Researchers at Emory University and the Georgia Institute of Technology report on a painless transdermal vaccination technology based on the use of vaccine-loaded microneedles that dissolve into the skin. When tested in mice, the polymer microneedle technology was found to provide better protection against flu than injections using traditional syringes.
The approach has been developed through a collaboration led by Richard Compans, Ph.D., professor of microbiology and immunology at Emory University School of Medicine, and Mark Prausnitz, Ph.D., a professor at the Georgia Tech School of Chemical and Biomolecular Engineering. They claim the platform could allow governments to distribute vaccines for self-administration during pandemics and simplify large-scale immunization programs in developing countries. The researchers have now been awarded $11.5 million in NIH grant funding to further develop the technology over the next five years. They report on their studies in the advanced online issue of Nature Medicine in a paper titled “Dissolving polymer microneedle patches for influenza vaccination.”
The microneedle arrays used for the reported mouse experiments were composed of polyvinylpyrrolidone polymer mixed with freeze-dried flu vaccine. Each patch contained 100 microneedles of 650 microns length. The authors claim that when tested in animals, the patches generated “robust antibody and cellular immune responses in mice that provided complete protection against lethal challenge.” In comparison with traditional injection-based vaccination the patch approach also resulted in “more efficient lung virus clearance and enhanced cellular recall responses after challenge,” they write.
The collaborators at Emory and Georgia have been working since the mid 1990s to develop microneedle technology for painless drug and vaccine delivery through the skin. Professor Compans points out that the skin represents an attractive site for immunization because it contains many types of cells involved in generating immune responses to vaccines. However, because the needles are so short they don’t actually reach the nerve endings and so cause no pain. Another major advantage of the technology is that it requires no skill or training to apply and doesn’t require the disposal of used syringes and needles.
“The NIH grants will allow us to move forward with perfecting the manufacturing process, refining the techniques for optimally inserting the microneedles into the skin, and ensuring that vaccine delivered this way produces the necessary immune response,” Professor Prausnitz remarks. “We expect that this research will lead to a better way of delivering the flu vaccine, which will allow more people who need it to receive the immunization in a convenient and effective way. Beyond that, the possibility of replacing a hypodermic needle with a microneedle patch should significantly impact the way that other vaccines are delivered.”
In April NIH awarded Emory and the University of Georgia a $32.8 million, seven-year contract to establish the Emory/UGA Influenza Pathogenesis and Immunology Research Center, for which Compans is principal investigator. 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 identifying new immune targets for antiviral medicines.