Associative Behavior Chiral Biocompatible Surfactant And Its Interaction With Levofloxacin

Chiral biocompatible surfactant could be formed to rich aggregate forms in the aqueous solutions, which not only broadened its application prospect in the biological medicine, but also gave full play to its unique effect in the application of surfactant. In this paper, based on the surfactant selectivity of hydrophilic groups and lipophilic groups, cytosine was the fixed hydrophilic group while the lipophilic group was the long-chain alkane. Three surfactants of different chain length were designed and synthesized by changing the chain length,4-Amino-l-butyl-lH-pyrimidin-2-one (C4cyt),4-Amino-l-octyl-lH-pyrimidin-2-one (C8cyt), and4-Amino-1-dodecyl-1H-pyrimidin-2-one (C12cyt). The associating behavior in aqueous solutions, and the interaction with different types of chiral substances were studied, which not only expounded the interaction of the surfactant and chiral substance from the molecular level, but also provided effective basis for separation of chiral molecules.1. Synthesis and surface properties of chiral biocompatible surfactantThree surfactants with different chain length were designed and synthesized using the substitution method,4-Amino-l-butyl-1H-pyrimidin-2-one (C4cyt),4-Amino-l-octyl-lH-pyrimi-din-2-one (C8cyt), and4-Amino-1-dodecyl-1H-pyrimidin-2-one (C12cyt). The structure of the products were characterized by IR and1H NMR, the purity was measured by elemental analyzer and differential scanning calorimeter, and the associating behavior of C4cyt in aqueous solutions was researched by the surface tension meter, conductivity meter, fluorescence spectrometer and so on. The results showed that the biocompatible surfactant obtained by using indirect synthesis method was just what we demand, and the purity is preferably satisfies the requirements of the experiment. We can see the emergence of two turning points from the curve of the surface tension and the conductivity curve, corresponding to the critical aggregation concentration (cac) and the critical micelle concentration (cmc) respectively are3.8mm and22mm. Due to the relatively low solubility in water, the association behavior of C8cyt and C12cyt in aqueous solution was not researched..2. Association behavior of chiral biocompatible surfactant Using dynamic light scattering, the surface tension to research the aggregation behavior in aqueous solution of1-butyl-1,2-dihydro-pyrimidin-4-yl-ammonium chloride ([C4cyt]Cl),1-octyl-1,2-dihydro-pyrimidin-4-yl-ammonium chloride ([C8cyt]Cl) and1-dodecyl-1,2-dihydro-pyrimi-din-4-yl-ammonium chloride ([C12cyt]Cl). Using isothermal titration calorimetry to study the thermodynamic behavior. Negative staining TEM to study its morphology. At the same time, the environment temperature on association behavior of surfactant in aqueous solution was studied. The results show that, surfactant in aqueous solution can form aggregates of different morphologies. It can be seen that, aggregates with different morphology can be formed in aqueous solution. when the concentration reaches a low level, large and loss aggregates can be formed due to hydrogen-bond interaction. While when the concentration reaches a certain range, large aggregates would be transformed to small and compact aggregates through cavities dehydration. The ambient temperature had certain effect on the aggregation behavior. The higher the temperature, the smaller the structure size, therefore we need to consider the impact of these external factors in practical application. In addition, the use of UV spectroscopy, NMR spectra announced the associative principle of surfactant. The driving force is hydrogen bonding and hydrophobic interaction.3. Interactions between the chiral biocompatible surfactants and the levofloxacinThe interactions between the three surfactant and levofloxacin were investigated using by isothermal titration calorimetry, fluorescence spectroscopy, UV-visible spectroscopy and cyclic voltammetry. Research surface:With the increasing of the surfactant’s concentration, the UV sensitizing effect was enhanced, however fluorescence quenching effect was more obvious. The reduction current of levofloxacin in the wave carbon electrode is more and more obvious with the scanning rate increasing. And the surfactant play the role of electro-catalytic. All these not only reveals the interaction mechanism, but also provide the reliable evidence for the interaction of levofloxacin in the nucleus and the bases of DNA. At last, it also provides a theoretical basis for further understanding the function of levofloxacin.