Electrospun Janus nanofibers loaded with a drug and inorganic nanoparticles as an effective antibacterial wound dressing

Cellulose-Based Nanofibers Infused with Biotherapeutics for Enhanced Wound-Healing Applications

Nanofibers fabricated from various materials such as polymers, carbon, and semiconductors have been widely used for wound healing and tissue engineering applications due to their excellent nontoxic, biocompatible, and biodegradable properties. Nanofibers with a diameter in the nanometer range possess a larger surface area per unit mass permitting easier addition of surface functionalities and release of biotherapeutics incorporated compared with conventional polymeric microfibers. Henceforth, nanofibers are a choice for fabricating scaffolds for the management of wound healing. Nanofibrous scaffolds have emerged as a promising method for fabricating wound dressings since they mimic the fibrous dermal extracellular matrix milieu that offers structural support for wound healing and functional signals for guiding tissue regeneration. Cellulose-based nanofibers have gained significant attention among researchers in the fabrication of on-site biodegradable scaffolds fortified with biotherapeutics in the management of wound healing. Cellulose is a linear, stereoregular insoluble polymer built from repeated units of d-glucopyranose linked with 1,4-β glycoside bonds with a complex and multilevel supramolecular architecture. Cellulose is a choice and has been used by various researchers due to its solubility in many solvents and its capacity for self-assembly into nanofibers, facilitating the mimicry of the natural extracellular matrix fibrous architecture and promoting substantial water retention. It is also abundant and demonstrates low immunogenicity in humans due to its nonanimal origins. To this end, cellulose-based nanofibers have been studied for protein delivery, antibacterial activity, and biosensor applications, among others. Taken together, this review delves into an update on cellulose-based nanofibers fused with bioactive compounds that have not been explored considerably in the past few years.

Electrospinning in Drug Delivery: Progress and Future Outlook

There is intense research during the past few decades to design and fabricate drug delivery systems using the electrospinning system. Electrospinning is an efficient technique to produce nanofiber materials with different dimensions and morphologies by adjusting the processing parameters. Electrospinning is becoming an innovative technology that promotes the pursuit and maintenance of human health. Herein, the review discusses the contribution of electrospinning technology in drug delivery systems, summarising the modification of the various electrospinning system configurations and the effects of the process parameters on fibers, their application in drug delivery including carrier materials, loaded drugs and their release mechanisms and illustrates their various medical applications. Finally, this review discusses the challenges, bottlenecks, and development prospects of electrospinning technology in the field of drug delivery in terms of scaling up for clinical use and exploring potential solutions to pave the way to establish electrospinning for future drug delivery systems.

Directional Liquid Transport in Thin Fibrous Matrices: Enhancement of Advanced Applications

Directional liquid transport fibrous matrices (DLTFMs) have the unique ability to direct liquid movement in a single direction through their thickness. Beyond their inherent liquid transport function, DLTFMs can also enhance the effectiveness of additional functionalities. This review focuses on recent advances in DLTFMs, particularly the role of DLTs in enhancing secondary functions. We begin with a brief overview of the historical development and major achievements in DLTFM research, followed by an outline of the classification, fabrication techniques, and basic functions derived from their natural liquid transport properties. The integration of DLT to enhance secondary functionalities such as responsiveness, thermal regulation, and wearable technology for innovative applications in various sectors is then discussed. The review concludes with a discussion of key challenges and prospects in the field, including the durability and reliability of DLT performance, the precise regulation of fluid transport rates, the resilience and longevity of DLTFMs in harsh environments, and the impact of DLT variations on performance enhancement. The goal of this review is to stimulate further innovative studies on DLTFMs and to promote their practical implementation in a variety of industries.

Serine-modified silver nanoparticle porous spray membrane: A novel approach to wound infection prevention and inflammation reduction

Traditional wound care preparations frequently face challenges such as complex care protocols, poor patient compliance, limited skin permeability, lack of aesthetics, and inconvenience, in addition to the risk of bacterial infection. We developed a spray film preparation containing nanocellulose and L-serine modified nanosilver, capable of rapidly forming a transparent film on the skin within minutes of application. The incorporation of nanocellulose imparted protective, moisturizing, and breathable properties to the film, allowing for easy removal after use. Moreover, our innovative application of L-serine as a precursor for synthesizing silver nanoparticles not only overcomed the limitations of current silver nanoparticle synthesis methods but also enhanced antibacterial efficacy by leveraging the inherent antimicrobial properties and bacterial targeting capability of L-serine. Specifically, the addition of nanocellulose to the spray film forming system enhanced air permeability and drug carrying capacity by creating a lightweight porous structure, while also ensuring the antimicrobial and anti-inflammatory efficacy of serine modified silver nanoparticles. Mice treated with spray film formulations containing nanocellulose and silver nanoparticles demonstrated superior wound healing, normalization of keratin thickness, increased hair follicle count, and reduced inflammatory markers. In conclusion, our study developed a spray film that integrated excellent antimicrobial properties with user convenience. This research presented innovative strategies for clinical wound care, antibacterial infection management, and post laser cosmetic treatment, with the potential to substantially enhance wound care in practical application.

Fiber Technology in Drug Delivery and Pharmaceuticals

The field of fiber technology is a dynamic and innovative domain that offers novel solutions for controlled and targeted therapeutic interventions. This abstract provides an overview of key aspects within this field, encompassing a range of techniques, applications, commercial developments, intellectual property, and regulatory considerations. The foundational introduction establishes the significance of fiber-based drug delivery systems. Electrospinning, a pivotal technique, has been explored in this paper, along with its various methods and applications. Monoaxial, coaxial, triaxial, and side-by-side electrospinning techniques each offer distinct advantages and applications. Centrifugal spinning, solution and melt blowing spinning, and pressurized gyration further contribute to the field's diversity. The review also delves into commercial advancements, highlighting marketed products that have successfully harnessed fiber technology. The role of intellectual property is acknowledged, with patents reflecting the innovative strides in fiber-based drug delivery. The regulatory perspective, essential for ensuring safety and efficacy, is discussed in the context of global regulatory agencies' evaluations. This review encapsulates the multidimensional nature of fiber technology in drug delivery and pharmaceuticals, showcasing its potential to revolutionize medical treatments and underscores the importance of continued collaboration between researchers, industry, and regulators for its advancement.

Natural polymer nanofiber dressings for effective management of chronic diabetic wounds: A comprehensive review

Diabetic wounds present a chronic challenge in effective treatment. Natural polymer nanofiber dressings have emerged as a promising solution due to their impressive biocompatibility, biodegradability, safety, high specific surface area, and resemblance to the extracellular matrix. These qualities make them ideal materials with excellent biological properties and cost-effectiveness. Additionally, they can effectively deliver therapeutic agents, enabling diverse treatment effects. This review offers a comprehensive overview of natural polymer-based nanofibers in diabetic wound dressings. It examines the characteristics and challenges associated with diabetic wounds and the role of natural polymers in facilitating wound healing. The review highlights the preparation, mechanism, and applications of various functional dressings composed of natural polymer nanofibers. Furthermore, it addresses the main challenges and future directions in utilizing natural polymer nanofibers for diabetic wound treatment, providing valuable insights into effective wound management for diabetic patients.

Electrospun PVDF/PVP Fibrous Membrane with Photocatalytic and Superhydrophilic Properties

Membrane separation technology is used to treat environmental wastewater, but during the treatment process, the occurrence of membrane fouling greatly affects the treatment efficiency. To address this phenomenon, improve membrane antipollution capabilities, and treat organic wastewater, photocatalysis and membrane separation technology have been coupled, forming a suitable and promising treatment method. Here, we propose a simple strategy to prepare a polyvinylidene fluoride/polyvinyl pyrrolidone nitrogen-doped titanium dioxide fibrous membrane (PVDF/PVP N-doped TiO2 fibrous membrane). The experimental results showed that PVDF and PVP mixed spinning made the fibrous membrane have a unique microstructure, and the superhydrophobic PVDF fibrous membrane was changed into superhydrophilic. In addition, electrospraying technology was used to attach TiO2 nanoparticles (NPs) to the fiber, and nitrogen (N) was doped in this process to improve the photocatalytic activity of the fibrous membrane. Finally, methyl blue solution was used as the target organic pollutant. Under the irradiation of a xenon lamp, 90.05% of methyl blue was removed within 90 min, indicating that the membrane had good photocatalytic performance. In a water contact angle test, the PVDF/PVP N-doped TiO2 fibrous membrane showed superhydrophilicity. The design of a fibrous membrane with high photocatalytic activity and superhydrophilicity properties has great potential for practical application in the purification of industrial wastewater.

The ASB@HNTs-PVA nanofiber membrane, possessing both anti-inflammatory and hemostatic activities, promotes the healing of T2D skin wounds

The healing of diabetic wounds has long been a significant challenge in the field of medicine. The elevated sugar levels surrounding diabetic wounds create a conducive environment for harmful bacterial growth, resulting in purulent infections that impede the healing process. Thus, the development of a biomaterial that can enhance the healing of diabetic wounds holds great importance. This study developed electrospun dressings for wound healing by combining traditional Chinese medicine and clay. The study utilized electrospinning technology to prepare polyvinyl alcohol (PVA) nanofiber membranes containing ASB and HNTs. These ASB@HNTs-PVA nanofiber membranes demonstrated rapid hemostasis, along with antibacterial and anti-inflammatory properties, facilitating the recovery of type 2 diabetic (T2D) wounds. Various analyses were conducted to assess the performance of the composite nanofiber membrane, including investigations into its biocompatibility and hemostatic abilities through antibacterial experiments, cell experiments, and mouse liver tail bleeding experiments. Western blot analysis confirmed that the composite nanofiber membrane could decrease the levels of inflammatory factors IL-1β and TNF-α. A type 2 diabetic mouse model was utilized, with wounds artificially induced on the backs of mice. Application of the nanofiber membrane to the wounds further confirmed its anti-inflammatory effects and ability to enhance wound healing in vivo.

Advances of antimicrobial dressings loaded with antimicrobial agents in infected wounds

Wound healing is a complex process that is critical for maintaining the barrier function of the skin. However, when a large quantity of microorganisms invade damaged skin for an extended period, they can cause local and systemic inflammatory responses. If left untreated, this condition may lead to chronic infected wounds. Infected wounds significantly escalate wound management costs worldwide and impose a substantial burden on patients and healthcare systems. Recent clinical trial results suggest that the utilization of effective antimicrobial wound dressing could represent the simplest and most cost-effective strategy for treating infected wounds, but there has hitherto been no comprehensive evaluation reported on the efficacy of antimicrobial wound dressings in promoting wound healing. Therefore, this review aims to systematically summarize the various types of antimicrobial wound dressings and the current research on antimicrobial agents, thereby providing new insights for the innovative treatment of infected wounds.

Tunable ciprofloxacin delivery through personalized electrospun patches for tympanic membrane perforations

Approximately 740 million symptomatic patients are affected by otitis media every year. Being an inflammatory disease affecting the middle ear, it is one of the primary causes of tympanic membrane (TM) perforations, often resulting in impaired hearing abilities. Antibiotic therapy using broad-spectrum fluoroquinolones, such as ciprofloxacin (CIP), is frequently employed and considered the optimal route to treat otitis media. However, patients often get exposed to high dosages to compensate for the low drug concentration reaching the affected site. Therefore, this study aims to integrate tissue engineering with drug delivery strategies to create biomimetic scaffolds promoting TM regeneration while facilitating a localized release of CIP. Distinct electrospinning (ES) modalities were designed in this regard either by blending CIP into the polymer ES solution or by incorporating nanoparticles-based co-ES/electrospraying. The combination of these modalities was investigated as well. A broad range of release kinetic profiles was achieved from the fabricated scaffolds, thereby offering a wide spectrum of antibiotic concentrations that could serve patients with diverse therapeutic needs. Furthermore, the incorporation of CIP into the TM patches demonstrated a favorable influence on their resultant mechanical properties. Biological studies performed with human mesenchymal stromal cells confirmed the absence of any cytotoxic or anti-proliferative effects from the released antibiotic. Finally, antibacterial assays validated the efficacy of CIP-loaded scaffolds in suppressing bacterial infections, highlighting their promising relevance for TM applications.

Fluid Unidirectional Transport Induced by Structure and Ambient Elements across Porous Materials: From Principles to Applications

Spontaneous or nonspontaneous unidirectional fluid transport across multidimension can occur under specific structural designs and ambient elements for porous materials. While existing reviews have extensively summarized unidirectional fluid transport on surfaces, there is an absence of literature summarizing fluid's unidirectional transport across porous materials. This review introduces wetting phenomena observed on natural biological surfaces or porous structures. Subsequently, it offers an overview of diverse principles and potential applications in this field, emphasizing various physical and chemical structural designs (surface energy, capillary size, topographic curvature) and ambient elements (underwater, under oil, pressure, and solar energy). Applications encompass moisture-wicking fabric, sensors, skincare, fog collection, oil-water separation, electrochemistry, liquid-based gating, and solar evaporators. Additionally, significant principles and formulas from various studies are compelled to offer readers valuable references. Simultaneously, potential advantages and challenges are critically assessed in these applications and the perspectives are presented.

Application and Development of Electrospun Nanofiber Scaffolds for Bone Tissue Engineering

Nanofiber scaffolds have gained significant attention in the field of bone tissue engineering. Electrospinning, a straightforward and efficient technique for producing nanofibers, has been extensively researched. When used in bone tissue engineering scaffolds, electrospun nanofibers with suitable surface properties promote new bone tissue growth and enhance cell adhesion. Recent advancements in electrospinning technology have provided innovative approaches for scaffold fabrication in bone tissue engineering. This review comprehensively examines the utilization of electrospun nanofibers in bone tissue engineering scaffolds and evaluates the relevant literature. The review begins by presenting the fundamental principles and methodologies of electrospinning. It then discusses various materials used in the production of electrospun nanofiber scaffolds for bone tissue engineering, including natural and synthetic polymers, as well as certain inorganic materials. The challenges associated with these materials are also described. The review focuses on novel electrospinning techniques for scaffold construction in bone tissue engineering, such as multilayer nanofibers, multifluid electrospinning, and the integration of electrospinning with other methods. Recent advancements in electrospinning technology have enabled the fabrication of precisely aligned nanofiber scaffolds with nanoscale architectures. These innovative methods also facilitate the fabrication of biomimetic structures, wherein bioactive substances can be incorporated and released in a controlled manner for drug delivery purposes. Moreover, they address issues encountered with traditional electrospun nanofibers, such as mechanical characteristics and biocompatibility. Consequently, the development and implementation of novel electrospinning technologies have revolutionized scaffold fabrication for bone tissue engineering.

Alginate-Based Electrospun Nanofibers and the Enabled Drug Controlled Release Profiles: A Review

Alginate is a natural polymer with good biocompatible properties and is a potential polymeric material for the sustainable development and replacement of petroleum derivatives. However, the non-spinnability of pure alginate solutions has hindered the expansion of alginate applications. With the continuous development of electrospinning technology, synthetic polymers, such as PEO and PVA, are used as co-spinning agents to increase the spinnability of alginate. Moreover, the coaxial, parallel Janus, tertiary and other diverse and novel electrospun fiber structures prepared by multi-fluid electrospinning have found a new breakthrough for the problem of poor spinning of natural polymers. Meanwhile, the diverse electrospun fiber structures effectively achieve multiple release modes of drugs. The powerful combination of alginate and electrostatic spinning is widely used in many biomedical fields, such as tissue engineering, regenerative engineering, bioscaffolds, and drug delivery, and the research fever continues to climb. This is particularly true for the controlled delivery aspect of drugs. This review provides a brief overview of alginate, introduces new advances in electrostatic spinning, and highlights the research progress of alginate-based electrospun nanofibers in achieving various controlled release modes, such as pulsed release, sustained release, biphasic release, responsive release, and targeted release.

Novel Saccharomyces cerevisiae-Loaded Polyvinylpyrrolidone/SiO2 Nanofiber for Wound Dressing Prepared Using Electrospinning Method

Electrospun nanofibers have been used as wound dressings to protect skin from infection and promote wound healing. In this study, we developed polyvinylpyrrolidone (PVP)/silicon dioxide (SD) composite nanofibers for the delivery of probiotic Saccharomyces cerevisiae (SC), which potentially aids in wound healing. PVP/SD composite nanofibers were optimized through electrospinning, and bead-free nanofibers with an average diameter of 624.7 ± 99.6 nm were fabricated. Next, SC, a wound-healing material, was loaded onto the PVP/SD composite nanofibers. SC was encapsulated in nanofibers, and nanofibers were prepared using SC, PVP, SD, water, and ethanol in a ratio of 3:4:0.1:4.8:1.2. The formation of smooth nanofibers with protrusions around SC was confirmed using SEM. Nanofiber dressing properties were physicochemically and mechanically characterized by evaluating SEM, DSC, XRD, and FTIR images, tensile strength, and elongation at break. Additionally, a release test of active substances was performed. The absence of interactions between SC, PVP, and SD was confirmed through physicochemical evaluation, and SEM images showed that the nanofiber dressing contained SC and had a porous structure. It also showed a 100% release of SC within 30 min. Overall, our study showed that SC-loaded PVP/SD composite nanofibers prepared using the electrospinning method are promising wound dressings.

Multifunctional antibacterial hydrogels for chronic wound management

Chronic wounds have gradually evolved into a global health challenge, comprising long-term non-healing wounds, local tissue necrosis, and even amputation in severe cases. Accordingly, chronic wounds place a considerable psychological and economic burden on patients and society. Chronic wounds have multifaceted pathogenesis involving excessive inflammation, insufficient angiogenesis, and elevated reactive oxygen species levels, with bacterial infection playing a crucial role. Hydrogels, renowned for their excellent biocompatibility, moisture retention, swelling properties, and oxygen permeability, have emerged as promising wound repair dressings. However, hydrogels with singular functions fall short of addressing the complex requirements associated with chronic wound healing. Hence, current research emphasises the development of multifunctional antibacterial hydrogels. This article reviews chronic wound characteristics and the properties and classification of antibacterial hydrogels, as well as their potential application in chronic wound management.

3D-printed electrospun fibres for wound healing

Wound management for acute and chronic wounds has become a serious clinical problem worldwide, placing considerable pressure on public health systems. Owing to the high-precision, adjustable pore structure, and repeatable manufacturing process, 3D-printed electrospun fibre (3DP-ESF) has attracted widespread attention for fabricating wound dressing. In addition, in comparison with 2D electrospun fibre membranes fabricated by traditional electrospinning, the 3D structures provide additional guidance on cell behaviour. In this perspective article, we first summarise the basic manufacturing principles and methods to fabricate 3DP-ESF. Then, we discuss the function of 3DP-ESF in manipulating the different stages of wound healing, including anti-bacteria, anti-inflammation, and promotion of cell migration and proliferation, as well as the construction of tissue-engineered scaffolds. In the end, we provide the current challenge faced by 3DP-ESF in the application of skin wound regeneration and its promising future directions.

PAA-PU Janus Hydrogels Stabilized by Janus Particles and its Interfacial Performance During Hemostatic Processing

Hydrogel is a very promising dressing for hemostasis and wound healing due to its good adhesion and long-term moist environment. However, secondary injury caused by tissue adhesion due to homogeneous hydrogel cannot be ignored. The obvious interface existing in Janus hydrogel will weaken its asymmetric function. Here, a hierarchical adhesive polyacrylic acid-polyurushiol water-oil Janus hydrogel (JPs@PAA-PU) without adhesive layer is fabricated by one-pot method in the stabilization of polystyrene@silica-siliver Janus particles (JPs). The morphological structure, mechanical properties, anisotropic chemical composition, and adhesion performance, in vivo, and in vitro hemostatic properties of Janus hydrogel are investigated. Result shows that the obtained Janus hydrogel possesses obvious compartmentalization in microstructure, functional groups, and chemical elements. Janus hydrogel is provided with asymmetric interfacial toughness with top 52.45 ± 2.29 Kpa and bottom 7.04 ± 0.88 Kpa on porcine liver. The adhesion properties of PAA side to tissue, red blood cells and platelets, promoting effect of PU side on coagulation cascade reaction and its physical battier endow Janus hydrogel with shorter hemostatic time and less blood loss than control group. It also exhibits excellent antibacterial effects against Escherichia coli and Staphylococcus aureus (>90%). Janus hydrogel possesses biosafety, providing safety guarantee for clinical applications in the future.

Recent progress of electrospun nanofibers as burning dressings

Burns are a global public health problem, which brings great challenges to public health and the economy. Severe burns often lead to systemic infection, shock, multiple organ failure, and even death. With the increasing demand for the therapeutic effect of burn wounds, traditional dressings have been unable to meet people's needs due to their single function and many side effects. In this context, electrospinning shows a great prospect on the way to open up advanced wound dressings that promote wound repairing and prevent infection. With its large specific surface area, high porosity, and similar to natural extracellular matrix (ECM), electrospun nanofibers can load drugs and accelerate wound healing. It provides a promising solution for the treatment and management of burn wounds. This review article introduces the concept of burn and the types of electrospun nanofibers, then summarizes the polymers used in electrospun nanofiber dressings. Finally, the drugs (plant extracts, small molecule drugs and nanoparticles) loaded with electrospun burn dressings are summarized. Some promising aspects for developing commercial electrospun burn dressings are proposed.

Advanced biomass-based Janus materials: Classification, preparation and application: A review

In contrast to conventional particles characterized by isotropic surfaces, Janus particles possess anisotropic surfaces, resulting in unique physicochemical properties and functional attributes. In recent times, there has been a surge in interest regarding the synthesis of Janus particles using biological macromolecules. Various synthesis techniques have been developed for the fabrication of Janus materials derived from biomass. These methods include electrospinning, freeze-drying, secondary casting film formation, self-assembly technology, and other approaches. In the realm of Janus composite materials, those derived from biomass have found extensive applications in diverse domains including oil-water separation, sensors, photocatalysis, and medical materials. This article provides a systematic introduction to the classification of Janus materials, with a specific focus on various types of biomass-based Janus materials (mainly cellulose-based Janus materials, lignin-based Janus materials and protein-based Janus materials) and the methods used for their preparation. This work will not only deepen the understanding of biomass-based Janus materials, but also contribute to the development of new methods for designing biomass-based Janus structures to optimize biomass utilization.

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.

Trends in the Incorporation of Antiseptics into Natural Polymer-Based Nanofibrous Mats

Nanofibrous materials represent a very promising form of advanced carrier systems that can be used industrially, especially in regenerative medicine as highly functional bandages, or advanced wound dressings. By incorporation of antimicrobial additives directly into the structure of the nanofiber carrier, the functionality of the layer is upgraded, depending on the final requirement-bactericidal, bacteriostatic, antiseptic, or a generally antimicrobial effect. Such highly functional nanofibrous layers can be prepared mostly by electrospinning technology from both synthetic and natural polymers. The presence of a natural polymer in the composition is very advantageous. Especially in medical applications where, due to the presence of the material close to the human body, the healing process is more efficient and without the occurrence of an unwanted inflammatory response. However, converting natural polymers into nanofibrous form, with a homogeneously distributed and stable additive, is a great challenge. Thus, a combination of natural and synthetic materials is often used. This review clearly summarizes the issue of the incorporation and effectiveness of different types of antimicrobial substances, such as nanoparticles, antibiotics, common antiseptics, or substances of natural origin, into electrospun nanofibrous layers made of mostly natural polymer materials. A section describing the problematic aspects of antimicrobial polymers is also included.

Chitosan-Stabilized CuO Nanostructure-Functionalized UV-Crosslinked PVA/Chitosan Electrospun Membrane as Enhanced Wound Dressing

Electrospun nanofibrous membranes are of great interest for tissue engineering, active material delivery, and wound dressing. These nanofibers possess unique three-dimensional (3D) interconnected porous structures that result in a higher surface-area-to-volume ratio and porosity. This study was carried out to prepare nanofibrous membranes by electrospinning a blend of PVA/chitosan polymeric solution functionalized with different ratios of copper oxide. Chitosan-stabilized CuO nanoparticles (CH-CuO NPs) were biosynthesized successfully utilizing chitosan as the capping and reducing agent. XRD analysis confirmed the monoclinic structure of CH-CuO NPs. In addition, the electrospun nanofibrous membranes were UV-crosslinked for a definite time. The membranes containing CH-CuO NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectrophotometry, and dynamic light scattering (DLS). SEM results showed the nanosize of the fiber diameter in the range of 147-207 nm. The FTIR spectroscopy results indicated the successful incorporation of CH-CuO NPs into the PVA/chitosan nanofibrous membranes. DSC analysis proved the enhanced thermal stability of the nanofibrous membranes due to UV-crosslinking. Swelling and degradation tests were carried out to ensure membrane stability. Greater antimicrobial activity was observed in the nanoparticle-loaded membrane. An in vitro release study of Cu2+ ions from the membrane was carried out for 24 h. The cytotoxicity of CH-CuO NP-incorporated membranes was investigated to estimate the safe dose of nanoparticles. An in vivo test using the CH-CuO NP-loaded PVA/chitosan membrane was conducted on a mice model, in which wound healing occurred in approximately 12 days. These results confirmed that the biocompatible, nontoxic nanofibrous membranes are ideal for wound-dressing applications.

An injectable collagen peptide-based hydrogel with desirable antibacterial, self-healing and wound-healing properties based on multiple-dynamic crosslinking

Conventional collagen-based hydrogels as wound dressing materials are usually lack of antibacterial activity and easily broken when encountering external forces. In this work, we developed a collagen peptide-based hydrogel as a wound dressing, which was composed of adipic acid dihydrazide functionalized collagen peptide (Col-ADH), oxidized dextran (ODex), polyvinyl alcohol (PVA) and borax via multiple-dynamic reversible bonds (acylhydrazone, amine, borate ester and hydrogen bonds). The injectable hydrogel exhibited satisfactory self-healing ability, antibacterial activity, mechanical strength, as well as good biocompatibility and biodegradability. In vivo experiments demonstrated the rapid hemostasis, accelerated cell migration, and promoted wound healing capacities of the hydrogel. These results indicate that the multifunctional collagen peptide-based hydrogel has great potentials in the field of wound dressings.

Functional electrospun nanofibers: fabrication, properties, and applications in wound-healing process

Electrostatic spinning as a technique for producing nanoscale fibers has recently attracted increasing attention due to its simplicity, versatility, and loadability. Nanofibers prepared by electrostatic spinning have been widely studied, especially in biomedical applications, because of their high specific surface area, high porosity, easy size control, and easy surface functionalization. Wound healing is a highly complex and dynamic process that is a crucial step in the body's healing process to recover from tissue injury or other forms of damage. Single-component nanofibers are more or less limited in terms of structural properties and do not fully satisfy various needs of the materials. This review aims to provide an in-depth analysis of the literature on the use of electrostatically spun nanofibers to promote wound healing, to overview the infinite possibilities for researchers to tap into their biomedical applications through functional composite modification of nanofibers for advanced and multifunctional materials, and to propose directions and perspectives for future research.

On-Demand Sequential Release of Dual Drug from pH-Responsive Electrospun Janus Nanofiber Membranes toward Wound Healing and Infection Control

Drugs against bacteria and abnormal cells, such as antibiotics and anticancer drugs, may save human lives. However, drug resistance is becoming more common in the clinical world. Nowadays, a synergistic action of multiple bioactive compounds and their combination with smart nanoplatforms has been considered an alternative therapeutic strategy to fight drug resistance in multidrug-resistant cancers and microorganisms. The present study reports a one-step fabrication of innovative pH-responsive Janus nanofibers loaded with two active compounds, each in separate polymer compartments for synergistic combination therapy. By dissolving one of the compartments from the nanofibers, we could clearly demonstrate a highly yielded anisotropic Janus structure with two faces by scanning electron microscopy (SEM) analysis. To better understand the distinctive attributes of Janus nanofibers, several analytical methods, such as X-ray diffraction (XRD), FTIR spectroscopy, and contact angle goniometry, were utilized to examine and compare them to those of monolithic nanofibers. Furthermore, a drug release test was conducted in pH 7.4 and 6.0 media since the properties of Janus nanofibers correlate significantly with different environmental pH levels. This resulted in the on-demand sequential codelivery of octenidine (OCT) and curcumin (CUR) to the corresponding pH stimulus. Accordingly, the antibacterial properties of Janus fibers against Escherichia coli and Staphylococcus aureus, tested in a suspension test, were pH-dependent, i.e., greater in pH 6 due to the synergistic action of two active compounds, and Eudragit E100 (EE), and highly satisfactory. The biocompatibility of the Janus fibers was confirmed in selected tests.

Hydrogen sulfide releasing poly(γ-glutamic acid) biocomposite hydrogel with monitoring, antioxidant, and antibacterial properties for diabetic wound healing

Adverse factors such as high levels of glucose, oxidative stress, inflammation, and bacterial infection impede diabetic wound healing and even worsen wounds. Owing to its outstanding anti-inflammatory and antioxidant properties as well as the potential to promote cell migration and proliferation, hydrogen sulfide(H2S) gas therapy is promising for chronic diabetic wound recovery. In this work, a multifunctional poly(γ-glutamic acid)(PGA) hydrogel encapsulated with keratin-based H2S donor(KTC), ciprofloxacin(Cip), and anthocyanins(Ant) was developed. The resultant hydrogel was capable of releasing H2S, thereby promoting cell proliferation and enhancing anti-inflammation and antioxidant activity. The release of antibiotic Cip was accelerated under a diabetic wound microenvironment, thereby enhancing the antibacterial activity of the hydrogel. The encapsulated Ant could serve as a pH monitor, sensitively indicating wound pH conditions in situ and indirectly reflecting wound infection. In vivo results in diabetic wound healing suggested that PGA/Ant/KTC/Cip hydrogel reduced inflammation and promoted angiogenesis and collagen deposition, thereby accelerating wound healing.

Electrospun Nanofiber Scaffolds Loaded with Metal-Based Nanoparticles for Wound Healing

Failures of wound healing have been a focus of research worldwide. With the continuous development of materials science, electrospun nanofiber scaffolds loaded with metal-based nanoparticles provide new ideas and methods for research into new tissue engineering materials due to their excellent antibacterial, anti-inflammatory, and wound healing abilities. In this review, the stages of extracellular matrix and wound healing, electrospun nanofiber scaffolds, metal-based nanoparticles, and metal-based nanoparticles supported by electrospun nanofiber scaffolds are reviewed, and their characteristics and applications are introduced. We discuss in detail the current research on wound healing of metal-based nanoparticles and electrospun nanofiber scaffolds loaded with metal-based nanoparticles, and we highlight the potential mechanisms and promising applications of these scaffolds for promoting wound healing.

State-of-the-Art Review of Advanced Electrospun Nanofiber Composites for Enhanced Wound Healing

Wound healing is a complex biological process with four main phases: hemostasis, inflammation, proliferation, and remodeling. Current treatments such as cotton and gauze may delay the wound healing process which gives a demand for more innovative treatments. Nanofibers are nanoparticles that resemble the extracellular matrix of the skin and have a large specific surface area, high porosity, good mechanical properties, controllable morphology, and size. Nanofibers are generated by electrospinning method that utilizes high electric force. Electrospinning device composed of high voltage power source, syringe that contains polymer solution, needle, and collector to collect nanofibers. Many polymers can be used in nanofiber that can be from natural or from synthetic origin. As such, electrospun nanofibers are potential scaffolds for wound healing applications. This review discusses the advanced electrospun nanofiber morphologies used in wound healing that is prepared by modified electrospinning techniques.

Recent Progress in Stimuli-Responsive Antimicrobial Electrospun Nanofibers

Electrospun nanofibrous membranes have garnered significant attention in antimicrobial applications, owing to their intricate three-dimensional network that confers an interconnected porous structure, high specific surface area, and tunable physicochemical properties, as well as their notable capacity for loading and sustained release of antimicrobial agents. Tailoring polymer or hybrid-based nanofibrous membranes with stimuli-responsive characteristics further enhances their versatility, enabling them to exhibit broad-spectrum or specific activity against diverse microorganisms. In this review, we elucidate the pivotal advancements achieved in the realm of stimuli-responsive antimicrobial electrospun nanofibers operating by light, temperature, pH, humidity, and electric field, among others. We provide a concise introduction to the strategies employed to design smart electrospun nanofibers with antimicrobial properties. The core section of our review spotlights recent progress in electrospun nanofiber-based systems triggered by single- and multi-stimuli. Within each stimulus category, we explore recent examples of nanofibers based on different polymers and antimicrobial agents. Finally, we delve into the constraints and future directions of stimuli-responsive nanofibrous materials, paving the way for their wider application spectrum and catalyzing progress toward industrial utilization.

Encapsulating Antibiotic and Protein-Stabilized Nanosilver into Sandwich-Structured Electrospun Nanofibrous Scaffolds for MRSA-Infected Wound Treatment

With the increasing prevalence of microbial infections, which results in prolonged inflammation and delayed wound healing, the development of effective and safe antimicrobial wound dressings of multiple properties remains challenging for public health. Despite their various formats, the available developed dressings with limited functions may not fulfill the diverse demands involved in the complex wound healing process. In this study, multifunctional sandwich-structured electrospinning nanofiber membranes (ENMs) were fabricated. According to the structural composition, the obtained ENMs included a hydrophilic inner layer loaded with curcumin and gentamicin sulfate, an antibacterial middle layer consisting of bovine serum albumin stabilized silver oxide nanoparticles, and a hydrophobic outer layer. The prepared sandwich-structured ENMs (SNM) exhibited good biocompatibility and killing efficacy on Escherichia coli, Staphylococcus aureus, and Methicillin-resistant S. aureus (MRSA). In particular, transcriptomic analysis revealed that SNM inactivated MRSA by inhibiting its carbohydrate and energy metabolism and reduced the bacterial resistance by downregulating mecA. In the animal experiment, SNM showed improved wound healing efficiency by reducing the bacterial load and inflammation. Moreover, 16S rDNA sequencing results indicated that SNM treatment may accelerate wound healing without observed influence on the normal skin flora. Therefore, the constructed sandwich-structured ENMs exhibited promising potential as dressings to deal with the infected wound management.

Multi-material electrospinning: from methods to biomedical applications

Electrospinning as a versatile, simple, and cost-effective method to engineer a variety of micro or nanofibrous materials, has contributed to significant developments in the biomedical field. However, the traditional electrospinning of single material only can produce homogeneous fibrous assemblies with limited functional properties, which oftentimes fails to meet the ever-increasing requirements of biomedical applications. Thus, multi-material electrospinning referring to engineering two or more kinds of materials, has been recently developed to enable the fabrication of diversified complex fibrous structures with advanced performance for greatly promoting biomedical development. This review firstly gives an overview of multi-material electrospinning modalities, with a highlight on their features and accessibility for constructing different complex fibrous structures. A perspective of how multi-material electrospinning opens up new opportunities for specific biomedical applications, i.e., tissue engineering and drug delivery, is also offered.

MXene-Embedded Electrospun Polymeric Nanofibers for Biomedical Applications: Recent Advances

Recently MXenes has gained immense attention as a new and exciting class of two-dimensional material. Due to their unique layered microstructure, the presence of various functional groups at the surface, earth abundance, and attractive electrical, optical, and thermal properties, MXenes are considered promising candidates for various applications such as energy, environmental, and biomedical. The ease of dispersibility and metallic conductivity of MXene render them promising candidates for use as fillers in polymer nanocomposites. MXene-polymer nanocomposites simultaneously benefit from the attractive properties of MXenes and the flexibility and facile processability of polymers. However, the potentiality of MXene to modify the electrospun nanofibers has been less studied. Understanding the interactions between polymeric nanofibers and MXenes is important to widen their role in biomedical applications. This review explores diverse methods of MXene synthesis, discusses our current knowledge of the various biological characteristics of MXene, and the synthesis of MXene incorporated polymeric nanofibers and their utilization in biomedical applications. The information discussed in this review serves to guide the future development and application of MXene-polymer nanofibers in biomedical fields.

PGS/Gelatin Nanocomposite Electrospun Wound Dressing

Infectious diabetic wounds can result in severe injuries or even death. Biocompatible wound dressings offer one of the best ways to treat these wounds, but creating a dressing with a suitable hydrophilicity and biodegradation rate can be challenging. To address this issue, we used the electrospinning method to create a wound dressing composed of poly(glycerol sebacate) (PGS) and gelatin (Gel). We dissolved the PGS and Gel in acetic acid (75 v/v%) and added EDC/NHS solution as a crosslinking agent. Our measurements revealed that the scaffolds' fiber diameter ranged from 180.2 to 370.6 nm, and all the scaffolds had porosity percentages above 70%, making them suitable for wound healing applications. Additionally, we observed a significant decrease (p < 0.05) in the contact angle from 110.8° ± 4.3° for PGS to 54.9° ± 2.1° for PGS/Gel scaffolds, indicating an improvement in hydrophilicity of the blend scaffold. Furthermore, our cell viability evaluations demonstrated a significant increase (p < 0.05) in cultured cell growth and proliferation on the scaffolds during the culture time. Our findings suggest that the PGS/Gel scaffold has potential for wound healing applications.

Biphasic drug release from electrospun structures

INTRODUCTION

Biphasic release, as a special drug-modified release profile that combines immediate and sustained release, allows fast therapeutic action and retains blood drug concentration for long periods. Electrospun nanofibers, particularly those with complex nanostructures produced by multi-fluid electrospinning processes, are potential novel biphasic drug delivery systems (DDSs).

AREAS COVERED

This review summarizes the most recent developments in electrospinning and related structures. In this review, the role of electrospun nanostructures in biphasic drug release was comprehensively explored. These electrospun nanostructures include monolithic nanofibers obtained through single-fluid blending electrospinning, core-shell and Janus nanostructures prepared via bifluid electrospinning, three-compartment nanostructures obtained via trifluid electrospinning, nanofibrous assemblies obtained through the layer-by-layer deposition of nanofibers, and the combined structure of electrospun nanofiber mats with casting films. The strategies and mechanisms through which complex structures facilitate biphasic release were analyzed.

EXPERT OPINION

Electrospun structures can provide many strategies for the development of biphasic drug release DDSs. However, many issues such as the scale-up productions of complex nanostructures, the in vivo verification of the biphasic release effects, keeping pace with the developments of multi-fluid electrospinning, drawing support from the state-of-the-art pharmaceutical excipients, and the combination with traditional pharmaceutical methods need to be addressed for real applications.

Effect of Size, Shape and Surface Functionalization on the Antibacterial Activity of Silver Nanoparticles

Silver nanoparticles (AgNPs) are the most investigated antibacterial agents against multidrug resistant (MDR) pathogens. They can lead to cellular death by means of different mechanisms, damaging several cell compartments, from the external membrane, to enzymes, DNA and proteins; this simultaneous attack amplifies the toxic effect on bacteria with respect to traditional antibiotics. The effectiveness of AgNPs against MDR bacteria is strongly correlated with their chemical and morphological properties, which influence the pathways involved in cellular damage. In this review, AgNPs' size, shape and modification by functional groups or other materials are reported, both to investigate the different synthetic pathways correlated with nanoparticles' modifications and to evaluate the related effect on their antibacterial activity. Indeed, understanding the synthetic conditions for obtaining performing antibacterial AgNPs could help to tailor new and improved silver-based agents to combat multidrug resistance.

Electrospun UV-cross-linked polyvinylpyrrolidone fibers modified with polycaprolactone/polyethersulfone microspheres for drug delivery

Electrospun fibers, often used as drug delivery systems, have two drawbacks - in the first stage of their action a sudden active substance burst release occurs and they have a relatively small capacity for a drug. In this work the fibers are modified by the addition of drug-loaded microspheres acting as micro-containers for the drug and increasing the total drug capacity of the system. Its release from such a structure is slowed down by placing the microspheres inside the fibers so they are covered with an outer layer of fiber-forming polymer. The work presents a new method (microsphere suspension electrospinning) of obtaining polyvinylpyrrolidone fibers cross-linked with UV light modified with polycaprolactone/polyethersulphone microspheres loaded with active substance - rhodamine 640 as a marker or ampicillin as a drug example. The influence of UV-cross-linking time and the microspheres addition on the degradation, mechanical strength and transport properties of fibrous mats was investigated. The mats were insoluble in water, in some cases mechanically stronger, their drug capacity was increased and the burst effect was eliminated. The antibacterial properties of ampicillin-loaded mats were confirmed. The product of proposed suspension electrospinning process has application potential as a drug delivery system.

Nanofibers in Ocular Drug Targeting and Tissue Engineering: Their Importance, Advantages, Advances, and Future Perspectives

Nanofibers are frequently encountered in daily life as a modern material with a wide range of applications. The important advantages of production techniques, such as being easy, cost effective, and industrially applicable are important factors in the preference for nanofibers. Nanofibers, which have a broad scope of use in the field of health, are preferred both in drug delivery systems and tissue engineering. Due to the biocompatible materials used in their construction, they are also frequently preferred in ocular applications. The fact that they have a long drug release time as a drug delivery system and have been used in corneal tissue studies, which have been successfully developed in tissue engineering, stand out as important advantages of nanofibers. This review examines nanofibers, their production techniques and general information, nanofiber-based ocular drug delivery systems, and tissue engineering concepts in detail.

Optimal delivery of poorly soluble drugs using electrospun nanofiber technology: Challenges, state of the art, and future directions

Poor aqueous solubility of both, existing drug molecules and those which are currently in the developmental stage, have posed a great challenge to pharmaceutical scientists because they often exhibit poor dissolution behavior and subsequent poor and erratic bioavailability. This has triggered extensive research to explore nanotechnology-based technology platforms for possible rescue. Recently, nanofibers have been exploited widely for diverse biomedical applications including for drug delivery. Electrospun nanofibers are capable of preserving the homogeneously loaded therapeutic agents in amorphous state potentialy impairing devitrification. The present review aims at providing an overview of the various key factors that affect the electrospinning process and characteristics of the nanofibers while fabrication of drug loaded nanofibers for poorly soluble drug candidates. The review explores various methodological advancements in the electrospinning process and set-ups for production scale-up. The various types of electrospun nanofibers (like simple matrix, core-sheath, Janus, and inclusion complex nanofibers) that have been exploited for the delivery of poorly soluble drugs are also critically assessed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Quarternized chitosan/quercetin/polyacrylamide semi-interpenetrating network hydrogel with recoverability, toughness and antibacterial properties for wound healing

Antibiotic abuse has posed enormous burdens on patients and healthcare systems. Hence, the design and development of non-antibiotic wound dressings to meet clinical demand are urgently desired. However, there remains one of the impediments to hydrogel wound dressings that integrated with good recoverability, toughness, and excellent antibacterial properties. Herein, a series of semi-interpenetrating network (semi-IPN) hydrogels with exceptional mechanical performance and remarkable antibacterial activity based on quaternized chitosan (QCS) and polyacrylamide (PAM) were developed using a one-pot method. Additionally, the antibacterial activity of semi-IPN hydrogel against S. aureus and E. coli was enhanced by integrating it with quercetin (QT). The semi-IPN hydrogels also exhibited high recoverability and toughness, outstanding liquid absorbability (the swelling ratio reached 565 ± 12 %), and a satisfying water vapor transmission rate. Moreover, the semi-IPN hydrogels presented ideal hemocompatibility and cytocompatibility. These high-elastic hydrogels are promising candidates for potential applications in wound dressing, tissue repair, chronic wound care, as well as other biomedical fields.

PCL/Gelatin/Graphene Oxide Electrospun Nanofibers: Effect of Surface Functionalization on In Vitro and Antibacterial Response

The emergence of resistance to pathogenic bacteria has resulted from the misuse of antibiotics used in wound treatment. Therefore, nanomaterial-based agents can be used to overcome these limitations. In this study, polycaprolactone (PCL)/gelatin/graphene oxide electrospun nanofibers (PGO) are functionalized via plasma treatment with the monomeric groups diallylamine (PGO-M1), acrylic acid (PGO-M2), and tert-butyl acrylate (PGO-M3) to enhance the action against bacteria cells. The surface functionalization influences the morphology, surface wettability, mechanical properties, and thermal stability of PGO nanofibers. PGO-M1 and PGO-M2 exhibit good antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas PGO-M3 tends to reduce their antibacterial properties compared to PGO nanofibers. The highest proportion of dead bacteria cells is found on the surface of hydrophilic PGO-M1, whereas live cells are colonized on the surface of hydrophobic PGO-M3. Likewise, PGO-M1 shows a good interaction with L929, which is confirmed by the high levels of adhesion and proliferation with respect to the control. All the results confirm that surface functionalization can be strategically used as a tool to engineer PGO nanofibers with controlled antibacterial properties for the fabrication of highly versatile devices suitable for different applications (e.g., health, environmental pollution).

Recent Progress of Electrospun Herbal Medicine Nanofibers

Herbal medicine has a long history of medical efficacy with low toxicity, side effects and good biocompatibility. However, the bioavailability of the extract of raw herbs and bioactive compounds is poor because of their low water solubility. In order to overcome the solubility issues, electrospinning technology can offer a delivery alternative to resolve them. The electrospun fibers have the advantages of high specific surface area, high porosity, excellent mechanical strength and flexible structures. At the same time, various natural and synthetic polymer-bound fibers can mimic extracellular matrix applications in different medical fields. In this paper, the development of electrospinning technology and polymers used for incorporating herbal medicine into electrospun nanofibers are reviewed. Finally, the recent progress of the applications of these herbal medicine nanofibers in biomedical (drug delivery, wound dressing, tissue engineering) and food fields along with their future prospects is discussed.

Synthesis and characterization of Ag-decorated litchi-like porous Cu/Cu2O micro/nanoparticles with antibacterial activity

Efficient and stable inorganic antibacterial material is highly spotted in antibacterial materials. However, the morphology and grain diameter of conventional inorganic compound antibacterial agent carrier are difficult to control and severely deteriorate antibacterial properties. In this research, using diethylene glycol monomer methyl ether as a pore-forming agent, litchi-like porous micro/nano Cu/Cu₂O composite antibacterial carriers (Car-MNps) with good dispersion and high crystallinity are prepared by a liquid-phase chemical reduction process. Subsequently, we develop a synergistic system of inorganic composite antibacterial materials decorated with silver (Ag/Car-MNps). The microstructures of the antibacterial materials are characterized by means of various techniques, such as X-ray diffraction, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy, and nitrogen adsorption. The antibacterial activities are evaluated by methods of bacteriostatic zone and minimum inhibitory concentration (MIC). The results show that the micro- and nano-materials of Car-MNPs exhibit high specific surface area characteristics and show attractive bactericidal properties. The MIC values of Ag/Car-MNps against S. aureus and E. coli decrease from 1000 mg/L and 2000mg/L to 125 and 250 mg/L, respectively, in comparison with those of Car-MNps. Our experiments may show novel insights for the development of inorganic compound antibacterial agents.

Electrospun fibers as carriers for topical drug delivery and release in skin bandages and patches for atopic dermatitis treatment

The skin is a complex layer system and the most important barrier between the environment and the organism. In this review, we describe some widespread skin problems, with a focus on eczema, which are affecting more and more people all over the world. Most of treatment methods for atopic dermatitis (AD) are focused on increasing skin moisture and protecting from bacterial infection and external irritation. Topical and transdermal treatments have specific requirements for drug delivery. Breathability, flexibility, good mechanical properties, biocompatibility, and efficacy are important for the patches used for skin. Up to today, electrospun fibers are mostly used for wound dressing. Their properties, however, meet the requirements for skin patches for the treatment of AD. Active agents can be incorporated into fibers by blending, coaxial or side-by-side electrospinning, and also by physical absorption post-processing. Drug release from the electrospun membranes is affected by drug and polymer properties and the technique used to combine them into the patch. We describe in detail the in vitro release mechanisms, parameters affecting the drug transport, and their kinetics, including theoretical approaches. In addition, we present the current research on skin patch design. This review summarizes the current extensive know-how on electrospun fibers as skin drug delivery systems, while underlining the advantages in their prospective use as patches for atopic dermatitis. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Emerging Technologies.

The fabrication and evaluation of silver nanoparticle-based keratin scaffolds

The biotoxicity caused by focus releasing of Ag, which associated with the Ag loading mode, is a problematic issue that need to be solved for practical utilization of the keratin based wound dressing. In this study, keratin/AgNPs blend scaffolds (Ker/Ag) and keratin scaffolds with AgNPs attached on the scaffold's wall surface (Ag@Ker) were prepared. Structure and physical properties of the scaffolds were tested and investigated. In comparison to the Ag@Ker scaffolds, the Ker/Ag scaffolds with uniform dispersion of AgNPs have larger tensile strength and slower degradation rate. Both kind of scaffolds present excellent antibacterial property with 10 μg mL^-1 AgNPs addition, while the Ker/Ag displayed a linear Ag releasing ratio in the first 5-7 days, which is beneficial for obtaining a continuous antibacterial property and avoiding the biotoxicity caused by focus release of Ag. Correspondingly, cytotoxicity assay further reveals that the continuously slow release of Ag of the Ker/Ag scaffolds accelerated the proliferation of cell. Infectious animal models and histological studies showed that the Ker/Ag scaffolds can effectively inhibit the inflammatory response and accelerate epithelialization. Thus, it can be concluded that the Ker/Ag scaffolds with uniform dispersion of AgNPs are more attractive as wound repair materials.

Progress of Electrospun Nanofibrous Carriers for Modifications to Drug Release Profiles

Electrospinning is an advanced technology for the preparation of drug-carrying nanofibers that has demonstrated great advantages in the biomedical field. Electrospun nanofiber membranes are widely used in the field of drug administration due to their advantages such as their large specific surface area and similarity to the extracellular matrix. Different electrospinning technologies can be used to prepare nanofibers of different structures, such as those with a monolithic structure, a core-shell structure, a Janus structure, or a porous structure. It is also possible to prepare nanofibers with different controlled-release functions, such as sustained release, delayed release, biphasic release, and targeted release. This paper elaborates on the preparation of drug-loaded nanofibers using various electrospinning technologies and concludes the mechanisms behind the controlled release of drugs.

Single Step Assembly of Janus Porous Biomaterial by Sub-Ambient Temperature Electrodeposition

Janus porous biomaterials are gaining increasing attention and there are considerable efforts to develop simple, rapid, and scalable methods capable of tuning micro- and macro-structures. Here, a single-step electro-fabrication method to create a Janus porous film by the electrodeposition of the amino-polysaccharide chitosan is reported. Specifically, a Janus structure emerges spontaneously when electrodeposition is performed at sub-ambient temperature (0-5 °C). Sub-ambient temperature electrodeposition experiments show that: a Janus microstructure emerges (potentially as the result of a subtle alteration of the intermolecular interactions responsible for self-assembly); important microstructural features (pore size, porosity, and thicknesses) can be tuned by conditions; and this method is readily scalable (vs serial printing) and can yield complex tubular structures with Janus faces. In vitro studies demonstrate anisotropic cell guidance, and in vivo studies using a rat calvarial defect model further confirm the beneficial features of such Janus porous film for guided bone regeneration. In summary, these results further demonstrate that electro-fabrication provides a simple and scalable platform technology for the controlled functional structures of soft matter for applications in regenerative medicine.

Electrospun hybrid nanofibers: Fabrication, characterization, and biomedical applications

Nanotechnology is one of the most promising technologies available today, holding tremendous potential for biomedical and healthcare applications. In this field, there is an increasing interest in the use of polymeric micro/nanofibers for the construction of biomedical structures. Due to its potential applications in various fields like pharmaceutics and biomedicine, the electrospinning process has gained considerable attention for producing nano-sized fibers. Electrospun nanofiber membranes have been used in drug delivery, controlled drug release, regenerative medicine, tissue engineering, biosensing, stent coating, implants, cosmetics, facial masks, and theranostics. Various natural and synthetic polymers have been successfully electrospun into ultrafine fibers. Although biopolymers demonstrate exciting properties such as good biocompatibility, non-toxicity, and biodegradability, they possess poor mechanical properties. Hybrid nanofibers from bio and synthetic nanofibers combine the characteristics of biopolymers with those of synthetic polymers, such as high mechanical strength and stability. In addition, a variety of functional agents, such as nanoparticles and biomolecules, can be incorporated into nanofibers to create multifunctional hybrid nanofibers. Due to the remarkable properties of hybrid nanofibers, the latest research on the unique properties of hybrid nanofibers is highlighted in this study. Moreover, various established hybrid nanofiber fabrication techniques, especially the electrospinning-based methods, as well as emerging strategies for the characterization of hybrid nanofibers, are summarized. Finally, the development and application of electrospun hybrid nanofibers in biomedical applications are discussed.

Advanced functional nanofibers: strategies to improve performance and expand functions

Nanofibers have a wide range of applications in many fields such as energy generation and storage, environmental sensing and treatment, biomedical and health, thanks to their large specific surface area, excellent flexibility, and superior mechanical properties. With the expansion of application fields and the upgrade of application requirements, there is an inevitable trend of improving the performance and functions of nanofibers. Over the past few decades, numerous studies have demonstrated how nanofibers can be adapted to more complex needs through modifications of their structures, materials, and assembly. Thus, it is necessary to systematically review the field of nanofibers in which new ideas and technologies are emerging. Here we summarize the recent advanced strategies to improve the performances and expand the functions of nanofibers. We first introduce the common methods of preparing nanofibers, then summarize the advances in the field of nanofibers, especially up-to-date strategies for further enhancing their functionalities. We classify these strategies into three categories: design of nanofiber structures, tuning of nanofiber materials, and improvement of nanofibers assemblies. Finally, the optimization methods, materials, application areas, and fabrication methods are summarized, and existing challenges and future research directions are discussed. We hope this review can provide useful guidance for subsequent related work.

Graphical abstract