A very common problem that occurs when scaling up non-homogeneous magnetic separation processes in a magnetic separation rack is irreversible aggregation of the magnetic beads. When the process is scaled up, the magnetic force experienced by the beads closest to the magnet is very high.
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:
How to solve irreversible bead aggregation
Since the separation time typically must be increased in larger volumes in order to increase bead yield, the risk of irreversible aggregation and clump formation greatly increases. This can decrease yield and functionality of the beads by damaging the beads or by damaging the biomolecules attached to the beads. In addition, not all of the clumped beads will be recovered.
The main way to rid your production run of irreversible aggregated clumps is to use repeated cycles of sonication and homogenization. However, this implies the addition of several steps to the process, invest in new equipment, and additional QC points to ensure the re-suspension is correctly done.
The ideal way to deal with aggregation is to avoid it completely. You can avoid irreversible aggregation by decreasing the magnetic force in the retention area. In you are using an inhomogeneous magnetic separator rack, reducing the magnetic force near the magnet decreases the force felt by distant beads in a non-linear fashion. Unfortunately, this can lead to greater material losses and much longer separation times.
Advantages of advanced biomagnetic separation devices
Optimally, you can use a homogeneous biomagnetic separation device where the magnetic force remains constant throughout the entire volume of the vessel. This makes it possible for you to reduce the magnetic force in the retention area without decreasing the force significantly over the beads that are more distant from the magnets.
If your constant force is gentle enough, it will be below the irreversible aggregation force threshold. Even though this force is considered ‘gentle’, the force experienced by distant beads is still much higher than that experienced by distant beads in standard inhomogeneous magnetic separation rack. Therefore, homogeneous biomagnetic separation devices can speed separation while at the same time decreasing or eliminating clumping.
Please note that while we are talking about gentle retention forces in homogeneous systems, the force should still be high enough to avoid excessive loss of beads that may remain in the supernatant. SEPMAG systems are designed to allow you to easily eliminate clumping, reduce separation times and at the same time, avoid undue loss of material.
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:
- The secret to avoid magnetic bead (and biomolecule) separation losses when scaling up
- How to avoid In-lot inconsistency when scaling up biomagnetic separation processes
- Keeping lot to lot consistency when using biomagnetic separation at different volumes