Development of 3D manipulation of viscoelastic biological cells by AFM based on contact models and oscillatory drag

Since in the approximation made by the modeling and simulation of the manipulation, the accuracy plays an important role so it makes researchers to eliminate simplifications and limitations. Damping properties of the biological particles and consequently loading history of them is one of those simplifications considered until now. The other simplifying assumption is the ignorance of the oscillatory drag during modeling of the manipulation in a liquid environment elimination of which results in more precise modeling. To achieve this goal and increase the accuracy of the modeling in this paper, particles are considered viscoelastic and the oscillatory drag is added to the Stokes drag. To do so, several viscoelastic contact models are developed to choose the better suited model for biological particles. On the other hand, to modify the prediction of the particle and tool's behavior, ignored rotation about z axis is also considered. Obtained results show that considering particles viscoelastic leads to the decrease of the critical force in comparison with the elastic state. This is due to the decreasing of the deformation acceleration based on the particle's damping. These differences are about 29% for sliding of the tip on the particle, 8% for sliding of the particle on the substrate and 22% for rolling. Besides, application of the oscillatory drag force about 1.7nN leads to increasing of the drag which can be ignored in the modeling but in the case of high precision modeling this drag can be take into consideration. Therefore, it can be said that considering viscoelastic properties of the particle increases the accuracy of the modeling and simulation and as a result behavior prediction of the particles under manipulation.

Automated summary

In modeling and simulating manipulation, accuracy is crucial, leading researchers to eliminate simplifications and limitations such as damping properties of biological particles and ignorance of oscillatory drag. By considering particles viscoelastic and implementing oscillatory drag, the modeling accuracy is increased, impacting particle behavior prediction under manipulation.