An eco-friendly zein nanoparticle as robust cosmetic ingredient ameliorates skin photoaging

Zein colloidal particles, which have generally regarded as safe (GRAS) status, have been routinely used in formulations of oral nutraceuticals but not in skin care products. Herein, we constructed for the first time zein-based topical vehicles to address skin photoaging. To this end, we fabricated a new type of eco-friendly nanoparticles by co-assembling zein with hyaluronic acid (HA), a cell-specific molecule, to encapsulate hydrophobic tetrahydrocurcumin (THC) with an aim to improve its cutaneous bioavailability. Impressively, the prepared nanoparticles could increase the solubility of THC in water by 72.84 times, and were stable at pH 4–10. In particular, the topical delivery systems were effective in UVB-induced cell and animal photoaging models, and were able to restore the accumulation of matrix metalloproteinase-1 (MMP-1) and inflammatory factors to the normal levels at the selected conditions. In addition, the biotransformation of THC in HaCaT cells was observed and clarified. This strategy may open up new promising avenues for developing innovative nanocosmetics containing anti-photoaging ingredient.