chemFET Arrays for Low-Buffer Hydrogen Ion Sequencing Detection
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Solution Overview
Problem
Conventional ISFET arrays face challenges in achieving high signal linearity and sensitivity for hydrogen ion detection during nucleic acid synthesis reactions, particularly due to sequestration of hydrogen ions by buffering components, which reduces the detectable signal.
Innovation Solution
The use of chemFET arrays with reduced buffering capacity in the reaction solution or chamber, and techniques such as nick translation reactions to amplify hydrogen ion release, allowing for increased detection of hydrogen ions during nucleic acid synthesis reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If buffering components are added to the reaction solution to maintain pH stability, then pH stability is improved, but hydrogen ion detection sensitivity deteriorates due to sequestration of hydrogen ions
Solution Approach 1:
The patent extracts hydrogen ions from the bulk solution by using them as the primary detection target in real-time sequencing reactions. By focusing detection on the hydrogen ions released during nucleotide incorporation rather than measuring bulk pH, the system achieves both sensitivity and functional pH stability without requiring traditional buffering components
Solution Approach 2:
The patent changes the detection parameter from bulk pH measurement to real-time hydrogen ion concentration measurement during nucleotide incorporation. This parameter change allows detection of transient hydrogen ion releases without requiring the solution to maintain stable pH, thereby resolving the contradiction between pH stability and detection sensitivity
2Ease of manufacture
If conventional ISFET arrays are used for hydrogen ion detection, then device fabrication is simplified, but signal linearity and detection sensitivity are insufficient for nucleic acid synthesis reactions
Solution Approach 1:
The patent employs chemFETs with specialized chemical sensing membranes that combine the ease of semiconductor fabrication with enhanced chemical sensitivity. These composite structures integrate conventional FET fabrication with specialized sensing layers designed for high-affinity hydrogen ion detection, achieving both manufacturing simplicity and superior detection performance
Solution Approach 2:
The patent optimizes the electrical and chemical parameters of the FET devices, including gate oxide thickness, channel dimensions, and membrane composition, to enhance signal linearity and sensitivity specifically for nucleic acid synthesis detection while maintaining compatibility with standard fabrication processes
3Stability of the object's composition
If buffering capacity is increased to stabilize the reaction environment, then reaction stability is improved, but the signal-to-noise ratio for hydrogen ion detection deteriorates
Solution Approach 1:
The patent extracts and isolates the hydrogen ion detection signal from the bulk reaction environment by using specialized chemFET sensors. This extraction allows the system to detect hydrogen ions released during nucleotide incorporation without the signal being masked by buffering components, achieving high signal-to-noise ratio while maintaining reaction stability
Solution Approach 2:
The patent introduces chemFET sensors as intermediary devices between the reaction environment and the detection system. These sensors act as mediators that selectively respond to hydrogen ions while being insensitive to other buffering components, thereby resolving the contradiction between reaction stability and detection sensitivity
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 enhances the signal-to-noise ratio by maximizing the detection of hydrogen ions released during nucleic acid synthesis, improving the accuracy and efficiency of nucleic acid sequencing.
Implementation Method 1
ISFETs conventionally have been explored, primarily in the academic and research community, to facilitate measurement of the hydrogen ion concentration of a solution (commonly denoted as 'pH'). An ISFET is an impedance transformation device that operates in a manner similar to that of a MOSFET and is particularly configured to selectively measure ion activity in a solution
Implementation Method 2
techniques such as nick translation reactions to amplify hydrogen ion release, allowing for increased detection of hydrogen ions during nucleic acid synthesis reactions
Data Source
AI summary
Methods and apparatus relating to FET arrays for monitoring chemical and/or biological reactions such as nucleic acid sequencing-by-synthesis reactions. Some methods provided herein relate to improving signal (and also signal to noise ratio) from released hydrogen ions during nucleic acid sequencing reactions.