Biosensor Capture Molecules with Differential Dissociation Rates
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Solution Overview
Problem
Conventional tethered particle biosensing techniques face challenges in discriminating between bound and unbound states of tethered particles due to sub-optimal dissociation rates of capture molecules, affecting the sensitivity and specificity of target substance detection.
Innovation Solution
Employing two capture molecules with dissociation rates that differ by a factor of three or more, allowing for enhanced switching rates and improved biosensing capabilities, including increased detectability, signal-to-noise ratio, and calibration, while maintaining adequate distinguishability between binding states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If two capture molecules with equal dissociation rates are used, then the bound state lifetime is extended, but the switching rates are reduced and sensitivity is compromised
Solution Approach 1:
The patent applies parameter changes by using two capture molecules with different dissociation rates (koff1 and koff2) instead of equal rates. This differential parameter approach allows the system to optimize both bound state lifetime and switching rates simultaneously, resolving the contradiction between extending bound state duration and maintaining high switching activity for sensitive detection
2Reliability
If capture molecules with low dissociation rates are used, then the bound state lifetime is extended for better discrimination, but the association rate is reduced affecting sensitivity
Solution Approach 1:
The patent segments the capture molecule function into two distinct molecules with different kinetic properties. One capture molecule provides stable binding for reliable state discrimination, while the other enables faster switching and sensitivity. This functional segmentation resolves the contradiction between reliability and measurement precision
3Device complexity
If conventional capture molecules are used, then the system is simple, but the biosensing performance and signal-to-noise ratio are sub-optimal
Solution Approach 1:
The patent uses a composite approach by combining two different capture molecules with distinct dissociation rates on the same particle surface. This composite configuration creates enhanced biosensing performance with improved signal-to-noise ratio while maintaining practical system simplicity, resolving the contradiction between complexity and performance
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 enables effective detection of target substances at low concentrations with improved sensitivity and specificity, optimizing the biosensing system's performance by shortening the lifetime of the bound state for enhanced statistical analysis and signal generation.
Implementation Method 1
the particle and substrate are functionalized with capture molecules, both of which can bind to the target substance
Implementation Method 2
The motion of the tethered particle is typically measured optically using a light source to illuminate a liquid cell containing a multitude of particles
Implementation Method 3
Various microscopy imaging techniques may be used such as bright field illumination, dark field illumination, evanescent wave illumination
Data Source
AI summary
Provided herein is a method for biosensing a target substance [110] using a collection of particles [104] tethered to a surface [100] by tether molecules [102] and a plurality of capture molecules. A concentration of the target substance is determined from the time sequence of individual association/dissociation rates of the capture molecules. Competitive assay configurations are also described.