Wound dressings have experienced continuous and significant changes since the ancient times. The development starts with the use of natural materials to simply cover the wounds to the materials of the present time that could be specially made to exhibit various extraordinary functions. The modern bandage materials made of electrospun biopolymers contain various active compounds that are beneficial to the healing of wounds. These materials are fibrous in nature, with the size of fibers segments ranging from tens of nanometers to micrometers. With the right choices of biopolymers used for these fibrous materials, they could enhance the healing of wounds significantly compared with the conventional fibrous dressing materials, such as gauze. These bandages could be made such that they contain bioactive ingredients, such as antimicrobial, antibacterial, and antiinflammatory agents, which could be released to the wounds enhancing their healing. In an active wound dressing (AWD), the main purpose is to control the biochemical states of a wound in order to aid its healing process. This review provides an overview of different types of wounds, effective parameters in wound healing and different types of wound dressing materials with a special emphasis paid to those prepared by electrospinning.

The use of herbal drugs as biocompatible and nontoxic drugs without special side effects in wound dressings are highly favored compared to that of chemical and synthetic drugs. In this study, the properties and performance of electrospun poly(ε‐caprolactone) (PCL), poly(lactic acid) (PLA), and their 50/50 hybrid nanofibrous mats containing the herbal drug thymol (1.2% v/v) as wound dressings were investigated. The optimized solution concentrations of PCL (12% w/v) and PLA (3% w/v) in chloroform/dimethylformamide (7:3) for electrospinning were determined with viscometry and scanning electron microscopy studies to obtain smooth and beadless nanofibers. The results of the drug‐release behavior along with swelling tests showed that the electrospun 50/50 PCL/PLA hybrid nanofibers had the highest level of drug release (∼ 72%) compared with the PCL and PLA nanofibrous samples. The release kinetics of thymol from PCL, PLA, and 50/50 PCL/PLA hybrid nanofibrous mats were studied by the Peppas equation and the zero‐order, first‐order, Higuchi, and Hixon–Crowell models. Antibacterial evaluations showed that the electrospun 50/50 PCL/PLA hybrid nanofibrous samples containing thymol had satisfactory effects on Staphylococcus aureus compared with Escherichia coli bacteria during the treatment periods. In vivo rat wound‐healing and histological performance observations of thymol‐loaded 50/50 PCL/PLA nanofibrous mats, the commercial wound dressing Comfeel Plus, and gauze bandages (control) after 14‐day post‐treatment periods were evaluated. The results reveal that the electrospun 50/50 PCL/PLA hybrid nanofibers containing thymol had a remarkable wound‐closure percentage of about 92.5% after a period of 14 days. Finally, the crystallinity and thermal behavior of the electrospun 50/50 PCL/PLA hybrid nanofibrous mats with and without thymol were studied by differential scanning calorimetry. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

For the first time, it has been tried to achieve optimum conditions for electrospun poly(ε-caprolactone)/polystyrene (PCL/PS) nanofibrous samples as active wound dressings containing chamomile via D-optimal design approach. In this work, systematic in vitro and in vivo studies were carried out by drug release rate, antibacterial and antifungal evaluations, cell culture, and rat wound model along with histology observation. The optimized samples were prepared under the following electrospinning conditions: PCL/PS ratio (65/35), PCL concentration 9%(w/v), PS concentration 14%(w/v), distance between the syringe needle tip and the collector 15.5 cm, applied voltage 18 kV, and solution flow rate 0.46 mL h(-1) . The FE-SEM micrographs showed electrospun PCL/PS (65/35) nanofibrous sample containing 15% chamomile had a minimum average diameter (∼175 nm) compared to the neat samples (∼268 nm). The drug released resulted in a gradual and high amount of chamomile from the optimized PCL/PS nanofibrous sample (∼70%) in respect to PCL and PS nanofibers after 48 h. This claim was also confirmed by antibacterial and antifungal evaluations in which an inhibitory zone with a diameter of about 7.6 mm was formed. The rat wound model results also indicated that the samples loaded with 15% chamomile extract were remarkably capable to heal the wounds up to 99 ± 0.5% after 14 days post-treatment periods. The adhesion of mesenchymal stem cells and their viability on the optimized samples were confirmed by MTT analysis. Also, the electrospun nanofibrous mats based on PCL/PS (65/35) showed a high efficiency in the wound closure and healing process compared to the reference sample, PCL/PS nanofibers without chamomile. Finally, the histology analysis revealed that the formation of epithelial tissues, the lack of necrosis and collagen fibers accumulation in the dermis tissues for the above optimized samples.

ABSTRACT:In this article, we present the drug-release rate, water uptake, water permeability, morphology, and mechanical properties of a series of active wound dressing nanofibrous mats prepared via an electrospinning process of poly(lactic acid) (PLA), poly(e-caprolactone) (PCL), and their (50/50) blends loaded with different doses of tetracycline hydrochloride antibiotic. The performance of these active wound dressings in terms of a sustained and suitable drug-release rate, adequate water uptake and water permeability, and antibacterial activities were compared with those of a commercial wound dressing (Comfeel Plus). The results show that the dressings made from PCL and PLA/PCL blends showed better performance compared with the commercial wound dressing sample as far as these properties were concerned. The improved performance could be explained on the basis of the nanofibrous structure of the mats and the hydrophilicity of PCL and PLA.