A new type of barcode is too small to see with the naked eye, yet it holds big promise for biomedical research, law enforcement, and everyday life, say researchers.
The fluorescent tagging devices are short glass ribbons just 100 micrometers long and 20 m wide. They contain stripes reminiscent of the black-and-white barcodes on milk cartons or cereal boxes, but these new barcodes tag large biomolecules, such as DNA. The labels become visible under a microscope when they're hit with a wavelength of light that makes them fluoresce.
Other researchers have created molecular tags from fluorescing particles called quantum dots (SN: 7/7/01,
p. 7: Wee dots yield rainbow of molecule markers) or tiny metallic bars overlaid with a sequence of precious-metal stripes, inc