Planar Hall Biosensor Magnetic Field Optimization for Bio-particle Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current magnetic measurement systems based on Planar Hall magnetoresistive biosensors face challenges in detecting low concentrations of specific bio-particles and quantifying their interactions, particularly at concentrations ranging from nano-moles to pico-moles, while accounting for Van der Waals repulsive forces.

Innovation Solution

A magnetic measurement system utilizing an aptamer-based hybrid AMR/PHR sensor with a closed-loop magnetic track, optimized DC magnetic field amplitude, and signal processing to enhance sensitivity, combined with AC magnetic field application for improved noise reduction and interaction analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional magnetic measurement systems are used, then detection can be performed, but sensitivity is insufficient for detecting low concentrations of bio-particles

Engineering Contradiction:
Improvedetection sensitivityVSAvoidbio-particle concentration
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent optimizes the DC magnetic field amplitude parameter to maximize the sensitivity of the Planar Hall magnetoresistive biosensor. By carefully selecting and adjusting the magnetic field strength, the system achieves enhanced detection capability for low concentrations of bio-particles, resolving the contradiction between maintaining operational conditions and improving measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If DC magnetic field amplitude is increased to improve sensitivity, then detection precision improves, but noise increases

Engineering Contradiction:
Improvedetection precisionVSAvoidnoise
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent employs periodic modulation of the magnetic field combined with lock-in detection techniques. By applying AC magnetic field components and using synchronous detection, the system can extract weak signals from noisy backgrounds, achieving high detection precision without being overwhelmed by noise that would result from simply increasing DC field amplitude.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If measurement sensitivity is increased to detect femto-molar concentrations, then detection limit improves, but system complexity increases

Engineering Contradiction:
Improvedetection limitVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent utilizes a hybrid AMR/PHR (Anisotropic Magnetoresistive/Planar Hall Magnetoresistive) sensor structure that combines different magnetoresistive effects in a single integrated device. This composite sensor approach achieves ultra-sensitive detection at femto-molar concentrations while avoiding the need for multiple separate complex measurement systems, thereby improving detection limit without proportionally increasing system complexity.

Inventive Principle:
Principle #40Composite materials

4Measurement precision

If aptamer-based magnetic hybrid sensor is used, then sensitivity to specific bio-particles improves, but manufacturing complexity increases

Engineering Contradiction:
Improvespecificity and sensitivityVSAvoidsensor fabrication
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs pre-synthesized aptamers that are designed and prepared in advance with specific binding characteristics for target bio-particles. These pre-engineered molecular recognition elements are then integrated into the magnetic sensor system, allowing high specificity and sensitivity to be achieved without requiring complex real-time fabrication processes, thus improving measurement precision while maintaining reasonable ease of manufacture.

Inventive Principle:
Principle #10Preliminary action

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 system achieves ultra-sensitive detection of bio-particles down to femto-molar concentrations and effectively quantifies interactions by optimizing magnetic field amplitudes and noise reduction, enhancing sensitivity and accuracy in bio-particle measurement.

Implementation Method 1

an aptamer-based magnetic hybrid AMR/PHR sensor

Methodology Applied
Scientific EffectPlanar Hall effect: Hall Effect

Implementation Method 2

an aptamer-based magnetic hybrid AMR/PHR sensor

Methodology Applied
Scientific EffectAnisotropic magnetoresistance: Magnetoresistance

Implementation Method 3

a magnetic element for applying an actual DC constant magnetic field on the magnetic track

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP3252461B1A magnetic measurement system based on an ultrasensitive planar hall magnetoresistive biosensor (PHR) and a method for measuring low specific bioparticles concentrations and quantifying bio-particles interactions
Publication Date: 2021.05.26 UNIVERSITY OF MONTPELLIER
  • EP3252461B1 patent drawingFigure 1
  • EP3252461B1 patent drawingFigure 2
  • EP3252461B1 patent drawingFigure 3

AI summary

A magnetic measurement system (2) for measuring a concentration of specific bio-particles through a sensitive detection of magnetic particle labels comprises an aptamer-based magnetic hybrid AMR/PHR sensor (12) having an active surface (22) on which at least one magnetic particle (28) is ready to be or is closely bound through a sandwich-type aptamer structure that includes a captured unitary bio-particle. The magnetic measurement system is characterized in that an actual amplitude of an applied DC constant magnetic field onto the magnetic track (24) of the sensor (12) is closely located in a vicinity of an optimum amplitude of the permanent DC magnetic field comprised in a set of two optimum values H1, H2 of the permanent DC magnetic field, each optimum value H1, H2 maximizing locally the absolute value of a first quantity H⋅∂VMR∂H, where H is the amplitude of the applied magnetic field and ∂VMR∂H is the derivate of the differential voltage with respect to the magnetic field at the applied field H.