wounds. However, nanotechnology-based diagnostics and treatments have achieved a new horizon in the arena of wound care due to its ability to deliver a plethora of therapeutics into the target site, and to target the complexity of the normal wound-healing process, cell type specificity, and plethora of regulating molecules as well as pathophysiology of chronic wounds. The emerging concepts of nanobiomaterials such as nanoparticles, nanoemulsion, nanofibrous scaffolds, graphene-based nanocomposites, etc., and nano-sized biomaterials like peptides/proteins, DNA/RNA, oligosaccharides have a vast application in the arena of wound care. Multi-functional, unique nano-wound care formulations have acquired major attention by facilitating the wound healing process. In this review, emphasis has been given to different types of nanomaterials used in external wound healing (chronic cutaneous wound healing); the concepts of basic mechanisms of wound healing process and the promising strategies that can help in the field of wound management.

A comprehensive review of electrospinning block copolymers

Electrospinning provides a versatile and cost-effective route for the generation of continuous nanofibres with high surface area-to-volume ratio from various polymers. In parallel, block copolymers (BCPs) are promising candidates for many diverse applications, where nanoscale operation is exploited, owing to their intrinsic self-assembling behaviour at these length scales. Judicious combination of BCPs (with their ability to make nanosized domains at equilibrium) and electrospinning (with its ability to create nano- and microsized fibres and particles) allows one to create BCPs with high surface area-to-volume ratio to deliver higher efficiency or efficacy in their given application. Here, we give a comprehensive overview of the wide range of reports on BCP electrospinning with focus placed on the use of molecular design alongside control over specific electrospinning type and post-treatment methodologies to control the properties of the resultant fibrous materials. Particular attention is paid to the applications of these materials, most notably, their use as biomaterials, separation membranes, sensors, and electronic materials.

Curcumin in tissue engineering: A traditional remedy for modern medicine

Curcumin is the principal polyphenolic compound present in turmeric with broad applications in tissue engineering and regenerative medicine. It has some important inherent properties with the potential to facilitate tissue healing, including anti-inflammatory, anti-oxidant, and antibacterial activities. Therefore, curcumin has been used for the treatment of various damaged tissues, especially wound injuries. There are different forms of curcumin, among which nano-formulations are of a great importance in regenerative medicine. It is also important to design sophisticated delivery systems for controlled/localized delivery of curcumin to the target tissues and organs. Although there are many reports on the advantages of this compound, further research is required to fully explore its clinical usage. The review describes the physicochemical and biological properties of curcumin and the current state of the evidence on its applications in tissue engineering. © 2018 BioFactors, 45(2):135-151, 2019.

Nano-silver-incorporated biomimetic polydopamine coating on a thermoplastic polyurethane porous nanocomposite as an efficient antibacterial wound dressing

Background

Developing an ideal wound dressing that meets the multiple demands of good biocompatibility, an appropriate porous structure, superior mechanical property and excellent antibacterial activity against drug-resistant bacteria is highly desirable for clinical wound care. Biocompatible thermoplastic polyurethane (TPU) membranes are promising candidates as a scaffold; however, their lack of a suitable porous structure and antibacterial activity has limited their application. Antibiotics are generally used for preventing bacterial infections, but the global emergence of drug-resistant bacteria continues to cause social concerns.

Results

Consequently, we prepared a flexible dressing based on a TPU membrane with a specific porous structure and then modified it with a biomimetic polydopamine coating to prepare in situ a nano-silver (NS)-based composite via a facile and eco-friendly approach. SEM images showed that the TPU/NS membranes were characterized by an ideal porous structure (pore size: ~ 85 μm, porosity: ~ 65%) that was decorated with nano-silver particles. ATR-FITR and XRD spectroscopy further confirmed the stepwise deposition of polydopamine and nano-silver. Water contact angle measurement indicated improved surface hydrophilicity after coating with polydopamine. Tensile testing demonstrated that the TPU/NS membranes had an acceptable mechanical strength and excellent flexibility. Subsequently, bacterial suspension assay, plate counting methods and Live/Dead staining assays demonstrated that the optimized TPU/NS2.5 membranes possessed excellent antibacterial activity against P. aeruginosa, E. coli, S. aureus and MRSA bacteria, while CCK8 testing, SEM observations and cell apoptosis assays demonstrated that they had no measurable cytotoxicity toward mammalian cells. Moreover, a steady and safe silver-releasing profile recorded by ICP-MS confirmed these results. Finally, by using a bacteria-infected (MRSA or P. aeruginosa) murine wound model, we found that TPU/NS2.5 membranes could prevent in vivo bacterial infections and promote wound healing via accelerating the re-epithelialization process, and these membranes had no obvious toxicity toward normal tissues.

Conclusion

Based on these results, the TPU/NS2.5 nanocomposite has great potential for the management of wounds, particularly for wounds caused by drug-resistant bacteria.

Janus N,N-dimethylformamide as a solvent for a gradient porous wound dressing of poly(vinylidene fluoride) and as a reducer for in situ nano-silver production: anti-permeation, antibacterial and antifouling activities against multi-drug-resistant bacteria both in vitro and in vivo

The requirements for anti-permeation, anti-infection and antifouling when treating a malicious wound bed raise new challenges for wound dressing. The present study used N,N-dimethylformamide to treat poly(vinylidene fluoride) (PVDF) in order to obtain a dressing impregnated with in situ generated nano-silver particles (NS) via an immersion phase inversion method. Scanning electron microscopy (SEM) images showed that the film was characterized by a two-layer asymmetric structure with different pore sizes (top layer: ∼0.4 μm; bottom layer: ∼1.8 μm). The moisture permeability test indicated that the film had an optimal water vapor transmission rate (WVTR: ∼2500 g m-2 per day). TEM images revealed the successful formation of spherical NS, and Fourier-transform infrared spectroscopy (FTIR) demonstrated the integration of PVDF and NS (i.e., PVDF/NS). Correspondingly, the water contact angle measurements confirmed increased membrane surface hydrophobicity after NS integration. The inductively coupled plasma (ICP) spectrometry showed that the PVDF/NS displayed a continuous and safe release of silver ions. Moreover, in vitro experiments indicated that PVDF/NS films possessed satisfactory anti-permeation, antibacterial and antifouling activities against A. baumannii and E. coli bacteria, while they exhibited no obvious cytotoxicity toward mammalian HaCaT cells. Finally, the in vivo results showed that the nanoporous top layer of film could serve as a physical barrier to prevent bacterial penetration, whereas the microporous bottom layer could efficiently prevent bacterial infection caused by biofouling, leading to fast re-epithelialization via the enhancement of keratinocyte proliferation. Collectively, the results show that the PVDF/NS25 film has a promising application in wound treatment, especially for wounds infected by multi-drug-resistant bacteria such as A. baumannii.

Fabrication of curcumin-loaded electrospun nanofiberous polyurethanes with anti-bacterial activity

Abstract

Two series of polyurethane (PU), based on polycaprolactone (PCL) as soft segments with two different molecular weights (2000 and 530 Da), and hexamethylene diisocyanate (HDI) and 1,4-butandiol (BDO) as hard segments were synthesized to fabricate curcumin-loaded electrospun nanofibrous PCL-based PU substrate. Chemical structures of the synthesized PUs were characterized by FTIR and NMR spectroscopy techniques. The thermal properties were analyzed by differential scanning calorimetry (DSC) and surface hydrophilicity was studied by static contact angle and bulk hydrophilicity was evaluated by water uptake test. Thereafter, bead-free PU nanofiberous substrate containing curcumin was fabricated by electrospinning and morphology of the mats was observed by scanning electron microscopy (SEM). Mechanical properties of the electrospun mats in comparison with polymeric films were assessed by a universal test machine. The in vitro release of curcumin was studied by UV–Vis spectroscopy. The optical density of the bacterial solutions was used to evaluate the antibacterial activity of the curcumin-loaded nanofibrous mats against Escherichia coli (E-coli ATCC: 25922). The results showed that curcumin-loaded PU synthesized by PCL with molecular weight of 2000 Da displayed better mechanical properties as well as better antibacterial properties in wound dressing application.

Graphical abstract

Thermosensitive hydrogels a versatile concept adapted to vaginal drug delivery

Vaginal drug delivery represents an attractive strategy for local and systemic delivery of drugs otherwise poorly absorbed after oral administration. The rather dense vascular network, mucus permeability and the physiological phenomenon of the uterine first-pass effect can all be exploited for therapeutic benefit. However, several physiological factors such as an acidic pH, constant secretion, and turnover of mucus as well as varying thickness of the vaginal epithelium can impact sustained drug delivery. In recent years, polymers have been designed to tackle challenges mentioned above. In particular, thermosensitive hydrogels hold great promise due to their stability, biocompatibility, adhesion properties and adjustable drug release kinetics. Here, we discuss the physiological and anatomical uniqueness of the vaginal environment and how it impacts the safe and efficient vaginal delivery and also reviewed several thermosensitive hydrogels deemed suitable for vaginal drug delivery by addressing specific characteristics, which are essential to engage the vaginal environment successfully.

Danggui Buxue Extract-Loaded Liposomes in Thermosensitive Gel Enhance In Vivo Dermal Wound Healing via Activation of the VEGF/PI3K/Akt and TGF-β/Smads Signaling Pathway

Danggui Buxue extract-loaded liposomes in thermosensitive gel (DBLTG) are a sustained-release local drug delivery system derived from Danggui Buxue decoction, a well-known Chinese herb formula with wound healing potential. In the present study, we investigated the therapeutic effects of DBLTG on dorsal full-thickness excisional wounds in rats by measuring the percentage of wound contraction and hydroxyproline content, as well as conducting histological observations and immunohistochemical analysis. We also assessed involvement of the vascular endothelial growth factor (VEGF)/phosphatidylinositol 3-kinase (PI3K)/Akt and transforming growth factor beta (TGF-β)/Smads signaling pathways in the wound healing process upon DBLTG treatment via western blot. The results show that DBLTG treatment remarkably accelerates wound closure, enhances hydroxyproline content in wound granulation tissue, promotes cutaneous wound healing by reducing the inflammatory response and improving fresh granulation tissue formation, and significantly increases the density of blood vessels, cells proliferation, and expression of type I and type III collagen. Moreover, DBLTG markedly upregulates the relative protein expression of VEGFA and TGF-β1 and notably stimulates the phosphorylation of Akt and Smad2/3. In conclusion, DBLTG significantly improved dermal wound healing in rats by stimulating angiogenesis and collagen synthesis; these effects are likely mediated via the VEGF/PI3K/Akt and TGF-β/Smads signaling pathways, respectively.

Optimization and integration of nanosilver on polycaprolactone nanofibrous mesh for bacterial inhibition and wound healing in vitro and in vivo

Bacterial infection is a major hurdle to wound healing, and the overuse of antibiotics have led to global issue, such as emergence of multidrug-resistant bacteria, even "super bacteria". On the contrary, nanosilver (NS) can kill bacteria without causing resistant bacterial strains. In this study, NS was simply generated in situ on the polycaprolactone (PCL) nanofibrous mesh using an environmentally benign and mussel-inspired dopamine (DA). Scanning electron microscopy showed that NS uniformly formed on the nanofibers of PCL mesh. Fourier transform infrared spectroscopy revealed the step-by-step preparation of pristine PCL mesh, including DA coating and NS formation, which were further verified by water contact angle changing from hydrophobic to hydrophilic. To optimize the NS dose, the antibacterial activity of PCL/NS against Staphylococcus aureus, Escherichia coli and Acinetobacter baumannii was detected by bacterial suspension assay, and the cytotoxicity of NS was evaluated using cellular morphology observation and Cell Counting Kit-8 (CCK8) assay. Then, inductively coupled plasma atomic emission spectrometry exhibited that the optimized PCL/NS had a safe and sustained silver release. Moreover, PCL/NS could effectively inhibit bacterial infection in an infectious murine full-thickness skin wound model. As demonstrated by the enhanced level of proliferating cell nuclear antigen (PCNA) in keratinocytes and longer length of neo-formed epidermis, PCL/NS accelerated wound healing by promoting re-epithelialization via enhancing keratinocyte proliferation in infectious wounds.

Functional electrospun fibers for the treatment of human skin wounds

Wounds are trauma induced defects of the human skin involving a multitude of endogenous biochemical events and cellular reactions of the immune system. The healing process is extremely complex and affected by the patient's physiological conditions, potential implications like infectious pathogens and inflammation as well as external factors. Due to increasing incidence of chronic wounds and proceeding resistance of infection pathogens, there is a strong need for effective therapeutic wound care. In this context, electrospun fibers with diameters in the nano- to micrometer range gain increasing interest. While resembling the structure of the native human extracellular matrix, such fiber mats provide physical and mechanical protection (including protection against bacterial invasion). At the same time, the fibers allow for gas exchange and prevent occlusion of the wound bed, thus facilitating wound healing. In addition, drugs can be incorporated within such fiber mats and their release can be adjusted by the material and dimensions of the individual fibers. The review gives a comprehensive overview about the current state of electrospun fibers for therapeutic application on skin wounds. Different materials as well as fabrication techniques are introduced including approaches for incorporation of drugs into or drug attachment onto the fiber surface. Against the background of wound pathophysiology and established therapy approaches, the therapeutic potential of electrospun fiber systems is discussed. A specific focus is set on interactions of fibers with skin cells/tissues as well as wound pathogens and strategies to modify and control them as key aspects for developing effective wound therapeutics. Further, advantages and limitations of controlled drug delivery from fiber mats to skin wounds are discussed and a future perspective is provided.

Nano cellulose dispersed chitosan film with Ag NPs/Curcumin: An in vivo study on Albino Rats for wound dressing

With an aim to develop chitosan film with controllable swelling behavior and maximum antimicrobial efficacy, we hereby report cellulose nano crystals loaded chitosan films with Curcumin/Ag nano particles embedded as strong antimicrobial agents. The CNC had average size of 40-90nm with poly dispersity index of 3.641. The TEM analysis of Ag NPs, produced via DMF reduction, revealed a particle size range of 15-25nm. The Surface Plasmon resonance (SPR) of these Ag NPs shifted from 380 to 440nm, with the increase in concentration of Ag (I). The TGA of the film samples Ch/CNC, and Ch/CNC (Ag₄₆₃/Cur₄₅₀) exhibited% weight loss of around 95 and 80 respectively, thus indicating higher stability due to presence of Ag NPs. In XRD analysis 2θ reflections at 38.12, 44.28 and 66.46°^, confirmed the presence planes (1 1), (2 0) and (2 0) respectively. In skin irritation test, the mean Erythema scores observed after 72h was zero for both the Curcumin and Ag NPs/Curcumin loaded films. The percent wound reduction, observed for the film samples Ch/CNC (Cur₄₅₀) and Ch/CNC (Ag NP₄₆₃/Cur₄₅₀) was 57.8 and 97.2 respectively, indicating better suitability of Ag NPs/Curcumin loaded film.

Investigating the use of curcumin-loaded electrospun filaments for soft tissue repair applications

Electrospun filaments represent a new generation of medical textiles with promising applications in soft tissue repair. A potential strategy to improve their design is to combine them with bioactive molecules. Curcumin, a natural compound found in turmeric, is particularly attractive for its antioxidant, anti-inflammatory, and antimicrobial properties. However, investigating the range of relevant doses of curcumin in materials designed for tissue regeneration has remained limited. In this paper, a wide range of curcumin concentrations was explored and the potential of the resulting materials for soft tissue repair applications was assessed. Polydioxanone (PDO) filaments were prepared with various amounts of curcumin: 0%, 0.001%, 0.01%, 0.1%, 1%, and 10% (weight to weight ratio). The results from the present study showed that, at low doses (≤0.1%), the addition of curcumin has no influence on the spinning process or on the physicochemical properties of the filaments, whereas higher doses lead to smaller fiber diameters and improved mechanical properties. Moreover, filaments with 0.001% and 0.01% curcumin stimulate the metabolic activity and proliferation of normal human dermal fibroblasts (NHDFs) compared with the no-filament control. However, this stimulation is not significant when compared to the control filaments (0%). Highly dosed filaments induce either the inhibition of proliferation (with 1%) or cell apoptosis (with 10%) as a result of the concentrations of curcumin found in the medium (9 and 32 μM, respectively), which are near or above the known toxicity threshold of curcumin (~10 μM). Moreover, filaments with 10% curcumin increase the catalase activity and glutathione content in NHDFs, indicating an increased production of reactive oxygen species resulting from the large concentration of curcumin. Overall, this study suggested that PDO electrospun filaments loaded with low amounts of curcumin are more promising compared with higher concentrations for stimulating tissue repair. This study also highlighted the need to explore lower concentrations when using polymers as PDO, such as those with polycaprolactone and other degradable polyesters.

The Feasibility of a Handheld Electrospinning Device for the Application of Nanofibrous Wound Dressings

Objectives: The aim of this study was to determine the feasibility of a portable electrospinning device for the application of wound dressings. Approach: Four polymer nanofibers dressings were applied on superficial partial thickness wounds to a porcine model and compared with a traditional paraffin tulle gras dressing. The polymer nanofibrous dressings were applied using a handheld portable electrospinning device activated at a short distance from the wound. The partial thickness donor sites were evaluated on day 2, 7, and 14 when dressings were removed and tissue samples were taken for histological examination. Results: No significant difference was detected between the different electrospun nanofibrous dressings and traditional paraffin tulle gras. Desirable characteristics of the electrospun nanofiber dressing group included nontouch technique, ease of application, adherence and reduction in wound edema and inflammation. There was no delayed wound healing or signs of infection reported in both the electrospun nanofiber and traditional tulle gras dressings. Innovation: Used on partial thickness wounds, polymer electrospun nanofiber dressings provide excellent surface topography and are a nontouch, feasible, and safe method to promote wound healing with the potential to reduce wound infections. Such custom-made nanofibrous dressings have implications for the reduction of pain and trauma, number of dressing changes, scarring, and an added cost benefit. Conclusion: We have demonstrated that this portable handheld electrospinning device can be utilized for different formulations and materials and customized according to the characteristics of the target wound at the various stages of wound healing.

Electrospun Nanofibres Containing Antimicrobial Plant Extracts

Over the last 10 years great research interest has been directed toward nanofibrous architectures produced by electrospinning bioactive plant extracts. The resulting structures possess antimicrobial, anti-inflammatory, and anti-oxidant activity, which are attractive for biomedical applications and food industry. This review describes the diverse approaches that have been developed to produce electrospun nanofibres that are able to deliver naturally-derived chemical compounds in a controlled way and to prevent their degradation. The efficacy of those composite nanofibres as wound dressings, scaffolds for tissue engineering, and active food packaging systems will be discussed.

Graphene oxide-modified electrospun polyvinyl alcohol nanofibrous scaffolds with potential as skin wound dressings

Graphene oxide-modified electrospun polyvinyl alcohol nanofibrous scaffolds exhibit good biocompatibility and have potential application in skin tissue engineering.