Autonomic Molecular Transport by Polymer Films Containing Programmed Chemical Potential Gradients

作者：Zhang Chunjie; Sitt Amit; Koo Hyung Jun; Waynant Kristopher V; Hess Henry; Pate Brian D; Braun Paul V^*

来源：Journal of the American Chemical Society, 2015, 137(15): 5066-5073.

DOI：10.1021/jacs.5b00240

Materials which induce molecular motion without external input offer unique opportunities for spatial manipulation of molecules. Here, we present the use of polyacrylamide hydrogel films containing built-in chemical gradients (enthalpic gradients) to direct molecular transport. Using a cationic tertiary amine gradient, anionic molecules were directionally transported up to several millimeters. A 40-fold concentration of anionic molecules dosed in aerosol form on a substrate to a small region at the center of a radially symmetric cationic gradient was observed. The separation of mixtures of charged dye molecules was demonstrated using a boronic acid-to-cationic gradient where one molecule was attracted to the boronic acid end of the gradient, and the other to the cationic end of the gradient. Theoretical and computational analysis provides a quantitative description of such anisotropic molecular transport, and reveals that the gradient-imposed drift velocity is in the range of hundreds of nanometers per second, comparable to the transport velocities of biomolecular motors. This general concept of enthalpy gradient-directed molecular transport should enable the autonomous processing of a diversity of chemical species.

• 出版日期2015-4-22