A Wearable PVA Film Supported TiO2 Nanoparticles Decorated NaNbO3 Nanoflakes-Based SERS Sensor for Simultaneous Detection of Metabolites and Biomolecules in Human Sweat Samples

Sweat is one of the non-invasive diagnostic biofluids that provides critical information about human health. In this work, a wearable sweat sensor integrated with a polymer-based fluid absorption layer modified with titanium oxide (TiO2) nanoparticles decorated sodium niobate (NaNbO3) nanoflakes in porous polyvinyl alcohol (PVA) film matrix is demonstrated for the detection of vital metabolites (such as glucose and urea) and biomolecules (ascorbic acid (AA) and uric acid (UA)) in human sweat samples via surface-enhanced Raman scattering (SERS). The TiO2@NaNbO3/PVA (SERS patch) exhibits a low limit of detection (LOD) of 0.50, 0.80, 1.00, and 100 mm towards AA, glucose, UA, and urea, respectively. The SERS patch displays a high enhancement factor with a low accumulation time of 20s which can be ascribed to the surface coordination between the TiO2@NaNbO3 and the analytes leading to interfacial charge-transfer transition (ICTT). Besides, the photo-induced charge transfer (PICT) resonance significantly amplifies the SERS signal. The SERS patch is successful in the simultaneous determination of AA, glucose, UA, and urea in simulated sweat samples with minimal mutual interference. The high efficacy of the SERS patch proves it as an ideal platform for a wide range of wearable healthcare monitoring applications.

Automated summary

This study demonstrates a wearable sweat sensor integrated with a polymer-based fluid absorption layer and modified with nanoparticles for the detection of metabolites and biomolecules in human sweat samples. The sensor shows a low detection limit and a fast response time, and successfully detects multiple substances in simulated sweat samples.