Eur. Phys. J. E 2, 161-168
Noise measurements in bilayer lipid membranes during electroporation
A. Ridi1 - E. Scalas2 - A. Gliozzi1
1 Istituto Nazionale per la Fisica della Materia and
Dipartimento di Fisica, Università di Genova, Via Dodecaneso
33, 16146, Genova, Italy
2 Dipartimento di Scienze e
Tecnologie Avanzate, Universtià del Piemonte Orientale, Corso
Borsalino 54, 15100, Alessandria, Italy
gliozzi@fisica.unige.it
Received 1 June 1999 and Received in final form 1 October 1999
Abstract
A study of voltage fluctuations in bilayer lipid
membranes during electroporation and under current-clamp
conditions is presented. Qualitative considerations based on the
electroporation theory are used in order to explain the phenomenon
on long time scale. Indeed, the current-clamp condition induces a
feedback mechanism on the pore formation and therefore on the
macroscopic conductance. Voltage fluctuations can thus be
recorded. These fluctuations are nonstationary long-living and
have a flicker power spectrum over nearly four decades of
frequency between about 10-2 and 102 Hz. The study
of the fluctuations in the time domain has been performed by
introducing an electrical model of the system formed by the
membrane and the circuit under current-clamp configuration. The
analysis of the time series gives a characteristic time of
100 ms for the circuitry response to the fragments of
electroporation signals with characteristic times faster than
100 ms. During electroporation, the response to an external
periodic stimulus in the frequency range 10-1-10 Hz
shows that the system behaves linearly, even if voltage
fluctuations are present.
PACS
87.16.Dg Membranes, bilayers, and vesicles -
87.68.+z Biomaterials and biological interfaces -
87.15.Ya Fluctuations
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag
