Technical FAQ

Guarantee and Storage

• How do you guarantee the quality of the antibodies?

Our QA tests ensure the quality of the antibody from lot to lot. All of our products are tested in relevant applications such as western blotting, immunofluorescence, immunoprecipitation, immunohistochemistry, flow cytometry and chromatin immunoprecipitation. Additionally, we routinely test our antibodies on multiple species, such as humans, mice and rats.

• How are the products packaged?

Most of our antibodies are shipped in 4°C refrigerated packaging, and some special products require packing and shipping on dry ice.

• What are the characteristics of polyclonal antibodies?

Production of polyclonal antibodies is rapid and inexpensive. They are non-specific because they recognize different epitopes on the antigen and are more tolerant of small changes in their properties. They are essential for the detection of denatured proteins.

• What are the advantages of monoclonal antibodies?

Monoclonal antibodies recognize only one selected epitope of an antigen. Monoclonal antibodies have high homogeneity and reproducible results.

• How should I aliquot the antibody?

Aliquot volumes will depend on the specific requirements of your applications. We recommend that aliquots should be no smaller than 10 µl, since the concentration in small volumes is more susceptible to external temperature and adsorption on the surface of the bottle.

• How to store antibodies properly?

Generally, antibodies are stored at 2-8°C for short-term and storage and -20°C for long-term storage. Aliquot and store before use to avoid repeated freeze-thaw cycles. Some special antibody products need to be stored in dark. We recommend storing antibodies according to the instructions on the datasheet to guarantee their performance.

Concentrations and Purification

• How does your antibody purify?

Our antibodies are purified using protein A or protein G affinity chromatography and ion exchange chromatography. In addition, anti-immunoglobulin antibodies or immobilized antigen purification is also available at Creative Biolabs.

• What antigen concentration is required to produce a specific antibody?

We recommend selecting an antigen concentration of 1 mg/mL or higher. If your antigen concentration is lower than 0.2 mg/mL, please contact us for a reasonable solution.

Applications

• What parameters need to be considered when preparing protein samples for western blot (WB)?

Samples should be lysed in an ice-cold buffer with protease inhibitors. Note that the samples to be tested are placed on ice or frozen to avoid multiple freeze-thaw cycles.

• What causes high background in the WB test?
• Concentrations of primary and secondary antibodies are too high.
• Insufficient blocking of non-specific binding.
• Too much of the sample is loaded.
• What causes the protein band to be different from the predicted molecular weight of the protein in a WB assay?
• Post-translational modifications may increase the molecular weight of the protein.
• Relatively charged amino acid composition.
• Isoforms resulting from alternative splicing.
• What can your antibodies be used for?

All of our antibody products are intended for research use only and are not intended for therapeutic or diagnostic use in humans or animals.

Conjugates

• How to choose a fluorescent conjugate?

In order to choose the right fluorophore conjugate, you need to consider several issues: which lasers are on your microscope and the number of fluorophores you plan to use on a sample.

• How do conjugates bind to antibodies?

Conjugates bind to antibodies through highly stable covalent bonds.

• How stable are conjugated primary antibodies?

Conjugated primary antibodies are stable for up to 18 months when stored at 4°C, and up to 2 years when stored at -20°C.