I was about to order a tester-kit of streptavidin-coated magnetic beads from Invitrogen (4 different bead surface types, to find the surface that gives the least background), when I realized that these weren't the tiny 50 nm beads I had in mind but 1 µ beads that are as big as H. influenzae cells. I don't want to use great big beads if I can get smaller ones (yes, I realize that 1 µ is hardly 'great big').
Now I can't find the supplier that had the 50 nm streptavidin-coated beads at all. The best I can find is a European company, Ademtech, that has 100 and 200 nm beads. I've sent them an email asking if they have a Canadian supplier, but I'm not optimistic. Maybe I should just try the tester kit of big beads, and then scale down...
Invitrogen charges more than $500 for a stand that holds 16 microfuge tubes against rare-earth magnets, to separate the beads from the liquid they're suspended in. The 6-tube one is only about $150. But, I can buy a sampler of 50 NdFeB magnets of assorted sizes (1/8 inch to 1/2 inch, rods and discs) from Lee Valley Tools for $16.50.
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