A Simple and Sensitive\nWearable SERS Sensor Utilizing\nPlasmonic-Active Gold Nanostars

Wearable sweat sensors hold great potential for offering\ndetailed\nhealth insights by monitoring various biomarkers present in sweat,\nsuch as glucose, lactate, uric acid, and urea, in real time. However,\nmost previously reported sensors, primarily based on electrochemical\ntechnology, are limited to monitoring only a single analyte at a given\ntime. This study introduces a simple, sensitive, wearable patch based\non surface-enhanced Raman spectroscopy (SERS), integrated with highly\nplasmonically active sharp-branched gold nanostars (GNS) for the simultaneous\ndetection of three sweat biomarkers: lactate, urea, and glucose. We\nhave fabricated the GNS on commercially available adhesive tape, resulting\nin achieving a low-cost, flexible, and adhesive wearable SERS patch.\nThe limits of detection for lactate, urea, and glucose were achieved\nat 0.7, 0.6, and 0.7 μM, respectively, which are significantly\nlower than the clinically relevant concentrations of these biomarkers\nin sweat. We further evaluated the performance of our wearable SERS\npatch during outdoor activities, including sitting, walking, and running.\nTo evaluate its overall effectiveness, we simultaneously measured\nthe concentrations of lactate, urea, and glucose during these activities.\nOverall, our simple, sensitive wearable SERS sensor represents a significant\nbreakthrough by enabling the simultaneous detection of lactate, urea,\nand glucose present in sweat, marking a major step toward future applications\nin autonomous and noninvasive personalized healthcare monitoring at\nhome.