Biomagnetic Separation - Magnetic Bead Assays | 91
the between-cycle soak time to improve bead separation during processing.
l Shake/Soak Step: Begin the protocol with a delay to let the magnetic beads settle.
Also, specify a mid-cycle soak to let the beads settle after fluid is dispensed to the plate,
e.g. include a 60 second soak before and between cycles.
Include a 1 second Shake in the first step to best position the plate.
l 6CW Aspirate Travel Rate: select 6CW for the aspirate travel rate. The CW travel
rates are designed to minimize disruption to cell layers on the bottom of the well. The
same principle applies to magnetic bead assays.
l Adjust the Aspirate height: increase the aspirate height setting (Z-axis) which will
increase the residual fluid in the wells but also preserve the beads. Good results were
obtained when keeping the aspirate height around 1.0 mm above the plate carrier for all
but a last Final Aspirate (disabled between cycles).
l Adjust the Aspirate position: When using Flat Magnets below, position the aspirate
tubes near the sides of the wells (X-axis), if possible, to improve bead retention.
l As always, before running assays, we recommend testing new protocols using deionized
or distilled water and a little Tween
®
20 with the desired microplate and a magnet
installed.
Flat Magnets
Use this information about the flat magnets to fine-tune wash protocol settings:
96F Magnet 7103016
384F Magnet 7103017
The 96- and 384-well magnets are structured differently. Their force fields traverse
the magnet in opposite directions. Magnetic beads in the wells will be drawn to the
center. For the best bead retention, reposition the aspirate tubes in the proper axis:
96-well Flat Magnet PN 7103016
The magnetic force (approx. 6800 Gauss)
is distributed in a horizontal pattern,
row-wise, across the plate. Magnetic
beads are pulled to the center, across the
well in flat-bottom plates and to the
button in round-bottom plates. Increasing
the aspirate height to increase the
amount of residual in the well may
improve performance.
BioTek Instruments, Inc.
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