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Marking 100 years since Rudolf Höber’s discovery of the insulating envelope surrounding cells and of the β-dispersion exhibited by tissue

Ronald Pethig
Ronald Pethig
 und 
Ilka Schmueser
Ilka Schmueser
   | 23. Nov. 2012
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Article Category: Tutorial Article
Online veröffentlicht: 23. Nov. 2012
Seitenbereich: 74 - 79
Eingereicht: 07. Sept. 2012
DOI: https://doi.org/10.5617/jeb.401
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© 2012 Ronald Pethig and Ilka Schmueser, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Figure 1

A schematic of the β-dispersion exhibited by fresh tissues and compacted viable cells (derived from Schwan [4]). As the frequency is increased from ~1 kHz to 100 MHz, this dispersion is characterised by about a five-fold increase of conductivity, and around three orders of magnitude decrease of permittivity ε.
A schematic of the β-dispersion exhibited by fresh tissues and compacted viable cells (derived from Schwan [4]). As the frequency is increased from ~1 kHz to 100 MHz, this dispersion is characterised by about a five-fold increase of conductivity, and around three orders of magnitude decrease of permittivity ε.

Figure 2

Based on Höber’s original drawing [1] his signal generator consisted of an induction coil connected to a spark gap. The frequency of the induced transient oscillating current in the external circuit was determined by the capacitance C of a glass plate and the inductance of a coil wound onto a gas lamp. The conductivity of a trough (trog) of vials to mimic a cell sample, or of a sample of compacted red blood cells, was determined by comparing the damping of the oscillating current due to ion conduction against that of a series of NaCl solutions. Different forms of detector were tested to optimise the determination of the damping effect.
Based on Höber’s original drawing [1] his signal generator consisted of an induction coil connected to a spark gap. The frequency of the induced transient oscillating current in the external circuit was determined by the capacitance C of a glass plate and the inductance of a coil wound onto a gas lamp. The conductivity of a trough (trog) of vials to mimic a cell sample, or of a sample of compacted red blood cells, was determined by comparing the damping of the oscillating current due to ion conduction against that of a series of NaCl solutions. Different forms of detector were tested to optimise the determination of the damping effect.

Figure 3

Equivalent circuits proposed for: (a) tissues and compacted red blood cells by Philippson [20]. R and r are attributed to the cytoplasm and membrane resistance, respectively, and C to the membrane capacitance; (b) red blood cell suspensions proposed by Fricke & Morse [5], in which R0 is the resistance to current flow around the cell, and Ri is the cytoplasm resistance; (c) the squid giant axon by Cole & Baker to account for their discovery of the inductive reactance [26]. The values for R, C and L were determined as 1 kΩ cm2, 1 μF/cm2 and 0.2 H cm2, respectively.
Equivalent circuits proposed for: (a) tissues and compacted red blood cells by Philippson [20]. R and r are attributed to the cytoplasm and membrane resistance, respectively, and C to the membrane capacitance; (b) red blood cell suspensions proposed by Fricke & Morse [5], in which R0 is the resistance to current flow around the cell, and Ri is the cytoplasm resistance; (c) the squid giant axon by Cole & Baker to account for their discovery of the inductive reactance [26]. The values for R, C and L were determined as 1 kΩ cm2, 1 μF/cm2 and 0.2 H cm2, respectively.

Rudolf Höber, ca. 1950. (Reproduced with permission of the American Philosophical Society.)
Rudolf Höber, ca. 1950. (Reproduced with permission of the American Philosophical Society.)
eISSN:
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Technik, Bioingenieurwesen, Biomedizinische Elektronik, Biologie, Biophysik, Medizin, Biomedizinische Technik, Physik, Spektroskopie und Metrologie
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