Gold‐Cluster Degradation by the Transition of B‐DNA into A‐DNA and the Formation of Nanowires

Abstract

Interactions between metals and biomacromolecules including proteins, polysaccharides, and nucleic acids are important since they can be essential for a number of natural and industrial phenomena. These range from interactions of highly specific metal cofactors with particular proteins [1] to biosorption of heavy metals by polysaccharide hydrogels.[2]The unique features of DNA have been exploited in the development of novel materials, especially in the areas of medicine and nanotechnology. Classical research concerning antitumor drugs has focussed on the interactions of platinumor ruthenium-containing compounds with the major or minor grooves of polynucleotides. [3][4][5][6] There is a tremendous interest in the use of DNA in nanotechnology as a positioning template for the immobilization of metal nanoclusters with view to future applications in the construction of nanoelectronic devices. [7][8][9][10][11] Herein we report the interaction of Au 55 nanoclusters with the major grooves of B-DNA. The Au 55 clusters are degraded to Au 13 clusters by the transition of B-DNA into A-DNA in ultrahigh vacuum, and the resulting shrinkage of the major grooves. We have performed molecular-dynamics simulations and provided further information on the mechanism by which wires of Au 13 clusters form, and attempt to explain the interwire separation of 0.5 nm.

A Dual Effect of Au-Nanoparticles on Nucleic Acid Cholesteric Liquid-Crystalline Particles

“…Later it was shown that an assembly of the Au-nanoparticles is accompanied by formation of planar superstructure consisting of repetitive neighboring linear DNA molecules and Aunanopartices. These results unequivocally show that linear, rigid, ds DNA molecules after interaction with Aunanoparticles form planar superstructures of type (…-Au-DNA-Au-DNA-Au-DNA-Au-…), despite the anisotropic properties of initial ds DNA molecules [4,[26][27][28][29].…”

“…For instance, it was suggested that biological effect of Au-nanoparticles on spatially organized double-stranded (ds) DNA structures in vitro and in vivo is similar to the effect of mutagenic molecules [2,3]. One can stress that the interaction of metal nanoparticles with native single-or double-stranded nucleic acid molecules is a well-known phenomenon [4]. Although, the cytotoxicity of Au-nanoparticles in vitro and in vivo has been examined by several research groups, no general conclusion can be drawn at present [5][6][7][8].…”

Cytotoxicity of gold nanoclusters in human liver cancer cells

“…11 Liu et al 12 found that bare Au 55 (Ph 2 PC 6 H 4 SO 3 H) 12 Cl 6 combined irreversibly into the major grooves of B-DNA (depth: 0.9 nm; length: 1.43 nm) due to their distinct size of 1.4 nm. Subsequently, Tsoli et al 13 reported that the IC 50 (half maximal inhibitory concentration) of Au 55 (Ph 2 PC 6 H 4 SO 3 H) 12 Cl 6 was approximately 180 times lower than the anticancer drug cisplatin in BLM melanoma cells and more than 200 times lower in the MV3 cell line.…”

On the application potential of gold nanoparticles in nanoelectronics and biomedicine

“…Along with this, the reduced toxicity, which was observed in the presence of excess ligand (TPPMS), is a consequence of preventing ligand exchange by interacting the gold cluster core with intracellular biological compounds. Liu et al 2003).…”