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Posted on Tue, Feb 19, 2013

4 steps to validate the homogeneity of your biomagnetic separation process

Biomagnetic separation needs validation in order to ensure reproducibility. The skills necessary to identify the key parameters affecting separation performance, measure those parameters, and enact the appropriate controls are specific and require an excellent background in physics.

Magnetic bead separation needs validation to ensure reproducibility

Most magnetic bead separation industries take the easy road in order to validate their processes. They determine, by trial and error, the correct separation time. While this strategy is fine for one volume and one type of product, this does not work when scaling up production. Production after scaling up is then delayed until new conditions are defined, again by trial and error.

This post is about magnetic bead separation and how to validate this process. If you are interested in this topic, and are willing to learn more about it, download our Free Guide The Starting Guide to Validate Biomagnetic Separation Processes:

Free PDF guide:   "Validation of Magnetic Bead Separation Processes" 

Steps to validate magnetic bead separation

Ideally, validation of a biomagnetic process should proceed by identifying and measuring key parameters such as the state of the magnetic beads and the magnetic field profile. The following are suggestions for correctly validating biomagnetic separation production:

1. Check magnetic bead saturation levels

Fields over 0.1 Tesla will be enough for standard magnetite beads to acquire a magnetization near ms. Different materials will need different magnetic field saturation levels.

2. Make sure the magnetic field is b enough

Multiply the gradient by the vessel radius. The value should be much higher than the field necessary in order to saturate the beads.

3. Make sure the magnetic field gradient is large enough to retain the magnetic beads

The magnetic force depends on both the field gradient and the moment of the magnetic beads. This value should be large enough to retain the beads at the wall of the vessel while removing the liquid completely. If you need a greater magnetic force, you will need to increase the magnetic field gradient.

4. Evaluate the ‘non perfect’ region and make sure it is small relative to the rest of the volume

Magnetic field gradients will vary. A large magnetic gradient implies that in some areas, your magnetic field can be lower than that necessary to saturate the magnetic beads. Make sure this region is small enough that the beads can easily leave this region.

Cylindrical vessels are the best shaped vessels to use. If the magnetic field gradient is radial, the volume of the sample in the ‘non perfect’ region is in the symmetry axis and any small force or agitation will push them out of the region. The volume also depends on r2, so, for example if 10% of the diameter of the vessel dips below 0.1 Tesla, it implies that only 1% of the sample volume is exposed to these conditions.

Cylindrical vessels are great for magnetic bead separation

If you do not how to put in place these 4 ways to validate the homogeneity or similarity of your biomagnetic separation process, you can look for advanced biomagnetic separators that do it for you.

If you found this article interesting and want to get a deeper insight in the topic of magnetic bead separation, make sure to check these articles from our blog:

Dr. Lluís Martínez

biomagnetic separation processes

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