Skin-Conformal Sandwich-Structured SERS Superlattice Platform for Non-Invasive Depression Detection

M) with excellent reproducibility (RSD = 9.02%) and high chemical specificity. To adapt the sensing unit for on-body use, the SERS chip is embedded within an adhesive, deformable, and biocompatible polyethylene glycol hydrogel. Featuring engineered microfluidic channels, this hydrogel autonomously transports sweat to the sensing area, thereby guaranteeing precise detection alongside consistent conformal contact and comfort. This multifunctional, integrated platform has the potential to overcome longstanding limitations in sensitivity, stability, biocompatibility, and sweat management that hinder conventional wearable sensors. It provides a powerful route toward a versatile design framework for next-generation wearable bioelectronics.