ThermosenseLab, Skin Sensing Research Group, School of Health Science, University of Southampton, UK; Sport and Exercise Sciences Research Unit, SPPEFF Department, University of Palermo, Italy.
School for Engineering of Matter, Transport and Energy, Arizona State University, 501 E Tyler Mall, Tempe, AZ, 85287, USA; Julie Ann Wrigley Global Futures Laboratory, Arizona State University, Tempe, AZ, 85287, USA.
J Mech Behav Biomed Mater. 2023 Oct;146:106072. doi: 10.1016/j.jmbbm.2023.106072. Epub 2023 Aug 12.
Preliminary human studies show that reduced skin temperature minimises the risk of mechanically induced skin damage. However, the mechanisms by which cooling enhances skin tolerance to pressure and shear remain poorly understood. We hypothesized that skin cooling below thermo-neutral conditions will decrease kinetic friction at the skin-material interface. To test our hypothesis, we measured the friction coefficient of a thermally pre-conditioned index finger pad sliding at a normal load (5N) across a plate maintained at three different temperatures (38, 24, and 16 °C) in 8 healthy young adults (29±5y). To quantify the temperature distribution of the skin tissue, we used 3D surface scanning and Optical Coherence Tomography to develop an anatomically representative thermal model of the finger. Our group-level data indicated that the sliding finger with thermally affected tissues (up to 8 mm depth) experienced significantly lower frictional forces (p<0.01) at plate temperatures of 16 °C (i.e. 32% decrease) and 24 °C (i.e. 13% decrease) than at 38 °C, respectively. This phenomenon occurred consistently across participants (i.e. N = 6/8, 75%) and without large changes in skin hydration during sliding. Our complementary experimental and theoretical results provide new insights into thermal modulation of skin friction that can be employed for developing thermal technologies to maintain skin integrity under mechanical loading and shearing.
初步人体研究表明，降低皮肤温度可最大程度地降低机械引起的皮肤损伤的风险。然而，冷却增强皮肤对压力和剪切的耐受性的机制仍知之甚少。我们假设在低于热中性条件下冷却皮肤会降低皮肤-材料界面的动摩擦力。为了验证我们的假设，我们测量了在正常负载（5N）下，经过热预处理的食指垫在三个不同温度（38、24 和 16°C）的平板上滑动时的摩擦系数，该平板由 8 名健康的年轻成年人（29±5 岁）操作。为了量化皮肤组织的温度分布，我们使用 3D 表面扫描和光学相干断层扫描来开发手指的解剖学代表性热模型。我们的组级数据表明，与 38°C 相比，在 16°C（即 32%的降低）和 24°C（即 13%的降低）的平板温度下，受热影响的组织（最多 8mm 深）的滑动手指经历了显著较低的摩擦力（p<0.01）。这一现象在参与者中一致发生（即 N=6/8，75%），并且在滑动过程中皮肤水合作用没有明显变化。我们的补充实验和理论结果提供了对皮肤摩擦热调节的新见解，可用于开发热技术来维持机械加载和剪切下的皮肤完整性。
