Saha Tamoghna, Fang Jennifer, Mukherjee Sneha, Knisely Charles T, Dickey Michael D, Velev Orlin D
Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA.
Micromachines (Basel). 2021 Dec 4;12(12):1513. doi: 10.3390/mi12121513.
Lactate is an essential biomarker for determining the health of the muscles and oxidative stress levels in the human body. However, most of the currently available sweat lactate monitoring devices require external power, cannot measure lactate under low sweat rates (such as in humans at rest), and do not provide adequate information about the relationship between sweat and blood lactate levels. Here, we discuss the on-skin operation of our recently developed wearable sweat sampling patch. The patch combines osmosis (using hydrogel discs) and capillary action (using paper microfluidic channel) for long-term sweat withdrawal and management. When subjects are at rest, the hydrogel disc can withdraw fluid from the skin via osmosis and deliver it to the paper. The lactate amount in the fluid is determined using a colorimetric assay. During active sweating (e.g., exercise), the paper can harvest sweat even in the absence of the hydrogel patch. The captured fluid contains lactate, which we quantify using a colorimetric assay. The measurements show the that the total number of moles of lactate in sweat is correlated to sweat rate. Lactate concentrations in sweat and blood correlate well only during high-intensity exercise. Hence, sweat appears to be a suitable biofluid for lactate quantification. Overall, this wearable patch holds the potential of providing a comprehensive analysis of sweat lactate trends in the human body.
乳酸是用于确定人体肌肉健康状况和氧化应激水平的重要生物标志物。然而，目前大多数可用的汗液乳酸监测设备需要外部电源，无法在低出汗率（如人体处于休息状态时）下测量乳酸，并且无法提供关于汗液与血液乳酸水平之间关系的充分信息。在此，我们讨论我们最近开发的可穿戴汗液采样贴片的皮肤表面操作。该贴片结合了渗透作用（使用水凝胶盘）和毛细作用（使用纸质微流控通道）来进行长期汗液抽取和管理。当受试者处于休息状态时，水凝胶盘可通过渗透作用从皮肤抽取液体并将其输送到纸张上。使用比色法测定液体中的乳酸含量。在主动出汗（如运动）期间，即使没有水凝胶贴片，纸张也能收集汗液。所收集的液体含有乳酸，我们使用比色法对其进行定量。测量结果表明，汗液中乳酸的总摩尔数与出汗率相关。仅在高强度运动期间汗液和血液中的乳酸浓度才有良好的相关性。因此，汗液似乎是用于乳酸定量的合适生物流体。总体而言，这种可穿戴贴片具有对人体汗液乳酸趋势进行全面分析的潜力。
