Immunoblotting, or “Western Blotting”, is a standard laboratory assay used to detect specific immobilized proteins. To resolve proteins, native or denatured protein samples are separated on Tris-glycine gels containing a desired acrylamide concentration. Higher acrylamide concentrations are used to resolve a larger range of protein sizes (typically >10-12%), whereas lower concentrations resolve a smaller range (typically ~8%). Since Tris-glycine acrylamide gels are used frequently in any laboratory that works with proteins, they are often prepared fresh immediately before use. Many companies have made the western blotting procedure more efficient and user-friendly by developing popular gel tank systems that run mini-sized acrylamide gels. Because the steps involved in casting a set of acrylamide gels can be somewhat time-consuming, many laboratories have prepared batches of pre-cast acrylamide gels to save time. Unfortunately, the shelf life of these pre-cast gels is rather short. The scientist who frequently needs to jump right into an immunoblotting assay without the hassle of trying to pour their own gels should therefore consider using Gradipore’s Tris-Glycine Pre-cast iGels.
The Gradipore iGels come in three different acrylamide concentrations (8%, 10%, and 12%) and two gradient gels (4-20% and 8-16%). The gels are encased in a patented plastic cassette that can be disposed of after use. Each iGel has 10 pre-cast sample wells that can fit up to 50ml of sample volume. There are 10 iGels per set, and each are individually-wrapped in a sealed packet containing Tris-HCl buffer that preserves the gel. The stated shelf-life of each iGel is four months from manufacture date, and the date is conveniently listed on both the package and on the gel cassette.
In my experience, the Gradipore iGels separate proteins wonderfully and are easy to use. I have not encountered any difficulties with the separation of denatured proteins or their subsequent transfer to nitrocellulose filters. After I finish separating my proteins, I simply dispose of the gel cassettes—there are no glass plates to clean. The iGels are compatible with the popular 10cm gel tanks, such as the BioRad Mini-Protean, Novex X-Cell, and the Hoefer Mighty-Small systems. I use the Bio-Rad Mini-Protean gel tank set-up, and the iGels simply slide right into the cassette holder. There are no well-casting combs to pull out, and the pre-cast sample wells are clearly visible for easy loading of protein samples. Although Gradipore claims that iGels provide faster run-times when compared to conventionally-prepared gels, I did not notice an obvious difference. Also, performing a Western blot with ease and efficiency comes with a price—Gradipore iGels are not cheap. Nevertheless, I would not hesitate to recommend this product.
Joe F. Lau
Graduate Student
Mount Sinai School of Medicine, NY