A new nanobiomaterial: particles of liquid-crystalline DNA dispersions with embedded clusters of gold nanoparticles

Abstract

The effect of gold (Au) nanoparticles with an average size of about 2 nm on double-stranded DNA cholesteric liquid-crystal dispersion (CLCD) particles has been studied. Treatment of DNA CLCD by Au nanoparticles results in two effects: a “disturbance” of the spatial structure of dispersion particles and the induction of the cholesteric → nematic phase transition, as well as the formation of 40.5–53.0 nm linear clusters of Au nanoparticles between neighboring DNA molecules. The efficiency of formation of these clusters and their size depend on the solution properties. Clusters of Au nanoparticles can crosslink neighboring DNA molecules, thus forming “rigid” DNA CLCD particles. The average size of rigid DNA CLCD particles is 450–500 nm, and their height does not exceed 300 nm. Thus, the effect of Au nanoparticles on DNA CLCD leads to the formation of nanobiomaterial in which clusters of Au nanoparticles are formed between DNA molecules fixed in the spatial structure of dispersion particles. This nanobiomaterial has new physicochemical properties (such as a lack of abnormal optical activity and the presence of linear clusters of Au nanoparticles in the structure of DNA CLCD particles, via which the interaction between neighboring DNA molecules is implemented); as a result, it differs from standard nanobiomaterials based on double-stranded DNA molecules.