FW: [Histonet] Re: mercury vs led lights **Commercial Response**

Lester Raff MD LRaff <@t> uropartners.com
Fri Sep 11 13:16:47 CDT 2009

Is anyone using LED for UroVysion?

Lester J. Raff, MD
Medical Director
UroPartners Laboratory
2225 Enterprise Dr. Suite 2511
Westchester, Il 60154
Tel 708.486.0076
Fax 708.486.0080

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Mark
Sent: Friday, September 11, 2009 12:50 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Re: mercury vs led lights **Commercial Response**

Full disclosure: My company manufactures an LED fluorescence microscope

Merced's information from the Zeiss rep is partially correct and needs
some clarification. There is a "gap" in the spectrum of available LED's
from 530 to 590 nm that would be powerful enough for fluorescence
excitation. However, there aren't many fluorophores in that range that
can't be covered by either 530 or 590 nm excitation. In fact, the
examples cited (Alexa Fluor 555, Cy3, and TRITC) work very nicely with
the 530 nm LED used in our microscope's "RFP" light cube. And to provide
a balanced reply, I should note that Zeiss offers a 530 nm LED
fluorescence module, as do other companies (e.g., Leica, CoolLED,

There are some notable exceptions to 530 or 590 nm coverage -- for
example, DsRed2 would greatly benefit from excitation in the 550-560 nm
range. Manufacturers of LED-based fluorescence instrumentation keep a
sharp eye out for new LED's that can fill in these gaps. In the
meantime, having 7 dedicated LED modules does cover a very wide range of
fluorescence applications, as noted by Eric in his message below.


-- Mark Rand

Mark Rand, Ph.D.
Product Manager and Senior Applications Scientist
Advanced Microscopy Group
Office: (425) 368-0413

> Regarding the LED light sources for fluorescent microscopy, we have
> using one of these for the past six months, and it is wonderful.  The
> lighting is bright, even, and it doesn't quench (photobleach) FITC as
> as mercury lamps do.  It is easy to align, and the expected life of
the LEDs
> is at least 10,000 hours.
> I used mercury lamps for many years, and they were fun for those of us
> like to tinker with instruments, but overall, they are a pain in the
neck to
> use every day.  About two years ago, we bought a new Nikon 50i
> which is one of the best clinical microscopes I have ever used.
> Unfortunately, the Nikon rep talked us into the EXFO metal halide
> source.  This looked good in the demo, but it has spent more time
> repaired than working in our lab.  Right now it is back at Nikon while
> try to figure out what is wrong with it.
> The LED light source that we are currently using is from a company
> Fraen.  They are an Italian company, but they have an office in the
US.  The
> unit is small, easy to install, easy to align, and gives illumination
> equivalent to a 100 watt mercury lamp.
> Merced said that there are no LEDs available for red wavelengths, but
> must just be true for Zeiss.  Fraen has LED modules that cover
virtually all
> of the fluorochromes that I have ever heard of.  They have one for red
> wavelengths that will work with TRITC, Cy3, Texas Red, Alexa Fluor
> Alexa Fluor 647, and even Cy5, which has maximum excitation at about
650 nm,
> well into the red range.
> You do need to have different LEDs for various fluorochromes, but
Fraen has
> 7 modules available, and for practical terms, about 4 of them would
> everything from DAPI to Cy5.  They are easy to interchange on the
> unit.
> I don't work for any of the companies mentioned here, nor do I receive
> compensation for saying nice things about their products.  I just like
> products.
> Eric Hoy
> ===============================================
> Eric S. Hoy, Ph.D., SI(ASCP)
> Clinical Associate Professor
> Department of Medical Laboratory Sciences
> The University of Texas Southwestern Medical Center
> Dallas, Texas
> Email: Eric.Hoy <@t> UTSouthwestern.edu
> ===============================================
> Message: 1
> Date: Wed, 09 Sep 2009 13:43:45 -0400
> From: Merced M Leiker <leiker <@t> buffalo.edu>
> Subject: Re: [Histonet] mercury vs led lights
> To: Nejat Yilmaz <nyilmaz <@t> mersin.edu.tr>,
> histonet <@t> lists.utsouthwestern.edu
> Message-ID: <6276F2A000238523BC2681F5 <@t>
> Content-Type: text/plain; charset=us-ascii; format=flowed
> I forgot to mention. An LED can be made to excite FITC, DAPI, and Cy5
> (far-red) fluorophores, but they cannot make them in the red (Alexa
> 555, Cy3, TRITC, etc.) This is per our Zeiss rep. So on our inverted
> microscope we have LEDs and we also have a mercury lamp to cover the
> range. The Zeiss switches nicely and very smoothly between the light
> sources during viewing and image acquisition.
> Sorry for the highly untechnical description, but that is all I know
> it.  :-)

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