Chromatography Carrier PEG Blocking for Sensitivity and False Positives

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Solution Overview

Problem

Current immunochromatography methods face challenges in achieving high sensitivity while minimizing false positives, particularly when using amplification techniques, due to nonspecific adsorption issues.

Innovation Solution

The method involves immobilizing polyethylene glycol with a molecular weight between 7000 and 9000 on an insoluble carrier, along with a washing liquid and amplification liquid containing a reducing agent, to suppress nonspecific adsorption and enhance signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If amplification techniques are used to enhance detection sensitivity, then detection sensitivity is improved, but false positives increase due to nonspecific adsorption

Engineering Contradiction:
Improvedetection sensitivityVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

Polyethylene glycol (PEG) with molecular weight 7000-9000 is used as an intermediary substance that specifically suppresses nonspecific adsorption of amplification reagents to the insoluble carrier. The PEG acts as a blocking agent that prevents false positive signals while allowing specific antigen-antibody reactions to proceed, thereby resolving the contradiction between detection sensitivity and false positive rate

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention specifies a particular molecular weight range (7000-9000) for polyethylene glycol to optimize its blocking effectiveness. This parameter optimization ensures that the PEG is large enough to effectively block nonspecific adsorption sites on the insoluble carrier, yet small enough to allow diffusion of amplification reagents and maintain high detection sensitivity while minimizing false positives

Inventive Principle:
Principle #35Parameter changes

2Reliability

If blocking agents are used to suppress nonspecific adsorption, then false positives are reduced, but detection sensitivity may be compromised

Engineering Contradiction:
Improvefalse positive rateVSAvoiddetection sensitivity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The invention optimizes the molecular weight parameter of polyethylene glycol to the specific range of 7000-9000, which has been determined to provide the best balance between blocking effectiveness and signal preservation. This parameter optimization ensures that the PEG effectively suppresses nonspecific adsorption while maintaining high detection sensitivity for trace substances

Inventive Principle:
Principle #35Parameter changes

3Reliability

If polyethylene glycol with inappropriate molecular weight is used, then nonspecific adsorption suppression is insufficient, but using correct molecular weight PEG achieves high signal-to-noise ratio

Engineering Contradiction:
Improvenonsspecific adsorption suppressionVSAvoidsignal-to-noise ratio
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The invention precisely defines the molecular weight range of polyethylene glycol as 7000-9000 to optimize its performance. PEG within this range provides sufficient steric hindrance to block nonsspecific adsorption sites effectively, while maintaining appropriate solubility and mobility to allow specific antigen-antibody complex formation and amplification, thereby achieving high signal-to-noise ratio

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The reactive site on the insoluble carrier is designed as a composite structure comprising both polyethylene glycol (blocking component) and antibody (specific recognition component). This composite design allows the PEG to suppress nonspecific adsorption while the antibody maintains specific binding capability, achieving both high reliability and measurement precision simultaneously

Inventive Principle:
Principle #40Composite materials

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 approach effectively reduces false positives and achieves a high signal-to-noise ratio, enabling the detection of trace substances with increased sensitivity.

Implementation Method 1

the reactive site includes (i) a second bondable substance which can be bonded to the specimen or a substance having affinity to the first bondable substance which can be bonded to the specimen, and (ii) polyethylene glycol having the molecular weight from 7000 to 9000

Methodology Applied
Scientific EffectNonspecific adsorption suppression: Adsorption

Implementation Method 2

an amplification liquid, in which the reactive site on the insoluble carrier includes (i) a second bondable substance which can be bonded to the specimen or a substance having affinity to the first bondable substance which can be bonded to the specimen, and (ii) polyethylene glycol having the molecular weight from 7000 to 9000

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP2770324B1Chromatography method, chromatography kit, and method of producing an insoluble carrier for chromatography
Publication Date: 2019.05.15 FUJIFILM CORP
  • EP2770324B1 patent drawingFigure 1~3

AI summary

A chromatography method including a step of developing a complex of a specimen and a labeled substance modified by a first bondable substance which can be bonded to the specimen on an insoluble carrier, a step of capturing the complex of the specimen and the labeled substance at a reactive site on the insoluble carrier, a step of washing the reactive site on the insoluble carrier using a washing liquid, a step of detecting the specimen which is captured at the reactive site after a signal of the labeled substance is amplified by an amplification liquid, in which the reactive site on the insoluble carrier includes (i) a second bondable substance which can be bonded to the specimen or a substance having affinity to the first bondable substance which can be bonded to the specimen, and (ii) polyethylene glycol having the molecular weight from 1,500 to 10,000.