In this paper, we present a disposable, colorimetric, user-friendly and mass-customizable dermal patch for chronological collection and discrete real-time in situ measurement of sweat secretion over a small area of skin. The patch consists of a laminated filter paper patterned into radially arranged channels/fingers with water-activated dyes at their tips. As channels are filled during perspiration, their tips change color once fully saturated, providing easily identifiable levels of water loss which in turn can be mapped to personal dehydration levels. The patch can be manufactured at low cost in a variety of sizes to allow hydration monitoring for individuals participating in activities under different conditions (intensity, temperature, humidity, etc.). Furthermore, we describe an analytical model that enables mass customization of such a flexible wearable system accommodating a broad range of sweat rates and volumes to generate patch designs that are personalized to an individual’s sweat rate, desired time of usage, and the temporal resolution of the required feedback. As a proof-of-concept demonstration, we characterized laser-fabricated patches that cover (7 cm × 5 cm) area of skin having various wicking materials, thicknesses (180–540 µm), and pore sizes (3–11 µm). Tests were conducted at various flow rates simulating different sweating intensities in the range of 1.5–15 mg/cm²/min. Experimental results for the case of a half-marathon runner targeting 90 min of usage and sweating at a rate of 1.5 mg/cm²/min indicated measurement accuracy of 98.3% when the patch is completely filled.

在本文中，我们提出了一种一次性、比色、用户友好且可大规模定制的皮肤贴片，用于按时间顺序收集和离散实时原位测量小面积皮肤上的汗液分泌。该贴片由层压滤纸组成，该滤纸图案化为径向排列的通道/手指，其尖端带有水活性染料。由于通道在出汗过程中被填满，一旦完全饱和，它们的尖端就会改变颜色，提供易于识别的失水水平，进而可以映射到个人脱水水平。该贴片可以低成本制造成各种尺寸，以便对在不同条件（强度、温度、湿度等）下参与活动的个人进行水合作用监测。此外，我们描述了一个分析模型，该模型能够对这种灵活的可穿戴系统进行大规模定制，以适应各种出汗率和汗量，以生成针对个人出汗率、所需使用时间和所需反馈的时间分辨率进行个性化的贴片设计. 作为概念验证演示，我们表征了覆盖（7 cm × 5 cm）皮肤区域的激光制造贴片，具有各种芯吸材料、厚度（180–540 µm）和孔径（3–11 µm）。在不同的流速下进行测试，模拟 1.5–15 mg/cm 范围内的不同出汗强度 作为概念验证演示，我们表征了覆盖（7 cm × 5 cm）皮肤区域的激光制造贴片，具有各种芯吸材料、厚度（180–540 µm）和孔径（3–11 µm）。在不同的流速下进行测试，模拟 1.5–15 mg/cm 范围内的不同出汗强度 作为概念验证演示，我们表征了覆盖（7 cm × 5 cm）皮肤区域的激光制造贴片，具有各种芯吸材料、厚度（180–540 µm）和孔径（3–11 µm）。在不同的流速下进行测试，模拟 1.5–15 mg/cm 范围内的不同出汗强度² /分钟。半程马拉松运动员以使用 90 分钟和以 1.5 mg/cm ² /min的速度出汗的情况下的实验结果表明，当贴片完全填充时，测量准确度为 98.3%。