Electrochemical Assay Device Microflow Separation
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Solution Overview
Problem
Existing assay devices are unable to perform assays based on the electrochemical method, which is desirable for its speed and noise resistance, particularly in bioelectronics applications.
Innovation Solution
An electrochemical assay device with an inner flow passage and a liquid absorbing material that separates the liquid into parts to be retained in the passage and absorbed by the material, featuring electrodes and conducting wires for electrochemical measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an optical detection method is used in the assay device, then the device can detect color development and chemiluminescence, but the device cannot perform electrochemical assays which are faster and more noise-resistant
Solution Approach 1:
The assay device is designed to support multiple detection methods by integrating both optical detection components (for color development and chemiluminescence) and electrochemical detection components (electrodes for amperometric or potentiometric measurements). This multi-functional design allows the same device to perform different types of assays depending on the detection method required, thereby improving adaptability while maintaining measurement reliability through appropriate method selection.
2Reliability
If a large amount of liquid is used in the assay, then the measurement can be more stable, but the device cannot achieve the portability and speed of small-scale electrochemical sensors
Solution Approach 1:
The device employs a microflow passage with specifically engineered local properties including hydrophilic/hydrophobic patterned surfaces and capillary structures that create localized liquid retention zones. These local quality modifications allow the device to hold and concentrate small volumes of liquid (nanoliter to microliter scale) in specific regions, achieving stable electrochemical measurements without requiring large liquid volumes, thus maintaining portability while improving measurement reliability.
3Productivity
If the liquid flows quickly through the passage, then the assay speed increases, but the liquid cannot be sufficiently absorbed and retained for accurate measurement
Solution Approach 1:
The device utilizes dynamic control of liquid flow through the microflow passage by adjusting the balance between capillary forces (which draw liquid forward) and gravitational forces (which can be modulated by device orientation). The hydrophilic/hydrophobic patterned surfaces create dynamic flow resistance that automatically regulates liquid velocity, allowing fast flow during sample introduction but automatic deceleration and retention during the measurement phase, thus achieving both high assay speed and sufficient liquid retention.
4Quantity of substance
If the liquid is completely absorbed by the liquid absorbing material, then no liquid remains in the passage for electrochemical measurement
Solution Approach 1:
The liquid absorption system is segmented into distinct functional zones: a microflow passage that retains a controlled volume of liquid for electrochemical measurement, and a separate liquid absorbing material positioned adjacent to but not in direct contact with the measurement zone. The hydrophilic/hydrophobic patterned surfaces create segmentation within the passage itself, with hydrophilic regions holding liquid for measurement and hydrophobic regions preventing excessive absorption. This segmentation ensures that liquid is absorbed from the sample bulk while preserving a sufficient volume in the measurement zone for accurate electrochemical detection.
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
Enables assays using a small amount of liquid with electrochemical methods, allowing for stable and efficient measurements.
Implementation Method 1
a separating flow passage that is provided between the microflow passage and the liquid absorbing material for separating the liquid inside the inner flow passage into a part to be left in the microflow passage and a part to be absorbed by the liquid absorbing material
Implementation Method 2
perform an assay based on the electrochemical method... an electrode portion disposed inside the microflow passage
Data Source
AI summary
An electrochemical assay device includes an inner flow passage through which a liquid injected from an inlet flows and a first liquid absorbing material that absorbs the liquid that has passed through the inner flow passage, and is configured to be able to perform an assay based on an electrochemical method. The inner flow passage includes a microflow passage that communicates with the inlet and a separating flow passage provided between the microflow passage and the first liquid absorbing material for separating the liquid inside the inner flow passage into a part to be left in the microflow passage and a part to be absorbed by the first liquid absorbing material when the injection of the liquid is stopped. The electrochemical assay device includes an electrode portion that is disposed inside the microflow passage, a connecting portion that is connected to an external measurement device, and a conducting wire portion that electrically connects the electrode portion to the connecting portion.