1.D.21 The Lipid Nanopore (LipNP) Family

Cell permeabilization by electric pulses (EPs), or electroporation, has been well established as a tool to indiscriminately increase membrane flows of water solutes down the concentration and voltage gradients. Pakhomov et al., 2009 found that EPs of nanosecond duration (nsEPs) trigger formation of voltage-sensitive and inward-rectifying membrane pores. NsEP-treated cells remained mostly impermeable to propidium, suggesting that the maximum pore size is approximately 1nm. The ion-channel-like properties of nsEP-opened nanopores vanish if they break into larger, propidium-permeable 'conventional' pores. However, nanopores can be stable for many minutes and significantly impact cell electrolyte and water balance. Multiple nsEPs cause fast cell swelling and blebbing. The lipid nature of nsEP-opened nanopores was confirmed by fast externalization of phosphatidylserine residues. Nanopores constitute a previously unexplored ion transport pathway that supplements classic ion channels but is distinctly different from them (Pakhomov et al., 2009).

The reaction catalyzed by lipid nanopores is:

ions (out) ⇌ ions (in)

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