Biosensor Magnet Assembly for Magnetic Particle Actuation

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Solution Overview

Problem

Existing biosensor systems using magnetic labels face challenges in efficiently controlling the movement of magnetic particles, leading to unreliable test results due to unbound particles interfering with bound particles near the sensor surface, requiring complex mechanical structures and limited directional control.

Innovation Solution

A biosensor system with a biosensor cartridge and a first biosensor magnet assembly featuring two magnetic subunits and a second magnet assembly above the sensor surface, allowing for flexible control of magnetic particle movement in multiple directions, including horizontal and vertical, using controllable magnetic fields to direct particles to the sensor surface and prevent unbound particles from interfering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two magnets are arranged on opposite sides of the sensor cartridge with mechanical movement, then magnetic particles can be actuated toward the sensor surface, but the system becomes complex and time-consuming

Engineering Contradiction:
Improvetest result reliabilityVSAvoidholding structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical movement system with an electromagnetic field system. Instead of physically moving magnets through a holding structure, the invention uses controllable electromagnetic fields generated by coil assemblies to actuate magnetic particles. The coil assemblies can be independently controlled to create magnetic fields that move particles in both vertical and horizontal directions, eliminating the need for complex mechanical positioning mechanisms while achieving the same particle manipulation goals.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements dynamic control of magnetic fields through independently controllable coil assemblies. The magnetic field strength and direction can be dynamically adjusted by controlling the current in each coil assembly, allowing flexible particle manipulation without mechanical movement. This dynamic electromagnetic control replaces the static mechanical holding structure, enabling rapid and precise particle actuation.

Inventive Principle:
Principle #15Dynamics

2Speed

If only vertical magnetic field is applied, then particles move perpendicular to sensor surface, but horizontal distribution of particles remains uncontrolled

Engineering Contradiction:
Improveparticle movement speedVSAvoiddirectional control flexibility
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The patent extends the magnetic field control from one dimension (vertical) to two dimensions by adding horizontal field control capability. The coil assemblies are arranged and controlled to generate magnetic field components in both vertical and horizontal directions. This allows particles to be actuated not only toward the sensor surface but also distributed horizontally across the sensor area, enabling comprehensive two-dimensional particle manipulation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If unbound magnetic particles are not removed, then they remain in the cartridge, but they interfere with the quantity measurement of bound particles

Engineering Contradiction:
Improveanalytical procedure speedVSAvoidanalyte quantity measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent extracts or removes unbound magnetic particles from the sensor measurement area using controlled magnetic fields. The coil assemblies generate magnetic field gradients that selectively actuate unbound particles away from the sensor surface while leaving bound particles undisturbed. This extraction of interfering unbound particles ensures that subsequent measurements only detect bound particles, improving measurement accuracy without requiring physical removal of the cartridge.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution enables more reliable test results by ensuring equal distribution of particles and preventing unbound particles from reaching the sensor surface, improving the accuracy of analyte detection and quantity measurement.

Implementation Method 1

a first biosensor magnet assembly with two magnetic subunits 20a, 20b for generating a magnetic field in the biosensor cartridge

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

magnetic particles in the biosensor cartridge may be actuated by the magnetic field

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP2368116B1Biosensor system for actuating magnetic particles
Publication Date: 2019.07.03 SIEMENS HEALTHINEERS NEDERLAND BV
  • EP2368116B1 patent drawingFigure 1
  • EP2368116B1 patent drawingFigure 2
  • EP2368116B1 patent drawingFigure 3

AI summary

The application discloses a biosensor system (1) comprising: a biosensor cartridge (30), a first biosensor magnet assembly (10) for generating a magnetic field in the biosensor cartridge comprising two magnetic subunits (20a, 20b) each having a core (22a, 22b) with a top surface (24) separated by a gap (25), and wherein the sensor surface comprised by the biosensor cartridge is arranged above the top surfaces of the cores, wherein the two subunits are adapted to generate a magnetic field between the first subunit and the second subunit with magnetic field lines essentially in parallel to the sensor surface to exert forces at magnetic particles in the cartridge. By employing the system for controlling the movement of magnetic particles in immunoassays, more reliable test results are achieved.