FET Biosensor Extended Gate Segmentation for pH Noise Cancellation
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Solution Overview
Problem
Existing FET-based biosensors face challenges in measuring target biomolecule signals due to interference from pH and ion concentration changes in sample solutions, leading to noise and reduced sensitivity.
Innovation Solution
A biosensor using an FET element with an extended gate electrode and sensing electrodes made of the same material, where a driving potential is applied to the sensing electrode through series connection with the solution and extended gate electrode, allowing for measurement of signal changes caused by target biomolecules while canceling out pH and ion concentration noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a general FET based biosensor is used for non-labeled/ultra-high sensitivity measurement, then sensitivity is improved, but noise due to pH and salt factors cannot be removed
Solution Approach 1:
The gate electrode is segmented into two separate electrodes: a reference gate electrode and a sensing gate electrode. The reference gate electrode measures pH and ion concentration effects, while the sensing gate electrode detects target biomolecule signals. By segmenting the gate function, the system can differentiate between noise sources and actual signals, resolving the contradiction between high sensitivity and noise removal.
Solution Approach 2:
The reference gate electrode acts as an intermediary that measures the environmental noise (pH and ion concentration) separately. This intermediary measurement allows the system to compensate for noise effects in the sensing electrode readings, enabling high sensitivity measurement while removing pH and salt interference.
2Measurement precision
If the surface charge density of the channel changes due to target substance binding, then signal detection capability is improved, but the signal is also affected by pH and ion concentration changes
Solution Approach 1:
The gate electrode is segmented into two separate electrodes: a reference gate electrode and a sensing gate electrode. The reference gate electrode measures pH and ion concentration effects, while the sensing gate electrode detects target biomolecule signals. By segmenting the gate function, the system can differentiate between noise sources and actual signals, resolving the contradiction between high sensitivity and noise removal.
Solution Approach 2:
The reference gate electrode provides feedback information about pH and ion concentration conditions to the signal processing system. This feedback allows for real-time compensation of environmental effects on the sensing electrode measurements, maintaining signal detection capability while eliminating pH and ion concentration interference through active noise cancellation.
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 precise measurement of target biomolecule signals without interference from pH and ion concentration changes, improving sensitivity and allowing for easy maintenance and reuse of the sensing module.
Implementation Method 1
the surface charge density of the channel changes as the target substance physically/chemically binds to the receiving substance (receptor) resulting in a change in a semiconductor inversion layer or Schottky barrier, thereby causing a change in the channel current which is to be measure
Implementation Method 2
a driving potential is applied to the sensing electrode to pass through the solution and the extended gate electrode and transferred to the gate electrode of the FET element
Data Source
AI summary
A bio sensor using a FET element and an extended gate, and an operating method thereof are disclosed. A biosensor using a field effect transistor (FET) device and an extended gate electrode according to the present invention is characterized by comprising: an extended gate electrode connected to the FET element; a sensing electrode made of the same material as the extended gate electrode and on which a receptor antibody selectively recognizing a target molecule is fixed; and a reference electrode that maintains a constant potential and is selectively connected to the sensing electrode.