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.
Magnetic separation is a breakthrough technique for in vitro diagnostics (IVD). Scientists, hospitals and companies have taken advantage of the magnetic separation process for immunoassays, molecular diagnostic and genetic testing systems and kits. However, this type of technology is typically utilized by the end-user in very small quantities.
In-lot consistency is the key to reproducibility at the level of a kit. Unfortunately, in non-homogenous systems irreversible aggregation is one of the main sources of in-lot variability. If all of the beads are exposed to the same force as they are in homogenous magnetic systems, the risk of aggregation is greatly reduced. Because of this, it is important to know how to avoid irreversible aggregation problems during a magnetic separation process.
A recognized problem in the biomagnetic separation industry is that when one increases the batch size to scale up production of magnetic beads, the magnetic separation process time increases unproportionally to the increase in volume if one is working with standard magnetic separation devices.
One of the biggest problems of producing magnetic beads when scaling up the production is that compared with smaller lot production, larger lot production seems to result in a much larger disproportionate loss of beads. This seems to happen even when the beads are produced in conditions that are similar to the small lot production in a magnetic separation process. The assumption is that when you scale up a process, you will have greater efficiency, but this does not happen when scaling up production of magnetic beads using classical separators.
It is understandably important to end users that every kit within a particular lot have the same properties. In other words, when one is producing lots of material to be used in an IVD kit, one necessarily strives for maximum reproducibility and minimal variability. With standard magnetic separators, it is very difficult to achieve this goal in a magnetic separation process.
Often when a lab produces a product that becomes popular, the impetus is to move forward and scale up production of that product. The problem is that moving from the production of small lots to full scale production usually produces surprising results. Scaling up is not trivial, and the magnetic separation process is no exception. When one scales up production, results become very inconsistent.
What are the problems of the classic magnetic separation process? Typically the classic ways to produce magnetic bead reagents and kits are slow, very high maintenance and costly to run. The three classic techniques, centrifugation, filtration and tangential filtration, are not straightforward techniques.
Scientists in academic research labs and pharmaceutical labs perform magnetic separation process with magnetic bead kits for immunoassays and separation science. Doctors, lab technicians and scientists use magnetic beads in IVD kits as molecular diagnostics devices.