Yuri M. Yevdokimov

Adjustable 'cross-linking' of neighboring DNA molecules in liquid-crystalline dispersions through (daunomycin-copper) polymeric chelate complexes.

The interaction of daunomycin molecules with double-stranded DNA in the liquid-crystalline state was investigated. It was shown that at a certain extent of daunomycin binding a change of the mechanism of anthracycline orientation with reference to the DNA chain occurs. This is testified by the alteration of the sense of spatial packing of the DNA molecules in liquid-crystalline dispersions formed as a result of phase separation in poly(ethyleneglycol)-containing solutions, as well as by the onset of the reaction of daunomycin with divalent copper ions. Using this reaction, polymeric (daunomycin-copper) chelate cross-links between the DNA molecules fixed in the liquid-crystalline dispersions were formed. The length of such cross-links as adjusted by the distance between the DNA molecules, which, in turn, depends on the concentration of poly(ethyleneglycol) used for phase separation. The above molecular building mechanism may lead to new interesting applications.

Nanotechnology and Nucleic Acids

The peculiarities of two approaches in the nanodesign based on the double-stranded nucleic acid molecules are considered. Main attention is devoted to the formation and properties of nanoconstructions based on the double-stranded DNA molecules and the complexes with chitosan, fixed in the spatial structure of particles of their cholesteric liquidcrystalline dispersions, and cross-linked by artificial nanobridges consisting of alternating copper ions and daunomycin molecules. In contrast to initial DNA liquid-crystalline particles, the structure of resulting nanoconstruction is not “liquidcrystalline” any more; rather it is rigid, crystal-like, three-dimensional structure. The formed nanoconstructions possess the unique spatial and optical properties; this opens a gate for their application in biotechnology and medicine.