Measurement of DNA morphological parameters at highly entangled regime on surfaces.
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.
Calò
Annalisa
A
CNR-Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via Gobetti 101 - 40129 Bologna, Italy.
Stoliar
Pablo
P
Bystrenova
Eva
E
Valle
Francesco
F
Biscarini
Fabio
F
D000538:Aluminum Silicates / Q000737:chemistry*; D004270:DNA, Circular / Q000032:analysis* / Q000737:chemistry*; D004058:Diffusion; D018625:Microscopy, Atomic Force; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D010316:Particle Size; D013499:Surface Properties
D000538:Aluminum Silicates; D004270:DNA, Circular; C011934:mica