Dear Veronica,

does this help?

http://eylabs.com/product/protein-a-fitc-colloidal-gold-1ml-5nm/

Never testet it, though.

Regards,

Andreas

Dear Andreas,

Thank you very much for your answer.

I found it by myself yesterday after looking for some time. I think it is the only possibility, then.

If I will test it, I will post the result.

All the best,

Veronica

An alternative would be to label first with the Protein A gold and then with a secondary antibody with an Alexa. Since the gold is relatively big it will leave enough binding sites for the small Alexas.

Regards,

Andreas

The protocol can be found here: Article Outer Segment Formation of Transplanted Photoreceptor Precursor Cells

Thank you very much, I was considering this kind of alternative too.

What would be the most interesting one in your opinion? the protein A could be considered quasi-quantitative?

If you have the protein A Gold and an Alexa coupled secondary antibody at hand already you could just try it. At least the Protein A Gold will not be influenced by the secondary antibody.

I think people can have long discussions on how quantitative Protein A Gold really is. But if you have a big effect in your experiments it will be a good tool to quantify that.

Regards,

Andreas