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Proceedings Paper

Colorimetric monitoring of nanometer distance changes in DNA-templated plasmon rulers (Conference Presentation)

Paper Abstract

The nanometer-scale sensitivity of plasmon coupling allows the translation of minute morphological changes in nanostructures into macroscopic optical signals. In particular, single nanostructure scattering spectroscopy provides a direct estimation of interparticle distances in gold nanoparticle (AuNP) dimers linked by a short DNA double-strand [M. P. Busson et al, Nano Lett. 11, 5060 (2011)]. We demonstrate here that this spectroscopic information can be inferred from simple widefield measurements on a calibrated color camera [L. Lermusiaux et al, ACS Nano 9, 978 (2015)]. This allows us to analyze the influence of electrostatic and steric interparticle interactions on the morphology of DNA-templated AuNP groupings. Furthermore, polarization-resolved measurements on a color CCD provide a parallel imaging of AuNP dimer orientations. We apply this spectroscopic characterization to identify dimers featuring two different conformations of the same DNA template. In practice, the biomolecular scaffold contains a hairpin-loop that opens after hybridization to a specific DNA sequence and increases the interparticle distance [L. Lermusiaux et al, ACS Nano 6, 10992 (2012)]. These results open exciting perspectives for the parallel sensing of single specific DNA strands using plasmon rulers. We discuss the limits of this approach in terms of the physicochemical stability and reactivity of these nanostructures and demonstrate the importance of engineering the AuNP surface chemistry, in particular using amphiphilic ligands [L. Lermusiaux and S. Bidault, Small (2015), in press].

Paper Details

Date Published: 27 April 2016
PDF: 1 pages
Proc. SPIE 9722, Colloidal Nanoparticles for Biomedical Applications XI, 97220L (27 April 2016); doi: 10.1117/12.2211019
Show Author Affiliations
Laurent Lermusiaux, Institut Langevin (France)
Sebastien Bidault, Institut Langevin (France)

Published in SPIE Proceedings Vol. 9722:
Colloidal Nanoparticles for Biomedical Applications XI
Wolfgang J. Parak; Marek Osinski; Xing-Jie Liang, Editor(s)

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