Design of a Cole-Cole Meter for Complex Impedance Measurement of Living Tissues

H. Solmaz, Y. Ülgen, and M. Tümer (Turkey)


Cole-Cole parameters, bioimpedance, magnitude-ratio andphase-difference detection.


Measurement of complex impedance of biological systems is gaining wide popularity in determining the pathological and physiological status of tissues in research areas such as; body fat content, blood freshness, tissue ischemia, skin hydration, and etc. In this paper, we designed a four probe, multi-frequency impedance meter for quick assessment of the viability of erythrocyte suspensions under storage conditions. Impedance measurements are based on magnitude-ratio and phase-difference detection principles. The system is built around a sine-wave generator, a voltage controlled current source, a phase gain detector and a microcontroller unit. Device accuracy is checked against the HP 4284A LCR meter under different RC test loads that simulate physiological measurements. As a novelty, Cole-Cole parameters namely R0, R, fc, α and the extracellular fluid and intracellular fluid resistances, Re and Ri are directly displayed in the same device, for the ease of use.

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