Nanoscale cavitation in perforation of cellular membrane by shock-wave induced nanobubble collapse

The collapse of the bubble induced by the shock wave leads to nano-jet, which is able to perforate cellular membranes. This phenomenon is investigated by Martini coarse-grained molecular dynamic (CG-MD) simulations in the present study. It is found that the occurrence of cavitation nucleation at the nanoscale can be observed during the perforation process. The cavitation locates near the puncture of the cell membrane and its ultimate evolutionary form presents a ring-like structure. The volume of the cavitation is calculated for different initial bubble sizes, and it is found that the maximum volume of the cavitation area has a correlation with the initial bubble size. To understand the underlying physics of the cavitation phenomenon, the classical nucleation theory based on the Rayleigh-Plesset equation is applied to the non-equilibrium nanoscale system after the pressure field is obtained by using the Irving-Kirkwood-Noll procedure. The consistence between the results of CG-MD and the theory reveals that the average pressure of the local environment plays a crucial role in cavitation occurrence on the non-equilibrium system subjected to strong inertia, e.g., shock wave and nano-jet.