Technical Papers and Presentations

The yeast Saccharomyces cerevisiae has been used for the study of aging in eukaryotic cells. The traditional method for this study uses micromanipulators which makes it difficult, time consuming and expensive. Over time, different microfluidic platforms, usually referred to as 'mother machines', have emerged to make this process easier. However, these methods use mechanical trapping, which puts pressure on the cell, which can affect its physiology (growth rate, genetic expression, aging, etc.). To avoid this, we designed a new microfluidic platform that does not use mechanical but hydrodynamical trapping, with the objective of trapping the mother cell so that the daughter cells can be separated. Using COMSOL Multiphysics® software, we designed and simulated a geometry to analyze different parameters in the trapping of the mother cell in the mother machine. The device consists of a channel consisting of an inlet, an outlet, and within it a total of 255 traps (Figure 1). We defined the input value (speed = 1.17m / s) from the flow (3.6 ml/h) and the channel geometry and the output value (pressure = 0 Pa), using the Navier-stokes equation by the finite element method. After this the real experiment was carried out which had a duration of 48 hours. It was observed that where there was greater cell retention, that is a higher trapping rate, was in the traps found on the borders of the channel, but this happens only at the beginning of the channel, because when observing the (Figure 1) after column 8 the velocity flow becomes more homogeneous, that means that in all the channel there is a higher retention.

The convergence of the solutions was tested by evaluating the speed changes in the separation of each column, taking into account the mesh scale (normal). After knowing the behavior of the speed in the entire channel, it was found for each individual trap, only in the first column, in order to know the pressure profile, obtaining that where the mother cell is trapped is where the flow is very weak, causing the pressure gradient to generate a negative force (opposite to the flow). The daughter cells detach due to a positive force (in the same direction of the flow). Finally, from the results we can see that the pressure profile for each trap allows the mother cell to be trapped and the daughter cell to be separated. These results can be verified with data from the real experiment, where the same behavior of the simulation is observed.