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March 27th, 2008

Identifying bacteria with gold-nanoparticle constructs

Abstract:
Bacteria cause millions to suffer from a variety of infections every year. Current methods of identifying bacteria require expensive equipment or a great deal of time—the most common method for identifying bacteria, plating and culturing, requires at least 24 hours. A quicker method of identifying harmful bacteria would be beneficial to many fields, including medical diagnosis and food inspection.

Chemists have devised a sensor array to identify bacteria by fluorescence. The general design involves associating a negatively charged conjugated polymer with positively charged chemicals on the surface of a gold nanoparticle. The negatively charged conjugated polymer is fluorescent on its own but, when it's associated with the nanoparticle, the fluorescence is quenched. Bacteria, which have negatively charged surfaces, can dissociate the conjugated polymer. Once the conjugated polymer has been freed, the fluorescence is restored. Different bacteria species may or may not trigger this reaction depending on the type of chemicals used on the surface of the gold nanoparticle.

Source:
arstechnica.com

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