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Electrostatic attraction between DNA and a cationic surfactant aggregate. The screening effect of salt

Leal, Cecilia LU ; Moniri, Elham LU ; Pegado, Luis LU and Wennerström, Håkan LU (2007) In The Journal of Physical Chemistry Part B 111(21). p.5999-6005
Abstract
Anionic DNA and cationic surfactants form charge neutral complexes that contain finite amounts of water. There is a strong electrostatic attraction between the oppositely charged species, and the finite swelling is caused by an opposing repulsive force. Adding NaCl to the complexes provides an opportunity to modulate the strength of the electrostatic attraction. The thermodynamics of the isothermal swelling process has been experimentally characterized using a calorimetric technique monitoring both the free energy and the enthalpy. The experimental results are quantitatively analyzed in calculations using the Poisson-Boltzmann equation to describe the electrostatic effects. The main findings are as follows: (i) Addition of salt results in... (More)
Anionic DNA and cationic surfactants form charge neutral complexes that contain finite amounts of water. There is a strong electrostatic attraction between the oppositely charged species, and the finite swelling is caused by an opposing repulsive force. Adding NaCl to the complexes provides an opportunity to modulate the strength of the electrostatic attraction. The thermodynamics of the isothermal swelling process has been experimentally characterized using a calorimetric technique monitoring both the free energy and the enthalpy. The experimental results are quantitatively analyzed in calculations using the Poisson-Boltzmann equation to describe the electrostatic effects. The main findings are as follows: (i) Addition of salt results in an increased swelling at a given water activity. (ii) The effect of the salt can be quantitatively modeled on the basis of the Poisson-Boltzmann equation with a dielectric description of the water. (iii) There exists a short-range repulsive force between DNA double helices and surfactant aggregates. (iv) Solid NaCl dissolves in the complex at water activities in the range 0.5-0.6 rather than at 0.74 as in a saturated aqueous solution. (v) The heat of solution of NaCl in the complexes is around +1.6 +/- 0.5 kJ/mol, surprisingly close to the values found for the dissolution into bulk aqueous solutions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
111
issue
21
pages
5999 - 6005
publisher
The American Chemical Society
external identifiers
  • wos:000246695100026
  • scopus:34250345681
ISSN
1520-5207
DOI
10.1021/jp065358h
language
English
LU publication?
yes
id
a9fb02d7-96d6-4d70-a197-d96f828320dd (old id 663000)
date added to LUP
2007-12-14 13:33:01
date last changed
2017-01-01 07:13:47
@article{a9fb02d7-96d6-4d70-a197-d96f828320dd,
  abstract     = {Anionic DNA and cationic surfactants form charge neutral complexes that contain finite amounts of water. There is a strong electrostatic attraction between the oppositely charged species, and the finite swelling is caused by an opposing repulsive force. Adding NaCl to the complexes provides an opportunity to modulate the strength of the electrostatic attraction. The thermodynamics of the isothermal swelling process has been experimentally characterized using a calorimetric technique monitoring both the free energy and the enthalpy. The experimental results are quantitatively analyzed in calculations using the Poisson-Boltzmann equation to describe the electrostatic effects. The main findings are as follows: (i) Addition of salt results in an increased swelling at a given water activity. (ii) The effect of the salt can be quantitatively modeled on the basis of the Poisson-Boltzmann equation with a dielectric description of the water. (iii) There exists a short-range repulsive force between DNA double helices and surfactant aggregates. (iv) Solid NaCl dissolves in the complex at water activities in the range 0.5-0.6 rather than at 0.74 as in a saturated aqueous solution. (v) The heat of solution of NaCl in the complexes is around +1.6 +/- 0.5 kJ/mol, surprisingly close to the values found for the dissolution into bulk aqueous solutions.},
  author       = {Leal, Cecilia and Moniri, Elham and Pegado, Luis and Wennerström, Håkan},
  issn         = {1520-5207},
  language     = {eng},
  number       = {21},
  pages        = {5999--6005},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Electrostatic attraction between DNA and a cationic surfactant aggregate. The screening effect of salt},
  url          = {http://dx.doi.org/10.1021/jp065358h},
  volume       = {111},
  year         = {2007},
}