X-ray photoelectron spectroscopy and transmission electron microscopy analysis of silver-coated gold nanorods designed for bionanotechnology applications

Fumiya Watanabe, Zeid A. Nima, Takumi Honda, Masatoshi Mitsuhara, Minoru Nishida, Alexandru S. Biris

研究成果: Contribution to journalArticle査読

8 被引用数 (Scopus)

抄録

Multicomponent nano-agents were designed and built via a core-shell approach to enhance their surface enhanced Raman scattering (SERS) signals. These nano-agents had 36 nm ×12 nm gold nanorod cores coated by 4 nm thick silver shell films and a subsequent thin bifunctional thiolated polyethylene glycol (HS-PEG-COOH) layer. Ambient time-lapsed SERS signal measurements of these functionalized nanorods taken over a two-week period indicated no signal degradation, suggesting that large portions of the silver shells remained in pure metallic form. The morphology of the nanorods was characterized by transmission electron microscopy (TEM) and ultra-high resolution scanning TEM. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) were utilized to assess the oxidation states of the silver shells covered by HS-PEG-COOH. The binding energies of Ag 3d XPS spectra yielded very small chemical shifts with oxidation; however, the AES peak shapes gave meaningful information about the extent of oxidation undergone by the nano-agent. While the silver shells without HS-PEG-COOH coatings oxidized significantly, the silver shells with HS-PEG-COOH remained predominantly metallic. In fact, six month-old samples still retained mostly metallic silver shells. These findings further demonstrate the stability and longevity of the nanostructures, indicating their significant potential as plasmonically active agents for highly sensitive detection in various biological systems, including cancer cells, tissues, or even organisms.

本文言語英語
論文番号025704
ジャーナルNanotechnology
28
2
DOI
出版ステータス出版済み - 1 13 2017

All Science Journal Classification (ASJC) codes

  • バイオエンジニアリング
  • 化学 (全般)
  • 材料科学(全般)
  • 材料力学
  • 機械工学
  • 電子工学および電気工学

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