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CP: Chemische Physik

CP 18: Sondersymposium: Einzelmolekülspektroskopie

CP 18.2: Talk

Thursday, March 12, 1998, 11:50–12:10, H18

On the Track to Two Dimensional Single Molecule Detection of Biomolecules in Solution — •Harald Mathis, Geert Kalusche, and John McCaskill — Institut f"ur Molekulare Biotechnologie e.V., Beutenbergstra"se 11, D-07745 Jena

Spatial cross-correlation of photons is better suited to the characterization of the trajectories of biomolecules than single channel fluorescence correlation spectroscopy. The limiting case of full spatial imaging with the necessary temporal resolution to allow single photon cross-correlation would be the method of choice. Developments in x-y-strip detectors from particle physics and MHz gatable multi-channel-plate image intensifiers when combined with parallel configurable hardware offer the possibility to extend single or few channel single molecule detection to two dimensions, even for molecules in free solution.
In this contribution first results with the new detector will be presented and the principal benefits and limitation of this approach compared with APD arrays discussed. Potential applications include molecular sorting size characterization (in free solution and in gel) and observation of stochastic chemical kinetics. The results of the zero-dimensional single molecule detection with an open confocal setup will be presented. We will show, that DNA and RNA oligonucleotides < 100 bp are detectable in microstructures when labelled merely by reversible binding intercalators such as Thiazol Orange and its derivatives.