UVP’s EpiChemi3 Darkroom is a one-stop gel documentation system. There are three basic parts of the system: the darkroom, the camera, and the software. The darkroom has five filters that allow for viewing fluorescent (ethidium bromide, SYBR Green, SYBR Gold) and visible color stains (Coomassie, Silver) in addition to allowing the user to visualize chemiluminescent reactions. The camera system (there are several to choose from) is controlled by hand, giving the user control of the aperature, the zoom, as well as focusing. The real advantage of UVP’s system over traditional visualization systems is the software program that runs the system called LabWorks. Even a new user can quickly learn the steps needed to document a Western blot or an ethidium bromide stained agarose gel. More advanced users will find that Western blot densitometry and 2D gel analysis is also more efficient and easier with LabWorks than with traditional methods.
The first time I used the EpiChemi3 system, I was pleasantly surprised with its ease of use. After placing the blot in the darkroom, I moved to the computer. I selected acquire then video/digital. I set the exposure time to 300 msec and hit preview. Moving back to the darkroom, I turned the aperature on the camera down until I could see my molecular weight markers. Next, I changed the zoom until my blot took up all of the room on the preview screen. Finally, I moved my blot by hand until it was centered. After latching the door to the darkroom, I made sure that the UV light was off, there were no filters in place, and that the darkroom overhead light was off. I also opened the aperature as wide as it would go. The last step in the process was to expose the blot. I chose an appropriate exposure time and clicked on the capture button. Two minutes later I had a white on black image of my blot. Changing the image to a more traditional black on white image required two clicks of the mouse.
Another useful feature of the LabWorks software is the ability to change the display range post-visualization. By narrowing the display range, I am able to see if there is a hint of a band in another lane. If I think there may be another band, I can then expose the blot for a longer period of time.
One of the few drawbacks of this system (and others like it) is that it is not as sensitive as film. This means that exposure times may need to be increased to sometimes double the time required for film. This is less of a problem if you are looking at an abundant protein or if you are willing to make due with less resolution as the software allows the user to adjust the binning. Another of the drawbacks I have experienced is the rather flimsy camera housing. The camera is held in the housing by one adjustable screw that can come loose unexpectedly, causing the camera to drop onto the top of the darkroom (several inches).
J. Jason Clark
Research Assistant
University of Iowa