Cell Sorting
Many microfluidic devices that perform cell sorting make use of the difference in physical properties of drops. This method, called inertial focusing, provides a high throughput compared to the traditional techniques of cell sorting like Fluorescent Activated Cell Sorting (FCAS) and Magnetic Activated Cell Sorting (MCAS).
Inertial Focusing
Drops moving in a microfluidic channel with Poiseuille Flow experience unbalanced lateral forces until they reach an equilibrium position along the breadth and height of the channel. The equilibrium position depends heavily on various properties like cell size and its deformability. The phenomenon is generally called Inertial Focusing of drops and is being utilized for cell sorting purposes in microfluidic sorting devices to separate cells with different physical properties particularly size and deformability.
Threshold Volume Fraction
A high throughput device is desirable but it has been observed experimentally that if the inlet solution is too dense, the device wouldn’t work properly and the cell sorting efficiency would reduce significantly, thus making the process unfeasible. It can be concluded that there must be a Threshold Volume Fraction of drops in solution, beyond which the drops stop reaching their equilibrium positions.
Many numerical studies so far focus on a single drop and how it reaches the equilibrium position, while none have focused on the interactions of multiple drops.
A numerical study is being performed to find out the threshold volume fraction and what properties of fluid influence them most. This would give us an indication of how much dilution is required to get maximum throughput out of a sorting device.
