Original scientific paper

Non-Equilibrium Behavior in Egg Phosphatidylcholine-Bile Salt Mixed Aqueous Colloids

Rex P. Hjelm, Jr. ; Los Alamos Neutron Scattering Center, Los Alamos National Laboratory Los Alamos, New Mexico 87545, USA
Jess Wilcoxon ; Organization 1153, Sandia National Laboratory, Albuquerque, NM USA
P. Thiyagarajan ; Intense Neutron Source and Chemistry Divisions, Argonne National Laboratory Argonne, II. 60436, USA
Hayat Alkan ; Department Pharmaceutics, University of Illinois, Chicago, II. 60680, USA

Abstract

Aqueous mixed colloids of bile salt and phosphatidylcholine have particle morphologies that are highly dependent on total lipid concentration. Starting at the highest concentrations globular mixed micelles are found. These elongate into rods with dilution, and then transform into vesicles at the lowest lipid concentrations. Little is known of the mechanism of these concentration-dependent transformations. Here, we report observations from static and dynamic light scattering on egg phosphatidylcholine-glycocholate mixtures, showing that the system passes through a series of large structures upon dilution. As the mixed colloid is diluted to concentrations close to or at the vesicle transition, a well defined structure is formed initially, which is likely to be an aggregate of mixed micelles. This structure then undergoes a series of transformations. The discovery of this structure could be an important clue in understanding the transition from rod-like to vesicle forms.

Keywords

Hrčak ID:

137180

URI

https://hrcak.srce.hr/137180

Publication date:

15.8.1992.

Visits: 638 *