Brownian Motion of DNA Confined Within a Two-Dimensional Array
Dmytro Nykypanchuk,
Helmut H. Strey,*
David A. Hoagland*
Linear DNA molecules are visualized while undergoing
Brownian motion inside media patterned with molecular-sized spatial
constraints. The media, prepared by colloidal templating, trap the
macromolecules within a two-dimensional array of spherical cavities
interconnected by circular holes. Across a broad DNA size range,
diffusion does not proceed by the familiar mechanisms of reptation or
sieving. Rather, because of their inherent flexibility, DNA molecules
strongly localize in cavities and only sporadically "jump" through
holes. Jumping closely follows Poisson statistics. By reducing DNA's configurational freedom, the holes act as molecular
weight-dependent entropic barriers. Sterically constrained
macromolecular diffusion underlies many separation methods and assumes
an important role in intracellular and extracellular transport.
Department of Polymer Science and Engineering, University of
Massachusetts Amherst, Amherst, MA 01003, USA.
*
To whom correspondence should be addressed.
E-mail: strey{at}mail.pse.umass.edu (H.H.S.) and
dah{at}neurotica.pse.umass.edu (D.A.H.).
