Curved Electrodes for Microfluidic Impedance Sensing

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Solution Overview

Problem

Existing microfluidic devices with flat electrodes for electrical impedance measurements suffer from low sensitivity and signal-to-noise ratio due to non-homogeneous electric fields and position-dependent signal quality, hindering reliable detection and characterization of analytes.

Innovation Solution

A microfluidic device with a fluid channel and a pair of electrodes having three-dimensionally structured, curved surfaces that envelop the longitudinal channel axis, enhancing sensitivity and signal-to-noise ratio by providing better sensing coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If flat electrodes are placed at the bottom or top and bottom sides of the microfluidic channel, then the device structure is simple, but the sensitivity and signal-to-noise ratio are low due to non-homogeneous electric fields and position-dependent signal quality

Engineering Contradiction:

Improveelectrode structure simplicityVSAvoiddetection sensitivity and signal-to-noise ratio

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies curvature to the electrode surfaces by wrapping them around the microfluidic channel in a concentric arrangement. This curved configuration creates a more homogeneous electric field distribution across the fluid channel cross-section, improving detection sensitivity and signal-to-noise ratio while maintaining manufacturing feasibility through standard thin-film fabrication techniques adapted to curved geometries

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent transitions from two-dimensional flat electrode surfaces to three-dimensional curved electrode surfaces that wrap around the channel. This dimensional change allows the electrodes to envelop the fluid channel more completely, providing uniform electric field coverage and consistent signal quality regardless of analyte position within the channel

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If flat electrodes are used, then the manufacturing process is straightforward, but the electric field is non-homogeneous causing signal quality to depend on particle position in the channel

Engineering Contradiction:

Improveelectrode fabrication simplicityVSAvoidelectric field homogeneity and signal consistency

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The curved electrode surfaces wrapped around the channel create a radially symmetric electric field distribution that is homogeneous across the fluid channel. This curvature ensures that the electric field lines are uniformly distributed perpendicular to the channel axis, making the detection signal independent of the analyte's lateral position within the channel

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The concentric curved electrode configuration produces a homogeneous electric field within the fluid channel by ensuring uniform electrode spacing and surface area distribution around the channel perimeter. This homogeneity guarantees consistent electrical impedance measurements regardless of where the analyte passes through the sensing region

Inventive Principle:

Principle #33Homogeneity

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

The device achieves higher sensitivity and improved signal-to-noise ratio, enabling reliable detection and characterization of analytes, and can be used as a flow cytometer or hematology analyzer for blood cell classification and counting.

Implementation Method 1

Existing microfluidic devices that employ thin-film electrodes for electrical impedance measurements for analyte (particle or cell) differentiation

Methodology Applied

Scientific EffectElectrical impedance: Electrical Resistance

Implementation Method 2

an optic sensing unit structured to optically sense a sensing region of the fluid channel between the at least one pair of electrodes

Methodology Applied

Scientific EffectOptical sensing: Light

Data Source

PatentUS20250102414A1A microfluidic device for detecting and characterizing at least one analyte, for example a cell, in a sample fluid

Publication Date: 2025.03.27 TECH UNIV EINDHOVEN

AI summary

A device for detecting at least one analyte, for example a cell, in a sample fluid, the device comprising a fluid channel having a longitudinal channel axis and structured to allow the sample fluid containing at least one analyte to pass through the fluid channel, at least one pair of electrodes, an electric field generating unit for generating an electric field between the at least one pair of electrodes, a detecting unit for detecting the at least one analyte in the sample fluid based on its passage through the electric field, wherein each electrode of the at least one pair of electrodes has a three-dimensionally structured electrode surface, which electrode surface is curved about the longitudinal channel axis. The device may further comprise an optic sensing unit structured to optically sense a sensing region of the fluid channel between the at least one pair of electrodes.