Cell Evaluation Device Electrode Positioning for Resistance Measurement
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Solution Overview
Problem
The existing cell evaluation devices face difficulties in accurately measuring the increase in electric resistance due to the formation of tight junctions among cells, as the electric resistance measurements include resistances from passages and wiring, making it challenging to determine the point of sufficient tight junction formation.
Innovation Solution
A cell evaluation device configuration with electrodes positioned across specific areas on the porous membrane, allowing only the electric resistance of the cells to be measured, reducing the influence of passage and wiring resistances, and utilizing a four-terminal method to accurately measure the change in resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electrodes are provided at the inlet of the first passage member and at the outlet of the second passage member, then the device structure is simplified, but the measurement precision deteriorates because the electric resistance measurement includes resistance from passages and wiring in addition to cell resistance
Solution Approach 1:
The passage members are divided into multiple sections with electrodes strategically positioned at specific locations. The first passage member has a first section with a first electrode and a second section with a second electrode, allowing segmentation of the measurement path to exclude passage resistance from the cell resistance measurement.
Solution Approach 2:
The measurement system extracts only the cell resistance component by positioning electrodes to contact cells directly on the porous membrane surface, separating the cell resistance measurement from the passage resistance. This extraction allows accurate measurement of tight junction formation without interference from passage and wiring resistance.
2Measurement precision
If electrodes are positioned to measure only cell resistance, then the measurement precision improves, but the device complexity increases due to specific electrode positioning requirements
Solution Approach 1:
The electrode structures are merged with the passage member bodies, with electrodes integrated into the passage walls or bases. This combining approach achieves precise electrode positioning for accurate cell resistance measurement while maintaining structural simplicity through integration rather than separate components.
Solution Approach 2:
The passage members serve multiple functions: they guide culture solution flow, provide structural support, and incorporate electrodes for measurement. This multi-functionality reduces the need for separate measurement components, simplifying the overall device structure while maintaining high measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables easy and accurate measurement of the increase in electric resistance due to tight junction formation, allowing for precise determination of when sufficient tight junctions are formed among cells, enhancing the evaluation process.
Implementation Method 1
cells are cultivated on the porous membrane
Implementation Method 2
The electric resistance thus measured includes electric resistance of the porous membrane and electric resistance of the cells
Data Source
AI summary
A cell evaluation device includes: a porous membrane having a first main face and a second main face; a first passage having a first passage portion facing a first area on which cells are placed in the first main face of the porous membrane; a second passage having a second passage portion facing a second area in the second main face of the porous membrane, the second area being positioned backside of the first area; and a first electrode provided in the first passage portion and a second electrode provided in the second passage portion, the first electrode and the second electrode being positioned across the first area and the second area. In the cell evaluation device, tight junctions are formed among the cells by cell cultivation. With the cell evaluation device, any increase in the electric resistance occurring due to the formation of the tight junctions can be easily measured.