Lateral Flow Assay Gold Nanoparticle Size Optimization
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Solution Overview
Problem
Conventional lateral flow assays using large gold nanoparticles are not sensitive enough due to the color range limitations of larger particles, resulting in inadequate color change detection for analytes, and existing technologies are time-consuming and expensive.
Innovation Solution
A lateral flow assay device utilizing gold nanoparticles of 10-20 nm in size conjugated with peptides or antibodies that specifically bind to target analytes, allowing for capillary flow and colorimetric detection from red to purple within 60-300 seconds, enhancing sensitivity and specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large gold nanoparticles (40-100 nm) are used in lateral flow assays, then the assay can detect analytes using antibody conjugates, but the sensitivity is insufficient (65-70%) and color change detection is inadequate because larger particles already appear purple
Solution Approach 1:
The patent changes the critical parameter of gold nanoparticle size from the conventional 40-100 nm range to a smaller 10-20 nm range. This parameter change transforms the particle color from purple to red, enabling visible color change detection during aggregation while simultaneously improving detection sensitivity beyond the conventional 65-70% limit
2Measurement precision
If conventional ELISA techniques are used for protein analyte detection, then accurate detection can be achieved, but the process is time consuming and expensive
Solution Approach 1:
The patent replaces the complex mechanical and chemical systems of conventional ELISA (multiple washing steps, substrate additions, incubation periods) with a simplified lateral flow system using gold nanoparticle aggregation. This substitution maintains detection accuracy while dramatically reducing time and cost requirements
Solution Approach 2:
The patent utilizes the inherent color change properties of gold nanoparticles (from red to purple upon aggregation) as a direct visual readout mechanism, eliminating the need for expensive chromogenic substrates and complex detection equipment required by conventional ELISA, thereby reducing both time and cost
3Productivity
If label-free technologies such as SPR or piezoelectric devices are used, then rapid detection can be achieved, but costly and complex infrastructure is required
Solution Approach 1:
The patent employs disposable lateral flow strips with gold nanoparticle conjugates that can be discarded after single use, replacing expensive and complex reusable instruments like SPR or piezoelectric devices. This approach achieves rapid detection while eliminating the need for costly infrastructure
Solution Approach 2:
The lateral flow assay performs self-detection through visible color changes that occur automatically as gold nanoparticles aggregate upon binding to target analytes. This eliminates the need for complex external detection equipment, power supplies, or trained operators required by label-free technologies
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 device achieves 90%-92% sensitivity and 98%-100% specificity for detecting SARS CoV2 virus, with a rapid and cost-effective method for quantitatively detecting enveloped viruses like SARS CoV1, SARS CoV2, MERS CoV, influenza, Hepatitis B, and Ebola virus.
Implementation Method 1
Gold nanoparticles have a high extinction coefficient due to plasmonic properties of the particles. Aggregation of gold nanoparticles causes a big shift in the extinction spectrum of suspensions shown as a color change from red to purple
Implementation Method 2
The aggregation of gold nanoparticles happens in a controlled fashion and was used as a sensor
Implementation Method 3
The solid support permits capillary flow of the liquid sample comprising the target analyte from the sample pad to the absorbent pad
Data Source
AI summary
A lateral flow assay device for detection of an analyte in a sample and a method of detection thereof is provided. A quantitative assay for detection of an analyte in a sample is provided. A conjugate is provided. A method of diagnosing COVID 19 in a patient is provided.