Nanopore Sensing

Nanopore fabrication
A nanopore is, essentially, a nano-scale hole. This hole may be:
• Biological: formed by a pore-forming protein in a membrane such as a lipid bilayer
• Solid-state: formed in synthetic materials such as silicon nitride or graphene
• Hybrid: formed by a pore-forming protein set in synthetic material
New generation of sequencing technology uses nanopores to deliver ultra long read length single molecule sequence data, at competitive accuracy, on scalable electronicGridION platform. Miniaturised version of technology, MinION, will make nanopore sequencing universally accessible. The UK firm Oxford Nanopore built the device, called MinION, and claims it can sequence simple genomes – like those of some viruses and bacteria – in a matter of seconds. More complex genomes would take longer, but MinION could also be useful for obtaining quick results in sequencing DNA from cells in a biopsy to look for cancer, for example, or to determine the genetic identity of bone fragments at an archaeological dig.

Nanopore sensing
A nanopore may be used to identify a target analyte as follows.

This diagram shows a protein nanopore set in an electrically resistant membrane bilayer. An ionic current is passed through the nanopore by setting a voltage across this membrane.
If an analyte passes through the pore or near its aperture, this event creates a characteristic disruption in current. By measuring that current it is possible to identify the molecule in question. For example, this system can be used to distinguish the four standard DNA bases and G, A, T and C, and also modified bases. It can be used to identify target proteins, small molecules, or to gain rich molecular information for example to distinguish the enantiomers of ibuprofen or molecular binding dynamics. In this we have two devices : GridION and MinION

The GridION system
Oxford Nanopore's proprietary nanopore-based sensing chemistries are operated on an electronics-based platform, the GridION system. This enables the scaled-up measurements of multiple nanopores and the sensing, processing and analysis of data in real time.
A single instrument, a GridION node, operates with a single-use cartridge that contains the necessary reagents to perform an experiment.
A node can be employed as a single desktop instrument, or scaled up in a similar way to computing installations.
As a desktop instrument for the individual researcher, it can write data to the network or a locally attached disc (directly through a USB or through a network) and work in a small lab.
Each node is a network device and multiple nodes can be aggregated together into larger co-operating units or clusters, communicating with each other in a peer-to-peer fashion over the user's network. The system is designed to interface, or even co-locate, with standard or high-performance IT infrastructure. Workflow overheads, and total costs, including IT, scale linearly with the

GridION system.
Graphic: a single node (left) may be used as a desktop device, or installed in conjunction with other nodes that communicate with each other through a network (centre, right).
Use of the GridION platform in Personalized Healthcare
The GridION platform is an electronic analysis system that can be tailored for the analysis of DNA, RNA, protein and other analytes. This novel technology has applications across personalized healthcare. This may include the analysis of a patient's DNA, discovery and validation of new protein biomarkers or an electronic diagnostic test for discovered biomarkers.

The GridION and MinION systems are appropriate for use in security/defense across a variety of applications. When used for DNA sequencing, the unique workflow is well suited to the rapid identification of organisms such as pathogens. Nanopores may be adapted for the identification of small molecules. This may include biologically active molecules such as controlled drugs, synthetic compounds such as toxins or explosives.

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  • Rajdeep Janorkar

    Nanopore Sensing 5 months ago