Lateral Flow Immunoassay Device with Segmented Flow Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current rapid lateral flow diagnostic tests for HIV lack built-in controls to verify sample adequacy and reagent integrity, leading to false negative results due to inadequate samples or deteriorated reagents, and have limited reading windows and susceptibility to backflow, which restricts their usability and accuracy.
Innovation Solution
The development of a rapid lateral flow immunoassay device with separate flow paths to evaluate sample adequacy and confirm reagent immunoreactivity, using identical antigens and particulate markers in both paths to ensure accurate results, and a design that prevents backflow by using a large absorbent pad and evaporation vents, allowing for extended reading windows and improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid lateral flow diagnostic tests are used without built-in controls, then the test is simple and quick, but false negative results occur due to inadequate samples or deteriorated reagents
Solution Approach 1:
The test device is divided into separate flow paths: a test pathway for detecting specific antibodies and a control pathway for evaluating sample adequacy and reagent integrity. This segmentation allows independent optimization of each function while maintaining overall test simplicity and speed.
Solution Approach 2:
A control monoclonal antibody serves as an intermediary reagent in the control pathway, binding to the control antigen to produce a visible line. This intermediary mechanism provides a reliable indicator of sample adequacy and reagent functionality without interfering with the primary test results.
2Device complexity
If conventional lateral flow tests are used, then the device design is simple, but backflow of reagents occurs and reading window is limited
Solution Approach 1:
Evaporation vents are pre-positioned in the test device structure to facilitate controlled evaporation of excess liquid from the absorbent pad during the test process. This preliminary action prevents backflow of reagents and extends the reading window without adding complex mechanical components.
Solution Approach 2:
The test device utilizes phase transition (evaporation) of the liquid sample and reagents through controlled evaporation vents to manage fluid dynamics. This natural phase transition mechanism prevents backflow and extends the readable time window while maintaining simple device design.
3Reliability
If identical antigens and particulate markers are used in both flow paths, then test reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The same control antigen and control monoclonal antibody are used in both the test pathway and control pathway, creating a universal reagent system. This multi-functionality approach improves test reliability by ensuring consistent reagent performance across both pathways while simplifying manufacturing through reduced reagent variety.
4Reliability
If controls for sample adequacy and reagent reactivity are added, then false negatives are reduced, but device complexity increases
Solution Approach 1:
The control pathway is merged with the test pathway in terms of fluid flow, where the control reagents are positioned downstream in the same flow channel. This merging approach provides reliable control functionality while minimizing structural complexity and maintaining compact device design.
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 solution enhances the accuracy of rapid lateral flow immunoassays by reducing false negatives, extending the reading window from minutes to hours, and maintaining test sensitivity, thereby improving user confidence and test reliability.
Implementation Method 1
a large absorbent pad... that allows for extended reading windows
Implementation Method 2
evaporation vents, allowing for extended reading windows
Implementation Method 3
capillary lateral flow for rapid detection of ligands within biologic fluids
Data Source
AI summary
Methods and devices for rapid lateral flow immunoassays to detect specific antibodies within a liquid sample while also validating the adequacy of the liquid sample for the presence of immunoglobulin and the integrity and immunoreactivity of the test reagents that detect the antibodies of interest, without requiring instrumentation. The methods and devices provide for delivery of a diluted liquid sample to a single location that simultaneously directs the liquid flow along two or more separate flow paths, one that serves as a positive control to confirm that all critical reagents of the test are immunoreactive, and that the sample being tested is adequate, and the other to detect specific antibodies if present.