Fluorescence techniques have been enriched by the ability to observe single molecules opening a new realm of applications ranging from superresolution microscopy to DNA sequencing and single-molecule FRET. The small signals arising from single molecules restrict the application of these techniques, however, to very bright and photostable dyes. Single-molecule detection is also limited to low concentrations due to the size of diffraction-limited observation volumes. Just recently, nanophotonic approaches have emerged to decrease the observation volumes and to increase the fluorescence signal by fluorescence enhancement.
In this project, we envision the development of self-assembled nanophotonic structures that enhance fluorescent signals in an ultra-small volume. We will use DNA origami nanostructures as scaffolds to build nanoantennas from noble metal nanoparticles. The nanoantennas increase the electric field locally in the gap between them thus forming fluorescence hot-spots. Molecules of interest will be placed in these hot-spots by handles that are additionally offered by the DNA origami. An organic fluorescent dye placed in the hot-spot will, for example, act as a reporter of the enhancement.
We will design DNA origami structures and decorate them with metallic nanoparticles and nanorods. We will optimize the material for broadband fluorescence enhancement. We will reduce the interparticle distance and vary the particle size as well as we will control the alignment of the nanostructures with respect to the laser excitation polarization. The nanoantenna devices will be studied by time-resolved single-molecule fluorescence spectroscopy and single-particle scattering spectroscopy. In combination with dyes of low intrinsic quantum yield we expect extraordinary high fluorescence enhancement of more than three orders of magnitude that might lead to new labels, assay formats and (bio-)photonic applications.
Contact:
Dr. Guillermo Acuna
TU Braunschweig
Institute of Physical and Theoretical Chemistry
AG Tinnefeld for NanoBioSciences
Phone: +49 531 391 7377
Hans-Sommer-Str. 10
38106 Braunschweig, Germany
g.acuna(at)tu-bs.de
Prof. Dr. Philip Tinnefeld
TU Braunschweig
Institut für Physikalische & Theoretische Chemie - NanoBioSciences
and Braunschweig Integrated Center of Systems Biology (BRICS)
and Laboratory for Emerging Nanometrology (LENA)
Hans-Sommer-Straße 10
38106 Braunschweig
p.tinnefeld(at)tu-braunschweig.de
www.tu-braunschweig.de/pci/research/tinnefeld