Changes in Cholesterol Surface Free Energy Components Due to Its Phase Transition

✍ Scribed by M.L. Kerkeb; F. González-Caballero; E. Chibowski

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 229 KB
• Volume: 159
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1993.1344

✦ Synopsis

Changes in cholesterol surface free energy components as a function of temperature were studied. The components were calculated from the measured contact angles of diiodomethane, tetrabromomethane, water, and glycerol in the range (20-50^{\circ} \mathrm{C}). First, changes in the liquid surface tension components were determined from the measured surface and interfacial tensions. It was found that at the temperatures of cholesterol phase transition (\left(35-40^{\circ} \mathrm{C}\right.) ) an abrupt change in its surface free energy takes place. The nonpolar, Lifshitz-van der Waals interaction increases by (4.34 \mathrm{~mJ} / \mathrm{m}^{2}), whereas the polar acid-base interaction drops down by (1.0 \mathrm{~mJ} / \mathrm{m}^{2}). However, in effect, between 35 and (40^{\circ} \mathrm{C}) the hydrophobicity of the surface increases, because the work of water adhesion decreases from 72.8 to (70.6 \mathrm{~mJ} / \mathrm{m}^{2}), respectively. This finding may be important for a better understanding of the cholesterol deposition inside the blood vessels. Q 1993 Academic Press, Inc.