The E-Gel EX system is an integrated platform for agarose gel electrophoresis, a technique used to separate DNA fragments by size. It is designed to accelerate DNA analysis by providing pre-cast, self-contained gels that simplify the traditional workflow. This system is intended for rapid, routine checks of DNA samples.
The E-Gel EX System Components
The E-Gel EX system is composed of two primary elements: the disposable gel cassette and the hardware device that runs it. The E-Gel EX cassette is a self-contained, single-use unit. Inside the plastic housing is the agarose gel, along with electrodes and a solid, pre-mixed buffer. This “bufferless” design eliminates the need for scientists to prepare liquid running buffers.
A feature of the cassette is the inclusion of a DNA stain, such as SYBR Safe or SYBR Gold, directly within the gel matrix. This integration removes the requirement for a separate, time-consuming post-electrophoresis staining step. The entire cassette is ready to use straight from its packaging.
The second component is the E-Gel PowerSnap Electrophoresis Device. This device provides the electrical current that drives the negatively charged DNA molecules through the gel. It also incorporates a built-in imaging system, which includes a blue-light transilluminator and a camera, allowing for real-time visualization of the DNA separation and capture of the final gel image.
Running a Sample
The workflow for running a sample on the E-Gel EX system is streamlined. A researcher begins by preparing the DNA samples, which involves mixing a small volume of DNA with a loading dye, and preparing a DNA ladder, a mixture of DNA fragments of known sizes for comparison. The process starts by opening the sealed pouch containing the E-Gel EX cassette and removing the plastic comb from the gel, which reveals the sample wells.
Using a pipette, the prepared DNA samples and the ladder are loaded into their designated wells within the cassette. Once loaded, the cassette is inserted into the E-Gel PowerSnap device. Closing the lid engages the electrical contacts and secures the cassette for the run.
The user then selects a pre-set program on the device’s interface, which is optimized for the specific type of E-Gel being used. The run begins immediately, and the entire process, from loading to final result, can be completed in as little as 10 to 15 minutes. Researchers can monitor the progress of the DNA separation in real-time on the device’s screen. When the separation is complete, a high-resolution image of the gel is captured and can be saved for analysis.
Key Applications
The E-Gel EX system is utilized for routine and high-throughput analysis of DNA fragments where speed is a priority. One of its most common applications is the analysis of Polymerase Chain Reaction (PCR) products. After performing a PCR to amplify a specific segment of DNA, scientists use the E-Gel EX to verify if the reaction was successful and confirm that the resulting DNA fragment is of the expected size.
Another use is for screening restriction enzyme digests. This process involves cutting a larger piece of DNA, such as a plasmid, with specific enzymes. The E-Gel EX allows for a rapid check to ensure the DNA was cut correctly into the predicted fragments. This verification is a common step in molecular cloning workflows.
The system is also well-suited for general DNA fragment sizing and quantification. Researchers can determine the size of a DNA sample or get a rough estimate of its concentration. Its utility extends to checking the integrity of RNA samples before they are used in more sensitive downstream applications.
Comparison with Traditional Gel Electrophoresis
The most significant difference from traditional methods is the speed and convenience of the workflow. A traditional gel requires weighing agarose powder, melting it in a buffer, pouring the molten gel into a casting tray, waiting for it to solidify, submerging it in a buffer-filled tank, loading samples, running the gel for 30-90 minutes, and finally staining it. This multi-step process can take one to two hours, whereas the E-Gel EX workflow is reduced to about 15 minutes.
Safety and waste reduction are also advantages. Traditional electrophoresis often involves handling ethidium bromide, a potent mutagen for staining DNA, and generates liquid buffer waste. The E-Gel EX system’s pre-cast cassettes contain a less hazardous stain like SYBR Safe and feature a bufferless design, minimizing contact with harmful chemicals and reducing liquid hazardous waste.
The pre-cast nature of E-Gels contributes to higher reproducibility. Hand-poured gels can have slight variations in thickness, agarose concentration, and buffer consistency, which can affect the migration of DNA. The standardized manufacturing of E-Gel cassettes ensures that results are more consistent from one run to the next.
The primary trade-off for these benefits is cost. The price per sample for an E-Gel EX cassette is higher than the cost of the raw materials—agarose powder, buffer salts, and stain—used for a traditional gel. This cost difference positions the E-Gel EX system as a premium option where the value of speed, convenience, safety, and reproducibility outweighs the higher price of the consumables.