Synthesis of a colloid solution of silica-coated gold nanoparticles for X-ray imaging applications

Yoshio Kobayashi, Ryoko Nagasu, Kyosuke Shibuya, Tomohiko Nakagawa, Yohsuke Kubota, Kohsuke Gonda, Noriaki Ohuchi

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


This work proposes a method for fabricating silica-coated gold (Au) nanoparticles, surface modified with poly(ethylene glycol) (PEG) (Au/SiO 2/PEG), with a particle size of 54.8 nm. X-ray imaging of a mouse is performed with the colloid solution. A colloid solution of 17.9 nm Au nanoparticles was prepared by reducing Au ions (III) with sodium citrate in water at 80°C. The method used for silica-coating the Au nanoparticles was composed of surface-modification of the Au nanoparticles with (3-aminopropyl)-trimethoxysilane (APMS) and a sol-gel process. The sol-gel process was performed in the presence of the surface-modified Au nanoparticles using tetraethylorthosilicate, APMS, water, and sodium hydroxide, in which the formation of silica shells and the introduction of amino groups to the silica-coated particles took place simultaneously (Au/SiO2-NH 2). Surface modification of the Au/SiO2-NH2 particles with PEG, or PEGylation of the particle surface, was performed by adding PEG with a functional group that reacted with an amino group in the Au/SiO2-NH2 particle colloid solution. A computed tomography (CT) value of the aqueous colloid solution of Au/SiO2/PEG particles with an actual Au concentration of 0.112 M was as high as 922 ± 12 Hounsfield units, which was higher than that of a commercial X-ray contrast agent with the same iodine concentration. Injecting the aqueous colloid solution of Au/SiO2/PEG particles into a mouse increased the light contrast of tissues. A CT value of the heart rose immediately after the injection, and this rise was confirmed for up to 6 h.

Original languageEnglish
Article number2551
JournalJournal of Nanoparticle Research
Issue number8
Publication statusPublished - 2014 Aug


  • Au
  • Core-shell
  • Hydrogen storage
  • Poly(ethylene glycol)
  • Silica
  • X-ray contrast agent

ASJC Scopus subject areas

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Chemistry(all)
  • Modelling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics


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