Buffer System for Particle-Based Immunoassays

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Solution Overview

Problem

Current suspension array fluorescence immunoassay (SAFIA) techniques face challenges in accurately analyzing food and feed samples due to matrix effects, leading to poor accuracy and overestimation of analyte concentrations, especially in samples with high protein, starch, or fat content, and require washing steps that are cumbersome and increase costs and time.

Innovation Solution

A buffer system comprising an extract dilution buffer with high and low hydrophilic-lipophilic balance (HLB) detergents and a polyanionic polymeric species, a stopping buffer with a protein crosslinker and SDS, and a secondary antibody dilution buffer with a polyglycol ether, which stabilizes samples, prevents non-specific binding, and enhances luminescent signal intensity, allowing for a wash-free analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If washing steps are used to remove matrix interference, then measurement precision is improved, but device complexity and analysis time increase

Engineering Contradiction:
Improveaccuracy of analyte concentration measurementVSAvoidcomplexity of washing steps and equipment requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes matrix components (proteins, fats, starches) from the sample before analysis using pre-treatment steps including solvent extraction, protein precipitation, and filtration. This extraction of interfering substances enables accurate measurement without requiring complex washing steps during the actual immunoassay, thus improving measurement precision while reducing operational complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary sample preparation and matrix removal steps before the actual immunoassay measurement. By completing the extraction and purification of matrix components in advance, the system avoids the need for complex washing steps during analysis, thereby improving accuracy while simplifying the measurement process and reducing equipment requirements

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If washing steps are used to eliminate matrix interference, then measurement precision is improved, but loss of time and analysis cost increase

Engineering Contradiction:
Improveaccuracy of analyte concentration measurementVSAvoidanalysis time required for washing steps
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs extraction techniques using solvents and precipitants to remove matrix components before analysis. By extracting interfering substances in advance, the system eliminates the need for time-consuming washing steps during the immunoassay, thereby improving measurement precision while significantly reducing analysis time

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs matrix removal and sample purification as preliminary steps before the actual measurement. This advance preparation removes interfering substances early in the process, eliminating the need for subsequent washing steps and thereby reducing total analysis time while maintaining high measurement precision

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If buffer system components are added to stabilize samples and prevent non-specific binding, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveaccuracy of analyte concentration measurementVSAvoidcomplexity of buffer system composition
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces buffer components and stabilization agents as intermediary substances that mediate between the sample matrix and the immunoassay reagents. These intermediaries prevent non-specific binding and stabilize samples without requiring complex washing steps, thereby improving measurement precision while adding manageable complexity through controlled chemical additions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies buffer composition parameters (pH, ionic strength, additive concentrations) to optimize sample stability and prevent non-specific binding. By adjusting these chemical parameters, the system improves measurement precision through controlled chemical environment modification, accepting increased compositional complexity as a trade-off for enhanced assay performance

Inventive Principle:
Principle #35Parameter changes

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 buffer system stabilizes samples, reduces matrix interference, and increases assay sensitivity and accuracy, enabling the detection of harmful substances in food and feed products, while eliminating the need for washing steps and reducing analysis time and equipment requirements.

Implementation Method 1

a first detergent having a high hydrophilic-lipophilic balance (HLB), a second detergent having a low HLB

Methodology Applied
Scientific EffectSurfactant: Surfactant

Implementation Method 2

a stopping buffer for stabilizing a read-out signal of the SAFIA by preventing unbound antibodies form reacting with a corresponding epitope, wherein the stopping buffer comprises: the analyte, a protein crosslinker, MeOH and SDS

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

a secondary antibody dilution buffer with a polyglycol ether, which stabilizes samples, prevents non-specific binding, and enhances luminescent signal intensity

Methodology Applied
Scientific EffectLuminescence enhancement: Luminescence

Implementation Method 4

Luminescence and scattering properties of the particles are then detected with multiple detectors

Methodology Applied
Scientific EffectLuminescence detection: Luminescence

Implementation Method 5

As the luminescence measurement is correlated to light scattering, bound antibodies on the particles and free antibodies can be discriminated

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4220161A1A buffer system for particle-based multiplexed immunoassays
Publication Date: 2023.08.02 BUNDESREPUBLIK DEUT VERTRETEN DURCH DEN BUNDESMINIST FUR WIRTSCHAFT & ENERGIE
  • EP4220161A1 patent drawingFigure 1
  • EP4220161A1 patent drawingFigure 2A~2C
  • EP4220161A1 patent drawingFigure 3

AI summary

A buffer system for detecting an analyte using a suspension array fluorescence immunoassay (SAFIA) comprising: (a) an extract dilution buffer for diluting an extract of a food or a feed sample to be analysed in the SAFIA, the extract dilution buffer comprising: a first detergent having a high hydrophilic-lipophilic balance (HLB), a second detergent having a low HLB, and a polyanionic species, wherein the high HLB is selected from a range of HLB-values of 8 through 13, and the low HLB is selected from the range of HLB-values of 14 through 20; (b) stopping buffer for stabilizing a read-out signal of the SAFIA by preventing unbound antibodies form reacting with a corresponding epitope, the stopping buffer comprising: the analyte, a protein crosslinker, MeOH and SDS, wherein the protein crosslinker is selected from formaldehyde or a linear and/or branched alkane or aromatic dialdehyde selected from: glyoxal, succinic aldehyde, glutaraldehyde, adipaldehyde, benzene dicarbaldehyde, and genipin; and (c) a secondary antibody dilution buffer for diluting a secondary antibody comprising the extract dilution buffer and a polyglycol ether of a fatty acid, wherein the secondary antibody is directed towards a primary antibody and comprises a luminescence label, and wherein the first antibody is directed towards the analyte and/or a hapten fixed at a particle's surface.