Probing self assembly in biological mixed colloids by SANS, deuteration and molecular manipulation

Conference · Sat Dec 31 04:00:00 EST 1994

DOI:https://doi.org/10.1007/978-1-4615-5847-7_16· OSTI ID:381082

Hjelm, R P ^[1]; Thiyagarajan, P ^[2]; Hoffman, A ^[3]; Alkan-Onyuksel, H ^[4]

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1. Los Alamos National Laboratory, NM (United States)
2. Argonne National Laboratory, IL (United States)
3. Univ. of California, San Diego, CA (United States)
4. Univ. of Illinois, Chicago, IL (United States)

Small-angle neutron scattering was used to obtain information on the form and molecular arrangement of particles in mixed colloids of bile salts with phosphatidylcholine, and bile salts with monoolein. Both types of systems showed the same general characteristics. The particle form was highly dependent on total lipid concentration. At the highest concentrations the particles were globular mixed micelles with an overall size of 50{Angstrom}. As the concentration was reduced the mixed micelles elongated, becoming rodlike with diameter about 50{Angstrom}. The rods had a radial core-shell structure in which the phosphatidylcholine or monoolein fatty tails were arranged radially to form the core with the headgroups pointing outward to form the shell. The bile salts were at the interface between the shell and core with the hydrophilic parts facing outward as part of the shell. The lengths of the rods increased and became more polydispersed with dilution. At sufficiently low concentrations the mixed micelles transformed into single bilayer vesicles. These results give insight on the physiological function of bile and on the rules governing the self assembly of bile particles in the hepatic duct and the small intestine.

• Research Organization: Los Alamos National Lab., NM (United States)
• OSTI ID: 381082
• Report Number(s): LA-UR--96-634; CONF-9410223--; ON: DE96006681
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
66 PHYSICS
99 GENERAL AND MISCELLANEOUS
BILE
BIOCHEMISTRY
CALCULATION METHODS
COLLOIDS
DEUTERATION
LECITHINS
MOLECULAR STRUCTURE
NEUTRON DIFFRACTION
SALTS
SMALL ANGLE SCATTERING
STRUCTURAL MODELS