Chitosan-based GOx@Co-MOF composite hydrogel: A promising strategy for enhanced antibacterial and wound healing effects

A novel composite hydrogel was synthesized via Schiff base reaction between chitosan and di-functional poly(ethylene glycol) (DF-PEG), incorporating glucose oxidase (GOx) and cobalt metal-organic frameworks (Co-MOF). The resulting CS/PEG/GOx@Co-MOF composite hydrogel was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectroscopy (EDS). The results confirmed successful integration and uniform distribution of Co-MOF within the hydrogel matrix. Functionally, the hydrogel exploits the catalytic decomposition of glucose by GOx to generate gluconic acid and hydrogen peroxide (H2O2), while Co-MOF gradually releases metal ions and protects GOx. This synergy enhanced the antibacterial activity of the composite hydrogel against both Gram-positive (S. aureus) and Gram-negative bacteria (E. coli), outperforming conventional chitosan-based hydrogels. The potential of the composite hydrogel in treating wound infections was evaluated through antibacterial and wound healing experiments. Overall, CS/PEG/GOx@Co-MOF hydrogel holds great promise for the treatment of wound infections, paving the way for further research and potential clinical applications.

Dual-Modified Hyaluronic Acid for Tunable Double Cross-Linked Hydrogel Adhesives

Conventional techniques for the closure of wounds, such as sutures and staples, have significant drawbacks that can negatively impact wound healing. Tissue adhesives have emerged as promising alternatives, but poor adhesion, low mechanical properties, and toxicity have hindered their widespread clinical adoption. In this work, a dual modified, aldehyde and methacrylate hyaluronic acid (HA) biopolymer (HA-MA-CHO) has been synthesized through a simplified route for use as a double cross-linked network (DCN) hydrogel (HA-MA-CHO-DCN) adhesive for the effective closure and sealing of wounds. HA-MA-CHO-DCN cross-links in two stages: initial cross-linking of the aldehyde functionality (CHO) of HA-MA-CHO using a disulfide-containing cross-linker, 3,3'-dithiobis (propionic hydrazide) (DTPH), leading to the formation of a self-healing injectable gel, followed by further cross-linking via ultraviolet (UV) initiated polymerization of the methacrylate (MA) functionality. This hydrogel adhesive shows a stable swelling behavior and remarkable versatility as the storage modulus (G') has shown to be highly tunable (103-105 Pa) for application to many different wound environments. The new HA-MA-CHO-DCN hydrogel showed excellent adhesive properties by surpassing the burst pressure and lap-shear strength for the widely used bovine serum albumin-glutaraldehyde (BSAG) glue while maintaining excellent cell viability.

Electrospun organic/inorganic hybrid nanofibers for accelerating wound healing: a review

Electrospun nanofiber membranes hold great promise as scaffolds for tissue reconstruction, mirroring the natural extracellular matrix (ECM) in their structure. However, their limited bioactive functions have hindered their effectiveness in fostering wound healing. Inorganic nanoparticles possess commendable biocompatibility, which can expedite wound healing; nevertheless, deploying them in the particle form presents challenges associated with removal or collection. To capitalize on the strengths of both components, electrospun organic/inorganic hybrid nanofibers (HNFs) have emerged as a groundbreaking solution for accelerating wound healing and maintaining stability throughout the healing process. In this review, we provide an overview of recent advancements in the utilization of HNFs for wound treatment. The review begins by elucidating various fabrication methods for hybrid nanofibers, encompassing direct electrospinning, coaxial electrospinning, and electrospinning with subsequent loading. These techniques facilitate the construction of micro-nano structures and the controlled release of inorganic ions. Subsequently, we delve into the manifold applications of HNFs in promoting the wound regeneration process. These applications encompass hemostasis, antibacterial properties, anti-inflammatory effects, stimulation of cell proliferation, and facilitation of angiogenesis. Finally, we offer insights into the prospective trends in the utilization of hybrid nanofiber-based wound dressings, charting the path forward in this dynamic field of research.

Multifunctional bilayer membranes composed of poly(lactic acid), beta-chitin whiskers and silver nanoparticles for wound dressing applications

Nanomaterial-based wound dressings have been extensively studied for the treatment of both minor and life-threatening tissue injuries. These wound dressings must possess several crucial characteristics, such as tissue compatibility, non-toxicity, appropriate biodegradability to facilitate wound healing, effective antibacterial activity to prevent infection, and adequate physical and mechanical strength to withstand repetitive dynamic forces that could potentially disrupt the healing process. Nevertheless, the development of nanostructured wound dressings that incorporate various functional micro- and nanomaterials in distinct architectures, each serving specific purposes, presents significant challenges. In this study, we successfully developed a novel multifunctional wound dressing based on poly(lactic acid) (PLA) fibrous membranes produced by solution-blow spinning (SBS) and electrospinning. The PLA-based membranes underwent surface modifications aimed at tailoring their properties for utilization as effective wound dressing platforms. Initially, beta-chitin whiskers were deposited onto the membrane surface through filtration, imparting hydrophilic character. Afterward, silver nanoparticles (AgNPs) were incorporated onto the beta-chitin layer using a spray deposition method, resulting in platforms with antimicrobial properties against both Staphylococcus aureus and Escherichia coli. Cytotoxicity studies demonstrated the biocompatibility of the membranes with the neonatal human dermal fibroblast (HDFn) cell line. Moreover, bilayer membranes exhibited a high surface area and porosity (> 80%), remarkable stability in aqueous media, and favorable mechanical properties, making them promising candidates for application as multifunctional wound dressings.

Smart and versatile biomaterials for cutaneous wound healing

The global increase of cutaneous wounds imposes huge health and financial burdens on patients and society. Despite improved wound healing outcomes, conventional wound dressings are far from ideal, owing to the complex healing process. Smart wound dressings, which are sensitive to or interact with changes in wound condition or environment, have been proposed as appealing therapeutic platforms to effectively facilitate wound healing. In this review, the wound healing processes and features of existing biomaterials are firstly introduced, followed by summarizing the mechanisms of smart responsive materials. Afterwards, recent advances and designs in smart and versatile materials of extensive applications for cutaneous wound healing were submarined. Finally, clinical progresses, challenges and future perspectives of the smart wound dressing are discussed. Overall, by mapping the composition and intrinsic structure of smart responsive materials to their individual needs of cutaneous wounds, with particular attention to the responsive mechanisms, this review is promising to advance further progress in designing smart responsive materials for wounds and drive clinical translation.

Animal tissue-derived biomaterials for promoting wound healing

The skin serves as the primary barrier between the human body and external environment, and is therefore susceptible to damage from various factors. In response to this challenge, animal tissue-derived biomaterials have emerged as promising candidates for wound healing due to their abundant sources, low side-effect profiles, exceptional bioactivity, biocompatibility, and unique extracellular matrix (ECM) mimicry. The evolution of modern engineering technology and therapies has allowed these animal tissue-derived biomaterials to be transformed into various forms and modified to possess the necessary properties for wound repair. This review provides an overview of the wound healing process and the factors that influence it. We then describe the extraction methods, important properties, and recent practical applications of various animal tissue-derived biomaterials. Our focus then shifts to the critical properties of these biomaterials in skin wound healing and their latest research developments. Finally, we critically examine the limitations and future prospects of biomaterials generated from animal tissues in this field.

Functionalised-biomatrix for wound healing and cutaneous regeneration: future impactful medical products in clinical translation and precision medicine

Skin tissue engineering possesses great promise in providing successful wound injury and tissue loss treatments that current methods cannot treat or achieve a satisfactory clinical outcome. A major field direction is exploring bioscaffolds with multifunctional properties to enhance biological performance and expedite complex skin tissue regeneration. Multifunctional bioscaffolds are three-dimensional (3D) constructs manufactured from natural and synthetic biomaterials using cutting-edge tissue fabrication techniques incorporated with cells, growth factors, secretomes, antibacterial compounds, and bioactive molecules. It offers a physical, chemical, and biological environment with a biomimetic framework to direct cells toward higher-order tissue regeneration during wound healing. Multifunctional bioscaffolds are a promising possibility for skin regeneration because of the variety of structures they provide and the capacity to customise the chemistry of their surfaces, which allows for the regulated distribution of bioactive chemicals or cells. Meanwhile, the current gap is through advanced fabrication techniques such as computational designing, electrospinning, and 3D bioprinting to fabricate multifunctional scaffolds with long-term safety. This review stipulates the wound healing processes used by commercially available engineered skin replacements (ESS), highlighting the demand for a multifunctional, and next-generation ESS replacement as the goals and significance study in tissue engineering and regenerative medicine (TERM). This work also scrutinise the use of multifunctional bioscaffolds in wound healing applications, demonstrating successful biological performance in the in vitro and in vivo animal models. Further, we also provided a comprehensive review in requiring new viewpoints and technological innovations for the clinical application of multifunctional bioscaffolds for wound healing that have been found in the literature in the last 5 years.

Drug Delivery Systems in Regenerative Medicine: An Updated Review

Modern drug discovery methods led to evolving new agents with significant therapeutic potential. However, their properties, such as solubility and administration-related challenges, may hinder their benefits. Moreover, advances in biotechnology resulted in the development of a new generation of molecules with a short half-life that necessitates frequent administration. In this context, controlled release systems are required to enhance treatment efficacy and improve patient compliance. Innovative drug delivery systems are promising tools that protect therapeutic proteins and peptides against proteolytic degradation where controlled delivery is achievable. The present review provides an overview of different approaches used for drug delivery.

Hybrid Systems of Nanofibers and Polymeric Nanoparticles for Biological Application and Delivery Systems

Nanomedicine is a new discipline resulting from the combination of nanotechnology and biomedicine. Nanomedicine has contributed to the development of new and improved treatments, diagnoses, and therapies. In this field, nanoparticles have notable importance due to their unique properties and characteristics, which are useful in different applications, including tissue engineering, biomarkers, and drug delivery systems. Electrospinning is a versatile technique used to produce fibrous mats. The high surface area of the electrospun mats makes them suitable for applications in fields using nanoparticles. Electrospun mats are used for tissue engineering, wound dressing, water-treatment filters, biosensors, nanocomposites, medical implants, protective clothing materials, cosmetics, and drug delivery systems. The combination of nanoparticles with nanofibers creates hybrid systems that acquire properties that differ from their components' characteristics. By utilizing nanoparticles and nanofibers composed of dissimilar polymers, the two synergize to improve the overall performance of electrospinning mats and nanoparticles. This review summarizes the hybrid systems of polymeric nanoparticles and polymeric nanofibers, critically analyzing how the combination improves the properties of the materials and contributes to the reduction of some disadvantages found in nanometric devices and systems.

Polymeric Gel Scaffolds and Biomimetic Environments for Wound Healing

Infected wounds that do not heal are a worldwide problem that is worsening, with more people dying and more money being spent on care. For any disease to be managed effectively, its root cause must be addressed. Effective wound care becomes a bigger problem when various traditional wound healing methods and products may not only fail to promote good healing. Still, it may also hinder the healing process, causing wounds to stay open longer. Progress in tissue regeneration has led to developing three-dimensional scaffolds (3D) or constructs that can be leveraged to facilitate cell growth and regeneration while preventing infection and accelerating wound healing. Tissue regeneration uses natural and fabricated biomaterials that encourage the growth of tissues or organs. Even though the clinical need is urgent, the demand for polymer-based therapeutic techniques for skin tissue abnormalities has grown quickly. Hydrogel scaffolds have become one of the most imperative 3D cross-linked scaffolds for tissue regeneration because they can hold water perfectly and are porous, biocompatible, biodegradable, and biomimetic. For damaged organs or tissues to heal well, the porosity topography of the natural extracellular matrix (ECM) should be imitated. This review details the scaffolds that heal wounds and helps skin tissue to develop. After a brief overview of the bioactive and drug-loaded polymeric hydrogels, the discussion moves on to how the scaffolds are made and what they are made of. It highlights the present uses of in vitro and in-vivo employed biomimetic scaffolds. The prospects of how well bioactiveloaded hydrogels heal wounds and how nanotechnology assists in healing and regeneration have been discussed.

A New Mediterranean Flour Moth-Derived Chitosan: Characterization and Co-electrospun Hybrid Fabrication

In this study, the chitin of adult Mediterranean flour moth (Ephestia kuheniella) (Cht) was extracted and then converted to chitosan by deacetylation process to achieve the chitosan derived from E. kuheniella (Chs_fm). The new chitosan-based scaffold was produced using the polyvinyl alcohol (PVA) co-electrospinning technique. The degree of deacetylation was obtained using the distillation-titration and Fourier transform infrared spectroscopy. The surface morphology and crystallinity index of Chs_fm were observed using scanning electron microscopy and X-ray diffraction analysis, respectively, and compared with the commercial chitosan (Chs_c). Thermogravimetric analysis was used to estimate two chitosans' water content and thermal stability. The average molecular mass analysis was performed using viscometry. Moreover, the minimum inhibitory concentration and DPPH assay were used to study the antimicrobial activity and antioxidant potential of the Chs_fm, respectively. Accordingly, Chs_fm was smoother with fewer pores and flakes than Chs_c, and its crystallinity index was higher than Chs_c. The water content and thermal stability were lower and similar for Chs_fm compared to Chs_c. The average molecular mass of Chs_fm was ~ 5.8 kDa, making it classified as low molecular weight chitosan. The antimicrobial activity of Chs_fm against a representative Gram-negative bacteria; E. coli resulted to be the same as Chs_c. However, less effective than Chs_c against a representative Gram-positive bacteria is S. aureus. The Chs_fm/PVA ratio scaffold was optimized at 30:70 to fabricate a uniform nanofiber scaffold.

Porous yet dense matrices: using ice to shape collagen 3D cell culture systems with increased physiological relevance

Standard in vitro cell cultures are one of the pillars of biomedical sciences. However, there is increasing evidence that 2D systems provide biological responses that are often in disagreement with in vivo observations, partially due to limitations in reproducing the native cellular microenvironment. 3D materials that are able to mimic the native cellular microenvironment to a greater extent tackle these limitations. Here, we report Porous yet Dense (PyD) type I collagen materials obtained by ice-templating followed by topotactic fibrillogenesis. These materials combine extensive macroporosity, favouring the cell migration and nutrient exchange, as well as dense collagen walls, which mimic locally the extracellular matrix. When seeded with Normal Human Dermal Fibroblasts (NHDFs), PyD matrices allow for faster and more extensive colonisation when compared with equivalent non-porous matrices. The textural properties of the PyD materials also impact cytoskeletal and nuclear 3D morphometric parameters. Due to the effectiveness in creating a biomimetic 3D environment for NHDFs and the ability to promote cell culture for more than 28 days without subculture, we anticipate that PyD materials could configure an important step towards in vitro systems applicable to other cell types and with higher physiological relevance.

Electrospun kaolin-loaded chitosan/PEO nanofibers for rapid hemostasis and accelerated wound healing

Development of chitosan-based hemostatic products and their application in wound healing has always been a research hotspot in the field of emergency treatment and biomedicine. In this study, the classic hemostatic chitosan and the most well-known inorganic hemostatic agent-kaolin were tried to combine to form a more excellent dressing. Together with the aid of non-toxic, harmless and good hydrophilic polyethylene oxide, chitosan/polyethylene oxide (PEO)/kaolin nanofiber membranes (CPKs) were prepared by electrospinning technology. Such membranes exhibited adjustable mechanical properties and good biocompatibility. Furthermore, a series of in vitro coagulation experiments proved that CPKs with 10 % ratio of kaolin (CPK10) has excellent hemostatic ability. Especially, in the whole blood coagulation time (WBCT) assay, the hemostatic time of CPK10 (43 ± 1.4 s) was significantly lower than that of chitosan/polyethylene oxide (CPK0) nanofiber membrane (61 ± 2.2 s) and QuikClot® Combat Gauze (55.7 ± 1.2 s). The further rat liver injury test reconfirmed that CPK10 can stop bleeding better and faster compared to other groups. In addition, CPKs could promote back wound healing in rats within 14 days without significant inflammatory response. This safe and effective hemostatic CPKs is expected to be a promising candidate hemostat in pre-hospital medical care.

Commercial wound dressings for the treatment of exuding wounds: an in-depth physico-chemical comparative study

Background

Nowadays, a wide range of wound dressings is already commercially available. The selection of the dressing is of paramount importance as inappropriate wound management and dressing selection can delay the wound healing process. Not only can this be distressing for the patient, but it can also contribute to complications such as maceration and subsequent infection. Many researchers are targeting the design of dressings with superior properties over existing commercial dressings. However, reported results in the state-of-the-art are rarely benchmarked against commercial dressings. The aim of this study was to determine several characteristics of a large variety of the most frequently used commercial wound dressings, providing an overview for both practitioners and researchers.

Methods

For this comparative study, 11 frequently used commercial wound dressings were selected, representing the different types. The morphology was studied using scanning electron microscopy. The dressings were characterized in terms of swelling capacity (water, phosphate buffered saline and simulated wound fluid), moisture vapour transmission rate (MVTR) and moisture uptake capacity (via dynamic vapour sorption) as well as mechanical properties using tensile testing and texturometry.

Results

The selected dressings showed distinctive morphological differences (fibrous, porous and/or gel) which was reflected in the different properties. Indeed, the swelling capacities ranged between 1.5 and 23.2 g/g (water), 2.1 and 17.6 g/g (phosphate buffered saline) or 2.9 and 20.8 g/g (simulated wound fluid). The swelling capacity of the dressings in water increased even further upon freeze-drying, due to the formation of pores. The MVTR values varied between 40 and 930 g/m²/24 h. The maximal moisture uptake capacity varied between 5.8% and 105.7% at 95% relative humidity. Some commercial dressings exhibited a superior mechanical strength, due to either being hydrophobic or multi-layered.

Conclusions

The present work not only offers insight into a valuable toolbox of suitable wound dressing characterization techniques, but also provides an extensive landscaping of commercial dressings along with their physico-chemical properties, obtained through reproducible experimental protocols. Furthermore, it ensures appropriate benchmark values for commercial dressings in all forthcoming studies and could aid researchers with the development of novel modern wound dressings. The tested dressings either exhibited a high strength or a high swelling capacity, suggesting that there is still a strong potential in the wound dressings market for dressings that possess both.

Core-shell alum-borneol fiber for high bioavailability

Currently, the treatment of burns poses a significant challenge to clinical surgical. The use of nanofibers combined with drugs provides an entirely new option for treating burns. Alum-borneol combination has been shown as a promising alternative in clinical burn treatment. However, the utilization of the alum-borneol combination is not optimistic due to the low solubility of borneol. In this study, alum-borneol incorporated polyvinyl pyrrolidone fibers with a core-shell structure were fabricated through coaxial electrospinning. In vitro Borneol release behavior of fibers with different ratios of alum to borneol was explored. Scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimeter, in vitro drug release, and in vitro release mechanism were evaluated. The results showed that the fiber membranes maintained an integrated morphology. In vitro dissolution data showed an improved solubility of borneol, which reached more than 82% at 240 min in alum-borneol fibers. It was 4.8 times higher than borneol powder, and the ratio of alum to borneol was 2:1 for the best results. Therefore, alum-borneol incorporated polyvinyl pyrrolidone fibers can significantly improve the dissolution rate of borneol, which opens up a new way for the combined application of the alum and borneol.

Advances in Electrospun Hybrid Nanofibers for Biomedical Applications

Electrospun hybrid nanofibers, based on functional agents immobilized in polymeric matrix, possess a unique combination of collective properties. These are beneficial for a wide range of applications, which include theranostics, filtration, catalysis, and tissue engineering, among others. The combination of functional agents in a nanofiber matrix offer accessibility to multifunctional nanocompartments with significantly improved mechanical, electrical, and chemical properties, along with better biocompatibility and biodegradability. This review summarizes recent work performed for the fabrication, characterization, and optimization of different hybrid nanofibers containing varieties of functional agents, such as laser ablated inorganic nanoparticles (NPs), which include, for instance, gold nanoparticles (Au NPs) and titanium nitride nanoparticles (TiNPs), perovskites, drugs, growth factors, and smart, inorganic polymers. Biocompatible and biodegradable polymers such as chitosan, cellulose, and polycaprolactone are very promising macromolecules as a nanofiber matrix for immobilizing such functional agents. The assimilation of such polymeric matrices with functional agents that possess wide varieties of characteristics require a modified approach towards electrospinning techniques such as coelectrospinning and template spinning. Additional focus within this review is devoted to the state of the art for the implementations of these approaches as viable options for the achievement of multifunctional hybrid nanofibers. Finally, recent advances and challenges, in particular, mass fabrication and prospects of hybrid nanofibers for tissue engineering and biomedical applications have been summarized.

Enhanced postoperative cancer therapy by iron-based hydrogels

Surgical resection is a widely used method for the treatment of solid tumor cancers. However, the inhibition of tumor recurrence and metastasis are the main challenges of postoperative tumor therapy. Traditional intravenous or oral administration have poor chemotherapeutics bioavailability and undesirable systemic toxicity. Polymeric hydrogels with a three-dimensional network structure enable on-site delivery and controlled release of therapeutic drugs with reduced systemic toxicity and have been widely developed for postoperative adjuvant tumor therapy. Among them, because of the simple synthesis, good biocompatibility, biodegradability, injectability, and multifunctionality, iron-based hydrogels have received extensive attention. This review has summarized the general synthesis methods and construction principles of iron-based hydrogels, highlighted the latest progress of iron-based hydrogels in postoperative tumor therapy, including chemotherapy, photothermal therapy, photodynamic therapy, chemo-dynamic therapy, and magnetothermal-chemical combined therapy, etc. In addition, the challenges towards clinical application of iron-based hydrogels have also been discussed. This review is expected to show researchers broad perspectives of novel postoperative tumor therapy strategy and provide new ideas in the design and application of novel iron-based hydrogels to advance this sub field in cancer nanomedicine.

Biomaterials-Based Regenerative Strategies for Skin Tissue Wound Healing

Skin tissue wound healing proceeds through four major stages, including hematoma formation, inflammation, and neo-tissue formation, and culminates with tissue remodeling. These four steps significantly overlap with each other and are aided by various factors such as cells, cytokines (both anti- and pro-inflammatory), and growth factors that aid in the neo-tissue formation. In all these stages, advanced biomaterials provide several functional advantages, such as removing wound exudates, providing cover, transporting oxygen to the wound site, and preventing infection from microbes. In addition, advanced biomaterials serve as vehicles to carry proteins/drug molecules/growth factors and/or antimicrobial agents to the target wound site. In this review, we report recent advancements in biomaterials-based regenerative strategies that augment the skin tissue wound healing process. In conjunction with other medical sciences, designing nanoengineered biomaterials is gaining significant attention for providing numerous functionalities to trigger wound repair. In this regard, we highlight the advent of nanomaterial-based constructs for wound healing, especially those that are being evaluated in clinical settings. Herein, we also emphasize the competence and versatility of the three-dimensional (3D) bioprinting technique for advanced wound management. Finally, we discuss the challenges and clinical perspective of various biomaterial-based wound dressings, along with prospective future directions. With regenerative strategies that utilize a cocktail of cell sources, antimicrobial agents, drugs, and/or growth factors, it is expected that significant patient-specific strategies will be developed in the near future, resulting in complete wound healing with no scar tissue formation.

Green Polymer Nanocomposites for Skin Tissue Engineering

Fabrication of an appropriate skin scaffold needs to meet several standards related to the mechanical and biological properties. Fully natural/green scaffolds with acceptable biodegradability, biocompatibility, and physiological properties quite often suffer from poor mechanical properties. Therefore, for appropriate skin tissue engineering and to mimic the real functions, we need to use synthetic polymers and/or additives as complements to green polymers. Green nanocomposites (either nanoscale natural macromolecules or biopolymers containing nanoparticles) are a class of scaffolds with acceptable biomedical properties window (drug delivery and cardiac, nerve, bone, cartilage as well as skin tissue engineering), enabling one to achieve the required level of skin regeneration and wound healing. In this review, we have collected, summarized, screened, analyzed, and interpreted the properties of green nanocomposites used in skin tissue engineering and wound dressing. We particularly emphasize the mechanical and biological properties that skin cells need to meet when seeded on the scaffold. In this regard, the latest state of the art studies directed at fabrication of skin tissue and bionanocomposites as well as their mechanistic features are discussed, whereas some unspoken complexities and challenges for future developments are highlighted.

In Situ Electrospinning of Aggregation-Induced Emission Nanofibrous Dressing for Wound Healing

Rapid wound dressing and effective antibacterial therapy that meet the extreme requirements of emergency situations are urgently needed for treating skin wounds. Here, an in situ deposited and personalized nanofibrous dressing is reported which can be directly electrospun on skin wounds by a handheld electrospinning device and perfectly fits different wounds of various sizes. Moreover, an aggregation-induced emission luminogen with photodynamic therapy effect is loaded in the nanofibrous dressings which endows the dressing's long-term antibacterial activity during the wound healing process. The in situ electrospun nanofibers show excellent antimicrobial activity against Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus. In vivo studies demonstrate that these antibacterial nanofibrous dressings can effectively reduce inflammation and significantly accelerate wound healing. Such an in situ produced antibacterial dressing is promising as a total solution for treating emergencies, including patient-specific clinical wounds and military injuries.

Potential Wound Healing Effect of Gel Based on Chicha Gum, Chitosan, and Mauritia flexuosa Oil

Wounds are considered a clinically critical issue, and effective treatment will decrease complications, prevent chronic wound formation, and allow rapid healing. The development of products based on naturally occurring materials is an efficient approach to wound healing. Natural polysaccharides can mimic the extracellular matrix and promote cell growth, thus making them attractive for wound healing. In this context, the aim of this work was to produce a gel based on chicha gum, chitosan, and Mauritia flexuosa oil (CGCHO) for wound treatment. TG and DTG analyzed the thermal behavior of the materials, and SEM investigated the surface roughness. The percentages of total phenolic compounds, flavonoids, and antioxidants were determined, presenting a value of 81.811 ± 7.257 µmol gallic acid/g Mauritia flexuosa oil, 57.915 ± 0.305 µmol quercetin/g Mauritia flexuosa oil, and 0.379 mg/mL, respectively. The anti-inflammatory was determined, presenting a value of 10.35 ± 1.46% chicha gum, 16.86 ± 1.00% Mauritia flexuosa oil, 10.17 ± 1.05% CGCHO, and 15.53 ± 0.65% chitosan, respectively. The materials were tested against Gram-negative (Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus) bacteria and a fungus (Candida albicans). The CGCHO formulation showed better antimicrobial activity against Gram-positive bacteria. In addition, an in vivo wound healing study was also performed. After 21 days of treatment, the epidermal re-epithelialization process was observed. CGCHO showed good thermal stability and roughness that can help in cell growth and promote the tissue healing process. In addition to the good results observed for the antimicrobial, antioxidant, anti-inflammatory activities and providing wound healing, they provided the necessary support for the healing process, thus representing a new approach to the wound healing process.

Multi-antibacterial agent-based electrospun polycaprolactone for active wound dressing

Today, due to the greater knowledge of the side effects of chemical drugs and the favorable pharmacological properties of herbal compounds, the use of these compounds is increasing. Since wounds need fast and efficient healing, wound dressing fabrication methods play an important role in wound healing. In this research, electrospinning process was used to prepare samples. Natural antibacterial compounds, such as curcumin, piperine, eugenol, and rutin were loaded in electrospun nano-fibrous based on polycaprolactone. Three-component novel systems of curcumin-piperine-eugenol (PCPiEu), and curcumin-piperine-rutin (PCPiR) were designed and prepared. Their synergistic effect was investigated and also compared with one- and two-component systems. The results showed that medium diameter nanofibers of PCPiEu and PCPiR samples was 198.38 and 142.60, respectively, and they were obtained in smooth, uniform and bead free morphology using optimization of process parameters. The amount of water absorption and water vapor permeability of the three-component samples were in the appropriate range (8.33-10.42 mg cm² h^-1) for wound dressings. The mechanical properties of samples were reduced compared to the control sample, which required further investigation. Antibacterial tests showed good results for partial toxicity of PCPiEu and PCPiR samples. Antibacterial tests showed minor toxicity in PCPiR samples and good results were obtained for PCPiEu samples. In addition, the results showed that PCPiEu and PCPiR samples exhibited antibacterial activity against Gram-positive bacterium Staphylococcus aureus and Gram-negative Enterococcus faecalis bacterium, so that killing ability of 74% and 75% against Gram-positive bacterium and 99.47% and 96.88% against Gram-negative bacterium were obtained for these three systems, respectively.

Construction of targeted drug-loaded composite polysaccharide hydrogels and verification of anti-tumor effect in vitro

A targeted composite polysaccharide drug-loaded gel was obtained and characterized. It displayed potent anti-tumor activity via specific binding between the folate in the gel and the folate receptors in the cell membrane.

Electrospinning and Additive Manufacturing: Adding Three-Dimensionality to Electrospun Scaffolds for Tissue Engineering

The final biochemical and mechanical performance of an implant or scaffold are defined by its structure, as well as the raw materials and processing conditions used during its fabrication. Electrospinning and Additive Manufacturing (AM) are two contrasting processing technologies that have gained popularity amongst the fields of medical research i.e., tissue engineering, implant design, drug delivery. Electrospinning technology is favored for its ability to produce micro- to nanometer fibers from polymer solutions and melts, of which, the dimensions, alignment, porosity, and chemical composition are easily manipulatable to the desired application. AM, on the other hand, offers unrivalled levels of geometrical freedom, allowing highly complex components (i.e., patient-specific) to be built inexpensively within 24 hours. Hence, adopting both technologies together appears to be a progressive step in pursuit of scaffolds that better match the natural architecture of human tissues. Here, we present recent insights into the advances on hybrid scaffolds produced by combining electrospinning (melt electrospinning excluded) and AM, specifically multi-layered architectures consisting of alternating fibers and AM elements, and bioinks reinforced with fibers prior to AM. We discuss how cellular behavior (attachment, migration, and differentiation) is influenced by the co-existence of these micro- and nano-features.

Development of electrospun mats based on hydrophobic hydroxypropyl cellulose derivatives

In this work, hydroxypropyl cellulose esters (HPCE) with long aliphatic chains were prepared and innovatively used in electrospinning to obtain hydroxypropyl cellulose (HPC)-based mats with enhanced resistance to moist environments. The described approach is very simple and does not require any post-treatment (e.g. cross-linking step) to overcome a major problem concerning the premature loss of properties of cellulose-based materials when in contact with moisture. HPCE-based electrospun mats were characterized in terms of their morphology, swelling ability and in vitro hydrolytic degradation. The mats exhibited a swelling capacity of over 115%, depending on the degree of substitution. The in vitro hydrolytic degradation tests showed the high structural integrity of the mats (< 5% weight loss) over a period of 30 days. The in vitro cytotoxicity tests showed that the mats of HPC esters are cytocompatible and promote the adhesion, proliferation and spreading of NIH3T3 fibroblast cells. These data suggest that the HPCE mats may be interesting materials for wound dressings, as well as for other tissue engineering applications.

Functionalized Antimicrobial Nanofibers: Design Criteria and Recent Advances

The rise of antibiotic resistance has become a major threat to human health and it is spreading globally. It can cause common infectious diseases to be difficult to treat and leads to higher medical costs and increased mortality. Hence, multifunctional polymeric nanofibers with distinctive structures and unique physiochemical properties have emerged as a neo-tool to target biofilm and overcome deadly bacterial infections. This review emphasizes electrospun nanofibers' design criteria and properties that can be utilized to enhance their therapeutic activity for antimicrobial therapy. Also, we present recent progress in designing the surface functionalization of antimicrobial nanofibers with non-antibiotic agents for effective antibacterial therapy. Lastly, we discuss the future trends and remaining challenges for polymeric nanofibers.

Decellularised extracellular matrix decorated PCL PolyHIPE scaffolds for enhanced cellular activity, integration and angiogenesis

Wound healing involves a complex series of events where cell–cell and cell-extracellular matrix (ECM) interactions play a key role. Wounding can be simple, such as the loss of the epithelial integrity, or deeper and more complex, reaching to subcutaneous tissues, including blood vessels, muscles and nerves. Rapid neovascularisation of the wounded area is crucial for wound healing as it has a key role in supplying oxygen and nutrients during the highly demanding proliferative phase and transmigration of inflammatory cells to the wound area. One approach to circumvent delayed neovascularisation is the exogenous use of pro-angiogenic factors, which is expensive, highly dose-dependent, and the delivery of them requires a very well-controlled system to avoid leaky, highly permeable and haemorrhagic blood vessel formation. In this study, we decorated polycaprolactone (PCL)-based polymerised high internal phase emulsion (PolyHIPE) scaffolds with fibroblast-derived ECM to assess fibroblast, endothelial cell and keratinocyte activity in vitro and angiogenesis in ex ovo chick chorioallantoic membrane (CAM) assays. Our results showed that the inclusion of ECM in the scaffolds increased the metabolic activity of three types of cells that play a key role in wound healing and stimulated angiogenesis in ex ovo CAM assays over 7 days. Herein, we demonstrated that fibroblast-ECM functionalised PCL PolyHIPE scaffolds appear to have great potential to be used as an active wound dressing to promote angiogenesis and wound healing.

Decellularisation of in vitro generated extracellular matrix (ECM) provides an effective way to stimulate angiogenesis and wound healing.

Developing Wound Dressings Using 2-deoxy-D-Ribose to Induce Angiogenesis as a Backdoor Route for Stimulating the Production of Vascular Endothelial Growth Factor

2-deoxy-D-Ribose (2dDR) was first identified in 1930 in the structure of DNA and discovered as a degradation product of it later when the enzyme thymidine phosphorylase breaks down thymidine into thymine. In 2017, our research group explored the development of wound dressings based on the delivery of this sugar to induce angiogenesis in chronic wounds. In this review, we will survey the small volume of conflicting literature on this and related sugars, some of which are reported to be anti-angiogenic. We review the evidence of 2dDR having the ability to stimulate a range of pro-angiogenic activities in vitro and in a chick pro-angiogenic bioassay and to stimulate new blood vessel formation and wound healing in normal and diabetic rat models. The biological actions of 2dDR were found to be 80 to 100% as effective as VEGF in addition to upregulating the production of VEGF. We then demonstrated the uptake and delivery of the sugar from a range of experimental and commercial dressings. In conclusion, its pro-angiogenic properties combined with its improved stability on storage compared to VEGF, its low cost, and ease of incorporation into a range of established wound dressings make 2dDR an attractive alternative to VEGF for wound dressing development.

Self-Assembled Nanofibrous Marine Collagen Matrix Accelerates Healing of Full-Thickness Wounds

There is an urgent clinical need for wound dressings to treat skin injuries, particularly full-thickness wounds caused by acute and chronic wounds. Marine collagen has emerged as an attractive and safer alternative due to its biocompatibility, diversity, and sustainability. It has minimum risk of zoonotic diseases and less religious constraints as compared to mammalian collagen. In this study, we reported the development of a self-assembled nanofibrous barramundi (Lates calcarifer) collagen matrix (Nano-BCM), which showed good biocompatibility for full-thickness wound-healing applications. The collagen was extracted and purified from barramundi scales and skin. Thereafter, the physicochemical properties of collagen were systematically evaluated. The process to extract barramundi skin collagen (BC) gave an excellent 45% yield and superior purity (∼100%). More importantly, BC demonstrated structural integrity, native triple helix structure, and good thermal stability. BC demonstrated its efficacy in promoting human primary dermal fibroblast (HDF) and immortalized human keratinocytes (HaCaT) proliferation and migration. Nano-BCM has been prepared via self-assembly of collagen molecules in physiological conditions, which resembled the native extracellular matrix (ECM). The clinical therapeutic efficacy of the Nano-BCM was further evaluated in a full-thickness splinted skin wound mice model. In comparison to a clinically used wound dressing (DuoDerm), the Nano-BCM demonstrated significantly accelerated wound closure and re-epithelization. Moreover, Nano-BCM nanofibrous architecture and its ability to facilitate early inflammatory response significantly promoted angiogenesis and differentiated myofibroblast, leading to enhanced wound healing. Consequently, Nano-BCM demonstrates great potential as an economical and effective nonmammalian substitute to achieve skin regeneration.

In vitro and in vivo advancement of multifunctional electrospun nanofiber scaffolds in wound healing applications: Innovative nanofiber designs, stem cell approaches, and future perspectives

The skin is one of the most essential tissues in the human body, interacting with the outside environment and shielding the body from diseases and excessive water loss. Hydrogels, decellularized porcine dermal matrix, and lyophilized polymer scaffolds have all been used in studies of skin wound repair, wound dressing, and skin tissue engineering, however, these materials cannot replicate the nanofibrous architecture of the skin's native extracellular matrix (ECM). Electrospun nanofibers are a fascinating new form of nanomaterials with tremendous potential across a broad spectrum of applications in the biomedical field, including wound dressings, wound healing scaffolds, regenerative medicine, bioengineering of skin tissue, and multifaceted drug delivery. This article reviews recent in vitro and in vivo developments in multifunctional electrospun nanofibers (MENs) for wound healing. This review begins with an introduction to the electrospinning process, its principle, and the processing parameters which have a significant impact on the nanofiber properties. It then discusses the various geometries and advantages of MEN scaffolds produced by different innovative electrospinning techniques for wound healing applications when used in combination with stem cells. This review also discusses some of the possible future nanofiber-based models that could be used. Finally, we conclude with potential perspectives and conclusions in this area.

Recent advances in PVA-polysaccharide based hydrogels and electrospun nanofibers in biomedical applications: A review

Among several types of carbohydrate polymers blend PVA hydrogel membranes used for biomedical applications in particular wound dressings; electrospun nanofibrous membranes have gained increased interest because of their extraordinary features e.g. huge surface area to volume ratio, high porosity, adequate permeability, excellent wound-exudates absorption capacity, architecture similarity with skin ECM and sustained release-profile over long time. In this study, modern perspectives of synthesized/developed electrospun nanofibrous hydrogel membranes based popular carbohydrate polymers blend PVA which recently have been employed for versatile biomedical applications particularly wound dressings, were discussed intensively and compared in detail with traditional fabricated membranes based films, as well. Clinically relevant and advantages of electrospun nanofibrous membranes were discussed in terms of their biocompatibility and easily fabrication and functionalization in different biomedical applications.

Carbonic Anhydrase Carrying Electrospun Nanofibers for Biocatalysis Applications

BACKGROUND

Enzymes are efficient biocatalysis that catalysis a large number of reactions due to their chemical, regional, or stereo specifities and selectivity. Their usage in bioreactor or biosensor systems has great importance. Carbonic anhydrase enzyme catalyzes the interconversion between carbon dioxide and water and the dissociated ions of carbonic acid. In organisms, the carbonic anhydrase enzyme has crucial roles connected with pH and CO₂ homeostasis, respiration, and transport of CO₂/bicarbonate, etc. So, immobilization of the enzyme is important in stabilizing the catalyst against thermal and chemical denaturation in bioreactor systems when compared to the free enzyme that is unstable at high temperatures and extreme pH values, as well as in the presence of organic solvents or toxic reagents. Nano-scale composite materials have attracted considerable attention in recent years, and electrospinning based all-nanocomposite materials have a wide range of applications. In this study, electrospun nanofibers were fabricated and used for the supporting media for carbonic anhydrase enzyme immobilization to enhance the enzyme storage and usage facilities.

OBJECTIVE

In this article, our motivation is to obtain attractive electrospun support for carbonic anhydrase enzyme immobilization to enhance the enzyme reusability and storage ability in biocatalysis applications.

METHODS

In this article, we propose electrospun nanofibers for carbonic anhydrase carrying support for achieving our aforementioned object. In the first part of the study, agar with polyacrylonitrile (PAN) nanofibers was directly fabricated from an agar-PAN mixture solution using the electrospinning method, and fabricated nanofibers were cross-linked via glutaraldehyde (GA). The morphology, chemical structure, and stability of the electrospun nanofibers were characterized. In the second part of the study, the carbonic anhydrase enzyme was immobilized onto fabricated electrospun nanofibers. Then, enzyme activity, the parameters that affect enzyme immobilization such as pH, enzyme amount, immobilization time, etc. and reusability were investigated.

RESULTS

When the scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analysis results are combined in the characterization process of the synthesized electrospun nanofibers, the optimum cross-linking time is found to be 8 hours using 5% glutaraldehyde cross-linking agent. Then, thermal stability measurements showed that the thermal stability of electrospun nanofibers has an excellent characteristic for biomedical applications. The optimum temperature value was found 37°C, pH 8 was determined as an optimum pH, and 100 ppm carbonic anhydrase enzyme concentration was found to be optimum enzyme concentration for the carbonic anhydrase enzyme immobilization. According to the kinetic data, carbonic anhydrase immobilized electrospun nanofibers acted as a biocatalyst in the conversion of the substrate to the product in 83.98%, and immobilized carbonic anhydrase enzyme is reusable up to 9 cycles in biocatalysis applications.

CONCLUSION

After applying the framework, we get a new biocatalysis application platform for carbonic anhydrase enzyme. Electrospun nanofibers were chosen as the support material for enzyme immobilization. By using this approach, the carbonic anhydrase enzyme could easily be used in the industrial area by cost-effective advantageous aspects.

Electrospinning for drug delivery applications: A review

Drug delivery devices are promising tools in the pharmaceutical field, as they are able to maximize the therapeutic effects of the delivered drug while minimizing the undesired side effects. In the past years, electrospun nanofibers attracted rising attention due to their unique features, like biocompatibility and broad flexibility. Incorporation of active principles in nanofibrous meshes proved to be an efficient method for in situ delivery of a wide range of drugs, expanding the possibility and applicability of those devices. In this review, the principle of electrospinning and different fields of applications are treated to give an overview of the recent literature, underlining the easy tuning and endless combination of this technique, that in the future could be the new frontier of personalized medicine.

Recent Advances in Fiber-Hydrogel Composites for Wound Healing and Drug Delivery Systems

In the last decades, much research has been done to fasten wound healing and target-direct drug delivery. Hydrogel-based scaffolds have been a recurrent solution in both cases, with some reaching already the market, even though their mechanical stability remains a challenge. To overcome this limitation, reinforcement of hydrogels with fibers has been explored. The structural resemblance of fiber-hydrogel composites to natural tissues has been a driving force for the optimization and exploration of these systems in biomedicine. Indeed, the combination of hydrogel-forming techniques and fiber spinning approaches has been crucial in the development of scaffolding systems with improved mechanical strength and medicinal properties. In this review, a comprehensive overview of the recently developed fiber-hydrogel composite strategies for wound healing and drug delivery is provided. The methodologies employed in fiber and hydrogel formation are also highlighted, together with the most compatible polymer combinations, as well as drug incorporation approaches creating stimuli-sensitive and triggered drug release towards an enhanced host response.

Extracellular matrix biomimetic polymeric membranes enriched with silver nanoparticles for wound healing

Severe skin injuries, including burns, represent a real concern for the global health-care system and therefore, there is an increased interest in developing wound dressings, in order to stimulate and enhance skin tissue repair. The aim of this study was to design novel hybrid materials, biomimetic to skin extracellular matrix and enriched with silver nanoparticles (nAg), in order to provide both dermal tissue regeneration and antimicrobial activity. Two material variants (variant A and variant B) consisting of type I collagen (COL), chondroitin sulfate (CS) and k-elastin peptides (EL) enriched with positively-charged nAg, were conditioned as membranes. UV exposure ensured both sterilisation and cross-linking of the materials. Physico-chemical characterization of the hybrid biomaterials showed values of density and swelling degree higher than those of COL membrane, while the process of in vitro degradation followed a similar pattern. Infrared spectroscopy and X-ray diffraction indicated alterations of the characteristic structural features and crystallinity of COL after blending with CS and EL and nAg embedding. Scanning electron microscopy observations revealed different surface morphologies of the hybrid membranes, according to their composition. In vitro studies on L929 fibroblasts and HaCaT keratinocytes showed that both hybrid membranes exhibited good cytocompatibility and promoted higher cell proliferation compared to COL sample, as evaluated by MTT and Live/Dead assays. The presence of actin filaments highlighted by fluorescent labelling confirmed the fibroblast and keratinocyte adhesion onto the surface of hybrid membranes. Most importantly, both materials showed an increased wound healing ability in an in vitro scratch assay model, stimulating cell migration at 24 h post-seeding. In addition, good antimicrobial activity was recorded, especially against Gram-positive bacterial strain. Altogether, our findings recommend COL-CS-EL-nAg hybrid membranes as good candidates for wound healing acceleration and bioengineering of skin tissue.

Electrospun Asymmetric Membranes as Promising Wound Dressings: A Review

Despite all the efforts that have been done up to now, the currently available wound dressings are still unable to fully re-establish all the structural and functional properties of the native skin. To overcome this situation, researchers from the tissue engineering area have been developing new wound dressings (hydrogels, films, sponges, membranes) aiming to mimic all the features of native skin. Among them, asymmetric membranes emerged as a promising solution since they reproduce both epidermal and dermal skin layers. Wet or dry/wet phase inversion, scCO2-assisted phase inversion, and electrospinning have been the most used techniques to produce such a type of membranes. Among them, the electrospinning technique, due to its versatility, allows the development of multifunctional dressings, using natural and/or synthetic polymers, which resemble the extracellular matrix of native skin as well as address the specific requirements of each skin layer. Moreover, various therapeutic or antimicrobial agents have been loaded within nanofibers to further improve the wound healing performance of these membranes. This review article provides an overview of the application of asymmetric electrospun membranes as wound dressings displaying antibacterial activity and as delivery systems of biomolecules that act as wound healing enhancers.