Development Of Backward Resonance Light Scattering Techniques And Their Applications In Biochemical Analysis

Since resonance light scattering (RLS) technique is developed, for its remarkable characteristics of simple operation and high sensitivity, this technique has been extensively applied in the investigations of molecular aggregation behavior and the analyses of biological supermolecular and Pharmaceuticals and so on. In this contribution, based on the common RLS method, we established a new backward resonance light scattering (BRLS) technique. A highly sensitive and selective assay method of biological macromolecules is proposed based on the measurements of BRLS signals at water/tetrachloromethane (H2O/CCl4) interface.At pH 3.50, the static interaction of Naphthochrome Green (NG) with proteins occurs and results in greatly enhanced resonance light scattering (RLS) signals characterized by a peak at 277.0nm and 342.0nm. It was found that the enhanced RLS intensity (IRLS) at 342.0 nm is proportional to the concentration of proteins, and a new method for trace proteins was established accordingly. The results of determinations for urine samples were in agreement with the desired values.At pH 3.00, the interaction of aluminum (III) with the phosphate group of DNAs in aqueous solution can result in enhanced resonance light scattering (RLS) signals. The binary complex of Al(III)-DNAs then interacts with tetraphenylporphyrin (TPP) in tetrachloromethane, forming a ternary complex of TPP-Al(III)-DNAs. It was observed that greatly enhanced backward resonance light scattering (BRLS) signals occurs with maximum peak at 469 nm when the ternary complex of TPP-Al(III)-DNAs were absorbed to the liquid/liquid interface. It was found that the enhanced backward resonance light scattering intensity (Ibrls) is in proportion to the concentration of calf thymus DNA (ctDNA) and fish sperm DNA (fsDNA). The limits of detection (3a) are in thepicogram level.At pH 2.90 and ionic strength 0.003M, in the presence of cationic surfactant, we study the interaction of proteins with quercetin (QT). The resulted species of the interaction, when concentrated at H2O/CCl4 interface, generate enhanced BRLS signals characterized at 376.0 nm which were found to be proportional to human serum albumin (HSA) and bovine serum albumin (BSA) in the range of 0.8-1250 ng/mL and 1.8-1250 ng/mL, respectively. Limit of determination (3d) of 74.6 and 184 pg/mL are available for the two proteins.At pH 6.80, in the presence of TOPO, the interaction of hydrolyzed Cr(III) with the calf thymus DNA, heparin, xanthan gum in aqueous solution can result in enhanced backward resonance light scattering (BRLS) signals. When the ternary complex were absorbed to the liquid/liquid interface, it was observed that greatly enhanced BRLS signals occurs with maximum peak at 378 nm. We found that the enhanced /brls is in proportion to the concentration of biological macromolecules. The limits of determination (3d) are 0.85 ng ml-1, 1.65 ng ml-1, and 2.90 ng ml'1 for ctDNA, heparin sodium, and xanthan gum, correspondingly. We established new assay method and develop new RLS probe.