Papers Published
- D. S. Sebba and A. A. Lazarides, Robust Detection of Plasmon Coupling in Core-Satellite Nanoassemblies Linked by DNA,
Journal Of Physical Chemistry C, vol. 112 no. 47
(November, 2008),
pp. 18331 -- 18339 .
(last updated on 2009/08/04)Abstract:
Plasmon coupling is investigated in aqueous phase nanoassemblies composed of 13 nm gold "satellite" particles tethered by duplex DNA to a 50 nm gold "core" particle. The structures are comprised of a large core nanoparticle and small satellite particles such that formation of core-satellite assemblies can be detected through measurement of scattering spectra, even when an excess of unbound satellite particles are present. Rayleigh scattering spectra collected from bulk samples reveal enhanced scattering and/or red shifting of the plasmon resonance upon formation of assemblies, with the extent and character of the response determined by the number of base pairs in the duplex DNA tether. Distance-dependence of the coupling is investigated also through simulation using structural models based upon observed satellite coverage and prior measurements of interparticle separation in DNA-linked nanoparticle materials. Spectral differences between scattering from linked and unlinked assemblies are found to differ significantly from simulated spectral differences, a reflection of the sensitivity of dispersed core scattering spectra to small variations in core size, shape, and surface properties that are difficult to anticipate and characterize. In contrast, spectral differences between scattering from assemblies formed with short vs long tethers are found to match simulated difference spectra determined using the mean parameter model structures. The close correspondence between measured and simulated spectral differences for modulation of preassembled structures, but not differences associated with assembly, highlights the importance of designing coupled plasmon detection strategies that are robust to minor variations in particle properties that are difficult to control.