Typically, what you image is Trp fluorescence by exciting at around 280 nm and observing at around 350 nm. Standard silicon based detectors do fine at the detection wavelength, although, as you can imagine, increased sensitivity in the UV means increase in the price of the detector. If your excitation and emission light paths do not overlap, you also can get by with standard glass (crown, flint, etc.) optics since they do allow some of the 350-nm light to get through. Therefore, yes, it is possible to build an inexpensive UV imager based on inexpensive excitation light source (Douglas Instruments offers a pen light), and standard lab microscope. Of course, for increased sensitivity and contrast you need a very good light source, optics made of quartz and calcium fluoride that let almost all the UV light through, highly discriminating filters and a sensitive detector.
V. Nagarajan JANSi http://janscientific.com On Thu, Sep 15, 2011 at 7:07 PM, Edward A. Berry <ber...@upstate.edu> wrote: > A "real" UV microscope requires quartz optics, right? > Probably conventional microscopes use glass. > And you can't see 280 nm (and its not good for your eyes) > so you need some kind of phosphor screen to view the image? > > > Bosch, Juergen wrote: > >> I'm replying here to myself :-) >> >> So in an off-board discussion it turns out that the "microscope" in >> question was a special >> emitted light and not a UV microscope. So real UV microscopes might be >> better for the >> purpose of detecting real crystals. >> >> Sorry for the confusion - had too much sun today :-) >> >> Jürgen >> >> On Sep 15, 2011, at 4:19 PM, Jürgen Bosch wrote: >> >> I once tested such a commercial system in Seattle about 4 years ago. It >>> did not impress >>> me. In particular the discrimination between salt and protein did not >>> work for about 10 >>> different proteins from which we already had collected data. sure those >>> were small >>> between 10 and 100 micrometer. Excuse was to few tryptophans >>> So in theory it is nice but a cheaper variant might be to add Gfp to your >>> protein and >>> screen for something green. >>> Jürgen >>> >>> ...................... >>> Jürgen Bosch >>> Johns Hopkins Bloomberg School of Public Health >>> Department of Biochemistry & Molecular Biology >>> Johns Hopkins Malaria Research Institute >>> 615 North Wolfe Street, W8708 >>> Baltimore, MD 21205 >>> Phone: +1-410-614-4742 >>> Lab: +1-410-614-4894 >>> Fax: +1-410-955-3655 >>> http://web.mac.com/bosch_lab/ >>> >>> On Sep 15, 2011, at 16:03, Frank von Delft <frank.vonde...@sgc.ox.ac.uk> >>> wrote: >>> >>> A while ago I was trying to be cheap, so we played around with it quite >>>> a bit in the lab. After rediscovering some of the basics of >>>> signal-to-noise and microscope transmission efficiency and that sort of >>>> rot, I realised that the commercial systems may not be all that >>>> ridiculously overpriced after all. Not if one wants to be able to say >>>> something useful about really really small crystals -- the only ones >>>> that really matter in the grand scheme of things (big ones are quick to >>>> test; little ones must first be optimized = money+time). >>>> >>>> But maybe I was just being incompetent. Happens. >>>> phx. >>>> >>>> >>>> >>>> >>>> On 15/09/2011 20:50, Andrew Purkiss-Trew wrote: >>>> >>>>> Quoting "Harman, >>>>> Christine"<Christine.Harman@**FDA.HHS.GOV<christine.har...@fda.hhs.gov> >>>>> >: >>>>> >>>>> Hi All, >>>>>> I was curious if any of you have tried or even know if it is >>>>>> possible to adapt a stereoscope (in my case an Olympus SZX10 model) >>>>>> so as to view protein crystals with UV illumination. Basically, I >>>>>> want a cheap manual version of what a Rock UV Imager does. I know >>>>>> this is probably a crazy dream. However, I would greatly appreciate >>>>>> any comments, advice or experience any of you may have. >>>>>> >>>>>> Molecular Dimension do such an adaptor which fits to existing >>>>> microscopes. >>>>> >>>>> See >>>>> <http://www.**moleculardimensions.com/**shopdisplayproducts.asp?id=** >>>>> 121&cat=X%2DtaLight%3Csup%3E%**99%3C%2Fsup%3E+100+%2D+UV+for+** >>>>> Microscope+<http://www.moleculardimensions.com/shopdisplayproducts.asp?id=121&cat=X%2DtaLight%3Csup%3E%99%3C%2Fsup%3E+100+%2D+UV+for+Microscope+> >>>>> > >>>>> >>>>> >>>>> ------------------------------**------------------------------**---- >>>>> This message was sent using IMP, the Internet Messaging Program. >>>>> >>>> >> ...................... >> Jürgen Bosch >> Johns Hopkins University >> Bloomberg School of Public Health >> Department of Biochemistry & Molecular Biology >> Johns Hopkins Malaria Research Institute >> 615 North Wolfe Street, W8708 >> Baltimore, MD 21205 >> Office: +1-410-614-4742 >> Lab: +1-410-614-4894 >> Fax: +1-410-955-2926 >> http://web.mac.com/bosch_lab/ >> >> >> >> >> >>
