Single Molecule Processing Apparatus Aperture Manufacturing
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Solution Overview
Problem
Existing methods for processing single molecules, such as DNA sequencing, face challenges due to the high electrical conductivity of graphene layers, which makes it difficult to detect small conductivity changes induced by molecules, and the mechanical robustness and orientation issues of free graphene layers.
Innovation Solution
A manufacturing method involving a self-assembling resist to create apertures in a processing layer, allowing for the reliable processing of single molecules by generating small apertures suitable for nanometer-sized structures, and using a crossed-slit device with graphene layers for improved mechanical stability and orientation, enabling efficient DNA sequencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a graphene layer is used for molecular sensing, then the sensor can detect molecular passage, but the high electrical conductivity of graphene makes it difficult to detect small conductivity changes induced by molecules
Solution Approach 1:
The patent divides the sensing function into two separate components: a graphene layer for mechanical support and aperture formation, and a distinct conductive layer (such as metal or doped semiconductor) for electrical signal detection. This segmentation allows each layer to optimize its specific function without the conflicting requirements of high conductivity and low background noise that plague single-layer graphene sensors.
Solution Approach 2:
The patent employs a composite structure combining graphene with other materials having complementary properties. The graphene provides mechanical strength, chemical stability, and nanometer-scale aperture formation, while the added conductive layer provides the necessary electrical conductivity for sensitive detection. This composite approach resolves the contradiction by integrating materials that excel at different functions.
2Reliability
If free graphene layers are used in the apparatus, then the apparatus can process single molecules, but the mechanical robustness is poor
Solution Approach 1:
The patent merges the free-standing graphene layer with a solid substrate (such as silicon dioxide or silicon nitride). The graphene is transferred onto or integrated with the substrate, which provides the necessary mechanical support and robustness. This combination maintains the beneficial properties of graphene while eliminating its mechanical fragility when used in isolation.
Solution Approach 2:
The patent utilizes the graphene layer as a thin film deposited on a rigid substrate. The graphene acts as a flexible but extremely thin coating that provides chemical stability and enables precise aperture formation, while the underlying substrate provides the mechanical robustness. This thin-film approach maintains molecular access to the sensing region while ensuring structural integrity.
3Ease of operation
If a long gap between graphene layers is used, then molecules can pass through, but the molecules adopt many different orientations and configurations making interpretation difficult
Solution Approach 1:
The patent creates a localized constriction or narrowing in the gap region where the sensing occurs. While the overall gap may be sufficient for molecule passage, the local geometry at the sensing zone is optimized to constrain molecular orientation. This local quality change ensures that molecules pass through in a controlled manner at the critical detection point, improving measurement precision without compromising overall molecule passage.
Solution Approach 2:
The patent employs curved or tapered aperture geometries rather than simple parallel plates. The curved surfaces guide molecules through the gap in a controlled trajectory, reducing the variety of orientations and configurations. The spherical or conical shaping of the aperture region helps funnel molecules into a more uniform passage path, improving the interpretability of measurement results.
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 method allows for the reliable processing and sequencing of single molecules by generating small apertures with high spatial density, enhancing mechanical stability and reducing shunt currents, thereby improving the detection of conductivity changes and achieving single-base resolution in DNA sequencing.
Implementation Method 1
a material shall have the feature to self-assemble into a pattern of (at least) two different regions of different (chemical and/or physical) composition
Data Source
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AI summary
The invention relates to a method for manufacturing an apparatus for the processing of single molecules. According to this method, a self-assembling resist (155) is deposited on a processing layer (110, PL) and allowed to self-assemble into a pattern of two phases (155a, 155b). One of these phases (155a) is then selectively removed, and at least one aperture is generated in the processing layer (110, PL) through the mask of the remaining resist (155b). Thus apertures of small size can readily be produced that allow for the processing of single molecules (M), for example in DNA sequencing.