What is the sensitivity of the RayBio® Cytokine Antibody Array? Can your systems detect cytokines present in culture medium at low pg/ml? Is there a difference in the sensitivity among the cytokines that are detected by the assay?

Would you have a reference list of publications citing your arrays ?

Yes. You can click here to have access to this list of references citing our antibody arrays. http://www.raybiotech.com/Reference_List.asp.

Is this a quantitative assay?

The antibody array membranes provide information on relative changes in cytokine levels. Results are provided as ratio relative to a control group. It is a semi-quantitative assay.

What are the tissues that have been tested so far on your arrays?

Our records indicate that the following tissues have been successfully tested: lung tissue, bronchia, endometrial tissue, liver, spleen, brain, and skin tissue

Is there any cross-reactivity between the RayBio® Cytokine Antibody Array and any bovine cytokines found in FBS?

Not all cytokines were tested. Most tested cytokines do not cross-react with bovine cytokine. However, some cross-reactivity was seen, such as IL-8, G-CSF and TGFb. We urge our customers to use low serum-conditioned medium for the experiment. If high serum is necessary, run a control experiment at the same time.

What is the size of the membranes?

The membrane is approximately 2x3 cm (from 2.5X3 cm to 2x2.5 cm). It fits into an 8 well tissue culture plate. MMPs arrays are 2 x 1.2cm.

How do you recommend storing the samples prior to use on the arrays?

We recommend storing the samples at -80C until testing. Fresh samples are best, but are not required. In fact, most investigators use frozen samples.

How much sample do you need to use for each array?

I would like to recover the signal from a used chemiluminescent membrane. Is there any way I could do this?

Yes. As long as the membrane has not been dried (but was kept frozen in a plastic wrap), you can wash it with Wash Buffer II, proceed with HRP conjugated-streptavidin incubation at 4°C O/N and follow the protocol from then.

I would like to repeat the last steps of the procedure (detection), will I have enough reagents?

We usually include enough reagents for one extra detection step. However, If you require more ragents, we do supply separateley "Accessroy Kits" including the HRP-streptavidin conjugate, the wash and blocking buffer (+/- lysis buffer) and the detection reagents for each array format: either for cell lysate or for conditioned medium.

Can one strip and reprobe the membranes?

Some of our customers are trying to reprobe the membranes. However, this is not a procedure that we would recommend.

What are the positive and negative controls spotted on the membranes?

Negative controls are PBS only. Positive controls are biotin labeled protein spotted on the membrane.

Have you got special recommendations for data analysis?

One specific analysis tool is available for each array reference to help you analyse your data more quickly. They can also be provided upon request for custom array orders.

If you experience uneven signal

• Make sure to always use forceps to handle membranes
• Do not allow membranes to dry during experiments
• Completely cover membranes with sample or buffer during incubation and avoid foaming.

If you experience high background

If you experience weak or no signal