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Hi All,
I don't have a ton of experience here, but from what I know about phenol
red, the compound does not fluoresce on its own, but it does have a fairly
high visible light extinction coefficient. This would mean pretty high
background in fluorescence imaging unless you increase your light source
intensity. For near IR imaging and live cell, this could mean a significant
amount of thermal drift over time.
Good luck with the focus drift,
Kimberly Young

McGill University,
Montreal, Canada

On Tue, Sep 20, 2011 at 10:09 AM, Tim Feinstein <[log in to unmask]> wrote:

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>
> Hmm.  I was taught in my formative years to avoid phenol red on a
> fluorescence microscope, perhaps more from superstition than because of a
> specific problem, so I always use either OptiMEM + FBS or another medium
> without Phenol Red.  We have done up to twenty-four hour imaging of live
> cells at 37 C without any problem from the PFS focus control.
>
> cheers,
>
>
> TF
>
> Timothy Feinstein, PhD
> Postdoctoral Fellow
> Laboratory for GPCR Biology
> Dept. of Pharmacology & Chemical Biology
> University of Pittsburgh, School of Medicine
> BST W1301, 200 Lothrop St.
> Pittsburgh, PA  15261
>