The ElectroPrep™ The ElectroPrep™ system from Harvard Apparatus is an extremely versatile patented sample preparation technology based on the principles of electrophoresis and dialysis. This ElectroPrep™ system is ideal for the rapid purification of proteins, nucleic acids, carbohydrates and other biological molecules. With a run-time of 5 to 10 minutes, ElectroPrep™ provides speed and convenience, even at the very low 5 to 10mA currents used with this system. The sample chambers are made of Teflon, a completely inert material especially suited to high sample recovery. Membranes with molecular weight cut off points (MWCOs), ranging from 100 to 300,000 Daltons, may be used in combination with different Dialysis and Link Chambers for selective elution, filtration, dialysis, fractionation and concentration of complex samples, while Union chambers enable different Dialysis Chambers to be joined together to increase sample volume. How to select your chamber and membrane configurations?
1. Decide upon your application - e.g. electroelution, electrodialysis, electrofiltration or electroconcentration
2. Select a Dialysis Chamber able to accommodate the desired sample volume - e.g. 50, 100, 200, 500, 1000 or 1500 µl - N.B. a Dialysis Chamber can be joined to a Union to increase the sample volume
3. Choose membranes with the appropriate MWCO, depending on the technique being performed (see I to IV) and the molecular weight of the biological molecule of interest dialysed product), taking into account each membrane's suitability for use in aqueous solutions or organic solvents
- For organic solvents, use either regenerated cellulose or polycarbonate
- For aqueous solutions, use cellulose acetate
4. Connect the Dialysis Chamber via a
membrane and Union to another Dialysis Chamber for electrofiltration (I) or electroelution (II); a Dialysis Chamber of smaller volume can also be attached to concentrate the dialysed product (III)
5. When desalting PCR® products, membranes can be secured at each end of the Dialysis Chamber by Teflon end caps (IV)
6. Link chambers can be attached to the
Dialysis Chamber via a membrane to filter samples according to their size; multiple link chambers can be used with different membranes for sizefractionation of different dialysed products | (I) Rapid and Selective Electro-Filtration / Concentration The sample is placed in a compartment comprising the Dialysis Chamber (1) and the union. The MWCO of membrane (b) is larger than the molecular weight of the biological molecule of interest, while the MWCO of membrane (a) is smaller. Upon application of the electric field, the biological molecule of interest will pass through membrane (b) and collect in Dialysis Chamber (2) while smaller molecules will pass through membranes (a) and (b) and Dialysis Chamber (2) as a result. This is a fast and effective method for the concentration of small samples as well as selective filtration. |
|  | (II) Gel extraction of DNA and protein by Electroelution By using the ElectroPrep™ system as shown in the schematic diagram, proteins and DNA can be eluted from a gel slice quickly and easily with excellent recovery. By using a Union, Dialysis Chambers can be joined in any combination necessary to accommodate the size of the gel slice. Samples can be concentrated if desired, by choosing a receiving chamber with a smaller volume. The MWCO of the membranes (a and b) can also be chosen to achieve very selective filtration. Membrane (b) should have a MWCO greater than the molecular weight of the sample of interest, while membranes (a) and (c) are smaller. The same principle applies as described in (I). |
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 | (III) Selective Electro-Filtration / Concentration / Separation Based on Different Charges of Biological Molecules In this configuration of the ElectroPrep™, the sample is placed in a Union between two membranes (b), both of which should have a MWCO larger than the molecular weight of the molecule of interest, while the MWCOs of membranes (a) and (c) are smaller. Each biological molecule, including the molecule of interest, will then move either to Dialysis Chamber (1) or Dialysis Chamber (2), depending on its respective charge polarity (i.e. positive or negative), whereas those biological molecules with molecular weights lower than the sample of interest will migrate through membranes (a) and (c) into the tank. Biological molecules with unknown isoelectric points can also be separated and purified in this manner. Dialysis Chambers of smaller volumes can be used to concentrate dialysed product. |
|  | (IV) Electrodialysis through Simultaneous Exchange of Buffers - e.g. cleaning up PCR®products Following amplification, the PCR® product is placed in the Dialysis Chamber between membranes (a) and (b), each membrane having a MWCO lower than the molecular weight of the PCR? product but not the primer. Upon application of the electric field, dialysis occurs quickly by the simultaneous exchange of buffer, resulting in the migration of the lower molecular weight primers through membranes (a) and (b) while the purified PCR? product is retained in the Dialysis Chamber. Electrodialysis is also effective for desalting neutral molecules that do not move in an electric field (such as sugars) or charged molecules at their isoelectric point. |
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Fast dialysis times | due to rapid movement of charged molecules in an electric field | Re-usable | Different chambers | for large or small sample volumes | Membranes available | with MWCOs to suit almost any application or molecule size | Easy to use | Leak proof | Autoclavable | Inert Teflon construction | minimises non-specific protein and nucleic acid binding to the sample chamber, enhancing sample recovery | Highly versatile | can be adapted for multiple dialysis applications | Applications | Electroelution from gels and solutions - e.g. gel extraction of vector and insert during cloning
Electrodialysis (with an average buffer exchange time of 5 to 10 minutes)
On-line electrodialysis
Electroconcentration
Selective electrofiltration
Size-fractionation of DNA and proteins from complex lysates
Primer removal following PCR® amplification
Salt removal from DNA mini-preps
Detergent removal
Dye-Terminator removal |
Unit OnlyElectroPrep™ Tank, including 4mm shrouded power connectors | EP-74-1101 | please contact us |  |
Replacement Parts & Accessories2 x 1-metre power leads with shrouded 4 mm power output connectors | CABLE-4 | please contact us |  |
Unit Dimensions (WxLxH) | 12.5x25x14cm | Internal Dimensions (WxLxH) | 9.5x20x8cm | Buffer Volume | 1500ml | Recommended Running Conditions | 5 to 10mA; 10 minutes run-time | Power Output Connectors (diameter) | Shrouded, 4mm | Recommended Power Supplies | Consort EV243 |
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