• Product name

    GOLD Conjugation Kit (40nm, 20 OD)
  • Product overview

    Abcam's Gold Conjugation Kit allows antibodies or proteins to be covalently attached to ultra-stable GOLD nanoparticles at very high OD quickly and easily. The hands-on time for the Gold Conjugation procedure is about 2 minutes and the conjugate is ready to use within 15 minutes. 

    The Gold nanoparticles in this kit are supplied as a freeze dried mixture. The conjugation reaction is initiated simply by adding a solution of the antibody, which becomes attached (via lysine residues) to the Gold surface.

    The resulting covalent conjugates are more stable than those prepared by passive adsorption methods. Moreover, unlike passive methods, the coating procedure is not dependent on the isoelectric point of the antibody, and extensive trials at different pH values are not required; all antibodies react at a single fixed pH.

  • Notes

    The 3 and 10 Test Conjugation Kits are designed to label 12 µl of antibody per vial.

    The 1 Test Conjugation Kit is designed to label 120 µl of antibody per vial.


  • Storage instructions

    Store at -20°C. Please refer to protocols.
  • Components 3 tests 10 tests 1 tests
    Gold 3 vials 10 vials 1 vial
    Gold Antibody Diluent 1 vial 1 vial 1 vial
    Gold Quencher Reagent 1 vial 1 vial 1 vial
    Gold Reaction Buffer 1 vial 1 vial 1 vial
  • Research areas


  • Please see the protocol booklet for a detailed method. 



ab154873 has not yet been referenced specifically in any publications.

Customer reviews and Q&As

1-3 of 3 Abreviews or Q&A


Thank you for getting in touch.

I can confirm that 40nm gold nanoparticles are the most popular choice for lateral flow assays. This is due to an optimal combination of high contrast colour which appears cherry red and surface area for effective and efficient analyte testing,

30nm and 60nm gold nanoparticle also have specific advantages depending on the design and application of the lateral flow test.

30nm gold nanoparticles have a darker red appearance that improves contrast against white lateral flow assay membranes compared to 40 nm spheres. With increased contrast, due to the smaller size 30 nm gold nanoparticle require more conjugated antibodies to achieve an equivalent mass concentration.

60nm gold nanoparticles have a lighter red appearance which trades contrast efficiency for increased optical absorbance per particle. Thus, less particles are needed to produce a measurable reading. This means 60 nm gold are ideal for immunoassays with low target analyte concentration samples, or when the targeting moiety is very expensive.

In addition to this, the following information may be helpful:

In principle, the smaller gold particles produce a higher labelling intensity. This is due to reduced steric hindrance to antigen detection.  For example, a 1nm gold particle, attached to the Fc region should not significantly affect antibody binding. A 20nm particle, however, while being more visible, will produce a greater steric hindrance. In addition, the increased charge repulsion between larger particles reduces the number of labelled antibodies gaining access to the target antigen.The surface of gold nanoparticles have free electron which resonate with the oscillating electric field of a light ray propagating near it, creating a concerted oscillation of electron charge called surface plasmons.

These surface plasmons will cause absorption and reflection of lights, and these absorption and reflection are dependent on the size of the gold nanoparticle. For smaller gold nanoparticle, the reflected light is red – whereas the bigger nanoparticle will start to absorb redder wavelength and reflects more blue wavelength, yielding purple or more blue colour. Since larger nanoparticles have a higher magnitude of absorption and available surface area for antibody conjugation, they can provide better assay sensitivity. However, when larger nanoparticles are used, absorption in the longer wavelengths reduces the contrast on the test strip.

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El termino OD se refiere efectivamente a la densidad óptica para el oro, que es la manera más común de expresar la concentración de las nano partículas de oro. La longitud de onda se mide a 530nm.

Me temo que no podemos proporcionar el equivalente en concentración, pero quizás os ayude saber que hay aproximadamente 9x1010 nano partículas por 50µl de conjugado.

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Thank you for your enquiry regarding ab154873.
I can confirm that the high isoelectric point of the protein should not be a problem when using ab154873: EasyLink GOLD Conjugation Kit.
The main points to bear in mind about the protein buffer prior to labeling with this kit are:
● Protein must be purified
● Avoid amino acids (e.g. glycine)
● Avoid other primary amines (e.g. Tris)
● Avoid thiols (e.g. mercaptoethanol, DTT)
● Avoid carboxylic acids (e.g. EDTA)

Your customer should also note that the protocol will be the same as when labeling an antibody. However, if the protein is significantly larger or smaller than a typical IgG (about 160kD) they might want to explore varying ratios of protein.
The optimum amount of antibody or protein in this case (which will influence the number of antibody/protein molecules per particle) may be application-dependent and you may need to conjugate different amounts of antibody to optimize your assay.
I would advise your customer to download the protocol booklet (click on the blue hyperlink bottom section on the on-line datasheet) and read the document carefully.
The initial amount of antibody recommended corresponds to 10ug antibody per ml of 10 OD gold, which is about half of that normally used for passive (non-covalent) conjugations. However lower or higher concentrations can be explored as there is no risk of aggregation because of the protective surface coat.
I hope that this helps. If you need any further assistance in the future, please do not hesitate to contact me.

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