RNA isolation from minute samples can be a real challenge. The precipitated RNA pellet is usually barely visible and can be easily lost. And since the source material is often only available in small quantities, it can be difficult to increase the mass of the pellet. RNA isolated from samples like this is obviously very precious, thus optimizing the procedure and ensuring that the RNA will not be lost is very important. To help with this, Ambion’s GlycoBlue is a fantastic aid in isolating RNA from very small samples. Its application can not be easier and there is no need to extensively modify an existing protocol. Simply add a small amount (typically 1-2 ul to have a final concentration of 50-150 ug/ml) of GlycoBlue to the reaction during the isopropanol precipitation step and at the end you will have a nice, clean, easily visible blue pellet of RNA. Moreover, GlycoBlue does not decrease the quality of isolated RNA, nor hamper with 260/280 readings and it does not interfere or compete with subsequent enzymatic reactions.
GlycoBlue is an inert co-precipitant consisting of a blue dye covalently linked to glycogen (isolated from mussels) and extensively treated to remove any nucleic acids as well as DNases and RNases contaminants. The chained carbohydrate branches of glycogen help RNA to precipitate into a pellet, while the blue dye makes the pellet visible at the bottom of the microcentrifuge tube.
I am isolating RNA from very well-defined brain regions of a few microns in size, undergoing specific treatments, which gives me very small samples to work with. Usually, without GlycoBlue™ I don’t see the RNA pellet and obtaining it can be a gamble, increasing the chance that the complicated experiment can fail at one of very first steps. The simple addition of GlycoBlue™ during alcohol precipitation makes my life much easier. The position of the pellet is very well defined and easily visible. Additionally, GlycoBlue™ increases the yield of RNA isolation, which is also very important when dealing with the very small samples.
There is really no downside to using GlycoBlue, although one may consider that GlycoBlue adds extra cost to the RNA isolation. By using 1-2 ul per one RNA isolation, one GlycoBlue vial should be sufficient for 150-300 isolations adding an extra 15-30 cents to each reaction.
Overall, the Ambion’s GlycoBlue is a great, economically priced aid in isolating RNA. I am very pleased with this product and would recommend it to other labs, which need to isolated high quality RNA from very small samples.
Andrzej Pietrzykowski, M.D.
Post Doctoral Fellow
Department of Neurobiology
University of Massachusetts Medical School
Worcester, MA