on the modeling of the later stages of aggregation. A kinetic The disaggregation of biospecifically interacting particles in model of the ligand-receptor bond breakup is considered in shear flow is studied on the basis of kinetic modeling of formation Section 2. In Section 3 the breakup of multiparticle aggreand breakup of ligand-receptor bonds. The reaction rate theory gates is considered. Finally we combine both models to deis employed to improve earlier estimations of the critical force scribe our experimental data on disaggregation of latex imrequired to separate the surfaces. A chain of particles connected munoconjugates and blood platelets in Section 4. through ligand-receptor bonds responds to an external load as a contorted elastic rod. The breakup of the many-particle aggregate is attributed to the rupture of the backbone rod-like chain of parti-2. KINETIC MODEL OF LIGAND-RECEPTOR cles. The theoretical model is found to be in good agreement with BOND BREAKUP our experimental data on disaggregation of particles of latex immunoconjugates and blood platelets in shear flow. α§ 1997 Academic Following (2) we consider the two-stage ligand-receptor Press interaction, which obeys the following scheme: 36803-01090. kinetic parameters which will be defined below. In what 2 Current address: Kyoto Research Park, Tsukita ''Cell Axis'' ERATO follows we assume [L] 0 ΣΆ [R] 0 and set ligand and receptor