Patches containing micron-scale needles that carry vaccine with them as they dissolve into the skin could simplify immunization programs by eliminating the use of hypodermic needles -- and their "sharps" disposal and re-use concerns. Applied easily to the skin, the microneedle patches could allow self-administration of vaccine during pandemics and simplify large-scale immunization programs in developing nations.

Details of the dissolving microneedle patches and immunization benefits observed in experimental mice were reported July 18th in the advance online publication of the journal Nature Medicine. Conducted by researchers from Emory University and the Georgia Institute of Technology, the study is believed to be the first to evaluate the immunization benefits of dissolving microneedles. The research was supported by the National Institutes of Health (NIH).

"In this study, we have shown that a dissolving microneedle patch can vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle," said Mark Prausnitz, a professor in the Georgia Tech School of Chemical and Biomolecular Engineering.

Just 650 microns in length and assembled into an array of 100 needles for the mouse study, the dissolving microneedles penetrate the outer layers of skin. Beyond their other advantages, the dissolving microneedles appear to provide improved immunity to influenza when compared to vaccination with hypodermic needles.

"The skin is a particularly attractive site for immunization because it contains an abundance of the types of cells that are important in generating immune responses to vaccines," said Richard Compans, professor of microbiology and immunology at Emory University School of Medicine.

In the study, one group of mice received the influenza vaccine using traditional hypodermic needles injecting into muscle; another group received the vaccine through dissolving microneedles applied to the skin, while a control group had microneedle patches containing no vaccine applied to their skin. When infected with influenza virus 30 days later, both groups that had received the vaccine remained healthy while mice in the control group contracted the disease and died.

Three months after vaccination, the researchers also exposed a different group of immunized mice to flu virus and found that animals vaccinated with microneedles appeared to have a better "recall" response to the virus and thus were able to clear the virus from their lungs more effectively than those that received vaccine with hypodermic needles.

"Another advantage of these microneedles is that the vaccine is present as a dry formulation, which will enhance its stability during distribution and storage," said Ioanna Skountzou, an Emory University assistant professor.

Pressed into the skin, the microneedles quickly dissolve in bodily fluids, leaving only the water-soluble backing. The backing can be discarded because it no longer contains any sharps.

"We envision people getting the patch in the mail or at a pharmacy and then self administering it at home," said Sean Sullivan, the study’s lead author from Georgia Tech. "Because the microneedles on the patch dissolve away into the skin, there would be no dangerous sharp needles left over."

The microneedle arrays were made from a polymer material, poly-vinyl pyrrolidone, that has been shown to be safe for use in the body. Freeze-dried vaccine was mixed with the vinyl-pyrrolidone monomer before being placed into microneedle molds and polymerized at room temperature using ultraviolet light.

In many parts of the world, poor medical infrastructure leads to the re-use of hypodermic needles, contributing to the spread of diseases such as HIV and hepatitis B. Dissolving microneedle patches would eliminate re-use while allowing vaccination to be done by personnel with minimal training.

Though the study examined only the administration of flu vaccine with the dissolving microneedles, the technique should be useful for other immunizations. If mass-produced, the microneedle patches are expected to cost about the same as conventional needle-and-syringe techniques, and may lower the overall cost of immunization programs by reducing personnel costs and waste disposal requirements, Prausnitz said.

Before dissolving microneedles can be made widely available, however, clinical studies will have to be done to assure safety and effectiveness. Other vaccine formulation techniques may also be studied, and researchers will want to better understand why vaccine delivery with dissolving microneedles has been shown to provide better protection.

Beyond those already mentioned, the study involved Jeong-Woo Lee, Vladimir Zarnitsyn, Seong-O Choi and Niren Murthy from Georgia Tech, and Dimitrios Koutsonanos and Maria del Pilar Martin from Emory University.

"The dissolving microneedle patch could open up many new doors for immunization programs by eliminating the need for trained personnel to carry out the vaccination," Prausnitz said. "This approach could make a significant impact because it could enable self-administration as well as simplify vaccination programs in schools and assisted living facilities."

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Media Relations Contacts: John Toon, Georgia Tech (404-894-6986) (jtoon@gatech.edu), Holly Korschun, Emory University (404-727-3990) (hkorsch@emory.edu) or Abby Vogel Robinson, Georgia Tech (404-385-3364) (abby@innovate.gatech.edu).

Writer: John Toon

It's enough to make a kid scream. A shot can be an unpleasant experience for anyone, no matter the age. Funding by government flu grants, researchers at Georgia Tech and Emory University in Atlanta developed a solution - needles so small, you can't feel them. It's as long as one or a few hairs are thick, said Georgia Tech researcher, Mark Prausnitz. They're called microneedles, so tiny they only go part of the way through the skin, just deep enough to work but not enough to hit nerves and actually hurt. Research shows microneedles might be more effective than traditional shots, and perhaps the biggest advantage, they're so simple, people can vaccinate themselves. If all goes well, researchers say in five years, microneedles could make doctors' visits a little more pain-free. Brooke Baldwin, CNN, Atlanta. To view the segment, go to following link to open file: CNN Video

To view Georgia Tech article: Flu Vaccine Given In Microneedle Patches

The research was published in the early online edition of the journal Proceedings of the National Academy of Sciences (PNAS). Another study by the research team on a different influenza strain was described in the journal Public Library of Science (PLoS) One.

The patches used in the experiments contained an array of stainless steel microneedles coated with inactivated influenza virus. The patches were pressed manually into the skin and after a few minutes, the vaccine coating dissolved off within the skin. The coated microneedle immunizations were compared to conventional intramuscular hypodermic injections at the same dose in another group of mice.

The researchers found that the microneedle vaccinations induced strong immune responses against influenza virus that were comparable to immune responses induced by the intramuscular, hypodermic immunizations. One month after vaccination, the researchers infected both groups of mice with a high dose of influenza virus. While all mice in a control group of unvaccinated mice died of influenza, all mice in both the hypodermic and the microneedle groups survived.

"Our findings show that microneedle patches are just as effective at protecting against influenza as conventional hypodermic immunizations," says Richard Compans, PhD, Emory professor of microbiology and immunology and one of the paper's senior authors. "In addition, vaccine delivery into the skin is desirable because of the skin's rich immune network."

Even though cutaneous immunization has been shown to induce a broad range of immune responses, and to be especially effective in individuals over age 60, this method has not been widely used because it has not been convenient and has required highly trained personnel.

"Unlike conventional hypodermic injections, microneedles are prepared in a patch for simple administration, possibly by patients themselves, and inserted painlessly onto the skin without specialized training," says Mark Prausnitz, PhD, professor in the Georgia Tech School of Chemical and Biomolecular Engineering and co-senior author. "These micron-scale needles can be mass produced using low-cost methods for distribution to doctors' offices, pharmacies and, possibly, people's homes."

Other advantages of the microneedle patches could include more convenient storage, easier transportation and lower dosage requirements. Lower doses could be particularly important because flu vaccine production capacity sometimes is limited for seasonal vaccine, and a future influenza pandemic would require much greater production of vaccine.

Replacing a hypodermic needle with a microneedle patch also could significantly impact the way other vaccines are delivered, and could be particularly beneficial in developing countries. A microneedle patch could fit inside an envelope for delivery by the postal service and would occupy much less storage space. Patches also would increase vaccine safety by reducing the dangers of accidental or intentional hypodermic needle re-use.

The project team plans future immunization studies in other animal models, including guinea pigs or ferrets, before initiating studies in humans. Also, more studies are needed to determine the minimum vaccine dose needed for full protection.

The Emory and Georgia Tech research team began developing the new microneedle vaccine patch technology in 2007 using grants from the National Institutes of Health (NIH). The project team has extensive experience in microneedle development, influenza vaccines, vaccine delivery systems, product development and interdisciplinary collaboration.

In 2007 the NIH awarded a $32.8 million, seven-year contract to Emory, along with the University of Georgia, to establish the Emory/UGA Influenza Pathogenesis and Immunology Research Center. The center is working to improve the effectiveness of flu vaccines through a number of different projects studying how influenza viruses attack their hosts, how they are transmitted, and what new immune targets might be identified for antiviral medicines.

Prausnitz and his colleagues have been working since the mid 1990s to develop microneedle technology for painless drug and vaccine delivery through the skin. The Georgia Tech team has also developed manufacturing processes for microneedle patches and tested the ability of the needles to deliver proteins, vaccines, nanoparticles, and other small and large molecules through the skin.

Other authors of the papers are Emory microbiologists Ioanna Skountzou and Chinglai Yang, and first authors Ling Ye, Qiyun Zhu, Dimitrios Koutsonanos, and Maria del Pilar Martin from Emory and Vladimir Zarnitsyn from Georgia Tech. Other authors and contributors were Yulong Gao, Lei Pan, and Zhiyuan Wen from Emory, and Harvinder Gill and Sean Sullivan from Georgia Tech.