Hair

Researchers at The University Of New Mexico believe they have developed a way to etch your hair so that it reflects light to show almost any color you wish. While still being developed (the above image is a mockup from the project), they have been able to use an ion beam to etch stands of hair with nano patterns. These patterns then reflect light in such a way that hair appears to be colored. The etching process is permanent (until your hair grows out), but the researchers hope to develop a polymer based conditioner that would allow the color effect to be easily washed out. This process is definitely not even close to hitting the streets, but it is interesting none the less. To find out more, the process is detailed in The Journal Of Cosmetics Dermatological Sciences And Applications.