Re: DsRed vs 2P

Posted by Kate Luby-Phelps on
URL: http://confocal-microscopy-list.275.s1.nabble.com/DsRed-vs-2P-tp5830859p5837482.html

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The power of the laser drops off as you go out in wavelength and in any case the
one photon excitation maximum for DsRed is approx. 550 nm so even 1000 is
not optimal. At 500 nm the excitation of DsRed is less than half of maximum.  
The problem will be even worse for mCherry. I gather there is some hope for
using an OPO to excite the red fluorescent proteins. The two photon cross-
section for DsRed is here:

http://www.biophysics.leidenuniv.nl/schmidt/Paper/CPL01_2pXFPs.pdf

They were able to get the best fluorescence at 980 but if you look at the
intensity relative to the other FPs it is weak.

Also, apparently there is some three-photon absorption by DsRed at 760 nm that
changes it from red to green, which might account for your "bleedthrough".
The immature form of DsRed is green.

Stick with the 561.