For all tattoo lovers, this is like finding the holy grail of tattoos. Imagine if your tattoos could change colour as per your body conditions and keeps track of all your vitals in your body? This is no longer a thesis. Researchers are working very hard at MIT and Harvard University to develop bio-sensitive tattoo ink that will change colour in response to dehydration or odd sugar levels in your blood. Moreover, these are temporary tattoos, so it has no real time negative aspect like other permanent tattoos has. It can be used as a health monitor for patients suffering from chronic diseases. It can also be beneficial for astronauts to monitor their well being when they are in space. These smart tattoos can also be very useful for athletes, to watch their body conditions.