Colloidal Palladium Nanoparticles for Lateral Flow Immunoassay Sensitivity

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Solution Overview

Problem

Lateral flow immunoassays face limitations in sensitivity, especially when relying on visual readouts with colloidal gold or latex, which are temperature and desiccation sensitive, and alternative non-enzymatic amplification systems like silver precipitation are complex and prone to signal loss.

Innovation Solution

Development of colloidal palladium nanoparticles that provide a direct replacement for colloidal gold or latex, offering a 30-fold increase in sensitivity with a five-minute reaction time and stability up to 80°C, allowing for rapid, catalytic preparation of a highly-colored dye at room temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If colloidal gold or latex particles are used as visual labels, then the assay can be read by unaided eye, but the sensitivity is limited and the particles are temperature and desiccation sensitive

Engineering Contradiction:

ImprovesensitivityVSAvoidtemperature and desiccation sensitivity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the material parameter from colloidal gold/latex to catalytic particles (colloidal palladium or magnetic particles). This material substitution enables catalytic amplification reactions that produce highly colored dyes, achieving 30-fold sensitivity improvement while the catalytic particles themselves remain stable under temperature and desiccation conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the detection function from the colloidal particles themselves and transfers it to a catalytic amplification system. The catalytic particles serve only as catalysts, and the actual detection signal comes from the amplified dye product, separating the stable catalytic component from the sensitive detection component.

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If non-enzymatic amplification systems like silver precipitation are used, then sensitivity can be increased, but the system becomes complex and prone to signal loss

Engineering Contradiction:

ImprovesensitivityVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses stable, non-enzymatic catalytic particles (colloidal palladium or magnetic particles) that can be dried and stored without degradation. These replace complex enzymatic systems, providing a simpler, more robust amplification system that maintains sensitivity without the complexity and signal loss problems of previous approaches.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces complex chemical precipitation systems (silver precipitation) with a simpler catalytic oxidation system using hydrogen peroxide and catalytic particles. This substitution simplifies the reagent system while maintaining amplification capability, reducing the number of steps and potential failure points.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If enzymes are used for amplification, then sensitivity can be enhanced, but the enzymes degrade during long-term storage due to temperature and desiccation sensitivity

Engineering Contradiction:

ImprovesensitivityVSAvoidstorage stability

Core Design Contradiction:

Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The patent employs non-enzymatic catalytic particles that are inherently stable under storage conditions. These particles do not degrade during long-term storage at various temperatures or when dried, providing a permanent, stable alternative to enzymes while maintaining the ability to catalyze amplification reactions when needed.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the catalytic mechanism from enzymatic to non-enzymatic catalysis. The catalytic particles (colloidal palladium or magnetic particles with catalytic coatings) provide a stable alternative to enzymes, maintaining catalytic activity without the temperature and desiccation sensitivity that limits enzyme storage stability.

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 colloidal palladium nanoparticles enhance sensitivity in lateral flow immunoassays, maintaining stability and enabling rapid, visually readable results suitable for field applications, with potential applications in malaria surveillance and drug detection.

Implementation Method 1

catalytic particles based on colloidal palladium that are a direct replacement for the colloidal gold or colored latex visual labels

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

catalytic preparation of a highly-colored dye at room temperature

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11340217B2Catalytic particles for increased sensitivity in lateral flow immunoassays

Publication Date: 2022.05.24 THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY

AI summary

The present invention provides a method for preparing colloidal palladium nanoparticles and using them for increased sensitivity in lateral flow immunoassays. Glutaraldehyde is used in preparing the colloidal palladium that allows rapid attachment of biomolecules. Colloidal palladium nanoparticles are labeled with a protein, such as a biomolecule or an antibody. These labeled colloidal palladium particles catalytically develop a dye to detect the presence of an analyte.