The team, from Stanford University and the University of North Carolina at Chapel Hill, published its study conducted on animals in Proceedings of the National Academy of Scientists. According to its findings, the patch gave an immune response ten times greater than a vaccine delivered into an arm muscle with a needle.
Described as a breakthrough, the patch consists of 3D printed microneedles lined up on a polymer patch. Applied directly to the skin with the ability to be self-administered, the patch is said to provide a less invasive, easy and painless alternative to a vaccine shot.
Study results showed that the vaccine patch generated a significant T-cell and antigen-specific antibody response that was 50 times greater than a subcutaneous injection delivered under the skin.
Researchers believe the heightened immune response could lead to dose sparing, with a microneedle vaccine patch using a smaller dose to generate a similar immune response as a vaccine delivered with a needle and syringe.
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Microneedle patches have been studied for decades, but the team's work aims to overcome previous challenges of adaptation through 3D printing. The microneedles can be customised to develop various vaccine patches for flu, measles, hepatitis or Covid-19.
Lead study author Shaomin Tian, researcher in the Department of Microbiology and Immunology in the UNC School of Medicine, said that this issue coupled with manufacturing challenges has arguably held back the field of microneedles for vaccine delivery.
Most microneedle vaccines are fabricated with master templates to make moulds, however this is not very versatile and can lead to reduced needle sharpness during replication.
“Our approach allows us to directly 3D print the microneedles which gives us lots of design latitude for making the best microneedles from a performance and cost point of view,” Tian said.
The patches were 3D printed at the UNC using a CLIP prototype 3D printer invented by lead study author Joseph M. DeSimone, professor of translational medicine and chemical engineering at Stanford University and professor emeritus at UNC-Chapel Hill.
The team is now formulating RNA vaccines, like the Pfizer and Moderna vaccines, into microneedle patches for future testing.
“In developing this technology, we hope to set the foundation for even more rapid global development of vaccines, at lower doses, in a pain and anxiety free manner,” said DeSimone.
“One of the biggest lessons we’ve learned during the pandemic is that innovation in science and technology can make or break a global response. Thankfully we have biotech and health care workers pushing the envelope for us all.”