Hugo Dilhuydy wrote:

> Is dark red (~670-810nm) visible for human eye?
> If yes, is there a filter set recommended?

As previously stated, it can be seen only if it's bright--VERY BRIGHT.
Intracellularly filled neurons can be seen, but most ICC is difficult to
see and requires a CCD camera or other detector.

Note that it doesn't take an expensive CCD camera to see it.  But you
would need to remove the IR filter that's standard on most of cameras,
and you will probably need to be able to integrate perhaps 1/2 to 1 sec
exposures.

I think that Chroma Technology carries a decent filter for direct
visualization of Cy5 "by eye", but if I remember correctly it's designed
for brightness, not specificity.  I.e., you might be able to see Texas
Red through it, too.  Still, that's not bad for tissue screening.

Contact them at:

Chroma Technology
72 Cotton Mill Hill
Unit A-9, Brattleboro, VT 05301
USA
Tel: 800.824.7662 (800.8 CHROMA), 802.257.1800
Fax: 802.257.9400
http://www.chroma.com/

I have no links to this company but have gotten some good stuff from
them.

Good luck!

Martin Wessendorf
--
Martin Wessendorf, Ph.D.                        office: (612) 626 0145
Associate Professor                             lab:    (612) 624 2991
Dept. Neuroscience                      Preferred FAX:  (612) 624 8118
University of Minnesota                 Dept FAX:       (612) 626 5009
Minneapolis, MN  55455                e-mail: [log in to unmask]