Study On Dynamic Specific Adhesion Behavior Of Viscoelastic Media

Adhesion through receptor-ligand molecular cluster between cell and cell or cell and substrat is known as specific adhesion, and it plays an important role in the construction of the biological organism and cell growth, migration and so on all. The study found that cell mechanics properties directly affect the cell adhesion ability. Based on the findings, predecessors builded different specific adhesion models:random-elastic coupling cell adhesion model; diffused-elastic coupling cell adhesion model. But these models didn’t involve cell intrinsicly viscoelastic properties. Do the viscoelastic properties of cell have effect on specific adhesion process? In order to answer this question and further make clear the effects of cell viscoelastic properties on the adhesion behavior, this study, which is based of cell adhesion, aimed at the dynamics behavior of the adhesion system, considered viscoelastic and elastic half-space adhesion system formed through receptor-ligand molecular cluster and established adhesion model involving coupling effect of adhesion molecular bonds random chemical reaction and viscoelastic and elastic deformation of media and substrat. Based on this model, we simulated the kinetics of cell adhesion through Monte Carlo simulation method, quantitatively analyzed the influence of cell viscousity, substrat elasticity and loading rate on specific adhesion behavior:(1) By simulating the dynamic evolution of adhesion molecular cluster, we found the rule that random damage of adhesion molecular cluster expands from adhesion area edge to the center; (2) Finding the viscosity of media can prolong the lifetime of specific adhesion, this is due to its recovery process of cell viscoelastic deformation increases the closed probability of open molecular bonds; (3) By studying the substrate elastic effects on the cell adhesion system, further verified the conclusion of the existing theoretical models that harder sbstrate elasticity can enhance the adhesion between cell and sbstrate; (4) Evolutionary process of cell-substrat adhesion under dynamic loading is given both in space and time scales; we found the loading rate had important influence on the evolution process, namely, under the fast loading rate, cell adhesion strength was stronger. This is due to competition between the loading rate and the reaction rate of specific molecular, and when the loading rate is very fast, the initial closed molecular bonds have no time to open, then they have a lot of elastic stretching, which corresponds to the larger adhesion strength. All in all, based on specific adhesion model of viscoelastic media, we further study the influence of cell viscoelastic mechanical properties on specific adhesion, this study can help people deepen to understand the cell adhesion behavior.