Electrospun nanofibers are a unique type of nano-delivery system with improved porosity, surface area to volume ratio and tensile strength. These homogenous structures, possessing diameters in the submicron level, have inherent characteristics which aid in skin interaction, liquid absorption and permeability of oxygen and water. As a result, electrospun nanofibers can be used to fabricate sheet masks for treatment of various skin conditions especially acne vulgaris, a chronic skin disease.
Ultrafine fibers can be fabricated using polymers like polyvinyl alcohol (PVA). PVA is a water soluble, non-toxic, biocompatible and biodegradable polymer. To prepare facial sheet masks, these PVA fibers need to be crosslinked with substances like citric acid to form water insoluble nanofibers to prevent collapse on absorbing water. Esterification of the three carboxyl groups of citric acid with hydroxyl groups of PVA lead to crosslinking between the two materials.
Zinc oxide (ZnO) has been proven to be an effective antibacterial agent against a variety of micro-organisms like S. aureus, E.coli as well as Cutibacterium acnes, the gram positive bacterium responsible for acne. However, using zinc oxide directly on skin may lead to toxic effects due to adsorption of ZnO on skin. So PVA nanofibers may be used to embed ZnO nanoparticles for skin treatment. The large surface area of this delivery system provides an enhanced contact area between the nanofibers and the skin leading to improved anti-acne effect.
Experimental analysis
In the current study, researchers fabricated spherical and monodispersed ZnO nanoparticles using sol-gel technique, the morphology of which was confirmed using transmission electron microscopy. To form electrospun nanofibers, a high voltage electric field was applied to the polymeric solution taken in a syringe. A jet formed from the nozzle of the syringe dried and deposited in the collector to produce uniform nanofibers. As the percentage of ZnO incorporated into the nanofiber increased, an increase in the swelling ratio of the nanofiber sheet could be seen.
Antibacterial studies were performed as per the parallel streak standard method. At a concentration of 7% ZnO in PVA, an inhibitory effect was seen against C.acnes. The formation of reactive oxygen species (ROS) like hydroxyl radicals, superoxide and hydrogen peroxide by zinc oxide in water led to the release of zinc ions. The ROS and Zn2+ ions formed were capable of entering into bacterial cells and destructing their cellular component through electrostatic interactions.
The enhanced swelling and efficacious antibacterial effect make ZnO loaded PVA electrospun nanofibers an ideal system to be used as anti-acne sheet masks. Although in vitro testing yields suitable results, extensive in vivo testing would also be required to understand the functioning of these formulations when used by individuals.
Thus, it can be seen that nano-delivery systems can be leveraged to obtain a simple solution to a chronic issue like acne faced by millions globally.
Source: Antiacne Effects of PVA/ZnO Composite Nanofibers Crosslinked by Citric Acid for Facial Sheet Masks
Jeong S, Oh S-G, Department of Chemical Engineering, Hanyang University, Republic of Korea
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