Featured Article
Wednesday January 06, 2010
By Caitlin Smith
Have you worked in a lab long enough to remember taking a Polaroid shot of your gel, and taping it into your lab notebook? Gel documentation has since become much more high tech. “The field has come a long way from the old manual Polaroid method,” agrees Walter Ausserer, VP of marketing at Cell Biosciences.
That’s good, right? Some might disagree, in the sense that taking a picture of a gel is much easier than using some of the first gel documentation systems that clunked onto the market. Fiddling with camera settings and lighting conditions to get a picture of what your eyes already see can be frustrating. “Historically, gel documentation system users have come to expect to spend a significant amount of time and a large degree of fine-tuning to optimize the quality of their image,” says Ryan Short, imaging systems marketing manager at Bio-Rad Laboratories. “Furthermore, algorithms used to automate analysis have not been robust enough for the researcher to have confidence in the results generated. Image acquisition and analysis should not require a high level of expertise, or take more than a few seconds.”
Luckily, the technology of gel documentation systems continues to evolve—now with ease of use maximized and user input minimized. In fact, automation technology for imaging and advanced software routines for analysis are making the user increasingly obsolete. “Imaging will become more and more automated with intelligent software controlling many areas of data capture and analysis,” says Bob Coyne, product and sales support specialist at Syngene. Of course, a careful measure of user oversight is prudent, but increasingly, users of these new and improved gel documentation systems are breathing sighs of relief.
Built for endurance
For many labs, a gel documentation system is a dedicated workhorse, a crucial piece of equipment for multiple users per day, every day. Carestream Molecular Imaging emphasizes the construction of their systems such that they can withstand the daily toll and keep on chugging away. “We focus on designing our gel imaging systems as bulletproof workhorses that can deliver years of reliable service,” says Craig Smith, product manager of in vitro imaging systems at Carestream Molecular Imaging. “To that end we use high quality CCD cameras and quality parts for our cabinetry. An example of this is evident with CMI’s Gel Logic 212 Pro system. Many competitor systems use rubber gaskets, but we have engineered a metal labyrinth lock around the lens. The rubber gaskets can loosen and as they wear out, light leaks can create artifacts on the images. CMI’s labyrinth lock prevents light leaks and provides greater longevity.”
Carestream also designs their software to have complete motorized and automated control of imaging. “Our unique autofocus capability uses advanced analytical algorithms to deliver perfect focus for each image,” Smith says. “Full motorization and automation also controls filter wheels and light sources. Our Gel Logic platform also supports user-defined settings that include selections for filters, lenses and light sources so users can load a series of samples and just hit capture for each image. We also have a quick print button for situations where users just need a quick image printout for a series of samples.”
Like Carestream, UVP also incorporates motorized controls into their BioSpectrum Imaging Systems, one of a series of gel documentation systems offered by UVP. “The BioSpectrum Imaging Systems provide a fully motorized lift for sample placement and management, a series of fully motorized lenses to choose from to enable the proper optics for colorimetric, fluorescence, or chemiluminescence sample imaging, full computer control of built in epi and trans UV lighting, and complete image acquisition management of camera operations to enable full use of individual camera architectures,” says Alexander Waluszko, VP of marketing and sales at UVP. In addition, UVP’s BioLite ™ Light Engine expands the BioSpectrum’s epi and trans lighting capabilities 100-fold. Waluszko says that full automation of this system “enables full spectral imaging from UV through Vis and into near IR for sample excitation and image capture.”
Simplification for greater productivity
Bio-Rad’s gel documentation line aims to simplify your workflow. Their new acquisition and analysis software Image Lab, for their GelDoc XR+ and ChemiDoc XRS+ imaging systems, is designed to let you take images without fiddling to determine optimal settings for the camera and lighting. “The GelDoc XR+ and ChemiDoc XRS+ imaging systems are calibrated to ensure that all images are always in focus, and that other camera and light settings are automatically determined based on the users’ application,” says Short. “Personalized protocols help the user to create images with maximum consistency and reproducibility, thereby adding a new level of data quality to their experiments.”
Bio-Rad’s new Criterion Stain Free Gel Imaging System can also save you time, as it uses precast gels that let you visualize protein sample in as little as 2.5 minutes. “Many staining techniques such as Coomassie require multiple-step, time consuming procedures that involve rinsing, staining, and destaining,” says Short. “This can add two hours to any experiment before the gel can be imaged and analyzed.”
Cell Biosciences’ gel documentation system is also designed with ease of use in mind. “Our goal is to make gel documentation as quick and easy as possible,” says Ausserer. “Our red™ Personal Gel Imaging System is an integrated unit that combines touch-screen controls, a small footprint, and simple data transfer via USB memory sticks. It is the perfect system for multi-user labs imaging DNA, RNA, and protein gels with a wide variety of fluorescent labels, plus white light imaging.” Their system also facilitates gel documentation by storing multiple protocols for different lab members. In addition, Ausserer says that they built their systems with the idea of eliminating toxic intercalating dyes. “We've designed our systems to work with nontoxic dyes such as SYBR Safe,” says Ausserer. “There really is no reason to use ethidium bromide any more for DNA imaging.”
Intuitive brains and motorized controls
Syngene has packaged an acquisition and analysis computer into their new stand-alone gel doc system, the U:Genius. “A full PC is built into this small footprint imager to allow for data storage, image processing, and archiving of data to the user's network,” says Coyne. They also have a new technique for chemiluminescent imaging called iChemi. “This new automated capture technique provides maximum counting time for weaker bands to develop without saturation of stronger bands in the sample. Colorimetric markers are imaged immediately after the chemiluminescent image is acquired and a composite image is automatically generated.” Syngene emphasizes developing intuitive software that can capture the desired image by automatically selecting the correct filter, illumination module, and exposure time—all based simply on the type of sample you select from pre-programmed applications.
Coyne thinks that notable recent developments in gel documentation include fluorescent imaging techniques for multi-label Western blot analysis. “Syngene's G:Box series can be outfitted with lighting and filters to allow imaging of many fluorescent labels, including Qdots and Alexa and DyLight dyes from the blue to infrared wavelength ranges,” says Coyne. “Multi-label fluorescent Westerns and chemi-labeled Westerns can now be measured on a single imager, giving our customers the broadest range of imaging modes available in the market today.”
Today’s gel documentation systems can probably save you time—though some might want to keep that Polaroid camera around a little longer, just in case.