Europium Conjugation Kit FAQs

1. What are the advantages of using our Europium Conjugation Kit?

The Europium chelate microspheres have been specially treated to enhance the handling of the beads and permit easy covalent attachment of antibodies and other proteins. The conjugation reaction is initiated simply by adding a solution of the antibody to the lyophilized mixture; the hands on time is 3 minutes and the conjugate is ready to use within 35 minutes.

Microspheres can sometimes encounter environments that cause unwanted aggregation both before and after conjugation, and harsh methods such as sonication or vortexing are routinely needed to resuspend both conjugated and unconjugated particles. Our special treatment significantly improves the handling of the europium particles and vastly reduces their propensity to aggregate. Harsh resuspension methods are not required, and recovery of usual mono-disperse europium particles is very high.

2. What type of linkage to the europium particles is formed?

The europium particles are specially treated, allowing the antibody to become covalently attached via lysine residues.

3. Does the conjugated antibody bind to the europium particle surface?

The antibody does not become directly bound to the surface of the europium particle, but instead becomes attached to the specially treated shell. This shell prevents direct interaction between the antibody and the surface of the europium particle, and for this reason our europium particles cannot be used for passive conjugation.

4. How many europium beads are in each kit?

Each vial of freeze dried material will provide 40ul 1% conjugated particles. In the 4 reaction kit there is 160ul 1% particles in total and in the 10 reaction kit there is a total of 400ul 1%. 40ul 1% europium beads should provide enough conjugate to perform up to 400 lateral flow assays.

5. How can I increase the signal to noise ratio in a lateral flow assay?

To increase the S/N ratio we recommend to wash the strips using a buffer containing a small amount of detergent and a blocking agent.

6. What if I need bulk material?

The Mini kits are convenient for rapid production of small quantities of conjugate for screening purposes. The Midi kits are ten times the size of the Mini kits for medium scale work (e.g. ~4,000 lateral flow tests). Bulk quantities can also be produced to meet your custom needs. Please contact us to discuss your bulk or custom conjugation needs or if you require any additional information.

7. Can antibodies from different species be used?

Yes. We have tested antibodies from a variety of species including mouse & goat.

8. Can monoclonal and polyclonal antibodies be used?

Yes. Our Europium Conjugation Kit has been developed for use with both monoclonal and polyclonal antibodies.

9. Can antibody fragments and non-antibody proteins be conjugated?

Yes – one of the advantages of the protective coat is that it is less likely than a bare surface to cause denaturation of antibody fragments and other proteins.

10. Is the kit suitable for conjugating small molecules including analytes?

The Europium Conjugation Kit has been optimized for use with antibodies, but it may be possible to conjugate small molecules with primary amine functional groups. Please contact our technical support team for information and support.

11. What can I do if my antibody is not in a compatible buffer?

The conjugation reaction is sensitive to a number of common buffers and buffer additives. The antibody should be in 10 – 50 mM MES, MOPS or HEPES at pH 6 – 7 for conjugation. As these are not common storage buffers for antibodies and other proteins we have developed the companion product the Antibody Concentration & Clean Up Kit for Latex and Europium to switch the antibody buffer to one that is optimal for conjugation efficiency.

12. What can I do if my antibody has non-antibody protein components or is not purified?

To remove contaminating proteins before conjugation, or to purify your antibody from ascites fluid, serum or tissue culture supernatant please see our AbPure range of purification products.

13. Can I use the Europium Conjugation Kit for Förster resonance energy transfer (FRET) application?

No. Our Europium Conjugation Kit has not been developed for FRET since the 200nm Eu particles will interfere with the fluorescence of the acceptor molecule.

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