High-specificity SERS sensing with magnet-powered hierarchically structured micromotors.

This work reports a hierarchically structured micromotor (HSM) surface-enhanced Raman scattering (SERS) platform comprising 3D tubular configurations with nanostructured outer walls. The HSMs can be powered by an external magnetic field in solution to enrich molecules with promoted adsorption efficiency. The nanostructured outer wall serves as containers to collect molecules and produce strong localized surface plasmon resonance to intensify Raman of the enriched molecules. Further coupling of HSMs after molecular enrichment can produce additional plasmonic hotspots at the sites where the molecules were enriched, providing a solution to manipulate molecules to enter the plasmonic hotspot region. Moreover, functionalizing specific molecules on the outer wall of HSMs enables high-specificity SERS sensing for benzaldehyde (BA) and Cu ions in liquid. This SERS platform demonstrates great potential for practical applications in biochemical analysis and environmental monitoring, offering a rapid and sensitive tool for detecting low-concentration analytes in liquid.