In the past five years, we have used three generations of Alpha Innotech machines. Originally, we were using an older machine in the lab next door, however, when that lab decided to leave, the floor needed to get a new gel imager. After looking at several different models, we decided to purchase a new AlphaImager™, since everyone was very pleased with the quality and ease of use of the older machine. A year or so later, the lab that actually purchased the machine moved as well and we decided to purchase a third AlphaImager™.
Alpha Innotech has several different models with varying capabilities. We have the generic AlphaImager™ that we primarily use to take pictures of ethidium bromide stained DNA gels (additional filters can be added for other stains like SYBR green, but we do not have these filters). Alpha Innotech also offers a machine with a better 12-bit camera (AlphaImager™ HP) and machines that can visualize chemiluminescence (FluorChem family). AlphaImagers™ are designed with a stand-alone cabinet and use an external computer so a darkroom is not needed. Taking pictures with this machine is incredibly easy. The machine has reflective white lights that allow you to align and focus the gel under the camera. Once the gel is in focus, the white lights are turned off and the UV light is turned on (as a safety precaution, UV light will only turn on if the cabinet door is closed). You then expose the light to the camera, during which time you can change the exposure time to increase or decrease signal (machine has an auto-expose feature as well). Once the image looks satisfactory, the image is acquired and the UV light automatically shuts off. Images are printed on thermal paper (rolls are pretty large and costs about 20 dollars a roll which is not too bad) using an attached printer that is bought along with the machine. It is also possible to take pictures of Coomassie stained protein gels using the white lights included inside the cabinet. In reality, you can take a picture of almost anything you want, assuming it will fit into the cabinet.
All of the features used to acquire an image are controlled by the computer interface (you can turn the lights on and off using buttons on the cabinet as well). The older machines used a manual camera, so the zoom, focus and aperture could be set using your hand. The newer machines use a motorized camera, so all of these settings are done through the software. Personally, I like the old design slightly better, since I could get the gel in focus a little faster, but this is not really a problem as the new design is still fast, works extremely well and the camera is never touched. In terms of gel analysis software, the machine comes with a whole suite of features, most of which we do not utilize at the moment. Once you have acquired your image, the software has several different, enhanced features built in, so you can find the setting that makes your gel look the best. Otherwise you can play around with the settings to improve the quality of the image. An easy to read manual is also included when you purchase the machine to help you learn the different features of the software.
The only disadvantage of this machine is that it might be a little more expensive than some of the other machines on the market. We bought our machine over a year ago, so I don’t know how the prices compare today. As a precautionary measure, we do not cut out gel fragments in this machine – we use a cheaper UV gel box for this purpose. Although, we really only take pictures of ethidium bromide stained gels and don’t use many of the features of this machine, the quality of the images and the ease of use make the AlphaImager™ a fantastic machine that is heavily used and highly recommended.