Brian Wang writes "Pre-cursors of the nanotech medical cures are being tested in rats. Mem capsules with 7 nm holes let out insulin from cells inside the capsule. The holes allow nutrients in to keep the cells alive but keep out the immune system cells to keep the cells alive. Since the cells and the capsules last basically the lifetime of the person, they are effectively a cure. They will take some years to go through long term small animal trials and then to monkey and finally to human trials. The technique can be applied to other diseases. Parkisons, hemofilia etc… http://www.wired.com/news/technology/0,1282,47934, 00.html"
Additional information about the device can found in this NSF press release.