title: Macroscopic transport by synthetic molecular machines.
abstract: Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with-and perform physical tasks in-the macroscopic world represents a significant hurdle for molecular nanotechnology. Here we describe a wholly synthetic molecular system that converts an external energy source (light) into biased brownian motion to transport a macroscopic cargo and do measurable work. The millimetre-scale directional transport of a liquid on a surface is achieved by using the biased brownian motion of stimuli-responsive rotaxanes ('molecular shuttles') to expose or conceal fluoroalkane residues and thereby modify surface tension. The collective operation of a monolayer of the molecular shuttles is sufficient to power the movement of a microlitre droplet of diiodomethane up a twelve-degree incline.
authors.affiliation: School of Chemistry, University of Edinburgh, UK.
authors.forename: José
authors.initials: J
authors.lastname: Berná
authors.forename: David A
authors.initials: DA
authors.lastname: Leigh
authors.forename: Monika
authors.initials: M
authors.lastname: Lubomska
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Mendoza
authors.forename: Emilio M
authors.initials: EM
authors.lastname: Pérez
authors.forename: Petra
authors.initials: P
authors.lastname: Rudolf
authors.forename: Gilberto
authors.initials: G
authors.lastname: Teobaldi
authors.forename: Francesco
authors.initials: F
authors.lastname: Zerbetto
mesh_terms: D032701:Biomimetics / Q000379:methods*; D008422:Materials Testing; D020409:Molecular Motor Proteins / Q000737:chemistry*; D009038:Motion; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D043862:Rotaxanes / Q000032:analysis / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D020409:Molecular Motor Proteins; D043862:Rotaxanes