Graphene Transistor Sensor Layout for Liquid-Gated Biomarker Detection
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Solution Overview
Problem
Current diagnostic techniques for diseases such as viral or bacterial infections and cancer are often slow, require complex equipment, and are not suitable for fast, point-of-care testing, especially in decentralized settings, due to their reliance on optical signals and centralized lab processing.
Innovation Solution
A graphene field-effect transistor (GFET) sensor system with a specific configuration of source, drain, and gate electrodes, allowing for liquid gating and multiplexing, which enhances sensitivity and reproducibility, enabling accurate and reliable electrical readouts for biological and chemical sample analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical-based diagnostic techniques (ELISA, fluorescence tests) are used, then sensitivity and selectivity are improved, but device complexity and need for dedicated equipment increase
Solution Approach 1:
The patent replaces optical detection systems with electrical field-effect transistor-based detection. Instead of using optical signals that require complex transduction equipment, the invention uses electrical properties of graphene transistors to directly detect biomarker binding events, eliminating the need for dedicated optical transduction equipment while maintaining high sensitivity
Solution Approach 2:
The patent changes the detection parameter from optical signals to electrical conductance changes. By measuring changes in electrical properties of the graphene transistor channel when biomarkers bind to probes, the system achieves simplified readout electronics while preserving detection sensitivity
2Measurement precision
If PCR technique is used, then sensitivity and reliability are improved, but speed deteriorates (hours to get result)
Solution Approach 1:
The patent uses pre-functionalized graphene transistors with biomarker-specific probes attached before sample introduction. This preliminary preparation of the sensing surface enables direct detection upon sample contact, eliminating the multi-step amplification process required by PCR and reducing diagnosis time to minutes
Solution Approach 2:
The patent skips the time-consuming DNA amplification cycles of PCR by using direct binding detection. The field-effect transistor sensor directly detects biomarker-probe interactions without requiring iterative heating and cooling cycles, rushing through the diagnostic process in a single measurement step
3Measurement precision
If centralized lab processing is used, then diagnostic accuracy is improved, but ease of operation deteriorates due to logistics complexity
Solution Approach 1:
The patent segments the diagnostic process from centralized lab processing to decentralized point-of-care testing. By creating self-contained sensor devices with integrated detection capabilities, the system enables accurate diagnostics to be performed locally at patient sites, eliminating complex sample transportation and centralized processing logistics
Solution Approach 2:
The patent creates self-service diagnostic capabilities through autonomous sensor operation. The graphene transistors with functionalized surfaces perform detection automatically upon sample contact, requiring minimal operator intervention and enabling non-lab personnel to conduct accurate diagnostics locally without centralized lab infrastructure
4Measurement precision
If graphene transistors are functionalized with linkers and probe molecules, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent employs universal linker molecules that can bind to various probe types through common chemical mechanisms. This universal functionalization approach allows the same base platform to detect multiple different biomarkers by simply changing the probe molecule, reducing the complexity of creating specialized devices for each application
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 GFET sensor system provides rapid, reliable, and sensitive detection of biomarkers, suitable for point-of-care testing, with improved signal multiplexing and reduced device-to-device variations, facilitating fast and accurate diagnostics.
Implementation Method 1
When the biomarker of choice interacts with the probe molecule, they bind, producing a change in the electronic state of the probe and linker molecule. This produces a charge transfer into the graphene channel which changes its conductivity.
Implementation Method 2
The monolayer structure of graphene allows it to be sensitive to electrostatic perturbations at its surface.
Implementation Method 3
at least one gate electrode disposed at least in part at the center of the substrate, wherein, in use of the sensor, when a sample is deposited in contact with the gate electrode and the GFETs, the sample allows gating between the gate electrode and the GFETs. The sample may be a liquid sample, in which case the sample allows liquid gating between the gate electrode and the GFETs.
Data Source
AI summary
A sensor for performing measurements is disclosed. It comprises: a substrate; a plurality of graphene field-effect transistors (GFET) deposited on a central area of the substrate; at least one source electrode connected to the GFETs through at least one first metal track, wherein the at least one source electrode is disposed at the periphery of the substrate; at least one drain electrode connected to the GFETs through at least one second metal track, wherein the at least one drain electrode is disposed at the periphery of the substrate; and at least one gate electrode, disposed at least in part at the center of the substrate, wherein, in use of the sensor, when a sample is deposited in contact with the gate electrode and the GFETs, the sample allows gating between the gate electrode and the GFETs.