Partitioning and assembly of metal particles and their bioconjugates in aqueous two-phase systems

Marcus R. Helfrich, Mahnaz El-Kouedi, Mark R. Etherton, Christine Dolan Keating

Research output: Contribution to journalArticlepeer-review

83 Scopus citations


The behavior of metal nanospheres and nanowires and their bioconjugates in aqueous two-phase systems (ATPS) is described. The ATPS used in this work comprised poly(ethylene glycol) (PEG), dextran, and water or aqueous buffer. Au and Ag nanospheres less than 100 nm in diameter partition between the PEG-rich and dextran-rich phases on the basis of their surface chemistry and can be separated on this basis. Larger Au nanospheres and wires accumulate at the interface between the two aqueous phases. The influence of polymer molecular weight and concentration on interfacial assembly of Au wires is described. DNA-derivatized nanowires at the aqueous/aqueous interface retain the ability to selectively bind to fluorescent complementary DNA. In addition, Au nanoparticles have been bound to Au wires via selective DNA hybridization at the ATPS interface. Transmission electron microscopy and thermal denaturation experiments confirm that DNA-driven assembly is responsible for the formation of the nanosphere/wire assemblies. These results demonstrate the biocompatibility of the two-phase interface and point to future use as scaffolding in biorecognition-driven assembly.

Original languageEnglish (US)
Pages (from-to)8478-8486
Number of pages9
Issue number18
StatePublished - Aug 30 2005

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry


Dive into the research topics of 'Partitioning and assembly of metal particles and their bioconjugates in aqueous two-phase systems'. Together they form a unique fingerprint.

Cite this