Cell Permittivity Measurement via Synchronized Sampling
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Solution Overview
Problem
Existing impedance spectroscopy methods for determining the permittivity of cell populations suffer from low measurement accuracy and significant fluctuations over a wide frequency range, leading to unreliable results.
Innovation Solution
A method involving the generation of an excitation current oscillating at a defined frequency, simultaneous measurement and sampling of voltage between electrodes, and digital signal processing to determine permittivity, minimizing interference and ensuring high sampling accuracy through synchronized sampling and appropriate sampling rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog signal processing is used to determine characteristic properties of the cell population, then real-time measurement is achieved, but measurement accuracy decreases and interference effects increase
Solution Approach 1:
The patent applies preliminary action by performing analog-to-digital conversion of both the excitation current and voltage signals before any processing occurs. This early digitization captures the complete signal information without loss, allowing subsequent digital processing to achieve high measurement accuracy without the interference problems that plague analog processing chains.
Solution Approach 2:
The patent substitutes the mechanical/analog signal processing system with a digital processing system. Instead of using analog amplifiers, filters, and processors that are susceptible to interference and drift, the invention uses digital signal processing algorithms to determine characteristic properties, thereby eliminating the harmful effects of analog processing while maintaining measurement capabilities.
2Measurement precision
If sampling rate is increased to improve measurement accuracy, then determination precision improves, but data processing requirements and complexity increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the sampling rate based on the excitation frequency. The sampling rate is set to a multiple of the excitation frequency, which provides sufficient resolution for accurate measurement while avoiding unnecessarily high sampling rates that would generate excessive data and burden processing systems. This adaptive parameter adjustment optimizes both precision and processing efficiency.
3Adaptability or versatility
If measurement range is expanded to cover wide frequency range, then versatility improves, but measurement reliability decreases due to fluctuations
Solution Approach 1:
The patent applies dynamics by making the sampling rate adaptive to the excitation frequency. Rather than using a fixed sampling rate that may be insufficient at certain frequencies, the system dynamically adjusts the sampling rate to be a multiple of the current excitation frequency, ensuring consistent measurement quality and reliability across the entire frequency range from 10 Hz to 10 MHz.
Solution Approach 2:
The patent implements feedback by using the determined characteristic properties to provide information about the measurement quality. The system monitors the measurement results and can adjust parameters based on the quality indicators, ensuring reliable measurements across the wide frequency range by compensating for any degradation in measurement conditions.
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 approach enables highly accurate determination of permittivity values over a wide frequency range, reducing interference and providing reliable measurements by converting analog signals to digital for precise analysis without real-time constraints.
Implementation Method 1
Electrical impedance spectroscopy methods are used as measurement methods for the nondestructive in-situ and in-vivo determination of frequency-dependent passive electrical properties of biological materials
Implementation Method 2
determining a value indicative of the permittivity of the cell population... The above-mentioned frequency-dependent passive electrical properties of the cell population can, inter alia, provide information about the number of living cells and/or the size of the cells and/or the homogeneity of the cells
Data Source
AI summary
A method for determining a value indicative of the permittivity of a cell population in the context of impedance spectroscopy comprises the following steps: generating an excitation current through the cell population, which oscillates with an excitation frequency; measuring a voltage in the cell population between a first measuring electrode (12) and a second measuring electrode (14); sampling the excitation current, wherein first sampled values for the excitation current are generated; sampling the voltage between the first measuring electrode (12) and the second measuring electrode (14), wherein second sampled values for the voltage between the first measuring electrode and the second measuring electrode are generated; and determining the value indicative of the permittivity of the cell population on the basis of the first sampled values and the second sampled values.