A dynamic light scattering study of a 2311 base pair DNA restriction fragment

Sorlie, Susan S.; Pecora, R.

doi:10.1021/ma00183a039

Cited by 77 publications

(82 citation statements)

References 18 publications

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“…3,4,[17][18][19][20][21][22][23][24] The diffusion coefficients measured in the present work were corrected to the standard temperature of 20°C using eq. (7).…”

Section: Resultsmentioning

confidence: 99%

Measuring the translational diffusion coefficients of small DNA molecules by capillary electrophoresis

et al. 2001

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“…3,4,[17][18][19][20][21][22][23][24] The diffusion coefficients measured in the present work were corrected to the standard temperature of 20°C using eq. (7).…”

Section: Resultsmentioning

confidence: 99%

Measuring the translational diffusion coefficients of small DNA molecules by capillary electrophoresis

et al. 2001

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“…While there has been a number of DLS reports on the properties of DNA solutions (see, for example Refs. [71][72][73][74]), studies involving interactions between DNA and cationic amphiphiles are in a very limited number [18,24,75].…”

Section: A Dynamic Light Scattering Studymentioning

confidence: 99%

DNA and surfactants in bulk and at interfaces

Dias

Pais

Miguel

et al. 2004

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Recent investigations of the DNA interactions with cationic surfactants and catanionic mixtures are reviewed. Several techniques have been used such as fluorescence microscopy, dynamic light scattering, electron microscopy, and Monte Carlo simulations.The conformational behaviour of large DNA molecules in the presence of cationic surfactant was followed by fluorescence microscopy and also by dynamic light scattering. These techniques were in good agreement and it was possible to observe a discrete transition from extended coils to collapsed globules and their coexistence for intermediate amphiphile concentrations. The dependence on the surfactant alkyl chain was also monitored by fluorescence microscopy and, as expected, lower concentrations of the more hydrophobic surfactant were required to induce DNA compaction, although an excess of positive charges was still required.Monte Carlo simulations on the compaction of a medium size polyanion with shorter polycations were performed. The polyanion chain suffers a sudden collapse as a function of the concentration of condensing agent, and of the number of charges on the polycation molecules. Further increase in the concentration increases 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, which can explain the excess of positive charges necessary to compact DNA.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.Studies on the interactions between DNA and catanionic mixtures were also performed. It was observed that DNA does not interact with negatively charged vesicles, even though they carry positive amphiphiles; however, in the presence of positively charged vesicles, DNA molecules compact and adsorb on their surface.Finally Monte Carlo simulations were performed on the adsorption of a polyelectrolyte on catanionic surfaces. It was observed that the mobile charges in the surface react to the presence of the polyelectrolyte enabling a strong degree of adsorption even though the membrane was globally neutral. Our observati...

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“…Diffusion coefficients were determined from the peak maxima on CONTIN distributions. As has been previously discussed, 44,45 peak widths obtained from CONTIN analysis depend quite strongly on the noise, which can induce peak broadening. In contrast, positions of the peak maxima on CONTIN distributions are much less sensitive to small changes in noise level.…”

Section: G("( K T )mentioning

confidence: 85%