Stability and electrostatic assembly of Au nanorods for use in biological assays

Manish Sethi, GaEun Joung, Marc Knecht

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

The structure, stability, and aggregation potential of short Au nanorods under biological-based solution conditions have been studied. These attributes were studied using UV-vis spectroscopy, transmission electron microscopy, ζ-potential analysis, and dynamic light scattering. The stability and aggregation potential of the materials depended strongly upon both the purity and the solvent used to prepare Au nanorod solutions. When the Au nanorods were dissolved in Tris buffer at concentrations less than 10.0 mM, no aggregation was observed; however, when the solvent was comprised of Tris buffer with concentrations between 10.0 and 100 mM, significant aggregation of the materials occurred. This effect resulted in a dramatic broadening and shift in the absorbance maxima of the longitudinal surface plasmon resonance. At Tris buffer concentrations of greater than 100 mM, minimal to no aggregation of the materials in solution was observed. Such an ability is based upon electrostatic aggregation of the materials in solution mediated by the anions associated with the buffer system; at concentrations between 10.0 and 100 mM, the anions present electrostatically bind to the surfaces of the Au nanorods that are positively charged, resulting in cross-linking of the materials. At higher buffer concentrations, a sufficient number of anions are present in solution to template around the entire surface of each individual nanorod, in effect neutralizing the charge and producing an electronic double layer, which prevents aggregation. Such studies are timely as they represent an analysis of the stability and range of use of Au nanorods for biological-based applications where remarkable potential exists.

Original languageEnglish
Pages (from-to)317-325
Number of pages9
JournalLangmuir
Volume25
Issue number1
DOIs
StatePublished - Jan 6 2009
Externally publishedYes

Fingerprint

Nanorods
nanorods
Electrostatics
Assays
Agglomeration
assembly
electrostatics
buffers
Tromethamine
Anions
anions
Negative ions
Buffers
surface plasmon resonance
Surface plasmon resonance
Dynamic light scattering
Ultraviolet spectroscopy
purity
light scattering
templates

ASJC Scopus subject areas

  • Electrochemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Science(all)
  • Spectroscopy

Cite this

Stability and electrostatic assembly of Au nanorods for use in biological assays. / Sethi, Manish; Joung, GaEun; Knecht, Marc.

In: Langmuir, Vol. 25, No. 1, 06.01.2009, p. 317-325.

Research output: Contribution to journalArticle

Sethi, Manish ; Joung, GaEun ; Knecht, Marc. / Stability and electrostatic assembly of Au nanorods for use in biological assays. In: Langmuir. 2009 ; Vol. 25, No. 1. pp. 317-325.
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