American Chemical Society, Journal of Physical Chemistry B (Soft Condensed Matter and Biophysical Chemistry), 15(113), p. 4987-4990, 2009
DOI: 10.1021/jp8097318
Full text: Download
The morphology of circular DNA deposited from a solution on the mica surface is analyzed from the power spectrum density (PSD) of the atomic force microscopy (AFM) images. Sample morphology is modulated in a broad range of concentration C from isolated molecules to highly entangled networks. DNA exhibits a multiaffine behavior with two correlation length scales: the persistence length P which remains constant ( approximately 50 nm) within the C range and the intermolecular distance xi which exhibits a decay with increasing C. Applying a diffusion based model in which xi scales as xi approximately D(-0.25).C(-0.5), we extracted the DNA diffusion coefficient D approximately 2 x 10(-7) cm(2)/s. This value is consistent with a high-molecular-weight plasmid DNA supercoiled in the solution.