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Updated: Jul 30, 2026

Formation of Biomembrane Microarrays with a Squeegee-based Assembly Method
Published on: May 8, 2014
Brownian ratchets: molecular separations in lipid bilayers supported on patterned arrays
1Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Abstract:
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.
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