MIT researchers have managed to print vaccine-filled microneedle patches that can be stored long-term at room temperature.
A team at Massachusetts Institute of Technology (MIT) has developed a mobile vaccine printer that, if scaled appropriately, could produce hundreds of vaccine doses per day.
This technology would solve many of the challenges of increasing global access to vaccines: chiefly the need for infrastructure capable of sustaining doses in sub-zero temperatures, as well as syringes, needles and trained healthcare professionals to administer them.
In contrast, the machine built by the MIT team can print patches containing hundreds of microneedles containing vaccines. The patch can be stuck to the skin, which allows the vaccine to dissolve without the need for a traditional injection. Once printed, the patches can be stored at room temperature for months.
This type of printer, which fits on a table, could be used anywhere vaccines are needed, such as. B. in remote villages, refugee camps or military bases to allow rapid vaccination of large numbers of people.
“We could one day have on-demand vaccine production,” said Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research. “For example, if there was an Ebola outbreak in a certain region, you could send a couple of these printers there and vaccinate people there.”
Photo credit: MIT
The MIT team began researching this technology before Covid-19 to develop a device that could rapidly produce and deploy vaccines during outbreaks of diseases like Ebola.
Instead of making traditional injectable vaccines, the researchers decided to work with a novel mode of vaccine delivery based on patches about the size of a thumbnail containing hundreds of microneedles. These types of vaccines are currently being developed for many diseases, including polio, measles, and rubella. When the patch is placed on the skin, the tips of the needles dissolve under the skin, releasing the vaccine.
“When Covid-19 began, concerns about vaccine stability and vaccine access motivated us to try to incorporate RNA vaccines into microneedle patches,” said postdoc John Daristotle.
The “ink” the researchers use to print the microneedles contains vaccine molecules encapsulated in lipid nanoparticles, which helps them remain stable over long periods of time. It also contains polymers that are easily shaped into the right shape and remain stable for weeks or months.
The researchers found that a 50/50 combination of polyvinylpyrrolidone and polyvinyl alcohol, both commonly used to make microneedles, has the best combination of stiffness and stability.
Inside the printer, a robotic arm injects ink into microneedle molds, and a vacuum chamber under the mold sucks the ink down, making sure the ink reaches the tips of the needles.
To test the printer, the researchers used it to make a Covid-19 microneedle vaccine. They then vaccinated mice with two doses of the vaccine four weeks apart and then measured their antibody response to the virus.
The results showed that mice vaccinated with the microneedle patch responded similarly to mice vaccinated with a conventional injected RNA vaccine. The researchers also saw the same strong antibody response when they inoculated mice with microneedle patches that had been stored at room temperature for up to three months.
“This work is particularly exciting because it realizes the ability to produce vaccines on demand,” said Joseph DeSimone, a professor of translational medicine and chemical engineering at Stanford University who was not involved with the research. “With the ability to expand vaccine manufacturing and improve stability at higher temperatures, mobile vaccine printers can facilitate widespread access to RNA vaccines.”
While the study focused on Covid-19 RNA vaccines, the researchers plan to adapt the process to make other types of vaccines, including vaccines made from proteins or inactivated viruses, the team said.
The current prototype can produce 100 patches in 48 hours, but researchers believe future versions could be scaled to a higher capacity.
The researchers’ findings were published in an article published in the journal Nature Biotechnology.
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