Shandong Science ›› 2019, Vol. 32 ›› Issue (4): 94-100.doi: 10.3976/j.issn.1002-4026.2019.04.013

• Other Research Article • Previous Articles     Next Articles

Effect of divalent ions on the polyelectrolyte chains at different pH

LI Shu-hang, ZHU Ze-dong, XU Zi-yan, YANG Guang-can*   

  1. School of Mathematics and Electronic Information Engineering, Wenzhou University, Wenzhou 325035, China
  • Received:2019-04-15 Online:2019-08-20 Published:2019-08-07

Abstract: In this study, the effect of divalent counterions on the conformational change of the semi-flexible polyelectrolyte chains was investigated at different pH based on Langevin’s dynamics. Polyelectrolyte is represented by a coarse-grained bead spring model, with the radius of gyration (Rg) remaining almost constant at pH-pK>0. Rg reduces and the polyelectrolyte chain shrinks as the value of pH-pK decreases. Meanwhile, in the experiment, the atomic force microscopy images of the DNA mediated by Mg2+ were obtained in different pH environments to denote that the DNA remained in a free and loose state in neutral and weakly acidic environments. At pH<4, i.e., strong acidity, DNA was gradually condensed into a spherical shape and stabilized. Further, the experimental result agrees with the simulation results.

Key words: Langevin’s dynamics, counter ion, polyelectrolyte, pH, DNA

CLC Number: 

  • Q71