Lateral Flow Electrode Inversion for Bubble-Free Detection

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Solution Overview

Problem

Lateral flow assays suffer from low sensitivity, multiplexity, and quantifiability issues due to air bubbles forming above electrodes, which impede reliable electrical detection of liquid samples.

Innovation Solution

The arrangement features electrically conductive electrodes on the front side of an insulating carrier in direct contact with a membrane, preventing air bubbles and enabling direct contact with liquid samples, allowing for multiplex and sensitive electrical detection. The membrane, such as nitrocellulose, facilitates lateral liquid transport and good wetting of electrodes, while the carrier's design ensures electrical connectivity without short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrodes are arranged below the membrane with insulator layers (prior art configuration), then electrical insulation is provided, but air bubbles form in cavities above electrodes leading to measurement failure

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidelectrode arrangement complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional electrode arrangement by placing electrodes on the front side of the carrier above the membrane rather than below it. This inversion eliminates the cavity formation that traps air bubbles, allowing liquid to flow directly over the electrodes without air inclusions that would interfere with measurements.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent removes the insulator layer that was previously placed between the electrode and membrane in the conventional configuration. By extracting this insulator layer, the design achieves direct contact between the electrode and liquid sample through the membrane, eliminating the cavity where air bubbles would form while maintaining electrical insulation through the membrane itself.

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If optical, magnetic and electrical methods are used to achieve good quantifiability, then measurement precision is improved, but multiplexity remains very low

Engineering Contradiction:

ImprovequantifiabilityVSAvoidmultiplexity

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent divides the measurement system into multiple spatially separated measurement points on the membrane surface, each with its own electrode. This segmentation allows simultaneous measurement at multiple locations (multiplexity) while maintaining the electrical detection method's inherent precision and quantifiability for each individual measurement point.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-point measurement to multi-point measurement by utilizing the two-dimensional surface of the membrane. Multiple electrodes can be arranged in arrays across the membrane surface, enabling simultaneous measurements at multiple spatial locations while maintaining the precision of electrical detection methods.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If lateral flow assay is used for simplicity and cost-effectiveness, then ease of operation is improved, but sensitivity and quantifiability are low

Engineering Contradiction:

Improvehandling simplicityVSAvoidsensitivity

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces optical or magnetic detection methods with electrical detection methods. Electrical methods inherently provide higher sensitivity and quantifiability while maintaining the simplicity of lateral flow operation, as the electrical signals can be precisely measured and quantified without complex optical systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from optical/magnetic signals to electrical signals. This parameter change enables higher sensitivity and better quantifiability while preserving the ease of operation characteristic of lateral flow assays, as electrical measurements can be performed with simple, integrated electrodes.

Inventive Principle:

Principle #35Parameter changes

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 reliable, spatially resolved electrochemical measurements with high sensitivity and quantifiability, preventing air inclusions and allowing for simultaneous multiplex measurements without interference.

Implementation Method 1

The membrane, such as nitrocellulose, facilitates lateral liquid transport and good wetting of electrodes

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

electrically conductive electrodes are formed on the first carrier... enabling direct contact with the liquid sample, allowing for multiplex and sensitive electrical detection

Methodology Applied

Scientific EffectElectrochemical detection:

Data Source

PatentUS10514353B2Arrangement and method for the electrochemical analysis of liquid samples by means of lateral flow assays

Publication Date: 2019.12.24 SIEMENS AG

AI summary

An arrangement and to a method are provided for the electrical detection of liquid samples by lateral flow assays. The lateral flow assay includes a membrane arranged on a front side of a first carrier. The first carrier is electrically insulating. On the front side of the first carrier between the carrier and the membrane, electrically conductive electrodes are arranged in direct contact with the membrane.