iPhone helps 'combat' diabetes, anemia

Chalk up another potential medical application for Apple Inc.’s iPhone: a modified version of the popular gadget can help monitor sodium and glucose levels to combat diabetes and anemia. A team from Northeastern University’s Department of Pharmaceutical Sciences led by Professor Heather Clark worked on the system, that also involves a nanosensor "tattoo". “I don’t think there’s any doubt that this sort of technology will catch on," Jim Burns, head of drug and biomedical research and development at Genzyme, said in an article posted on the MIT Technology Review. The system could be used to track many important biomarkers besides glucose and sodium, in a simpler, less painful, and more accurate way. Such a setup could be handy for cyclists who need to monitor sodium levels to prevent dehydration, and anemic patients who need to track their blood oxygen levels, the article said. Clark presented this work at the BioMethods Boston conference at Harvard Medical School last week. But for now, the iPhone only takes images of the fluorescence, which the researchers then export to a computer for analysis. She and one of her graduate students, Matt Dubach, are now working to create an iPhone app that would easily measure and record sodium levels. They also hope to get the reader to draw power from the iPhone itself, rather than from a battery. Clark is also working to expand the technology from glucose and sodium to include a wide range of potential targets. “Let’s say you have medication with a very narrow therapeutic range. (Today) you have to try (a dosage) and see what happens," she said. She added the nanosensors could let people monitor the level of a given drug in their blood in real time, allowing more accurate dosing. Also, the researchers hope to soon be able to measure dissolved gases, such as nitrogen and oxygen, in the blood to check respiration and lung function. How it works The tattoos were originally meant as an alternative to finger-prick bloodletting, the standard technique for measuring glucose levels in those with diabetes. Under the system, a solution with carefully chosen nanoparticles is injected into the skin, leaving no visible mark. But the nanoparticles will fluoresce when exposed to a target molecule, such as sodium or glucose —and changes in fluorescence can be detected and tracked by a modified iPhone. The tattoo developed by Clark’s team contains 120-nanometer-wide polymer nanodroplets including a fluorescent dye, specialized sensor molecules designed to bind to specific chemicals, and a charge-neutralizing molecule. Once in the skin, the sensor molecules attract their target because they have the opposite charge. When the target chemical is taken up, the sensor is forced to release ions to maintain an overall neutral charge. This changes the fluorescence of the tattoo when it is hit by light. The more target molecules there are in the patient’s body, the more the molecules will bind to the sensors, and the more the fluorescence changes. While the original reader was a large boxlike device, Dubach designed a modified iPhone case that allows an iPhone to read the tattoos. The case contains a nine-volt battery, a filter that fits over the iPhone’s camera, and an array of three LEDs that produce light in the visible part of the spectrum. A light-filtering lens is placed over the iPhone’s camera, filtering out the light released by the LEDs, but not the light emitted by the tattoo. The device is pressed to the skin to prevent outside light from interfering. — TJD, GMA News