Monodomain samples of dipalmitoyl phosphatidylcholine with varying concentrations of water and other ingredients

Abstract

Methods are presented for the preparation of large monodomain phospholipid bilayer arrays containing variable amounts of water approaching the two-phase limit. The optical birefringence of these lamellar phases of dipalmitoyl phosphatidylcholine (DDPC) is measured over a range of temperature and water content, and phase transitions are observed. The techniques employed for pure DPPC and water are extended in order to produce macroscopically aligned samples containing varying concentrations of cholesterol, inorganic salts, antibiotics, and chlorophyll a. Polarization studies of the 670-nm band of chlorophyll a indicate macroscopic orientational order in the chromophore under the same conditions.