Gold-silver alloy nanoshells: A new candidate for nanotherapeutics and diagnostics

Dana E. Gheorghe, Lili Cui, Christof Karmonik, Audrius Brazdeikis, Jose M. Penaloza, Joseph K. Young, Rebekah A. Drezek, Malavosklish Bikram

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


We have developed novel gold-silver alloy nanoshells as magnetic resonance imaging (MRI) dual T 1 (positive) and T 2 (negative) contrast agents as an alternative to typical gadolinium (Gd)-based contrast agents. Specifically, we have doped iron oxide nanoparticles with Gd ions and sequestered the ions within the core by coating the nanoparticles with an alloy of gold and silver. Thus, these nanoparticles are very innovative and have the potential to overcome toxicities related to renal clearance of contrast agents such as nephrogenic systemic fibrosis. The morphology of the attained nanoparticles was characterized by XRD which demonstrated the successful incorporation of Gd(III) ions into the structure of the magnetite, with no major alterations of the spinel structure, as well as the growth of the gold-silver alloy shells. This was supported by TEM, ICP-AES, and SEM/EDS data. The nanoshells showed a saturation magnetization of 38 emu/g because of the presence of Gd ions within the crystalline structure with r 1 and r 2 values of 0.0119 and 0.9229 mL mg -1 s -1, respectively (Au:Ag alloy = 1:1). T 1- and T 2-weighted images of the nanoshells showed that these agents can both increase the surrounding water proton signals in the T 1-weighted image and reduce the signal in T 2-weighted images. The as-synthesized nanoparticles exhibited strong absorption in the range of 600-800 nm, their optical properties being strongly dependent upon the thickness of the gold-silver alloy shell. Thus, these nanoshells have the potential to be utilized for tumor cell ablation because of their absorption as well as an imaging agent.

Original languageEnglish (US)
Article number554
Pages (from-to)1-12
Number of pages12
JournalNanoscale Research Letters
StatePublished - 2011

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics


Dive into the research topics of 'Gold-silver alloy nanoshells: A new candidate for nanotherapeutics and diagnostics'. Together they form a unique fingerprint.

Cite this