Monitoring biomarkers of mental stress, such as cortisol, in sweat is essential for understanding the body's endocrine response to stressful stimuli and assessing cognitive status. Nevertheless, the current stress monitoring method primarily depends on measuring heart rate variability, which lacks specificity and dramatically limits its applicability. This study introduces a wearable surface-enhanced Raman scattering (SERS) biosensor for the non-invasive monitoring of cortisol in sweat. Additionally, the biosensor functions as a pH calibration tool. In brief, a silk fibroin-based binary nanosphere array structure was synthesized to serve as the SERS substrate, demonstrating favorable sensitivity, reproducibility, and mechanical stability. Moreover, we have developed a pseudoknot-assisted aptamer probe for the specific recognition and detection of cortisol. The probe was commercially synthesized to effectively restrict Raman signaling molecules to different states before and after cortisol binding, thereby mitigating background noise and improving signal conversion efficiency. Furthermore, microfluidic channels have been utilized to collect sweat without additional perspiration assistance. By integrating epidermal microfluidics into the wearable SERS patch, dynamic monitoring of cortisol levels and pH in sweat was achieved. Through the substitution of specific aptamers on the sensing component, the system can monitor alternative biomarkers present in sweat, presenting encouraging possibilities and promising prospects in personalized medicine and health monitoring.

中文翻译：

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基于丝素蛋白的可穿戴微流控 SERS 贴片，用于无创监测汗液皮质醇和 pH 值


监测汗液中精神压力的生物标志物（如皮质醇）对于了解身体对压力刺激的内分泌反应和评估认知状态至关重要。然而，目前的压力监测方法主要依赖于测量心率变异性，这缺乏特异性并极大地限制了其适用性。本研究介绍了一种可穿戴表面增强拉曼散射 （SERS） 生物传感器，用于无创监测汗液中的皮质醇。此外，生物传感器还可用作 pH 校准工具。简而言之，合成了一种基于丝素蛋白的二元纳米球阵列结构作为 SERS 底物，表现出良好的灵敏度、可重复性和机械稳定性。此外，我们还开发了一种假结辅助适配体探针，用于特异性识别和检测皮质醇。该探针是市面上合成的，可有效限制拉曼信号分子在皮质醇结合前后处于不同状态，从而减轻背景噪声，提高信号转换效率。此外，微流体通道已被用于收集汗液，而无需额外的排汗帮助。通过将表皮微流控技术集成到可穿戴 SERS 贴片中，实现了对汗液中皮质醇水平和 pH 值的动态监测。通过在传感组件上替换特定的适配子，该系统可以监测汗液中存在的替代生物标志物，为个性化医疗和健康监测提供令人鼓舞的可能性和广阔的前景。