Esra Karaca

Burn wounds present significant clinical challenges due to high infection risk, delayed healing, and extensive tissue damage. The development of biomimetic skin substitutes capable of simultaneously supporting tissue regeneration and preventing infection remains a critical need in burn wound management. In this study, a novel ceragenin (CSA‐44)‐loaded tri‐layered skin substitute was developed to mimic the epidermis, dermis, and hypodermis and address both wound healing and infection prevention simultaneously. The substitute comprised a poly( ε ‐caprolactone) (PCL) film as the upper layer, polyvinyl alcohol (PVA)/sodium alginate (SA)‐PCL nanofibers as the middle layer, and a CSA‐44‐loaded PVA/Gelatin (Gel) hydrogel as the bottom layer. The tri‐layered scaffold exhibited a hierarchical porous architecture, high swelling capacity (557.75% ± 52.87%), controlled degradation behavior, and a water vapor transmission rate of 2514.92 ± 63.41 g/m ² /day, indicating suitability for maintaining a moist wound environment. Drug release studies demonstrated controlled CSA‐44 delivery, with 92.26% ± 6.90% cumulative release after 180 min. The scaffold exhibited strong antibacterial activity against Escherichia coli , Pseudomonas aeruginosa , Staphylococcus aureus , and methicillin‐resistant S. aureus (MRSA), with complete inhibition observed within minutes. Cytocompatibility studies using human keratinocyte (HaCaT) cells demonstrated that the ceragenin‐loaded scaffold maintained acceptable cell viability within the tested concentration range. In addition, co‐culture experiments with HaCaT and human umbilical vein endothelial (HUVEC) cells revealed enhanced endothelial tube formation, suggesting a favorable microenvironment for angiogenic signaling. The results suggested that the ceragenin‐loaded tri‐layered skin substitute holds promise as a multifunctional biomaterial for burn wound management by combining antimicrobial efficacy and tissue regeneration capability.

Essential oils are natural insect repellents, which can be microencapsulated and protected by wall materials to provide prolonged protection against insects. The protection and release of these repellents depend on various parameters, including morphology and production conditions. Herein, twenty-seven gum arabic/citronella essential oil (GA/CEO) spray-dried microcapsules were produced by using three wall-to-core ratios (3:1, 4:1, 6:1), three inlet temperatures (120, 150, 180 °C), and three feed rates (1, 2.5, 5 mL/min). The morphology, particle size, encapsulation efficiency, and release rates were evaluated. The insect repellent activity of microcapsules (0.25, 0.5, and 1 g) against Drosophila melanogaster flies was tested. A systematic process optimization was carried out by evaluating the effects of both emulsion concentration and process parameters on the release rates. Microcapsules with smooth surfaces and homogeneous particle sizes were produced. Encapsulation efficiency reached 90% by increasing the inlet temperature and feed rate. Slower release rates (approximately 40%) were achieved with higher concentrations of the wall material and temperatures, generally. Optimal process conditions were determined as a wall-to-core ratio of 4:1, temperatures exceeding 150 °C, and feed rates above 2.5 mL/min. The highest repellent activity achieved was 95%, indicating effectiveness of GA/CEO microcapsules as insect repellent materials.

Integration of essential oils into nanofibers not only enhances the bioactivity of these substances but also offers greener solutions for many applications including protective textiles and coatings. Herein, citronella or thyme oil-loaded polyurethane nanofibers were fabricated via blend electrospinning, and their release behavior was evaluated. Initially, polyurethane nanofibers with different citronella or thyme oil concentrations (5%, 10%, and 15%) and spinning parameters (tip-to-collector distance: 15–20 cm, voltage: 15–20 kV) were fabricated. The nanofiber mats were characterized in terms of surface morphology, wettability, and porosity. Afterward, the release behaviors of the selected mats were examined. Depending on the oil concentration and spinning parameters, nanofibers with diameters in the range of 175–442 nm were produced. The incorporation of essential oil increased contact angles from 102° to 125°, while the bulk porosities were decreased from ⁓76% to ⁓58%, depending on the oil. Fourier-transform infrared spectroscopy analysis validated successful essential oil integration. The release studies revealed that thyme oil exhibited a release of ∼10% and citronella essential oil ∼5% over 18 h, indicating a controlled and sustained release. This study demonstrates the potential of essential oil-loaded polyurethane nanofibers as eco-friendly materials for protective textiles and coatings.

Herein, composite films were produced by incorporating different amounts (1, 3, 5, and 7%) of barium titanate nanoparticles into the thermoplastic polyurethane matrix using a solution casting method. This study examined the impact of the presence and concentration of a barium titanate additive on morphologic properties, mechanical performance, thermal stability, solar behavior, and wettability of produced film samples. The films were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, scanning electron microscope, ultraviolet-visible near-infrared spectrophotometer, water contact angle, and tensile strength measurements. In the present study, the mass loss of samples containing 7% barium titanate was 24% lower than that of the pure polyurethane reference. The increase of barium titanate rate added to polyurethane enhanced the solar reflectance property of the films, including the near-infrared region. As a prominent result, the transmittance value decreased significantly compared to the reference in the ultraviolet region, and it dropped to 3% for the highest additive concentration. The contact angle values of polyurethane films increased by 11–40% depending on the barium titanate addition ratio. The nano additive also positively affected the mechanical performance of the reference polyurethane film by slightly increasing the tensile strength values.

In this study, a nanofiber surface loaded with apheresis platelet concentrate (APC) was produced for the first time to develop a bioactive wound dressing design. Nanofiber surface (n=5) consisting of polyurethane polymer outer layer, polyvinyl alcohol polymer middle layer, and polycaprolactone polymer matrix inner layer were produced via the electrospinning method. The surface morphologies of the produced nanofiber surfaces were examined by scanning electron microscopy. Quantitative analyzes of growth factors released from the APC-loaded composite nanofiber surfaces into phosphate-buffered saline at certain time intervals were performed with the ELISA. When the release amounts between bFGF, EGF, and PDGF-AA groups were compared, a significant difference was found in all periods (p0.05), but there was a significant difference between the EGF and PDGF-AA growth factors (p

This study aimed to prepare a polyvinyl alcohol/sodium alginate (PVSA) nanofibrous mat as an amoxicillin (AMOX) delivery system. AMOX was loaded to the PVSA nanofibers during electrospinning, and the AMOX-loaded PVSA (PVSA/AMOX) nanofibrous mat was cross-linked by glutaraldehyde (GA). The PVSA/AMOX nanofibrous mat was characterized by Fourier Transform infrared spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller, and mercury porosimetry analyses. The thickness, air permeability, and water vapor transmission rate of the PVSA/AMOX nanofibrous mat were 0.43 ± 0.08 mm, 17.2 ± 4.91 L/m²/s, and 1485 ± 13.6 g/m²/d, respectively, which were suitable for wound dressing applications. The tensile strength was 6.73 ± 0.48 MPa and elongation at a maximum load was 81.9 ± 17.0%, within the ranges of human skin’s values. The total porosity was 59.4%, enabling cell adhesion, migration, and proliferation. The PVSA/AMOX nanofibrous mat has high swelling (319 ± 4.2%) and low degradation (2.2 ± 0.1% in 10 days) ratios. The nanofibrous mat cross-linked with 0.25% GA solution for 20 min had a 73.07% cumulative release for 90 min. The drug release kinetics were obeyed to the Korsmeyer-Peppas model. The nanofibrous mat presented antibacterial activity on S. aureus ATCC 29213 and E. coli ATCC 25922, and there was no cytotoxic effect on the human normal keratinocyte cells, demonstrating the potential for use in wound dressing applications.