Technology that allows sodium and blood oxygen levels to be monitored with an iPhone via a nanosensor “tattoo” is being developed by a team at Northeastern University’s Department of Pharmaceutical Sciences. The project began as a way to check blood glucose levels in diabetics without the need for finger-prick bloodletting. A solution containing certain nanoparticles is injected into the skin; these nano particles fluoresce when exposed to a target molecule (in this study, that includes glucose and sodium). An iPhone inside a modified case is then pressed to the skin and tracks changes in the level of fluorescence, which then reveal the amount of sodium or glucose present. Currently, the iPhone only takes images of the tattoo, which are then analyzed on a computer. The team has plans to create an iPhone app which would allow analysis on the phone.