Biofilm formation is a complex phenomenon involving biopolymers and microorganisms. The first step is the formation of a conditioning film by non-specific adsorption of non-microbial components that microbes will later on colonize. Two main components of the conditioning film are proteins and carbohydrates. Here the adsorption of important salivary proteins (bovine serum albumin (BSA), lysozyme (LYZ)) and a polysaccharide (dextran) on dental titanium was investigated by a multimethod approach of biochemical assays (to determine protein and carbohydrate amounts and lysozyme activity) and surface analytical methods (scanning force microscopy and quartz crystal microbalance). Main emphasis in this study was put on the interplay of the two proteins and between the proteins and the polysaccharide.
Exposition of titanium surfaces to solutions containing BSA and LYZ simultaneously leads to a larger amount of adsorbed proteins compared to the adsorption of pure protein solutions of either BSA or LYZ. This cooperative effect could be attributed to BSA−-LYZ+-agglomerates formed in bulk solution. Further, LYZ activity is increased in the presence of BSA by 70 % for 1:1 molar ratio.
First results for simultaneous and consecutive exposition of titanium surfaces to BSA and dextran solutions give a hint that also here cooperative and in addition, displacement effects take place.