Wednesday, June 30, 2010

Carbon Nanotube Wearable Bio-Smoke Alarm Detects World's Deadliest Chemicals, Diseases and Warfare Agents Say LLNL Scientists

Lawrence Livermore National Security, LLC (Livermore, CA) received U.S. Patent 7,745,856 for a carbon nanotube microfluidic "bio-smoke alarm" that can detect and protect against some of the world’s deadliest substances. 

The carbon nanotube “bio-smoke alarm” combines carbon nanotubes and microfluidics to make a chemical/bio sensor that can detect radioactive substances as well as a full spectrum of biowarfare agents including bacteria, viruses and toxins, examples of which include Anthrax, Smallpox, Plague, Botulism, Tularemia, and Viral hemorrhagic fever. The agents can also include a full spectrum of health related agents including bacteria, viruses and toxins, examples of which include SARS and avian flu.  The sensor was developed by Lawrence Livermore National Laboratory scientists.

Microphotograph of a Gram stain of the bacterium Bacillus anthracis, the cause of the anthrax disease
Image credit: Wikipedia

Nanowires and nanotubes provide a critical enabling technology for chem/bio sensing. Their surface-to-volume ratio is phenomenally high; therefore, surface events such as binding of a protein or an ion can trigger a significant change in bulk electronic properties and enable electrical detection of binding events, according to inventors Aleksandr Noy,  Olgica Bakajin, Sonia Letant, Michael Stadermann,  and Alexander B. Artyukhin

Microfluidics is a multidisciplinary field comprising physics, chemistry, engineering, and biotechnology that studies the behavior of fluids at the microscale and mesoscale, that is, fluids at volumes thousands of times smaller than a common droplet. It is a new science, having emerged only in the 1990s, so the number of applications for this technology is currently small. However, it is potentially significant in a wide range of technologies. Microfluidics is used in the development of DNA microarray technology, micro-thermal and micro-propulsion technologies, and lab-on-a-chip technology.

Microfluidics also concerns the design of systems in which such small volumes of fluids will be used. The behavior of fluids at the microscale can differ from `macrofluidic` behavior in that factors such as surface tension, energy dissipation, and electrokinetics start to dominate the system. Microfluidics studies how these behaviors change, and how they can be worked around, or exploited for new uses. A microfluidic device can be identified by the fact that it has one or more channels with at least one dimension less than 1 mm.

The invention provides a sensor apparatus comprising a nanotube or nanowire, a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer. The present invention also provides a biosensor apparatus comprising a gate electrode; a source electrode; a drain electrode; a nanotube or nanowire operatively connected to the gate electrode, the source electrode, and the drain electrode; a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer.

The lipid bilayer nanotube or nanowire sensor can detect variations in ion transport through a protein pore using the lipid bilayer nanotube or nanowire sensor. The lipid bilayer nanotube or nanowire biosensor provide superior detection efficiency by using signal amplification, and also permit straightforward integration and multiplexing. The lipid bilayer nanotube or nanowire biosensor also provide a large amount of flexibility allowing seamless integration with different types of membrane-based sensing agents. The lipid bilayer nanotube or nanowire sensor and the biosensor device feature high selectivity, low cost and low power consumption, and can serve as a wearable "bio-smoke alarm." 

Single-wall nanotubes are grown on TEM grids using catalytic CVD synthesis to produce suspended carbon nanotubes suitable for modification process. The polymer coating is formed on these suspended carbon nanotubes by exposing them to the alternating solutions of polyanions and polycations by layer-by-layer assembly. The lipid bilayer is formed by vesicle fusion. Additional exposure to the solution of an agent results in pore insertion and the formation of the protein pore in the bilayer membrane. 

1 comment:

  1. I would like to say thank you for spending more time and effort to share this very nice and wonderful topic with us. I am sure your idea is more helpful for me.

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