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Updated: Jun 30, 2026
Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis
Published on: March 7, 2018
Surfactant-Free Method to Prevent Gold Nanoparticle Aggregation and Its Surface-Enhanced Raman Scattering
Yan Chen1,2, Zhiyang Zhang1,3, Yanzhou Wu1
1CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Research Center for Coastal Environmental Engineering and Technology, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
This study introduces a novel surfactant-free method using alkali regulation to stabilize gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) applications. This approach prevents aggregation and enhances SERS sensor performance by avoiding common surfactant drawbacks.
Area of Science:
- Nanotechnology
- Surface Chemistry
- Spectroscopy
Background:
- Surfactants are commonly used to stabilize colloidal gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS).
- However, surfactants introduce drawbacks like increased SERS background and blocked active sites, limiting their application.
- Existing stabilization methods often compromise nanoparticle properties.
Purpose of the Study:
- To develop a surfactant-free method for stabilizing citrate-reduced gold nanoparticles (cit-AuNPs).
- To investigate the stability mechanism of AuNPs under alkaline conditions.
- To demonstrate the advantages of this method for SERS applications.
Main Methods:
- Alkali regulation for nanoparticle stabilization.
- Exposure to harsh conditions: ligand modification, centrifugation, and salt addition.
- Characterization using SERS spectra, density functional theory (DFT) simulation, and zeta potential measurements.
Main Results:
- The surfactant-free method effectively prevents cit-AuNP aggregation under various harsh treatments.
- Alkaline conditions (pH 7 to 12) significantly increase negative charge density (approx. 6-fold) and alter molecular configuration, enhancing stability.
- Stabilized AuNPs maintained inherent optical and interface properties, showing no SERS background or blocked active sites.
Conclusions:
- Alkali regulation provides a robust, surfactant-free stabilization strategy for colloidal gold nanoparticles.
- This method preserves nanoparticle integrity and enhances SERS performance by eliminating surfactant-related interference.
- The developed approach broadens the applicability of gold nanoparticles in highly sensitive SERS sensing.
