One patch instead of three injections
Microneedle technology developed at the University of Connecticut to provide immunization against infectious diseases has recently been tested in preclinical studies.
The concept of a single vaccine, which is recognized by the World Health Organization (WHO) as the preferred vaccination approach, has been developed for many years. Research on the creation of such a vaccine for a single injection led in 2017 to the technology of stamped assembly of the polymer layer SEAL (StampEd Assembly of Polymer Layer). The author is Thanh Nguyen, who created micro-vaccines for single use, which can release the active substance several times after a certain time, simulating several injections.
However, a large needle was required to inject such microparticles. In addition, there was a limit on the number of particles that could be loaded into the syringe, which limits the dosage of the vaccine.
To overcome these problems, Nguyen's group has developed a skin patch with microneedles that requires only a single injection to perform exactly the same programmable delayed release of the vaccine as the microparticle-derived SEAL.
The microneedle patch avoids painful injections, offering a significant benefit for patients. Extensive studies have shown that the patch with microneedles is practically painless and can be used by patients independently. It is small, portable and similar to a nicotine patch, it can be distributed to people for use in the event of a pandemic in order to quickly form collective immunity on a global scale.
Microneedles have a core and a shell. The shell is made of a biodegradable medical polymer approved by the FDA for implants. It has a unique property of releasing the drug, which allows you to pre-program the pulse intake of vaccines into the body for a period of several days to a month or more from a single dose. Microneedles easily enter the dermal layer of the skin thanks to the miniature tips and smooth geometry of the needles.
To create a patch with microneedles, the researchers adapted SEAL technology to assemble various components of the microneedle, including the tip, shell and core of the vaccine. These components are produced in an additive manner resembling 3D printing, resulting in an array of microneedles over a large area.
Nguyen's group has developed a number of new techniques to improve the existing SEAL technology. The key novelty of the production process is that the vaccine droplets are shaped into the microneedle core and simultaneously inserted into arrays of microneedle shells, offering a manufacturing method on a production scale. This is an important advantage compared to the previously described SEAL and other traditional methods of manufacturing vaccine carriers, in which the active substance is slowly filled separately into each polymer shell or carrier.
In preclinical studies, the group placed a patch with microneedles filled with a clinically available vaccine (preventar-13) on the skin of rats. The use of the patch did not cause skin irritation during prolonged exposure and caused a high immune response against a lethal dose of pneumococcal bacteria. The results of a single injection were similar to those obtained with multiple injections of the same vaccine for about two months.
Despite the encouraging results, additional research is needed to introduce the patch with microneedles into clinical practice. Researchers have demonstrated the possibility of using a patch for pneumococcal vaccines, but different vaccines require different stabilization strategies so that they can work for a long period of implantation into the skin.
The researchers are also working on optimizing and automating the manufacturing process to reduce the cost of a microneedle patch for clinical use. Further studies on larger animals are also needed to test the safety and effectiveness of the microneedle patch.
Article by K.T.M.Tran et al. Transdermal microneedles for the programmable burst release of multiple vaccine payloads is published in the journal Nature Biomedical Engineering.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on UConn materials: Research Proves The Viability of Injection-free Microneedle Technology for Single-Administration of Vaccines.