Colorimetric Immunosenor for SARS-CoV-2 Detection
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Solution Overview
Problem
Current diagnostic methods for SARS-CoV-2 detection, such as RT-PCR and lateral flow assays, face challenges with complexity, timing requirements, need for specialized equipment, and low sensitivity, necessitating a rapid, simple, and highly specific detection method for SARS-CoV-2 in upper respiratory tract samples.
Innovation Solution
A colorimetric immunosensor using gold nanoparticles that immobilize antibodies specific to SARS-CoV-2 surface antigens, leveraging Localized Surface Plasmon Resonance (LSPR) to detect viral particles through clustering, allowing for rapid and sensitive identification without sophisticated instrumentation, utilizing a colloidal suspension of gold capture nanoparticles with antibodies in a buffer solution from upper respiratory tract samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RT-PCR is used for SARS-CoV-2 detection, then detection sensitivity is improved, but device complexity and timing requirements increase
Solution Approach 1:
The patent replaces complex mechanical and chemical systems (RT-PCR machinery, thermal cyclers) with a simplified optical detection system based on LSPR. Gold nanoparticles serve as the sensing element, eliminating the need for sophisticated instrumentation while maintaining high detection sensitivity through direct optical measurement of nanoparticle aggregation.
Solution Approach 2:
The patent extracts the essential detection function from complex RT-PCR systems by isolating the antigen-antibody recognition step and coupling it directly with LSPR detection. This removes unnecessary complexity while preserving the core detection capability, enabling rapid results without full PCR processing.
2Ease of operation
If lateral flow assays are used for SARS-CoV-2 detection, then ease of operation is improved, but detection sensitivity deteriorates
Solution Approach 1:
The patent changes the detection parameter from the low-sensitivity visual line readout of lateral flow assays to the highly sensitive LSPR optical signal. By monitoring changes in optical properties (absorbance, scattering) of gold nanoparticles, the system achieves both ease of operation and high detection sensitivity, overcoming the fundamental limitation of lateral flow technology.
3Measurement precision
If gold nanoparticles are used for SARS-CoV-2 detection, then detection sensitivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs standard Turkevich synthesis conditions to produce gold nanoparticles with consistent properties. By optimizing and controlling key parameters such as citrate-to-aurod ratio, reaction temperature, and pH, the method achieves reproducible nanoparticle production with sufficient precision for sensitive detection, without requiring ultra-precise manufacturing.
Solution Approach 2:
The nanoparticle synthesis method is self-regulating through the citrate reduction mechanism, where the citrate both reduces gold ions and stabilizes the formed nanoparticles. This self-organizing process naturally produces monodisperse nanoparticles with controlled size, reducing the need for external precision control mechanisms.
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
Enables rapid detection of SARS-CoV-2 within minutes with minimal sample volume, high specificity, and reduced costs, as the method relies on visual or quantitative changes in optical parameters, such as color shifts or transmittance measurements, suitable for identifying active infections.
Implementation Method 1
colorimetric biosensors based on gold nanoparticles, which use a physical property of gold nanoparticles, designated as Localized Surface Plasmon Resonance (LSPR), to monitor the colour change when different-size clusters are formed following the interaction between the analyte to be detected and the gold nanoparticles
Implementation Method 2
Biosensors based on specificity of interaction between an antigen and the corresponding antibody for determining the analyte of interest are commonly referred to as immunosensors
Data Source
AI summary
An in vitro method and a kit for detecting the SARS-CoV-2 virion using a colorimetric immunosensor in a biological sample from the upper respiratory tract of a subject is provided. The biological sample is a nasopharyngeal swab sample. The in vitro method and kit are based on the use of gold capture nanoparticles carrying on their surface at least one antibody capable of binding a SARS-CoV-2 surface antigen.