Holograms As Smart Labels Poised To Reveal Bio Data

Biosensors evoke images of tiny chips and wireless technology, but the next generation of biosensors may be: holograms costing only fractions of a cent, and the technology could usher in an era of "smart labels" that show when food is spoiled or when body glucose and alcohol levels are too high.Prototypes developed include contact lenses that monitor glucose levels, thin badges that detect alcohol levels, and sticks that can tell, instantly, if milk has spoiled or become contaminated. The technology promises to be quicker and cheaper than tests used today and can be deployed with minimal training.. A test showing that fuel has been contaminated with trace amounts of water reads "dry" or "wet." In a breath alcohol test intended for police offices, suspects breathe onto tiny cards that either show a green automobile or a red X, establishing whether a person is sober enough to drive.
The holograms can detect pH to four decimal places and chemical concentrations of hormones and other biologically important substances. The samples tested do not need to be pure: The holograms can work in milk or even in stool samples from newborns, said Chris Lowe, a professor at Cambridge University. The image that appears on the hologram is caused by silver particles on a "smart polymer," a lightweight material similar to everyday plastic. These polymers can be designed to change shape in different chemical environments. This shape change moves bands of silver particles, and patterns of silver particles control the brightness and color of the hologram. Thus, the hologram can be used to display a message, a numerical scale or other readout. Here is a related article explaining usage of hologram with laser diode.