| Abstract
| - In a previous work, conditions for which a ligand reversibly bound to a planar surface dissociates and thenrebinds to the surface were theoretically examined (Lagerholm, B. C.; Thompson, N. L. Biophys. J. 1998, 74,1215). The coupled differential equations that describe the reversible interaction of ligands in three-dimensionalsolution with sites on a planar surface were solved to find analytical solutions for the probabilities of findinga ligand on the surface or in solution, given initial placement on the surface. An expression was also foundfor the probability that a ligand rebinds to the surface at a given position and time after its release. In thiswork, the formalism is extended to calculate analytical, closed form expressions for the average number andrate of rebinding events that have occurred, on the average, at a given time after placing a ligand on thesurface. These functions depend only on the intrinsic dissociation rate and a “rebinding parameter,” whichdepends on a group of constants including the intrinsic association and dissociation rates, the density ofsurface binding sites, and the diffusion coefficient in solution. The results are interpreted in terms of typicalconditions for biologically relevant ligands and their receptors.
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