For diabetics, checking blood glucose levels is literally a pain. Current blood glucose meters require a prick of the finger to get a small blood sample that is then put onto a small paper strip, inserted into the meter, and analyzed. The strips are a recurring cost to diabetics, and the constant finger pricks can be a route for infection. Now a research team at Northeastern University has developed a method of reading blood glucose levels with an iPhone and a nanosensor tattoo.
The team's method works this way: they inject a patient with subdermal nanoparticles containing "fluorescent dye, specialized sensor molecules...and a charge-neutralizing molecule." The molecules attach to glucose, release ions, and alter the glow of the nanosensor tattoo based on the relative amount of glucose.
While the initial device for reading the tattoo's glow was a big ugly box, one of the team members apparently outfitted an iPhone case with LEDs and filters to do the job. According to our sister site Engadget, the team is also looking at a way to measure blood sodium (associated with dehydration) and oxygen levels with iPhones and apps. You never thought that your iPhone would be an early-generation medical tricorder, did you?
Update: Since a few commenters asked, this is an experimental device and has not (to our knowledge) been submitted to the FDA for their lengthy approval process.