Enhanced emission of fluorophores on shrink-induced wrinkled composite structures.
We introduce a manufacturable and scalable method for creating tunable wrinkled ferromagnetic-metallic structures to enhance fluorescence signals. Thin layers of nickel (Ni) and gold (Au) were deposited onto a pre-stressed thermoplastic (shrink wrap film) polymer. Heating briefly forced the metal films to buckle when the thermoplastic retracted, resulting in multi-scale composite 'wrinkles'. This is the first demonstration of leveraging the plasmons in such hybrid nanostructures by metal enhanced fluorescence (MEF) in the near-infrared wavelengths. We observed more than three orders of magnitude enhancement in the fluorescence signal of a single molecule of goat anti-mouse immunoglobulin G (IgG) antibody conjugated to fluorescein isothiocyanate, FITC, (FITC-IgG) by two-photon excitation with these structures. These large enhancements in the fluorescence signal at the nanoscale gaps between the composite wrinkles corresponded to shortened lifetimes due to localized surface plasmons. To characterize these structures, we combined fluctuation correlation spectroscopy (FCS), fluorescence lifetime imaging microscopy (FLIM), and two-photon microscopy to spatially and temporally map the hot spots with high resolution.
Deparment of Chemical Engineering & Materials Science, University of California, Irvine, California 92697, USA.
Himanshu
H
Sharma
Department of Developmental and Cell Biology, Laboratory for Fluorescence Dynamics, University of California, Irvine, California 92697, USA ; Department of Biomedical Engineering, Laboratory for Fluorescence Dynamics, University of California, Irvine, California 92697, USA.
Michelle A
MA
Digman
Department of Biomedical Engineering, University of California, Irvine, California 92697, USA.
Natasha
N
Felsinger
Department of Biomedical Engineering, Laboratory for Fluorescence Dynamics, University of California, Irvine, California 92697, USA.
Enrico
E
Gratton
Deparment of Chemical Engineering & Materials Science, University of California, Irvine, California 92697, USA ; Department of Biomedical Engineering, University of California, Irvine, California 92697, USA.
Michelle
M
Khine