  The last two decades have witnessed a dramatic growth of wearable sensor
technology, mainly represented by flexible, stretchable, on-skin electronic
sensors that provide rich information of the wearer's health conditions and
surroundings. A recent breakthrough in the field is the development of wearable
chemical sensors based on surface-enhanced Raman spectroscopy (SERS) that can
detect molecular fingerprints universally, sensitively, and noninvasively.
However, while their sensing properties are excellent, these sensors are not
scalable for widespread use beyond small-scale human health monitoring due to
their cumbersome fabrication process and limited multifunctional sensing
capabilities. Here we demonstrate a highly scalable, wearable SERS sensor based
on an easy-to-fabricate, low-cost, ultrathin, flexible, stretchable, adhesive,
and bio-integratable gold nanomesh. It can be fabricated in any shape and worn
on virtually any surface for label-free, large-scale, in-situ sensing of
diverse analytes from low to high concentrations (10 nM - 1 mM). To show the
practical utility of the wearable SERS sensor, we test the sensor for the
detection of sweat biomarkers, drugs of abuse, and microplastics. This wearable
SERS sensor represents a significant step toward the generalizability and
practicality of wearable sensing technology.
