Lipid membrane surface and interfacial water

The lipid membrane surface and its associated water molecules form a dynamic interface that is fundamental to the structure and function of biological membranes. Lipid membranes are composed primarily of amphipathic molecules—phospholipids, cholesterol, and glycolipids—that spontaneously organize into bilayers in aqueous environments, resulting in a hydrophobic core and hydrophilic surfaces[2][3]. Close to the hydrophilic membrane surfaces, water molecules form a structured "hydration shell", mediated by hydrogen bonding between water and the charged or dipolar headgroups of membrane lipids[1][4][6]. This interface influences membrane stability, facilitates biochemical reactions, and modulates the interactions of proteins and solutes with the membrane. Water molecules at the membrane surface are distinguished by reduced translational and rotational mobility compared to bulk water, forming stable water bridges with lipid headgroups that are crucial for maintaining membrane integrity and influencing functions such as signaling and molecular transport[1][5][6]. The structure and dynamics of this interfacial water layer are sensitive to lipid composition, membrane charge, ion concentration, and temperature[4][5]. Although not a direct therapeutic target, alterations in this interfacial layer can impact cell physiology and pathology. Note: This entry should not be treated as a classic drug target (receptor, enzyme, channel, etc.) but rather as a fundamental biophysical concept central to membrane biology and interfacial water phenomena[2][3][6].

Other names

Lipid bilayer–water interfacemembrane interface hydrationmembrane-associated watermembrane surface hydration layer