Stabilization of the lamellar structure of phosphatidylcholine by complex formation with trehalose

Trehalose (Tre) is found at particularly high concentration in anhydrobiotic organisms, and is effective in stabilizing the bilayer membranes of phospholipids in freeze-drying. We studied the mixture of L-α-dipalmitoylphosphatidylcholine (DPPC) and trehalose at various water contents by differential scanning calorimetry (DSC) and the small angle X-ray diffraction method. The Tre intercalated between lipid bilayers and formed complexes, and the excess Tre crystallized as its dihydrate by the addition of water. The amount of the dihydrate was estimated from the peak area in DSC. The experimental values of the molar ratio (Tre/DPPC) of the complexes thus determined were 1:2 and 1:1, and the corresponding expansions of the lamellar spacing were observed by small angle X-ray diffraction.