Melting of columnar hexagonal DNA liquid crystals

Kassapidou, K.; Maarel, Johan R. C. van der

doi:10.1007/s100510050337

Cited by 19 publications

(36 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5 Here, we report the DNA volume fraction is increased. Before the appearance length, ionic strength, and counterion species depenw kT Å Ae 0 k x sin f (1) dence of the cholesteric-isotropic (C-I) phase transition.…”

Section: Introductionmentioning

confidence: 82%

Liquid crystal formation in DNA fragment solutions

et al. 1998

Self Cite

View full text Add to dashboard Cite

The critical volume fractions pertaining to the formation of DNA liquid crystals were obtained from polarization microscopy, 31 P-nmr, and phase separation experiments. The DNA length (approximately one to two times the persistence length 50 nm), ionic strength, and counterion variety dependencies are reported. The cholesteric-isotropic transition is interpreted in terms of the coexistence equations, which are derived from the solution free energy including orientational entropy and excluded volume effects. With the wormlike chain as reference system, the electrostatic contribution to the free energy is evaluated as a thermodynamic perturbation in the second virial approximation with a Debye-Hu ¨ckel potential of mean force. The hard core contribution has been evaluated with scaled particle theory and/or a simple generalization of the Carnahan-Starling equation of state for hard spheres. For sufficiently high ionic strengths, the agreement is almost quantitative. At lower amounts of added salt deviations are observed, which are tentatively attributed to counterion screening effects. The contour length dependence agrees with a DNA persistence length 50 nm.

show abstract

Section: Introductionmentioning

confidence: 82%

Liquid crystal formation in DNA fragment solutions

et al. 1998

Self Cite

View full text Add to dashboard Cite

show abstract

“…As the density of the DNA-assembly is further decreased, the intermolecular interactions would grow ever weaker, until, finally, thermal motion would destroy any lattice ordering in the system. At this point, the lattice would then completely melt into a liquid-like isotropic phase [37].…”

Section: Discussionmentioning

confidence: 99%

Statistical mechanics of columnar DNA assemblies

Wynveen¹,

Lee²,

Kornyshev³

2005

Eur. Phys. J. E

View full text Add to dashboard Cite

Many physical systems can be mapped onto solved or "solvable" models of magnetism. In this work, we have mapped the statistical mechanics of columnar phases of ideally helical rigid DNA--subject to the earlier found unusual, frustrated pair potential (A.A. Kornyshev, S. Leikin, J. Chem. Phys. 107, 3656 (1997))--onto an exotic, unknown variant of the XY model on a fixed or restructurable lattice. Here, the role of the "spin" is played by the azimuthal orientation of the molecules. We have solved this model using a Hartree-Fock approximation, ground-state calculations, and finite-temperature Monte Carlo simulations. We have found peculiar spin order transitions, which may also be accompanied by positional restructuring, from hexagonal to rhombohedric lattices. Some of these have been experimentally observed in dense columnar aggregates. Note that DNA columnar phases are of great interest in biophysical research, not only because they are a useful in vitro tool for the study of DNA condensation, but also since these structures have been detected in living matter. Within the approximations made, our study provides insight into the statistical mechanics of these systems.

show abstract

“…In a related problem-the melting of closepacked hexagonal DNA crystals under zero stressundulation theory 20 agrees well with experiment. 21 Computer simulations of fibers modeled at the atomic level seem a long way off. For the sake of consistency, the quenched state would have to be simulated a priori and this is probably quite difficult to achieve.…”

Section: ͔mentioning

confidence: 99%

Microfibrillar buckling within fibers under compression

Odijk

1998

The Journal of Chemical Physics

View full text Add to dashboard Cite

A tentative theory is presented of microfibrillar buckling within compressed fibers. A quantitative harmonic analysis is given of the semiclassical buckling of a clamped stiff chain; the influence of thermal undulations is incorporated in Euler buckling. A scaling analysis including entropy allows one to understand semiclassical buckling. The buckling of a microfibril within a fibrous environment is analyzed in two limits: ͑a͒ when the fiber is incompressible; ͑b͒ when the matrix is assumed to be a fixed harmonic potential. In the latter case, a network of microfibrils may melt at high enough compression before the usual buckling occurs. We also study the renormalization of the confining potential by long-range elastic fields. A provisional comparison with experimental studies on macroscopic failure is given.

show abstract

Melting of columnar hexagonal DNA liquid crystals

Cited by 19 publications

References 1 publication

Liquid crystal formation in DNA fragment solutions

Liquid crystal formation in DNA fragment solutions

Statistical mechanics of columnar DNA assemblies

Microfibrillar buckling within fibers under compression

Contact Info

Product

Resources

About