Scientists are making vaccines easier to swallow

Like all the other vaccines, the revolutionary mRNA vaccines need to be injected. This can be a hurdle for many people who fear needles. A research team led by the Massachusetts Institute of Technology (MIT) has recently developed a way of delivering RNA in a capsule that can be easily swallowed, hoping that this new technology could make more people receptive to vaccination.

Moreover, in addition to making vaccines easier to tolerate, this approach could also be employed to deliver other types of therapeutic RNA or DNA directly into the digestive tract and treat a variety of gastrointestinal diseases such as ulcers.

“Nucleic acids, in particular RNA, can be extremely sensitive to degradation particularly in the digestive tract. Overcoming this challenge opens up multiple approaches to therapy, including potential vaccination through the oral route,” said study senior author Giovanni Traverso, an expert in Biomedical Engineering at MIT and a gastroenterologist at Brigham and Women’s Hospital in Boston.

In their new experimental study, Professor Traverso and his colleagues managed to develop a capsule that could deliver up to 150 micrograms of RNA (which is more than the amount used in COVID-19 vaccines) in the stomach of pigs. This research is built upon previous studies in which they developed new ways to deliver solid drugs, such as insulin, into the lining of the stomach.

Since nucleic acids are susceptible to degradation when entering the body, they need to be carried by protective particles. The scientists developed a new type of polymer called poly(beta-amino esters), which seemed to be much more effective than linear polymers at protecting nucleic acids and delivering them into cells. They also discovered that using two of these polymers together was more effective than using only one. 

“We made a library of branched, hybrid poly(beta-amino esters), and we found that the lead polymers within them would do better than the lead polymers within the linear library,” explained study co-author Ameya Kirtane, a postdoctoral fellow at MIT. “What that allows us to do now is to reduce the total amount of nanoparticles that we are administering.”

Although the reporter proteins showing that cells have been successful in absorbing RNA have been detected in pigs’ stomachs after the delivery of the capsules, they have not been found elsewhere in their organisms. Further experimental research is needed to manage to increase RNA uptake in other organs, by changing the composition of the nanoparticles or providing larger doses. 

However, scientists believe that it may also be possible to generate strong immune responses with delivery only to the stomach. “There are many immune cells in the gastrointestinal tract, and stimulating the immune system of the gastrointestinal tract is a known way of creating an immune response,” said study lead author Alex Abramson, a postdoctoral researcher at MIT.

The study is published in the journal Matter.

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By Andrei Ionescu, Earth.com Staff Writer