Development and In Vitro Analysis of Layer-by-Layer Assembled Membranes for Potential Wound Dressing: Electrospun Curcumin/Gelatin as Middle Layer and Gentamicin/Polyvinyl Alcohol as Outer Layers

Electrospun fiber patches for inflammatory skin diseases - Correlating in vitro drug release with ex vivo permeation

In this proof-of-concept study, we aimed to develop an anti-inflammatory patch that in contrast to the semi-solid standard therapy is dry and non-greasy, and only needs to be changed once a day due to continuous release of the active ingredient over 24 h. While fiber materials for the treatment of inflammatory skin diseases have been reported in the literature, the majority of studies focuses solely on material characterization including in vitro release studies; however, there is a lack of ex vivo permeation studies as well as comparison with standard therapy. However, such experiments are crucial to deduct the potential efficacy of the drug delivery system, as skin absorption of the drug may be the rate-limiting step and not the drug release. Therefore, we set out to investigate different types of electrospun fiber systems based on polycaprolactone, a polymer with a well-established safety profile widely used for fabricating electrospun patches. The electrospun fiber patches were loaded with the anti-inflammatory drug hydrocortisone and characterized not only for their drug release properties, but for the first time also for their skin permeation and retention as well as their cytocompatibility and anti-inflammatory properties on human skin. While in the release studies, the layer-by-layer fiber system proved to be best suited for an application time of 24 h, this was not reflected in the permeation studies, where all fiber systems showed a similar skin permeation and retention of the drug. In our study set-up, a comparison with standard cream formulations revealed that electrospun fibers offer an advantage in terms of the permeated amount of hydrocortisone. Overall, this study supports the importance of conducting comparisons with standard therapies and, additionally, confirms that electrospun fibers are a promising dosage form for the controlled release of anti-inflammatory drugs for the treatment of inflammatory skin diseases.

Flow Dynamics through a High Swelling Nanofiber Membrane Processed at Different Relative Humidities: A Study on a FexOy/Polyvinyl Alcohol Composite

Addressing the global problem of polluted water requires sustainable, efficient, and scalable remediation solutions, such as electrospun polyvinyl alcohol (PVA) membranes incorporating specific nanoadsorbents. The retention of contaminants depends on membrane swelling, morphology, and the adsorbent within the nanofiber. This study investigated the effect of relative humidity (RH) within the electrospinning chamber on the morphology of the resulting mats and how this affected the flow dynamics depending on whether or not the permeating liquid induced swelling in the membranes. An insolubilized PVA membrane was used as a hydrophilic filter model and a PVA membrane filled with iron oxide nanoparticles (IONPs) as a composite model (PVA + IONPs). The presence of IONPs increases the nanofiber diameter, which decreases when prepared under intermediate RH (IRH). Consequently, the nanofiber configuration, which is critical for filtration tortuosity, is influenced by RH. The initial swelling results in over 60% greater water flux through PVA + IONPs compared to PVA at an equivalent RH. This characterization helps to optimize membrane applications, highlighting that PVA + IONPs exhibit lower permeability values at IRH, indicating improved contaminant retention capabilities.

Polymer-Based Wound Dressings Loaded with Essential Oil for the Treatment of Wounds: A Review

Wound healing can result in complex problems, and discovering an effective method to improve the healing process is essential. Polymeric biomaterials have structures similar to those identified in the extracellular matrix of the tissue to be regenerated and also avoid chronic inflammation, and immunological reactions. To obtain smart and effective dressings, bioactive agents, such as essential oils, are also used to promote a wide range of biological properties, which can accelerate the healing process. Therefore, we intend to explore advances in the potential for applying hybrid materials in wound healing. For this, fifty scientific articles dated from 2010 to 2023 were investigated using the Web of Science, Scopus, Science Direct, and PubMed databases. The principles of the healing process, use of polymers, type and properties of essential oils and processing techniques, and characteristics of dressings were identified. Thus, the plants Syzygium romanticum or Eugenia caryophyllata, Origanum vulgare, and Cinnamomum zeylanicum present prospects for application in clinical trials due to their proven effects on wound healing and reducing the incidence of inflammatory cells in the site of injury. The antimicrobial effect of essential oils is mainly due to polyphenols and terpenes such as eugenol, cinnamaldehyde, carvacrol, and thymol.

Designing an antimicrobial film for wound applications incorporating bacteriophages and ε-poly-l-lysine

Alginate-based dressings have been shown to promote wound healing, leveraging the unique properties of alginate. This work aimed to develop and characterize flexible individual and bilayered films to deliver bacteriophages (phages) and ε-Poly-l-lysine (ε-PLL). Films varied in different properties. The moisture content, swelling and solubility increased with higher alginate concentrations. The water vapour permeability, crucial in biomedical films to balance moisture levels for effective wound healing, reached optimal levels in bilayer films, indicating these will be able to sustain an ideal moist environment. The bilayer films showed improved ductility (lower tensile strength and increased elongation at break) compared to individual films. The incorporated phages maintained viability for 12 weeks under vacuum and refrigerated conditions, and their release was sustained and gradual. Antibacterial immersion tests showed that films with phages and ε-PLL significantly inhibited Pseudomonas aeruginosa PAO1 growth (>3.1 Log CFU/cm2). Particle release was influenced by the swelling degree and diffusional processes within the polymer network, providing insights into controlled release mechanisms for particles of varying size (50 nm to 6 μm) and charge. The films developed, demonstrated modulated release capabilities for active agents, and may show potential as controlled delivery systems for phages and wound healing adjuvants.

Hybrid-Aligned Fibers of Electrospun Gelatin with Antibiotic and Polycaprolactone Composite Membranes as an In Vitro Drug Delivery System to Assess the Potential Repair Capacity of Damaged Cornea

The cornea lacks the ability to repair itself and must rely on transplantation to repair damaged tissue. Therefore, creating alternative therapies using dressing membranes based on tissue engineering concepts to repair corneal damage before failure has become a major research goal. Themost outstanding features that are important in reconstructing a damaged cornea are the mechanical strength and transparency of the membrane, which are the most important standard considerations. In addition, preventing infection is an important issue, especially in corneal endothelial healing processes. The purpose of this study was to produce aligned fibers via electrospinning technology using gelatin (Gel) composite polycaprolactone (PCL) as an optimal transport and antibiotic release membrane. The aim of the composite membrane is to achieve good tenacity, transparency, antibacterial properties, and in vitro biocompatibility. Results showed that the Gel and PCL composite membranes with the same electrospinning flow rate had the best transparency. The Gel impregnated with gentamicin antibiotic in composite membranes subsequently exhibited transparency and enhanced mechanical properties provided by PCL and could sustainably release the antibiotic for 48 h, achieving good antibacterial effects without causing cytotoxicity. This newly developed membrane has the advantage of preventing epidermal tissue infection during clinical operations and is expected to be used in the reconstruction of damaged cornea in the future.