nano 2007-10-24 10:55
Functionalized nanotubes monitor viruses
[size=5][b]Functionalized nanotubes monitor viruses[/b][/size]
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[b]【纳米科技世界快讯】Carbon nanotubes have taken another step towards becoming fast-acting biosensors thanks to the work of 11 scientists based in the US. The team has come up with the first evidence of straightforward, ambient covalent immobilization of a viral ligand-receptor-protein system onto individual and bundled, single-walled carbon nanotubes (SWNTs).[/b]
[img]http://img137.imageshack.us/img137/2678/0610521fd0744uf7.jpg[/img]
[i]Optical (top) and corresponding fluorescence (bottom) images of fluorescently labeled Ad 12 Knob targeting CAR-functionalised air-oxidized SWNTs. The scale bar represents 2.5 microns. (Credit: Stanislaus Wong)[/i]
The result allows researchers to biofunctionalize SWNTs so that specific viruses will bind to the structure. Furthermore, the covalent nature of the functionalization means that the receptor proteins are able to resist extended washing and remain immobilized on the surface of the carbon nanotube.
"Robustness and cyclability are key issues," Stanislaus Wong of the State University of New York at Stony Brook told nanotechweb.org. "Maintaining biological activity over long periods of time is one of the major challenges in this area."
[img]http://img152.imageshack.us/img152/7592/0610522fe4b4dwh4.jpg[/img]
[i]Molecular dynamics simulation of the CAR protein covalently attached to the carbon nanotube. (Credit: Robert Johnson and A.T. Charlie Johnson)[/i]
To exploit the effect, the group fabricated a series of field effect transistors (FETs) based on the functionalized structures and exposed the devices to a complementary adenovirus known as the Ad 12 Knob virus (note – adenoviruses are one of many subclasses of virus that cause infections such as the common cold and other ailments affecting the upper-respiratory and gastrointestinal tracts).
The target protein was absorbed by the FET, modifying the current-voltage (I–V) characteristics of the device and providing a simple means of detecting the virus. When exposed to a non-specific (noncomplementary) protein, the I–V characteristics of the FET remained unchanged.
According to the group, the methodology can be extended to reveal the presence of serotype12 and all other possible CAR-binding adenoviruses, as well as subgroup B Coxsackie viruses. In other words, the researchers have found a model system.
The project was a joint effort between research groups at the State University of New York at Stony Brook, Brookhaven National Laboratory and the University of Pennsylvania.
The researchers reported their work in [url=http://pubs.acs.org/cgi-bin/abstract.cgi/nalefd/2007/7/i10/abs/nl071572l.html][color=#0000ff][i]Nano Lett[/i]. [b]7[/b] 3086[/color][/url].
Source: nanotechweb.org.