When a non-homogenous magnetic separation rack (a classical system) is used for scaling up a process, the conditions for a larger batch will completely change from the smaller batch. In these classical non-homogeneous magnetic separator, both the magnetic field gradient and the magnetic state of the beads (either linear or saturated) will vary depending on their position and relative distance to the magnet.
This post is about biomagnetic separation with a magnetic separation rack, and how to scale-up this process. If you are interested in this topic, download our free ebook The Basic Guide to Scale-up Biomagnetic Separation Processes:
Magnetic bead behavior in a magnetic separation rack
Beads in a smaller field will have linear characteristics and beads in a higher field will be saturated. The magnetic field gradient also varies, often varying maximally at a particular distance and then becoming less variable again at a greater distance.
Even if the force distribution is good enough to generate optimal characteristics of the product (i.e. small losses with no irreversible aggregation), the use of a different device, either larger or smaller, all the parameters previously determined or observed will completely change for the new magnetic separation rack. The force experienced, for example, by a particular percentage of beads will be different from one device to the other and will depend on their relative position to the magnets.
This happens because the magnetic state of the beads will change due to the differences in the magnetic field intensity. It will be very difficult to reproduce the parameters over the entire new volume with a non-homogenous system. Because of this, the characteristics of the lot will be completely different from the initial lot. There will be greater aggregation and coating problems among other difficulties. And while it is possible that the final product’s functionality will not be changed in any appreciable way, more often than not, variations of the magnetic force due to a different device has a huge impact on the performance of the final product.
Magnetic bead behavior in advanced systems
In homogeneous biomagnetic separation systems, you have more control over the conditions since the parameters are well defined and easy to reproduce at various scales of production. Therefore the problems normally seen in scaling up with non-homogeneous systems do not manifest in homogeneous systems.
Don't forget to check these posts from our blog in order to get a deeper insight into the scaling-up of biomagnetic separation processes:
- Why do Larger Non-Homogeneous Magnetic Separators Have Higher Losses of Magnetic Beads and Biomolecules?
- Why are there More Magnetic Bead Irreversible Aggregation Problems in Non-Homogeneous magnetic separators
- When Scaling Up Biomagnetic Separation, Should You Use Electromagnets or Permanent Magnets?