The hydration of phospholipids and its biological significance

The difference between the physical properties of water near the surface of certain materials and the same properties of solution water has been known for some time. The idea that this difference may also apply to the surfaces of biomolecules, cells, and tissues and, thus, may be involved in the structure function relationships of these biological entities has only recently been appreciated. The purpose of this review is to discuss the nature of this water-surface interaction as it relates to biology and medicine, to illustrate some of the methods by which this water is studied and, perhaps most importantly, to inspire the reader to consider how this ''bound water'' concept might be applied to his or her research. Such research would include transport across membranes, lateral movement along the cell surface, and lipid-protein interactions as well as many metabolic processes, both normal and pathological. Although the emphasis in this review is on the inter-action of water with phospholipids, it is the author's experience that bound water is rapidly being accepted as a useful concept in the study of other macromolecular processes, such as radiation damage in DNA and bioenergetic mechanisms in proteins. (C) Elsevier Science Inc.