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Conjugates FAQs

Common technical support frequently asked questions (FAQs) about antibody-related conjugation answered by Creative Biolabs’s team of scientists.

  1. Can your antibody products be used for conjugation?
  2. Yes. Most of our antibodies can be used for conjugate generation, and we also provide antibody conjugation kits to help your conjugation projects.

  3. Do I need to purify the antibody before conjugation?
  4. Antibodies are widely used in the bio-conjugations, and the coupling efficiency depends on the antibody purification due to the buffer or buffer additives that can influence the conjugation efficiency.

    Our antibodies often are stored in different buffer forms such as PBS or PBS plus Sodium Azide or other additives. Thus, If the antibodies contain other buffer additives besides the PBS, we recommend your purify the antibodies before your conjugation. In addition, antibodies in ascites fluid, serum or hybridoma culture media are also not suitable for conjugation.

  5. What buffers and buffer additives can be used?
  6. Some buffers are compatible and incompatible for conjugation listed below:

    • Compatible buffers: PBS, Potassium phosphate, Sodium chloride, HEPES, Sucrose, Sodium citrate, EDTA, Trehalose, EGTA, MES, MOPS,
    • Incompatible buffers: Thimerosal, Proclin, Glycine, Arginine, Glutathione, DTT, Merthiolate, Tris, BSA, Glycerol, Sodium azide, Gelatin.

    If a constituent of the buffer containing your antibody is not shown above, you may contact us for more information and solutions.

  7. How do I remove additives from the antibody buffer?
  8. Generally, you can use an Antibody Concentration and Purification kits to remove additives. The kit can maintain your need concentration of antibodies and reduce of the concentration of azide, glycine, BSA and Tris. The Antibody Purification Kit can also be used to purify antibodies from ascites fluid or immune serum by binding the antibody to Protein A resin. Remarkably, the kit is not suitable for tissue culture supernatants due to their excess volume. Besides, you also can remove additives by the conventional buffer exchange method.

  9. What is the optimal starting concentration of antibody for conjugation?
  10. The optimal antibody concentration is 1mg/mL. If the maximum antibody volume is not exceeded, 0.5-1 mg/mL also can be acceptable. If antibodies concentrations over 5 mg/mL or below 0.5 mg/mL, which should be diluted /concentrated.

  11. How do I store the conjugates?
  12. Normally, a new conjugate can be stored at 4°C for 12-18 months if the antibody is stable enough at 4°C. The bond between the antibody and dye is covalent and very stable, thus, no additional preservatives are needed at 4°C. But if for long term storage at 4°C, we recommend adding antimicrobial agents and/or stabilizers (e.g. azide, BSA, glycerol, etc., and except that for HRP conjugates azide is not suitable). All conjugates can be stored at -20°C for 2 years with 50% glycerol. Importantly, APC and RPE conjugates can’t be stored at -20°C on their own without glycerol.

  13. Do I need to desalt the final conjugated antibody?
  14. No. Any our antibodies can be used in WB, ELISA, IHC and other applications, which can be used for conjugation straight away.

  15. How does the conjugate bind to the antibody?
  16. Usually, the highly stable conjugate is bound to the antibody via a covalent bond.

  17. Would conjugating a primary antibody with biotin affect its affinity with a secondary antibody?
  18. Generally, if your conjugation reactions use a low molar access/concentration of biotin, it should not affect the affinity with the secondary antibody. Additionally, most of the secondary antibodies are polyclonal in nature that can bind more than one epitope on primary antibodies.

If you still have other questions about conjugates, please directly contact us.

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For research use only. Not intended for any clinical use.