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Proceedings Paper

Spectroscopic and transport measurements of single molecules in solution using an electrokinetic trap
Author(s): Quan Wang; W. E. Moerner
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Paper Abstract

In aqueous solution, diffusion generally limits the observation window of a nano-meter sized single molecule to milliseconds and prevents quantitative determination of spectroscopic and transport properties molecule-by-molecule. The anti-Brownian electrokinetic (ABEL) trap is a feedback-based microfluidic device that enables prolonged (multiseconds) observation of single molecules in solution. The amount of information that can be extracted from each molecule in solution is thus boosted by three orders of magnitude. We describe recent advances in extending the ABEL trap to conduct both spectroscopic and transport measurements of single trapped molecules. First, by combining the trap with multi-parameter fluorescence detection, synchronized dynamics in different observables can be visualized in solution. We use single molecules of Atto 633 as an example and show that this popular label switches between different emissive states under common imaging conditions. Next, we show how transport properties of trapped single molecules can be extracted in addition to spectroscopic readouts. Due to their direct sensitivity to molecular size and charge, measured transport coefficients can be used to distinguish different molecular species and trace biomolecular interactions in solution. We demonstrate this new paradigm by monitoring DNA hybridization/melting in real-time.

Paper Details

Date Published: 4 March 2014
PDF: 10 pages
Proc. SPIE 8950, Single Molecule Spectroscopy and Superresolution Imaging VII, 895004 (4 March 2014); doi: 10.1117/12.2038320
Show Author Affiliations
Quan Wang, Stanford Univ. (United States)
W. E. Moerner, Stanford Univ. (United States)


Published in SPIE Proceedings Vol. 8950:
Single Molecule Spectroscopy and Superresolution Imaging VII
Jörg Enderlein; Ingo Gregor; Zygmunt Karol Gryczynski; Rainer Erdmann; Felix Koberling, Editor(s)

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