Coomassie blue protein gel staining began in the 1960’s, and it’s still a fan favorite in biology labs today. While less sensitive as a colormetric method than silver, or fluorescent staining, Coomassie has undergone a significant revolution in recent years. This post presents a few handy tips for this essential life science pigment.
Economical protein gel detection
For labs where very high volumes of stains are used, it is more economical to prepare your own solutions. Beer, L. A., & Speicher, D. W. recently published a nice overview with a few great protocols here, (see reference 1). Of special note, if you have lab access to infrared fluorescence detection, Coomassie Blue is the most economical way to accurately detect the largest range of proteins, at less than 1 ng sensitivity (3). This yields impressive savings and comparable results to fluorescent dyes!
Unfortunately, most Coomassie based method solutions require some hazardous materials. Hazardous waste leads to higher back end environmental and research costs. The good news is that scientists have cleverly developed “greener” Coomassie blue method tweaks that reduce hazardous waste. For one, please consider mitigating the impact of toxins by using Kimwipes for stain removal, (see reference 3). Also, destaining solution can often be reused by adding a 1x1 inch cellulose sponge to the rocking glass container with the gel in it (1) . Simplicity is good!
For labs staining less SDS-PAGE gels, it tends be be more economical to use time saving commercial stains. Please consider environmentally friendly options below!
Common Coomassie Staining Methods
Coomassie Brilliant Blue (R-250), Colloidal Coomassie brilliant Blue (G-250), Rapid stains and Environmentally friendly
Environmentally friendly Coomassie Blue
Environmentally friendly stains are generally safer for users. No fume hood is required and these can be easily disposed of down the sink. Of course you should continue to wear gloves to prevent protein gel contamination. Eco-friendly commercial stains are also mass spec compatible. There is the issue of proprietary formulas to consider. Most find this acceptable given the consistent reliability. The true caveat is that overall sensitivity may be reduced depending on your samples and the stain used.
Below is a list of commercial Coomassie based stains. Please share your experience using any of these! Thank you for being labconscious!
AMRESCO VWR: Blue Bandit Protein Stain
Biotium: One-Step Blue® Protein Gel Stain
Expedeon: InstantBlue™ Protein Stain
Geno Technology, Inc: LabSafe GEL Blue™
Lonza: ProSieve™ EX Safe Stain
Millipore Sigma: EZBlue™ Gel Staining Reagent
Beer, L. A., & Speicher, D. W. (2018). Protein detection in gels using fixation. Current Protocols in Protein Science, 91, 10.5.1–10.5.20. doi: 10.1002/cpps.48
R. Hussain Butt and Jens R. Coorssen (2013) Coomasie Blue as a Near-infared Fluorescent Stain: A Systemic Comparison With Sypro Ruby for In-gel Protein Detection. MCP doi:.10.1074/mcp.M112.021881
Dorri Y & Kurien B.T. (2018) Paper Adsorbents Remove Coomassie Blue from Gel Destain and Used Gel Stain in an Environment-Friendly Manner.
Methods Mol Biol. doi: 10.1007/978-1-4939-8745-0_30.