Gold-Nanorod-Enhanced Fluorescence Correlation Spectroscopy of
Fluorophores with High Quantum Yield in Lipid Bilayers
Biswajit Pradhan, Thijs Aartsma, Gerhard Canters, Michel Orrit
Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2300 RA Leiden, Netherlands
Plasmonic fluorescence enhancement is used to study fluorescence correlation spectroscopy (FCS) at
micromolar concentrations. These studies previously suffered from sticking to the substrate and poor
quantum yield of the dyes. Here we demonstrate a passivating surface formed from a lipid bilayer
that prevents sticking and offers specific anchoring of probe molecules. We show that even with high
background and a weak fluorescence enhancement for dyes with a high quantum yield, it is possible to
perform FCS at high concentration. Enhanced FCS for good emitters at high concentration is recorded
by selecting enhanced signals through their higher radiative rate in the near field of gold nanorod. This
enhances the contrast of the correlation by two orders of magnitude. The lipid bilayer can be used to
anchor biomolecules and perform enhanced FCS, as we show for a protein labeled with a dye.
This work was supported by The Netherlands Organization for Scientific Research (NWO/OCW), as part
of the Frontiers of Nanoscience program.
Fig. : The scheme shows a nanorod surrounded by a lipid bilayer which contains mobile dyes. The
bottom plot shows the enhanced contrast of correlation (red) in presence of the nanorod whereas in
absence of a nanorod the contrast is low (blue).
[1] B. Pradhan, J. Phys. Chem. C 2016, 120, 25996-26003
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