Model and simulation of multivalent binding to fixed ligands

A model to quantitate the principal aspects of mul-tivalent binding was developed. It describes the ran-dom distribution of an immobilized component (the ligand) taking into account local densities. The bind-ing of a bivalent molecule (the analyte) to the ligand is described as occurring in two steps, the second of which is driven by the local concentration of neigh-boring ligands. The model was used to simulate the kinetics of bivalent binding in surface plasmon reso-nance biosensors such as BIAcore. The simulations are compared with measured data. The simulation quan-titates the influence of bivalent binding on the sensor signal, as a function of ligand density, analyte concen-tration, and binding site distance. Such simulations will be helpful for understanding and designing exper