Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 12: Soft-Matter Nanofluidic Devices

AKB 12.1: Invited Talk

Tuesday, March 28, 2006, 14:00–14:30, ZEU 255

Transport and Reaction-Diffusion Phenomena in Soft-Matter Nanofluidic Devices — •Owe Orwar — Department of Chemistry and Biotechnology, Chalmers University of Technology, SE-412 96 G*teborg, Sweden

Methods for the construction of fluid state lipid bilayer networks consisting of nanotube-conjugated vesicles are presented. Unilamellar vesicles ( 5-25 µm in diameter) can be connected with nanotubes (30-300 nm in diameter) in a controlled fashion using both self-organization, and forced shape transformations, allowing design of nanofluidic networks of particular geometries and topologies[1-4]. The membrane composition (e.g. lipids, transporters, receptors, and catalytic sites) and container contents (e.g. catalytic particles, organelles, and reactants) can be controlled on the single-container level allowing complex chemical programming of networks [5].

Transport in nanotubes and materials exchange between conjugated containers can be obtained by using three different methods. 1. Marangoni flows where transport is modulated by changes in membrane tension[6-9], 2. electrophoresis [10] where an electric field is applied across nanotubes using Ag/AgCl electrodes inside gel-plugged pipettes, and 3. by diffusional relaxation from systems with pre-programmed chemical potential. All these transport modes can be combined with confocal microscopy and sensitive APD detectors, for single-molecule interrogation. For example, electrophoretic transport and single-molecule detection of large DNA molecules while confined in the lipid nanotube was achieved [10].

Thus, networks of nanotubes and vesicles serve as a platform to build nanofluidic devices operating with single molecules and particles and offers new opportunities to study chemistry in confined biomimetic compartments. As an example, we demonstrate that a transition from a compact geometry (sphere) to a structured geometry (several spheres connected by nanoconduits) induces an ordinary enzyme-catalyzed reaction to display wave-like properties. The reaction dynamics can be directly controlled by the geometry of the network and such networks can be used to generate various wave-like patterns in product formation. The results have bearing for understanding catalytic reactions in biological systems as well as for designing emerging wet chemical nanotechnological devices.

[1.] Karlsson M, Nolkrantz K, Davidson MJ, Stroemberg A, Ryttsen F, Akerman B, Orwar O. Electroinjection of colloid particles and biopolymers into single unilamellar liposomes and cells for bioanalytical applications. Analytical Chemistry (2000) 72, 5857-5862. [2.] Karlsson A, Karlsson R, Karlsson M, Cans A-S, Stroemberg A, Ryttsen F, Orwar O. Molecular engineering - Networks of nanotubes and containers. Nature (2001) 409, 150-152. [3.] Karlsson M, Sott K, Cans A-S, Karlsson A, Karlsson R, Orwar O. Micropipette-assisted formation of microscopic networks of unilamellar lipid bilayer nanotubes and containers. Langmuir (2001) 17, 6754-6758. [4.] Karlsson M, Sott K, Davidson M, Cans A-S, Linderholm P, Chiu D, Orwar O. Formation of geometrically complex lipid nanotube-vesicle networks of higher-order topologies. Proc. Natnl. Acad. Sci. USA (2002) 99, 11573-11578. [5.] Davidson M, Karlsson M, Sinclair J, Sott K, Orwar O. Nanotube-vesicle networks with functionalized membranes and interiors. Journal of the American Chemical Society (2003) 125, 374-378. [6.] Karlsson R, Karlsson M, Karlsson A, Cans A-S, Bergenholtz J, Akerman B, Ewing AG, Voinova M, Orwar O. Moving-wall-driven flows in nanofluidic systems. Langmuir (2002) 18, 4186-4190. [7.] Karlsson A, Karlsson M, Karlsson R, Sott K, Lundqvist A, Tokarz M, Orwar O. Nanofluidic networks based on surfactant membrane technology. Analytical Chemistry (2003) 75, 2529-2537. [8.] Davidson M, Dommersnes P, Markstroem M, Joanny J-F, Karlsson M, Orwar O. Fluid mixing in growing microscale vesicles conjugated by surfactant nanotubes. Journal of the American Chemical Society (2005) 127, 1251-1257. [9.] Karlsson R, Karlsson A, Orwar O. Formation and transport of nanotube-integrated vesicles in a lipid bilayer network. Journal of Physical Chemistry B (2003) 107, 11201-11207. [10.] Tokarz M, Akerman B, Olofsson J, Joanny J-F, Dommersnes P, Orwar O. Single-file electrophoretic transport and counting of individual DNA molecules in surfactant nanotube Proc. Natnl. Acad. Sci. USA 102, 9127-9132.