Aptamer Gold Test Strip With Universal Poly-DNA Probe Architecture
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Solution Overview
Problem
Existing aptamer-based colloidal gold lateral flow test strips lack universality, require repeated optimization for specific targets, and have low detection sensitivity and high preparation costs due to the need for re-spraying compounds on nitrocellulose membranes for each target.
Innovation Solution
A universal test strip design using a polyA-DNA probe anchored to gold nanoparticles, with streptavidin on the T line and a complementary DNA chain on the C line, allowing detection of different small-molecule substances by changing only the poly-DNA complementary to the aptamer, simplifying preparation and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a specific nucleic acid chain-streptavidin compound is sprayed on the T line for each test target, then the detection specificity is improved, but the universality and ease of manufacture deteriorate
Solution Approach 1:
The patent uses a universal polyA-DNA probe that can bind to different aptamers through complementary base pairing. The T line is fixed with streptavidin that binds to biotin-labeled aptamers, while the polyA-DNA probe with varying complementary sequences allows detection of different small-molecule targets without changing the membrane preparation, achieving multi-functionality
Solution Approach 2:
The detection system is divided into fixed components (streptavidin on T line, polyA anchor on AuNPs) and variable components (complementary DNA sequence that matches specific aptamers). This segmentation allows the same base structure to serve multiple detection purposes by simply changing the complementary sequence segment
2Measurement precision
If a specific nucleic acid chain-streptavidin compound is sprayed on the T line for each test target, then the detection specificity is improved, but the device complexity and preparation time increase
Solution Approach 1:
The same streptavidin-coated T line and polyA-DNA probe system can detect multiple different targets by simply changing the complementary DNA sequence, eliminating the need to prepare different compounds for each target and simplifying the overall device design
Solution Approach 2:
The polyA-DNA probe is pre-conjugated to AuNPs with a universal polyA anchor sequence. The complementary DNA segment is designed to match the specific aptamer, allowing pre-preparation of the probe conjugate that can be used with different aptamers, reducing on-site preparation complexity
3Measurement precision
If an aptamer is conjugated directly to AuNPs for competitive binding, then the detection sensitivity is improved, but the product stability deteriorates
Solution Approach 1:
The patent introduces a complementary DNA chain as an intermediary between the aptamer-AuNP conjugate and the T line. The complementary DNA binds to the polyA-DNA probe through stable base pairing, mediating the interaction and improving overall system stability while maintaining detection sensitivity
Solution Approach 2:
The system uses a composite structure where AuNPs are conjugated with aptamer, which then interacts with a complementary DNA chain that binds to polyA-DNA on the AuNP surface. This multi-component composite approach enhances stability through multiple binding interfaces
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 test strip achieves high sensitivity and specificity with a limit of detection as low as 0.18 ng/mL for small-molecule substances, rapid detection within 20 minutes, and improved reproducibility, while maintaining stability and reducing preparation complexity.
Implementation Method 1
a nucleic acid chain-streptavidin compound is usually sprayed on the T line
Implementation Method 2
an aptamer complementary chain aiming at the target and an artificially designed nucleic acid chain can be sprayed on the nitrocellulose (NC) membrane
Implementation Method 3
an aptamer is a small segment of structured oligonucleotide sequence (RNA or DNA) obtained by an in vitro screening technology-systematic evolution of ligands by exponential enrichment (SELEX), can be combined with corresponding target molecules (proteins, viruses, bacteria, cells, heavy metal ions and the like) with high affinity and strong specificity
Implementation Method 4
aptamer-labeled colloidal gold lateral flow test strip
Data Source
AI summary
The present disclosure discloses a universal aptamer-based colloidal gold lateral flow test strip for detecting small-molecule substances and belongs to the fields of analytical chemistry, medicine, environment, food safety detection, nano-biosensing and the like. An AuNPs@poly-DNA probe is used for rapidly and sensitively capturing an aptamer, streptavidin sprayed in a test zone and streptavidin-biotin-DNAc sprayed in a control zone do not need to be changed, and another substance can be detected only by changing a nucleic acid chain part of the AuNPs@poly-DNA probe. A universal colloidal gold lateral flow test strip, which is rapid, sensitive and low in cost, has been developed. The test strip method for detecting small-molecule substances is simple, convenient and rapid, and can be used for detection at any time. Only a test solution is needed to be added into a sample port and the test strip is completely developed after 5 min, thus an experiment result can be observed and the detection efficiency can be greatly improved. Qualitative analysis can be conducted by naked eyes, and quantitative analysis can be conducted by a colloidal gold test strip quantitative analyzer.