Enhanced transport of macromolecules in more crowded environments
Fan-Tso Chien1, Po-keng Lin1, Wei Chien1, Yeng-Long Chen1,2,3*
1Physics, Academia Sinica, Taipei, Taiwan
2Physics, National Taiwan University, Taipei, Taiwan
3Chemical Engineering, National Tsing-Hua University, Hsin-chu, Taiwan
* presenting author:Yeng-Long Chen, email:ylchen@gate.sinica.edu.tw
Transport and diffusion of molecules are expected to slow in more crowded systems such as glasses, gels, and intra-cellular fluid. This principle has been exploited in molecular separation techniques
such as gel electrophoresis. We observed enhanced diffusion of DNA molecules in more crowded interactive environments, which contradicts most prior studies finding slower diffusion in crowded non-interacting environments. We designed nano-fabricated post arrays to emulate crowded interactive environments, and the coupling of DNA diffusion with adsorption to the microposts results in more frequent hopping and increased mobility with increasing post density, in contrast to findings of decreased mobility in dense gels and non-attractive nanoposts. The hidden Markov method was applied to identify the hopping probability. We found the apparent free energy barriers to be near thermal energy. Langevin dynamics simulations also confirmed enhanced diffusion in denser arrays.

Keywords: Diffusion, DNA, micropost , nanofluid