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When using biomagnetic separation, in order to ensure the consistency of the resulting product and the process itself, there must be some sort of validation procedure. Validation should be consistent within a given lot, from lot to lot and also when the process is scaled up. The validation procedure should optimally be related to the conditions of magnetic bead separation and not be dependent on any specific device that generates the magnetic field.

Validation of magnetic bead separation must be independent of the device

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 Magnetic Bead Separation Processes:

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

Why should validation be independent of the device?

If the process is validated in a specific magnetic separation device that generates an unvalidated, unknown magnetic field pattern, it will be virtually impossible to scale up the process without revalidating every single aspect of the production. Furthermore, if the magnetic field profile is known, but the Magnetic Bead Separation conditions are not homogeneous, it will be very difficult to guarantee consistency in the lot and from lot to lot.

Within the lot itself, magnetic beads will experience very different conditions depending on their distance from the magnets. Beads close to the magnet will experience high forces over a long time and beads farther from the magnet experience variable forces. This leads to variability in the final product and an inability to translate the production data from one device to another.

In most magnetic bead separation devices, magnetic field changes depending on distance

Is there a way to make the validation process more straightforward?

Indeed, using a homogeneous separation system, the parameters of the process are easily measured and monitored, allowing one to create standard curves and optically watch the process over a period of time in real time. Several parameters should be considered:

  • The magnetic field should be high enough such that the beads are near their magnetic saturation point. Standard magnetite beads, for example, are saturated at B>0.1 T. Magnetic fields over 0.1 T are enough to magnetize the beads near ms, but realize that other types of paramagnetic material may require different field values.
  • The magnetic field gradient should be steep enough to retain the beads when the liquid is removed, but not steep enough to induce irreversible aggregation.
  • Finally, cylindrical geometries will allow regions with non-perfect conditions to be very small compared with the full volume. Any small force or agitation will easily push the beads that exist in this small non-perfect zone into the homogenous region.

Cylindrical geometries allow a more homogeneous magnetic bead separationIf 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

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Lluis M. Martínez | SEPMAG Chief Scientific Officer

Founder of SEPMAG, Lluis holds a PhD in Magnetic Materials by the UAB. He has conducted research at German and Spanish academic institutions. Having worked in companies in Ireland, USA and Spain, he has more than 20 years of experience applying magnetic materials and sensors to industrial products and processes. He has filed several international patents on the field and co-authored more than 20 scientific papers, most of them on the subject of magnetic particle movement.

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