File:Fluctuating-Nonlinear-Spring-Model-of-Mechanical-Deformation-of-Biological-Particles-pcbi.1004729.s011.ogv

English: Dynamic force spectroscopy in silico : Forced indentation of CCMV capsid along the 2-fold symmetry axis. The movie shows the forced indentation experiment in silico on the CCMV shell, in which a compressive force is applied along the 2-fold symmetry axis (side view). The CCMV capsid is positioned on a solid mica surface (small gray colored beads). The cantilever base is moving with the velocity νf = 1.0 μm/s perpendicular to the surface of the CCMV shell. As a result, the cantilever tip (large gray colored sphere of radius Rtip = 20 nm) exerts pressure onto the outer surface of the CCMV shell, which undergoes a series of transformations: Heartzian deformation at the early stage of indentation is followed by the bending deformation of the shell side portions, leading to the structural collapse of the capsid. The beams forming the “capsid barrel” fail but not all the same time, which demonstrates the stochastic nature of collapse transitions in vertical beams. Also, formation of small cracks gradually developing into structural damage is clearly observed. The movie stops when the indentation depth X reaches X = 20 nm. The duration of the indentation experiment is ∼40 ms and the length of the movie is ∼33 s (the movie is played ∼825 times slower than the experiment).