Nanowire System Detects Biowarfare Agents

A new barcode system based on biosensing nanowires can help to detect biowarfare agents in the field. The system can also be used to detect victims of an infectious disease outbreak.

Lawrence Livermore National Laboratory (LLNL, Livermore, CA, USA) researchers built submicrometer layers of different metals including gold, silver and nickel that act as "barcodes” for detecting a variety of pathogens and toxins including anthrax, smallpox, ricin, and botulinum. The researchers were led by Dr. Jeffrey Tok of LLNL's biosecurity and nanosciences laboratory. The system was described in the August 4, 2006, online international journal Angewandte Chemie.

The team, which included researchers from Stanford University (Stanford, CA, USA), the University of California-Davis Center for Biophotonics (Sacramento, CA, USA), and Nanoplex Technologies (Mountain View, CA, USA), used the multi-striped metallic nanowires in a suspended format to rapidly identify sensitive single and multiplex immunoassays that simulated biowarfare agents. They produced nanoscale wires by electrochemically depositing metals within the tiny cavities of porous mineral solids.

They then layered the gold and silver in a specific way to produce nanowires with different characteristic stripe patterns depending on which pathogen they were trying to identify. The nanowires have dimensions of ~6.0 µm length and ~0.25 µm. diameter. The reflection pattern and fluorescence from each stripe sequence is clearly recognizable, similar to a barcode on a retail product.

"Antibodies of specific pathogens have been attached to the wires,” said Dr. Tok, "This produces a small, reliable, sensitive detection system that can easily be taken into the field.”



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