An Inexpensive Gel Documentation System Tony Schountz, PhD School of Biological Sciences University of Northern Colorado tony.schountz@unco.edu http://www.unco.edu/schountz/gel/ Revision 3.2 16 Oct 2006
Commercially-available gel documentation systems cost US$2,000 or more, but usually have software for sophisticated gel analysis. This document describes the assembly of a gel documentation system (image capture) for about US$250. It requires basic skills in power tool use to build a light box for a commercially-available digital camera, the Canon PowerShot A520.
The idea for this system was adapted from one used by the Hirsh Lab http://www.virginia.edu/biology/fac/hirs h_gel/gel/ Although this system is working for me, I offer no guarantees that it will work for you!
Camera Equipment (Can be purchased from B&H Photo*) Canon PowerShot A520 (B&H #CAPSA520) - $170 LA-DC52F 52 mm filter adapter for A520 (B&H #CALADC52F) - $18 52 mm UV filter (B&H #BWUV52) - $20 52 mm infracolor 099 orange filter (B&H #BW09952) - $20 1/4 Tripod screw (B&H #LI861568 or Home Depot) - $4.50 ACK-800 AC Adapter Kit (B&H #CAACK800) - $40 (optional - eliminates the need for camera batteries) B&H Photo http://www.bhphoto.com/ *I have no financial interest in B&H Photo
Canon PowerShot A520 Needed items included with the camera PowerShot A520 Body (4 megapixels) MultiMediaCard memory card (included with most cameras)* 2 AA Alkaline Batteries Canon Digital Camera Solution CD- ROM USB Interface Cable *There is no need to purchase a larger memory card because the images are stored on your hard drive, not the camera s memory card
Camera Note Although this document discusses the use of the PowerShot A520, other Canon cameras should work, so long as there is a filter adapter for the camera. So far, we have used three Canon cameras with success, the PowerShots A520, A95 and A70. These are no longer in production, but Canon offers others with similar prices and features. For additional information, see Canon s web site: http://www.usa.canon.com/html/canonindex.html
Software Canon Digital Camera Solution Disk (included with the Canon camera) ImageJ - http://rsb.info.nih.gov/ij/ Gel-converter.class plugin for ImageJ, available at the Hirsh lab web site Optional: iphoto 5 (Mac users only)
Hardware USB-equipped Mac (OS X) or Windows PC Transilluminator Five sided box (1/2 width boards) with 2.25 hole in the top to accommodate the camera filter adapter 1/2 Weather stripping L-bracket with 1/4 hole for tripod screw (e.g., Home Depot) 1/4 nut for the tripod screw (to secure it to the L-bracket) Handles for the sides of the box #6 x 3/4 screws for holding the box together; #5 x 5/8 screws for attaching the L-bracket
Tools Table, circular, or jig saw Straight edge for cutting guide Drill and bits Screw driver Optional: Router with flush-trim bit Optional: Random orbit sander/220+ paper
Box Construction 1/2 Medium-density fiberboard (MDF; Home Depot, Here s how I made my camera box 1 : Lowes, etc.). 10 d x 11 w x 10 h. I cut four 10 x10 boards for the sides and a 10 x11 top. You ll need to customdesign a box to fit your transilluminator. The height should be enough so that the camera can see all of the glass on the transilluminator. I used a router with a flush-trim bit to get nice smooth edges. Held together with wood glue (probably not necessary) and countersunk #6 x 3/4 wood screws. Pre-drill the holes for the screws. Use a hand-held screwdriver, and not a powered screwdriver, to tighten screws in MDF. Do not over-tighten! 2.25 hole for filter adapter was cut with a hole saw (about $11 from Home Depot) for power drill. Lightly sand the outside surfaces. Prime, then spraypaint flat black inside and outside. This is important because it eliminates reflections and flare inside the box. Handles attached with screws only. 1/2 weather stripping on bottom edges to protect the transilluminator glass. L-bracket screw hole drilled out to 1/4 to accommodate tripod screw. Important: Mount the L- bracket to the camera before marking the drill holes for mounting the bracket to the box. This is necessary because the filter adapter protrudes into the box. Use 1 Note: If you don t have access to a power saw or are uncomfortable using one, most home centers (such as Home Depot or Lowes) will custom cut MDF to size for a small price. Usually, the first two cuts are free, the rest are about $1 each. The accuracy of these cuts are adequate
System Assembly Attach filter/lens adapter to camera Attach UV filter to adapter Attach orange filter to UV filter Thread tripod screw through L-bracket, then onto the camera. Visually align the camera so that it is perpendicular to the transilluminator glass. Position the box on the transilluminator Note the USB and power adapter cables are plugged into the camera. The Maxell AC 3000 power adapter (Circuit City), pictured above, is plugged into the outlet (red box) and connected to a PowerShot A70. The PowerShot A520 has a 3.2 V requirement. The AC 3000 has a voltage setting (3.3 V) close to the A520 s requirement. The Canon ACK-800 adapter is about $7 more than the AC 3000. Other Canon cameras have different voltage requirements, so exercise caution when setting the voltage on the
Turn the camera on; CameraWindow should launch System Setup Install the Canon software Install the ImageJ software Install the gel_converter.class plugin into ImageJ s plugin folder Connect the camera to a USB port Make sure the camera is set to Playback Mode using the Mode Switch If you re using Mac OS X, open the application Image Capture. In the Preferences, set the camera connection option to open the CameraWindow application found inside the Canon directory. Quit Image Capture. From now on, anytime the camera is turned on, CameraWindow should automatically launch.
CameraWindow Canon software utility that controls the camera from the computer After it opens, click on Remote Shooting Click on the icon for Starts Remote Shooting You ll be prompted for where the image files are to be saved.
Remote Shooting The RemoteCapture Task application is used for capturing gel images Size and Resolution Rotation Setting You should see a live video of what s on the gel box Adjust the gel s position so that it s roughly centered in the video window Zoom using the zoom slider Set all the parameters for Size and Resolution (set to SS for small-superfine here), Rotation Setting, and the Field angle/flash settings as shown in the picture Zoom Slider
Remote Shooting Adjust other settings in the Shooting settings tab. You may want to adjust some of these settings to suit your needs. We set Photo Effect to Black & White and sometimes switch AE Mode to Manual if we have dim bands. When the gel is properly framed, click the Release button (encircled) The image will be saved in the folder you selected at application launch
Example Gel Capture Genomic DNA digested with PvuI This image was reduced to 640x480 from the original 1024x768, but otherwise unaltered.
Gel Editing Open the gel file in ImageJ Crop and rotate as desired Run the Gel Converter routine from the Plugins pull-down menu Scale the image as necessary The Gel Converter routine produces an inverted grayscale image of the gel Note: By inverting the grayscale, less ink or toner will be used when the image is printed.
iphoto You can import gel files into iphoto for easier management. Choose File > New Album Choose File > Add to Library... Select files to import Drag and drop the image files into the newly created album iphoto will provide you with exposure information as well as date and time the photo was taken. iphoto can also convert the color images to black and white, and it performs basic image manipulations, such as cropping and contrast.
Notes Be sure to get the correct lens/filter adapter for the Canon camera that you purchase. The orange 099 filter is not a narrow bandwidth filter. Narrow bandwidth filters are substantially more expensive ($200+), but probably give a little better image. Our system is used with an imac G5 (OS X 10.4.3) and Canon software CD version 19. Comments, suggestions, questions and complaints can be emailed to me. I ll do my best to answer questions and address complaints. If you end up using a system based upon this presentation, please let me know so I can score points with my department director! Email: tony.schountz@unco.edu