Introduction to Electrospinning in Cosmetics

Fig 1. Mangosteen hull extracts have been incorporated into electrospun fibers [Courtesy of T Chu. This work is licensed under a Creative Commons Attribution 2.0 Generic]

Electrospinning has the potential for use various cosmetic applications such as facial masks, perfumes, deodorants, anti-perspirants just to name a few. A common feature of these applications is that they may be used in the form of membrane which can be easily fabricated by electrospinning. The ease of incorporating active ingredients into electrospun fibers also makes this process feasible for cosmetic applications. Emulsion electrospinning has been used to fabricate membranes containing volatile fragrance. Poly(vinyl alcohol) (PVA) fibrous matrix has been demonstrated to release encapsulated (R)-(+)-limonene over 15 days under ambient conditions [Camerlo et al 2013].

Delivery of active ingredients via electrospun membrane to the skin is one of the most direct applications. Extracts from the fruit hull of mangosteen up to 10% w/w (of polyvinyl alcohol weight) has been blended with polyvinyl alcohol (PVA) in distilled water and electrospun [Opanasopit et al 2008]. The release profile of the electrospun membrane showed an initial burst release within the first 20 min compared to a more gradual release by PVA film. This is probably due to the high surface area and greater swelling of the PVA electrospun membrane. Depending on the desired release profile, a burst release may be preferable if it is the intention of the product to use in short treatment duration. Fathi-Azarbayjani et al (2010) investigated the skin penetration of active ingredients in an electrospun anti-wrinkle nanofiber face mask. Using polyvinyl alcohol as the carrier, gold nanoparticles, randomly methylated β-cyclodextrin, ascorbic acid, retinoic acid, or collagen was added to the mixture and electrospun. Skin permeation study was carried out in vitro using adult human abdominal skin. Permeation of retinoic acid and ascorbic acid were shown to be better for the nanofiber mask compared to cotton sheet pre-moistened with vitamin solutions. An advantage of the nanofiber mask is that it can be supplied dry and wet prior to use so that the degradation of the active ingredients are minimized in contrast with commercially available facemask that is often supplied pre-wetted. Another commonly used compound for skin protection is vitamin E. Sheng et al (2013) used a blend of water soluble vitamin E and silk fibroin for electrospinning to produce nanofibrous membrane with up to 8 wt% of vitamin E. In vitro tests by culturing of fibroblast showed that the membrane with vitamin E was able to protect the cells against oxidation stress induced by tert-butyl hydroperoxide. Only when the concentration of tert-butyl hydroperoxide (tBHP) reaches 400 µM then there is a significant drop in the cell viability. This contrasts with the results of cells cultured on coverslip which showed a significant drop when just 50 µM of tBHP was added. The membrane showed an initial burst released of 7% of the encapsulated vitamin E within 30 min followed by gradual release over 72 h.

Many conventional cosmetic ingredients are available in dry powder or particle form. An alternative method to blending active ingredients into a polymer solution and electrospinning is to use dry powder impregnation technology. Teno et al (2020) used this process to load electrospun pullulan membrane with chitin nanofibrils-nanolignin-glycyrrethinic acid (CLA) complexes. Pullulan is a bio-based polymer which is hydrophilic and has great potential use as a polymer in cosmetics application Pullulan was electrospun to form a membrane before CLA particles were coated on one side. An alternating electric field was then applied from the other side such that the particles were dispersed across the porosities of the membrane. The size of the CLA particles was less than 10 µm with most of the particles with a diameter of 3 µm. The electrospun pullulan fiber has an average diameter of 1.13 µm. The CLA particles were homogeneously distributed and adhering to the surface of the pullulan fibers. Human trials were carried out on topical application of pullulan/CLA composite membrane. The membrane was found to yield significant reduction of forehead and crow's feet wrinkles with significant increase of moisturizing levels after two weeks and four weeks of topical application.

(a) Pullulan electrospun mesh being inserted into the pilot equipment for dry impregnation. (b) Sketch of the dry impregnation technology (S-Preg). (c) Pullulan electrospun mesh impregnated with CLA complexes [Teno et al 2020].

Representative SEM micrograph (2500×) of electrospun pullulan mesh impregnated with CLA, visible as microparticles attached to the fibers. Scale bar is 40 microns [Teno et al 2020].