Stretchable skin hydrating PVB patches with controlled pores' size and shape for deliberate evening primrose oil spreading, transport and release.

With the increasing number of skin problems such as atopic dermatitis and the number of affected people, scientists are looking for alternative treatments to standard ointment or cream applications. Electrospun membranes are known for their high porosity and surface to volume area, which leads to a great loading capacity and their applications as skin patches. Polymer fibers are widely used for biomedical applications such as drug delivery systems or regenerative medicine. Importantly, fibrous meshes are used as oil reservoirs due to their excellent absorption properties. In our study, nano- and microfibers of poly (vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVB) were electrospun. The biocompatibility of PVB fibers was confirmed with the keratinocytes culture studies, including cells' proliferation and replication tests. To verify the usability and stretchability of electrospun membranes, they were tested in two forms as-spun and elongated after uniaxially stretched. We examine oil transport through the patches for as-spun fibers and compare it with the numerical simulation of oil flow in the 3D reconstruction of nano- and microfiber networks. Evening primrose oil spreading and water vapor transmission rate (WVTR) tests were performed too. Finally, for skin hydration tests, manufactured materials loaded with evening primrose oil were applied to the forearm of volunteers for 6 h, showing increased skin moisture after using patches. This study clearly demonstrates that pore size and shape, together with fiber diameter, influence oil transport in the electrospun patches allowing to understand the key driving process of electrospun PVB patches for skin hydration applications. The oil release improves skin moisture and can be designed regarding the needs, by manufacturing different fibers' sizes and arrangements. The fibrous based patches loaded with oils are easy to handle and could remain on the altered skin for a long time and deliver the oil, therefore they are an ideal material for overnight bandages for skin treatment.

Nano- and Microfiber PVB Patches as Natural Oil Carriers for Atopic Skin Treatment.

Atopic dermatitis (eczema) is a widespread disorder, with researchers constantly looking for more efficacious treatments. Natural oils are reported to be an effective therapy for dry skin, and medical textiles can be used as an alternative or supporting therapy. In this study, fibrous membranes from poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVB) with low and high molecular weights were manufactured to obtain nano- and micrometer fibers via electrospinning for the designed patches used as oil carriers for atopic skin treatment. The biocompatibility of PVB patches was analyzed using proliferation tests and scanning electron microscopy (SEM), which combined with a focused ion beam (FIB) allowed for the 3D visualization of patches. The oil spreading tests with evening primrose, black cumin seed, and borage were verified with cryo-SEM, which showed the advantage nanofibers have over microfibers as carriers for low-viscosity oils. The skin tests expressed the usability and the enhanced oil delivery performance for electrospun patches. We demonstrate that through the material nano- and microstructure, commercially available polymers such as PVB have great potential to be deployed as a biomaterial in medical applications, such as topical treatments for chronic skin conditions.