Washing MAGPIX beads with the AquaMax 2000/4000 Microplate Washer and LifeSep magnetic plate holder
- Optimized washing for high-throughput bead-based multiplexing
- Excellent retention of washed beads
- Highly adjustable wash settings for maximum flexibility
The MAGPIX multiplexing system offers high-throughput multiplexing capabilities with up to 4800 results in one hour. To ensure optimal performance of these assays, it is essential to wash the MAGPIX beads efficiently while maximizing retention of the beads within the microplate wells. With the AquaMax® 2000/4000 Microplate Washers from Molecular Devices®, bead retention of at least 95% is achievable using the optimized settings described in this document.
Figure 1. AquaMax 4000 Microplate Washer using the MAGPIX multiplexing system and a LifeSep magnetic plate holder.
- MAGPIX Calibration Kit (Life Technologies, Cat. #MPX-CAL-K25)
- Phosphate buffered saline (PBS)
- LifeSep 96F magnetic plate holder (Dexter Magnetic Technologies, Cat. #2501008-1)
- 96-well clear microplates (Greiner)
- ImageXpress ® Velos ™ Scanning Cytometer (Molecular Devices
Step 1. Diluted beads 1:50 in PBS and pipetted 100 μL beads into each well of a 96-well microplate.
Step 2. Read the microplate on the ImageXpress Velos Cytometer prior to washing to obtain the starting number of beads.
Step 3. AquaMax Washer microplate setup: Created a new plate in the onboard software. Started with 96-well Greiner plate, entered height as 24.2 mm (regular plate height + 10 mm LifeSep adapter height). Used the Well Depth Auto feature to determine the precise well depth and saved the resulting value in the plate definition.
Step 4. Washed plate with PBS on the AquaMax 4000 Washer. The following parameters gave the best results (minimal loss of beads during wash):
- Position: Edge
- Rate: Medium
- Descent speed: 3
- Height: 5 mm
- Volume: 150 mL
- Rate: 5
- Repeat 2X from step 1.
- Aspirate (settings as above)
With the ImageXpress Velos Scanning Cytometer, fluorescence was scanned using the 532 nm laser. The number of objects detected per well before and after washing was determined using the ImageXpress Velos Cytometer software.
Pre-wash bead counts for 96-well microplate
Average number of beads per well = 615
Post-Wash bead counts for 96-well microplate
Average number of beads per well = 585
% Retention = 95.1
Figure 2. Images of pre- and post-wash representative wells. A. Pre-wash representative well: d5, 633 objects (beads) counted. B. Post-wash representative well: D5, 605 objects (beads) counted.
A high rate of bead retention is essential for successful MAGPIX multiplexing assays. When MAGPIX beads were washed in a 96-well microplate on the AquaMax 4000 Microplate Washer, using the LifeSep magnetic plate holder and optimized settings as described above, 95% of beads were retained in the wells. The AquaMax Washers’ highly adjustable settings and interchangeable wash heads offer the ultimate in flexibility and optimization for any assay.