Structural effects induced by gold nanoparticles in particles of cholesteric liquid-crystalline dispersion of double-stranded nucleic acids

Gold (Au) nanoparticles of diameter ~2 nm (but not 5 or 15 nm) were capable of incorporating effectively into quasi-nematic layers of particles of cholesteric liquid-crystalline dispersions (CLCD) formed by double-stranded nucleic acids of various families [B-form DNA, A-form poly(I) × poly(C)]. A study of the properties of CLCD particles treated with Au nanoparticles by various physicochemical methods demonstrated that incorporation of Au nanoparticles into quasi-nematic layers of these particles resulted in two effects. First, it caused rearrangement of the spatial cholesteric structure of LC dispersion particles that was accompanied by a decrease in the amplitude of the anomalous band in the circular dichroism spectrum of the corresponding initial CLCD. Second, it induced Au cluster formation within the LC particles that was accompanied by the appearance of a surface plasmon resonance band in the visible spectral region. It was possible that these structural effects were responsible for the genotoxicity of the Au nanoparticles.