Brownian Ratchets: Molecular Separations in Lipid Bilayers Supported on Patterned Arrays

Brownian ratchets use a time-varying asymmetric potential that can be applied to separate diffusing particles or molecules. A new type of Brownian ratchet, a geometrical Brownian ratchet, has been realized. Charged, fluorescently labeled phospholipids in a two-dimensional fluid bilayer were driven i...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 1999-08, Vol.285 (5430), p.1046-1048
Main Authors: van Oudenaarden, Alexander, Boxer, Steven G.
Format: Article
Language:English
Subjects:
4-Chloro-7-nitrobenzofurazan - analogs & derivatives
4-Chloro-7-nitrobenzofurazan - chemistry
4-Chloro-7-nitrobenzofurazan - isolation & purification
Bilayer lipid membranes
Chemical Phenomena
Chemistry
Chemistry, Physical
Diffusion
Electric fields
Electrophoresis
Exact sciences and technology
Fluorescence
Fluorescent Dyes
General and physical chemistry
Geometry
Lipid Bilayers
Lipid membranes
Lipids
Membrane Fluidity
Membrane Proteins - chemistry
Membrane Proteins - isolation & purification
Molecular sieves
Molecules
P branes
Particle diffusion
Particle motion
Phosphatidylethanolamines - chemistry
Phosphatidylethanolamines - isolation & purification
Phosphatidylserines - chemistry
Phosphatidylserines - isolation & purification
Phospholipids
Phospholipids - chemistry
Phospholipids - isolation & purification
Solid-liquid interface
Surface physical chemistry
Temperature
Thermodynamics
Xanthenes
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Description
Summary:Brownian ratchets use a time-varying asymmetric potential that can be applied to separate diffusing particles or molecules. A new type of Brownian ratchet, a geometrical Brownian ratchet, has been realized. Charged, fluorescently labeled phospholipids in a two-dimensional fluid bilayer were driven in one direction by an electric field through a two-dimensional periodic array of asymmetric barriers to lateral diffusion fabricated from titanium oxide on silica. Diffusion spreads the phospholipid molecules in the orthogonal direction, and the asymmetric barriers rectify the Brownian motion, causing a directional transport of molecules. The geometrical ratchet can be used as a continuous molecular sieve to separate mixtures of membrane-associated molecules that differ in electrophoretic mobility and diffusion coefficient.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.285.5430.1046