SPFS Lectin Sugar Chain Detection

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Solution Overview

Problem

Current methods for analyzing sugar chains, particularly in blood, face challenges with sensitivity and quantitativity due to high dissociation rates of lectin interactions, leading to difficulties in detecting small amounts of sugar chains and non-specific reactions.

Innovation Solution

The use of a fluorescently labeled lectin with a high dissociation rate constant as a secondary antibody in a surface plasmon excitation enhanced fluorescence spectroscopy (SPFS) method within a channel system, which suppresses non-specific adsorption and allows for real-time, quantitative measurement of small sugar chain amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If evanescent wave excitation is used for fluorescence detection, then selective observation of captured fluorescent substances is enabled, but detection sensitivity is insufficient for small amounts of sugar chains

Engineering Contradiction:
Improveselective observation capabilityVSAvoiddetection sensitivity
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent changes the excitation method from conventional evanescent wave excitation to surface plasmon excitation. This parameter change in the excitation mechanism enhances the electromagnetic field intensity at the metal-dielectric interface, enabling detection of much smaller amounts of sugar chains (10^-12 to 10^-15 mol) while maintaining selective observation capability through the confined evanescent field.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If lectin is used as a probe for sugar chain detection, then specific binding to sugar chains is achieved, but non-specific adsorption occurs reducing measurement accuracy

Engineering Contradiction:
Improvespecific binding capabilityVSAvoidnon-specific adsorption
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a solid phase carrier as an intermediary between the lectin probe and the sugar chain analyte. The lectin is immobilized on the solid phase carrier surface, which provides a stable platform for specific binding while reducing non-specific adsorption to surrounding areas. The solid phase carrier acts as a mediator that concentrates the interaction at a defined location, improving signal-to-noise ratio.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If microarray format is used for lectin immobilization, then multiple lectins can be analyzed simultaneously, but quantitativity is insufficient

Engineering Contradiction:
Improvemulti-lectin analysis capabilityVSAvoidquantitativity
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent creates a universal solid phase carrier system that can accommodate multiple different lectins while maintaining quantitative measurement capability. The standardized solid phase carrier with controlled surface properties allows each lectin to be analyzed with consistent binding conditions, enabling both multi-lectin analysis and accurate quantification through the enhanced surface plasmon excitation fluorescence detection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables highly sensitive and rapid detection of small sugar chain amounts in blood, reducing non-specific reactions and improving quantitativity, allowing for accurate measurement of tumor markers and other analytes.

Implementation Method 1

surface plasmon excitation enhanced fluorescence spectroscopy (SPFS)

Methodology Applied
Scientific EffectSurface plasmon excitation enhanced fluorescence spectroscopy: Surface Acoustic Wave

Implementation Method 2

fluorescently labeled lectin

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

the binding between a sugar chain and a protein showing interaction with the sugar chain (representatively a lectin)

Methodology Applied
Scientific EffectLectin-sugar chain interaction: Adsorption

Data Source

PatentEP2738556B1Method for measuring amount of analyte and device for spfs
Publication Date: 2019.11.06 KONICA MINOLTA INC
  • EP2738556B1 patent drawingFigure 1
  • EP2738556B1 patent drawingFigure 2
  • EP2738556B1 patent drawingFigure 3

AI summary

[Problem] An object of the present invention is to provide a method by which the amount of a very small amount of analyte (in particular, one having a sugar chain) can be measured with a high accuracy and a device which is used for said measurement method. [Means for Solution] The method for measuring the amount of an analyte according to the present invention is characterized in that a lectin labeled with a fluorescent dye, preferably said lectin whose dissociation rate constant [kd] is from 1.0 x 10-6 to 1.0 x 10-3 (S-1), is used as a secondary antibody in a sandwich assay using a surface plasmon excitation enhanced fluorescence spectroscopy [SPFS; Surface Plasmon-field enhanced Fluorescence Spectroscopy].