Department of Nanoengineering, Center of Wearable Sensors, University of California San Diego, 9500 Gilman Dr., San Diego, CA, 92093, USA.
College of Chemistry and Materials Science, Shanghai Normal University, Shanghai, 200234, China.
Adv Mater. 2021 May;33(18):e2008465. doi: 10.1002/adma.202008465. Epub 2021 Mar 30.
Tracking fluctuations of the cortisol level is important in understanding the body's endocrine response to stress stimuli. Traditional cortisol sensing relies on centralized laboratory settings, while wearable cortisol sensors are limited to slow and complex assays. Here, a touch-based non-invasive molecularly imprinted polymer (MIP) electrochemical sensor for rapid, simple, and reliable stress-free detection of sweat cortisol is described. The sensor readily measures fingertip sweat cortisol via highly selective binding to the cortisol-imprinted electropolymerized polypyrrole coating. The MIP network is embedded with Prussian blue redox probes that offer direct electrical signaling of the binding event to realize sensitive label-free amperometric detection. Using a highly permeable sweat-wicking porous hydrogel, instantaneously secreted fingertip sweat can be conveniently and rapidly collected without any assistance. By eliminating time lags, such rapid (3.5 min) fingertip assay enables the capture of sharp variations in cortisol levels, compared to previous methods. Such advantages are demonstrated by tracking cortisol response in short cold-pressor tests and throughout day-long circadian rhythm, along with gold-standard immunoassay validation. A stretchable epidermal MIP sensor is also described for directly tracking cortisol in exercise-induced sweat. The rapid touch-based cortisol sensor offers an attractive, accessible, stressless avenue for quantitative stress management.
跟踪皮质醇水平的波动对于理解身体对应激刺激的内分泌反应非常重要。传统的皮质醇感应依赖于集中的实验室设置，而可穿戴的皮质醇传感器则限于缓慢而复杂的分析。在这里，描述了一种基于触摸的无创分子印迹聚合物（MIP）电化学传感器，用于快速、简单和可靠地无应激检测汗液中的皮质醇。该传感器通过与皮质醇印迹的电聚合聚吡咯涂层的高度选择性结合，容易地测量指尖汗液中的皮质醇。MIP 网络中嵌入了普鲁士蓝氧化还原探针，为结合事件提供直接的电信号，实现了敏感的无标记安培检测。使用高度可渗透的吸湿多孔水凝胶，可以方便、快速地收集即时分泌的指尖汗液，无需任何帮助。通过消除时间滞后，与以前的方法相比，这种快速（3.5 分钟）指尖检测能够捕捉到皮质醇水平的急剧变化。通过跟踪短时间冷压测试和全天昼夜节律中的皮质醇反应，并与金标准免疫测定验证，证明了这些优势。还描述了一种用于直接跟踪运动引起的汗液中皮质醇的弹性表皮 MIP 传感器。这种基于触摸的快速皮质醇传感器为定量应激管理提供了一种有吸引力、可及性强、无应激的途径。
