Holograms for Health

Responsive holograms that change color in the presence of certain compounds are being developed into portable medical tests and devices, which could be used to monitor conditions such as diabetes, cardiac function, infections, electrolyte or hormone imbalance easily and inexpensively. to test blood, breath, urine, saliva or tear fluid for a wide range of compounds, such as glucose, alcohol, hormones, drugs, or bacteria. When one of these compounds is present, the hologram changes color, potentially making the monitoring of various conditions as simple as checking the color of the hologram against a color gradient. Researchers from the University of Cambridge (United Kingdom) use a highly absorbent material known as a hydrogel, similar to contact lenses, impregnated with tiny particles of silver. Using a single laser pulse, the silver nanoparticles are formed into three-dimensional holograms of predetermined shapes in a fraction of a second.  When in the presence of certain compounds, the hydrogels either shrink or swell, causing the color of the hologram to change to any other color in the entire visible spectrum, the first time that this has been achieved in any hydrogel-based sensor.  A major advantage of the technology is that the holograms can be constructed in a fraction of a second, making the technology highly suitable for mass production. While these sorts of inexpensive, portable tests aren’t meant to replace a doctor, holograms could enable people to easily monitor their own health.