Regulation of the spatial organization of DNA molecules in particles of liquid-crystalline dispersions by means of biologically active compounds

Using the “structural conflict” method based on differences in the spatial organization of a liquid-crystalline dispersion (LCD) of DNA-polycation complexes and the DNA cholesteric LCD, it was shown that in a solvent with specific properties, the spatial structure of the LCD of DNA-polycation complexes can be controlled by biologically active compounds (BAC) that cause either dissociation of the DNA-polycation complex or destruction of the polycation molecules. In both cases, the cholesteric structure of LCD typical of the initial uncomplexed DNA molecules is recovered. The recovery of cholesteric LCD of DNA was proved by circular dichroism spectroscopy and confirmed by X-ray diffraction and polarization microscopy. The fact that spatial restructuring of LCD of the DNA-polycation complexes is induced by BAC in low concentrations opens up the possibility for using particles of these dispersions as sensing elements (sandwich-type biosensing units) of biosensor devices. A new method for determination of heparin based on the use of LCD of the DNA-polyconidine complexes was developed. The minimum heparin concentration determined in the sample equals ∼ 0.4–0.5 µg mL−1.