Structurally Stable Attractive Nanoscale Emulsions with Dipole-Dipole Interaction-Driven Interdrop Percolation.

This study introduces an extremely stable attractive nanoscale emulsion fluid, in which the amphiphilic block copolymer, poly(ethylene oxide)-block-poly(ϵ-caprolactone) (PEO-b-PCL), is tightly packed with lecithin, thereby forming a mechanically robust thin-film at the oil-water interface. The molecular association of PEO-b-PCL with lecithin is critical for formation of a tighter and denser molecular assembly at the interface, which is systematically confirmed by T2 relaxation and DSC analyses. Moreover, suspension rheology studies also reflect the interdroplet attractions over a wide volume fraction range of the dispersed oil phase; this results in a percolated network of stable drops that exhibit no signs of coalescence or phase separation. This unique rheological behavior is attributed to the dipolar interaction between the phosphorylcholine groups of lecithin and the methoxy end groups of PEO-b-PCL. Finally, the nanoemulsion system significantly enhances transdermal delivery efficiency due to its favorable attraction to the skin, as well as high diffusivity of the nanoscale emulsion drops.

Effects of Kyunghee Facial Resistance Program (KFRP) on mechanical and elastic properties of skin.

INTRODUCTION: Facial skin aging is influenced by weakened mimetic muscles. Resistance training of facial mimetic muscles could be one of practical strategy to defend against age-related changes. The aim of this study was to investigate the effects of an exercise program (KFRP: Kyunghee Facial Resistance Program) designed for facial mimetic muscles on the mechanical properties and elasticity of facial skin. METHODS: For this study, 16 healthy female volunteers aged 35-58 participated in KFRP for eight weeks. The mechanical and elastic properties of skin were measured using a Cutometer® on the face and neck. RESULTS: The parameters representing skin fatigue decreased and the parameters representing skin elasticity increased significantly compared to the baseline in all measured regions. The ability of re-deformation of skin increased significantly except the zygomaticus and platysma muscle regions. All measured regions of skin became firmer and the ability to return to the initial position was also significantly improved compared to the baseline. Visco-elasticiy of the skin was not significantly altered. CONCLUSIONS: The skin became more firm and elastic through KFRP. This method of resistive exercise had a significantly positive influence on the mechanical properties and elasticity of facial and neck skin.