Tuesday, July 14, 2015

Dissolving Microneedle Vaccinations

Researchers recently demonstrated that a flu vaccine delivered using microneedles that dissolve in the skin can protect people against infection even better than the standard needle-delivered vaccine.

The new microneedle patch is made of dissolvable material, eliminating needle-related risks. Not to mention the sea change it may mean for patients with severe needle anxiety!  I suspect this approach may also be more tolerable for many patients than oral and nasal vaccination methods. It is also easy to use without the need for trained medical personnel—making it ideal for use where healthcare resources are limited.

“Our novel transcutaneous vaccination using a dissolving microneedle patch is the only application vaccination system that is readily adaptable for widespread practical use,” said Professor Shinsaku Nakagawa, one of the authors of the study from Osaka University. “Because the new patch is so easy to use, we believe it will be particularly effective in supporting vaccination in developing countries.”

The new microneedle patch – MicroHyala – is dissolvable in water. The tiny needles are made of hyaluronic acid, a naturally occurring substance in tissue matrix and the synovial fluid that cushions the joints. When the patch is applied sort of like a Band-Aid, the needles pierce the epidermis of skin and dissolve into the body, taking the vaccine with them.

The researchers compared the new system to traditional needle delivery by vaccinating two groups of people against three strains of influenza: A/H1N1, A/H3N2 and B. None of the subjects had a bad reaction to the vaccine, showing that it is safe to use in humans. The patch was also effective: people given the vaccine using the microneedles had an immune reaction that was equal to or stronger than those given the vaccine by injection.

“We were excited to see that our new microneedle patch is just as effective as the needle-delivered flu vaccines, and in some cases even more effective,” said Professor Nakagawa.

Previous research has evaluated the use of microneedles made of silicon or metal, but they were not shown to be safe. Microneedles made from these materials also run the risk of breaking off in the skin, leaving tiny fragments behind. The new dissolvable patch eliminates this risk because the microneedles are designed to dissolve in the skin.

What can we use from this in teaching undergraduate A&P?

  • Consider mentioning this advance when discussing the layers of the skin, this giving a clinical application to pique student interest.

  • When discussing immunity and vaccination, consider mentioning this discovery.

  • If you discuss hyaluronic acid when covering histology, this information may help students realize the importance of knowing such details because of clinical applications of materials science.

Want to know more?

  • Clinical study and stability assessment of a novel transcutaneous influenza vaccination using a dissolving microneedle patch.
    • Sachiko Hirobe, et al. Biomaterials. Vol 57 (July 2015), Elsevier. doi: 10.1016/j.biomaterials.2015.04.007
    • The original research article.
    • my-ap.us/1eXzAud

Microneedle image courtesy of S. Nakagawa
Some content adapted from an Elsevier newsroom release