Microneedles are more powerful than injections
A group of researchers from Stanford University and the University of North Carolina at Chapel Hill have developed a simple and effective method of vaccination using a patch with microneedles created using three-dimensional printing.
Such vaccine administration is painless, less invasive than traditional injection, does not require refrigeration equipment for storage and can be performed independently.
The trick is to apply the vaccine patch directly to the skin, which contains many immune cells, which are the point of application of vaccines.
Such a pronounced immune response will save the active drug: to create a similar immune response, a patch with microneedles uses a smaller dose than a vaccine delivered with a needle and syringe.
The idea of patches with microneedles is not new, but in this study it has received significant improvements. So, thanks to 3D printing, microneedles can be easily changed to create patches with vaccines against various infectious diseases, including influenza, measles, hepatitis or COVID-19.
Advantages of the vaccine patch
Usually, a visit to a clinic or hospital is required to receive the vaccine. A medical worker takes the vaccine out of the refrigerator or freezer, dials it into a syringe and injects it into the arm.
Although this process seems simple, there are problems that can interfere with mass vaccination – from organizing the correct storage of vaccines to the need for trained specialists who can give injections.
New patches with microneedles with a vaccine coating that dissolve in the skin can be delivered anywhere in the world without special treatment, special storage conditions, and people at home will be able to stick it on their own skin. This is very important, since the availability and ease of use of a vaccine patch can lead to an increase in the level of vaccination.
How microneedles are made
As a rule, most microneedles are made using press templates. However, this molding reduces the sharpness of the needles during replication. The new approach allows you to directly print microneedles on a 3D printer, which gives ample opportunities to create microneedles of higher quality and at lower cost.
Microneedles have a special faceted design.
The faces on the microneedles increased their surface area compared to the smooth design, which ultimately led to improved fixation on the surface of the components of the model vaccine (ovalbumin and CpG). Using fluorescent imaging tags on live animals, the researchers assessed the accumulation and bioavailability of vaccines in vivo in mice, depending on the method of administration. Compared with traditional subcutaneous injection, percutaneous delivery using microneedles led to increased accumulation of vaccines in the skin and more pronounced activation of immune cells in the lymph nodes. In addition, the microneedle vaccine induced a powerful humoral immune response – the total level of immunoglobulin G (IgG) on day 30 after vaccination was up to 50 times higher than after subcutaneous injection, which could potentially help reduce the dose of the drug. Vaccination with a patch also triggered T-cell reactions.
Thus, 3D-printed microneedles coated with vaccine components create the basis for effective, non-invasive, self-vaccination.
A group of microbiologists and chemical engineers continues to innovate, developing RNA vaccines in the form of patches with microneedles for future research.
The article by C.Caudill et al. Transdermal vaccination via 3D-printed microneedles induces potential humoral and cellular immunity is published in the journal Proceedings of the National Academy of Sciences.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of North Carolina: A 3D-printed vaccine patch offers vaccination without a shot.