We are looking for pairs of fluorophores for protein labelling for FRET and two color experiments. They should be robust and inexpensive, since we wil use a lot.
FITC-Rhodamine is the one we have.
Which Alexas? (I would prefer options)
Also, we want to do two-color labelling of antibodies for immunofluorescence. So, two fluorophores that absorbe around similar wavelengths and emit at different ones.
G
Hi Gonzalo, rhodamine is an excellent choice. Stable and resistant to bleaching. FITC, not that much.
In my experience Alexa fluors 488, 555 and the Cy5 dyes are very dependable.
Alexa dyes are quite expensive, but are nice to use because they are charged and therefore have high water-solubility.
BODIPY dyes are considerably less expensive and are quite photostable, but are also hydrophobic.
The older dyes are the least expensive. Fluorescein-like dyes have poor photostability. Rhodamine-like dyes are typically better in this respect.
If you can use dyes with shorter wavelength excitation, you have many older dyes to choose from, such as EDANS and NBD, which have large Stokes shifts, and some can be paired as the acceptor with tryptophan as the donor.
It is difficult to find small organic dyes with similar long wavelength excitation maxima but substantially different emission maxima because the Stokes shifts are typically small for dyes with long-wavelength excitation.
Steingrimur Stefansson Thanks a lot!. I had not seen your reply
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