Quantitative SERS using the sequestration of small molecules inside precise plasmonic nanoconstructs.

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Supramolecular Chemistry

Background:

• Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique for detecting molecules.
• Precise control over nanoparticle spacing is crucial for reproducible SERS signals.
• Trapping small molecules within nanostructures can enhance detection sensitivity.

Purpose of the Study:

• To investigate the use of cucurbit[8]uril (CB[8]) as a molecular linker for gold nanoparticles.
• To develop a quantitative SERS method for small molecule detection using CB[8].
• To explore the potential of CB[8]-mediated nanoparticle junctions for analytical applications.

Main Methods:

• Formation of gold nanoparticle (AuNP) junctions using cucurbit[8]uril (CB[8]) as a precise subnanometer linker.
• Utilizing the cavity of CB[8] to simultaneously trap target small molecules.
• Employing surface-enhanced Raman spectroscopy (SERS) to detect and quantify the trapped molecules.

Main Results:

• CB[8] successfully created reproducible subnanometer junctions between gold nanoparticles.
• The CB[8] cavity effectively trapped various small molecules at the nanoparticle junctions.
• SERS detection of trapped molecules was achieved with high reproducibility.
• Absolute quantification of small molecules was demonstrated down to 10(-11) M levels based on explicit SERS frequency shifts.

Conclusions:

• Cucurbit[8]uril serves as an effective molecular component for creating precise nanoparticle junctions.
• This CB[8]-mediated approach enables highly sensitive and quantitative SERS detection of small molecules.
• The developed method represents a new analytical paradigm for quantitative SERS analysis.