Many biotech companies are still using magnetic separation, in this process the target cell is captured by a magnetic particle, and a magnetic force pulls the target particles to one side. The amount of force generated depends on the proximity to a rare earth magnet. The non-target cells are removed while the target cells are left behind. A new buffer is added to suspend the magnetic particles.
Unfortunately, magnetic separation is expensive because of the required reagents and equipment. It’s limited to small volumes because the sample must be in close proximity to the magnetic source. The magnetic field has harsh forces that can damage delicate cells. Lastly, the throughput is limited due to the system complexity.