Modeling and simulation of three-dimensional manipulation of viscoelastic folded biological particles considering the nonlinear model of the cell by AFM

摘要

Previous research on biological particles manipulation has taken into account linear cellular models and spherical geometry, Whereas, particles such as bacteria and cancer cells have cylindrical and crushed cylindrical geometry. On the other hand, cell behavior is nonlinear. Therefore, it is important to apply above mentioned models in the manipulation models and to investigate the modes of motion in the cylindrical nanoparticle manipulation to calculate the critical time and forces in order to understand the properties and behavior of these particles. In this paper, we present the analytical nonlinear cellular mechanical models that lead to the extraction of the creep function proportional to the biological particle behavior. Cylindrical and crushed cylindrical geometry considered in manipulation simulation. The cell is modeled with 2nd and 3rd order nonlinear spring and damper which are parallel and series. At the end, 2nd order nonlinear Kelvin selected as the most appropriate model. Comparison with the cell model of power-law and experimental data led to correction coefficients in models. Hereafter, JKR viscoelastic contact model was proposed for nanoparticles with cylindrical and crushed cylindrical geometry. Then, the application of cell models in the contact model and subsequently modeling of the first phase of the manipulation, considering folding factor, has been done. By simulating the main motion modes, including the mode of the slip of the probe tip on the particle, particle's rotation on the surface and the mode of slipping the particle on the surface, the force and critical times were obtained. According to the results, for a particle with a cylindrical geometry, the slip mode of the particle on the surface happens in 505.4 milliseconds and 5 microseconds faster than other modes. Besides, applying the folding factor causes an increase of 7% in the critical time. Because the folded shape of the cell surface causes more disturbance and friction, it requires more time and force to move the particle away and is matched to the physics of the problem. For a particle with a crushed cylindrical geometry, the slip of the probe tip on the particle occurs in 420.7 milliseconds and 10 milliseconds faster than other modes and under the force of 0.7255 micro N and about 71 percent less than the others. Also, the application of the folding factor for this particle contributes to an increase of 24% in critical force and an increase of 11% in the critical time.