Anatoly Zinchenko

DNA cross-linked hydrogel was used as a matrix for synthesis of gold nanoparticles. DNA possesses a strong affinity to transition metals such as gold, which allows for the concentration of Au precursor inside a hydrogel. Further reduction of HAuCl4 inside DNA hydrogel yields well dispersed, non-aggregated spherical Au nanoparticles of 2-3 nm size. The average size of these Au nanoparticles synthesized in DNA hydrogel is the smallest reported so far for in-gel metal nanoparticles synthesis. DNA h

Monodisperse silver rings with nanometer-scale diameters (see Figure) are produced due to the ability of DNA to organize into toroidal condensates with well-defined shapes and sizes upon its interaction with multications. Silver ions can bind to the residual negative surface charge of condensed DNA, and are then reduced to silver metal to yield DNA toroids coated with a thin silver metal shell.

We elaborated a versatile experimental model of chromatin which consists of a single chain of long duplex DNA that interacts with well-defined cationic nanoparticles of various sizes. We found that the DNA compaction by nanoparticles is stepwise and progressive at the single-chain level. It is controlled by the ability of DNA to wrap nanoparticles, which is more efficient for larger particles and, similar to DNA-histone interaction, is optimal at a physiological salt concentration.

The compaction of long duplex DNA by cationic nanoparticles (NP) used as a primary model of histone core particles has been investigated. We have systematically studied the effect of salt concentration, particle size, and particle charge by means of single-molecule observations-fluorescence microscopy (FM) and transmission electron microscopy (TEM)-and molecular dynamics (MD) simulations. We have found that the large-scale DNA compaction is progressive and proceeds through the formation of beads

DNA interaction with quaternary diammonium dications, R(CH(3))(2)N(+)(CH(2))(n)N(+)(CH(3))(2)R, having various intercharge distances, lengths, and branching, and the chemical nature of the hydrophobic substituents were investigated by fluorescent microscopy and circular dichroism (CD) spectroscopy to reveal their structural specificity for binding to DNA. The conformational behavior of DNA was found to be highly sensitive to the structure of the dications with separated charges. The distance bet

Intrachain segregation in single DNA molecules induced by quaternary ammonium dications was studied. By means of fluorescent and electron microscopy, it was found that variations in the chemical structure of condensing agents provide one with the opportunity to control the average amount of intrachain segregation centers on the DNA single chain. The manner of interaction between the diammonium molecules was considered to be the key factor for controlling the morphology of the partially collapsed

DNA-chitosan (DNA-CS) hydrogel was prepared by in situ complexation between oppositely charged DNA and chitosan polyelectrolytes via electrostatic cross-linking to study its adsorption characteristics. The DNA-chitosan hydrogel matrix contains (i) cationic (NH₃⁺) and anionic (PO₄^-) sites for electrostatic binding with ionic species, (ii) -OH and -NH₂ groups and heteroaromatic DNA nucleobases for chelation of heavy metal ions, and (iii) DNA d

Up to the present, DNA structural transitions caused by cationic polymers as well as in concentrated solutions of neutral polymers are well documented, while a little is known about DNA interaction with like-charge species. Herein, changes in the structure of DNA induced by anionic nanoparticles of different sizes (20-130 nm) were investigated by combining single-molecule DNA fluorescent microscopy, to monitor the conformational dynamics of long-chain DNA, with spectroscopic methods, to gain ins