title: Persistence length and scaling properties of single-stranded DNA adsorbed on modified graphite.
abstract: We have characterized the polymer physics of single-stranded DNA (ssDNA) using atomic force microscopy. The persistence length l(p) of circular ssDNA adsorbed on a modified graphite surface was determined independently of secondary structure. At a very low ionic strength we obtained l(p)=9.1 nm from the bond correlation function. Increasing the salt concentration lead to a decrease in l(p); at 1 mM NaCl we found l(p)=6.7 nm, while at 10 mM NaCl a value l(p)=4.6 nm was obtained. The persistence length was also extracted from the root-mean-square end-to-end distance and the end-to-end distance distribution function. Finally, we have investigated the scaling behavior using the two latter quantities, and found that on long length scales ssDNA behaves as a two-dimensional self-avoiding walk.
authors.affiliation: Laboratoire de Physique de la Matière Vivante, Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Kristian
authors.initials: K
authors.lastname: Rechendorff
authors.forename: Guillaume
authors.initials: G
authors.lastname: Witz
authors.forename: Jozef
authors.initials: J
authors.lastname: Adamcik
authors.forename: Giovanni
authors.initials: G
authors.lastname: Dietler
mesh_terms: D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods*; D015999:Multivariate Analysis; D009690:Nucleic Acid Conformation; D012492:Salts
chemical_list: D004277:DNA, Single-Stranded; D012492:Salts; D006108:Graphite; D004247:DNA