When magnetic bead reagents are produced in quantity, often you cannot know if you have the correct properties of the beads until the final quality control step. But if these properties are wrong, finding out the properties at the end of the magnetic separation process for production does not allow you to salvage the lot. Knowing magnetic bead properties, such as size, magnetic charge and surface charge, is critical in order to have excellent reproducibility in the final product (e.g. IVD kits).
If scientists and technicians link their production results solely to the separation time on one specific piece of classic biomagnetic separation equipment, they will not be able to translate that success. This is applied to both different batch sizes or even the same batch size on a different piece of equipment, unless they optimize the separation time for the new conditions.
When a lab has finally optimized their production process, they often link their process to a very specific piece of equipment and, by extension, have locked themselves into a constant volume. Often a lab develops its magnetic separation process for production with a specific magnetic separation device – this is normal. Usually the only parameter that needs to be adjusted during production is the separation time.
Classic magnetic separation equipment requires a large amount of space in order to comply with health and safety regulations. While the magnetic separation process has numerous advantages, the magnetic fields surrounding the devices may be so large that they fall within the ‘danger’ and/or ‘caution’ areas.
The separation time in standard magnetic separation devices is usually determined by analyzing aliquots of solution taken at different times. The problem is that each aliquot gives the technician information about one spatial point in time. Therefore, the design of validation experiments becomes a very complex endeavor.
When using biomagnetic separation systems, customers are always curious about how to comply with the various health and safety regulations that are in effect. When customers use small systems for a small scale magnetic separation process, there is very little risk from the magnets. The only risk would be if the technician has a pacemaker and in that case, they would be extremely careful around even the smallest system. There is also a small risk of pinching one’s fingers between two magnets.
When scaling up a process using a traditional magnetic separation rack, the percentage of bead and biomolecule losses significantly increases with an increase in volume. One way of dealing with this problem is by applying a higher force at longer distances. But for this to work, you must apply this greater force without increasing the forces in the retention area during the magnetic separation process, in order to avoid irreversible aggregation.
If one wants to scale up production from small lab lots to full-scale large lots, a non-homogenous magnetic separation process will result in lot-to-lot inconsistencies. Homogenous biomagnetic separation conditions, however, guarantee consistent results regardless of production scale.
Due to the inherent properties of classic non-homogenous biomagnetic separators, beads can aggregate during the magnetic separation process. When this happens, technicians try to resolve the magnetic beads separation problem by using special resuspension techniques like the sonication method. But problems with resuspension can ultimately lead to end-product variability, especially if aggregation is not detected early.