Changes in hydration of liposome membranes exposed to nanosecond electric pulses detected by wide-field Coherent anti-Stokes Raman microspectroscopy

Electropulsation has become a powerful technological platform for electromanipulation of cells and tissues for various medical and biotechnological applications, but the molecular changes that underlay the very first initiation step of this process have not been experimentally observed.Here, we endowed a wide-field Coherent anti-Stokes Raman Scattering platform with an ad-hoc electromag-netic exposure device and we demonstrated, using artificial lipid vesicles (i.e. liposomes), that electropulsation is initiated by the increase of interstitial water content in liposome membranes. A pulse-dependent accumulation of the interstitial water molecules is observed in the membranes and a plausible mechanism supported by a computational electrochemical model is presented and discussed.