Persistence length and scaling properties of single-stranded DNA adsorbed on modiﬁed graphite
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.
Keywords: adsorption ; atomic force microscopy ; biological techniques ; DNA ; graphite ; molecular biophysics ; ATOMIC-FORCE MICROSCOPY ; RADIAL-DISTRIBUTION FUNCTION ; SELF-AVOIDING WALK ; POLYMER-CHAIN ; 2 DIMENSIONS ; MICA SURFACE ; MOLECULES ; FLEXIBILITY ; ADSORPTION ; POLYELECTROLYTES
Record created on 2009-09-07, modified on 2016-08-08