Magnetic Particle Transport in Segmented Fluidic Devices

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Solution Overview

Problem

Conventional immunoassays require time-consuming and labor-intensive washing steps to remove unreacted chemicals, limiting their use in rapid, point-of-care applications due to increased complexity and cost, and existing methods lack accuracy and simplicity for hand-held, point-of-use testing.

Innovation Solution

A system and method using magnetic particles with attached binding agents that are moved through different regions of a device by an external magnet, eliminating the need for washing by using gaseous separations and magnetic forces to separate fluid compartments, allowing for rapid and quantitative analyte detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If washing steps are performed to remove unreacted chemicals, then sensitivity and accuracy of detection are improved, but time consumption and operational complexity increase

Engineering Contradiction:

Improvedetection sensitivityVSAvoidtesting time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The invention extracts the unreacted chemicals from the reaction system by using magnetic particles to bind and separate the antibody-analyte complexes from the solution. This extraction eliminates the need for traditional washing steps while maintaining detection sensitivity, as the magnetic separation effectively removes unreacted chemicals without requiring time-consuming manual washing procedures.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical washing process with a magnetic field-based separation system. Instead of using mechanical agitation and manual washing steps, the system uses an external magnet to generate magnetic fields that move magnetic particles through different fluid environments, achieving chemical separation without mechanical intervention and significantly reducing testing time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If washing steps are performed to remove unreacted chemicals, then detection accuracy is improved, but device complexity and automation cost increase

Engineering Contradiction:

Improvedetection accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The magnetic particles serve multiple functions: they act as binding carriers for antibodies, enable separation of complexes from solution, and facilitate movement through different fluid environments via magnetic field control. This multi-functionality eliminates the need for separate washing mechanisms, reducing device complexity while maintaining detection accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The magnetic particles act as intermediaries between the antibody-analyte complexes and the external magnetic field. These particles enable controlled movement and separation without requiring complex mechanical washing systems, simplifying the overall device architecture while achieving effective removal of unreacted chemicals for accurate detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of substance

If magnetic particles are moved through gaseous separations, then washing efficiency is improved, but fluidic system complexity increases

Engineering Contradiction:

Improveunreacted chemical removalVSAvoidfluidic compartment separation

Core Design Contradiction:

Loss of substanceVSDevice complexity

Solution Approach 1:

The fluidic system is segmented into discrete compartments separated by gaseous barriers. Each compartment contains specific reagents or solutions, and magnetic particles are moved sequentially through these segmented regions. This segmentation enables efficient washing and separation functions while maintaining a relatively simple overall device structure, as the gaseous separations naturally prevent mixing between compartments.

Inventive Principle:

Principle #1Segmentation

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 rapid, accurate, and cost-effective point-of-care testing by eliminating the need for washing steps, improving sensitivity and reducing operational complexity, while maintaining quantitative results.

Implementation Method 1

magnetic particles with attached binding agents that are moved through different regions of a device by an external magnet

Methodology Applied

Scientific EffectMagnetic force: Magnetism

Implementation Method 2

fluidic compartments separated by gaseous separations

Methodology Applied

Scientific EffectGas-liquid separation:

Data Source

PatentUS9528985B2Discontinuous fluidic systems for point-of-care analyte measurement

Publication Date: 2016.12.27 FANNIN PARTNERS LLC

AI summary

Disclosed herein are systems and methods for using the controlled movement of magnetic particles using controlled magnetic fields in a fluidic device containing separated fluidic regions to detect analytes in solution by immunoassay, such as an enzyme-linked immunosorbant assay (ELISA) for various medical and scientific applications. In order to achieve sequential exposure to the different chemical environments required in an immunoassay, magnetic particles are driven through fluid-containing chambers separated by air-gaps that may take the form of air bubbles or small open-air separations, for example. Externally controlled magnets coupled to actuators draw the flow of magnetic particles through air-liquid interfaces produced by microfluidic surface tension at the air-gap, washing the particles.