By making use of the fluorescence quenching properties of safranine T(ST) in its long range assembly on the molecular surfaces of nucleic acids, the assembly number and constant of ST with calf thymus DNA, fish sperm ...By making use of the fluorescence quenching properties of safranine T(ST) in its long range assembly on the molecular surfaces of nucleic acids, the assembly number and constant of ST with calf thymus DNA, fish sperm DNA and yeast RNA were determined at 12℃. The corresponding free energy change, enthalpy change and entropy change of the long range assembly were calculated at the same temperature. It was found the assembly complexes are very stable and the assembly is a spontaneous process characterized an entropy increase.展开更多
The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2?] self-assem...The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2?] self-assembles on the surface of positively-charged gold nanopar-ticle, which results in the [(Au)n(H2L)m]x? complex. In other words, one of carboxylate oxygens in (H2L)2? moves inward and combines with gold nanoparticle. The other carboxylate oxygens moves outward to form a supermolecular complex anion with x negative charges. Then by virtue of electrostatic attraction, hydrophobic force and charge transfer action, the complex anion binds with ST cation to form a new ion-association complex. Here (H2L)2? acts as a bridge. The forma-tion of the complex results in the significant enhancement of RRS intensity, the appearance of new RRS spectrum, the red shift of plasma absorption band of gold nanoparticle as well as the decrease in the absorbance and fluorescence quenching for safranine T. In this work, the inter-action between gold nanoparticle and ST on the RRS, absorption and fluorescence spectra has been investigated. The reason why RRS intensity increases greatly and the reaction mechanism have been inquired. The results show that RRS spectra can not only be used to study nanopar-ticle and reaction product, but also are a sensitive means to characterize and detect nanoparti-cles.展开更多
A study of the electrochemical reduction behavior of safranine T by means of electrochemical methods coupled with ESR （electron spin resonance） is presented. Through an "in situ" tracing of the 1-electron ...A study of the electrochemical reduction behavior of safranine T by means of electrochemical methods coupled with ESR （electron spin resonance） is presented. Through an "in situ" tracing of the 1-electron reduction intermediate—free radical, the structure of the free radical has been deduced. During the electrochemical reduction the free radical went through a post-electrolysis chemical decay including parallel steps of zero and first order reactions. This fact gives further support and experimental ascertainment of the viewpoint that some electrode processes are clearly related to the enzymatic catalyses<sup>[1]</sup>. In accordance with the chemical behavior of safranine T free radicals at various concentrations and at different potentials the authors have advanced a scheme of reaction mechanism and evaluated the kinetic parameters of the reation steps by simulating the experimental curves.展开更多
The interaction between safranine T(ST) and yeast DNA was studied by means of UV absorption and fluorescence spectrometry. The wavelengths of fluorescence excitation and emission of ST were 520 nm and 570 nm, respecti...The interaction between safranine T(ST) and yeast DNA was studied by means of UV absorption and fluorescence spectrometry. The wavelengths of fluorescence excitation and emission of ST were 520 nm and 570 nm, respectively. The maximum absorption of UV spectrum was at 520 nm. Two kinds of interaction between ST and DNA, intercalation and electrostatic interaction, were conformed. The binding site size in DNA base pairs was 14.5±1.5 and the apparent binding constant was (2.81±0.11)×10 4 mol -1·L. The fluorescence quenching constant of DNA to ST was (1.52±0.19)×10 4 mol -1·L. A novel fluorescence analysis for DNA determination was presented and the effects of experimental conditions on the fluorescence quenching were discussed.展开更多
文摘By making use of the fluorescence quenching properties of safranine T(ST) in its long range assembly on the molecular surfaces of nucleic acids, the assembly number and constant of ST with calf thymus DNA, fish sperm DNA and yeast RNA were determined at 12℃. The corresponding free energy change, enthalpy change and entropy change of the long range assembly were calculated at the same temperature. It was found the assembly complexes are very stable and the assembly is a spontaneous process characterized an entropy increase.
基金the National Natural Science Foundation of China(Grant No.20175018).
文摘The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2?] self-assembles on the surface of positively-charged gold nanopar-ticle, which results in the [(Au)n(H2L)m]x? complex. In other words, one of carboxylate oxygens in (H2L)2? moves inward and combines with gold nanoparticle. The other carboxylate oxygens moves outward to form a supermolecular complex anion with x negative charges. Then by virtue of electrostatic attraction, hydrophobic force and charge transfer action, the complex anion binds with ST cation to form a new ion-association complex. Here (H2L)2? acts as a bridge. The forma-tion of the complex results in the significant enhancement of RRS intensity, the appearance of new RRS spectrum, the red shift of plasma absorption band of gold nanoparticle as well as the decrease in the absorbance and fluorescence quenching for safranine T. In this work, the inter-action between gold nanoparticle and ST on the RRS, absorption and fluorescence spectra has been investigated. The reason why RRS intensity increases greatly and the reaction mechanism have been inquired. The results show that RRS spectra can not only be used to study nanopar-ticle and reaction product, but also are a sensitive means to characterize and detect nanoparti-cles.
基金Project supported by the National Natural Science Foundation of China.
文摘A study of the electrochemical reduction behavior of safranine T by means of electrochemical methods coupled with ESR （electron spin resonance） is presented. Through an "in situ" tracing of the 1-electron reduction intermediate—free radical, the structure of the free radical has been deduced. During the electrochemical reduction the free radical went through a post-electrolysis chemical decay including parallel steps of zero and first order reactions. This fact gives further support and experimental ascertainment of the viewpoint that some electrode processes are clearly related to the enzymatic catalyses<sup>[1]</sup>. In accordance with the chemical behavior of safranine T free radicals at various concentrations and at different potentials the authors have advanced a scheme of reaction mechanism and evaluated the kinetic parameters of the reation steps by simulating the experimental curves.
文摘The interaction between safranine T(ST) and yeast DNA was studied by means of UV absorption and fluorescence spectrometry. The wavelengths of fluorescence excitation and emission of ST were 520 nm and 570 nm, respectively. The maximum absorption of UV spectrum was at 520 nm. Two kinds of interaction between ST and DNA, intercalation and electrostatic interaction, were conformed. The binding site size in DNA base pairs was 14.5±1.5 and the apparent binding constant was (2.81±0.11)×10 4 mol -1·L. The fluorescence quenching constant of DNA to ST was (1.52±0.19)×10 4 mol -1·L. A novel fluorescence analysis for DNA determination was presented and the effects of experimental conditions on the fluorescence quenching were discussed.
