Eccrine sweat is a rich and largely unexplored biofluid that contains a range of important biomarkers, from electrolytes, metabolites, micronutrients and hormones to exogenous agents, each of which can change in concentration with diet, stress level, hydration status and physiologic or metabolic state. Traditionally, clinicians and researchers have used absorbent pads and benchtop analyzers to collect and analyze the biochemical constituents of sweat in controlled, laboratory settings. Recently reported wearable microfluidic and electrochemical sensing devices represent significant advances in this context, with capabilities for rapid, in situ evaluations, in many cases with improved repeatability and accuracy. A limitation is that assays performed in these platforms offer limited control of reaction kinetics and mixing of different reagents and samples. Here, we present a multi-layered microfluidic device platform with designs that eliminate these constraints, to enable integrated enzymatic assays with demonstrations of in situ analysis of the concentrations of ammonia and ethanol in microliter volumes of sweat. Careful characterization of the reaction kinetics and their optimization using statistical techniques yield robust analysis protocols. Human subject studies with sweat initiated by warm-water bathing highlight the operational features of these systems.

中文翻译：

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柔软的，具有皮肤界面的微流体系统，带有集成的酶促测定法，用于测量汗液中氨和乙醇的浓度。

内分泌汗液是一种丰富的，尚未开发的生物流体，其中包含一系列重要的生物标志物，从电解质，代谢物，微量营养素和激素到外源性物质，每种物质的浓度都会随着饮食，压力水平，水合状态以及生理或代谢状态而变化。传统上，临床医生和研究人员使用吸水垫和台式分析仪在受控的实验室环境中收集和分析汗液的生化成分。最近报道的可穿戴微流体和电化学传感设备在此方面代表了重大进展，具有快速，原位的能力评估，在许多情况下可提高重复性和准确性。局限性在于，在这些平台上进行的测定只能有限地控制反应动力学以及不同试剂和样品的混合。在这里，我们提出了一种多层微流控设备平台，该平台的设计消除了这些限制，从而实现了集成酶促测定，并具有对微升体积汗液中氨和乙醇浓度进行原位分析的演示。仔细表征反应动力学并使用统计技术对其进行优化，可得到可靠的分析方案。通过温水洗澡引发的汗液对人体进行的研究突出了这些系统的操作功能。