Novel vaccine printer can generate 100 thumbnail

In a paper published Monday on Nature Biotechnology, MIT researchers have devised a solution to this problem — a mobile vaccine printer that could be scaled up to produce hundreds of vaccines in a day. The printer can easily fit on a tabletop and can be deployed anywhere.

"We could someday have on-demand vaccine production," Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research and senior author of the study, said in a statement. "If, for example, there was an Ebola outbreak in a particular region, one could ship a few of these printers there and vaccinate the people in that location."

The researchers demonstrated that the printer could produce thermostable Covid-19 RNA vaccines that could induce a "comparable immune response" to that generated by injected RNA vaccines in mice.

"Ink" used to print microneedles includes RNA vaccine molecules

The printer developed can produce patches about the size of a thumbnail with hundreds of microneedles containing the vaccine. Such 'patches' are now in development for diseases like polio, measles, and rubella. When the patch is applied to the skin, the needle tips dissolve, releasing the vaccine. These patches can be stored for months at room temperature.

"When Covid-19 started, concerns about vaccine stability and access motivated us to try to incorporate RNA vaccines into microneedle patches," lead author and postdoc John Daristotle said.

So, how does this work?

The "ink" used to print the microneedles includes RNA vaccine molecules in lipid nanoparticles, which ensures their stability for a long time. It also contains polymers that can be molded into the right shape. And a 50/50 combination of polyvinylpyrrolidone and polyvinyl alcohol, commonly used to form microneedles, had the best combination of stiffness and stability.

Inside the printer, a robotic arm injects ink into microneedle molds, and a vacuum chamber below the mold sucks the ink down to the bottom. The molds take a day or two to dry once filled.

The researchers tested their Covid-19 micro vaccine needle on mice; the animals were given two doses, four weeks apart, and their antibody response was measured. The mice vaccinated with the microneedle patch responded similarly to those vaccinated with a traditional, injected RNA vaccine. They also demonstrated the same strong antibody response.

Though this study focused on Covid-19 RNA vaccines, the researchers will adapt the process to produce other types of vaccines, including vaccines made from proteins or inactivated viruses.

The current prototype can produce 100 patches in 48 hours, but the researchers anticipate that future versions could be designed to have higher capacity.