Title of Invention

A UV TRANSILLUMINATOR

Abstract

The present invention relates to an UV trans-illuminator for detecting the fluorescence of various substances in gels, solutions or surfaces comprising: - a hollow housing fitted with at least one UV-A BLB (black light blue) lamp mounted on a fixed or movable frame and having a window on the top, - a glass shell of the said BLB lamp made of blue glass for absorbing GYOR (green, yellow, orange and red) lights and transmitting UV-A radiation, - a clear and/or abraded UV-transparent sheet fitted in the window and - if desired an opaque viewer fitted with a filter and open at the bottom is placed over the window for viewing through the filter.

Full Text

Form 2 THE PATENTS ACT, 1970 COMPLETE SPECIFICATION Section 10 "A UV transilluminator for detecting the fluorescence of various substances in gels, solutions or surfaces." Dr. Bosco Maria Agnelo Henriques, an Indian national, of 1-21 Stone Castle, Mandalpeshwar, Borivili(West), Mumbai-400 103, India The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed: GRANTED ORIGINAL 473/MUM/2000 23/5/2000 FIELD OF THE INVENTION The present invention relates to UV transilluminators for detecting the fluorescence of various substances in gels, solutions or surfaces. BACKGROUND UV transilluminators are commonly employed to observe nucleic acids in gels that are stained with fluorescent dye. The most popular nucleic acid staining fluorescent dye is ethidium bromide. It gets intercalated within the double stranded regions of the nucleic acids and emits orange fluorescence when exposed to UV light. The intensity of the fluorescence is proportional to the amount of incident light, hence, the substance to be detected has to be kept as close as possible to the UV-light source. The intensity of the fluorescent light is low as compared to the intensity of incident light; fluorescence can be better visualized/detected when the incident light that stimulates the detector (the eye in the case of visual detection, photographic film or charge coupled device in the case of cameras) is minimal. In prior art transilluminators the UV-lamps are fixed in an opaque box fitted with a special UV-transparent window. This window is made of an expensive violet coloured glass that absorbs visible light and permits UV-light to pass through it. To detect/view the fluorescence, the samples placed on this window have to be observed through spectacles, cover, hood or filter made of a material that is transparent to visible light and absorbs the UV-light. In order to record the fluorescence on photographs, without having the UV-lamps sharply delineated, the UV-transparent violet glass is made partially dispersive. Of the various UV-lamps available UV-C lamps are not used as the UV-light emitted by them has a short wavelength that is mutagenic. The short wavelength UV-light also causes extensive photodimerization and photonicking of DNA. UV-A lamps emit substantial amount of violet light that would pass through both the filters (i.e., the violet filter and the viewing material filter) thereby reducing the contrast. Prior-art transilluminators therefore use UV-B emitting lamps whose UV-output peaks at 302nm. The UV-lamps are powered by chokes (wire-wound or electronic). Wheft electronic chokes are used, an option to select the intensity of the light is also provided. In summary, prior art transilluminators have one or more UV-B emitting lamps fixed in an opaque housing fitted with a violet, partially dispersive, UV-transparent glass window on the top. The lamps are connected to a source of electricity by chokes, starters and switches. A clear (visible light transparent) UV-opaque safety material is fitted between the sample and the detector to mitigate the adverse effects of UV-light on the detector. The disadvantage of such transilluminators is that the UV-B lamps emit UV-light that has a peak emission at 302nm as well as light in the visible region of the spectrum. The violet component of this visible light passes through the special violet UV-transparent glass filter lowering the contrast and making faint fluorescence difficult to detect. Also, UV-B lamps cause photo-bleaching i.e., the fluorescence fades after exposure of the material to UV-B or UV-C light. In such cases the faint fluorescence would have to be recorded as a photograph for analysis as it would not be possible to view them a second time. Further, UV-B light causes skin exposed to it, to darken and peel. The UV-B transilluminators can damage the retina of the eye. Also, the violet, partially dispersive, UV- tanspasrent glass window of the transilluminators is brittle, very expensive, gets solarized and adsorbs any ethidium bromide dye that spills on it. The adsorbed dye fluoresces, and increases the background visible light thereby decreasing sensitivity of detection. Due to the solarization the UV-transmittance decreases with time and this too lowers the sensitivity of detection. The object of the present invention is to overcome the afore-mentioned disadvantages. To achieve the said object, the present invention provides UV transilluminators for detecting the fluorescence of various substances in gels, solutions or surfaces comprising: a hollow housing fitted with at least one UV-A BLB (black light blue) lamp mounted on a fixed or movable frame and having a window on the top, a glass shell of the said BLB lamp made of blue glass for absorbing GYOR (green, yellow, orange and red) lights and transmitting UV-A radiation, a clear and/or abraded UV-transparent sheet fitted in the window and if desired an opaque viewer fitted with a filter and open at the bottom is placed over the window for viewing through the filter. Said housing and frame is made of metal, plastic, composites or wood. Said window of the hollow housing is covered with an UV transparent plastic sheet having at least 90% transmittance at 366nm. Said the UV-transparent sheet is clear. One or both of the transmitting surfaces of the said the UV-transparent sheet are abraded. The direction of the final superficial abrasional marking on said UV-transparent sheet are such that they are parallel to the length of the UV-A lamps. Said UV transparent plastic sheet is made of poly methyl methacrylate. The thickness of said UV-transparent plastic sheet ranges from one to ten mm preferably from three to six mm. Said movable frame can position the BLB UV-A lamps mounted on it just under the surface of the UV-transparent sheet or upto a distance of 120 mm from the under surface of the UV-transparent sheet. Said UV transparent sheet is translucent. An opaque viewer is disposed over the said window of the housing. Said viewer is conical or pyramidal, trapezoidal, parallelepiped or any other shape. rr" Said viewer is black. The filter is either a long pass filter or a band filter that permits fluorescent light to pass through and prevents other lights emitted by the BLB UV-A lamp from passing through. Said viewer is open at the bottom end and at the opposite top end has a holder to accommodate said filter for allowing only the fluorescent light to pass through and block the other lights emitted by the UV-A lamps. The holder for the filter is positioned between the sample to be viewed and the detector, preferably at a distance where it is not in focus by the lens of the detector that is viewing the sample. The filter is placed in the holder. An adapter is provided in the viewer for placing the camera. The shell of said BLB lamp is made of Wood's glass. The present invention will now be described with reference to the accompanying drawings: Figure 1 illustrates the UV transilluminator according to the present invention. Figure 2 illustrates the positioning of the transparent sheet in the housing Figure 3 illustrates the opaque viewer. DETAILED DESCRIPTION Referring to figure 1, the UV transilluminator comprises of an a hollow housing (1) fitted with at least one UV-A BLB (2) (black light blue) lamp mounted on a fixed or movable frame (3). As shown in figure 2, the opaque housing (1) of the transilluminator has a window (6) on the top, with a clear and/or abraded UV-transparent plastic sheet (5) fitted in the window (6). Figure 3 shows the opaque viewer (7), which has either trapezoidal or pyramidal in shape. The top narrow end (10) of the viewer has a holder for accommodating a filter (8) and opposite end (9) is open which is placed over the window (6) for viewing through the filter (8). The present invention uses one or more blue UV-A lamps. The UV-A lamps emit light that has a peak emission at 366nm. The shell of these lamps is made of Wood's glass that absorbs visible light of the green and longer wavelengths. The longer wavelength UV-A light does not cause photo-bleaching and does not cause the skin to peel. These lamps are safer to use than UV-B lamps. The use of such a UV-A lamp allows the expensive glass filter on the window of prior-art UV-transilluminator to be replaced with a clear UV-transparent plastic sheet preferably made of poly methyl methacrylate. The plastic sheet has greater than 90% transmittance at 366nm, is less expensive, does not get solarized and does not adsorb spilled dye. The clear sheet does not disperse any UV-light allowing all the transmitted light to fall on the material being analysed. This makes it possible to visually observe very faint fluorescence. Although the lamps are clearly seen through the clear window visual acuity permits analysis of the fluorescence. The thickness of the UV-transparent plastic sheet can range from one to ten mm preferably from three to six mm. The UV-transparent plastic sheet can cover the entire top surface of the UV-transilluminator or be fashioned to any desired shape or size to be fitted above the blue UV-A lamps. The violet to blue light emitted by the UV-A lamp used, lowers visual sensitivity and fogs photographic film. Hence, to view the fluorescent band, a long-pass filter (chromafilter) that absorbs the UV-light and the violet to blue light is placed between the sample to be viewed and the detector (eye or the camera). This long-pass filter allows only the fluorescent light of green and longer wavelengths to pass through. The filter is fitted in an opaque (to all wavelengths of light that the detector is sensitive to) viewing hood of trapezoidal, parallelepiped or any other shape. The filter can be fitted anywhere in between the sample to be viewed and the detector, preferably at a distance where it is not in focus by the lens of the detector that is viewing the sample. When a camera is used to record the fluorescent bands it is essential that the UV-lamps are not sharply delineated in the photographs. For this purpose a diffuser has to be placed above the UV-transparent plastic window and under the sample. The diffuser is made of the same UV-transparent plastic. The thickness of the UV-transparent diffuser can range from one to ten mm preferably from two to four mm. The UV-transparent diffuser can cover the entire top surface of the UV-transparent plastic window or be fashioned to any desired shape or size to be fitted under the sample to be photographed. The diffuser is made by grinding one or both of the transmitting surfaces of an UV-transparent plastic sheet with a fine abrasive. For this abraded plastic to act as and efficient diffuser it is important that the final superficial abrasional markings on the both surfaces are in the same direction and parallel to each other. The diffuser should also be placed above the UV-transparent plastic window with the direction of the final superficial abrasional markings in the same direction and parallel to the length of the blue UV-A lamps. The diffuser decreases the intensity of light that impinges upon the sample thereby making the fluorescence dimmer. Since the diffuser is used for photography, exposure time can be increased to capture the weaker fluorescence. In case the UV-transilluminator is being used only for photography then the clear UV-transparent window can be replaced with the UV-transparent diffuser. The blue UV-A lamps are mounted either on a fixed frame or on a frame that is vertically adjustable within the housing and can be positioned at different distances (touchmg the under surface to 120mm) from the undersurface of the UV-transparent window. The lamps are kept close to the undersurface of the clear UV-transparent window when fluorescence has to be observed visually. When a diffuser is used the lamps can be lowered so that they are not delineated in the photographs. This invention makes use of blue UV-A lamps along with low-cost UV-transparent plastic as a UV-transparent window and as a diffuser. They replace the UV-B lamps and the expensive violet, partially dispersive, UV-transparent glass. This increases the ruggedness of the apparatus and lowers its cost. This invention provides an UV-transparent window along with a separate diffuser. This allows faint fluorescence in samples to be observed and recorded. The limits of fluorescence detection have been improved by using a combination of UV-A lamp (which does not photo-bleach) and a post fluorescent chromafilter to absorb tfte light emitted by the UV-A lamp. Blue UV-A lamps can be mounted on movable or fixed frames. WORKING OF THE INVENTION The substances that have been stained with an appropriate fluorescent dye is placed on the window fitted with a clear and/or abraded UV-transparent sheet. The viewer that is fitted with the long pass filter is placed over the gel and the window. The UV-A lamps are switched on and the substances observed. We claim: A UV transilluminator for detecting the fluorescence of various substances in gels, solutions or surfaces comprising: a hollow housing fitted with at least one UV-A BLB (black light blue) lamp mounted on a fixed or movable frame and having a window on the top, a glass shell of the said BLB lamp made of blue glass for absorbing GYOR (green, yellow, orange and red) lights and transmitting UV-A radiation, a clear and/or abraded UV-transparent sheet fitted in the window and if desired an opaque viewer fitted with a filter and open at the bottom is placed over the window for viewing through the filter. 2. A UV transilluminator as claimed in claim 1 wherein said housing and frame is made of metal, plastic, composites or wood. 3. A UV transilluminator as claimed in claim 1 wherein said window of the hollow housing is covered with an UV transparent plastic sheet having at least 90% transmittance at 366nm. 4. A UV transilluminator as claimed in claim 3 wherein said the UV-transparent sheet is clear. 5. A UV transilluminator as claimed in claim 3 wherein one or both of the transmitting surfaces of the said the UV-transparent sheet are abraded. A UV transiUuminator as claimed in claim 5 wherein the direction of the final superficial abrasional marking on said UV-transparent sheet are such that they are parallel to the length of the UV-A lamps. A UV transilluminator as claimed in claim 3 wherein said UV transparent plastic sheet is made of poly methyl methacrylate. A UV transilluminator as claimed in claim 3, 4, 5, 6 or 7 wherein the thickness of said UV-transparent plastic sheet ranges from one to ten mm preferably from three to six mm. A UV transilluminator as claimed in claim 1 wherein said movable frame can position the BLB UV-A lamps mounted on it just under the surface of the UV-transparent sheet or upto a distance of 120 mm from the under surface of the UV-transparent sheet. A UV transilluminator as claimed in claim 3 wherein said UV transparent sheet is translucent. A UV transilluminator as claimed in claim 1 wherein an opaque viewer is disposed over the said window of the housing. A UV transiluminator as claimed in claim 11 wherein said viewer is conical or pyramidal, trapezoidal, paraUelepiped or any other shape. A UV transilluminator as claimed in claim 11 or 12 wherein said viewer is black. A UV transilluminator as claimed in claim 12 to 14 wherein said viewer is open at the bottom end and at the opposite top end has a holder to accommodate said filter for allowing only the fluorescent light to pass through and block the other lights emitted by the UV-A lamps. A UV transilluminator as claimed in claim 15 wherein the filter is either a long pass filter or a band filter that permits fluorescent light to pass through and prevents other lights emitted by the BLB UV-A lamp from passing through. A UV transilluminator as claimed in claim 14 and 15 wherein the holder for the filter is positioned between the sample to be viewed and the detector, preferably at a distance where it is not in focus by the lens of the detector that is viewing the sample. A UV transilluminator as claimed in claim 12 to 17 wherein said filter is placed in the holder. A UV transilluminator as claimed in claim I wherein an adapter is provided in the viewer for placing the camera. A UV transilluminator as claimed in claim 1 wherein shell of said BLB lamp is made of Wood's glass. 20. A UV transilluminator for detecting the fluorescence of various substances in gels, solutions or surfaces substantially as herein described with reference to and as illustrated by the accompanying drawings. Dated this 20th day of August, 2001 Of Anand and Anand Advocates Agents for the Applicants

Documents:

473-mum-2000-abstract(21-08-2001).doc

473-mum-2000-abstract(21-08-2001).pdf

473-mum-2000-claims(granted)-(21-08-2001).doc

473-mum-2000-claims(granted)-(21-08-2001).pdf

473-mum-2000-correspondence(23-01-2006).pdf

473-mum-2000-correspondence(ipo)-(14-10-2004).pdf

473-mum-2000-drawing(21-08-2001).pdf

473-mum-2000-form 1(23-05-2000).pdf

473-mum-2000-form 1(23-06-2000).pdf

473-mum-2000-form 19(19-05-2004).pdf

473-mum-2000-form 2(granted)-(21-08-2001).pdf

473-mum-2000-form 3(17-09-2001).pdf

473-mum-2000-form 3(27-04-2005).pdf

473-mum-2000-form 4(21-08-2001).pdf

473-mum-2000-form 5(21-08-2001).pdf

473-mum-2000-form-2(granted)-(21-08-2001).doc

473-mum-2000-others(23-05-2000).pdf

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