Double-stranded DNA liquid-crystalline dispersions as biosensing units

Three different approaches to constructing biosensing units based on double -stranded (ds) DNA molecules, capable of detecting various biologically act ive compounds, are considered. The first approach is based on the abnormal optical activity of the liquid-crystalline dispersion formed from ds DNA mo lecules, modified by relevant physical factors or treated with biologically active compounds. The second one is based on the abnormal optical activity of the liquid-crystalline dispersions formed first from the ds DNA and the n treated with coloured biologically active compounds. The third one is bas ed on the abnormal optical activity, specific to particles of the liquid-cr ystalline dispersions, where the neighbouring DNA molecules are crosslinked by artifical polymeric bridges. These approaches permit the detection of b iologically relevant compounds of various origins.