  The control of biofilm formation is a challenging goal that has not been
reached yet in many aspects. One is the role of van der Waals forces and
another the importance of mutual interactions between the adsorbing and the
adsorbed biomolecules ('critical crowding'). Here, a combined exeperimental and
theoretical approach is presented that fundamentally probes both aspects. On
three model proteins, lysozyme, {\alpha}-amylase and bovine serum albumin
(BSA), the adsorption kinetics is studied. Composite substrates are used
enabling a separation of the short- and the long-range forces. Though usually
neglected, experimental evidence is given for the influence of van der Waals
forces on the protein adsorption as revealed by in situ ellipsometry. The three
proteins were chosen for their different conformational stability in order to
investigate the influence of conformational changes on the adsorption kinetics.
Monte Carlo simulations are used to develop a model for these experimental
results by assuming an internal degree of freedom to represent conformational
changes. The simulations also provide data on the distribution of adsorption
sites. By in situ atomic force microscopy we can also test this distribution
experimentally which opens the possibility to e.g. investigate the interactions
between adsorbed proteins.
