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BP: Fachverband Biologische Physik

BP 16: Poster Session I

BP 16.1: Poster

Dienstag, 27. März 2007, 17:00–19:30, Poster D

Preparation of dense arrays of end-tethered DNA on solid substrates — •hui li, juha koota, ina seuffert, alexander andré, georg maret, and thomas gisler — Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany

We discuss various routes to produce dense end-tethered arrays of long-chain DNA molecules to solid substrates, using DNA carrying end groups such as biotin or thiol which specifically bind to surface-anchored streptavidin or gold.

Conventional end-tethering by adsorption of coiled DNA results in low tethering densities and mushroom-like conformations [1] due to the entropic repulsion of the coils. Using DC electric fields applied via conducting substrates such as gold or streptavidin-coated indium-tin oxide, DNA can be driven to the surface by electrophoresis. However, the high viscosity of the high DNA concentration near the surface dramatically slows down the tethering, resulting in only moderate enhancements of the tethering density.

As an alternative approach we exploit the liquid crystalline order in DNA solutions induced by osmotic stress [2] or by convective deposition onto a pinned contact line occurring in a "coffee ring" [3]. We investigate the effects of end-functionalization and end-tethering on liquid crystalline textures, and resulting tethering densities.

[1] R. Lehner, et al. Phys. Rev. Lett. 96 (2006), 107801.

[2] R. Podgornik, et al. Proc. Natl. Acad. Sci. USA 93 (1996), 4261-4266.

[3] I.I. Smalyukh, et al. Phys. Rev. Lett. 96 (2006), 177801.