and the MiniOne
The MiniOne Electrophoresis System was designed to deliver the complete, hands-on electrophoresis experience within the constraints of the classroom lab, without compromising quality or performance. While using the MiniOne System, students will gain an appreciation for the interdependence of science, technology, and design, and teachers will be able to integrate STEM curriculum into their classrooms.
Many common techniques in molecular biology produce DNA fragments of a specific size. Restriction enzymes cut DNA at specific sequences revealing the presence of mutations and clues to ancestry. DNA fingerprinting identifies individuals based on the number of repeated inserts at sites in their genome. PCR reactions produce fragments of a specific length that can be used to identify species or verify the presence of a pathogen in a clinical sample. To analyze the results of these experiments the DNA fragments must be sorted by size.
Electrophoresis is a ubiquitous technique for separating molecules, including DNA fragments, based on size, shape, and electrical charge. An electric field is created by applying a voltage between two electrodes. A conductive buffer provides ions that carry electric current between the electrodes. When placed in an electric field, a positively charged molecule will migrate toward the negative electrode and a negatively charged molecule toward the positive electrode. The DNA backbone contains phosphate groups, which gives DNA fragments a net negative charge. Under the electric field DNA molecules are pushed through an agarose gel, which acts like a sieve. Small fragments move quicker through the pores in the gel while larger fragments move slower.
Electric field strength, conductivity of the buffer, diameter and placement of the electrodes all affect the speed of DNA movement. By placing the carbon electrodes close to the edge of the gel the MiniOne™ System has an electric field strength of 8.73V/cm using a 42V power supply, achieving DNA migration rates similar to research equipment but at a safe voltage.
Technology is constantly evolving and so are the opportunities to use technology in education. Gel electrophoresis has been around for decades but has not been available to educators until the last 10-15 years. Most electrophoresis systems marketed for education are based on the design of research equipment maximizes for resolution and sample numbers and is too slow to see results within a class session. Many educators still rely on donations of outmoded equipment or simple DIY set-ups, neither or which can replicate the quality of results from a research lab. Safety is a constant concern since traditional electrophoresis relies on high voltage, toxic chemicals, and UV light.
MiniOne™ Electrophoresis System is redesigned from the ground up to fit the requirements of educators. By bringing together the convenient built-in power supply of Embi Tec’s RunOne Electrophoresis System and the lateral blue LED illumination of the PrepOne Sapphire Illuminator, MiniOne produces reliable, research-quality results in a format that is fast, safe, and simple to use.
Built-in DNA visualization provides a way to connect the technology of science with the technology that students use in their everyday lives. When mobile phones hit the teenage market, educators found a new source of headache and distraction. When you can’t beat them, join them! The photo hood is designed with pervasive mobile device in mind. The height of the photo hood was determined by testing the focal distance of the cameras in smartphones and mobile devices, allowing students to easily take pictures using their personal devices for homework or lab reports. The hashtag #theMiniOne is embedded in the gel viewing platform. Students can compare their results with classmates on social media, or share their images with MiniOne users around the world.
Engineering is a story of optimization. Equipment for analyzing DNA must be accurate, reliable, and sensitive. In the classroom it must also BE fast, budget-conscious, and meet a very high standard of safety. Reducing the distance between electrodes produces a stronger electric field and faster DNA movement, but get the electrodes too close to the edge of the gel and the gel will melt. The distance between the gel and the electrodes and the size of the buffer reservoir have been optimized to provide fast DNA migration and consistent experimental results. The MiniOne’s conductive carbon electrode provide a durable, lower cost alternative to the traditional platinum wires, while the magnetic safety interlock, non-hazardous blue LED light, and safe 42V power are designed to eliminate hazards for the students.
Optimizing the electrophoresis workflow involved innovations to the prep procedure. Valuable teacher prep-time and class time is often taken up by agarose gel casting. MiniOne GreenGel Cups simplify gel casting and reduce the time for melting the agarose. GreenGel Cups come with agarose, buffer, and GelGreen stain pre-measured. We supply the gel chopped up into small cubes, increasing surface area to allow rapid melting- just 20-30 seconds in the microwave and they’re ready to pour. Reduced gel volume, as a result of optimized gel length to achieve the best resolution, means faster solidification in as little as 10 minutes This speed and simplicity means that students get the full experience of making gels themselves.
Math appears in every stage of your experiment, from diluting the buffers, preparing the gels, calculating voltage, and interpreting results. Plot the migration distances of known fragments on a semi-log scale to create a standard curve, then use this relationship to determine the sizes of unknown fragments.
PCR is a practical application of exponential math. The number of copies of your DNA fragment doubles every cycle. Starting with a single copy, after thirty cycles you will have over a billion! Challenge your students to determine how many cycles they would need to produce a given concentration of DNA.
Concentrated solution that is being diluted.
Diluted solution, ready to use.
Diluent:_Dilution Factor (DF)
The fluid used for diluting concentrate.
Solution used (V1), divided by the total volume of working solution produced (V2). In turn, V2 = V1 + the volume of diluent used.
The dilution factor also gives the relationship between solute concentration in the stock solution (C1) and the working solution (C2).
Dilution factor (DF) = C2 / C1 = V1 / V2
or = C1 X V1 = C2 X V2
Stuff to Remember
V2 > V1
C2 < C1
DF < 1.0 (A “50-fold [50X]” dilution has DF = 1/50 = 0.02)_
When you add 1.0 ml of stock to 4.0 ml of diluent, DF = 1/5, NOT 1/4.