Scientists developed a microneedle ‘vaccine patch’ that promises a much greater immune reaction than traditional vaccine shots and all without the potential pain & anxiety associated to conventional needles.
While microneedle patches are in development for years, they have proved difficult to successfully manufacture at scale. What’s more, it can be challenging to adapt the same patch for various types of vaccine.
This new research overcomes those problems with an advanced 3D-printing technique called Continuous Liquid Interface Production or CLIP, using ultraviolet light and a special resin to make the patches (patches that are consistent in size, shape & needle spacing, no matter how many are made.)
“Our approach allows us to directly 3D-print microneedles, which provides us lots of design latitude for making the best microneedles from a performance & cost point-of-view,” says microbiologist Shaomin Tian from University of North Carolina at Chapel Hill.
The ease & speed with which these microneedle patches can be developed could bring them into much wider use, researchers say. Besides avoiding conventional needles altogether, another advantage of those patches is that they can be self-administered, it means, there is no need to book an appointment with a doctor or a nurse to get your shot.
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This is because short needles only need to penetrate slightly below the surface layer of the skin (transdermal) and not all the way through it (subcutaneous), like traditional vaccines.
The drugs get directly-delivered in the vicinity of skin immune cells, which is perfect for vaccines. With a more efficient delivery system, it is possible that dosages can be lowered accordingly.
In lab tests in mice, researchers found that their patch generated a T-cell and antigen-specific antibody response some 50 times greater than a traditional, subcutaneous injection delivered under the surface of skin.
“Using model vaccine components, we demonstrated that 3D-printed microneedle delivery resulted in enhanced cargo retention in the skin, activation of immune cells & stronger humoral and cellular immune responses as compared with traditional vaccination routes,” researchers explain in their paper.
The team says that its design & approach can be adapted to cover vaccines for flu, measles, hepatitis & even COVID-19. There is no need for special handling or refrigeration in terms of transportation, which could help boost vaccination rates. The patches even can use recent improvements in the field to combine multiple drugs on the same patch.
While patches have yet to be tested on humans, similar benefits should apply as are seen in mice, enabling faster & more efficient vaccine responses to epidemics & pandemics in the future.
The researchers are not standing still with their microneedle vaccine patch, next, they are watching how RNA vaccines (including Pfizer & Moderna COVID-19 vaccines) could be incorporated into this design.
“In developing this technology, we hope to set the inspiration for even more rapid global development of vaccines, at lower doses, in a pain & anxiety-free manner,” says chemical engineer Joseph DeSimone from the Stanford University .
The research has been published in PNAS.