Magnetic Beads - Incubation - (Dec/15/2009 )

Hi all,

I have another rookie question for you folks that make use of magnetic beads. I use 1.5 mL Eppendorf Tubes for pretty much all of my steps and whenever I incubate overnight with my magnetic beads for the IP step, after a few hours many of the magnetic beads seem to accumulate at the interface between the eppendorf tube top and where it makes contact with the inside of the tube. I place the tubes on an orbital shaker in our fridge in a horizontal orientation to ensure that the solution is gently mixed throughout incubation; but like I said over time the beads slowly accumulate at the top of the tube. What does everyone else use? My volume for IP is around 0.5 mL. Are there better tubes out there to use for this step where I don't have to worry about the beads accumulating in one place?

Thanks in advance for your response!

MM

I'm using "standard" 1.5ml Eppendorf tubes and also a volume of 0.5ml. Never had any problems with beads sticking to them. Having said that, I'm using a vertically rotating wheel. Maybe you should try a similar 360 rotation, or if unavailable, increase the speed setting of your shaker, as a horizontal position will inevitably mean that gravity causes the beads to sediment on one side of the tube...

jhb80 on Dec 15 2009, 10:00 AM said:

hi MM,

I was using a similar improvisation setup like urs...but used to tape the tubes on to a vortex machine in a slanting position (around 20-40 degrees) so that it never goes up to the cap but still it keeps shaking in a low speed..never had a problem of beads settling down too..I was using 1.5 ml tubes with 240 ul volumes.