Obtain better electroporation results by understanding the electroporation pulse
Electroporators often have multiple electrical wave form pulse settings such as exponential decay, time constant and square wave. Every cell type has a unique optimal Field Strength (E) that is dependent on the pulse parameters applied; i.e. voltage, capacitance and resistance. Application of optimal field strength causes electropermeabilization through induction of transmembrane voltage, which allows nucleic acids to pass through the cell membrane (1).
Three different types of pulses are used for electroporation of nucleic acids:
- Exponential Decay Pulse: In this type of pulse, the set voltage is released from the capacitor and decays rapidly and exponentially over time (millisecs). The delivered pulse is characterized by two parameters: the field strength (kV/cm) and the time constant. These parameters can be adjusted by varying voltage and capacitance settings to achieve a wide pulse gradient. The pulse is easily titrated to achieve very good transfection efficiency in most cell types.
- Square Wave Pulse: This wave pulse is characterized by the voltage delivered, the duration of the pulse, the number of pulses and the length of the interval between pulses. All of these parameters can be set using many conventional electroporators.
- Time Constant: A constant pulse is applied for a set period of time at a set voltage.