Pathogen identification is an important process in control and eradication. At present, to identify a variety of them such as biological weapons, bacteria such as anthrax, a virus such as smallpox, or a toxin such as botulism, samples must be collected and cultured in controlled laboratories. A new system has been developed using nanowire sensors which is very compact and works virtually instantaneously.
Mechanism
The core of this portable bio weapon recognition system is an amalgamation of tiny wires, which are about 250 nanometers around and 6,000 nanometers long and assortment of antibodies, the proteins that the body produces to directly attack, or direct the immune system to attack, cells that viruses, bacteria, and other unpleasant intruders infect.
Construction
Each type of pathogen calls for a unique antibody. The tiny wires made by an independent company are electrochemically formed and then layered with bands of silver, gold, and nickel to produce patterns that are similar to the ubiquitous barcodes found on products worldwide. Then antibodies are essentially glued to the miniscule wires.
For example, say anthrax antibodies are attached to nanowires with one code and smallpox antibodies are attached to nanowires with another forming a pool of various striped nanowires each of which will have a unique antibody assigned to it for the detection of particular pathogen.
Working
To identify pathogens, millions of bar-coded, antibody-carrying nanowires are floated in a neutral liquid called an assay buffer, into which samples of suspected pathogens are injected. If a pathogen meets its corresponding antibodies, they will join creating nanowires, antibody, antigen sandwich that will fluoresce, or glow, under a special light. To identify individual pathogens, the system takes two digital mug shots in quick succession. In the first the special light is off, and the barcodes are visible. In the second the light is on and the pathogen-fingering nanowires are glowing. A computer then matches each glowing wire in the second photo to its barcode. The advantage of the system is that many kinds of bar-coded antibodies can be mixed together in the assay buffer liquid and can be reused.