Studies Of Resonance Light Scattering Dual Wavelength Ratiometry And Its Applications In Analysis And Characterization Of Biomedical And Pharmaceutical Macromolecule And Molecular Clusters

In 1993, Pasternack et al. proposed resonance light scattering (RLS) technique originally and applied to the characterization of supermolecular assemblies. Then, Huang et al. applied that technique firstly to establish a sensitive and novel assay of nucleic acids in 1996. After that, RLS technique attracted attention due to its simple manipulation, high sensitivity and convenient experimental conditions. In this decade, RLS technique has been extensively and successfully utilized in various fields. Nowadays, RLS technique has become a powerful and routine assay in analytical chemistry.Based on the experiments of bulk solution, we bring forward a RLS ratiometric method as fellows:The followings are the main points of the first part:Studies leading to the binding of Janus Green B (JGB) with Xanthan were presented here. When pH was kept at 9.62, static interaction of JGB with Xanthan occurs and results in greatly enhanced resonance light scattering (RLS) signals characterized by a peak at 328.5 run. Linear relationships were achieved between the enhanced RLS intensity (△Irls) at 328.5 nm and Xanthan concentration in the range of 0.1-1.5 μg ml-1 if 2.2 × 10-5mol L-1 JGB was employed. The 3 σ limit of detection was 12.24ng/ml. Three synthetic samples were analyzed satisfactorily.The second part deals with the dual wavelength-rationmetric RLS method and its application in the investigating the aggregation of cationic dyes on heparin. The following is the abstract:(1) A wavelength-dependent RLS ratiometric and an absorbance ratiometric method are presented to detect biopolymer medicines based on their bindings with dyes using the interaction of heparin and JGB as an example. In aqueous solution,heparin can interact with JGB and display significantly enhanced RLS signals in uv-vis region. By measuring the RLS intensity ratio (Iratio) and absorbance ratio (Aratio) at the two wavelengths of 285.0 nm and 345.0 nm, respectively, a long dynamic range of heparin content could be detected. When JGB concentration was kept at 1.00 × 10-5 mol L-1, the detected heparin content covers in the range of 0.30 - 2000 ng ml-1 using Rratio with a limit of determination of 0.03 ng ml-1, and in the range of 0.01 - 2000.0 ng ml-1 using Aratio with a limit of determination 0.001 ng ml-1. The wavelength-dependent RLS and absorption ratiometric methods are found to have better flexibility of a series of common influences, such as pH and dye concentration than that of RLS method. Nature of the interaction was investigated through size measurements and RLS image techniques.(2) Studies leading to the wavelength-dependent RLS intensity ratiometric method are presented based on a series of interactions of heparin with some basic phenothiazine dyes. Investigate the relationship between ratio values of RLS intensities at two selected wavelengths and analyte concentration, namely, heparin content herein, this dual-wavelength RLS intensity ratiometric method is found to be with advantages of sensitivity and flexibility that enable microanalysis, in addition, discrimination of configuration differences among molecules of dyes. In slightly basified medium, phenothiazine dyes such as methylene blue (MB), Azure B (AB) and Azure A (AA) can be bound on the surface of heparin by virtue of positive-negative electronic attractions. For that, interacted systems for these four connate dyes can provide enhanced RLS signals, especially for MB. But they show vary binding ability to heparin under the optimum conditions owing to a difference of methyl location among their molecules, except for the non-response LVA. The binding nature of heparin with MB is observed using a ratio function of I366nm/I291nm and I489nm/I288nm for AB, I396nm/I284nm for AA, and the resultant dynamic ranges of heparin content for these three systems cover from 0.600 ng ml-1 to 1.20 μg ml-1, 6.00 ng ml-1 to 1.40μg ml-1, and 30.0 ng ml-1 to 1.20 μg ml-1 with limits of determination of 0.0600 ng ml-1, 0.6 ng ml-1, 3.0 ng ml-1 in turns. A method of quantitative chemistry AM 1 was adopted to calculate the electron distributions of dyes. Photon correlation spectroscopy (PCS) and RLS imaging technique show that...