Confirmation of membrane electroporation from flicker noise

Living systems interact with their environment through biological membranes . Charge movement across these membranes plays a key role in several natura l processes and has been the subject of intense research. Charge can transp ort through the hydrophobic barrier of the membrane by means of ion channel s, ionophores or electric-field-induced pores. Membrane electroporation res ults in a nonlinear I-V characteristic of the system. However, nonlinear be havior is exhibited, by the majority of the inhomogeneous systems and hence is not a definite proof of pore formation. Noise measurement is a well acc epted method of studying the charge transport in inhomogeneous systems and we report here our study of the noise spectral density in a planar lipid me mbrane, which is a model for more complex biological membranes to study the molecular processes involved in transmembrane charge conduction. Analysis of our results, in the light of similar experiments conducted in various in homogeneous systems, confirms that nonlinearity here is the signature of me mbrane electroporation.