Cholesterol Nanofiber Patches with Sustainable Oil Delivery Eliminate Inflammation in Atopic Skin

Abstract

Atopic skin is dry and itchy and lacks integrity. Impaired skin barrier results from altered lipid composition of the skin. A crucial skin lipid, cholesterol, provides flexibility and homeostasis of the cell membranes' lipid bilayer. Cholesterol-based creams and natural oils, especially blackcurrant seed oil, are beneficial for skin care as they hydrate the skin and improve its integrity. The major atopic symptom, skin dryness, can be overcome by the application of porous patches enhanced with cholesterol and natural oil. The base of the patches is constructed of polyimide (PI) nanofibers with cholesterol coatings and externally added blackcurrant seed oil. The presence of cholesterol in PI mats hinders the passage of oil through the patches to the skin, resulting in sustained and prolonged skin hydration. The theoretical and numerical investigations of oil dynamics in porous mats confirmed the experimental results, showing a prolonged skin hydration effect up to 6 h. Additionally, as demonstrated by in vivo tests on atopic mice, cholesterol patches lower serum immunoglobulin E levels and expression of proinflammatory cytokines in the skin, thereby accelerating skin healing. Our results hold great promise for the long-term application of the patches in atopic dermatitis treatment.

Keywords: atopic; cholesterol; oil delivery; oil transport; patches; skin.

Figure 1

SEM micrographs of (a) PI mat, (b) PI mat with cholesterol, (c) FTIR spectra of the PI mat, PI mat with cholesterol, electrosprayed cholesterol, and raw cholesterol, (d) TGA results of these mats and raw cholesterol, and (e) MTS results indicating proliferation of keratinocytes on PI mat, PI mat with cholesterol, and control substrate—TCPS. *Statistically significant differences (p < 0.05) from the nonparametric Kruskal–Wallis test.

Figure 2

Schematics of (a) oil passing through the mat, (b) oil capillary rise along the mat, and (c) oil spreading on the mat. Position of the air–oil interface in numerical simulation of oil and oil with cholesterol mixture (d) passing through PI mat, (e) transported in the plane of the mat, (f) diffusivity of oil or oil with cholesterol mixture in direction through the mats, (g) dynamics of oil capillary rise along the mats, (h) estimated velocity of oil spreading on the mats, and (i) diffusivity of oil or oil with cholesterol mixture in the porous mats in directions along and on the mats.

Figure 3

(a) Scheme of experimental arrangement of patches and oils on volunteers’ forearms. Differences in the skin hydration level in 14 volunteers, before and after application of (b) empty mats, (c) PI mats with pure oil and pure oil, (d) PI mats with cholesterol with pure oil, and oil with cholesterol mixture, (e) amount of cholesterol release from PI mats with cholesterol to blackcurrant seed oil, (f) scheme of in vivo experiment on atopic mouse, and (g) expression of IL-1β and (h) TNF-α in OVA-sensitized mouse skin of 10 mice after treatment with patches. X-axes legend: (1) control, (2) after sensitization with OVA, (3) after sensitization with OVA and treatment with pure PI mats, (4) after sensitization with OVA and treatment with PI mats with oil, and (5) after sensitization with OVA and treatment with PI mats with cholesterol with oil. *Statistically significant differences (p < 0.05) from the nonparametric Kruskal–Wallis test. Pictures of mouse skin sections after (i) sensitization with OVA, (j) sensitization with OVA, and treatment with PI mats with cholesterol with oil.