A Straightforward Approach towards Antibacterial and Anti-Inflammatory Multifunctional Nanofiber Membranes with Sustained Drug Release Profiles

Fabrication and evaluation of a bi-layered electrospun PCL/PVA patch for wound healing: Release of vitamins and silver nanoparticle

There is still little research on the co-delivery of vitamins and AgNPs to accelerate wound healing. In this study, a bi-layered electrospun PCL/PVA patch loaded with Vitamin C, Vitamin B12, and AgNPs was fabricated using a co-spinning technique. SEM, FTIR, degradation, swelling, tensile strength, disk diffusion, and MTT assay were studied. Nine rats were placed in three groups (control: no treatment, G1: without agents, and G2: with agents) for 14 days in an in-vivo study. H&E and Masson Trichrome staining were employed for histological analysis. Results showed that the final electrospun wound dressings depicted nanofibers with diameters ranging from 100 to 500 nm. The presence of AgNP enhanced the mechanical strength (40-50 MPs). An appropriate swelling (100 %) and degradation (50 %) rate was observed for groups with no significant difference (P > 0.05). G1 and G2 did not show a significant difference in terms of porosity (65 % vs. 69 %). Regarding WVTR, G2 demonstrated higher WVTR (88 vs. 95 g/m2. h). G2 showed a vitamin release of more than 90 % after 48 h. Compared to G1, G2 demonstrated good antibacterial activity (>3 cm) against E. Coli and S. aureous (P < 0.01), with cell viability of more than 93 % (P > 0.05). Furthermore, the in-vivo study approved that G2 accelerated wound healing in full-thickness wounds, compared to the control groups, with notable wound size reduction (8 mm), epithelialization, and collagen formation. The findings support the use of this simple but potent electrospun wound dressing for the healing of full-thickness wounds.

Multifunctional Drug- and AuNRs-Loaded ROS-Responsive Selenium-Containing Polyurethane Nanofibers for Smart Wound Healing

Elevated levels of ROS, bacterial infection, inflammation, and improper regeneration are the factors that need to be addressed simultaneously for achieving effective wound healing without scar formation. This study focuses on the fabrication of electrospun ROS-responsive selenium-containing polyurethane nanofibers incorporating deferoxamine mesylate (Def), indomethacin (Indo), and gold nanorods (AuNRs) as proangiogenesis, anti-inflammatory, and antibacterial agents for synchronized delivery to a full-thickness wound in vivo. The structure of the fabricated nanofibers was analyzed by various techniques. Toxicity was checked by CCK-8 and hemolytic assays. The efficiency of wound healing in vitro was verified by a transwell assay and cell scratch assay. The wound healing efficiency of the nanofibers was assayed in full-thickness wounds in a rat model. The multifunctional nanofibers had a porous structure, enhanced antioxidation, antibacterial activity, and promoted wound healing. They eradicated TNF-α and IL-6, increased IL-10 expression, and revealed the angiogenic potential by increased expression of HIF-1α, VEGF, and CD31.

Exudate-Induced Gelatinizable Nanofiber Membrane with High Exudate Absorption and Super Bactericidal Capacity for Bacteria-Infected Wound Management

Invasion of bacteria and continuous oozing of exudate are significant causes of interference with the healing of infected wounds. Therefore, an exudate-induced gelatinizable and near-infrared (NIR)-responsive nanofiber membrane composed of polyvinyl alcohol (PVA), carboxymethyl chitosan (CMC), and Fe-doped phosphomolybdic acid (Fe-PMA) with exceptional exudate absorption capacity and potent bactericidal efficacy is developed and denoted as the PVA-FP-CMC membrane. After absorbing exudate, the fiber membrane can transform into a hydrogel membrane, forming coordination bonds between the Fe-PMA and CMC. The unique exudate-induced gelation process imparts the membrane with high exudate absorption and retention capability, and the formed hydrogel also traps the bacteria that thrive in the exudate. Moreover, it is discovered for the first time that the Fe-PMA exhibits an enhanced photothermal conversion capability and photocatalytic activity compared to the PMA. Therefore, the presence of Fe-PMA provides the membrane with a photothermal and photodynamic therapeutic effect for killing bacteria. The PVA-FP-CMC membrane is proven with a liquid absorption ratio of 520.7%, a light-heat conversion efficiency of 41.9%, high-level generation of hydroxyl radical (•OH) and singlet oxygen (1O2), and a bacterial killing ratio of 100% for S. aureus and 99.6% for E. coli. The treatment of infected wounds on the backs of rats further confirms the promotion of wound healing by the PVA-FP-CMC membrane with NIR irradiation. Overall, this novel functional dressing for the synergistic management of bacteria-infected wounds presents a promising therapeutic strategy for tissue repair and regeneration.

Electrospun fibers for the treatment of skin diseases

Skin diseases are among the most common diseases in the global population and with the growth of the aging population, they represent an increasing burden to healthcare systems worldwide. Even though they are rarely life-threatening, the suffering for those affected is high due to the visibility and physical discomfort related to these diseases. Typical symptoms of skin diseases include an inflamed, swollen or itchy skin, and therefore, there is a high demand for effective therapy options. In recent years, electrospinning has attracted considerable interest in the field of drug delivery. The technique allows producing multifunctional drug-loaded fibrous patches from various natural and synthetic polymers with fiber diameters in the nano- and micrometer range, suitable for the treatment of a wide variety of skin diseases. The great potential of electrospun fiber patches not only lies in their tunable drug release properties and the possibility to entrap a variety of therapeutic compounds, but they also provide physical and mechanical protection to the impaired skin area, exhibit a high surface area, allow gas exchange, absorb exudate due to their porous structure and are cytocompatible and biodegradable. In the case of wound healing, cell adhesion is promoted due to the resemblance of the electrospun fibers to the structure of the native extracellular matrix. This review gives an overview of the potential applications of electrospun fibers in skin therapy. In addition to the treatment of bacterial, diabetic and burn wounds, focus is placed on inflammatory diseases such as atopic dermatitis and psoriasis, and therapeutic options for the treatment of skin cancer, acne vulgaris and herpes labialis are discussed. While we aim to emphasize the great potential of electrospun fiber patches for the treatment of skin diseases with this review paper, we also highlight challenges and limitations of current research in the field.

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.