Collective Conformations
of DNA Polymers Assembled
on Surface Density Gradients
- Publication date
- Publisher
Abstract
To study dense double-stranded DNA (dsDNA) polymer phases,
we fabricated
continuous density gradients of binding sites for assembly on a photochemical
interface and measured both dsDNA occupancy and extension using evanescent
fluorescence. Despite the abundance of available binding sites, the
dsDNA density saturates after occupation of only a fraction of the
available sites along the gradient. The spatial position at which
the density saturates marks the onset of collective stretching of
dsDNA, a direct manifestation of balancing entropic and excluded-volume
interactions. The methodology presented here offers a new means to
investigate dense dsDNA compartments