Offset Gate Biosensor Dipole Detection
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Solution Overview
Problem
Existing biosensors, particularly ISFETs, require high concentrations of immobilized targets and lengthy sample preparation, making real-time monitoring and measurement resolution impractical for detecting biological pathogens in fluids.
Innovation Solution
A biosensor apparatus utilizing an offset field effect transistor gate with molecular probes that leverage a target's strong dipole moment as an electric field shunt between the gate and channel region, allowing for real-time detection of a single target without the need for filtration, reagents, or target amplification, and compatible with integrated circuit manufacturing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ISFET sensors utilize large gate areas with multiple immobilized targets, then detection sensitivity is improved, but device complexity and sample preparation time increase
Solution Approach 1:
The gate area is divided into multiple discrete target regions, each containing a specific immobilized target. This segmentation allows the sensor to detect multiple different pathogens simultaneously while maintaining a manageable device structure, resolving the contradiction between detection sensitivity and device complexity.
Solution Approach 2:
Different regions of the gate area are functionalized with different molecular probes specific to different targets. This local quality approach enables each region to independently detect its specific target, improving overall detection sensitivity without requiring a uniformly complex device structure.
2Measurement precision
If ISFET sensors require culturing of biological samples, then measurement accuracy is improved, but detection time increases
Solution Approach 1:
Molecular probes are pre-immobilized on the gate area before sample introduction. These probes are ready to immediately bind to their specific targets upon sample introduction, eliminating the need for time-consuming culturing steps while maintaining accurate detection capability.
Solution Approach 2:
The mechanical/biological culturing process is replaced with direct electrical detection using the field effect transistor. The sensor directly detects the electrical properties of targets bound to molecular probes, substituting the time-consuming biological amplification and culturing steps with immediate electrical measurement.
3Reliability
If ISFET sensors require filtration and reagent addition, then detection reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The sensor system performs self-detection without requiring external filtration or reagent addition. The molecular probes on the gate area automatically bind to their specific targets in the sample, and the field effect transistor automatically detects the binding event, eliminating manual sample preparation steps while maintaining reliable detection.
Solution Approach 2:
Molecular probes serve as intermediaries between the sample and the detector. These probes specifically bind to targets of interest, enabling reliable detection without the need for complex sample preparation, filtration, or reagent addition steps that would otherwise be required.
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
Enables the detection and monitoring of a single microbe in real-time with reduced sample preparation, achieving high measurement sensitivity and compatibility with existing manufacturing techniques.
Implementation Method 1
utilize the target's strong dipole moment (high relative permittivity) as an electric field shunt between the offset gate and the channel region
Implementation Method 2
utilize the target's strong dipole moment (high relative permittivity) as an electric field shunt between the offset gate and the channel region
Data Source
Figure 1A~5
Figure 6~7
Figure 8A~8E
AI summary
A biosensor has one or more field effect transistors each comprising a source region and a drain region separated by a channel region and a gate positioned offset and spaced from the channel region. The biosensor also has one or more molecular probes coupled to at least one of the channel region and the offset gate, the one or more molecular probes configured to mate with at least one target. A method for detection of a target is also disclosed. One or more targets are immobilized as an electric field shunt between an offset gate and a channel region for one or more biosensors. A target measurement value is determined in proportion to a number of the one or more biosensors having the electric field shunt.