Lateral Flow Assay Dual-Phase Binding for Analyte Detection
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Solution Overview
Problem
Existing lateral flow assay devices rely solely on the capture of analytes at the test zone as the liquid sample migrates, which may not efficiently capture analytes that form slower-binding complexes.
Innovation Solution
The assay method involves contacting the liquid biological sample with a ligand-target conjugate in a liquid phase, forming a ligand-target-analyte complex, and then contacting this complex with a receptor-label conjugate to form a detectable complex, which is subsequently captured on a surface with a capture agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analyte capture is performed only at the test zone as liquid sample migrates, then device simplicity is maintained, but detection sensitivity is insufficient for slower-binding complexes
Solution Approach 1:
The assay is divided into two distinct phases: a liquid phase binding step where analyte targets are incubated with the sample to form complexes, and a subsequent solid phase capture step at the test zone. This segmentation allows each phase to be optimized independently - the liquid phase provides sufficient time for slower-binding complexes to form, while the solid phase enables efficient capture and detection at the test zone.
Solution Approach 2:
The binding between analyte targets and sample components is performed in advance in the liquid phase before the sample reaches the test zone. This preliminary action ensures that complexes have sufficient time to form and stabilize, improving detection sensitivity for slower-binding interactions without requiring extended incubation time at the test zone itself.
2Measurement precision
If binding time is extended to allow slower-forming complexes to develop, then detection sensitivity improves, but assay time increases
Solution Approach 1:
The assay timeline is segmented into a liquid phase binding period and a solid phase capture period. The liquid phase provides extended binding time for slower-forming complexes without extending the time required at the test zone, as binding and capture occur in sequence rather than simultaneously.
Solution Approach 2:
The liquid flow system is designed to maintain sample flow through the device while allowing sufficient residence time in the liquid phase for binding to occur. The hydraulic design ensures that the sample remains in contact with analyte targets long enough for slower-binding complexes to form, yet continues moving to prevent excessive overall assay time.
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
This approach enhances analyte detection by allowing binding to occur in both solution and solid phases, improving sensitivity, especially for slower-forming complexes, and providing a stable and active presentation of targets for capture.
Implementation Method 1
the ligand-target conjugate binds to at least a fraction of the analyte to form a ligand-target-analyte complex
Implementation Method 2
contacts analyte in the biological sample and the complex from step a) with a receptor-label conjugate, to form an analyte-receptor-label complex, and a ligand-target-analyte-receptor-label complex
Implementation Method 3
captures the labeled complexes from step b) on a surface comprising a capture agent capable of binding ligand
Data Source
AI summary
Disclosed herein are assay methods, lateral flow assay test strips, and devices for improved analyte detection. Analyte binding to target is performed both in solution phase and with a target immobilized on a surface, resulting in improved analyte detection.