Freedom to capture data for studying proteins and nucleic acids.
Traditionally, Western blot detection methods have used X-ray films to capture chemiluminescence. However, the increasing costs for film, reagents, and maintenance made many researchers to shift from darkrooms to more sensitive and technologically advanced digital imaging systems such as Cooled-charge coupled devices (CCD) cameras capturing both chemiluminescence and fluorescence images. The two mentioned detection methods allow the ability to simultaneously detect proteins on the same blot minimizing the need for stripping and reprobing leading to an increase in detection efficiency (Mathews, Plaisance et al. 2009).
Here, I will review Azure Biosystems imaging system for chemiluminescent, fluorescent and infrared imaging, and briefly discuss their advantages and disadvantages.
The Azure Biosystems C600 image analyzer.
C600 system is the only imaging system available in the market currently with the following features (i) infrared laser excitation for quantitative imaging in the near IR, (ii) picogram detection of proteins using chemiluminescence, (iii) wide range of dye selection with Cy?5/Cy3/Cy2 excitation, and (iv) option of upgradation from the base units c200, c300, c400 and c500. This increases the options of selecting different chemistry for performing Western blots by using the same imaging system. Due to the signal stability and low background, detection in the near-infrared fluorescent (NIR) for Western blot detection is achievable using the infrared fluorescent dyes. The NIR western detection also offers multiplexing allowing the option to detect multiple proteins at the same time. Azure Biosystems’ c600 system is equipped with two IR detection channels and allows users to study multiple proteins with overlapping in a blot. The image generated can be spectrally separated as the secondary antibodies are imaged in two different channel.
We have compared the image obtained and the analysis results were comparable to other laser detection system e.g. LiCOR odyssey Western blot imaging system.
Chemiluminescence continues to be a favorite and sensitive method of detection. Azure c600 provides quantitative analysis with accurate, fast detection with superior sensitivity, dynamic range, and linearity needed for quantitative blot analysis by chemiluminescent means made possible due to the use of the high resolution, F 0.95 fast lens technology. The superiority of the analyzer is evident from the availability to use any HRP substrate allowing users to maintain the same protocol and capture images with the same sensitivity as film without the risk of oversaturation due to the broader window of detection of several orders of magnitude of protein concentration. The c600 can also be equipped with powerful LEDS for Cy5/Cy3/Cy2 imaging or similar dyes thus allowing the users the option to expand multiplexing. The c600 is also able to image a wide range of dyes (excitation maxima from 302 nm to 785 nm), enabling WesternDots?, Stain-Free? gels and different types of in-gel fluorescence.
The c600 system also is of immense to molecular biologists with the inclusion of UV, white, and blue lights for imaging Ethidium bromide, Coomassie, and non-mutagenic dyes like Gel red and Gel green.
Azure c600 machine offers great value for the money as it combines the functionalities of laser NIR imager with chemiluminescent camera in one simple affordable machine.
The after sales service provided by Azure Biosciences is of highest professional standard, with arrangement of hands-on training beginning from installation to detailed explanation of functioning of the machine. The technical team took into consideration about minor technical information while explaining the functioning of the Azure spot software. We had faced problem once with regards to the software and it was promptly resolved by the Azure Biosciences team.
The technical team is also helping us to explain the analysis beyond Westerns to analyze multiplexing on glass bead format as is available for the analysis of many cytokines and key molecules from many supplier as well as thick tissues pre-labelled with dye probe e.g. GFP protein.
Source: Mathews, S. T., E. P. Plaisance and T. Kim (2009). Methods Mol Biol 536: 499-513.
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Transplantation Biology Lab, Dept. of Surgery, University of Gothenburg