Multiply Labeled Polymeric Constructs for Low-Signal Flow Assays
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Solution Overview
Problem
Existing lateral flow assays are limited in sensitivity due to the inability to amplify the detectable signal beyond one moiety per sample molecule, leading to false negatives when biomolecule concentrations are low.
Innovation Solution
The use of phage capsids with multiple viral coat proteins, each equipped with affinity peptides and binding partners, allows for significant signal amplification by attaching multiple detectable markers to a single target molecule through a branching structure, eliminating the need for chemical treatments that inhibit antibody function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lateral flow assays use one detectable moiety per sample molecule, then the assay structure remains simple, but detection sensitivity is limited and false negatives occur at low biomolecule concentrations
Solution Approach 1:
The assay system is segmented into distinct functional components: sample molecules, affinity binding sites (capture antibodies), and detectable moieties (fluorescent beads). This segmentation allows each component to be optimized independently while maintaining overall system simplicity.
Solution Approach 2:
Multiple detectable moieties are nested within a single binding complex formed by the affinity binding site. Each sample molecule bound by a capture antibody can associate with multiple fluorescent beads, creating a nested structure that amplifies the detectable signal without complicating the overall assay architecture.
2Measurement precision
If nucleic acid amplification techniques are used to increase molecule concentration, then detection sensitivity improves, but additional hardware and reagents are required
Solution Approach 1:
The assay system performs signal amplification through self-association of detectable moieties with the affinity binding sites, eliminating the need for external amplification hardware or complex reagent systems. The binding chemistry itself generates the amplification effect.
Solution Approach 2:
The system changes the parameter of detectable signal intensity by increasing the number of detectable moieties per binding event, rather than changing the concentration of target molecules through amplification. This parameter change achieves sensitivity improvement without requiring amplification hardware.
3Measurement precision
If fluorescence detection with labelling is used, then detection sensitivity improves, but cost increases
Solution Approach 1:
The system uses multiple copies of detectable moieties (fluorescent beads) associated with each binding event to amplify the signal. This copying approach increases sensitivity while using inexpensive, readily available fluorescent bead materials.
Solution Approach 2:
The system optimizes the parameter of detectable signal by increasing bead count per binding event rather than using expensive labelling chemistries on each target molecule. This parameter change maintains sensitivity while reducing manufacturing cost.
4Reliability
If lateral flow assays require sufficient amounts of detected molecules, then the assay remains simple, but it produces false negatives when biomolecule concentrations are low
Solution Approach 1:
Multiple detectable moieties are nested within each binding complex, allowing the system to detect low concentrations of biomolecules by accumulating sufficient signal from multiple beads per bound target molecule, thereby reducing the detection threshold.
Solution Approach 2:
The system changes the detection threshold parameter by increasing signal amplification through multiple detectable moieties per binding event, enabling reliable detection at lower biomolecule concentrations without sacrificing assay simplicity.
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 detection sensitivity by 25-70 times, enabling the detection of small numbers of target molecules in a short time without the need for additional hardware or reagents, and is applicable to both nucleic acid and non-nucleic acid biomolecules.
Implementation Method 1
a polymeric molecular construct comprising a region that is specific for a target, the polymeric molecule having multiple affinity binding sites wherein at least two of the affinity binding sites are configured to bind to a detectable nanoparticle
Data Source
AI summary
The present invention relates to methods, kits and devices for detecting a quantity of target molecule. The invention is particularly relevant to techniques carried out on a flow based assay device. Each biological target molecule is a protein capsid decorated with multiple copies of affinity tags and/or multiple copies of protein or peptide binding partners in order to bind a plurality of detectable markers.