Recommendation - which of these eGFP/FITC filter sets?
We need to add a new cube to our Olympus BX61 (metal halide light source) with a filter set/dichroic for eGFP and FITC. We’ll also have mCherry expression in some samples which we don’t want to bleed into. We have quotes for:
Spectrally they all look similar on the FPBase Spectra Viewer so do we just go for the cheapest (although they’re all similar in price) or are there other differences that we should take into account? Thanks.
Thorlabs’ filters appear to be rebranded Semrock filters, at least that set. Compare the %T curves’ peaks and valleys, on their web sites. Good deal there.
I would not choose the Newport, at least not that part#. The %T graphs for excitation and emission filters seem to be touching each other, i.e. when each is on the order of .01 (1%). If you dig deeper into the transmission curves for the other 3 choices – looking at them on a log instead of linear scale (you’ll have to download the Thorlabs Excel file)-- you’ll see that they don’t touch until each is on the order of .00001. That’s roughly a million-fold difference in terms of blocking any reflection coming back to the image plane, although just in that small wavelength band where they cross. It can make a difference. Semrock is perhaps the best in this regard, at the expense of some loss of brightness.
You’ll notice that Newport on their website doesn’t show their transmission curves on a log scale.
Of course there are other considerations, like bleedthrough, as you mention. You should be safe with mCherry or spectrally similar probes.