Dielectric sensing for sample characterization
Inventors
Suster, Michael • Mohseni, Pedram • Maji, Debnath • Stavrou, Evi • Gurkan, Umut
Assignees
Case Western Reserve University • US Department of Veterans Affairs
Publication Number
US-10674931-B2
Publication Date
2020-06-09
Expiration Date
2037-01-17
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Abstract
As one example, a fluid monitoring apparatus includes a dielectric microsensor that includes a capacitive sensing structure integrated into a microfluidic channel. The microfluidic channel includes a fluid input to receive a sample volume of a sample under test (SUT). A transmitter provides an input radio frequency (RF) signal to an RF input of the microsensor. A receiver receives an output RF signal from the microsensor. A computing device computes dielectric permittivity values of the SUT that vary over a time interval based on the output RF signal. The computing device may determine at least one permittivity parameter based on the computed dielectric permittivity values over at least a portion of the time interval.
Core Innovation
This disclosure relates to a sensor system, methods of making a sensor, and methods of using a sensor to determine properties of a sample through dielectric sensing. The invention provides a fluid monitoring apparatus including a dielectric microsensor with a capacitive sensing structure integrated into a microfluidic channel, which receives a sample volume of a sample under test (SUT). The system uses a transmitter to provide an input radio frequency (RF) signal to the microsensor and a receiver to receive an output RF signal from it. A computing device computes dielectric permittivity values of the SUT varying over time from the output RF signal and determines at least one permittivity parameter based on these values over a measurement interval.
The invention addresses the problem of typical dielectric spectroscopy (DS) systems being large and expensive, which makes them cost-prohibitive in certain circumstances. Existing DS techniques are powerful for monitoring and analysis in fields such as petroleum, agriculture, food safety, pharmaceuticals, and biomedical applications, but their size and cost limit practical use, especially for point-of-care or other portable needs.
The disclosed approach integrates a dielectric microsensor into a portable apparatus, such as a handheld or desktop unit, allowing measurement of impedance characteristics of a fluid or gas SUT within a microfluidic channel. The time-based dielectric permittivity values are analyzed to determine permittivity parameters like time to peak dielectric permittivity, difference between peak and plateau permittivity, and rate of change, which correlate to properties of the SUT. This modular, potentially disposable sensing approach facilitates rapid, low-cost DS measurements suitable for sensitive applications such as blood analysis, including anticoagulation and platelet function monitoring at point of care.
Claims Coverage
The patent includes three independent claims covering an apparatus, a system, and a method related to dielectric permittivity sensing using a dielectric microsensor integrated into a microfluidic channel.
Fluid monitoring apparatus with dielectric microsensor integrated into microfluidic channel
A fluid monitoring apparatus comprising a dielectric microsensor with a capacitive sensing structure integrated into a microfluidic channel to receive a sample volume of a sample under test (SUT). The apparatus includes a transmitter to provide an input radio frequency (RF) signal to the microsensor and a receiver to receive an output RF signal. A computing device computes dielectric permittivity values over a time interval from the output RF signal and determines at least one permittivity parameter based on evaluating these values.
System with sensor interface and computing device for time-based dielectric permittivity measurement
A system comprising a sensor interface electrically connected to a sensing apparatus. The sensor interface includes a transmitter to provide an input RF signal and a receiver to receive an output RF signal indicative of dielectric permittivity of the SUT. A computing device computes dielectric permittivity values varying over a time interval and determines at least one permittivity parameter based on these values.
Method for measuring dielectric permittivity and analyzing permittivity parameters for a sample under test
A method comprising providing an input RF signal to a dielectric microsensor, receiving an output RF signal representing impedance of a sample under test within the microsensor, calculating dielectric permittivity values varying over a measurement time interval based on the output RF signal, and analyzing these values over at least a portion of the interval to determine at least one permittivity parameter.
The claims collectively cover the innovative integration of a dielectric microsensor into a microfluidic channel with RF excitation and detection, computing dielectric permittivity values over time, and analyzing those values to determine parameters indicative of sample properties. The apparatus, system, and method focus on time-dependent permittivity analysis with modular and portable configurations, particularly useful for biological sample characterization.
Stated Advantages
Provides a low-power, low-cost, portable instrument for rapid extraction of molecular and cellular properties of samples using microliter sample volumes.
Enables rapid, high-throughput, and comprehensive diagnosis of platelet and coagulation defects at the point of care.
Offers high resolution in permittivity measurements allowing sensitive detection of hemostatic defects including both platelet and coagulation factor components.
Allows modular, disposable sensor use, avoiding contamination and enabling repeated measurements with replaceable sensors.
Can be implemented as handheld or benchtop devices with user interfaces and communication modules for remote data analysis and alerts.
Documented Applications
Chemical analysis of oil in the petroleum industry.
Security or defense substance analysis.
Soil moisture monitoring in agriculture.
Fermentation monitoring during alcoholic beverage production.
Food quality and safety monitoring.
Drug development in the pharmaceutical industry.
Biomedical analytical tool for label-free, non-destructive, real-time study of biological and biochemical samples including human blood, spinal fluid, breast tissue, and skin.
Indication of anticoagulation properties of blood samples and assessment of anticoagulation therapy effectiveness, including target-specific oral anticoagulants.
Assessment of platelet function in blood samples.
Rapid and comprehensive diagnosis of platelet and coagulation defects.
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