NON LINEAR DIELECTRIC PROPERTIES OF MICROBIOLOGICAL SUSPENSIONS AT ELECTRODE-ELECTROLYTE INTERFACES

TREO, ERNESTO F.; FELICE, CARMELO J.; MADRID, ROSSANA E.

Shangai

Conferencia; 27th Annual International Conference of the IEEE, EMBS and XV Congreso Argentino de Bioingeniería; 2005

IEEE- EMBS

Nonlinear properties of biological suspensions have been previously presented as a bulk phenomenon, however, some authors consider that they are generated at the electrode-electrolyte interface and are reflected as a bulk property phe-nomenon. They were mainly ascribed to the H+–ATPase pre-sent in the plasma membrane of these cells. In this paper, we describe the construction of a dual-cell nonlinear dielectric spectrometer. The system is applied to the study of interfaces with resting cell suspensions of Saccharomyces cerevisiae. Sub-stantial harmonics are generated at the interface when a sinu-soidal current is applied and altered by the presence of yeast. When a second interface with yeast and enzyme inhibitor is used as reference, a decrease in the magnitude response of the third harmonic can be observed. As it was already described for the solution bulk, we obtained a similar behavior at the interface. Besides, we also found optimal intervals, respec-tively, for frequency and voltage to reach maximal response. This result would support the contention that biological nonlinearity is an interface-based phenomenon.