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WGA-Alexa 488 Stock Preparation

  • Version: v1.1
  • Last modified: 2026-07-29

Preparation and storage of the WGA-488 stock. For the staining procedure itself, see Cell Membrane Staining (WGA).

Product Information

Property Value
Product Wheat Germ Agglutinin, Alexa Fluor 488 conjugate
Catalog Thermo Scientific W11261 (or S33667, 1 mg)
Fluorescence Ex/Em = 495/519 nm (green, FITC channel)
Specificity N-acetylglucosamine (GlcNAc) and sialic acid
Storage -20°C, protected from light; stable ≥1 year

1. Stock Solution (2 mg/ml)

  1. Warm up: Bring WGA-488 (1 mg) to room temperature for ≥30 min before opening -- opening a cold vial condenses water into the powder.
  2. Centrifuge: Brief low-speed spin to collect condensation.
  3. Dissolve: Add 500 μl sterile ddH₂O → 2 mg/ml stock.
  4. Aliquot & store:
    • Short-term: 2--8°C
    • Long-term: 10--20 μl per tube at -20°C, protected from light
    • Avoid repeated freeze-thaw; aliquots are stable ≥1 month

2. Before Every Use

Always clarify the stock -- this is the main background control

  1. Warm the aliquot at 37°C for a few minutes to redissolve precipitate.
  2. Centrifuge 10,000g for 1 min and take the supernatant only.

Precipitated conjugate is the dominant source of speckled non-specific background, and in flow-cell use it also clogs tubing.

3. Working Solution

Diluted fresh at the bench, in the staining protocol -- not stored. Target 5--10 μg/ml in PBS (1:400 to 1:200):

5 μg/ml:  2.5 μl stock (2 mg/ml) + 997.5 μl PBS
10 μg/ml: 5 μl stock (2 mg/ml) + 995 μl PBS
  • Buffer: PBS. Avoid cell-culture media -- it raises non-cellular background.
  • If background is too high, reduce the concentration; if signal is weak, increase to a maximum of 20 μg/ml.

Where This Is Used

Changelog

  • v1.1 -- 2026-07-29 -- Narrowed to stock preparation, storage and pre-use handling; the staining procedure, which was duplicated here, now lives only in Cell Membrane Staining (WGA). Page added to the site nav under Materials & Reagent Preparation (it was previously unreachable).
  • v1.0 -- Combined stock preparation and staining protocol.

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