SERS in salt wells.

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Spectroscopy

Background:

• Developing cost-effective and sensitive platforms for molecular detection is crucial.
• Nanoparticle aggregation and stability are key challenges in surface-enhanced Raman scattering (SERS).
• Existing SERS substrates often lack controlled nanostructure formation and analyte confinement.

Purpose of the Study:

• To present a facile fabrication method for salt microwells as nanoparticle containers.
• To demonstrate the utility of these salt microwells for highly sensitive SERS analysis.
• To explore their potential as microscale bioreactors.

Main Methods:

• Fabrication of salt microwells using a simple, inexpensive methodology.
• Atomic Force Microscopy (AFM) for characterizing nanostructures within the microwells.
• Confocal Raman microscopy for sensitive detection and SERS mapping of analytes.
• Utilizing different laser lines (532 nm, 632.81 nm, 785 nm) for Raman measurements.

Main Results:

• Salt microwells effectively contain favorable nanostructures, including nanoparticle dimers, enhancing Raman signal.
• High sensitivity and fidelity demonstrated for detecting dyes (rhodamine B at 10 pM), peptides (TAT at 1 nM), and proteins.
• Low background intensity and high signal-to-noise ratio achieved with various laser lines.
• SERS mapping revealed spatial confinement of analytes within the sub-femtoliter microwells.

Conclusions:

• Salt microwells offer a simple, cost-effective, and highly sensitive platform for SERS analysis.
• The controlled nanostructure formation and analyte confinement make them suitable for trace molecule detection.
• Their potential application as microscale bioreactors is highlighted due to spatial confinement capabilities.