A model for describing the thermodynamics of multivalent host-guest interactions at interfaces

A model has been described for interpreting the binding of multivalent molecules to interface-immobilized monovalent receptors through multiple, independent interactions. It is based on the concept of effective concentration, C-eff, which has been developed before for multivalent binding in solution and which incorporates effects of lengths and flexibilities of linkers between interacting sites. The model assumes: (i) the interactions are independent, (ii) the maximum number of interactions, p(max), is known, (iii) C-eff is estimated from (simple) molecular models. Simulations of the thermodynamics and kinetics of multivalent host-guest binding to interfaces have been discussed, and competition with a monovalent competitor in solution has been incorporated as well. The model was successfully used to describe the binding of a divalent guest to self-assembled monolayers of a cyclodextrin host. The adsorption data of more complex guest-functionalized dendrimers, for which p(max) was not known beforehand, was interpreted as well. Finally, it has been shown that the model can aid to deconvolute contributions of multivalency and cooperativity to stability enhancements observed for the adsorption of multivalent molecules to interfaces.