Fluidic FET Sensing Chip for Low-Noise Concentration Detection
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Solution Overview
Problem
Existing biosensors face challenges in large-scale integration, limited detection area, noise interference, and the need for specialized processes, limiting their ability to detect bacteria, viruses, and suspended particles accurately and efficiently.
Innovation Solution
A sensing chip with a fluidic device designed using CMOS process, incorporating a field effect transistor and a fluidic device with a second gate electrode and metal layer receptors, capable of detecting and measuring concentration by capturing target objects with temperature control and voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-sensitivity nanowires are designed in the chip method, then detection sensitivity is improved, but noise interference increases causing misjudgment
Solution Approach 1:
The patent introduces a receptor layer as an intermediary between the nanowire sensor and target objects. The receptor specifically binds to target objects (bacteria, viruses, particles) before they interact with the nanowire, acting as a mediator that filters out non-specific noise while allowing specific target detection. This resolves the contradiction by maintaining high sensitivity through nanowire-noreceptor interaction while reducing noise through selective binding.
Solution Approach 2:
The patent modifies the surface properties of the nanowire by coating it with receptors and controlling the electrical parameters (voltage, current) during detection. By changing the electrical parameters and surface chemistry parameters, the system achieves high sensitivity detection while minimizing noise interference through optimized detection conditions.
2Measurement precision
If polycrystalline silicon of the nanowire is exposed outside, then a special process is required, but wafer foundries are unwilling to provide special processes reducing yield
Solution Approach 1:
The patent designs the nanowire structure to be compatible with standard CMOS fabrication processes used in commercial wafer foundries. The nanowire is integrated within the existing transistor structure, allowing it to serve multiple functions (sensing and standard circuit operation) using universal manufacturing processes. This eliminates the need for special customized processes while maintaining detection capability.
Solution Approach 2:
The patent merges the sensing function with the standard transistor structure by integrating the nanowire as the channel region of a field-effect transistor. This combination allows the nanowire to function both as a sensitive detector and as part of a standard semiconductor device that can be manufactured using conventional CMOS processes in commercial foundries.
3Measurement precision
If the detection area is limited, then the concentration of target objects cannot be estimated, but increasing detection area increases device complexity
Solution Approach 1:
The patent transitions from a two-dimensional surface detection approach to a three-dimensional volume detection approach by creating a fluidic chamber that suspends target objects in three-dimensional space above the nanowire array. This dimensional change increases the effective detection volume and enables concentration estimation without proportionally increasing the chip footprint or device complexity.
Solution Approach 2:
The patent divides the detection area into multiple independent sensing regions with separate nanowire-receptor units. Each segment can detect target objects independently, and by aggregating signals from multiple segments, the system achieves concentration measurement capability while maintaining manageable device complexity through modular design.
4Measurement precision
If PCR is used for detection, then long detection reaction time or labeling is required, but this cannot be popularized due to expensive equipment
Solution Approach 1:
The patent replaces the complex thermal cycling mechanism of PCR with a direct electrical detection mechanism using field-effect transistors. Instead of requiring repeated heating and cooling cycles for DNA amplification, the system directly detects target objects through electrical signal changes when they bind to receptors on the nanowire, eliminating the need for expensive thermal cyclers and reducing detection time.
Solution Approach 2:
The patent employs receptors that automatically and specifically bind to target objects upon contact, eliminating the need for external amplification steps or labeling procedures. The binding event itself generates a detectable electrical signal, allowing the system to perform detection without requiring complex external equipment or lengthy reaction protocols.
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 chip enhances detection accuracy and sensitivity by measuring concentration and type of target objects, such as bacteria and viruses, while being compatible with standard semiconductor processes, reducing noise interference and improving yield.
Implementation Method 1
the field effect transistor having a first gate electrode, a source electrode, and a drain electrode, and the first gate electrode is arranged between the source electrode and the drain electrode
Implementation Method 2
a temperature control unit provides a temperature control signal to the sensing chip with fluidic device to heat and control the temperature of the sample on the sensing chip with fluidic device, so the kinetic energy or change decomposition of the target object(s) in the sample may be increased due to the temperature rise
Implementation Method 3
a plurality of receptors on the metal layer is provided for capturing a plurality of target objects in the sample
Data Source
AI summary
A sensing chip with fluidic device includes a substrate with a first area and a second area, a field effect transistor is arranged in the second area of the substrate and is electrically connected with the field effect transistor. The fluidic device includes an insulation layer with a window to expose the surface of substrate in the second area. A second gate electrode is arranged in the window of the isolation layer on the second area of the substrate. The sample is placed in the fluidic device to contact with the second gate electrode, and the receptor(s) on the metal layer will capture the target object in the sample, so the voltage of the metal layer will change with amount of the target object captured by the receptor(s). Thus, the concentration of the target object(s) in the sample may obtain by the changes of the voltage of the metal layer.