Cell mortality associated with acute hydrodynamic stressors from capillary pinch-off

From bubbles bursting in bioreactors to droplets flung off rupturing fluid films, rapidly rearranging fluid interfaces have the potential to generate immense hydrodynamic stressors in the nearby fluid. Biological cells near these interfaces—e.g. bacteria in respiratory droplets—must navigate this stressful environment in order to survive. Past studies have shown that elevated hydrodynamic stressors over longer periods of time can negatively impact cell viability. However, the impact that short timescale hydrodynamic stressors have on cell viability is not well understood. Here we quantify, using numerical simulations, spatiotemporal hydrodynamic stressors for a range of biologically inspired fluid flows. We also experimentally measure the viability of mammalian cells near to bubbles undergoing a short timescale rearrangement. Our results show that short timescale hydrodynamic stressors can predictably lower the viability of biological cells. Furthermore, the above result combined with the stressors from simulations, suggest a hydrodynamical selectivity on the droplet-based transport of certain microorganisms. We anticipate our study to catalyze more refined modelling of the relationship between stressor magnitude and duration, and microorganism viability and proliferation.