Article Abstracts | March 2008
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Food and Water Safety
Silicon photonic wire waveguide sensors detect the presence of pathogens and chemicals.
by Siegfried Janz, National Research Council of Canada
Molecular sensors can detect trace amounts of molecules present in food and water that signal the presence of danger to humans. The target may be the toxic molecule itself, as in the case of pesticide residues and pollutants, or it may be a biomarker molecule — such as DNA or an antigen — that is associated with pathogenic organisms.
The ideal sensor should detect the lowest possible level of toxin and should register a highly specific response to minimize the possibility of false negative readings, which can be disastrous. The device also should minimize false positives that might trigger needless and expensive countermeasures. To reduce test time and cost, transduction methods requiring a minimum of sample processing should be used — hence the strong interest in direct label-free detection, which requires no prior attachment of fluorescent or other tags to the sample molecules...
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