MXene-supported AgNPs in smart hydrogels: Shrink-enabled amplification for high-performance multi-channel SERS sensing.

BACKGROUND: With the advancement of technology and growing health concerns, high sensitivity, flexibility, and multi-channel detection have become crucial indicators for wearable intelligent sensors. RESULTS: Inspired by the volume contraction of hydrogels upon ethanol exposure, a strategy combining MXene with in situ reduction of silver nanoparticles has been used to construct a three-dimensional, high-sensitivity SERS substrate (MX-SNP PAH-based SERS substrate). This design not only enriches target molecules but also enables dual enhancement of charge transfer and electromagnetic enhancement by inducing inter-particle spacing between silver nanoparticles and VCT. The developed SERS substrate allows for the quantitative analysis of pesticide molecules (thiram, 1 nM), small molecules such as p-mercaptobenzoic acid (pMBA, 1 nM), and microplastics like polystyrene (PS, 6.25 μg mL). Additionally, by analyzing the sweat SERS spectra, it was possible to successfully quantify blood glucose levels (4.5 mM). SIGNIFICANCE: This innovative MX-SNP PAH-based SERS substrate design provides valuable insights for the development of flexible wearable sensors, with significant application potential in food safety, water quality analysis, and health monitoring.