You can get extended wavelength PMTs, but your system may or may not
include them.  Many of Hamamatsu's (major PMT manufacturer) PMTs are
good out to 900nm or so which should hopefully work.  The one problem
with these longer IR dyes is that your detection system needs to be
capable of picking up the NIR signal from them.  I was assuming the
questioner had already taken this into account but I suppose it should
be brought up given that off-the-shelf systems won't have the
necessary detectors or filters.

Some Hamamatsu PMTs out to 900nm:
http://jp.hamamatsu.com/products/sensor-etd/pd002/pd395/index_en.html
(scroll down to see the spectral response curves)

Craig


On Wed, Jul 15, 2009 at 4:03 PM, Andreas Bruckbauer<[log in to unmask]> wrote:
>>If you want to use single photon you can just tune your Ti:Saph to 750 and
>> you should be good to go
>
> You would need a suitable dichroic for direct excitation at 750 nm, the
> multiphoton dichroics usually reflect everything above 680 or so, your
> fluorescence signal would not reach the detector. Furthermore the normal
> photomultiplier detectors are almost blind in the far red, laser power would
> need to be reduced quite a lot... Has anyone tried direct 1P excitation of
> these dyes?
>
> Andreas
>
>
> -----Original Message-----
> From: Craig Brideau <[log in to unmask]>
> To: [log in to unmask]
> Sent: Wed, 15 Jul 2009 22:37
> Subject: Re: VisEn Prosense 750 on multiphoton?
>
> For multiphoton (in this case 2 photon) won't you need a very long
>
> wavelength?  Probably >1200nm?  Ti:Saphs don't go beyond 1100nm so you
>
> won't be able to use multiphoton to stimulate it unless you have a
>
> Cr:Forsterite laser lying around or an OPA/OPO system strapped to your
>
> Ti:Saph.  If you want to use single photon you can just tune your
>
> Ti:Saph to 750 and you should be good to go.
>
>
>
> Craig
>
>
>
>
>
> On Wed, Jul 15, 2009 at 1:30 PM, Gastinger, Matthew (NIH/NIAID)
>
> [C]<[log in to unmask]> wrote:
>
>> We have someone who wants to use ProSense 750 (a protease activatable
>
>> fluorescent in vivo imaging agent) from VisEN.  He wants to image in vivo
>
>> using confocal microscopy.  The alternative is ProSense 680, but 750 is
>
>> likely to produce less autofluorescence.  ProSense 680 will likely work
>> with
>
>> 633 laser or whitelight laser at 670nm.
>
>>
>
>>
>
>>
>
>> Has anyone imaged VisEN ProSense 750 using multiphoton confocal
>> microscopy?
>
>> If so, what are equipment specs generating images.
>
>>
>
>>
>
>>
>
>> Thanks.
>
>
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