Design Your Own Electroporation Protocol Episode 3 - Scaling Up and Down
By Michelle M. Ng, Ph. D.
This is the third post in a series where we are providing tips for developing or improving your own electroporation method.
There is some room for scaling electroporation volumes up and down just by switching cuvette gap sizes.
- 1 mm gap cuvettes accommodate small volumes (20 to 90 µl)
- 2 mm gap cuvettes accommodate medium volumes (40 to 400 µl)
- 4 mm gap cuvettes accommodate larger volumes (80 to 800 µl)
The process of scaling up and down between different sized chambers of roughly the same dimensions (such as cuvettes) is simple. You just want to adjust your voltage while keeping the field strength in V/cm and other parameters constant.
Example: You typically electroporate your cells for a single pulse, 5 msec, 250 V in a 2 mm gap cuvette, but would like to convert to a 1 mm or 4 mm gap cuvette. When converting these settings from a 2 mm gap to a 4 mm gap cuvette, you would want to electroporate your cells for a single pulse, 5 msec, 500 V. And in order to convert these settings from a 2 mm gap cuvette to a 1 mm gap cuvette, you would want to electroporate your cells for a single pulse, 5 msec, 125 V.
For even larger volumes you will need to move to a different type of chamber. You may use the same rules above about adjusting voltage parameters to achieve the same field strength when moving from cuvettes to a different style chamber, however keep in mind you may also need to do some protocol fine tuning to optimize for the different geometry of the chamber. For reference, the parameters normally used for a 4mm gap cuvette would also be a good starting point for a 10 ml volume, 4 mm gap large volume electroporation flatpack.
Note: Keep in mind as you increase volume you also increase conductance of your sample. This means more heating of the cells during the electroporation pulses which can cause cell viability issues. To combat this effect you may want to consider using a low conductance electroporation buffer and/or experiment with prechilled buffer for larger volume electroporations.
Our next post in this series will be Episode 4 - Temperature Considerations
Click here to visit our Protocol Database, for electroporation protocols searchable by, system, cell/tissue type, application/transfectant, and citation.
Visit BTX at Immunology 2019, May 10-12, San Diego, CA, Booth #1417