The difference between the physical properties of water near the surfa
ce 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 revie
w is to discuss the nature of this water-surface interaction as it rel
ates to biology and medicine, to illustrate some of the methods by whi
ch 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 m
embranes, lateral movement along the cell surface, and lipid-protein i
nteractions as well as many metabolic processes, both normal and patho
logical. Although the emphasis in this review is on the inter-action o
f water with phospholipids, it is the author's experience that bound w
ater is rapidly being accepted as a useful concept in the study of oth
er macromolecular processes, such as radiation damage in DNA and bioen
ergetic mechanisms in proteins. (C) Elsevier Science Inc.