Light Scattering Characteristics On The Interactions Of Biological Dyes With Biomacromolecules In Vitro And Their Analytical Applications

Biological dyes, widely exist in nature and organisms, and participate in manyimportant biophysical processes such as photosynthesis and transportation of zoeticsubstances, so it is of important significance to investigate the interactions of biological dyes with biomacromolecules in vitro. In this thesis, biological dyes with the ability of resistant to bacteria are selected as hosts of molecular recognition, and the mechanisms of the interactions of them with biomacromecules are investigated by resonance light scattering (RLS) technique and photoelectron absorption spectra, Based on the enhanced RLS signals of the interactions, rapid and sensitive assays of nucleic acids and proteins are established.Azur A (AA), Azur B (AB) and Janus green B belong to quaternanry ammonium salt biological dyes. In proper acidity and ionic strength, significantly enhanced RLS signals are obtained when they interact with a trace amount of nucleic acids and the enhanced RLS intensity is in good proportion to the concentration of nucleic acids. Based on this, determinations of nucleic acids with limit of detection (LOD) below 10.0 ng/ml are proposed and corresponding mechanisms are also discussed primarily.In neutral aqueous solution, the interaction of ABGX with DNA results in strong enhanced RLS signals characterized by three peaks at 398.8 nm, 451.1 nm and 469.0 nm. Electrostatic attraction mechanism of ABGX with DNA was established based on the measurements of RLS and absorption data. Under the optimum conditions, assay of DNA at nanogram levels are also established by detecting theenhanced RLS signals at 398.8 nm in the rang of 0-2.0 ug/ml for both ctDNA and fsDNA.Fuchsine acids and Fast Green FCF are anionic triarylmethane biological dyes. In acidic medium, their RLS intensities are greatly enhanced by proteins with the RLS characterized peaks at 277.0 nm and 279.0 nm, respectively. It was found that the enhanced RLS intensities were in proportion to the concentrations of proteins in a certain range. Fast green FCF used as the probe of proteins is the most sensitive method of proteins in RLS technique and its limit of detection (LOD) is 0.6 ng/ml. The results of determination of proteins in human urine samples with Fuchsine acidand Fast green by use of RLS technique are satisfactory.In neutral solution, the interaction of Alcian blue 8GX (ABGX) and proteins cangive rise to significantly enhanced RLS signals. According to the enhanced intensities at 398.0 nm, proteins of the concentration range of 0-3.5 u.g/ml can be detected when employing different concentrations of ABGX and its limit of detection (LOD) is less than 30.0 ng/ml. The artificial samples can be determined with good reproducibility. The results of determination for proteins in human blood serum are identical with those obtained according to CBB G-250 Bradford method.