Recently I bought a shiny new piece of lab equipment. It is essentially a strong neodymium magnet with 96 holes, so that you can place a 96 well reaction plate in it.
It is used in DNA purification: You bind the DNA in the wells of the reaction plate to tiny metal beads, place the reaction plate on the magnet plate and presto! within seconds the beads are drawn to the walls of the wells. Now you can remove the liquid that contains everything but the DNA and the beads, wash the well, and then put pure water or elution butter in each well. You remove the reaction plate from the magnet, let the DNA go back into solution, and then you use the magnet once more to separate the metal beads from the water which now contains your cleaned DNA.
Two things are remarkable about this magnet plate. The first is how heavy it is compared to its small size (and considering the fact that a lot of it is holes). If you pick it up, you really have something in your hand.
The second is the product description slip that came with it. Because this magnet is really super strong, it contains a lot of colourful warnings:
Individuals with pacemakers or implantable cardioverter-defibrillators should avoid contact with this product.Not surprising. I remember that the university where I studied had entire corridors with warning signs telling people with pacemakers to keep out because strong magnets were being used.
Do not allow the unit to come in contact with metal objects or other magnets. Damage will occur to magnetized media, such as diskettes or credit cards, near the plate. Damage will also occur to computers and CRT-based monitors near the magnets.Unsurprising again, and clearly I will not use it on a bench where we have cyclers or other expensive equipment.
Under no circumstances should two magnet plates be allowed to "snap" together; the magnets are strong enough to cause injury and separating them is almost impossible.In other words, anybody having fingers between two of those plates would find reason to regret it. However, I would assume that most average labs do not need more than one of these plates anyway.
Obviously this item needs some thoughtful handling. But at the moment I am mostly impressed by the strength of its magnetic field - and by the fact that we measly humans are able to manufacture something like it.