Department of Chemistry, Veer Narmad South Gujarat University, Surat 395007, India.
Shah-Schulman Center for Surface Science & Nanotechnology, Dharmsinh Desai University, Nadiad 387001, India.
J Colloid Interface Sci. 2015 Mar 1;441:106-12. doi: 10.1016/j.jcis.2014.11.027. Epub 2014 Nov 18.
Aqueous solution behaviour of a nonionic surfactant Triton X-100 is investigated in the presence of two bile salts namely sodium deoxycholate (NaDC) and sodium cholate (NaC) at different pH, temperatures and in the presence of sodium chloride and the resultant structural changes to accordingly formed mixed micelles were analyzed by using cloud point (CP), viscosity and scattering techniques. Both the bile salts increased the CP and showed a corresponding decrease in viscosity and apparent hydrodynamic diameter (Dh), which can further be subsided with the progressive addition of sodium chloride and an increase in temperature. Interestingly, in the presence of bile salt below pH ∼5, CP decreased with corresponding increase in viscosity, while a reversed trend was observed above pH∼8. Small angle neutron scattering data reveal that nearly spherical mixed micelles were formed in the presence of bile salt which grow and transform to prolate ellipsoidal ones at pH∼3. These morphological changes are facilitated by the protonation of carboxylic acid group of bile salt and deeper penetration of bile acid molecules into TX-100 micelles at lower pH. Proposed molecular interactions are extremely informative to understand more about these biologically important compounds playing a crucial role in digestion processes.
非离子表面活性剂 Triton X-100 在两种胆汁盐（脱氧胆酸钠（NaDC）和胆酸钠（NaC））存在下的水溶液行为在不同 pH 值、温度下以及在氯化钠存在下进行了研究，相应形成的混合胶束的结构变化通过浊点（CP）、粘度和散射技术进行了分析。两种胆汁盐均增加了 CP，并表现出相应的粘度降低和表观流体力学直径（Dh）减小，随着氯化钠的逐步添加和温度的升高，这种情况进一步加剧。有趣的是，在 pH∼5 以下的胆汁盐存在下，CP 随粘度的增加而降低，而在 pH∼8 以上则观察到相反的趋势。小角中子散射数据表明，在胆汁盐存在下形成了近球形的混合胶束，这些胶束在 pH∼3 时生长并转化为长椭球形胶束。这些形态变化是由胆汁盐羧酸基团的质子化和胆汁酸分子在较低 pH 值下更深地渗透到 TX-100 胶束中促进的。所提出的分子相互作用对于理解这些在消化过程中起着关键作用的生物重要化合物非常有帮助。
