Arimoto H, Yanai M, Egawa M
National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan.
Shiseido Research Center, Yokohama, Japan.
Skin Res Technol. 2016 Nov;22(4):505-512. doi: 10.1111/srt.12292. Epub 2016 Jun 23.
BACKGROUND/PURPOSE: Near-infrared (NIR) light with high water absorption enables us to visualize the water content distribution appeared in the superficial skin layer. The light penetration depth with the wavelength of 1920 nm is almost 100 μm from the skin surface. Thus, the water distribution in the stratum corneum can be effectively imaged by detecting the wavelength band around 1920 nm. The aim of this article was to measure the time-lapse behavior of the tiny droplet of the moisturizer spreading on the skin surface by imaging in 1920 nm wavelength band for investigating the correlation with the traditional index of the skin condition such as the water content and transepidermal water loss (TEWL).
Experiment is performed with three moisturizer products and seven volunteer subjects. The NIR image is acquired by an originally designed imaging scope equipped with the white light of the strong brightness [super continuum (SC) light], the bandpass filter with the center wavelength of 1920 nm, and the NIR image sensor. A tiny droplet of the moisturizer is put on the surface of the skin and the time-lapse images are saved. Each acquired image is analyzed from a view point of the droplet area and elapsed time for absorption into the skin. The water content and TEWL of all subjects are measured by the conventional electrical method for investigating the relationship with the measured droplet dynamics parameters.
Elapsed time for moisturizer droplet to be absorbed into the skin, the droplet area just before absorption for three moisturizer products, skin water contents, and TEWL for seven subjects were measured and correlation coefficients for each parameters were calculated. It was found that the skin with higher water contents or lower TEWL absorbed the moisturizer faster and spreads moisturizer wider. Also absorption and spreading speed depend on moisturizer property (moisturizing or fresh) which is originated from the moisturizer constituents.
The correlation values between the moisturizer dynamics on the skin surface and the traditional index of the skin property were clarified. It was found that the skin with the high water content or low TEWL absorbs the moisturizer droplet fast. The spreading area depends not only on the skin property but on the constituents of the moisturizers.
背景/目的：具有高吸水性的近红外（NIR）光使我们能够可视化浅表皮肤层中出现的水分含量分布。波长为1920 nm的光穿透深度距皮肤表面约100μm。因此，通过检测1920 nm左右的波段，可以有效地成像角质层中的水分分布。本文的目的是通过在1920 nm波段成像来测量保湿剂微小液滴在皮肤表面扩散的时间推移行为，以研究其与皮肤状况的传统指标（如水含量和经表皮水分流失（TEWL））之间的相关性。
对三种保湿产品和七名志愿者进行实验。通过配备强亮度白光[超连续谱（SC）光]、中心波长为1920 nm的带通滤波器和近红外图像传感器的原始设计成像仪获取近红外图像。将一滴微小的保湿剂滴在皮肤表面，并保存时间推移图像。从液滴面积和吸收到皮肤中的经过时间的角度分析每个获取的图像。通过传统电学方法测量所有受试者的水含量和TEWL，以研究与测量的液滴动力学参数之间的关系。
测量了保湿剂液滴被皮肤吸收的经过时间、三种保湿产品吸收前的液滴面积、七名受试者的皮肤水含量和TEWL，并计算了每个参数的相关系数。发现水含量较高或TEWL较低的皮肤吸收保湿剂更快，保湿剂扩散得更宽。吸收和扩散速度还取决于源自保湿剂成分的保湿剂特性（保湿或清爽）。
阐明了皮肤表面保湿剂动力学与皮肤特性传统指标之间的相关值。发现水含量高或TEWL低的皮肤快速吸收保湿剂液滴。扩散面积不仅取决于皮肤特性，还取决于保湿剂的成分。
