Abstract:
Disclosed in this specification is a high capacity compact gel documentation system for documenting different types of electrophoresis gels or other translucent objects using ultraviolet light. The system includes a base with a scanning surface having a transparent bottom surface. A light source is connected to a conveying mechanism, disposed below the transparent bottom surface, to move the light source over the length of the transparent bottom surface. An image capture device receives a reflected image and provides it to a microprocessor. Moreover, separate interchangeable filters allow for documentation of UV and white light gel captures, alleviating the need for separate transilluminators and hoods with filters and cameras.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of U.S. provisional patent application Ser. No. 61/596,162, filed Feb. 7, 2012, which application is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates, in one embodiment, to gel documentation systems. 
       BACKGROUND 
       [0003]    Gel documentation systems are used to record the image of an electrophoresis gel. In a conventional gel documentation system an electrophoresis gel is placed on an ultraviolet (UV) transilluminator. The UV transilluminator is often disposed proximate a relatively large hood to potentially entrapping harmful vapors that may be emitted from the gel and allow capture of images through creating a dark environment. Disposed above the gel is a light filter above which is placed digital camera. The transparent gel is illuminated with the transilluminator and an image of the illuminated gel is recorded with the digital camera. The UV transilluminator is used for ethidium bromide stained gels. Other gels require potentially a separate transilluninator, a separate hood with another filter and possibly a second camera. 
         [0004]    Unfortunately, conventional gel documentation systems are expensive, typically costing over $30,000 each for a large, high-end system with more functionally and approximately $5,000 for a low end system with very limited capacity. Due to this expense, a given department often has only one such system. Therefore, an improved gel documentation system is desired. 
       SUMMARY OF THE INVENTION 
       [0005]    Disclosed in this specification is a high capacity compact gel documentation system for documenting different types of electrophoresis gels or other translucent objects using ultraviolet light. The system includes a base with a scanning surface having a transparent bottom surface. A light source is connected to a conveying mechanism, disposed below the transparent bottom surface, to move the light source over the length of the transparent bottom surface. An image capture device receives a reflected image and provides it to a microprocessor. Moreover, separate interchangeable filters allow for documentation of UV and white light gel captures, alleviating the need for separate transilluminators and hoods with filters and cameras. 
         [0006]    In one exemplary embodiment, a gel documentation system for documenting an electrophoresis gel is disclosed. The gel documentation system has an electrophoresis gel with a base that provides a transparent bottom surface. A light source is operatively connected to a conveying mechanism to move the light source over the length of the transparent bottom surface. The light source emits a narrowband wavelength of ultraviolet light. 
         [0007]    In another exemplary embodiment, a gel documentation system for documenting an electrophoresis gel is disclosed. The gel documentation system has a cover and a base that provides a transparent bottom surface within a scanning recess. The scanning recess is disposed below a top surface of the base by a predetermined depth sufficient to contain an electrophoresis gel without the electrophoresis gel contacting the cover when the cover is disposed on the top surface of the base. A light source is operatively connected to a conveying mechanism to move the light source over the length of the transparent bottom surface. The light source emits a narrowband wavelength selected from the group consisting of 254 nm, 312 nm, 365 nm and combinations thereof 
         [0008]    In another exemplary embodiment, a method for documenting an electrophoresis gel is disclosed. The method includes the steps of disposing an electrophoresis gel within a scanning recess of a gel documentation system. The system includes a base with the scanning recess that provides a transparent bottom surface. The scanning recess is disposed below a top surface of the base by a predetermined depth sufficient to contain an electrophoresis gel without the electrophoresis gel contacting the cover when a cover is disposed on the top surface of the base. A light source is operatively connected to a conveying mechanism to move the light source over the length of the transparent bottom surface. The light source emits a narrowband wavelength selected from the group consisting of 254 nm, 312 nm, 365 nm and combinations thereof. The method further includes the steps of actuating the conveying mechanism to move the light source over at least a portion of the length of the transparent bottom surface and emitting light from the light source as the conveying mechanism is actuated. The method includes the step of capturing an image of the electrophoresis gel and digitizing the image. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention is disclosed with reference to the accompanying drawings, wherein: 
           [0010]      FIG. 1  is a perspective view of an exemplary gel documentation system; 
           [0011]      FIG. 2A  is a cross sectional side view of an exemplary base; 
           [0012]      FIG. 2B  is a top view of an exemplary base; 
           [0013]      FIG. 3  is a top view of an exemplary cover; 
           [0014]      FIG. 4  is a flow diagram depicting an exemplary method for documenting an electrophoresis gel; and 
           [0015]      FIG. 5  is a block diagram of select components of a gel documentation system. 
       
    
    
       [0016]    Corresponding reference characters indicate corresponding parts throughout the several views. The examples set out herein illustrate several embodiments of the invention but should not be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION 
       [0017]      FIG. 1  is a perspective view of an exemplary gel documentation system  100  for scanning an electrophoresis gel  102 . System  100  comprises a base  200  with a scanning surface  202 . The scanning surface  202  has a transparent bottom surface  203  (see  FIG. 2A ) with a length  206  and a width  208  (see  FIG. 2B ). The transparent bottom surface  203  is permeable to UV light and, in some embodiments, white light. The system  100  further comprises an exemplary cover  300  that is connected to an edge of the base  200  by a hinge  302 . The base  200  may share many of the components of conventional flatbed scanners but the base  200  differs from such scanners as taught in the present specification. Examples of conventional flatbed scanners include U.S. Pat. Nos. 5,816,969 and 6,271,939. The content of each of these patents is hereby incorporated by reference into this specification. A more detailed depiction of the base  200  is shown in  FIG. 2A  and  FIG. 2B . 
         [0018]      FIG. 2A  is a cross sectional side view of the exemplary base  200 .  FIG. 2B  is a top view of the exemplary base  200 . In the exemplary embodiment, the scanning surface is a scanning recess  205  that provides a cavity to contain gel  102 . The scanning recess  205  is disposed below a top surface  200   a  (see  FIG. 1 ) of the base  200  by a predetermined depth  204 . The depth  204  is selected to be greater than a height of the gel  102  thereby ensuring that, when the cover  300  is closed atop the base  200 , the gel  102  is not touched by the cover  300 . In another embodiment, not shown, the cover  300  includes a raised cavity that provides a recess to contain gel  102  to ensure the cover  300  does not touch the gel  102 . 
         [0019]    In one embodiment, the scanning recess  205  provides a liquid-tight tray that contains any residual moisture that may be excreted by the gel  102 . In one embodiment, scanning recess  205  is a removable tray that rests on a ledge  206   b  proximate the top surface  200   a  of base  200 . After use, the user need only lift the removable tray upwards to remove it from the base  200 . The gel and any potentially hazardous chemicals associated with the gel may then be safely disposed in a conscientious mariner. In one embodiment, the transparent bottom surface  203  and vertical sidewalls of the removable tray are discrete components joined by a liquid-tight seal. In another embodiment the transparent bottom surface  203  and vertical sidewalls are monolithic. In one such embodiment, a gentle slope is present between the transparent bottom surface  203  and vertical sidewalls to avoid the presence of a sharp corner that may prove difficult to clean. 
         [0020]    The exemplary base  200  further comprises a slot  211  in a vertical edge  200   b  with a sliding filter  210  disposed therein. Sliding filter  210  is configured to filter light that passes therethrough. The slot  211  is positioned below the transparent bottom surface  203  of the scanning recess  205  and above a light source  218 . The sliding filter  210  has a length  213  that is at least as long as the width  208  of the transparent bottom surface  203 . The sliding filter  210  has a width  212  that is selected to be wider than the width of gel  102 . In one embodiment, the sliding filter  210  has a length  213  and a width  212  sufficient to correspond to a portion of the area of the transparent bottom surface  203 . In another embodiment, the sliding filter  210  has a length  213  and a width  212  sufficient to substantially correspond to the area of the transparent bottom surface  203 . In the embodiment depicted, the slot  211  is disposed in a first edge such that the length of the sliding filter  210  traverses the width  208  of the transparent bottom surface  203 . Because the sliding filter  210  is removable from the slot  211 , different filters  210  may be interchangeably inserted into the slot  211 . 
         [0021]    The light source  218  is operatively connected to a conveying mechanism  220  that is configured to move the light source  218  over at least a portion of the length  212  of the scanning recess  205 . The conveying mechanism  220  may include a means for driving the light source  218  past the object being documented. Examples of suitable means for driving include a stepper motor. In one embodiment, the light source  218  is configured to emit ultraviolet (UV) light and white light. In another embodiment, the light source  218  is configured to emit only white light. In another embodiment, the light source  218  is configured to emit only ultraviolet light. In yet another embodiment, the light source  218  is configured to emit only ultraviolet light at a predetermined wavelength selected from 254 nm, 312 nm, 365 nm or combinations thereof. In some embodiments, the wavelength of light is controlled such that only a narrow bandwidth of less than about 10 nm is emitted. The base  200  also comprises an image capture device  222  which, in the depicted embodiment, is disposed on the conveying mechanism to receive a reflected image of the gel  102  when the gel  102  is illuminated by light source  218 . Examples of suitable image capture devices  222  include an array of photodiodes including a charge-coupled device (CCD). The image capture device  222  may further include an analog-to-digital converter. 
         [0022]    The base  200  may also include a power input  216  which may connect to an external power supply. In another embodiment, the base  200  includes a battery, such as a backup battery. One or more data ports  214  may also be provided. The data ports  214  permit the system  100  to be in wired or wireless communication with external devices (e.g. printers, computers, data storage devices including hard drives, flash drives, and the like). In one embodiment, at least one of the data ports  214  is a Universal Serial Bus (USB) data port. In this fashion digital images of the gel  102  may be printed and/or saved to an external device for further manipulation. In one embodiment, the base  200  includes a built-in printer. 
         [0023]      FIG. 3  is a top view of the exemplary cover  300 . The cover  300  comprises a display  304  that is operatively connected to a microprocessor to provide a user interface. In one embodiment, display  304  is a touch screen display. Display  304  may be configured to provide a preview image of the gel  102  as the documentation method occurs. In this fashion a user is permitted to rapidly see the results of the current documentation attempt and, if desired, adjust the system in an attempt to obtain a better image. Display  304 , in certain embodiments, provides a mechanism for permitting the user to navigate through software menus to select certain features. Examples of such features include copying of digital files to an attached storage device, printing to an attached or integral printer, and the like. 
         [0024]      FIG. 4  is a flow diagram depicting an exemplary method  400  for documenting an electrophoresis gel. The method will be further described with reference to  FIG. 5  which is a block diagram of select components of a gel documentation system. As shown in  FIG. 5  a microprocessor  500  controls various components of the gel documentation system including the light source  218  and the image capture device  222 . The microprocessor  500  also controls motor  502  which, in one embodiment, is a stepper motor of the conveying mechanism  220 . The microprocessor is also in communication with a display driver  504  which controls display  304 . Devices  506 , such as internal memory devices or external devices, are also in communication with microprocessor  500 . The method  400  begins with a step  402 . 
         [0025]    Referring again to  FIG. 4 , in step  402  a gel  102  is disposed in the scanning recess  205  of the gel documentation system  100 . The cover  300  may be closed to provide a light controlled (e.g. dark) environment within the scanning recess  205 . The light-controlled environment also contains ultraviolet light from the light source  218  which provides a safety benefit to the user. In step  404  the conveying mechanism  220  is actuated. For example, the display  304  may include a “scan” graphic that performs the actuation. Upon actuation, the microprocessor  500  controls the motor  502  of the conveying mechanism  220 . This, in turn, causes the light source  218  and the image capture device  222  to traverse past the object being scanned. During movement, the microprocessor  500  activates the light source  218  and receives data from the image capture device  222 . When the conveying mechanism  220  reaches a predetermined position, the light source  218  and the image capture device  222  are deactivated and the conveying mechanism  220  is returned to its original position. The data received from the image capture device is then processed into a digital image. For example, current and/or voltage data from an array of photodiodes in the image capture device  222  is sent to an analog-to-digital converter. The resulting digital signals are representative of the captured image. The digital signals are then sent, by the microprocessor  500 , to a display driver  504 . The display driver  504  applies digital signals to the display  304  to generate an image representative of the captured image. 
         [0026]    In step  406 , light is emitted from the light source  218  as the conveying mechanism  220  moves it across the length  206  of the scanning recess  205 . The reflected light is received by the image capture device  222  in step  408 . The captured image is received in sequential slices as the conveying mechanism  220  moves. Each slice is provided to a microprocessor within the base  200  and the microprocessor compiles the slices into a compiled digital image of the gel  102  in step  410 . The compiled image is displayed to the user on display  304  and the user then determines whether or not the image should be saved to a storage medium. 
         [0027]    In some embodiments, the scanning recess  205  is then removed from the base in step  412 . In step  414  the gel  102  is disposed and the scanning recess  205  is cleaned. In step  416  the scanning recess  205  is replaced into the base  200  for subsequent use. 
         [0028]    In one embodiment, the system  100  includes a means to select the wavelength of light that is emitted from the light source  218 . In one embodiment, the display  304  is a touch screen display and the means to select the wavelength is the touch screen display. In another embodiment, the means to select the wavelength is one or more switches on the base. In one embodiment, the user may select, for example, wavelengths of 324 nm, 312 nm, 365 nm, and any combination thereof, or white light. 
         [0029]    The conveying mechanism  220  provides a mechanism to control the exposure time of the gel  102 . Convention gel documentation systems can only control exposure time by leaving the camera open for a predetermined period of time. With conventional systems, this necessarily requires all section of the gel be imaged with equal light intensity. In contrast, the conveying mechanism  220  can be adjusted to control the exposure time of the gel  102 . For example, in one embodiment, an initial digital image is compiled at a relatively fast conveying speed. The user can see a preview image of the gel  102  at this fast speed in display  302 . After the preview image is deemed satisfactory, a subsequent image can be acquired at slower conveying speed with a longer exposure time. 
         [0030]    The gel documentation system described herein is substantially more compact and inexpensive than previous systems to provide a new system that requires minimal training and is easy to use. Although the exemplary embodiments described herein have focused on electrophoresis gels the system is also applicable to other translucent objects. 
         [0031]    While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof to adapt to particular situations without departing from the scope of the disclosure. Therefore, it is intended that the claims not be limited to the particular embodiments disclosed, but that the claims will include all embodiments falling within the scope and spirit of the appended claims.