http://confocal-microscopy-list.275.s1.nabble.com/Inventor-of-fluorescence-Ploemopak-in-running-for-Nobel-Prize-website-on-his-early-technology-tp7580208p7580249.html
I think the Nobel is for experimental work, not just technology so I'm not sure the filter cube is a candidate. While we are talking about fluorescence microscopy what about the development and application of live cell real time fluorescence imaging/microscpectrofluorimetry? That developed some time later but I don't know whose work predated my own work on video rate Ca imaging … Any ideas/references ?
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> I have been thinking about this for over a week now off and on, and I think I can put down in writing the main technical reasons why Ploem's contribution IS worthy of a Nobel prize (recognizing of course that I might be a bit biased towards seeing another prize being awarded to imaging science and technology, of course).
>
> 1. Older transmitted (diascopic) fluorescence illumination employed a condenser lens to focus illumination light in order to excite fluorochromes / fluorescent probes embedded in a microscopic sample. This required that the condenser lens be well aligned to the objective lens (Kohler illumination). Many of the early diascopic fluorescence microscopes also employed a darkfield type of illumination to reduce the background light, and in doing so necessitated the application of a high NA oil-immersion condenser lens which further complicated the optical alignment. The switch to incident (episcopic) fluorescence illumination allowed the objective lens to also take on the role of the condenser lens (concentrating/focusing the illumination light into the centre of the field of view and onto the correct focal plane), and since the excitation and emission light path traversed the same lens, the optical required alignment was achieved automatically.
>
> 2. Related to point 1, with the objective now playing the role of excitation light concentrator and emission light collector, one could design and use high NA immersion objective lenses with better light throughput capabilities.
>
> 3. With incident/episcopic illumination, the amount of image-contaminating background illumination light is greatly reduced since most of the illumination light transmits through the sample and never re-enters into the detection light path. As stated in the Chroma Handbook of Optical Filters for Fluorescence Microscopy, "... By illuminating with incident light [one needs only to] filter out excitation light back-scattering from the specimen or reflecting from glass surfaces . The use of high-quality oil-immersion objectives (made with materials that have minimal autofluorescence and using low-fluorescence oil) eliminates surface reflections, which can reduce the level of back-scattered light to as little as 1% of the incident light." The quality of barrier filters employed at the time in early diascopic fluorescence microscopes were such that they could not achieve the same level of illumination light rejection in the final image.
>
> 4. Early diascopic fluorescence microscopes used UV light to excite fluorochromes/fluorescent probes embedded in a microscopic sample. This design lessened the demands of the barrier filters (UV light is absorbed by most glasses), but it also had the disadvantage that the UV light could elicit autofluorescence in the sample and optics of the microscope (which leads to image background light again). In addition, the exciting UV light had to traverse the sample and mounting slide, thus being absorbed and scattered through thicker tissues and leading to weak fluorescent image signals in those cases. As far as I can tell, Ploem (and perhaps a few other researchers - still not clear to me because I don't have access to the original research articles) realized that common fluorescent dyes like FITC could be efficiently excited with visible BLUE wavelengths and TRITC could be efficiently excited with visible GREEN wavelengths, thereby doing away with the need for pure UV excitation.
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> 5. Bearing points 1-4 in mind, the implementation of the filter cube block - the very heart of the epifluorescence microscope design - now makes clear sense. The introduction of dichroic beamsplitters by Brumberg, and their subsequent commercialization/development by Ploem further improved the filtering of excitation illumination light from the fluorescence emission light and also created a convenient method of introducing incident light onto the sample.
>
> It is often stated that the fluorescent signal that ultimately forms the desired image of the sample is several orders of magnitude weaker than the excitation light that is used to generate it. That is to say, when we form an fluorescence image, much effort has gone into filtering out and removing the illumination light as much as possible to create a dark/black background on which the fluorescence signal overlays. That's the name of the game in fluorescence imaging - filter out the unwanted signal as much as you can. It's not just the dichroic mirror and barrier filters doing this. It's the incident light / episcopic microscope design and the application of optimized excitation wavelengths for the fluorescent probes that also play a big role in this filtering process - a fact that I (and I imagine most of us) take for granted every time we snap a fluorescence image. It's a rather simple change to the microscope that Ploem and his colleagues of the time made, but modern fluorescence imaging (with confocal, TIRF, and super-resolution methods) would not be what it is today with such widespread use in research, medicine, and industry without that fundamental change.
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> And who could count the number of discoveries and advancements that have come about with the fluorescence microscope since that time? It is a true workhorse in biology and worthy of a Nobel in my opinion then. I wish Dr. Ploem all the luck with the decision!
>
> John Oreopoulos
> Staff Scientist
> Spectral Applied Research
> Richmond Hill, Ontario
> Canada
> www.spectral.ca
>
>
> On 2013-04-21, at 11:13 PM, Guy Cox wrote:
>
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>> There is a historical essay on all this by Ploem and Walter, published by Leica in their series Scientific and Technical Information, Edition CDR 5, pp. 1-16,12/2001. "Multi-wavelength epi-illumination in fluorescence microscopy"
>>
http://www.leica-microsystems.com/fileadmin/downloads/Other/Publications/Leica_STI_CDR5_ploem_walter_en.pdf.
>>
>> Brumberg is given due credit. Of course the Iron Curtain meant that Ploem was not originally aware of that work, and the Brumberg and Krylova 1953 paper is in Russian, so may not mean much to most of us even if it can be found. (Suspect you'd have to use Cyrillic Google to find since English Google doesn't).
>>
>> Guy
>>
>> -----Original Message-----
>> From: Confocal Microscopy List [mailto:
[hidden email]] On Behalf Of Mark Cannell
>> Sent: Monday, 22 April 2013 1:16 AM
>> To:
[hidden email]
>> Subject: Re: Inventor of fluorescence Ploemopak in running for Nobel Prize + website on his early technology
>>
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>> Hi John
>>
>> Here is a centenary review of his work....
>>
http://link.springer.com/content/pdf/10.1134%2FS1062359007020161.pdf>> Here is a list of papers that are available for a fee..
>>
>>
http://pubget.com/search?from=18912654&page=1&q=author%3A%22E+M+EM+BRUMBERG%22>>
>> perhaps you can get copies via your library?
>>
>> Cheers Mark
>>
>> On 20/04/2013, at 5:08 PM, John Oreopoulos <
[hidden email]> wrote:
>>
>>> *****
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>>> Mark,
>>>
>>> Your last posting peaked my curiosity, so I decided to look a bit into this. The best I could come up with was a document by Barry Masters on the history of fluorescence microscopy:
>>>
>>>
http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=0CEMQFjAAOAo&url=http%3A%2F%2Fwww.fen.bilkent.edu.tr%2F~physics%2Fnews%2Fmasters%2FELS_Hist_Fl_Micro.pdf&ei=4rlyUe2hLtGp4APHr4GwCg&usg=AFQjCNEW1u-TzRGu5wml8GZ26qGUN9iW3A&sig2=HnzzQ9CvfTkEvfJWVcfCeg&bvm=bv.45512109,d.dmg&cad=rja>>>
>>> Both Brumberg and Ploem are mentioned in the context of some very important developments of epi-fluorescence microscopy. By chance, does anyone have a copy of the papers cited involving these authors? (Brumberg 1959, and Ploem 1967).
>>>
>>> John Oreopoulos
>>> Staff Scientist
>>> Spectral Applied Research
>>> Richmond Hill, Ontario
>>> Canada
>>> www.spectral.ca
>>>
>>>
>>> On 2013-04-19, at 5:44 PM, Mark Cannell wrote:
>>>
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>>>> I hope the pioneering work in 1948 of Evengenii Mikhailovich Brumberg is mentioned/considered in this context.
>>>>
>>>> Cheers
>>>>
>>>>
[hidden email]
>>
>> Mark B. Cannell Ph.D. FRSNZ
>> Professor of Cardiac Cell Biology
>> School of Physiology & Pharmacology
>> Medical Sciences Building
>> University of Bristol
>> Bristol
>> BS8 1TD UK
>>
>>
[hidden email]
Mark B. Cannell Ph.D. FRSNZ