Structural characterization of PEGylated polyethylenimine-entrapped gold nanoparticles: An NMR study

Benqing Zhou, Mingwu Shen, I. Bányai, Xiangyang Shi

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

NMR spectroscopy has been proven to be a useful method to characterize the spatial structure of polymer-protected nanoparticles (NPs). In the present study, polyethylenimine (PEI) partially modified with polyethylene glycol (PEG) was used as a template to form gold NPs (Au NPs) via either sodium borohydride reduction or PEI amine-mediated self-reduction of Au salt. The formed two types of PEGylated PEI-entrapped Au NPs (PEI-mPEG-Au NPs) were characterized by UV-vis spectroscopy and transmission electron microscopy, and their internal structures were characterized using NMR techniques. We show that the formed PEI-mPEG-Au NPs display a significant downfield shift in the proton signals of the innermost PEI methylene rather than the outer PEG methylene when compared to that of PEI-mPEG without Au NP entrapment. This result indicates that a strong interaction exists between the Au NPs and the innermost PEI, suggesting that the Au NPs are entrapped within individual PEI-mPEG instead of being stabilized by the surface PEG chains. In addition, the NMR diffusion coefficients of PEI (or PEG) in the PEI-mPEG-Au NPs are much higher than that of PEI-mPEG (without Au NPs), further demonstrating the effective Au NP entrapment. The present study provides a new physical insight into the internal spatial structure of polymer-protected Au NPs disclosed by NMR techniques, which may be used for structural characterization of other NP/polymer nanocomposites.

Original languageEnglish
Pages (from-to)5390-5397
Number of pages8
JournalThe Analyst
Volume141
Issue number18
DOIs
Publication statusPublished - Sep 21 2016

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Polyethyleneimine
Gold
Nanoparticles
nuclear magnetic resonance
gold
Nuclear magnetic resonance
Polyethylene glycols
Polymers
polymer
nanoparticle
spectroscopy
Nanocomposites
Ultraviolet spectroscopy
Transmission Electron Microscopy
Nuclear magnetic resonance spectroscopy

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry

Cite this

Structural characterization of PEGylated polyethylenimine-entrapped gold nanoparticles : An NMR study. / Zhou, Benqing; Shen, Mingwu; Bányai, I.; Shi, Xiangyang.

In: The Analyst, Vol. 141, No. 18, 21.09.2016, p. 5390-5397.

Research output: Contribution to journalArticle

Zhou, Benqing ; Shen, Mingwu ; Bányai, I. ; Shi, Xiangyang. / Structural characterization of PEGylated polyethylenimine-entrapped gold nanoparticles : An NMR study. In: The Analyst. 2016 ; Vol. 141, No. 18. pp. 5390-5397.
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