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Hi Neil,
N-propyl-gallate in (30%?) glycerol is a useful antifade. Recipes can be found on the net or probably by searching this listserv.
C
Carl A. Boswell
520-954-7053
-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On Behalf Of Kilgore, Jason
Sent: Friday, November 11, 2011 12:23 PM
To: [log in to unmask]
Subject: Re: use-dependent emission of qdot **vendor response**
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I wish I could reveal what I know, but unfortunately the materials I've tried are part of internal research at Molecular Probes, and thus proprietary. Sorry for the tease.
However, I can at least reveal that such a result is seen with many antifade mounting media that contain antioxidant components. An example are mountants that contain DABCO, such as our old Slowfade mounting medium or certain "home brew" mountants.
Jason
-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On Behalf Of Neil Kad
Sent: Friday, November 11, 2011 1:08 AM
To: [log in to unmask]
Subject: Re: use-dependent emission of qdot **vendor response**
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Hi Jason,
Can you elaborate on your statement:
" we know that the presence of certain anti-oxidants and reductants can mediate the effect"
Which chemicals work well?
Best,
Neil
> Date: Thu, 10 Nov 2011 18:15:10 -0500
> From: [log in to unmask]
> Subject: Re: use-dependent emission of qdot **vendor response**
> To: [log in to unmask]
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> ** Vendor Response **
>
> Hi, Shigeo, this is a known phenomenon. Photoamplification of Qdot nanocrystals is often seen. The rate and extent of it differs depending on the mountant or buffer, differs between Qdots, and even seems to differ somewhat lot-to-lot. The exact mechanism isn't known, to my knowledge, but we know that the presence of certain anti-oxidants and reductants can mediate the effect, and undoubtedly is the result of interaction of the Qdot shell and coatings with the external environment.
>
> Qmount is a solvent-based, hardening mounting medium developed specially for Qdots and holds the intensity steady at 100%, without any significant photobleaching or photoamplification, due to proprietary components in the mountant and the fact that it cures very hard.
>
> Cheers,
>
> Jason
>
> Jason A. Kilgore
> Technical Application Scientist
> Molecular Probes Labeling and Detection Technologies Cells Systems
> Division
>
> T 1 800 955 6288 then option 5 or 541 335 0353 . F 541 335 0238
> 29851 Willow Creek Rd . Eugene . OR . 97402-9132 . United States
> www.invitrogen.com/technicalsupport
>
>
>
>
>
> -----Original Message-----
> From: Confocal Microscopy List
> [mailto:[log in to unmask]] On Behalf Of Shigeo Watanabe
> Sent: Thursday, November 10, 2011 1:04 AM
> To: [log in to unmask]
> Subject: use-dependent emission of qdot
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Dear all,
>
> My colleague measured the emission of qdot655 with the same excitation
> sequentially.
>
> He noticed that the emission of qdot was enhanced after applying the
> higher excitation light.
>
> Anybody knows about this phenomenon and mechanism?
>
> Any feedback on or off-list would be much appreciated.
>
> Sincerely,
>
> Shigeo Watanabe
> Application scienctist
> Hamamatsu Photonics KK
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