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DNA-Surfactant interactions, compaction, condensation, decompaction and phase separation

Dias, Rita LU ; Rosa, Monica LU ; Pais, A A C C; Miguel, Maria LU and Lindman, Björn LU (2004) In Journal of the Chinese Chemical Society 51(3). p.447-469
Abstract
Recent investigations-of the interaction between DNA and alkyltrimethyl ammonium bromides of various chain lengths are reviewed. Several techniques have been used such as phase map determinations, fluorescence microscopy, and electron microscopy. Dissociation of the DNA-surfactant complexes, by the addition of anionic surfactant, has received special attention. Precipitation maps for DNA-cationic surfactant' systems were evaluated by turbidimetry for different salt concentrations, temperatures and surfactant chain lengths. Single-stranded DNA molecules precipitate at lower surfactant concentrations than double-helix ones. It was also observed that these systems precipitate for very low concentrations of both DNA and surfactant, and that... (More)
Recent investigations-of the interaction between DNA and alkyltrimethyl ammonium bromides of various chain lengths are reviewed. Several techniques have been used such as phase map determinations, fluorescence microscopy, and electron microscopy. Dissociation of the DNA-surfactant complexes, by the addition of anionic surfactant, has received special attention. Precipitation maps for DNA-cationic surfactant' systems were evaluated by turbidimetry for different salt concentrations, temperatures and surfactant chain lengths. Single-stranded DNA molecules precipitate at lower surfactant concentrations than double-helix ones. It was also observed that these systems precipitate for very low concentrations of both DNA and surfactant, and that the extension of the two-phase region increases for longer chain surfactants; these observations correlate well with fluorescence microscopy results, monitoring the system at a single molecule level. Dissociation of the DNA-cationic surfactant complexes and a concomitant release of DNA was achieved by addition of anionic surfactants. The unfolding of DNA molecules, previously compacted with cationic surfactant, was shown to be strongly dependent on the anionic surfactant chain length; lower amounts of a longer chain surfactant were needed to release DNA into solution. On the other hand, no dependence on the hydrophobicity of the compacting agent was observed. The structures of the aggregates formed by the two surfactants, after the interaction with DNA, were imaged by cryogenic transmission electron microscopy. It is possible to predict the structure of the aggregates formed by the surfactants, like vesicles, from the phase behaviour of the mixed surfactant systems. The compaction of a medium size polyanion with shorter polycations was furthermore studied by means of Monte Carlo simulations. The polyanion chain suffers a sudden collapse as a function of the condensing agent concentration and of the number of charges on the molecules. Further increase of the concentration gives an increase of the degree of compaction. The compaction was found to be associated with the polycations promoting bridging between different sites of the polyanion. When the total charge of the polycations was lower than that of the polyanion, a significant translational motion of the compacting agent along the polyanion was observed, producing only a small-degree of intrachain segregation. However, complete charge neutralization was not a prerequisite to achieve compacted forms. (Less)
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author
organization
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Contribution to journal
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published
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in
Journal of the Chinese Chemical Society
volume
51
issue
3
pages
447 - 469
publisher
Chinese Chemical Society
external identifiers
  • wos:000222314400001
  • scopus:33646358202
ISSN
2192-6549
language
English
LU publication?
yes
id
019be0c1-3ddc-45e9-aecb-47829f4ff364 (old id 153898)
alternative location
http://nr.stpi.org.tw/ejournal/ChiChemSociety/2004/EJ52-2004-447.pdf
date added to LUP
2007-07-11 09:46:17
date last changed
2017-12-10 03:51:03
@article{019be0c1-3ddc-45e9-aecb-47829f4ff364,
  abstract     = {Recent investigations-of the interaction between DNA and alkyltrimethyl ammonium bromides of various chain lengths are reviewed. Several techniques have been used such as phase map determinations, fluorescence microscopy, and electron microscopy. Dissociation of the DNA-surfactant complexes, by the addition of anionic surfactant, has received special attention. Precipitation maps for DNA-cationic surfactant' systems were evaluated by turbidimetry for different salt concentrations, temperatures and surfactant chain lengths. Single-stranded DNA molecules precipitate at lower surfactant concentrations than double-helix ones. It was also observed that these systems precipitate for very low concentrations of both DNA and surfactant, and that the extension of the two-phase region increases for longer chain surfactants; these observations correlate well with fluorescence microscopy results, monitoring the system at a single molecule level. Dissociation of the DNA-cationic surfactant complexes and a concomitant release of DNA was achieved by addition of anionic surfactants. The unfolding of DNA molecules, previously compacted with cationic surfactant, was shown to be strongly dependent on the anionic surfactant chain length; lower amounts of a longer chain surfactant were needed to release DNA into solution. On the other hand, no dependence on the hydrophobicity of the compacting agent was observed. The structures of the aggregates formed by the two surfactants, after the interaction with DNA, were imaged by cryogenic transmission electron microscopy. It is possible to predict the structure of the aggregates formed by the surfactants, like vesicles, from the phase behaviour of the mixed surfactant systems. The compaction of a medium size polyanion with shorter polycations was furthermore studied by means of Monte Carlo simulations. The polyanion chain suffers a sudden collapse as a function of the condensing agent concentration and of the number of charges on the molecules. Further increase of the concentration gives an increase of the degree of compaction. The compaction was found to be associated with the polycations promoting bridging between different sites of the polyanion. When the total charge of the polycations was lower than that of the polyanion, a significant translational motion of the compacting agent along the polyanion was observed, producing only a small-degree of intrachain segregation. However, complete charge neutralization was not a prerequisite to achieve compacted forms.},
  author       = {Dias, Rita and Rosa, Monica and Pais, A A C C and Miguel, Maria and Lindman, Björn},
  issn         = {2192-6549},
  language     = {eng},
  number       = {3},
  pages        = {447--469},
  publisher    = {Chinese Chemical Society},
  series       = {Journal of the Chinese Chemical Society},
  title        = {DNA-Surfactant interactions, compaction, condensation, decompaction and phase separation},
  volume       = {51},
  year         = {2004},
}