Plasmonic liquid marbles: a miniature substrate-less SERS platform for quantitative and multiplex ultratrace...

Area of Science:

• Analytical Chemistry
• Materials Science
• Nanotechnology

Background:

• Liquid marbles, inspired by aphids, are versatile for microreactors, micropumps, and sensing.
• Current liquid marble sensing is limited to qualitative colorimetry, hindering precise quantification.
• There is a need for advanced analytical platforms for sensitive and simultaneous detection of trace analytes.

Purpose of the Study:

• To fabricate a plasmonic liquid marble as a substrate-less analytical platform.
• To enable simultaneous multiplex quantification and identification of ultratrace analytes across separate phases.
• To overcome the limitations of qualitative colorimetry-based detection in current liquid marble sensing.

Main Methods:

• Fabrication of a plasmonic liquid marble.
• Coupling the plasmonic liquid marble with ultrasensitive Surface-Enhanced Raman Spectroscopy (SERS).
• Quantitative examination of ultratrace analytes at an aqueous-solid-organic interface.

Main Results:

• Demonstrated excellent mechanical stability of the plasmonic liquid marble.
• Achieved ultrasensitive detection limits as low as 0.3 fmol for analytes.
• Obtained an analytical enhancement factor of 5×10^8.
• Successfully performed simultaneous quantitative detection of methylene blue and coumarin across phases, matching individual detection results.

Conclusions:

• Plasmonic liquid marbles coupled with SERS offer a powerful substrate-less platform for quantitative analysis.
• This method enables simultaneous multiplex detection of ultratrace analytes across different phases with high sensitivity.
• The developed platform significantly advances liquid marble-based sensing capabilities beyond qualitative colorimetry.