Double-stranded DNA fixed in a cholesteric liquid-crystalline dispersion was used for generating an ordered supramolecular structure in the presence of anthracycline and copper (II) ions. The structure is stable in a water-salt solution and does not require poly(ethyleneglycol).The ordered network can be immobilized on the surface of a polymeric film, and may collapse in the presence of biologically and pharmacologically relevant compounds. Accordingly, the DNA-based liquid-crystalline network represents the basis to obtain novel highly sensitive biosensing units.

The possibility of using the dissipation mode in high resolution atomic force microscopy is dem onstrated. By the dissipation mode we mean the dynamic mode in which the cantilever oscillates at a reso nance frequency and the oscillation amplitude serves as a signal of the feedback tracing a distance to the sur face. The possibility of obtaining molecular resolution when scanning in air is shown. The procedure of choosing the optimum scanning parameters is considered.

The procedure integrating independent amplitude-distance and amplitude-frequency measurements into a single routine with two variables (frequency and distance) has been developed. The domains of attraction and repulsion regimes of probe-surface interactions are clearly identified on two-dimensional patterns in frequency-distance space due to the stepwise change in a slope of constant amplitude lines and their shear on boundaries. Pattern evolution with the driving amplitude variation was studied, and three characteristic pattern types were selected. The topology of patterns obtained at intermediate drivings indicates that the probe-surface interaction is attractive at large and low cantilever-surface separations being repulsive at intermediate separations.

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Possible registration schemes of scanning plasmon near-field microscopes (SPNMs) are considered and their signal-noise ratios are evaluated. A comparison among these schemes is made with particular attention to the best scheme for a single molecule detection by a SPNM.