Portable DNA Sequencing With Graphene Sensors and Carbon Nanotubes
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Solution Overview
Problem
Current DNA sequencing technologies face limitations such as high cost, low accuracy, and instability of nanopores, as well as challenges in stabilizing DNA strands during sequencing, leading to background noise and limited spatial resolution.
Innovation Solution
A DNA sequencing system using carbon nanotube hybrids and graphene sensors, where single-stranded DNA is wrapped around carbon nanotubes and translocated through a nanofluidic chip with graphene sensors, allowing for stable electrical current measurement to determine base composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If protein nanopores are used for DNA sequencing, then sequencing can be performed with high accuracy, but the nanopores have very short shelf life and require expensive reagents
Solution Approach 1:
The patent uses disposable microchips with solid-state nanopores instead of reusable protein nanopores. The solid-state nanopores are fabricated from stable materials like silicon that can be mass-produced at low cost and have long shelf lives, eliminating the need for expensive reagents and maintaining reliability while preserving sequencing accuracy
Solution Approach 2:
The patent employs composite material structures including DNA-carbon nanotube hybrids and graphene sensors. The carbon nanotubes provide structural stability and electrical conductivity, while the graphene sensors detect DNA bases with high precision. This composite approach combines the advantages of different materials to achieve both accuracy and reliability
2Reliability
If solid-state nanopores are used to manufacture enzyme-free nanopores, then shelf life is improved, but DNA strands become unstable during translocation causing large background noise
Solution Approach 1:
The patent introduces carbon nanotubes as intermediary structures that wrap around DNA strands. These carbon nanotube-DNA hybrids serve as mediators that stabilize the DNA during translocation through the solid-state nanopore, reducing motion-induced background noise while maintaining the stability advantages of solid-state nanopores
Solution Approach 2:
The patent modifies the physical and chemical parameters of the DNA structure by forming hybrid structures with carbon nanotubes. This changes the mechanical properties of the DNA strand, making it more stable during translocation and reducing signal noise while maintaining sequencing accuracy
3Ease of manufacture
If solid-state nanopores are used for sequencing, then manufacturing cost is reduced, but surface area is limited preventing inclusion of sophisticated sensors
Solution Approach 1:
The patent transitions from two-dimensional nanopore structures to three-dimensional carbon nanotube hybrid structures. The carbon nanotubes provide additional spatial dimensions for sensor placement, allowing sophisticated graphene sensors to be positioned along the translocation path without increasing the footprint of the nanopore structure itself
Solution Approach 2:
The patent divides the sensing function into multiple segmented graphene sensors positioned at different locations along the nanotube-DNA hybrid structure. This segmentation allows multiple sensors to detect different aspects of the DNA translocation event, providing sophisticated base sequence resolution while maintaining a compact overall structure
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 reduces motion-induced background noise, increases spatial resolution, and enhances sequencing accuracy while being more cost-effective and stable than existing systems.
Implementation Method 1
A power source applies a constant voltage to the graphene sensors between the opposing electrodes. The resulting electrical current through the graphene sensors between the opposing electrodes is measured
Implementation Method 2
DNA strands are pulled through the nanopores by electrophoresis
Data Source
AI summary
A method of sequencing DNA is disclosed. A single-stranded DNA molecule is wrapped around a carbon nanotube to form a DNA/carbon nanotube hybrid structure. The DNA/carbon nanotube hybrid structure is then moved across a nanofluidic chip. The nanofluidic chip includes graphene sensors and a nanochannel extending across the graphene sensors. The graphene sensors are positioned between opposing electrodes. A power source applies a constant voltage to the graphene sensors between the electrodes. The electrical current through the graphene sensors between the electrodes is measured as the DNA/carbon nanotube hybrid structure moves across the graphene sensors. The composition of the bases of the single-stranded DNA molecule is determined based on the measured electrical current.