Extended Gate FET Biosensing for Cortisol Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cortisol monitoring technologies are bulky, expensive, time-consuming, and require training, limiting access to real-time, continuous monitoring and point-of-care testing, which is crucial for personalized diagnosis and treatment due to varying cortisol production levels throughout the day.
Innovation Solution
A biosensing system utilizing an extended gate field effect transistor (EGFET) with a synthetic biodetection layer on a conductive substrate, where an external electrode applies a gate voltage to modulate the source-drain characteristics, allowing for direct sensing of cortisol concentrations without exposing sensitive electronic components to corrosive environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional immunoassay chromatography or cyclic voltammetry systems are used to detect cortisol, then detection accuracy can be achieved, but the systems become bulky, expensive, and require training to operate
Solution Approach 1:
The patent replaces complex mechanical and electrochemical systems (immunoassay chromatography, cyclic voltammetry) with a field-effect transistor-based sensing system. The FET detects cortisol through electrical field interactions with the analyte, eliminating the need for bulky mechanical components, complex electrochemical cell assemblies, and associated training requirements while maintaining detection accuracy.
Solution Approach 2:
The invention changes the detection parameter from complex electrochemical measurements requiring specialized equipment to simple electrical field effects that can be measured with standard FET circuits. By monitoring changes in electrical parameters (current, voltage, capacitance) of the FET in response to cortisol binding, the system achieves accurate detection with simplified hardware.
2Measurement precision
If traditional laboratory systems are used for cortisol testing, then detection can be performed, but processing time is long and real-time monitoring is not available
Solution Approach 1:
The patent replaces time-consuming mechanical processes (sample preparation, chromatography separation, multiple measurement steps) with direct electrical field detection. The FET provides real-time signal output as cortisol binds to the sensing element, enabling immediate detection without lengthy processing intervals.
Solution Approach 2:
The invention enables continuous monitoring by maintaining the FET in an active sensing state where it continuously detects cortisol levels in real-time. Unlike batch processing methods that require repeated sample preparation and measurement cycles, the FET system provides uninterrupted detection, allowing patients to receive continuous feedback on their cortisol levels throughout the day.
3Productivity
If electronic components are directly exposed to sensing fluids, then direct detection is possible, but the components are damaged by corrosive environments
Solution Approach 1:
The patent divides the sensing system into distinct functional segments: a sensing element that contacts the corrosive fluid and contains the biodetection layer, and a protected FET component that remains isolated from the fluid. This segmentation allows the sensing function to be performed at the interface while the sensitive electronic components are shielded in a separate, protected zone, maintaining both detection speed and component durability.
Solution Approach 2:
The invention introduces an intermediary sensing element (the extended gate structure with biodetection layer) that mediates between the corrosive sensing fluid and the protected FET. This intermediary layer transduces the chemical interaction between cortisol and the biodetection layer into electrical signals that can be read by the FET without requiring direct contact between the fluid and the transistor components, thus protecting them from corrosion.
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 fast, label-free, and cost-effective real-time monitoring of cortisol levels, suitable for point-of-care applications, with a detection range from 1 pM to 100 nM, providing a portable and robust solution for continuous cortisol monitoring.
Implementation Method 1
The variations in the charge transfer from the external electrode to the gate electrode of the FET due to the presence of target molecules on the synthetic biodetection layer modulates the source to drain characteristics of the FET
Implementation Method 2
An external electrode can be dipped in the fluid and can then be connected to a power source supplying a voltage, which can be the gate voltage
Data Source
AI summary
Systems and methods for sensing analytes using an extended gate field effect transistor (EGFET) are provided. A biosensing system can utilize a biodetection layer on a substrate, which can be coupled to a field effect transistor (FET). The coupling can be such that the gate of the field effect transistor is connected to the substrate having the biodetection layer thereon. The functionalized substrate can include a well-defined area that can hold a specific, pre-determined volume of fluid on top of it. An external electrode can be dipped in the fluid and can then be connected to a power source supplying a gate voltage. The presence or concentration of the target analyte in the fluid can be determined based on the source-drain characteristics of the FET.