Sorting cells from a heterogeneous population enables the study of the different isolated types, but also allows for the introduction of enriched cell populations to a patient. The use of highly selective separation procedures is also critical to improve cell-based treatments on stem cell therapy, tissue engineering and regenerative medicine.
In a typical magnetic cell sorting process, the magnetic beads are added to a cell-sample, which is then incubated. When these labeled cells are placed with the entire mixed-cell population into a Biomagnetic Separation system, the targeted cells are pulled by magnetic force, separating them from the cell culture with the attached beads.
If you are interested in cell isolation with biomagnetic separation, download our newest guideDoes it matter which magnetic separation rack I use in my cell isolation processes?:
The importance of choosing the right magnetic separation rack
The growing demand for cell sorting protocols is putting a lot of pressure on scientists, both in academy and industry. Great efforts are made to select the right markers and magnetic beads to ensure their correct attachment to the desired cells. However, all these efforts go to waste if the wrong magnetic separation rack is used. With inhomogeneous magnetic force system is difficult to distinguish when cell sorting problems are caused by the biomarker or the separation process itself.
The IVD industry has faced similar problems the last decade. These problems have become critical when the scale of the biomagnetic processes had increase to meet growing demand. R&D and Production departments needed biomagnetic separation equipment that will enable them to be more efficient, validate processes, and which can consistently be scaled up (to tens and liters) and down (to microliters).
This demand has led to the development of homogenous biomagnetic separation systems. With special magnetic field profiles, these devices generate the right conditions (magnetic field and magnetic field gradient) for applying homogenous magnetic force to the entire working volume.
Having a constant magnetic force, these advanced biomagnetic separation systems solve simultaneously the three major issues on cell sorting.
1) Higher recovery and faster separation
Homogenous magnetic force implies a stronger force farther from the retention area than that exerted by classical magnetic separators. The cell sorting process is therefore quicker and cell recovery rates are higher, as the magnetic beads attached to the cells experience a stronger force.
2) Increased viability of the cells
Homogenous magnetic force implies a gentler retention force, as you don’t need to increase it to assure fast separation and high recovery. As the force is constant near and farther from the retention area, it is easy to optimize it. Getting enough force to keep beads retained while extracting the supernatant –but not more- means having a higher force over the farthest beads if we compare with a classical (inhomogeneous) magnetic rack.
This gentler magnetic force over the retained beads (attached to the selected cells) avoids the risk of crashing the cells, highly increasing the viability of the selected population. The solution is valid for a wide range of bead diameters and magnetic content.
3) No undesired lyse due to constant force along ALL the biomagnetic separation process
Homogenous magnetic force also means that all the beads attached to the cell membrane experience the same force and move at the same speed. Then, is not stress on the labelled-cell membranes, avoiding the risk of undesired cell lyse during the separation process.
4) Well defined force allows specifying and validating the biomagnetic separation conditions, regardless protocol volume
A well-defined homogenous force value means that the cell magnetic sorting process conditions are well established. Magnetic field profiles generating the same magnetic force can easily be replicate at different volumes, from ml to tens of liters. Even when small tubes are introduced in a large volume, the magnetic force experienced by the labelled cells remains the same. Recovery rates would be constant and cell viability consistent across the different volumes. Just the separation time would need to be changed as -at constant speed- it is proportional to the beads travelled by the beads in the vessel.
Last, but not least, as the force is well defined (the value is constant throughout the working volume), different values can be tested to optimize conditions: larger for faster separation or lower for gentler conditions. For special magnetic beads or viscous media, it opens a way to overcome the limitations of the classical magnetic racks.
As conclusion: to ensure optimal performance of the magnetic cell sorting, you should not only select the right beads to capture and isolate your cells. You also need to pay attention of the magnetic rack you plan to use. If you select a Biomagnetic Separation system with a homogenous magnetic force, you will have well defined conditions, gentler retention and faster separation. The value of the force should be carefully selected to ensure high recovery rates and gentle retention with a wide range of beds and volume.
You can find additional information at our Biomagnetic Separation Blog and free eBooks and Technical Notes. Our technical team is also available to help you to find the best solution for your magnetic cell sorting process. In case you missed them, be sure to check these previously related posts:
- Magnetic cell separation processes in 3 steps
- 3 problems when using classical magnetic separation rack in cell sorting