The cell membrane, the interface between the cell and its environment, is the functional element in cellular metabolism and signaling. A great deal is found about the lipid, protein and saccharide constituents of membranes and their organization, and the physical properties are related with structures and functions.

A model has been utilized to study the physical properties of the cell membranes in which (glyco) proteins such as integrins, selectins, and lectins are involved in cellular interactions. On the other hand, direct measurements of the surface forces between lipid bilayers of phosphatidylethanolamine, phosphatidylcholoine, and galactolipids, the most common lipids in animal and plant membranes, suggest strong repulsive forces between highly hydrated head groups, which prevent membranes from coming into contact and reacting, adhering or fusing. Much could be known about the function and organization of the membrane's constituents if the physical properties of membranes could be measured with nano-meter scale lateral resolution.