Hybrid Gold-DNA Origami Nanostructures for the Enhancement and Sensing of Single Molecules
C. Corti1, E. Y. Gayet1, G. Vazquez2, N. Triomphe2, N. Aissaoui2,3, S. Marguet4, G. Bellot2, S. Bidault1
1Institut Langevin, ESPCI Paris, Université PSL, CNRS, Paris, France
2CBS - Centre de Biochimie Structurale, CNRS, INSERM, Montpellier, France
3CiTCoM, Université Paris Cité, CNRS, France
4CEA Saclay, Univ. Paris-Saclay, IRAMIS, NIMBE, Gif-sur-Yvette, France
Plasmonic resonators featuring high extinction cross sections, as well as strongly confined and enhanced optical fields, have found diverse applications by optimizing light-matter interactions but also by providing an optical contrast to chemical analytes in biosensing. Structural DNA nanotechnology provides numerous degrees of freedom to develop hybrid plasmonic resonators with a perfectly controlled chemical environment in order to optimize these optical properties. In this presentation, I will discuss two approaches that we have recently developed using DNA origamis to maximize the interaction between quantum emitters and plasmonic resonators, as well as to detect single DNA single strands on a color camera thanks to plasmon coupling.
I will detail how a hybrid nanostructure based on spherical gold particles and a dynamic DNA origami can detect single biochemical interactions by monitoring nanoscale conformation changes using near-field plasmon coupling. Single nanostructure scattering spectroscopy measurements can be correlated to a simple colorimetric detection scheme on a CCD camera. These measurements indicate that digital colorimetric biosensing is achievable on low-cost equipment.
DNA origamis can also organize anisotropic particles with an excellent control over their relative orientations. I will describe how a DNA origami can be used to assemble two gold nanocubes in such a way that a single fluorescent molecule is squeezed between their tips. This allows a strong enhancement of the local density of optical states, accelerating spontaneous emission rates by several orders of magnitude. These systems open exciting perspectives to recover coherent light-matter interactions at room temperature by overcoming ultrafast phonon-induced dephasing.
Schematic representations and TEM images of hybrid gold-DNA origami nanostructures: dimer of 40 nm gold nanospheres for the colorimetric sensing of single DNA strands (left) and dimer of 40 nm gold nanocubes to enhance the fluorescence of single emitters (right).