Nanofibrils from the self-assembly of the naturally occurring saponin glycyrrhizic acid (GA) can be used to produce an oil-in-water emulsion foam with a long-term stability. Through homogenization and aeration followed by rapid cooling, stable emulsion foams can be produced from the mixtures of sunflower oil and saponin nanofibrils. At high temperatures, the GA fibrils form a multilayer assembly at the interface, creating an interfacial fibrillar network to stabilize the oil droplets and air bubbles generated during homogenization. A subsequent rapid cooling can trigger the self-assembly of free GA fibrils in the continuous phase, forming a fibrillar hydrogel and thus trapping the oil droplets and air bubbles. The viscoelastic bulk hydrogel showed a high yield stress and storage modulus, which lead to a complete arrest of the liquid drainage and a strong slowdown of the bubble coarsening in emulsion foams. The jamming of the emulsion droplets in the liquid channels as well as around the bubbles was also found to be able to enhance the foam stability. We show that such stable foam systems can be destroyed rapidly and on demand by heating because of the melting of the bulk hydrogel. The reversible gel-sol phase transition of the GA hydrogel leads to thermoresponsive emulsion foams, for which the foam stability can be switched from stable to unstable states by simply raising the temperature. The emulsion foams can be further developed to be photoresponsive by incorporating internal heat sources such as carbon black particles, which can absorb UV irradiation and convert the absorbed light energy into heat. This new class of smart responsive emulsion foams stabilized by the natural, sustainable saponin nanofibrils has potential applications in the food, pharmaceutical, and personal care industries.
This study aimed to investigate the protective effects of bovine elastin hydrolysates on UV-induced skin photoaging in mice and to identify the potent antiphotoaging peptides. Results showed that the ingestion of elastin peptides could obviously ameliorate epidermis hyperplasia and fibroblast apoptosis, and increase the content of hydroxyproline and water in photoaging skin in vivo (p < 0.05). Furthermore, four peptides with elastase inhibitory activity were purified and identified, including GLPY, PY, GLGPGVG, and GPGGVGAL. Interestingly, GLPY and GPGGVGAL exhibited the highest inhibition activity with 58.77% and 42.91% at 10 mΜ, respectively. This might be attributed to the N-terminal Gly, C-terminal Leu, and Pro at the third position of the N-terminus, which showed stronger affinity and interaction with elastase. Moreover, GLPY and GPGGVGAL could also inhibit the apoptosis of fibroblasts effectively at 50 μΜ (p < 0.01). It suggested that elastin peptides had great potential to prevent and regulate skin photoaging.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.