Lossless enrichment of trace analytes in levitating droplets for multiphase and multiplex detection

Concentrating a trace amount of molecules from liquids, solid objects, or the gas phase and delivering them to a localized area are crucial for almost any trace analyte detection device. Analytes within a liquid droplet resting on micro/nanostructured surfaces with liquid-repellent coatings can be concentrated during solvent evaporation. However, these coatings suffer from complex manufacturing procedures, poor versatility, and limited analyte enrichment efficiency. Here, we report on the use of an acoustic levitation platform to losslessly concentrate the analyte molecules dissolved in any volatile liquid, attached to solid objects, or spread in air. Gold nanoparticles can be simultaneously concentrated with the analytes in different phases, realizing sensitive, surface-enhanced Raman scattering detection even at attomolar (10(-18) mol/L) concentration levels. The acoustic levitation platform-enabled, lossless analyte enrichment can significantly increase the analytical performance of many conventional microsensing techniques. Efficient enrichment of molecules from liquids, solid objects, or the gas phase is critical for their detection at trace concentrations. Here, the authors report on the lossless enrichment of analytes in droplets using acoustic levitation for multiphase and multiplex SERS detection.

Automated summary

This study reports on the use of an acoustic levitation platform for lossless concentration of trace molecules, enabling analyte detection in liquids, solid objects, and the gas phase. The platform allows for the concentration of analytes dissolved in volatile liquids and the simultaneous concentration of gold nanoparticles, enabling sensitive surface-enhanced Raman scattering detection even at extremely low concentrations.