Gel Documentation

Nucleic acid and protein gels are a fundamental part of lab life. Gel documentation is a method used to record and measure labeled nucleic acid and protein in various types of media, like acrylamide, agarose, or cellulose. DNA or RNA is usually stained by ethidium bromide, which intercalates into the nucleic acids and can be visualized with UV light.

Examples of dyes that can imaged using blue light: SYBR® Safe, SYBR® Gold, SYBR® Green. These are safer dyes for staining DNA that are growing in popularity.

UV Imaging Ethidium Bromide
UV Imaging
Ethidium Bromide

How gel documentation systems image DNA and protein gels

A gel documentation system (also nicknamed gel doc, gel image system or gel imager), is a piece of capital equipment used in molecular biology for the documentation and imaging of nucleic acid and proteins to gather more information on the genetic information stored in DNA.

A gel doc is used to image and document the genetic information from nucleic acids and proteins suspended within polyacrylamide or agarose gels. We outline the advantages of using a gel doc system compared to using film in Table 1.

Read more: 10 features to consider when shopping for your next gel doc

Table 1. Benefits of using a gel documentation system

Benefits of using a gel documentation system for detecting proteins
Saves time and can reduce overhead cost
Less exposure to harmful chemicals
Gives quantitative data
Supports fluorescent detection for multiplexing
Produces higher-resolution images
Ability to access more applications (such as visible gel imaging, Western blotting, total protein normalization)
Able to image more stains
Advanced software makes it convenient to save and share data

Protein purification procedures often rely on verifying purity by SDS-PAGE and subsequent gel staining (Coomassie blue or silver stain) to check for contaminating protein bands. Gel documentation system are able to record and measure labeled protein and nucleic acid present across different media, such as cellulose or agarose.

Many stains, including TotalStain QAzureRed, Coomassie Fluor™, Deep Purple™, SYPRO® Ruby, SYPRO® Red, SYPRO® Tangerine, and more can be imaged using advanced digital imagers, such as chemiSOLO, or select Azure Imaging Systems.

Scientist standing next to Azure 600
The Azure 600 gives you the flexibility you need for your research, while delivering solutions for quantitative Western Blot imaging. Azure Biosystems provides a unified Western Blot workflow, from the high-performance imaging system and analysis software to the reagents and consumables.

What is the best gel documentation system?

The newer generation of imaging systems often contain sophisticated cameras that exhibit a broader dynamic range than film, thus avoiding the signal saturation problems that limit the dynamic range of film.

You should know the main features of a gel doc before making sure it’s the right one for your lab. Table 2 below gives a general outline of the features you should be aware of, and compares them with the characteristics of the Azure 600 Imaging System. We believe Azure Imagers are the perfect solution for high-performance gel documentation and analysis of gels.

For example, the Azure 200 has the imaging capabilities for many applications. With a dual-wavelength 302 nm and 365 nm UV transilluminator, ethidium bromide-stained DNA gels can be imaged in a fraction of a second. For excising bands from a gel, the UV transilluminator platform can be pulled out.

Choose a gel doc based onThe Azure 600 Imager has
SensitivityTwo channel, laser-based IR and chemiluminescent detection, with the speed and sensitivity of film
Wider Dynamic rangeHigher pixel well cap for higher dynamic range (4.8 OD dynamic range)
Supported detection typesLaser technology with two IR detection channels enabling you to image more than one protein in an assay. It provides accurate and fast chemiluminescent detection, as well as the sensitivity, dynamic range, and linearity needed for quantitative blot analysis.
Gel doc sizeA small footprint of 42 x 56 x 33 cm. This small size translates into saving you more room on your bench.
Software ease-of-useSoftware with preset protocols that also allows you to generate your own custom protocols combining any excitation source, emission filter, image overlay, lens aperture, exposure time, focus, distance to the camera, and resolution

Table 2. Features of a gel documentation system that you should be aware of when purchasing

The Azure 400 and Azure 600 imagers, as well as the Azure Sapphire FL Biomolecular Imager, open up the ability to document protein gels stained with a wide variety of fluorescent protein stains that fluoresce in the visible spectrum.

 Finally, fluorescent dyes are relatively stable; blots can be archived and imaged months after the initial experiment as long as precautions are taken to avoid photo-bleaching of the fluorophores.

Azure imaging systems offer:

Learn more about the Azure Imaging Systems, including full product specifications, user manuals and resources.

Frequently Asked Questions about gel documentation

Gel docs usually contain UV transillumination that excites dyes from beneath the area the sample is placed. The light travels through an emission filter to a high-resolution camera where an image of the sample is collected. Gel documentation systems are essentially enclosed darkrooms that block external light from entering the inside in order to image gels,  Western blots, tissues, arrays, and more.

Azure Imaging Systems use CCD cameras with fast lens options, auto detection, and 4.8 OD dynamic range to capture images. Learn more

Polyacrylamide gels form a crosslinked, mesh-like matrix through which proteins migrate with the application of current. The matrix functions like a sieve, allowing smaller, low molecular weight proteins to migrate quickly through the gel, while large, high molecular weight proteins tend to progress more slowly. When the electrophoresis is finished, proteins in each lane will be separated into a continuum, with the highest molecular weight proteins remaining near the loading site and the lowest molecular weight proteins reaching the opposite end of the gel. Read 6 tips on troubleshooting band separation

Proteins travel effectively through the gel matrix based exclusively on size.

During electrophoresis, proteins travel through a gel matrix with small pores, inside a small box, which is usually used in scientific labs. An electric current pushes the proteins through different pHs as they travel throughout the gel. The current acts like a little helper in each lane, pushing the proteins to their equilibrium state, where they won’t move. Learn more about SDS-PAGE


New to Western blotting? Need to troubleshoot your Western blot?​ Want to brush up on Western blotting best practices? Claim your free Western Blotting eBook!

Systems for Gel Documentation

A portable, personal chemiluminescent Western blot imager controlled by mobile device

Flexible gel docs for Western blots, DNA gels, and more

Laser and CCD-based scanning system for in-cell Westerns, Western blots, gels, and more

Related Applications

Looking for a full list of applications?

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