The best method for washing magnetic beads is use of a magnet. However, magnetic beads can be washed using a vacuum manifold and a filter-bottom plate. Magnetic beads are actually larger than the polystyrene (6.4 vs 5.6 um) so there is little risk for the beads to be pulled through the filter with a standard filter bottom plate (Millipore, Cat# MSBVN1B50). Prior to reading the assay, add an extra shaking at the final re-suspension step to be extra sure the beads are free from the plate.
The following protocol is from Luminex:Stringent Soak Routine - MAGPIX Please perform a self-test and follow the steps below: 1. Go to Maintenance >> Cmds & Routines and run a Clean command with 0.1 N NaOH. After the sample is taken up in the chamber (after the probe comes back up from acquiring the reagent), press the stop button in the software, and then turn off the instrument (for 20 minutes or less, push the soft switch under the blue light). 2. If soaking overnight or over the weekend, turn off the instrument using the soft switch and power switch (back of instrument) after reagent acquisition. Also, power down xPONENT and the PC (to avoid connection issues when re-booting). 3. When soaking is complete, turn the instrument on first, then the PC, and allow connection to the software. 4. Run the Maintenance >> Cmds & Routines >> *Daily Fluidics Prep routine. 5. Run System Initialization for calibration and verification.
The difficulties of running multiplex beads in a flow cytometer is the inability to distinguish the different bead sets since they are stained with dyes that are optimally excited with a YAG laser. If a customer wishes to run a single bead population (IL-8 only for example), one would need the ability to discriminate different beads with different analyte capturing abilities. Also, since the bead assays are developed with PE-conjugated antibodies, the argon laser of most flow cytometers will be able to generate a signal from these beads. Keep in mind that this does not utilize the full potential of the Luminex Assay kits.