Dendritic Signal Amplification in SPR Binding Detection

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Solution Overview

Problem

Current SPR assays face limitations in sensitivity and throughput due to unspecific binding, high reagent consumption, and complex detection configurations, particularly in flow cell formats, which hinder efficient amplification of binding events between analytes and binding agents.

Innovation Solution

The method involves combining multivalent molecules in a fluidic system for dendritic amplification by mixing two enhancement molecules simultaneously before the detection area, allowing for increased amplification efficiency and reduced constraints on detection devices, using a fluidics system with conduits that mix fluids at a junction and direct the mixed fluids over a solid support for surface plasmon resonance detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sequential injection of enhancement reagents is used, then binding events can be detected, but sensitivity is limited due to limited binding sites for enhancement molecules

Engineering Contradiction:
Improvedetection sensitivityVSAvoidnumber of binding sites
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent combines multiple enhancement reagents (polyclonal antibody and anti-rabbit IgG) into a single simultaneous injection mixture, allowing both reagents to bind to the analyte-antibody complex at the same time. This merging approach creates a dendritic amplification structure that significantly increases the number of available binding sites and enhances detection sensitivity compared to sequential injection methods.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If large complexes are used for enhancement, then signal amplification is achieved, but binding capacity to sensor chips with dextran matrix is lost

Engineering Contradiction:
Improvesignal amplificationVSAvoidbinding capacity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the physical parameters of the enhancement system by using simultaneously injected multivalent molecules that form dendritic structures in solution rather than pre-formed large complexes. This parameter change maintains binding capacity to the sensor chip surface while achieving signal amplification through the dendritic arrangement of enhancement molecules.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If alternately injecting two enhancement molecules is used, then dendritic amplification is achieved, but assay time increases and material consumption increases

Engineering Contradiction:
Improveamplification efficiencyVSAvoidassay time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the injection of multiple enhancement reagents into a single simultaneous injection event. The mixture of polyclonal antibody and anti-rabbit IgG is injected together, allowing both reagents to bind concurrently and form dendritic structures in a single step, thereby reducing assay time and reagent consumption while maintaining amplification efficiency.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If laminar flow-assisted dendritic amplification is used, then signal amplification is achieved, but high demands are placed on flow conditions and detection device choices are limited

Engineering Contradiction:
Improvesignal amplificationVSAvoidflow condition requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the dendritic amplification process from the complex laminar flow system and implements it in a simpler flow cell configuration. By simultaneously injecting enhancement reagents that form dendritic structures in the flow cell rather than relying on laminar flow merging, the method reduces demands on flow conditions and expands compatibility with different detection devices.

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 approach achieves significantly amplified detection signals, enabling the detection of trace amounts of analytes with improved sensitivity and reduced reagent consumption, as demonstrated by a 15-fold increase in signal compared to sequential injection methods.

Implementation Method 1

Laminar flow-assisted dendritic amplification is a signal amplification method for biomolecular binding events in microchannels

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Implementation Method 2

mixing a solution of a pair of multivalent molecules in a fluidic system and measuring the signal immediately after the two solutions have been substantially mixed

Methodology Applied
Scientific EffectMixing:

Implementation Method 3

surface plasmon resonance (SPR) by mixing a solution of a pair of multivalent molecules in a fluidic system and measuring the signal immediately after the two solutions have been substantially mixed

Methodology Applied
Scientific EffectSurface plasmon resonance:

Implementation Method 4

dendritic amplification is combined surface plasmon resonance (SPR) by mixing a solution of a pair of multivalent molecules

Methodology Applied
Scientific EffectDendritic amplification:

Implementation Method 5

a pair of multivalent molecules in a fluidic system

Methodology Applied
Scientific EffectMultivalent binding:

Data Source

PatentEP2798353B1Method for detection of binding
Publication Date: 2020.07.08 CYTIVA SWEDEN AB
  • EP2798353B1 patent drawingFigure 1
  • EP2798353B1 patent drawingFigure 2
  • EP2798353B1 patent drawingFigure 3

AI summary

The present invention relates to a method for detection of binding or interaction events between a binding agent and its corresponding analyte (such as an antibody and an antigen) in which a signal is detected which is substantially more amplified and thus easier to detect than in prior art systems. The method comprises simultaneous but separate addition of a first enhancement reagent having affinity for said analyte and a second enhancement reagent having affinity for the first enhancement reagent wherein the first enhancement reagent binds to the analyte and the second enhancement reagent binds to the first enhancement reagent, and, wherein the first and second enhancement reagents have more than one binding site so that they are able to bind to each other to thereby amplify a detectable signal from the binding event.