It's not on the market yet, but a patch composed of tiny needles, each the width of a few human hairs, could eventually replace hypodermic needles for most drug injections. Preliminary experiments with people with diabetes have shown that the patch can deliver insulin successfully and with less pain than a hypodermic.

The "micro-needle patch" uses dozens of extremely thin, short, drug-saturated needles to deliver medicine. The needles penetrate the skin far enough to reach capillaries, which then carry the drug throughout the body. Because the needles are so thin, they cause little or no pain during an injection-a crucial element in what researchers believe could become an extremely popular method of drug delivery.

Mark Prausnitz, a drug delivery expert at the Georgia Institute of Technology who has studied micro-needle patches, thinks that the patches, by removing the intimidating aspects of injections, will increase adherence to drug dose schedules among patients who must take shots.

Beyond that, Prausnitz sees the patches as giving people the ability to administer vaccines to themselves, which could increase the number of people getting vaccinations. And in the event of a pandemic, government agencies could simply mail micro-needle patches within days to virtually the entire country, eliminating the potential for hospitals to be inundated by crowds of vaccine seekers. 

An even more intriguing possibility, Prausnitz says, is that the patch could replace the monthly injection of medication into the back of the eye that people with macular degeneration currently endure. Instead, a painless micro-needle patch could be placed over the surface of the eye to deliver medication that would migrate through the eye to the retina.