Oct. 25, 2022

New Surface-enhanced Raman scattering (SERS) analysis method enables ultra-sensitive analysis - Liquid interface-assisted SERS (LI-SERS) -

RIKEN No.: 09143

Inventors

Koji Sugioka- Advanced Laser Processing Research Team, Shi Bai- Advanced Laser Processing Research Team

Background

SERS is a widely used method for analyzing trace amounts of substances with high sensitivity. It can detect substances at nanomolar (nM/10^-9 molar) concentration levels. Although new methods for detecting extremely small femtomolar (fM/10^-15 molar) concentrations of substances have been proposed, they have several drawbacks, such as complicated equipment/measurement methods and only transient achievement of high detection sensitivity.

Summary

In LI-SERS, SERS analysis is performed at an air-liquid interface formed on the SERS substrate. Using this method, detection of ultra-low trace substances below 10 aM (10^-17M) can be achieved. In addition to this, highly-sensitive analysis will be possible on large biomolecules such as DNA and β-amyloid, the defining biomarker of Alzheimer’s Disease.

Image of the schematic diagram of the implementation for LI-SERS

Figure 1: Schematic diagram of the implementation for LI-SERS

Figure of mechanism of ultra-sensitive analysis using LI-SERS

Figure 2: Mechanism of ultra-sensitive analysis using LI-SERS

Figure of attomolar level sensing by LI-SERS (sample is Rhodamine 6G)

Figure 3: Attomolar level sensing by LI-SERS (sample is Rhodamine 6G)

Merits

Substance-detection sensitivity with the new analysis method (attomolar level, aM, or 10^-18M) is so good it cannot be compared with traditional methods.
No special equipment is required for detection, and use of traditional Raman spectroscopy is possible (enables simplified analysis).
Because the highly sensitive SERS analysis is implemented on the substrate itself, even better detection sensitivity can be achieved in the future.

Applications

Detection of ultra-low trace substances (application for academics; environmental analysis such as detection of contamination; inspection for food safety; etc.)
Early diagnoses of diseases such as Alzheimer's Disease
Prompt and highly-sensitive analysis for viruses and bacteria

References

1. Application Number: PCT/JP2021/021620
2. S. Bai, D. Serien, Y. Ma, K. Obata, and K. Sugioka, “Attomolar Sensing Based on Liquid-Interface Assisted Surface Enhanced Raman Scattering in Microfluidic Chip by Femtosecond Laser Processing”, ACS Appl. Mater. Interfaces, 12, 42328–4233 (2020).
3. S. Bai, X. Ren, K. Obata, Y. Ito, and K. Sugioka, “Label-free trace detection of bio-molecules by liquid-interface assisted surface-enhanced Raman scattering using a microfluidic chip”, Opto-Electron. Adv. (in press)