Stacking structures of dry phospholipid films on a solid substrate

Stacking structures and surface morphologies of dry phospholipid films on a solid substrate were investigated by X-ray reflectivity (XR) and atomic force microscopy (AFM). A 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) film in the liquid-crystalline phase was stacked regularly and formed a terrace-like morphology, while a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) film in the gel phase showed a rough morphology with random layering. This difference in the stacking structure is discussed in relation to the ability of formation of phospholipid giant vesicles by the natural swelling method [M. Hishida, H. Seto, K. Yoshikawa, Chem. Phys. Lett. 411 (2005) 267].