Plasma treated-double layer electrospun fiber mats from thermoplastic polyurethane and gelatin for wound healing applications

Conventional wound treatment options provide a barrier against exogenous microbial penetration but cannot simultaneously provide an antibacterial characteristic and promote healing. However, bioactive dressings can accelerate wound healing and have an antibacterial effect in addition to being able to cover and protect lesions. In this study, double-layer thermoplastic polyurethane (TPU)-gelatin fibrous dressings that mimic the epidermis and dermis layers of the skin were fabricated via electrospinning technique. As a bioactive agent, Hypericum perforatum oil (HPO) was utilized to impart antibacterial and therapeutic properties to the dressings. Tannic acid was also used in fiber mat formulations as a cross-linking agent. Oxygen plasma treatment was applied as a surface activation technique to improve adhesion of TPU and gelation layers. The fiber structure of the mats was revealed by a scanning electron microscopy (SEM) study. Fourier transform infrared (FTIR) spectroscopy was used to demonstrate HPO loading onto the mats. The water vapor transmission rate (WVTR) and fluid absorbency of the mats were compared with some commercial dressings. According to these results, it can be suggested that the mats can be used for moderate to high exudative wounds. All dressings, even the control sample showed antibacterial features against both Staphylococcus aureus and Escherichia coli bacteria due to the tannic acid. In vitro wound healing assays were carried out on the plasma-treated sample and it was observed that the sample did not negatively affect the migration and proliferation abilities of the cells which are necessary for wound healing. Overall results indicated that the plasma-treated fibrous mat would be a good candidate as a wound dressing material having an antibacterial character.