On cell surfaces the adhesive interactions are mediated by a
complex interplay of surfaces forces, mainly hydrogen bonding,
dispersion forces, hydrophobic interactions and electrostatic interactions
[3]. Although the number of possible binding partners is
very large there has been considerable success in the identification
of specific ligand/receptor pairs involved in adhesive interaction of
cells. Deciphering the various types of protein receptors involved in
cellesurface interaction is typically done by a series of cell assays
that analyze cell response to added ligands. However, such assays
measure the ligand/receptor interaction indirectly, e.g. by quantifying
certain marker molecules, morphological changes of the cell
or subsequent intracellular responses. On the other hand, a direct
measurement of the adhesive interaction of ligand/receptor pairs
may give information on the nature of the interaction, such as
discrimination between specific and unspecific binding or the role
of various physical cues like external force, rate constants or contact
time [4,5].