July 19, 2010
‘Microneedle’ Skin Patch May Replace Flu Shot
Researchers at Georgia Institute of Technology and Emory University have invented a painless vaccine-delivery system that may one day allow flu shots to be delivered by mail.
The new system replaces a conventional large needle with hundreds of tiny dissolvable ones embedded in a skin patch, and may even generate a better immune response than a conventional shot.
The microneedles come attached to a Band-Aid like skin patch, and are so small they cannot be felt. They scarcely penetrate the skin before dissolving and releasing their vaccine.
Mark Prausnitz of Georgia Institute of Technology, who led the research in collaboration with researchers at Emory University, likened the business side of the patch to fine sandpaper.
Some medications that are already available, such as nicotine patches that help people quit smoking, work by simply allowing the medication to be absorbed by the skin. However, attempts to use this approach to deliver a flu vaccine have been unsuccessful so far.
But the Georgia Tech vaccine is different in that it is still injected, but the microscopic size of the needles mean the shots do not hurt, and that no specialized training is required to administer them.
"The goal has been a means to administer the vaccine that is patient friendly," Mr. Prausnitz told The Associated Press (AP).
Indeed, the approach does away with two of the biggest problems associated with vaccines: patients' fear of needles, and disposal of leftover hypodermic needles.
The researchers wanted to find a solution that was "not only not hurting or looking scary, but that patients could self-administer," he said.
The dissolvable needles mean there are no leftover sharp needles, something of particular importance for those who may administer the vaccine themselves at home, he explained.
Such a system might make people more likely to get the vaccine, he said.
The patch has already been tested on mice, and the researchers are seeking additional funding to begin tests in people. If the human tests are successful, the new patch could be available for use in five years, Prausnitz said.
The tiny microneedles are 650 microns (three-hundredths of an inch) in length, with 100 placed on the patch used in the mouse study -- enough to successfully deliver the proper amount of vaccine.
The patch is placed on the skin for 5 to 15 minutes, but can remain longer without doing any damage, Prausnitz said.
Doctors recommend that nearly everyone get a flu vaccine every year, but many people don't because it can be inconvenient. However, if people can receive their shot in the mail, or perhaps at a local pharmacy, they may choose to do so, Prausnitz said.
When asked if the term "microneedle" might still make some "shot averse" people nervous, Prausnitz said he was confident that marketers would develop a better term before the new system would hit the market.
The research was supported by the National Institutes of Health, and was reported online July 18 in the journal Nature Medicine.
Image 1: An array of 36 dissolving microneedles is shown here on a fingertip for size comparison. (Credit: Jeong-Woo Lee)
Image 2: This is the first image in a sequence showing how the microneedles dissolve in the skin. This image shows the microneedles before application to the skin. (Credit: Sean Sullivan)
Image 3: This image shows microneedles that have partially dissolved one minute after being pressed into pig skin. (Credit: Sean Sullivan)
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