Sweat loss monitoring is important for understanding the body’s thermoregulation and hydration status, as well as for comprehensive sweat analysis. Despite recent advances, developing a low-cost, scalable, and universal method for the fabrication of colorimetric microfluidics designed for sweat loss monitoring remains challenging. In this study, we propose a novel laser-engraved surface roughening strategy for various flexible substrates. This process permits the construction of microchannels that show distinct structural reflectance changes before and after sweat filling. By leveraging these unique optical properties, we have developed a fully laser-engraved microfluidic device for the quantification of naked-eye sweat loss. This sweat loss sensor is capable of a volume resolution of 0.5 μL and a total volume capacity of 11 μL, and can be customized to meet different performance requirements. Moreover, we report the development of a crosstalk-free dual-mode sweat microfluidic system that integrates an Ag/AgCl chloride sensor and a matching wireless measurement flexible printed circuit board. This integrated system enables the real-time monitoring of colorimetric sweat loss signals and potential ion concentration signals without crosstalk. Finally, we demonstrate the potential practical use of this microfluidic sweat loss sensor and its integrated system for sports medicine via on-body studies.

Graphic abstract

中文翻译：

---

无串扰双模式汗液传感系统，通过结构反射率的变化进行肉眼汗液损失定量

出汗量监测对于了解身体的体温调节和水合状态以及全面的出汗分析非常重要。尽管最近取得了进展，但开发一种低成本、可扩展且通用的方法来制造用于汗液流失监测的比色微流体仍然具有挑战性。在这项研究中，我们提出了一种针对各种柔性基材的新型激光雕刻表面粗糙化策略。该过程允许构建在汗液填充之前和之后显示出明显的结构反射率变化的微通道。通过利用这些独特的光学特性，我们开发了一种完全激光雕刻的微流体装置，用于量化肉眼汗液流失。该汗液流失传感器的体积分辨率为0.5μL，总体积容量为11μL，并且可以定制以满足不同的性能要求。此外，我们报告了一种无串扰双模式汗液微流体系统的开发，该系统集成了 Ag/AgCl 氯化物传感器和匹配的无线测量柔性印刷电路板。该集成系统能够实时监测比色汗液损失信号和潜在离子浓度信号，而不会产生串扰。最后，我们通过身体研究展示了这种微流控汗液流失传感器及其集成系统在运动医学中的潜在实际用途。

 图文摘要