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Updated: Aug 28, 2025
Optical Trapping of Plasmonic Nanoparticles for In Situ Surface-Enhanced Raman Spectroscopy Characterizations
Published on: June 23, 2022
Size-controlled synthesis of cyclodextrin-capped gold nanoparticles for molecular recognition using surface-enhanced
Koichiro Saito1, Keegan McGehee1, Yasuo Norikane1,2
1Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST) Higashi 1-1-1, Tsukuba Ibaraki 305-8565 Japan koichiro.saito@aist.go.jp.
Abstract:
Cyclodextrin (CD)-capped gold nanoparticles (AuNPs) can be applied in sensing, catalysis, and self-assembly processes due to their molecular recognition ability. As the plasmon resonance of AuNPs depends on their size, the size-controlled synthesis of CD-capped AuNPs is essential for the development of these applications. Herein, we successfully synthesized β-CD-capped AuNPs with diameters of 24-85 nm using a seed-mediated growth method. The AuNPs were prepared using a β-CD as both the reducing agent and the capping agent. Harsh reagents such as NaBH4 and NaOH were not used. The size-controlled synthesis of β-CD-capped AuNPs was achieved by changing the amount of seed solution. We fabricated monolayers of β-CD-capped AuNPs by liquid-liquid interfacial self-assembly for application in surface-enhanced Raman scattering (SERS). The SERS intensity is significantly improved by using larger β-CD-capped AuNPs. In addition, we found that β-CDs can detect pyrene with higher sensitivity than α-CDs on the basis of the difference in molecular recognition ability between α-CDs and β-CDs.
