Nanowire-based squalene oleogel repairs skin photoaging.

Long-term exposure to ultraviolet B (UVB) radiation induces the accumulation of free radicals in the skin, resulting in oxidative damage and accelerated aging. As a natural anti-oxidant, squalene has been applied as a cosmetic additive. Nonetheless, the liquid oil state of squalene and its low solubility in water usually limits the practical application of squalene. Recently, phosphotungstate calcium nanowires has been synthesized to gelatinize oily solvents, making it feasible to fabricate stable oleogel formulation containing squalene. Herein, the squalene/phosphotungstate calcium nanowires (Sql/PWC) oleogel has been specifically designed and applied to treat skin photoaging. Such oleogel was comprised of oil-based structures that closely mimic the skin's natural lipids, resulting in enhanced skin penetration, better retention of active ingredients within the skin, and superior stability as compared to traditional hydrogel, especially under UVB exposure. It was found that the application of Sql/PWC oleogel on UVB-irradiated skin successfully decreased epidermal thickness, increased dermal thickness, and promoted the expression of elastin, collagen and skin barrier marker. Meanwhile, RNA-Sequencing results further revealed that the Sql/PWC oleogel alleviated UVB photo-damage through its antioxidant and anti-inflammatory activities in the skin, which were key factors in the aging process. We believe this study will not only bring new perspectives for skin photoaging treatment but also promotes the broader application of oleogel in the cosmetics industry.