Regensburg 2007 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 14: Biological Systems
CPP 14.4: Vortrag
Dienstag, 27. März 2007, 11:00–11:15, H47
Single molecule fluorescence at microstructured nanopatterns — •Alex G F de Beer1, Marco Schwieder1, 2, Eva Bock1, 2, Guenter Majer1, and Joachim P Spatz1, 2 — 1Max-Planck Institute for Metals Research, Dept. of New Materials and Biosystems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany — 2University of Heidelberg, Dept. of Biophysical Chemistry, Im Neuenheimer Feld 253, D-69120 Heidelberg, Germany
Nanopatterns created using self assembly of block copolymer micelles can be used as a negative resist for electron beam lithography. This allows the preparation of surfaces consisting of patches of gold nanodots [1].
We use TIRF single molecule microscopy to study thiol-modified Alexa 488 labelled streptavidin molecules attached to single gold dots. The stoichiometry of attachment is of interest, along with electrodynamic interactions between the dye molecules and the gold dots. The size of the streptavidin molecule (roughly 6 nm) is small enough so that it fully lies within the interaction range of a gold particle (about 16 nm) [2]. We show a clear influence of the nanopattern on the properties of the dye, with an increased photobleaching resistance and decreased dye intensity. Using this decreased fluorescence intensity and accompanying increased photostability, it is possible to generate a photobleaching contrast between bound and unbound molecules, thus allowing to selectively image bound molecules only.
[1] R. Glass et al., Advanced Functional Materials 13, 569-575 (2003)
[2] E. Dulkeith et al., Nano Lett. 5(4), 585-589 (2005)