Study On The Analytical Application Of Polypiridine Rutherum Nucleic Acid Molecular "Light Switch"

Fluorescence analysis is one of the widest methods in DNA study. But spectroscopic probe is need to analysis the structure or quantity of DNA for weekly luminescent itself. One of the attractive probes is a kind of polypyridine ruthenium complexes which act as nuclear acids molecular"light-switch". They have no fluorescence in water solution, but have much strong fluorescence in the presence of double helix DNA. In this paper, one of the"light-switch"complex Ru(phen)₂dppx²⁺ was applied as a spectroscopic probe to study the application of these complexes by flourescence and Rayleigh resonance light scattering methods. The main contents of this study could be described as follows:1. The interaction between daunomycin and ctDNA was studied using Ru(phen)₂dppx²⁺ as an interacting mode spectroscopic probe. And the way for Ru(phen)₂dppx²⁺ action on DNA is intercalation. The study of the influence of DNM on the ultraviolet spectra and fluorescence spectra of Ru(phen)₂dppx²⁺-DNA system indicate that DNM intercalates the base pairs of DNA. And the results of the influence of DNM on the Scatchard equation of Ru(phen)₂dppx²⁺-DNA system also indicate that DNM intercalates the base pairs of DNA.Compared with normal DNA interacting mode spectroscopic probe Ethidium Bromide (EB), Ru(phen)₂dppx²⁺ has the advantages of higher sensitivity, lower toxicity, higher stability and simplicity.2. In water solution, positive Ru(phen)₂dppx²⁺ could assemble on the surface of negative Sodium dodecylbenzene sulfonate (SDBS) and resulting in strong resonance rayleigh scattering. Because the strong affinity between Ru(phen)₂dppx²⁺ and DNA (KB≥106 L/mol), Ru(phen)₂dppx²⁺ will separated with SDBS while DNA was added, and resulting scattering light reduce greatly. The decrease of resonance Rayleigh scattering light is linear to the concentration of DNA. Based on which, a novel method is proposed for the determination of DNA.