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Fabrication of polydimethylsiloxane (PDMS)-Based Flexible Surface-Enhanced Raman Scattering (SERS) Substrate for Ultrasensitive Detection
Published on: November 17, 2023
Silver nanoparticles self assembly as SERS substrates with near single molecule detection limit
Meikun Fan1, Alexandre G Brolo
1Department of Chemistry, University of Victoria, Victoria, Canada.
Physical Chemistry Chemical Physics : PCCP
|August 20, 2009
Summary
Highly sensitive surface-enhanced Raman scattering (SERS) substrates were created using self-assembled silver nanoparticles. These substrates achieve zeptomole detection limits for molecules like Nile blue A, enabling ultra-trace analysis.
Area of Science:
- Nanotechnology
- Materials Science
- Spectroscopy
Background:
- Surface-enhanced Raman scattering (SERS) requires highly sensitive substrates for detecting trace analytes.
- Fabricating uniform and reproducible SERS substrates with numerous 'hot-spots' remains a challenge.
Purpose of the Study:
- To develop a bottom-up strategy for fabricating highly sensitive SERS substrates.
- To optimize the deposition of silver nanoparticles (Ag NPs) for enhanced SERS performance.
- To characterize the morphology and SERS capabilities of the fabricated substrates.
Main Methods:
- Fabrication of SERS substrates via self-assembly of Ag NPs onto glass slides using a 3-mercaptopropyltrimethoxysilane (MPTMS) sol-gel linker.
- Characterization using UV-Vis spectroscopy and Atomic Force Microscopy (AFM) after sequential Ag NP depositions.
- Evaluation of SERS performance using Nile blue A and oxazine 720 as probe molecules with 632.8 nm and 785 nm laser excitations.
Main Results:
- Homogeneous distribution of Ag NP aggregates achieved with increased deposition.
- Optimal SERS performance observed after six Ag NP depositions.
- Zeptomole-level detection limits demonstrated, with high reproducibility (RSD% ~19%) and giant Raman signal enhancement.
Conclusions:
- The bottom-up self-assembly strategy effectively produces highly sensitive and reproducible SERS substrates.
- Optimized Ag NP deposition leads to enhanced SERS signals, enabling detection of extremely low molecule concentrations.
- These substrates show significant potential for ultra-trace analysis applications.
