Diagnostic Device Using Gold Colloid Particles for Analyte Detection
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Solution Overview
Problem
Current diagnostic assays for analytes in bodily fluids face challenges in accurately detecting low levels of analytes, particularly in pregnancy testing, due to limitations in sensitivity and the risk of false positives, especially with agglutination and rapid detection methods.
Innovation Solution
A diagnostic device utilizing a biphasic substrate with a release medium and a capture medium, where the release medium includes a labeled conjugate with gold colloid particles of 60-80 nm and a capturable conjugate, reacting with analytes to form a complex that is captured by polymerized streptavidin on the capture medium, enhancing sensitivity and accuracy for low analyte detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If agglutination and rapid detection methods are used, then detection speed is improved, but false positives increase and sensitivity decreases
Solution Approach 1:
The patent introduces colloidal gold particles as an intermediary labeling agent that bridges the binding member and the analyte. These particles enable rapid visual detection through color change while maintaining high sensitivity and specificity, thus resolving the contradiction between fast detection and reliability by providing a stable, well-defined detection mechanism that reduces false positives
Solution Approach 2:
The patent optimizes the particle size of colloidal gold to 15-30 nm to achieve optimal balance between detection sensitivity and visual observability. This parameter optimization allows rapid detection with sufficient sensitivity, resolving the contradiction by tuning the physical parameters of the detection system to achieve both speed and reliability
2Measurement precision
If colloidal gold particles with mean particle size of 15-30 nm are used, then sensitivity is improved, but color intensity decreases
Solution Approach 1:
The patent carefully selects and optimizes the particle size parameter of colloidal gold to the specific range of 15-30 nm. This parameter optimization achieves the best compromise between detection sensitivity (improved by smaller particles) and color intensity (improved by larger particles), resolving the contradiction by finding the optimal parameter value that satisfies both requirements
Solution Approach 2:
The patent creates a composite structure by conjugating binding members with colloidal gold particles. This composite material combines the high sensitivity of small gold particles with the signal amplification capability of the binding member-analyte complex, thereby achieving both good sensitivity and adequate color intensity simultaneously
3Measurement precision
If smaller colloidal gold particles are used, then sensitivity is improved, but particle stability and retention decrease
Solution Approach 1:
The patent applies preliminary stabilization measures by carefully controlling the synthesis and conjugation process of colloidal gold particles with binding members. This preliminary action ensures that the small particles (15-30 nm) are properly stabilized before use, preventing aggregation and loss during the detection process, thus resolving the contradiction between sensitivity and stability
Solution Approach 2:
The binding member acts as an intermediary that connects the small colloidal gold particles to the analyte. This intermediary role not only provides sensitivity through the small particle size but also enhances stability by creating a stable complex structure that prevents particle loss during detection
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 provides improved sensitivity and accuracy in detecting low analyte levels, such as hCG, allowing for early detection of pregnancy and reducing false positives, with increased color intensity and better retention of streptavidin, leading to more reliable consumer-readable results.
Implementation Method 1
a label comprising a gold colloid... with increased color intensity
Implementation Method 2
a label comprising a gold colloid... with increased color intensity
Implementation Method 3
a biphasic substrate with a release medium and a capture medium... in fluid contact with the first portion
Data Source
Figure 1A~1E
Figure 2A~2B
Figure 2C~2E
AI summary
The invention comprises a device for detecting an analyte in a liquid sample deposited on a first portion of the device for transport to a second portion of the device that is in fluid contact with the first portion. In specific embodiments, the device comprises a labeled conjugate comprising a binding member reactive with a first epitope of the analyte and a label comprising a gold colloid, preferably having a mean particle size of 50 nm to 100 nm. In further embodiments, the device comprises a capture component comprising polymerized streptavidin. The diagnostic device is particularly useful in the preparation of pregnancy test kits.