The Pulse Intensity - duration dependency for Cell Membrane Electroporation

External electric field, which is applied to cells, can, under suitable field parameters, induce local distortions and structural rearrangements of lipid molecules in the cell membrane. Depending on the field parameters, the membrane hence becomes either transiently or permanently permeable even after the field has ceased, allowing molecules that are otherwise deprived of transport mechanisms to cross the membrane and reach the cytosol. This phenomenon is often referred to as electroporation or electropermeabilization. The method is today successfully used in different applications, such as the introduction of molecules into cells (Rols and Teissié 1998, Neumann et al. 1999, Canatella et al. 2001, Maček Lebar and Miklavčič 2001), transdermal drug delivery (Prausnitz 1996, Denet et al. 2004, Pavšelj and Préat 2005), fusion of cells (Zimmerman 1982, Ogura et al. 1994, Ušaj et al. 2009), electroinsertion of proteins into membranes (Elouagari et al. 1995, Teissié 1998), sterilization (Knorr 1999, Rowan et al. 2000, Teissié et al. 2002, El Zakhem et al. 2007), and tissue ablation (Davalos et al. 2005, Lavee et al. 2007). The main clinical success of electroporation was achieved in the treatment of cutaneous and subcutaneous tumors, where chemotherapeutic drugs in combination with electric pulses were delivered to tumor cells (electrochemotherapy) (Heller et al. 1999, Mir and Orlowski 1999, Marty et al. 2006, Serša et al. 2008), while another application, a nonviral delivery of nucleic acids to cells (gene electrotransfection), is also gaining increasing interest (Jaroszeski et al. 1999, Šatkauskas et al. 2002, Golzio et al. 2007). 12