Obtaining High-Quality Acrylamide Gels without Compromises

Researchers frequently analyze protein diversity or specific protein levels within their cell samples by employing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to separate proteins based on their molecular weight. Scientists need high-quality acrylamide gels to achieve the ideal protein separation required for downstream applications, such as mass spectrometry and western blotting.^1,2 Despite their importance, researchers have primarily two choices: buying a precast gel or manually casting a gel. However, these options have distinct advantages and disadvantages. 

Choosing Between Cost and Time

Because of the relatively low cost of the ingredients, homemade acrylamide gels are the most economical choice. Scientists can generate numerous hand-cast gels for the same price as a single precast gel, making the homemade option ideal for laboratories that use numerous gels each week.³ Additionally, researchers who prepare their own gels can customize the percentage of acrylamide to best resolve their protein of interest, where high acrylamide percentages best separate proteins with low molecular weights and vice versa.³ Conversely, commercially available precast gels are only offered in select acrylamide percentages, which may not be ideal for studying particular proteins. The homemade choice also allows scientists to prepare the gels as needed as opposed to requiring the researchers to preplan the quantity of precast gels that they will need in the coming months. 

Although hand-cast gels are far cheaper than precast gels, researchers must endure a time-intensive, multi-step process to manually generate their acrylamide gels, which includes weighing the reagents, mixing, casting, and waiting for the resolving gel to polymerize before they repeat the process for the stacking gel. Because scientists complete these steps manually, there are multiple opportunities for them to produce inconsistencies in their gels, and these problems are far more likely to happen to inexperienced researchers. Moreover, these problems compel scientists to remake their acrylamide gels, potentially negating any money saved by hand-making their gels and forcing them to be further exposed to toxic chemicals including acrylamide, tetramethylethylenediamine (TEMED), and ammonium persulfate (APS). Alternatively, precast gels are reliable, consistent, ready-to-use products, which produce publication-ready results. As a result, researchers reach for precast gels when their protein samples are too precious to risk the experiment failing due to a hand-cast gel.

Finding the Middle Ground 

Scientists have needed to choose between the cost saved using hand-cast gels and the time saved using precast gels until recently. The mPAGE® Lux Casting System from MilliporeSigma strikes a balance between cost and time. Through UV irradiation, this system polymerizes both the resolving and stacking portions of a mini-gel simultaneously in only 90 seconds, which allows scientists to cast gels from start to finish in under three minutes. Consequently, this saves researchers a tremendous amount of time, as the preparation and curing steps normally take between two to three hours with hand-casting.³

Furthermore, pre-prepared resolving and stacking gel solutions eliminate the time spent weighing reagents, while still retaining the flexibility of hand-cast gels because scientists can dilute the resolving solution to the desired acrylamide percentage. Unlike the typical Tris-Glycine-based gels, the mPAGE® Lux Casting System employs the pH-neutral Bis-Tris in their gel solutions, which allows researchers to obtain sharper bands and reduces the gel’s run-time. Instead of APS and TEMED, this system also uses non-hazardous photoinitiators, which makes this gel casting method safer than the conventional hand-casting process.

In addition to these advantages, this system also saves researchers money, as gels generated through this method are cheaper than commercially available precast gels. However, this does not come at the expense of the gel’s reliability because this system produces high-quality, consistent gels, which minimize gel failures and precious sample loss. Overall, the mPAGE® Lux Casting System enables researchers to get publication-quality results in a fraction of the time and money of hand-cast and precast gels, respectively.