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Factors Controlling Phase Separation in Water-Salt Solutions of DNA and Polycations.

Izumrudov, Vladimir LU ; Wahlund, Per-Olof LU ; Gustavsson, Per-Erik LU ; Larsson, Per-Olof LU and Galaev, Igor LU (2003) In Langmuir 19(11). p.4733-4739
Abstract
Factors affecting phase separation in water-salt solutions of polyelectrolyte complexes (PECs), formed by DNA and integral or pendant polycations with a quaternary amino group in every monomer unit, have been studied. When no salt was added, quantitative DNA precipitation occurred at a stoichiometric charge ratio, = [+]/[-] 1. In DNA mixtures with poly(N,N'-dimethyldiallylammonium chloride) (PDMDAAC, a pendant polycation), insoluble PECs formed in the range 0.7 < < 2. This suggests the formation of soluble, negatively charged PECs at 0 < < 0.7 and soluble, positively charged PECs at > 2. For different aliphatic ionene bromides (integral polycations), the range of corresponding to insoluble PECs was significantly broader,... (More)
Factors affecting phase separation in water-salt solutions of polyelectrolyte complexes (PECs), formed by DNA and integral or pendant polycations with a quaternary amino group in every monomer unit, have been studied. When no salt was added, quantitative DNA precipitation occurred at a stoichiometric charge ratio, = [+]/[-] 1. In DNA mixtures with poly(N,N'-dimethyldiallylammonium chloride) (PDMDAAC, a pendant polycation), insoluble PECs formed in the range 0.7 < < 2. This suggests the formation of soluble, negatively charged PECs at 0 < < 0.7 and soluble, positively charged PECs at > 2. For different aliphatic ionene bromides (integral polycations), the range of corresponding to insoluble PECs was significantly broader, mainly due to the poor ability of the ionenes to form soluble, positively charged PECs. The range was also relatively broad for poly(N-ethyl-4-vinylpyridinium bromide) (a pendant polycation) and became broader with decreasing degree of polymerization of the polycation. The formation of insoluble PECs was favored by the addition of salt (NaCl), and the effect was more pronounced when decreasing the relative content of the solubilizing component, i.e., the nucleic acid at < 1 and the polycation at > 1. At moderate ionic strength, 0.12 M < [NaCl] < 0.6 M, quantitative precipitation of DNA was attained by addition of PDMAAC in the whole region studied: 1 < < 4.5. The data obtained strongly suggest that phase separation in solutions of DNA-containing PECs follows general rules revealed by studying PECs formed by flexible vinyl polyanions. However, the high rigidity of the DNA double helix appears to be responsible for the key feature revealed in the phase diagrams, i.e., significant broadening of the region for insoluble PECs at the expense of the region in which soluble DNA-containing PECs are formed. This feature may severely limit the application of DNA-containing PECs in medicine and biology but could be beneficial in the development of simple and effective procedures for DNA separation in biotechnology. (Less)
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organization
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Contribution to journal
publication status
published
subject
in
Langmuir
volume
19
issue
11
pages
4733 - 4739
publisher
The American Chemical Society
external identifiers
  • wos:000183136900033
  • scopus:0038242889
ISSN
0743-7463
DOI
language
English
LU publication?
yes
id
660c3ef1-d4fa-4a07-8ce7-cbef394e78da (old id 128613)
date added to LUP
2007-07-02 11:48:28
date last changed
2018-05-29 09:51:44
@article{660c3ef1-d4fa-4a07-8ce7-cbef394e78da,
  abstract     = {Factors affecting phase separation in water-salt solutions of polyelectrolyte complexes (PECs), formed by DNA and integral or pendant polycations with a quaternary amino group in every monomer unit, have been studied. When no salt was added, quantitative DNA precipitation occurred at a stoichiometric charge ratio, = [+]/[-] 1. In DNA mixtures with poly(N,N'-dimethyldiallylammonium chloride) (PDMDAAC, a pendant polycation), insoluble PECs formed in the range 0.7 &lt; &lt; 2. This suggests the formation of soluble, negatively charged PECs at 0 &lt; &lt; 0.7 and soluble, positively charged PECs at &gt; 2. For different aliphatic ionene bromides (integral polycations), the range of corresponding to insoluble PECs was significantly broader, mainly due to the poor ability of the ionenes to form soluble, positively charged PECs. The range was also relatively broad for poly(N-ethyl-4-vinylpyridinium bromide) (a pendant polycation) and became broader with decreasing degree of polymerization of the polycation. The formation of insoluble PECs was favored by the addition of salt (NaCl), and the effect was more pronounced when decreasing the relative content of the solubilizing component, i.e., the nucleic acid at &lt; 1 and the polycation at &gt; 1. At moderate ionic strength, 0.12 M &lt; [NaCl] &lt; 0.6 M, quantitative precipitation of DNA was attained by addition of PDMAAC in the whole region studied: 1 &lt; &lt; 4.5. The data obtained strongly suggest that phase separation in solutions of DNA-containing PECs follows general rules revealed by studying PECs formed by flexible vinyl polyanions. However, the high rigidity of the DNA double helix appears to be responsible for the key feature revealed in the phase diagrams, i.e., significant broadening of the region for insoluble PECs at the expense of the region in which soluble DNA-containing PECs are formed. This feature may severely limit the application of DNA-containing PECs in medicine and biology but could be beneficial in the development of simple and effective procedures for DNA separation in biotechnology.},
  author       = {Izumrudov, Vladimir and Wahlund, Per-Olof and Gustavsson, Per-Erik and Larsson, Per-Olof and Galaev, Igor},
  issn         = {0743-7463},
  language     = {eng},
  number       = {11},
  pages        = {4733--4739},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Factors Controlling Phase Separation in Water-Salt Solutions of DNA and Polycations.},
  url          = {http://dx.doi.org/},
  volume       = {19},
  year         = {2003},
}