When working with proteins and DNA, one of the first steps in any work flow or experiment is to separate the biomolecules by size on a SDS-PAGE or agarose gel. Following electrophoresis, biomolecules are typically stained with fluorescent or colorimetric stains to visualize bands. In the past, gels were either dried and kept as a record or photographed; however, now imaging instruments such as scanners are more prevalent. Because a digital record of the gel is more convenient for obtaining publishable images, the need for versatile, low cost, personalized scanners and imagers has increased.
Alpha Innotech’s Red™ Imaging System is a quality UV transilluminator and white light imager for capturing images of stained DNA and protein gels. The instrument takes up the same bench area as a flatbed scanner. The unit has built-in software and a user friendly touch screen interface allowing the Red Imager to be a stand alone unit that does not require a computer connection. This cuts down on the required bench space and the need for yet another computer in the laboratory. Images can be saved to a network through a LAN connection, a USB flash drive or printed directly by connecting a digital thermo printer.
The Red Imaging System captures quality images of stained gels with minimal adjustments. The operator can select the illumination source (UV transilluminator or white light), aperture, zoom, focus and exposure time. The simple interface makes image acquisition quick and easy. The imaging system gives you a numerical output for the exposure time but it would be beneficial to also have numerical outputs for the aperture, zoom and focus settings. The Red Imaging System produces excellent images of protein gels stained with fluorescent UV excitable stains (Figure 1) and fluorescent DNA stains using the UV transilluminator. When imaging colorimetric stains (e.g., Coomassie and silver stains), the Red Imager-acquired images are of similar quality to a flatbed scanner. The image is captured in about half the time required to adjust levels and scan images on a flatbed scanner. The red Imaging System uses LED white lights mounted in the back of the instrument to illuminate the gels which results in a slight exposure gradient across the gel (Figure 2).
Overall, Alpha Innotech’s Red Imaging System captures quality digital images of protein or DNA stained gels with a UV transilluminator and/or white light. The image acquisition process is a motorized and computer-controlled operation except for the filter wheel which requires manual manipulation. The imager offers convenient touch screen interface and is compact, requiring the same bench space as a digital scanner, but also provides UV transilluminator capabilities.
Figure 1. UV Transilluminator Imaging of Fluorescently Stained Protein Gel
Serially diluted protein standard stained with Thermo Scientific® Krypton™ Protein Stain was imaged with the Alpha Innotech’s Red Imaging System using the UV transilluminator.
Figure 2. Imaging of Coomassie Stained Gel Using White LED Illumination
Green Fluorescent Protein (arrow) was enriched by immunoprecipitation using Thermo Scientific Pierce® Direct (D), Classic (C), and Crosslink (X) IP Kits. The samples were electrophoresed and stained with Thermo Scientific Imperial™ Protein Stain and imaged using the Alpha Innotech’s Red Imaging System using the white LED illumination.