Unless you're a True Blood diehard, the idea of bleeding yourself intentionally shouldn't really seem all that appealing. So imagine how most diabetics feel when they're forced to prick their thumbs three times a day in the name of health. Well, soon they might not have to thanks to a nanosensor tattoo and... an iPhone? Developed by Prof. Heather Clark and her Northeastern University team, this injection of subdermal nanoparticles combines "fluorescent dye, specialized sensor molecules...and a charge-neutralizing molecule" that attach to glucose, releasing ions and altering the tat's glow in the process. The researchers had originally designed a "large boxlike" tattoo-reading device, but an apparent Apple fanboy on the team modded an iPhone case with LEDs and a filter lens to make the whole affair a bit more stylish. Next up for the team is, you guessed it, an app for that -- although this one'll focus on sodium.